◄   Carnets Geol. 6 (M01)   ►

Contents

[Introduction] [Biostratigraphy] [Systematic descriptions]
[Family Deshayesitidae Stoyanow, 1949]
[1) Genus Deshayesites Kasansky, 1914]
[2) Genus: Paradeshayesites Kemper, 1967]
[3) Genus: Dufrenoyia Kilian et Reboul, 1915]
[Summary and discussion ...] [Conclusion]
[References] [Figures] and ... [Plates]

The Deshayesitidae Stoyanov, 1949 (Ammonoidea) of the Aptian historical stratotype region at Cassis-La Bédoule (SE France)

Pierre Ropolo

Centre de Sédimentologie-Paléontologie, CNRS UMR 6019, Université de Provence Marseille-Saint-Charles (France) & Centre d'Études Méditerranéennes, Barrême (France) - Correspondance: 83 Bd. du Redon, Bât. E-9, La Rouvière 13009 Marseille (France)

Michel Moullade

Centre de Sédimentologie-Paléontologie, CNRS UMR 6019, Université de Provence Marseille-Saint-Charles (France) & Centre de Recherches Micropaléontologiques, Muséum d'Histoire Naturelle, 60 Bd. Risso, 06000 Nice (France)

Roland Gonnet

Centre d'Études Méditerranéennes, Barrême (France)

Gabriel Conte

9, Rue St Castor, 30000 Nîmes (France)

Guy Tronchetti

Centre de Sédimentologie-Paléontologie, CNRS UMR 6019, Université de Provence Marseille-Saint-Charles (France)

Manuscript online since May 11, 2006

Abstract

One of the significant results of the multidisciplinary investigations carried out during recent years in the Lower Aptian historical stratotype of the Cassis-La Bédoule region (South-Eastern France) was a proposal to update the local Upper Barremian/Lower Aptian ammonite biozonation in order to be more consistent with the standard Mediterranean zonal subdivisions. So the lower and upper boundaries of the Lower Aptian (= Bedoulian substage of most French authors) as well as the boundaries of four biozones (Paradeshayesites tuarkyricus, P. weissi, Deshayesites deshayesi, Dufrenoyia furcata zones) and two subzones (Roloboceras hambrovi and Paradeshayesites grandis subzones) were identified and formally defined in the stratotype. However, to support this zonal scheme additional descriptions and illustrations of the ammonites collected bed by bed in the several sections studied were still required. In this paper we describe the members of the most significant ammonite family found in the Lower Aptian of Cassis-La Bédoule, i.e. the Deshayesitidae, and delimit precisely their stratigraphic positions. As regards zonation, we have replaced the index ammonite of the earliest Bedoulian Zone, i.e. Paradeshayesites tuarkyricus (Bogdanova, 1983), by Paradeshayesites oglanlensis (Bogdanova, 1983), and re-established the Pseudocrioceras waagenoides Zone as a subzone.

Key Words

Cretaceous, Aptian, ammonites, Deshayesitidae, markers, biozonation, taxonomy, stratigraphy

Citation

Ropolo P., Moullade M., Gonnet R., Conte G. & Tronchetti G. (2006).- The Deshayesitidae Stoyanov, 1949 (Ammonoidea) of the Aptian historical stratotype region at Cassis-La Bédoule (SE France).- Carnets de Géologie / Notebooks on Geology, Brest, Memoir 2006/01 (CG2006_M01)

Résumé

Les Deshayesitidae Stoyanov, 1949 (Ammonoidea) de la région du stratotype historique de l'Aptien à Cassis-La Bédoule (SE France).- L'un des résultats significatifs de recherches multidisciplinaires poursuivies ces dernières années dans la région stratotypique de l'Aptien inférieur à Cassis-La Bédoule (SE France) fut de proposer pour le Barrémien supérieur et l'Aptien inférieur une mise à jour de la biozonation locale par ammonites qui soit plus en accord avec les subdivisions zonales standard du domaine méditerranéen. Ainsi les limites inférieure et supérieure de l'Aptien inférieur (= sous-étage bédoulien des auteurs français) de même que les limites de quatre biozones (à Paradeshayesites tuarkyricus, P. weissi, Deshayesites deshayesi, Dufrenoyia furcata) et de deux sous-zones (à Roloboceras hambrovi et Paradeshayesites grandis) ont été reconnues et formellement définies dans le stratotype. Il convenait, à l'appui de ce schéma zonal, de décrire et figurer les ammonites recueillies banc par banc dans les diverses coupes étudiées. Le but du présent article est donc de décrire et de situer stratigraphiquement les représentants de la famille la plus significative parmi les ammonites de l'Aptien inférieur de Cassis-La Bédoule, à savoir les Deshayesitidae. En ce qui concerne la zonation, nous avons remplacé dans un nouveau schéma zonal l'ex-forme-index de la première zone du Bédoulien, Paradeshayesites tuarkyricus (Bogdanova, 1983), par l'espèce Paradeshayesites oglanlensis (Bogdanova, 1983), et rétabli la zone à Pseudocrioceras waagenoides au rang de sous-zone.

Mots-Clefs

Crétacé, Aptien, ammonites, Deshayesitidae, marqueurs, biozonation, taxinomie, stratigraphie

Introduction

Over the years the outcrops of the Lower Aptian stratotype in the Cassis-La Bédoule area (SE France) (Fig. 1 ) have been studied by many authors, including Matheron (1842, 1878-1880), Reynès (1861), Hébert (1871), Toucas (1888), Roch (1927), Blanc (1958), Fabre-Taxy et alii (1965), Flandrin (1965), Moullade et alii (1980), Busnardo (1984), Conte (1994), Moullade et alii (1998, 2000a), Ropolo et alii (2000a, 2000b, 2000c), Ropolo & Gonnet (1999), and Cecca et alii (1999, 2000).

Hébert (1871) was the first to give a lithologic and to some extent a "biostratigraphic" description of the stratotype outcrops, because his description is based on a succession of levels more or less characterized by fossils. The sequence was divided initially into two ammonite zones by Kilian & Reboul (1915) and by Roch (1927); later it was regarded as a single zone by Fabre-Taxy et alii (1965). Busnardo (1984) divided the Lower Aptian of Cassis-La Bédoule into seven zones, from bottom to top: the "Prodeshayesites", Pseudocrioceras coquandi, Deshayesites consobrinus, Ancyloceras matheroni, Roloboceras hambrovi, Deshayesites grandis and Tropaeum bowerbanki zones. Because it appeared difficult to apply this local zonation elsewhere, such a subdivision was not retained for the Mediterranean region at the several Workshops of the Lower Cretaceous Cephalopod Team of IGCP projects 262/362 (Digne 1990 - Mula 1992 - Piobbico 1994 - London 1997). Instead they proposed the ammonite zonation used in the Transcaspian region (Turkmenia), which consists of four zones (from bottom to top: the Deshayesites tuarkyricus, D. weissi, D. deshayesi and Dufrenoyia dufrenoyi zones).

Too, during the last decade reservations have been expressed (Bogdanova & Tovbina, 1994; Erba, 1996; Bogdanova & Mikhailova, 1999; Barragán-Manzo & Mendes-Franco, 2005) concerning the concept of "Bedoulian" (Toucas, 1888) (= the "Cassis-La Bédoule Formation" pro parte, Moullade et alii, 2000b) defined in its historical stratotype by the French authors as the Lower Aptian substage. The main objections raised were:

1) no thorough paleontological revision of the ammonite content of the stratotype had been published after 1965 despite the recommendations made at the Lyon Colloquium (1963) and

2) the stratigraphic scheme published by Busnardo (1984) (without systematic descriptions or illustrations) could not be applied elsewhere. Consequently, several localities in the Caucasian and Transcaspian regions were proposed as "parastratotypes" (Bogdanova & Prozorovsky, 1999) with the intention of clarifying the then current stratigraphic and palaeontologic knowledge which would lead to the establishment of a basis for of an Aptian "standard" zonation of the Mediterranean Realm.

This prospect emphasized the necessity for an update and revision of Uppermost Barremian/Lower Aptian stratigraphy in SE France and more particularly in the historical stratotype area. New investigations were undertaken by an international multidisciplinary team in various sections of the Cassis-La Bédoule area. In carrying out this revision the methods of integrated stratigraphy were used: a combination of the study of the several macro- and microfossils groups, together with a detailed examination of the sedimentological and geochemical (trace-elements and stable isotopes) characteristics of the associated rocks. The results were published in a synthesis volume (Moullade et alii, 2000a).

The new data thus obtained from the Lower Aptian historical stratotype area led us to propose a stratigraphic subdivision which was more closely in agreement with the recently proposed Mediterranean zones and permitted a partial correlation of the standard zonation with that of the Boreal realm (Ropolo et alii, 2000b, 2000c; Moullade et alii, 2000c). The main paleontological (ammonites) and biostratigraphic results published in this synthesis were:

• the description of an uppermost Barremian fossil-rich (Pseudocrioceras) level, presumably equivalent to the Pseudocrioceras coquandi Zone of Busnardo (1984), which allowed us to establish a formal Pseudocrioceras waageni Subzone in the upper portion of the Martelites sarasini Zone (Ropolo et alii, 1999, 2000a, 2000b, 2000c; Cecca et alii, 1999, 2000). This Subzone was later modified as a P. waagenoides Zone (Hoedemaeker & Rawson, 2000) and it was suggested that this zone could be used throughout the whole Tethyan realm.
• the definition of the lower boundary of the Bedoulian substage (therefore the Barremian/Aptian boundary) at the FAD (first appearance datum) of the genus Deshayesites (Delanoy et alii, 1997; Moullade et alii, 1998, 2000a; Ropolo et alii, 1999; 2000c; Gonnet et alii, 2000; Ropolo & Gonnet, 1999; Cecca et alii, 1999, 2000).
• the shift of the Bedoulian/Gargasian boundary, initially thought to be at bed 170 in Cassis-La Bédoule (Fabre-Taxy et alii, 1965), to bed 178, i.e. the top of the Dufrenoyia furcata Zone (Conte, 1994; Moullade et alii, 1998, 2000b; Ropolo et alii, 2000b; Ropolo & Gonnet, 2003).
• the selection of representatives of the family Deshayesitidae (Deshayesites tuarkyricus, D. weissi, D. deshayesi, Dufrenoyia furcata) as zonal index species.

These results have confirmed the importance of the Cassis-La Bédoule area for it is the only place in Europe to present a continuous and expanded succession dated by ammonites ranging from the Upper Barremian (Martelites sarasini Zone) to the Lower/Middle Gargasian.

In this paper, we describe the populations of Deshayesitidae collected in the four zones of the stratotypic Lower Aptian area and define their ranges more accurately. The bed numbering used here is that defined in Moullade et alii (2000b).

Biostratigraphy

Late Barremian / Early Aptian (Bedoulian) biozonation in the stratotypic area of Cassis-La Bédoule (SE France)

Barremian/Aptian boundary

The definition of this limit in the Tethyan Realm was recently discussed by Bogdanova & Mikhailova (2004). These authors synonymize the basal Aptian species Deshayesites antiquus Bogdanova, 1979 and the Barremian species Turkmeniceras tumidum Bogdanova, 1971. The occurrence of the genus Turkmeniceras having been mentioned often at La Bédoule, although never precisely identified or illustrated, the Russian authors assume the presence of a Turkmeniceras level in SE France. In fact, in spite of previous assertions (Conte, oral communication), no specimens of this genus sensu stricto have ever been found in the stratotypic area. Initially we attributed to Deshayesites antiquus some shells which appeared to be quite like one of the type specimens of this species illustrated by Bogdanova (1983, Pl. 2, figs. 6 a-b). However, in 1999 the same ammonite was named Deshayesites aff. antiquus (Bogdanova & Prozorovsky, 1999, p. 68-69, Pl. 2, figs. f-g) and disappeared in subsequent Russian papers (Bogdanova & Mikhailova, 1999, 2004). We have re-studied our specimens more thoroughly and now judge that they show no affinities with the genus Turkmeniceras, because all individuals in our material have narrower and less overlapping whorls. On the other hand, they show many similarities with the paratype of Deshayesites luppovi Bogdanova, 1983, CNIGR Museum 25/9442 (figs. 9 a-b, Pl. 2 in Bogdanova & Mikhailova, 2004), with thirty bifurcated ribs by half whorl and flat or slightly convex flanks. In addition, intermediate ribs appear in the middle of the flanks, a feature which does appear to be present in Turkmeniceras tumidum.

The abundance of heteromorphic ammonites of the genus Pseudocrioceras in the uppermost Barremian beds (45-60) at Cassis-La Bédoule allowed us to individualize this horizon as a subzonal subdivision. We found no specimens of Turkmeniceras sensu stricto either in these levels or in the beds underlying or overlying them. Conversely, no specimen of Pseudocrioceras has as yet been mentioned in the Turkmeniceras levels of Turkmenia. According to Delanoy (oral communication, 2005) the genus Turkmeniceras occurs in several Vocontian localities (Angles, Barrême, Vergons) but in beds of the lowermost Aptian, slightly above the FO of Deshayesites. The recent revision of Moullade et alii (2000a) using integrated stratigraphy shows the succession of beds that spans the Barremian-Aptian transition to be continuous at Cassis-La Bédoule: there is no interruption in sedimentation which might have occulted here the Turkmeniceras level known elsewhere. Because the stratigraphic range of this genus remains uncertain, it cannot be used as a zonal index in SE France. We conclude that at Cassis-La Bédoule as well as in the Caucasus (Georgia) (Kakabadze & Kotetishvili, 1995), Czech Republic (Vašiček & Summesberger, 2004), Bulgaria, Colombia (Hoedemaeker, 2004; Kakabadze, 2004), etc., the concept of an uppermost Barremian waagenoides Zone as proposed by Hoedemaeker & Rawson (2000) may be retained. However, at the 2nd International Meeting of the IUGS Lower Cretaceous Ammonite Working Group, the "Kilian Group" (Neuchâtel, Switzerland, 8 September 2005), Miguel Company and Gérard Delanoy objected that P. waagenoides occurs mainly in shallow shelf environments and is very rare in basins. Consequently it was proposed that the former Pseudocrioceras waagenoides Zone be lowered to the rank of a subzone, which corresponds to the uppermost part of the Martelites sarasini Zone.

On the other hand, there is a general agreement that places the lower limit of the Aptian in the Mediterranean area at the FAD of the genus Deshayesites s.s. (= bed 60 at Cassis-La Bédoule). In addition, this datum coincides with the disappearance of most of the heteromorphic ammonites with Barremian characters, such as the representatives of the genus Pseudocrioceras.

Paradeshayesites oglanlensis Zone (Fig. 2 ): Convincing arguments (Raisossadat, oral communication, 2002) were put forward at the 1st International Workshop of the IUGS Lower Cretaceous Ammonite Working Group ["Kilian Group"] (Lyon, 2002) for the use of Paradeshayesites oglanlensis Bogdanova, 1983, rather than Paradeshayesites tuarkyricus Bogdanova, 1983, as the index-species of the basal zone of the Aptian stage. P. oglanlensis has a wide geographic distribution, for it is found in SE France, Spain, Romania, Iran and the Transcaspian region, whereas P. tuarkyricus has been collected only in Turkmenistan and Iran (Kopet Dagh). Like Hoedemaeker & Reboulet (2003), Vašiček & Summesberger (2004), Barragán-Manzo & Méndez-Franco (2005), we have chosen to select P. oglanlensis as the index of the lowermost zone of the Aptian.

Paradeshayesites weissi Zone: According to Casey (personal communication, 2000) and to Bogdanova & Mikhailova (2004, p. 194) the term "weissi Zone" should be considered unacceptable, for P. weissi is a nomen dubium. The specimens figured by Neumayr & Uhlig (1881) and by Koenen (1902) are different and in any case the types are lost. Casey has not been able to trace any specimen in the German museums that could be designated as a neotype. For the time being we preserve the usual denomination until a new index, subject to general approval, is selected. Deshayesites consobrinus, chosen by Busnardo (1984), is a good candidate, for it is the index species for a sequence nearly equivalent to and including the range of Paradeshayesites weissi.

Deshayesites deshayesi Zone: In the Cassis-La Bédoule section, we have tentatively placed the base of the D. deshayesi Zone at bed 129, where we collected the first specimens of this index species. A hiatus may exist at this level (Moullade et alii, 2000c; Renard et alii, 2000). This hypothesis is based on 1) the sharp lithologic contrast between the underlying more calcareous Unit 3 and the overlying more marly Unit 4, 2) the thin yellowish crust that separates these units, interpreted as an indication of a hardground, 3) geochemical evidence. Such a gap might include part of the D. deshayesi and/or P. weissi zones.

In the middle part (bed 148-160) and the uppermost part (beds 160-169) of the D. deshayesi Zone we have segregated two horizons with, respectively, Roloboceras hambrovi and Paradeshayesites grandis as index-species.

Lower Aptian (Bedoulian) / Middle Aptian (Gargasian) boundary

In the Cassis-La Bédoule area the limit between these two Aptian substages was placed at the bed 170 by Fabre-Taxy et alii (1965), mainly because of a significant change between Units 5 and 6 in bedding geometry and rhythm, but also because of the occurrence in bed 170 of a specimen of Tropaeum bowerbanki. In 1994 Conte, having found representatives of Tropaeum and Dufrenoyia occurring together higher in the succession, proposed moving the boundary up to bed 178. This placement was adopted by Moullade et alii (1998) and is retained here. Above bed 178 we collected the typical pyritized Gargasian fauna with Aconeceras nisum, Gargasiceras sp., Colombiceras sp., and Cheloniceras (Epicheloniceras) martini (Conte & Ropolo, in press).

Systematic descriptions

Six sections in the vicinity of Roquefort-La Bédoule (Les Camerlots, Les Caniers, Highway A 52, Les Fourniers) and Cassis (Le Brigadan, Villeneuve-Comte Quarries) (Fig. 4 ) were investigated for this paper. The Deshayesitidae that we collected are assigned to the Paradeshayesites oglanlensis, P. weissi, Deshayesites deshayesi and Dufrenoyia furcata zones.

In the following tables we will use the standard abbreviations generally accepted for the main shell parameters:

D = maximum diameter
d = minimum diameter
Wh = whorl height
Uw = umbilical width
Wb = whorl breadth
(The ratio Wb/Wh expresses the degree of compression of the shell)
K = number of ribs per half whorl
Ph = diameter at the end of phragmocone
n = specimen entirely septate
(E) = Evolute morphotype
(I) = Involute morphotype
All measurement are in mm.

Material: Specimens from the Ropolo Collection are designated by numbers preceded by the mentions "ABR" or "BW". Conte's collection is labelled with a "C". The material from these two collections is deposited in the Museum of Paleontology, University of Provence, Campus Saint-Charles, Marseilles. The Gonnet Collection (Avignon) is labelled "RG".

Family Deshayesitidae Stoyanow, 1949

We use the generic terms (Deshayesites, Paradeshayesites and Dufrenoyia) as proposed by the Russian authors (Bogdanova & Mikhailova, 1999, 2004) in their recent revisions of the family.

1) Genus Deshayesites Kasansky, 1914

Type-species: Deshayesites deshayesi Leymerie in d'Orbigny, 1841, by original designation.

We refer to this genus 16 species collected in the Cassis-La Bédoule area:

• Deshayesites bedouliensis Cecca, Ropolo et Gonnet, 1999 (P. oglanlensis Zone)
• D. bogdanovae Avram, 1999 (P. weissi Zone)
• D. consobrinus (d'Orbigny, 1841) (P. weissi Zone)
• D. sp. aff. consobrinus (d'Orbigny, 1841) (P. oglanlensis Zone)
• D. dechyi Papp, 1907 (P. weissi Zone)
• D. deshayesi (Leymerie, 1841) (D. deshayesi Zone)
• D. euglyphus Casey, 1964 (P. weissi Zone)
• D. evolvens Luppov, 1952 (P. weissi Zone)
• D. forbesi Casey, 1961 (P. weissi Zone)
• D. formosus Bogdanova, Kvantaliani et Sharikadze, 1979 (D. deshayesi Zone)
• D. geniculatus Casey, 1964 (D. deshayesi Zone)
• D. cf. gracilis Casey, 1964 (P. oglanlensis Zone)
• D. luppovi Bogdanova, 1983 (P. oglanlensis Zone)
• D. planus Casey, 1964 (P. weissi Zone)
• D. sp. aff. rarecostatus Bogdanova, Kvantaliani et Sharikadze, 1979 (P. weissi Zone)
• D. gr. spathi/normani Casey, 1964 (P. weissi Zone).

Deshayesites bedouliensis Cecca, Ropolo et Gonnet, 1999
(Pl. 2 , figs. 1-2; Pl. 3 , figs. 2-3)

• 1999 Deshayesites bedouliensis Cecca, Ropolo et Gonnet, p. 270, Pl. 1, fig. 1; Pl. 2, fig. 1; Pl. 3, figs. 1- 2; Pl. 4, fig. 1; Pl. 5, figs. 1-2; Pl. 6, fig. 1; Pl. 7, fig. 1; Pl. 8, fig. 1.
• 2000 Deshayesites bedouliensis Cecca, Ropolo et Gonnet; Cecca, Ropolo & Gonnet, p. 150-151, Pl. 1 fig. 1.
• 2004 Deshayesites bedouliensis Cecca, Ropolo et Gonnet; Bogdanova & Mikhailova, p. 202.
• 2004 Deshayesites bedouliensis Cecca, Ropolo et Gonnet; Vašiček & Summesberger, p. 57, Pl. 2, fig. 1.

Material: BW 055 (holotype), BW 006, BW 014, BW 021, BW 052, BW 053, BW 054, BW 057, BW 058, BW 061, BW 062, BW 063, BW 067, BW 068, BW 071, BW 074, BW 075, BW112, BW270, RG 1456.

Description: Highly variable discoidal shells, with a large umbilicus. Morphotypes may be evolute or involute. On the phragmocone, ornamentation consists first of dense, numerous, thin, flexuous primary, secondary and intercalory ribs, separated by interspaces of equal width, but sculpture becomes increasingly strong on the body chamber where rib relief changes abruptly. There, the ribs become more distant, are bifurcate or often single. Generally, the point of branching is situated on the upper third of the flank. On the internal whorls, primary ribs spring from prominent periumbilical tubercles. On adult specimens, the last whorl usually touches the venter of the preceeding one. The section is subtrapezoidal. Some specimens have a rounded venter tending to flatten. The ornamentation of this species has a wide range of variability. The ribs can be rectiradiate, prorsiradiate or rursiradiate. The intercalatories can start at different heights. Sometimes two intercalated ribs are developed rather than one.

Measurements:

Discussion: Due its peculiar characteristics: densely ribbed internal whorls and substantial variability in coiling (the whorl-height decreases considerably and the whorl-breadth increases as the umbilicus widens), this taxon cannot be compared with any other occurring in the lowermost Aptian. For example, both Deshayesites consobrinus and Deshayesites sp. aff. consobrinus, have a more rapid growth of the whorls and a different ribbing. The involute specimens of Deshayesites bedouliensis in some respects resemble Paradeshayesites grandis. But in addition to the fact that the latter occurs at a higher level (D. deshayesi Zone, P. grandis Subzone), it differs in its stronger ribbing and in the numerous single ribs at the end of the growth. D. bedouliensis has also some similarity to the macroconchs of P. weissi, but this taxon has more inserted ribs and on the whole is more densely ribbed.

Occurrence: D. bedouliensis was described, figured and placed stratigraphically by Cecca et alii (1999, 2000). Because individual beds can be correlated in all the sections studied, we have used Moullade's bed numbering system (Moullade et alii, 2000b) to delimit its range. D. bedouliensis is the first Deshayesitidae encountered at la Bédoule (in beds 60/61 [= bed 82/83 of Cecca et alii, 1999] and in beds 62, 65, 69, 75 of Moullade's numbering, cf. Fig. 7 ). Paradeshayesites oglanlensis Zone, Le Brigadan, Les Camerlots, Les Caniers, Highway A 52 sections.

Distribution: We thought this species endemic, but recently it was found and collected in the lowermost Aptian of the Drôme department, SE France (Delanoy 2005, oral communication) and of Northern Austria. (Vašiček & Summesberger, 2004).

Deshayesites bogdanovae Avram, 1999
(Pl. 10 , fig. 7)

• 1979 Deshayesites consobrinus (d'Orbigny); Bogdanova, Pl. 2, figs. 3a-b & 4a-c.
• 1999 Deshayesites bogdanovae Avram, p. 452 & p. 455, fig. 8 A-C.

Material: 2 specimens: ABR149 and C526.

Description: Very similar to the ammonite represented by Avram, 1999 (p. 455, fig. 8A), this small evolute discoidal shell has a wide umbilicus, flat sides and dense sigmoidal ribbing. Intercalatories are short, branching at the middle flanks from the neighbouring primary rib. All the ribs are projected onto the ventral area. Section is high-oval with a rounded venter.

Measurements:

Discussion: The specimens attributed by Bogdanova (1979, Pl. 2, figs. 3-4) to Deshayesites consobrinus (d'Orbigny, 1841) cannot be matched with either the original illustration of d'Orbigny (1841) or the lectotype designated by Casey (1964, p. 352, fig. 124b), which is larger, with coarser ribs, much longer intercalatories and several consecutives primaries. Deshayesites bogdanovae Avram has a much denser ribbing and no consecutive primaries.

Occurrence: Paradeshayesites weissi Zone, Les Fourniers, bed 118.

Distribution: Lower Aptian (Paradeshayesites weissi Zone) of Turkmenistan, Dâmbovicioara Couloir (Romania), SE France.

Deshayesites consobrinus (d'Orbigny, 1841)
(Pl. 6 , figs. 1 & 6; Pl. 7 , fig. 5)

• 1841 Parahoplites consobrinus d'Orbigny, Pl. 47.
• 1915 Parahoplites weissi Neumayr et Uhlig; Kilian & Reboul, Pl. 3, fig. 3.
• 1915 Parahoplites consobrinus d'Orbigny; Kilian & Reboul, Pl. 4, fig. 6.
• non 1979 Deshayesites consobrinus (d'Orbigny); Bogdanova, p. 159-161, Pl. 2, figs. 3a-b (= D. kemperi Bogdanova et Mikhailova, 2004).
• non 1979 Deshayesites consobrinus (d'Orbigny); Bogdanova, p. 159, Pl. 2 figs. 4a-c [= D. bogdanovae Avram (1999)].
• 1999 Deshayesites consobrinus (d'Orbigny); Ropolo et alii, Pl. 19, fig. 1.
• 2000a Deshayesites consobrinus (d'Orbigny); Ropolo et alii, p. 163, figs. 1-4.
• 2004 Deshayesites consobrinus (d'Orbigny); Bogdanova & Mikhailova, p. 202, Pl. 4, figs. 1-3.

Material: 8 complete specimens: RG1571, RG1572, RG1579, RG1580; ABR319, BW076, BW077, SCP4.

Measurements:

Description: Discoidal, compressed shell with each whorl overlapping the upper third of the preceding whorl. The venter is convex, rounded sometimes wide. The flanks are flat or slightly convex. Ribs are first thin, s-shaped and slightly inclined forward. The young whorls show distant, strong, straight or gently flexuous primary ribs that spring from a very slight periumbilical thickening. In the adult whorls, the primary ribs become stronger, sometimes sharp, and prominent particularly in the lower third of the flank where they form slight distinct bullae. Intermediate ribs are often lacking on the body chamber of adult forms. On the venter all the ribs show an adoral convexity. On the last half whorl the number of ribs is from 18 to 20.

Discussion: Ammonites consobrinus d'Orbigny, common in SE France but rare in other regions, was chosen by Busnardo (1984) as the index-species of his Deshayesites consobrinus Zone. As an index-species D. consobrinus could replace Paradeshayesites weissi, which is a nomen dubium according to Casey (personal communication, 2000).

In the Les Fourniers and Les Caniers sections we collected several specimens in absolute conformity with d'Orbigny's original figure in "Paléontologie française" (1841). These specimens were described, placed and illustrated in a preceding paper (Ropolo et alii, 2000a).

Occurrence: Paradeshayesites weissi Zone, Lower Aptian, La Bédoule, Les Fourniers section; beds 114, 115, 116, 123, 125, 127.

Distribution: Paradeshayesites weissi Zone, Southern France; Paradeshayesites weissi and D. deshayesi? zones, Tuarkyr, Kubadag, Bolshoi Balkhan, Turkmenistan; D. forbesi Zone, D. fittoni Subzone; Southern England (under the name D. cf. consobrinus); D. dechyi Zone, Daghestan, Russia.

Deshayesites sp. aff. consobrinus (d'Orbigny, 1841)
(Pl. 3 , fig. 1)

• 1973 Deshayesites aff. consobrinus (d'Orbigny, 1841); Glazunova, p. 134, 135; Pl. 88, figs. 1a-c.
• 1999 Deshayesites aff. consobrinus (d'Orbigny, 1841); Cecca, Ropolo & Gonnet, p. 280, Pl. 9, fig. 1.

Material: One complete specimen (BW 066), numerous fragments.

Description: This taxon presents many similarities with an ammonite figured by Glazunova (1973, Pl. 88, figs. 1a-c) collected in the Volga region. Our specimen is an evolute, discoidal shell with an ovate compressed whorl section. On the body chamber, relatively strong, rounded single ribs are separated by an intercalatory which appears, a little above or a little below mid-flank. Then primaries become biplicate on the lower half of the flank. A complete description of this ammonite is given in Cecca et alii (1999).

Measurements:

Discussion: This form differs from Deshayesites consobrinus (sensu stricto) in its high and steep umbilical wall and more numerous ribs. It differs too from the Turkmenian ammonites described by Bogdanova (1979, Pl. 2, figs. 3-4) under the name Deshayesites consobrinus (=Deshayesites bogdanovae Avram, 1999) which bear more flexuous and numerous (27/28) ribs per half-whorl (rather than 22/23) and has a more evolute coiling.

Occurrence: P. oglanlensis Zone, Le Brigadan, Les Caniers, beds 62, 70, 74, 84.

Distribution: Lower Aptian of the Volga region (Russia), La Bédoule (SE France: P. oglanlensis Zone).

Deshayesites dechyi (Papp, 1907)
(Pl. 4 , fig. 3; Pl. 5 , fig. 2; Pl. 8 , fig. 1)

• 1907 Parahoplites dechyi nov. sp., Papp, p. 171, Pl. 9, figs. 3 & 5 (non 1-2 & 4)
• 1926 Deshayesites dechyi (Papp); Renngarten, p. 30, Pl. 2, figs. 11-12; Pl. 9, fig. 6
• 1952 Deshayesites cf. dechyi (Papp); Luppov, p. 204, Pl. 7, figs. 1-2
• 1977 Deshayesites dechyi (Papp); Bogdanova, p. 50, Pl. 2, figs. 1-5
• 1979 Deshayesites dechyi (Papp); Bogdanova, p. 5, Pl. 1, figs. 1-5
• 1999 Deshayesites dechyi (Papp, 1907); Bogdanova, Pl. 2, figs. 3-4
• 1999 Deshayesites dechyi (Papp, 1907); Bogdanova & Prozorovsky, Pl. 4, fig. h.
• 1999 Deshayesites dechyi (Papp, 1907); Conte, p. 12, fig. 2b.
• 2004 Deshayesites dechyi (Papp, 1907); Bogdanova & Mikhailova, p. 203, Pl. 3, figs. 6 & ?8; text-fig. 9.
• 2004 Deshayesites dechyi (Papp, 1907); Raisossadat, p. 129, figs. 4 M-N.

Material: 6 specimens: ABR220, ABR14, ABR214, ABR46, ABR502, ABR510, and several fragments.

Measurements:

Description: Of medium size, with a subrectangular whorl section, Deshayesites dechyi is a moderately involute ammonite, with a sigmoidal ribbing that consists of primary and intermediate ribs. Between every two main ribs are intercalated one or two secondary ribs branching between the lower third and the middle of the flank. All ribs are slightly flattened on the venter and form a sinus forward.

Discussion: D. dechyi presents many similarities in rib pattern with D. forbesi Casey, but that species is more involute and has stronger ribs displayed as a constant alternation of primary and intercalatory ribs.

Occurrence: Paradeshayesites weissi Zone, Lower Aptian, Deshayesites deshayesi Zone, Cassis-La Bédoule: beds 125, 127 of Les Fourniers section, bed 138c of Comte quarry section.

Distribution: Lower Aptian, D. dechyi/deshayesi Zone of North Caucasus, Daghestan (Russia) and Romania; D. weissi/D. deshayesi Zone of Turkmenistan and SE France; Lower Aptian ("plita") of Mangyshlak (Kazakhstan); Lower Aptian of Kopet Dagh Basin (Iran).

Deshayesites cf. dechyi (Papp, 1907)
(Pl. 7 , fig. 3)

Material: One complete specimen (ABR501), one fragment (C003) and one incomplete specimen (C033).

Measurements:

Description: Of medium size, this ammonite is more involute than Deshayesites dechyi and has sigmoidal bifurcate and trifurcate ribs branching at the mid-flank. As in D. deshayesi, the primary ribs start from the umbilical wall but become stronger on the siphonal area. The umbilical width is about a quarter of the total diameter.

Discussion: Ribs are as strong as in Deshayesites euglyphus Casey, but less regular and are not bent forward in a shallow arc on the venter. The poor preservation of our specimen does not permit a better comparison of this form with the typical Deshayesites dechyi.

Occurrence: Beds 137, 138c, D. deshayesi Zone, Les Fourniers section.

Deshayesites deshayesi (Leymerie, 1841)
(Pl. 10 , figs. 1-2)

• 1841 Ammonites Deshayesi Leymerie; d'Orbigny, Pl. 85, figs. 1-4.
• 1907 Hoplites (Parahoplites) Deshayesi Leymerie; Jacob, p. 46, fig. 28.
• 1938 Parahoplites (Parahoplitoides) deshayesi Leymerie; Roman, p. 350, fig. 326.
• 1957 Deshayesites deshayesi (Leymerie); Wright, p. L 387, fig. 505.
• 1964 Deshayesites deshayesi (Leymerie); Casey, p. 295, Pl. 43, fig. 3; text-fig. 106.
• 1973 Deshayesites deshayesi (Leymerie); Glazunova, p. 120, Pl. 76, fig. 1.
• 1977 Deshayesites deshayesi (Leymerie); Bogdanova, p. 55, Pl. 3, fig. 6.
• 1979 Deshayesites deshayesi (Leymerie); Bogdanova, Pl. 2, fig. 6.
• 1999 Deshayesites deshayesi (Leymerie); Bogdanova & Prozorovsky, p. 78, Pl. 7, figs. b & e-f.
• 2004 Deshayesites deshayesi (Leymerie); Bogdanova & Mikhailova, Pl. 4, figs. 6-7.
• 2004 Deshayesites deshayesi (Leymerie); Raisossadat, p. 130, figs. 5 D-E & H-I.

Material: 2 complete specimens: ABR511, ABR512, and several fragments

Measurements:

Description: Shells of medium size with nearly parallel sides and a slightly flattened venter. Although somewhat crushed, our specimens conform to the figuration of Casey (1964, text-fig. 106) with sigmoidal, sharp and strong ribs. Primary ribs start from the upper part of the umbilical wall and are directed forward forming a gentle sigmoidal curve. Intermediate ribs are intercalated between main ribs. Between each pair of primaries, there is only one secondary, branching between the mid-flank and the outer third.

Discussion: Deshayesites deshayesi (Leymerie) presents some similarities with D. forbesi Casey, in the regular alternation of long and short ribs. But D. forbesi is generally evolute, the ribbing is denser and more regular, the umbilical wall is oblique, and the sides are more rounded.

Occurrence: Beds 129a & b, 135, 150 of Comte Quarry section, D. deshayesi Zone.

Distribution: Lower Aptian (D. deshayesi Zone) of England, North Germany, Bulgary, SE France (La Bédoule), Turkmenistan; Lower Aptian of Daghestan (Russia), Mangyshlak (Kazakhstan), Kopet Dagh (NE Iran).

Deshayesites euglyphus Casey, 1964
(Pl. 5 , fig. 5; Pl. 6 , fig. 7)

• 1964 Deshayesites euglyphus Casey, p. 336-338; Pl. 52, figs. 1-4; Pl. 56, figs. 1 a-b.
• 1999 Deshayesites euglyphus Casey; Bogdanova, Pl. 2, fig. 7.
• 1999 Deshayesites euglyphus Casey; Bogdanova and Prozorovsky, Pl. 4, figs. a, d & f.

Material: 2 specimens: ABR490, ABR500.

Measurements:

Description: Ammonite moderately evolute, with a subrectangular whorl section; flanks slightly rounded. The ribbing, very regular, consists of strong, sigmoidal, rounded primary ribs starting from the umbilical wall and intercalated secondary ribs branching from a little below to a little above mid flank.

Discussion: As noted by Casey (1964), the inner whorls, uniformly costate, are similar to those of Deshayesites kiliani Spath, 1930. But the umbilicus is wider and there are fewer secondary ribs. Variability is very high in this species and in private collections we have observed many forms transitional between D. kiliani and D. gr. spathi/normani, which also present certain characters of Deshayesites euglyphus.

Occurrence: Beds 112, 120 Les Fourniers section, P. weissi Zone.

Distribution: D. forbesi Zone of England; D. weissi Zone, Turkmenistan; Lower Aptian ("plita") of Mangyshlak (Kazakhstan), Iran, SE France.

Deshayesites evolvens Luppov, 1952
(Pl. 5 , fig. 4; Pl. 8 , fig. 2)

• 1952 Deshayesites evolvens nov. sp. Luppov, p. 205, Pl. 8, fig. 1.
• 1967 Deshayesites evolvens Luppov; Dimitrova, p. 184, Pl. 91, fig. 1.
• 1995 Deshayesites aff. evolvens Luppov; Delanoy, Pl. 3, fig. 1.
• 1999 Deshayesites evolvens Luppov; Ropolo et alii, Pl. 19, fig. 3.
• 1999 Deshayesites cf. evolvens Luppov; Conte, p. 13, figs. 3a-b.

Material: 2 specimens: PR/Abm311 (mould), ABR489 (incomplete specimen); RG1577 (this one slightly crushed).

Measurements:

Description: Discoidal ammonite with flat or slightly convex flanks. On the inner whorl ornamentation consists of relatively strong and flexuous ribs, proverse forward and starting from the inside of the umbilical wall. These ribs (24 by half whorl) are bifurcate, or more rarely, trifurcate at mid-flank. On the body chamber the ribbing changes. Ribs become stronger, straight and simple. Intermediate ribs disappear progressively and only single, distant ribs subsist by the aperture. Our specimens correspond to Luppov's original illustration (1952, Pl. 8, fig. 1).

Discussion: This species presents many affinities with an ammonite figured by Kilian & Reboul (1915, Pl. 3, fig. 3) under the name Parahoplites weissi (Neumayr et Uhlig) which, according to Luppov (1952), must be referred to Deshayesites evolvens.

Occurrence: Les Fourniers section, beds 115, 119, P. weissi Zone.

Distribution: Lower Aptian of Turkmenistan (Deshayesites Zone in Luppov, 1952); Lower Aptian of Bulgaria, NE Caucasus (Russia) and Mangyshlak (Kazakhstan); P. weissi Zone in SE France.

Deshayesites forbesi Casey, 1961
(Pl. 6 , figs. 2-4; Pl. 7 , fig. 4)

• 1961 Deshayesites forbesi Casey, p. 593, Pl. 81, figs. 2a-b.
• 1964 Deshayesites forbesi Casey; Casey, p. 314, Pl. 47, figs. 1a-b & 2-7; text-figs. 104g, 106i & 110a.
• 1999 Deshayesites forbesi Casey; Avram, p. 449, figs. 6 F-H.
• 2004 Deshayesites forbesi Casey; Bogdanova & Mikhailova, Pl. 3, fig. 4.

Material: Two fragments ABR42a & b, and 3 incomplete specimens: ABR47, ABR318, ABR333.

Measurements:

Description: Our specimens are assigned to Casey's species, because of their oblique umbilical wall and similar ornamentation. Ribbing consists of bifurcate slightly sinusoidal primary ribs branching at the lower third of the flank. All the ribs project forward on the venter.

Discussion: This species presents a high degree of variability so four varieties were formally named by Casey (1964): Deshayesites forbesi forbesi, D. forbesi var. koenini, D. forbesi var. flexuosus, D. forbesi var. crassicostatus and, according to the author (1964, p. 319), there are many other transitional forms related to the typical one.

Occurrence: Beds 117, 126, Comte Quarry section.

Distribution: D. forbesi Zone of England, P. weissi Zone in SE France, D. deshayesi Zone of Bulgaria.

Deshayesites formosus Bogdanova, Kvantaliani et Sharikadze, 1979

• 1979 D. formosus Bogdanova, Kvantaliani et Sharikadze; Pl. 4, figs. 1-6.
• 1999 D. formosus Bogdanova, Kvantaliani et Sharikadze; Bogdanova & Mikhailova, p. 526.

Material: One specimen (ABR503).

Measurements:

Description: Evolute ammonite with flat and sub-parallel sides. On the inner whorls ribs are sinusoidal with secondaries branching at mid-flank. In early whorls one or two intermediate ribs alternate regularly with primaries branching from them at the first third of the flank. On the body chamber, ribs can be single and become stronger and more widely spaced with growth.

Discussion: D. formosus presents some similarities with D. consobrinus but differs from it by having more bifurcations on the ribs which biplicate or sometimes triplicate on the main whorls.

Occurrence: Bed 120, P. weissi Zone, Comte quarry section.

Distribution: D. dechyi-D. deshayesi Zone of Daghestan (Russia), P. weissi Zone in SE France.

Deshayesites geniculatus Casey, 1964
(Pl. 10 , fig. 6)

• 1961 Deshayesites sp. nov. Casey, p. 510, p. 609.
• 1964 Deshayesites geniculatus sp. nov., Casey, p. 307, Pl. 46, figs. 5a-b; Pl. 51, figs. 9a-b.
• 1999 Deshayesites geniculatus Casey; Bogdanova & Mikhailova, p. 526.

Material: One incomplete specimen (ABR508).

Measurements:

Description: Evolute ammonitewith a high rounded subrectangular whorl section. Ribs are strong, flexuous, prorsiradiate, primaries rising from the mid-height of the umbilical wall. There are one, sometimes two, intercalatories branched from the neighbouring primary rib. Some intercalatory ribs appear at the upper third of the flank. About 20 ribs per half whorl.

Discussion: Our specimen clearly resembles that figured by Casey (1964, Pl. 46, fig. 5a). But its ribbing is less regular and ribs seem more numerous. It shows some similarities with Deshayesites punfieldensis Spath, but in that species ribs curve more strongly and the interval between two ribs is larger.

Occurrence: Bed 166, Comte Quarry section, D. deshayesi Zone (P. grandis Subzone).

Distribution: D. deshayesi Zone (P. grandis Subzone) of southern England; D. deshayesi Zone (P. grandis Sub-Zone) of SE France.

Deshayesites cf. gracilis Casey, 1964
(Pl. 10 , fig. 4)

• 1964 Deshayesites gracilis sp. nov., Casey, p. 324, Pl. 47, fig. 10.
• 2004 Deshayesites gracilis Casey; Bogdanova & Mikhailova, p. 207, Pl. 6 figs. 5-6; text-fig. 13.

Material: One specimen (ABR336).

Measurements:

Description: Shell moderately involute, with flat sides. The umbilical area occupies one third of the diameter and bears tubercles. Ribs are narrow, weakly sigmoidal and inclined forward (about 30 per half whorl). The main ribs start from the upper part of the umbilical wall. One or two secondary ribs are intercalated between each pair of main ribs starting at the inner third of the flank.

Discussion: Our specimen shows a denser ribbing than that of the typical form. It presents some similarities with D. involutus var. hytensis Casey, but this variety has a narrower umbilicus and shorter secondary ribs, starting just above mid-flank, some of them fusing with adjacent main ribs. It can also be confused with D. callidiscus Casey but the ribbing of this taxon is denser and flexuosity of its ribs is more accentuated.

Occurrence: Bed 159, Comte Quarry section, D. deshayesi Zone (R. hambrovi Subzone).

Distribution: Lower Aptian (Crackers Beds) of South England; P. weissi Zone of Turkmenistan; D. deshayesi Zone of Bulgaria, SE France.

Deshayesites luppovi Bogdanova, 1983
(Pl. 1 , figs. 1-2, 4 & 12)

• 1952 Deshayesites aff. dechyi Papp; Luppov, p. 203, Pl. 7, fig. 1.
• 1983 Deshayesites luppovi Bogdanova, p. 139, Pl. 3, figs. 1-6
• 1999 Deshayesites luppovi Bogdanova; Avram, p. 447, figs. 5 f-g.
• 1999 Deshayesites luppovi Bogdanova; Bogdanova, Pl. 1, fig. 10.
• 1999 Deshayesites luppovi Bogdanova; Bogdanova & Prozorovsky, Pl. 3, fig. f.
• 1999 Deshayesites luppovi Bogdanova; Ropolo et alii, p. 178, Pl. 16, figs. 4-5.
• 2004 Deshayesites luppovi Bogdanova; Raisossadat, p. 125, Figs. 5 A, C & L.
• 2004 Deshayesites luppovi Bogdanova; Bogdanova & Mikhailova; p. 207, Pl. 2, figs. 8-9; text-fig. 14.

Material: 12 specimens: ABR32, ABR36, ABR279, ABR285, ABR2168, ABR2169, ABR2172, ABR2173, ABR2174, ABR2177, ABR1285, ABR4601.

Measurements:

Description: Small, moderately involute shells, with nearly flat flanks, narrow and rounded venter. Umbilicus is about one third of the diameter. The ribbing is very sinuous with sigmoidal primaries arched forward near the middle part of the flanks; one or two secondaries frequently bifurcate or trifurcate from primaries. Secondaries are variable in length; the point of union with primaries may be well above mid-flank (bifurcate ribs), or well below (trifurcate ribs). Sometimes primaries form peri-umbilical bullae and broaden out strongly before branching.

Discussion: Our specimens are comparable in rib pattern and umbilicus width with those figured by Bogdanova & Mikhailova (2004, figs. 8-9). The coiling of D. luppovi is slightly more evolute than that of Paradeshayesites oglanlensis; ribs are stronger and more flexuous.

Occurrence: P. oglanlensis Zone, beds 61, 63, 65, 72,78, 88, 101. Le Brigadan, Les Caniers, Highway A52, Les Camerlots sections.

Distribution: Paradeshayesites tuarkyricus and P. weissi zones of Turkmenistan; P. oglanlensis Zone of SE France, Spain, Romania; Lower Aptian ("plita") of Mangyschlak (Kazakhstan), Iran.

Deshayesites sp. aff. luppovi Bogdanova, 1983
(Pl. 4 , fig. 1)

Material: One complete specimen (ABR279).

Measurements:

Description: Large involute shell, moderately evolute on the last whorl, with flat or slightly convex flanks, narrow and rounded venter, numerous and sinuous ribs on the juvenil whorls, starting as a kind of tubercle on the umbilical wall. The primary ribs are separated by one or two secondary ribs either branching on mid-flank or single. On the body chamber, all ribs become stronger, prominent, and intercalatory often separated from the neighbouring primary rib. All ribs cross the venter without interruption and show a gentle adoral convexity.

Discussion: Because of the great similarity of the ribbing pattern with Deshayesites luppovi, we think that this specimen could be a macroconch of this species. The distant and strong ribbing on the last whorl and the high and steep umbilical wall on the body chamber separate this specimen from those included in D. bedouliensis, which is characterized by a finer and weaker ribbing.

Occurrence: Bed 72, Le Brigadan Section (P. oglanlensis Zone).

Deshayesites planus Casey, 1964
(Pl. 5 , fig. 3)

• 1961 Deshayesites planus Casey, p. 609.
• 1964 Deshayesites planus Casey, p. 323, Pl. 57, fig. 5; text-figs. 112a-b & e.
• 1977 Deshayesites planus Casey; Bogdanova, p. 52, Pl. 3, figs. 1-5; Pl. 4, figs. 7-8; text-figs. 4a-b.
• 1999 Deshayesites planus Casey; Avram, p. 445, figs. 5c-e.
• 1999 Deshayesites planus Casey; Bogdanova & Prozorovsky, Pl. 4, figs. g & ?i.

Material: Two complete specimens: ABR321, ABR339, and several fragments of spire.

Measurements:

Description: Small moderately evolute shell with flat sides. Our specimens are conformable with the holotype figured by Casey (1964, Pl. 57, fig. 5). Primary ribs start from the upper part of the umbilical wall. At mid-flank, these main ribs biplicate or triplicate in short secondary ribs intercalated between two primaries. All ribs form a sigmoidal curve on the flanks.

Discussion: We found many fragments of this species in the weissi Zone but only two specimens were complete. The umbilicus seems to be larger than that of Casey's type.

Occurrence: Bed 116, Comte Quarry section, P. weissi Zone.

Distribution: D. forbesi Zone of England (callidiscus Subzone), P. weissi Zone of Turkmenistan and SE France, Lower Aptian of Bulgaria.

Deshayesites cf. planus Casey, 1964
(Pl. 9 , fig. 3)

Material: One specimen ABR362.

Measurements:

Description: Involute crushed ammonite, with a ribbing pattern similar to that of Deshayesites planus but the ribs are more numerous and more flexuous. On the umbilical wall the main ribs start forming a kind of bundle. At mid-flank, they become very sinuous and bifurcate or trifurcate. About 34 ribs by half whorl. Umbilicus very narrow.

Discussion: This ammonite differs from Deshayesites cf. planus described and illustrated by Raisossadat (2004, p. 130, figs. 5 J-K) by a less regular, denser and more sinuous ribbing. Intermediate ribs start commonly from the upper third of the flank.

Occurrence: Bed 122, Les Fourniers Section, P. weissi Zone.

Distribution: P. weissi Zone of SE France.

Deshayesites sp. aff. rarecostatus Bogdanova, Kvantaliani et Sharikadze, 1979

• 1979 Deshayesites rarecostatus Bogdanova, Kvantaliani et Sharikadze, p. 526, Pl. 3, figs. 1-4.

Material: A fragment of whorl; specimen C031.

Description: The fragment mentioned above is half a whorl of an evolute shell of about 45 mm diameter. The ribs are exceptionally strong (about 22 by half whorl), biplicate and spring from the upper part of the umbilical wall, with their point of branching located just below or just above mid-flank. Sometimes intercalate ribs are single.

Discussion: Because its sculpture corresponds to that of the specimens illustrated in Bogdanova et alii (1979, Pl. 3, figs. 1-4), we relate with doubt this fragment to D. rarecostatus. However, more and better preserved material is needed to clarify the taxonomic status of this form.

Occurrence: Bed 137, Comte Quarry section, P. deshayesi Zone.

Distribution: Deshayesites dechyi/deshayesi Zone of Daghestan; D. deshayesi Zone of SE France (La Bédoule).

Deshayesites sp. gr. spathi Casey, 1964/normani Casey, 1964
(Pl. 5 , fig. 1; Pl. 8 , fig. 3; Pl. 9 , fig. 1)

• 1930 Deshayesites Spath, p. 430.
• 1964 Deshayesites spathi, Casey, p. 332, Pl. LI, fig. 2; Pl. LII, figs. 5a-b & 6; text-figs. 116e & 117.
• cf. 1964 Deshayesites normani, Casey, p. 344, text-fig. 121; Pl. 50, fig. 7; Pl. 54, figs. 1a-b; Pl. 55, figs. 3-4; Pl. 56, figs. 3a-b.
• 1995 Deshayesites gr. spathi/normani Casey; Delanoy, p. 82, Pl. 1 fig. 2.
• 1999 Deshayesites spathi Casey; Ropolo et alii, Pl. 18, fig. 4.
• 2000 Deshayesites aff. normani Casey; Gonnet et alii, Pl. 2, fig. 5; Pl. 7, fig. 2

Material: Two well preserved specimens and a very large ammonite with sculpture only partly visible: ABR323, ABR340; ABG342.

Measurements:

Description: This species has a rounded venter and a thick robust ribbing. Primaries, first prominent and then spatulate, start from the umbilical margin and bifurcate or trifurcate at the inner third of the flank but sometimes remain single on the body chamber in adult specimens (ABG342). All ribs form a feebly sigmoidal curve at mid-flank and become thinner on the upper part of the side. Secondaries are irregularly intercalated between main ribs.

Discussion: Deshayesites spathi Casey, 1964 and D. normani Casey, 1964, both common ammonites of the D. forbesi Zone in England, have a "similar type of ribbing" (Casey 1964, p. 345); so it is often difficult to distinguish between them and they are often confused. As they occur in the same levels we are led to think that these two forms could be morphologic variants of a single species. This seems to be the opinion of Russian authors too because in the "species composition" of the genus Deshayesites in Bogdanova & Mikhailova, 1999 (p. 523-526), D. spathi is not mentioned.

Occurrence: Beds 111, 114, 126, Les Fourniers section, P. weissi Zone.

Distribution: D. forbesi Zone of England; P. weissi Zone of SE France (La Bédoule) and Turkmenistan.

2) Genus: Paradeshayesites Kemper, 1967

Type-species: Hoplites laeviusculus Koenen, 1902; Lower Aptian, tenuicostatus Zone, Northern Germany.

We include in this genus 7 species collected in the several sections studied at Cassis-La Bédoule:

• Paradeshayesites callidiscus var. rugosus (Casey, 1961),
• Paradeshayesites grandis (Spath, 1930),
• Paradeshayesites cf. involutus (Spath, 1930),
• Paradeshayesites oglanlensis (Bogdanova, 1983),
• Paradeshayesites planicostatus (Bogdanova, 1991),
• Paradeshayesites weissi (Neumayr et Uhlig, 1881),
• Paradeshayesites weissiformis (Bogdanova, 1983).

Paradeshayesites callidiscus Casey 1961, var. rugosus Casey 1964
(Pl. 4 , fig. 2; Pl. 7 , fig. 1)

• 1964 Deshayesites callidiscus Casey, var. rugosus nov., Casey, p. 329, Pl. 49, figs. 5a-b; Pl. 56, figs. 5a-b.
• 1999 Deshayesites callidiscus Casey; Ropolo et alii, Pl. 19, fig. 2.
• 2000 Deshayesites callidiscus Casey; Gonnet et alii, Pl. 6, fig. 3.

Material: ABR43, ABR188, ABR317, ABR388, ABR337; RG1576. Numerous fragments.

Measurements:

Description: This taxon is well represented in the P. weissi Zone of the Cassis-La Bédoule area. Shells of medium to large size, with flat sides, venter rounded and weakly convex. Some specimens are compressed (ABR43). The umbilical width is about one quarter of the diameter. 26 sigmoidal ribs per half-whorl. Sigmoidal primaries start from the umbilical wall, first thin on the first third of flank, then becoming stronger and flat topped. They bifurcate at mid-flank, where short intercalatories are inserted. All ribs are separated by very narrow interspaces and cross the venter, forming a sinus towards the aperture.

Discussion: We refer our specimens to Deshayesites callidiscus Casey, var. rugosus Casey because their ornamentation somewhat resembles that of the ammonite illustrated by the author (Pl. 56, figs. 5a-b).They differ slightly from the typical forms which have more numerous and more flexuous ribs and a "fasciculate" type of ribbing.

Occurrence: Beds 110, 113, 119, Les Fourniers section, P. weissi Zone.

Distribution: D. forbesi Zone of England; P. weissi Zone of SE France (La Bédoule)

Paradeshayesites grandis (Spath, 1930)
(Pl. 10 , figs. 3 & 5; Pl. 11 , fig. 1)

• 1930 Deshayesites grandis Spath; pp. 427-9 (pars), Pl. 17, figs. 2a-b.
• 1964 Deshayesites grandis Spath; Casey, p. 308-310, Pl. XLIII, figs. 1a-b; Pl. XLIV, figs. 1-3; Pl. LI, figs. 7a-b; text-fig. 110c.

Material: 5 specimens: ABR360, ABR347, ABR348, ABR352, ABR354, and many fragments.

Measurements:

Description: Highly variable ammonite with more or less involute shells. Casey (1964) figured large specimens of Deshayesites grandis which are either evolute (Pl. XLIII, figs. 1a-b) or involute (Pl. XLIV, figs. 1-2). The sculpture consists of gently flexuous or straight ribs starting from the vertical umbilical wall and intercalatories branching at mid-flank. Some primaries bifurcate or trifurcate on the first third of the side. Interspaces are very narrow. The ribbing is generally strong and there are sometimes numerous single ribs at the end of the growth. Sides are flat or gently convex. The poor preservation of our specimens, which are incomplete or cannot be extracted from the gangue, does not permit a more exact study of the shell section.

Discussion: Our specimens range in diameter from 27,2 (microconch?) to 169 (macroconch ?) mm. To a degree several fragments resemble extreme forms of Dufrenoyia gr. truncata/discoidalis Casey or Dufrenoyia transitoria Casey. However, Paradeshayesites grandis has denser ribbing and a well rounded venter, while in Dufrenoyia the ribs form nodes or ventrolateral shoulders on the venter which is always narrow and flattened.

Occurrence: Beds 161a, 164, 166, Comte Quarry section, D. deshayesi Zone, P. grandis Subzone.

Distribution: D. deshayesi Zone, P. grandis Subzone of England, Cassis-La Bédoule (SE France).

Paradeshayesites cf. involutus (Spath, 1930)
(Pl. 9 , fig. 2; Pl. 12 , fig. 1)

• cf. 1930 Deshayesites consobrinus (d'Orbigny) var. involuta Spath, p. 432.
• cf. 1964 Deshayesites involutus Spath; Casey, p. 310, Pl. 45, figs. 1a-c; text-fig. 107.
• 1964 Deshayesites cf. involutus Spath; Casey, p. 310, Pl. 45, figs. 4a-b.
• 1999 Deshayesites cf. involutus Spath; Avram, p. 454, fig. 8d.
• 2004 Deshayesites cf. involutus (Spath); Raisossadat, p. 129, figs. 6A-C.

Material: Two specimens (a small incomplete juvenile specimen and a large adult shell with poorly preserved sculpture): ABG325, ABG329, and numerous fragments.

Measurements:

Description: Moderately involute ammonites with a wide umbilicus (about one-third of the diameter), vertical umbilical wall and rounded venter. Ornamentation consists of straight primary ribs and short secondaries often irregularly branched on main ribs at mid-flank or on the upper part of the side. Some intercalatories are single, others bifurcate or trifurcate. Ribs can be radial on the body chamber or weakly sigmoidal.

Discussion: Our juvenile specimen shows similarities in the rib pattern with Paradeshayesites cf. involutus (Spath) illustrated by Casey (1964, Pl. 45, figs. 4a-b). The adult specimen could be confused with the Lower Bedoulian species Deshayesites consobrinus, but its umbilicus is wider than that of the d'Orbigny's species and this specimen was collected in the Upper Bedoulian P. grandis Sub-Zone, with two fragments of the same species.

Occurrence: Beds 165, 168. Comte Quarry section, D. deshayesi Zone, P. grandis Subzone.

Distribution: D. deshayesi Zone, P. grandis Subzone of England, Cassis-La Bédoule (SE France).

Paradeshayesites oglanlensis (Bogdanova, 1979)
(Pl. 1 , figs. 3, 11 & 13)

• 1979 Deshayesites oglanlensis Bogdanova; p. 153, Pl. 2, figs. 5a-5b [nomen nudum].
• 1983 Deshayesites oglanlensis Bogdanova; p. 136, Pl. 1, figs. 5-9; text-figs. 5-6.
• 1995 Deshayesites oglanlensis Bogdanova; Delanoy, p. 74, Pl. 2, figs. 1 a-b.
• 1997 Deshayesites oglanlensis Bogdanova; Aguado et alii, fig. 7 e.
• 1999 Deshayesites oglanlensis Bogdanova; Ropolo et alii, p. 278, Pl. 17, fig. 2 (non fig. 1).
• 1999 Deshayesites oglanlensis Bogdanova; Bogdanova & Prozorovsky, Pl. 3, figs. d-e.
• 1999 Deshayesites oglanlensis Bogdanova; Cecca et alii, p. 278, Pl. 1, figs. 2-4.
• 2000 Deshayesites oglanlensis Bogdanova; Gonnet et alii, Pl. 1, fig. 2; Pl. 2, fig. 4 (non Pl. 1, fig. 1).
• 2004 Deshayesites oglanlensis Bogdanova; Raisossadat, p. 123, Pl. 4, figs. G-H.
• 2004 Paradeshayesites oglanlensis (Bogdanova); Bogdanova & Mikhailova, p. 214, Pl. 7, fig. 4

Material: 9 specimens: BW002, BW004, BW007, BW011a, BW021, BW050, ABR271, ABR281, ABR30.

Measurements:

Description: Shell of medium to large size (20 to 190 mm diameter) with rounded-subrectangular, a relatively wide umbilicus, and flat or gently rounded flanks. All the specimens exhibit the ornamentation typical of the species: thin, flexuous, fasciculate ribs on the initial and intermediate stage, developed from peri-umbilical bullae. Basically, the ribs have are sinusoidal, inclined forward (proverse ribs), towards the aperture. They often bifurcate on the upper part of the flanks and form a sinus on the ventral part. On the adult stage they broaden out and become strong and radial.

Discussion: It is not always easy to identify Paradeshayesites oglanlensis with certainty. Most Deshayesitidae of the tuarkyricus Zone, with the exception, perhaps, of D. sp. aff. consobrinus, are very densely ribbed, particularly on the phragmocone, and each rib is a sigmoidal curve of varying flexuosity. However, our specimens are similar in form and in sculpture to those illustrated by Bogdanova (1979, Pl. 2, figs. 5a-b; 1983, Pl. 1, figs. 1-9.).

Occurrence: Beds 62, 63, 78, 103, 105, La Bédoule (Les Caniers, Les Camerlots, Le Brigadan, Highway A52 sections), P. oglanlensis Zone.

Distribution: P. tuarkyricus Zone of Turkmenistan and Mangyshlak; P. oglanlensis Zone of SE France, Iran (Kopet-Dag).

Paradeshayesites sp. aff. planicostatus (Bogdanova, 1991)
(Pl. 1 , figs. 7-8 & 10)

• aff. 1991 Deshayesites planicostatus Bogdanova, p. 80, Pl. 2, figs. 1-3; text-fig. 2.
• aff. 1999 Deshayesites planicostatus Bogdanova; Avram p. 447, fig. 6A (only).
• aff. 1999 Deshayesites cf. planicostatus Bogdanova; Cecca et alii, p. 279, Pl. 7, fig. 3.
• aff. 2004 Paradeshayesites planicostatus Bogdanova; Bogdanova & Mikhailova, p. 214, Pl. 7, figs. 5-6; text-fig. 24.

Material: 4 complete specimens: ABR301, ABR33, ABR282, BW05, and several fragments of whorl.

Measurements:

Description: Small, moderately evolute ammonite, with flat or subparallel sides. The ribs are flexuous, simple or biplicate, branching between the middle and the upper third of the flank. These ribs start from bullae located on the periumbilical edge. Primaries and secondaries are slightly thickened and very strongly flattened on the upper part of the side. All are sigmoidal and describe a convexity towards the aperture across the venter.

Discussion: Our material shows most of the characters of the species, such as an angular umbilical margin, flat and curved ribs, umbilical bullae, but in ABR33 the umbilical width is less and the base of the sculpture is erased in several places on the sides. On ABR301, ribs are radial on the body chamber, not sinusoidal as in the type.

Occurrence: Beds 63, 67, 82, 86, La Bédoule (Les Caniers, Les Camerlots, and les Fourniers sections), P. oglanlensis Zone, Lower Aptian.

Distribution: P. tuarkyricus and P. weissi zones of Turkmenistan; Lower Aptian of Romania and P. oglanlensis Zone of SE France.

Paradeshayesites weissi (Neumayr et Uhlig, 1881)
(Pl. 4 , fig. 4; Pl. 6 , figs. 5 & 8; Pl. 7 , fig. 2)

• 1881 Hoplites weissi nov. sp. Neumayr et Uhlig, p. 179, Pl. XLVI, figs. 1 & 1a; Pl. 47, fig. 1.
• 1902 Hoplites weissi Neumayr et Uhlig; Koenen, p. 207, Pl. XLV, fig. 1.
• 1907 Hoplites cf. weissi Neumayr et Uhlig; Karakasch, p. 92, Pl. XI, fig. 2.
• non 1915 Parahoplites weissi (Neumayr et Uhlig), Kilian & Reboul, Pl. III, fig. 3; Pl. IV, fig. 4; Pl. VI, fig. 2
• 1964 Deshayesites weissi (Neumayr et Uhlig); Casey, text-figs. 108 & 109a.
• non 1967 Deshayesites weissi (Neumayr et Uhlig); Dimitrova, p. 183, Pl. 88, fig. 7.
• 1977 Deshayesites weissi (Neumayr et Uhlig); Bogdanova, p. 47, Pl. I, fig. 4; Pl. IV, fig. 6; text-fig. 2.
• 1977 Deshayesites planus Casey; Bogdanova; Pl. III, figs. 4 a-b (only).
• 1995 ? Deshayesites aff. callidiscus Casey; Delanoy, Pl. 1, fig. 1.
• 1999 Deshayesites weissi (Neumayr et Uhlig); Avram, p. 442, figs. 2 A-C.
• 1999 Deshayesites weissi (Neumayr et Uhlig); Bogdanova & Prozorovsky, p. 73, Pl. 4, figs. b-c.
• 2004 Deshayesites weissi (Neumayr et Uhlig); Raisossadat, p. 127, fig. 4L.

Material: 6 complete specimens: RG1575, ABR29, ABR289, ABR187, ABR320, ABR016, one incomlete specimen: ABR50, and numerous fragments of whorls.

Measurements:

Description: Medium to small moderately involute shells, with a very steep umbilical wall, rounded venter and an umbilicus measuring between one third and one quarter of the total diameter, flanks sub-parallel. Sculpture consists of dense and thin sigmoidal ribs starting from the umbilical wall. They bifurcate at one third to half way up the sides. Some intermediate ribs can be intercalated between two main ribs at various heights on the flanks.

Discussion: We relate our specimens to the Neumayr & Uhlig's species because in many respects they resemble the ammonite illustrated by Bogdanova & Prozorovsky (1999, Pl. 4, figs. b-c). As reported by Raissosadat (2004), in small specimens the ribbing is denser than in the larger ones.

Occurrence: Beds 110, 113, 115, 118, 120, Les Fourniers section, Paradeshayesites weissi Zone.

Distribution: P. weissi Zone of SE France, NW Germany, Turkmenistan; P. weissi/albrechti-austriae Zone of the Northern Caucasus; Lower Aptian of the Ulyanovsk region (Russia) and Lower Aptian of Bulgaria.

Paradeshayesites weissiformis (Bogdanova, 1983)
(Pl. 1 , figs. 5-6; Pl. 2 , fig. 3)

• 1983 Deshayesites weissiformis Bogdanova, p. 134, Pl. 2, figs. 1-3; Pl. 3, fig. 7; text-figs. 3-4.
• 1995 Deshayesites weissiformis Bogdanova; Delanoy, p. 74, Pl. 5, fig. 2.
• 1999 Deshayesites weissiformis Bogdanova; Ropolo et alii, p. 179, Pl. 18, fig. 3.
• 1999 Deshayesites weissiformis Bogdanova; Cecca et alii, p. 278, Pl. 6, figs. 2-3.
• 1999 Deshayesites weissiformis Bogdanova; Avram, p. 440, figs. 3A & E.
• 2004 Deshayesites cf. weissiformis Bogdanova; Raissosadat, p. 124, fig. 4J.
• 2004 Paradeshayesites weissiformis Bogdanova; Bogdanova & Mikhailova, p. 212, Pl. 7, fig. 3; text-fig. 21.

Material: 8 specimens: BW003, BW022, ABR272, ABR278, ABR37, ABR38, ABR40, ABR143 (Ropolo Collection) and numerous fragments of whorl.

Measurements:

Description: Involute, discoidal shells with subparallel sides and rounded venter. Very steep umbilical wall. The dense ornamentation is rather irregular and consists of sinuous biplicate ribs and intercalatories starting from the lower fourth of the flank. The umbilical margin bears tubercles from which originate the sinusoidal main ribs. The point of branching of the biplicate ribs lies slightly above the mid-flank.

Discussion: Some specimens are compressed and broken. Others are well preserved. Because of similarities in sculpture, a relatively narrow umbilicus and morphologic resemblance, we include these ammonites in the group of Paradeshayesites weissiformis Bogdanova. However, they differ from the holotype in having a stronger and more flexuous ribbing.

Occurrence: Beds 64, 79, 80, 82, 106, 109, La Bédoule (Le Brigadan, Les Caniers, Highway A52, Les Camerlots sections), Paradeshayesites oglanlensis Zone.

Distribution: P. tuarkyricus Zone of Turkmenistan; P. oglanlensis Zone of SE France; Lower Aptian of Mangyshlak (Kazakhstan), Kopet-Dag (Iran).

3) Genus: Dufrenoyia Kilian et Reboul, 1915

We include in this genus 10 species of ammonites with calcareous test collected in the Comte Quarry section from bed 171 to bed 178:

• Dufrenoyia furcata (Sowerby, 1836),
• Dufrenoyia dufrenoyi (d'Orbigny, 1841),
• Dufrenoyia formosa Casey, 1964,
• Dufrenoyia fursovae Bogdanova, 1991,
• Dufrenoyia mackesoni Casey, 1964,
• Dufrenoyia notha Casey, 1964,
• Dufrenoyia sinzovi Luppov, 1949,
• Dufrenoyia sp. gr. transitoria/discoidalis Casey, 1964,
• Dufrenoyia truncata Spath, 1930,
• Dufrenoyia sp.

Dufrenoyia furcata (J. de C. Sowerby, 1836)
(Pl. 12 , fig. 3; Pl. 13 , fig. 1)

• 1836 Ammonites furcatus J. de C. Sowerby (in Fitton), p. 339, Pl. XIV, fig. 17.
• 1915 Parahoplites (Dufrenoyia) furcatus (Sow.); Kilian & Reboul, p. 34, text-fig. 4.
• 1925 Dufrenoyia furcata (Sowerby); Burckhardt, p. 17, Pl. X, figs. 12-13.
• non 1960 Dufrenoyia furcata (Sowerby); Drushchits, p. 312, Pl. I (Part. 2), figs. 7 a-b.
• 1964 Dufrenoyia furcata (Sowerby); Casey, p. 378, text-figs. 135-136; Pl. 62, figs. 2-3; Pl. 63, fig. 1; Pl. 64, figs. 1a-1b.
• 1999 Dufrenoyia furcata (Sowerby); Bogdanova, p. 353, Pl. II, figs. 8a-b; Pl. III, figs. 1a-b.
• 1999 Dufrenoyia furcata (Sowerby); Bogdanova & Prozorovsky, Pl. 8, figs. d?e.
• 2003 Dufrenoyia furcata (Sowerby); Ropolo & Gonnet, p. 24, Pl. 1, figs. 1-9.
• 2004 Dufrenoyia furcata (Sowerby); Bogdanova & Mikhailova, p. 219, Pl. 12, figs. 1-3; text-fig. 28.

Material: 4 calcareous specimens: ABR1425; C1426, C1428, C1429.

Measurements:

Description: Small to medium sized discoidal shells, involute, with coarse ribbing, flat and angular venter, and moderately wide umbilicus. Ribs first broaden and then become spatulate on the upper part of the flanks and are terminated by clavi at the ventro-lateral shoulders. Sculpture (12/13 ribs by half whorl) consists of robust and slightly flexuous primaries, their inflexion directed forward, sometimes more prominent at the base of the flanks; intercalatories originate at the first third of the side. Occasionally secondaries show bifurcation with the primaries, thus forming a two branched fork.

Discussion: This species, which was often not recognized as discrete from Dufrenoyia dufrenoyi (d'Orbigny) by French authors like Roch (1927, p. 19), Thomel (1980, p. 135) and Atrops & Dutour (2002, p. 23), differs from d'Orbigny's in that it has fewer ribs per half whorl (12/13, not 16 to 18) and consequently the ribs are coarser and farther apart. On the young whorls costulation is more radial and less flexuous. D. furcata is morphologically very close to D. lurensis Kilian, but the latter has a more inflated shell and a more robust ribbing.

It is clear from our investigations in SE France that the biochron of D. furcata corresponds to the lower part of the Dufrenoyia interval and differs from that of Dufrenoyia dufrenoyi, which first appears later than D. furcata and has a longer stratigraphic range (cf. also Dutour, in press). Despite early attempts at clarification (e.g. Casey, 1964, p. 382), confusion over the identification of the two species and the existence of two stratigraphical concepts (the D. furcata Zone and the vertical range of the genus Dufrenoyia) gave rise to controversy about the precise location of the upper limit of the Lower Aptian in SE France.

Occurrence: Beds 171, 172, 173, 174, 176, Comte Quarry section, D. furcata Zone.

Distribution: D. furcata Zone of southeastern France; T. bowerbanki Zone of England; D. furcata Zone of Turkmenistan; D. furcata/D. subfurcata Zone of the Northern Caucasus (Russia); Lower Aptian of Mangyshlak (Kazakhstan).

Dufrenoyia dufrenoyi (d'Orbigny, 1840)
(Pl. 12 , fig. 2; Pl. 13 , fig. 2)

• 1840 Ammonites dufrenoyi d'Orbigny, p. 200, Pl. 33, figs. 3-5.
• 1841 Ammonites dufrenoyi d'Orbigny, p. 200, Pl. 33, figs. 4-6.
• 1849 Ammonites dufrenoyi d'Orbigny; Quenstedt, p. 158, Pl. 10, fig. 10.
• 1897 Hoplites dufrenoyi (d'Orbigny); Sarasin, p. 769, fig. 6.
• 1960 Dufrenoyia furcata (Sowerby); Drushchits, Pl. XXII, figs. 7a-b.
• 1961 Dufrenoyia dufrenoyi (d'Orbigny); Eristavi, p. 52, Pl. II, fig. 2.
• 1964 Dufrenoyia dufrenoyi (d'Orbigny); Casey, p. 375, text-figs. 134 a & c.
• 1980 Dufrenoyia furcata (Sowerby); Thomel, p. 135, fig. 268.
• 1999 Dufrenoyia dufrenoyi (d'Orbigny); Bogdanova p. 353, Pl. III, figs. 2a-b.
• 1999 Dufrenoyia dufrenoyi (d'Orbigny); Bogdanova & Prozorovsky, Pl. 8, figs. a-c.
• 2003 Dufrenoyia dufrenoyi (d'Orbigny); Ropolo & Gonnet, p. 26, Pl. 1, figs. 10-12; Pl. 2, figs. 1-6.
• 2004 Dufrenoyia dufrenoyi (d'Orbigny); Bogdanova & Mikhailova, p. 219, Pl. 12, figs. 7-9.

Lectotype: Designated by Bogdanova & Mikhailova (2004) ex d'Orbigny (1841), "Paléontologie française", Pl. 33, figs. 4-5.

Material: 4 specimens: ABR332; C1456, C1458, C1459.

Measurements:

Description: Moderately evolute shell, trapezoidal in section, flat and angular venter with subangular margins, flat or gently convex sides. Ribs (16 per half whorl) radial, straight or slightly sinusoidal, ending on the venter in rounded clavi. Primaries and secondaries alternate regularly. Primaries start from the umbilical wall. Secondaries originate at the middle or at the first third of flank. All ribs tend to broaden and flatten as they approach the venter. As in Dufrenoyia furcata, the ribs seem sometimes to bifurcate at different height on the young whorls.

Discussion: Two illustrations of this species were published by d'Orbigny, as mentioned by Bogdanova & Mikhailova (2004). The first one, in the first issue of "Paléontologie française" (1840, Pl. 33, figs. 3-5) (cf. Fig. 5  of this paper), represents an ammonite with thick whorls and relatively widely spaced ribs (16 by half whorl). The second is the figure included in the definitive edition (1841, Pl. 33, figs. 4-6); better known, this figure differs notably from the earlier illustration: narrower and higher whorls, more numerous and denser ribs (20 per half whorl). In his monograph on the Lower Greensand, Casey (1964, p. 375, text-figs. 134 a-c) cited only the second figure and apparently considered it the sole valid one. We think that both morphotypes are conspecific and have found them in the same levels in SE France where specimens resembling the first figure are more common.

According to Atrops & Dutour (2005) and Dutour (in press), in SE France this species appears after Dufrenoyia furcata and becomes extinct later. We agree with this later extinction of D. dufrenoyi, even though its range cannot be directly confirmed in the Cassis-La Bédoule area, where the Bedoulian-Gargasian transition is condensed and is now poorly exposed (Moullade et alii, 2005); but our investigations in the Aptian type-area of Gargas (near Apt, SE France) (Ropolo & Moullade, 2002) as well as in the Vocontian Basin, have determined that its paracme may coincide with the FAD of Acanthoplites aschiltaensis; indeed, in the Gargasian of Lioux and Carniol (respectively located 10 km NW and 20 km NE of Apt) we have collected several specimens of A. aschiltaensis occurring together with D. dufrenoyi.

Occurrence: Beds 173, 175, 176, Comte Quarry section, D. furcata Zone.

Distribution: D. furcata Zone (and basal Gargasian) of southeastern France; D. furcata Zone, Turkmenistan; Lower Aptian ("plita") of Mangyschlak (Kazakhstan); Lower Aptian of Mexico.

Dufrenoyia formosa Casey, 1964

• 1964 Dufrenoyia formosa nov. sp. Casey, pp. 395, Pl. LXIII, fig. 3; Pl. LXV, fig. 3; Pl. LXVI, figs. 4-5.
• 1976 Dufrenoyia formosa Casey; Peybernès, p. 280, Pl. XXV, figs. 3-4.
• 2003 Dufrenoyia formosa Casey; Ropolo & Gonnet, p. 34; Pl. 5, figs. 1-4.

Material: Two calcareous specimens: C1432, C1501.

Measurements:

Description: Discoidal and moderatly evolute shell with a subelliptical whorl section, wider at the first third of flanks. Ribbing (18 ribs by half whorl) consists of radial or feebly sinusoidal primaries, and shorter secondaries originating from from the first third of the flank. The ventral area is flat and smooth, edged by marginal clavi which terminate each rib. On juvenile whorls it is sometimes possible to distinguish bundles of two, three or four flexuous ribs or a succession of bifurcated ribs fusing at mid flank.

Discussion: The nuclei of Dufrenoyia formosa can show a succession of bifurcated ribs as in one (Pl. LXV, fig. 3) of the specimens illustrated by Casey, 1964. Generally, primaries and secondaries are not in contact.

Occurrence: Bed 175, Comte Quarry section, D. furcata Zone.

Distribution: T. bowerbanki Zone of England, Lower Aptian of Ramade (Western Pyrénées, SW France), D. furcata Zone of Cassis La Bédoule, Aptian marls of the Vocontian Basin and of the type-region of Gargas (SE France).

Dufrenoyia fursovae Bogdanova, 1991
(Pl. 10 , fig. 8; Pl. 13 , fig. 3)

• 1991 Dufrenoyia fursovae Bogdanova, p. 88, Pl. 2, figs. 9-11; text-fig. 6.
• 1999 Dufrenoyia fursovae Bogdanova; Bogdanova, p. 352, Pl. II, figs. 10a-b.
• 1999 Dufrenoyia fursovae Bogdanova; Bogdanova & Prozorovsky, p. 80, Pl. 8, fig. g
• 2003 Dufrenoyia fursovae Bogdanova; Ropolo & Gonnet; p. 31, Pl. 5, figs. 9-11.
• 2004 Dufrenoyia fursovae Bogdanova; Bogdanova & Mikhailova, p. 220, Pl. 12, fig. 10; text-fig. 29.

Material: 3 complete calcareous specimens on gangue: ABR602 a & b, C1503; one incomplete spire: C604; plus 3 fragments (Conte collection).

Measurements:

Description: Small, moderately involute ammonite, with a subelliptical whorl section and slightly convex flanks. Ribbing very dense, with 28 ribs by half whorl. The sculpture consists of long sinusoidal primaries starting from the umbilical wall and shorter secondaries appearing sometimes at the first third of the flank, and even sometimes at mid flank. Venter flat and smooth, with thin marginal tubercles lengthening each rib. This species has usually two secondaries between neighbouring main ribs.

Discussion: Dufrenoyia fursovae Bogdanova resembles D. sinzovi Luppov but its ribbing is denser and more flexuous. Intermediaries are often single or in pairs and never join the primary ribs.

Occurrence: Bed 171, Comte Quarry section, D. furcata Zone.

Distribution: D. furcata Zone of Turkmenistan, Lower Aptian of Mangyshlak, D. furcata Zone of Cassis-La Bédoule (SE France).

Dufrenoyia mackesoni Casey, 1964
(Pl. 13 , figs. 7-8)

• 1964 Dufrenoyia mackesoni Casey, p. 397, Pl. LXIII, figs 5a-b; Pl. LXV, figs. 4a-b; text-figs. 140d-144.
• 2003 Dufrenoyia mackesoni Casey; Ropolo & Gonnet, p. 36, Pl. 4, figs. 7-11.

Material: Two calcareous specimens: C611, C612.

Measurements:

Description: Small to medium-sized moderately evolute shell, with slightly convex flanks and a subrectangular whorl section. Angular to subangular venter bordered by weak marginal clavi. The costation of moderate relief consists of a regular alternation of primaries starting from the umbilical wall and secondaries originating at mid flank. Primaries tend to flatten on the upper third of the flank. All ribs are falciform. According to Casey (1964), the interspaces are a little wider than the ribs.

Discussion: Our specimens are very similar to the holotype, Pl. LXV, figs. 4a-b, in Casey, 1964. Under the designation "Dufrenoyia cf. mackesoni" this author describes and illustrates (p. 398, text-fig. 144) a calcareous adult specimen from La Bédoule (La Sorbonne collections). This very evolute ammonite has a diameter of 115 mm, a wider umbilicus (= half total diameter instead of one third) and more numerous (20/21 instead of 18) ribs per half whorl than our specimens.

Occurrence: Beds 171, 173, 176, Comte Quarry section, D. furcata Zone.

Distribution: T. bowerbanki Zone of England, D. furcata Zone of Cassis-La Bédoule, Aptian marls of the Vocontian Basin and of the type-region of Gargas, Lioux, La Tuilière (SE France).

Dufrenoyia notha Casey, 1964
(Pl. 12 , fig. 4; Pl. 14 , fig. 7)

• 1930 Dufrenoyia furcata (J. de C. Sowerby); Spath, p. 435-436 (pars).
• 1964 Dufrenoyia notha Casey; p. 386, Pl. LXIII, figs. 8a-b; Pl. LXIV, figs. 5a-b; text-fig. 140 j.
• 2003 Dufrenoyia notha Casey; Ropolo & Gonnet, p. 30, Pl. 3, figs. 6-11.

Material: 5 specimens: ABR333, ABR1431, ABR1433, ABR1434, ABR1435.

Measurements:

Description: Small to medium-sized discoidal and evolute shell. In the juvenile stage the whorl section is subtrapezoidal with slightly rounded flanks. In the adult stage the whorl section becomes progressively subrectangular. The ornamentation (14 ribs by half whorl) shows in alternation long radial primaries starting from the periumbilical wall, and shorter intermediate ribs originating from the first third of the flank. On the juvenile whorls ribs occasionally have an incipient bifurcation and become gently sinuous. All ribs run straight over the venter, forming parallel marginal clavi on both sides.

Discussion: Dufrenoyia notha Casey shows some similarities with D. furcata (Sowerby). However, the latter is more involute and has ribs more widely spaced and more forked, as well as more angular margins on the venter area.

Occurrence: Beds 172, 173, 174, 176, Comte Quarry section, D. furcata Zone.

Distribution: T. bowerbanki Zone of England, D. furcata Zone of southeastern France.

Dufrenoyia sinzovi Luppov, 1949
(Pl. 13 , fig. 4)

• 1949 Dufrenoyia sinzovi sp. Luppov, p. 228, Pl. 66, figs. 1a-b.
• 1999 Dufrenoyia sinzovi, Luppov; Bogdanova & Prozorovsky, p. 80, Pl. 8, figs. f & h-i.
• 2003 Dufrenoyia sinzowi Luppov; Ropolo & Gonnet, p. 32, Pl. 2, figs. 4-8.

Material: A fragment of whorl (C649)

Measurements:

Description: We have attributed to Luppov's species a fragmentary whorl with a costulation similar to that of the type. Dense sinusoidal ribbing, alternation of primaries starting from the umbilical area and intercalatories originating at the first third of the flank. Ventro-lateral clavi are indistinct.

Discussion: This taxon is a typical Mediterranean ammonite, never found in the Boreal Realm.

Occurrence: Bed 174, Comte Quarry section, D. furcata Zone.

Distribution: D. furcata Zone of Turkmenistan, Lower Aptian of the Volga region (Russia), D. furcata Zone of southeastern France.

Dufrenoyia sp. gr. transitoria Casey, 1961/discoidalis Casey, 1964
(Pl. 13 , figs. 5-6)

• 1961 Dufrenoyia transitoria sp. nov., Casey, p. 594, Pl. 83, figs. 3a-b.
• 1964 Dufrenoyia discoidalis sp. nov., Casey, p. 393, Pl. LXVI, figs. 7-8; text-fig. 140g.

Material: One complete specimen C658, one fragment of whorl C662

Measurements:

Description: Small to medium-sized discoidal and evolute amonite with a subrectangular whorl section. Sides gently convex. Sculpture consisting of sigmoidal primary ribs starting from a vertical umbilical wall and tending to flatten on the uppermost part of the flanks, and flexuous secondaries originating more or less at the mid flank or in the first third of the flank. Some of these secondaries are unite with the primaries. All ribs are separated by narrow interspaces. They terminata in pronounced ventral clavi joined by bar-like swellings on the flat venter. The umbilicus size is one third of the total diameter.

Discussion: In England and in SE France this group seems to characterize the basal part of the respective zones (T. bowerbanki and D. furcata).

Occurrence: Beds 171, 173, Comte Quarry section, D. furcata Zone.

Distribution: T. bowerbanki Zone (D. transitoria Subzone) of England, D. furcata Zone (lower part) of Cassis-La Bédoule and of southeastern France.

Dufrenoyia truncata Spath, 1930
(Pl. 14 , figs. 1-3)

• 1930 Dufrenoyia truncata Spath, pp. 436, Pl. XVI, figs. 4b-c.
• 1964 Dufrenoyia truncata Spath, Casey, p. 392, Pl. LXII, figs. 1a-b; Pl. LXIII, figs. 4 & 7a-b; text fig. 140f.

Material: 3 calcareous specimens: C660, C668, C669.

Measurements:

Description: Small to medium-sized discoidal and evolute ammonite, similar to Dufrenoyia transitoria in ribbing pattern, with sinusoidal primaries starting from the umbilical wall and secondaries originating from mid flank. However, in D. truncata the interspaces are wider, the ribs are less numerous (20 per half whorl), the periumbilical area is less angular and flanks are gently convex.

Discussion: Dufrenoyia truncata is often difficult to differentiate from D. transitoria from which, according to Casey (1964, p. 392), it differs only "in its slightly coarser ribbing".

Occurrence: Beds 174, 176, Comte Quarry section, D. furcata Zone.

Distribution: T. bowerbanki Zone (D. transitoria Subzone) of England, D. furcata Zone of Cassis-La Bédoule.

Dufrenoyia sp.
(Pl. 14 , fig. 5)

Material: One complete specimen (C1590) and several fragments.

Measurements:

Description: Small involute ammonite with radial ribs and rounded venter on the body chamber, dense sigmoidal ribs and flat venter on juvenile whorl. Primaries start from a vertical umbilical wall. Intercalatories, often single, take originate either from mid flank or from the first third of the flank.

Discussion: This ammonite is probably a crushed juvenile specimen and has a close resemblance to Deshayesites. But taking into account its flat venter, even though partly visible, and the level where it was collected, we refer it to the genus Dufrenoyia.

Occurrence: Beds 174-176, Comte Quarry section, D. furcata Zone.

Distribution: D. furcata Zone of Cassis-La Bédoule.

Summary and discussion of the main biostratigraphic results

Updating the paleontological study of the Cassis-La Bédoule area allowed us to determine more precisely the stratigraphic distribution of Uppermost Barremian/Lower Aptian ammonite assemblages in the historical stratotype. In every section examined we recorded bed by bed the succession of populations and therefore were able to record faunal changes step by step. In particular we collected in place and thus re-located the standard stratigraphic markers commonly accepted for use in the Tethyan Realm. These additional data are of major importance for the definition of biostratons and confirm our previously proposed stratigraphic scheme (Ropolo et alii, 2000b).

In the uppermost part (beds 45 – 60) of the Barremian stage, the abundance of heteromorphic ammonites of the genus Pseudocrioceras characterizes the P. waagenoides Zone (or Subzone). Never in these beds nor in overlying and underlying strata did we find specimens of Turkmeniceras sensu stricto Conversely, as yet no specimens of Pseudocrioceras have been reported in the Turkmeniceras levels of Turkmenistan. However, according to Delanoy (oral communication, 2005) Turkmeniceras occur at Angles, Barrême, and Vergons (Vocontian basin, SE France) in layers overlying the first occurrence of the genus Deshayesites (about 3-4 meters above the "faisceau épais"). Delanoy also found a unique specimen of Turkmeniceras in a condensed level in the Nice area. Nevertheless, as the exact stratigraphic position of this genus remains uncertain in SE France, it is not possible at this time to recognize a Turkmeniceras turkmenicum Zone in this region. In any event, we consider Pseudocrioceras waagenoides a more appropriate index for defining the terminal Barremian Zone (or Subzone) and consequently the Barremian/Aptian boundary.

From bed 61 to bed 178, the Deshayesitidae represent the dominant family among the ammonite groups that characterize the Lower Aptian deposits of Cassis-La Bédoule. Four biozones are defined by the successive first appearances of the following index species: Paradeshayesites oglanlensis, Paradeshayesites weissi, Deshayesites deshayesi, and Dufrenoyia furcata. These biozones take into account the evolution of the genera Paradeshayesites, Deshayesites and Dufrenoyia and their relationships with the other ammonite assemblages. In the historical stratotype they allow the recognition of chronostratigraphic subdivisions which now conform more exactly with the current Mediterranean standard scheme and so make correlations with other regions of the world easier.

Beds 61-109: Paradeshayesites oglanlensis Zone: The assemblage from this zone is represented successively by: Deshayesites bedouliensis Cecca, Ropolo et Gonnet, 1999, Paradeshayesites oglanlensis (Bogdanova, 1983), Paradeshayesites planicostatus (Bogdanova, 1991), Paradeshayesites weissiformis (Bogdanova, 1983), D. luppovi Bogdanova 1983, D. aff. consobrinus (d'Orbigny, 1841), D. cf. luppovi Bogdanova 1983, Paradeshayesites cf. weissiformis (Bogdanova, 1983), Paradeshayesites aff. weissiformis (Bogdanova, 1983), Paradeshayesites aff. planicostatus (Bogdanova, 1991).

Beds 110-128: Paradeshayesites weissi Zone: In this interval we collected: Paradeshayesites weissi (Neumayr et Uhlig, 1881), Paradeshayesites callidiscus var. rugosus (Casey, 1961), Deshayesites gr. spathi/normani Casey, 1964, D. consobrinus (d'Orbigny, 1841), D. gr. spathi/normani, D. forbesi Casey, 1961, D. bogdanovae Avram, 1999, D. evolvens Luppov, 1952, D. formosus Casey, 1964, D. euglyphus Casey, 1964, D. cf. planus, Casey, 1964, D. dechyi Papp, 1907, D. cf. dechyi Papp, 1907.

Beds 129-148: Deshayesites deshayesi Zone (lower part): Deshayesites deshayesi (Leymerie, 1841), D. cf. dechyi Papp, 1907, D. rarecostatus Bogdanova, Kvantaliani et Sharikadze, 1979.

Beds 149–160: Deshayesites deshayesi Zone, R. hambrovi Subzone: D. cf. gracilis Casey, 1964 (and numerous Roloboceras gr. hambrovi/transiens, Megatyloceras gr. coronatum/ricordeanum).

Beds 161-170 Deshayesites deshayesi Zone, Paradeshayesites grandis Subzone: Paradeshayesites grandis (Spath, 1930), P. cf. involutus (Spath, 1930), P. geniculatus Casey, 1964.

Beds 171-178 Dufrenoyia furcata Zone: Dufrenoyia furcata (Sowerby, 1836) D. fursovae Bogdanova, 1991, D. dufrenoyi (d'Orbigny, 1840), D. notha Casey, 1964, D. sinzovi Luppov, 1949, D. truncata Casey, D. formosa Casey, 1964, D. mackesoni Casey, 1964.

The boundaries of the D. furcata zone at Cassis-La Bédoule were defined on:

• the first occurrence of Dufrenoyia furcata sensu stricto for the lower boundary,
• the first occurrence of the pyritized Aconeceras nisus / Epicheloniceras martini assemblage for the upper boundary, which coincides with the lower limit of the Middle Aptian (Gargasian).

The micropaleontological revision of Moullade et alii (2005) of the Gargasian series in the Cassis area showed that several benthic foraminiferal species (Praedorothia praeoxycona, Lenticulina cf. nodosa, Astacolus crepidularis, Globorotalites bartensteini) as well as an ostracode (Protocythere bedoulensis) become extinct at or very near the top of the Bedoulian, while two planktonic species (Praehedbergella luterbacheri, and Globigerinelloides ferreolensis) first appear respectively near and slightly above the Bedoulian/Gargasian boundary. These data, which will be confirmed at La Tuilière in the Aptian historical stratotypic area (Moullade et alii, in prep.), do not contradict, but even strengthen the choice of placing the Bedoulian-Gargasian boundary at the top of the D. furcata Zone (bed 178 in the Bedoulian stratotype) as initially proposed by Conte (1994) and reaffirmed in this paper.

Some authors (Atrops & Dutour, 2002) are of the opinion that the ammonite fauna of the Dufrenoyia furcata Zone has more affinities with that of the Middle Aptian Subnodosocostatum Zone than with the Bedoulian forms and suggest that the Bedoulian/Gargasian boundary be placed at the top of the Deshayesites deshayesi Zone, i.e. at the base of the Dufrenoyia furcata Zone ["À Gargas, et dans les localités voisines de Carniol, de Simiane et d'Oppedette, la très abondante faune d'ammonites provient de la base du Gargasien, selon son acception originelle (Kilian, Jacob). Il s'agit du Gargasien inférieur (zone à Aconeceras nisus et Dufrenoyia furcata = dufrenoyi) (…)".

"(…) En outre, d'après nos récoltes, il apparaît clairement que le genre Dufrenoyia se poursuit jusque dans la Zone à Subnodosocostatum (…)"

" (…) Pour toutes ces raisons, nous pensons que la limite Bédoulien/Gargasien doit désormais être placée entre les zones à Deshayesi et à Furcata, cette dernière étant réintégrée à la base du Gargasien qui retrouve ainsi son acception première." (Atrops & Dutour, 2002, p. 23)].

We believe that this proposal is based on the misidentification of two discrete species, Dufrenoyia furcata (Sowerby) and D. dufrenoyi (d'Orbigny). We have shown above that: 
1) these taxa are morphologically distinct and differ in their stratigraphic ranges 
2) the duration of the D. furcata Zone and the stratigraphic range of the genus Dufrenoyia do not coincide, the latter being longer than the biochron of the index-species.

There are fundamental differences between the D. furcata Zone of Cassis-La Bédoule as defined and the marly levels containing specimens of Dufrenoyia in the type-locality of Gargas (near Apt, SE France) and nearby tracts (for example several outcrops at La Tuilière, near Saint-Saturnin-les-Apt), or in several sections of the Vocontian Basin. At Cassis-La Bédoule all the fossils from this zone are calcareous shells, collected painstakingly in well-defined alternating marly limestones and calcareous beds; all the Dufrenoyia found in the Apt-Gargas area and in the Vocontian Basin are pyritized ammonite nuclei, collected more or less haphazardly in a homogeneous marly sequence, in which a precise stratigraphic assignment is often difficult. Furthermore, at Cassis-La Bédoule the index-ammonite occurs in calcareous beds along with Tropaeum bowerbanki, a boreal form which characterizes the upper part of the Lower Aptian in Southern England. To our knowledge Tropaeum has not been found in the marls of the Apt area or in the Vocontian Basin. The Dufrenoyia associated with Tropaeum bowerbanki mentioned in literature are generally assigned a Lower Aptian age (Casey, 1961, p. 496-497; 1980, p. 637; Egoian, 1969, p. 127; Kemper, 1971, p. 364; Bogdanova, 1978, p. 78; Kakabadze et alii, 1978, p. 81; Kakabadze, 1981, p. 154; Kemper, 1982, p. 24; Mikhailova, 1983, p. 321; Bogdanova & Tovbina, 1994, p. 55; Baraboshkin & Mikhailova, 2002, Pl. 3, fig. 4; Bogdanova & Mikhailova, 2004, p. 195). Moreover, in the succession from bed 171 to bed 178 in Cassis-La Bédoule, we found no Aconeceras nisus, which first appears only above bed 178. In the Apt-Gargas area, this species co-occurs with Dufrenoyia. Thorough investigations in both sectors show that the vertical range of Dufrenoyia furcata is restricted to the basal part of the range of the genus Dufrenoyia. Other species of this genus, such as D. dufrenoyi (d'Orbigny, 1840), D. notha Casey, 1964, D. truncata Casey, 1964, etc. lived longer.

According to the rules of the International Stratigraphic Commission, it is not necessary that the biochron of an ammonite-index coincides precisely with the duration of the eponymous Zone. The Lower/Middle Aptian boundary was commonly placed at the first occurrence of Epicheloniceras subnodosocostatum (Conte, 1985; Kotetishvili, 1986; Hoedemaeker & Bulot, 1990; Bogdanova & Tovbina, 1994; Bogdanova & Prozorovsky, 1999, Hoedemaeker & Rawson, 2000). It appears that this taxon and/or other species of this genus may briefly co-occur with Dufrenoyia (Dutour, in press).

The D. furcata Zone of Cassis-La Bédoule and in general of SE France is correlated with the Furcata Zone of the Trans-Caspian regions (Resolution of Samarkand, 1977), the Furcata Zone of Turkmenia (Bogdanova 1978), the Furcata/Subfurcata Zone of Northern Caucasus (Drushchits et alii, 1986; Kotetishvili, 1986), the Bowerbanki Zone of England (Casey, 1961, 1998), the Dufrenoyia justinae Zone of Northeast Mexico (Barragán-Manzo & Mendes-Franco, 2005), and the Lower Aptian of Mangyshlak (Bogdanova, 1999). All these zones are assigned a Lower Aptian age. That this biostratigraphic entity be considered Middle-Aptian, as suggested by Atrops & Dutour (2002) and Dutour (in press), would introduce inconsistencies among these well-established correlations.

However, given the present state of our knowledge a problem seems to exist, because the genus Dufrenoyia appear to have a longer vertical range in SE France than in other Mediterranean areas. This anomaly might be due mainly to the higher rate of sedimentation in the marly sequence that comprises the Bedoulian-Gargasian transition in the Aptian historical stratotypes; this increase in rate is documented by the distribution of microfossils (Moullade et alii, 2000c, 2005).

The definition of stratigraphic subdivisions such as stages is somewhat conventionalized, if not even artificial, and this is even more true of substages. Historically, their limits have been based most often on faunal or facies changes believed to be well-marked. Zones and horizons are commonly delimited by the first occurrence of an index species or sometimes by the co-occurrence of an association of species. These subdivisions are accepted according to their ease of use and the possibilities they offer for correlation between discrete geographic areas. To avoid the incidence of too many misinterpretations and ambiguities, it is preferable to maintain a relative stability in stratigraphic nomenclature rather than to change the limits continually because of taxonomic changes and/or the discovery of new fossils. Historically, in the Lower Aptian stratotype the Bedoulian-Gargasian boundary has been founded on changes in facies and fauna believed to be sharply demarcated and simultaneous (Fabre-Taxy et alii, 1965). Later studies of the faunal content have shown that the representatives of the genus Dufrenoyia can co-exist with ammonites of the Lower Aptian (Conte, 1994). And more detailed research involving lithology, sedimentology and geochemistry has shown that the change of facies is more gradual (Moullade et alii, 2000b; Masse, 2000; Renard & de Rafélis, 2000). Whatever the case may be, it seems more appropriate to define the Bedoulian on the basis of a monophyletic zonation, taking into consideration the successive steps in the evolution of the Deshayesitidae, to which the genus Dufrenoyia belongs.

Furthermore, throughout the continuum of faunal evolution the passage from one biozone to another is rarely delimited sharply. If ammonite assemblages evolve in marked fashion at the beginning of the D. furcata Zone, their evolution is even more important in the basal Gargasian where the ammonite fauna is even richer and more diverse: the extinction of Dufrenoyia is almost coincident with the appearance of numerous new species of Epicheloniceras [E. martini (d'Orbigny), E. martini var. orientalis (Sayn), E. martini var. caucasica (Anthula), E. martinioides Casey, E. tschernyschewi (Sinzow), E. subnodosocostatum (Sinzow), [E. buxtorfi (Jacob)], Parahoplites [P. melchioris Anthula, P. transitans Sinzow, P. maximus Sinzow, etc.], Acanthoplites [A. ashiltaensis Anthula)], Colombiceras [C. crassicostatum (d'Orbigny), C. caucasica Luppov, C. tobleri (Jacob et Tobler)] and many Phylloceratidae.

For all of these reasons we propose to maintain the existing statu quo, that is to define the limit between the Lower and Middle Aptian by the FAD of E. subnodosocostatum. This datum is approximately coincident with the disappearance of the genus Dufrenoyia and consequently our proposal leads us to restrict the whole range of the D. furcata Zone to the lower Aptian.

Conclusion

In this paper we have attempted: 
1) to give a detailed, bed-by-bed inventory of the faunal content of the zones of the Lower Aptian in the Cassis-La Bédoule area 
2) to update to some extent the systematic descriptions of their respective faunas. The evolution of Lower Cretaceous ammonites in the stratigraphic succession as it can be traced at Cassis-La Bédoule is very instructive and may be used as a guide to improve the placement of isolated fossil finds in other regions, like southeastern France. Our results show clearly that the doubts expressed by several Russian authors (see above – the introductory portion of this paper) are not justified and that the historical stratotype may still constitute a type-locality usable for Lower Aptian biostratigraphy in the Mediterranean domain.

The principal stages of this evolution may be summarized as follows:

In the Tethyan domain evolute Ancyloceratidae characterize a constant level of terminal Barremian age; they died out at the same time as most Barremian taxons did, that is at or very near the Barremian-Aptian boundary.

As dominant forms these heteromorphs are replaced by successive representatives of the Deshayesitidae, a family that is characteristic of the lower Aptian. Their evolution permits the subdivision of this substage into four zones.

The last genus of the Deshayesitidae, i.e. Dufrenoyia, becomes extinct near or slightly after the FAD of Epicheloniceras, which has always been considered a Gargasian taxon. The first appearance of Epicheloniceras is accompanied by a rich and diverse renewed association that includes various Colombiceratinae and Parahoplitidae.

Numerous species of Deshayesites, most of them described in the Turkmenian or Trans-Caspian regions, have been formally identified in the continuous succession of the Lower Aptian at Cassis-La Bédoule: Paradeshayesites oglanlensis, Paradeshayesites planicostatus, Paradeshayesites weissiformis, D. luppovi, D. dechyi, D. bogdanovae, D. rarecostatus, Dufrenoyia sinzovi, D. fursovae.

It is now well-established that in the Lower Aptian stratotype other forms occur, described originally in the Boreal domain and collected from the Forbesi, Deshayesi and Bowerbanki zones of southeastern England (Casey, 1964). They include Paradeshayesites callidiscus, Deshayesites sp. gr. spathi/normani, D. formosus, Paradeshayesites grandis, P. geniculatus, D. cf. gracilis, Paradeshayesites cf. involutus, Dufrenoyia notha, D. truncata, D. formosa.

This mixture of Boreal and Tethyan forms at Cassis-La Bédoule increases the interest of the stratotype even more, for it permits precious correlations between the two domains.

Acknowledgements

The authors wish to thank Gérard Delanoy (University of Nice-Sophia-Antipolis, France) for his very useful suggestions and indications dealing with Turkmeniceras from SE France. They also thank Tamara N. Bogdanova (Vsegei, St Petersburg, Russia), Miguel Company (University of Granada, Spain) and Jaap Klein (Natural History Museum, Leiden, the Netherlands), for having led the authors, by their constructive suggestions, to improve the initial manuscript. We are very much indebted to Nestor Sander for having linguistically upgraded this paper. Special thanks are also due to Valérie Ménage (Agence régionale de l'environnement de Haute-Normandie, Rouen, France) and Robert Busnardo (Claude Bernard University, Lyon, France) for providing us with scans of plates from the original d'Orbigny's memoirs.

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Figures

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Figure 1: Location of the Cassis-La Bédoule area.

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Figure 2: Late Barremian /Early Aptian (Bedoulian) biozonation in the stratotypical area of Cassis-La Bédoule - SE France. Bed numbering is that used in Moullade et alii (2000b).

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Figures 3 (a-b): Uppermost part of the Comte quarry in 1970, and base of the Middle Aptian (above bed 178).

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Figure 4: Location of the studied sections in the Cassis-La Bédoule area.

Figure 5: Dufrenoya dufrenoyi (d'Orbigny, 1840); type of the "Paléontologie française" 1st edition (16 ribs per half whorl).

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Figure 6: Dufrenoya dufrenoyi (d'Orbigny, 1841); 2nd representation of "A. Dufrenoyi" in the definitive edition of the "Paléontologie française" (20 ribs per half whorl).

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Figures 7-9: Lower Aptian composite section of the Cassis-La Bédoule area, with the position of the collected species (Deshayesitidae p.p. max.). Lithologic unit and bed numbering is that used in Moullade et alii (2000b).

Plates

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Plate 1:

Fig. 1.- Deshayesites luppovi (Bogdanova, 1991) (ABR32), Le Brigadan section, bed 61. P. oglanlensis Zone.

Fig. 2.- Deshayesites luppovi Bogdanova, 1983) (ABR279), Les Caniers section, bed 65. P. oglanlensis Zone.

Fig. 3.- Paradeshayesites oglanlensis (Bogdanova, 1983) (ABR271), Le Brigadan section, bed 63, P. oglanlensis Zone.

Fig. 4.- Deshayesites luppovi Bogdanova, 1983 (ABR285), Les Caniers section, bed 72. P. oglanlensis Zone.

Fig. 5.- Paradeshayesites weissiformis (Bogdanova, 1983) (ABR272), Le Brigadan section, bed 64. P. oglanlensis Zone

Fig. 6.- Paradeshayesites weissiformis (Bogdanova, 1983) (ABR278), Les Caniers section, bed 82. P. oglanlensis Zone

Fig. 7.- Paradeshayesites sp. aff. planicostatus (Bogdanova, 1991) (ABR33), Les Caniers section, bed 63. P. oglanlensis Zone.

Fig. 8.- Paradeshayesites sp. aff. planicostatus (Bogdanova, 1991) (ABR301), Les Caniers section, bed 67. P. oglanlensis Zone.

Fig. 9.- Paradeshayesites sp. (ABR35), Le Brigadan section, bed 63. P. oglanlensis Zone.

Fig. 10.- Paradeshayesites sp. aff. planicostatus (Bogdanova, 1991) (ABR282), Les Caniers section, bed 82. P. oglanlensis Zone.

Fig. 11.- Paradeshayesites oglanlensis (Bogdanova, 1983) (ABR281), Les Caniers section, bed 78. P. oglanlensis Zone.

Fig. 12.- Deshayesites luppovi Bogdanova, 1983 (ABR36), Les Caniers section, bed 78. P. oglanlensis Zone.

Fig. 13.- Paradeshayesites oglanlensis (Bogdanova, 1983) (ABR30), Le Brigadan section, bed 63. P. oglanlensis Zone.

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Plate 2:

Fig. 1.- Deshayesites bedouliensis Cecca, Ropolo et Gonnet, 1999 (BW112), Le Brigadan section, bed 61. P. oglanlensis Zone.

Fig. 2.- Deshayesites bedouliensis Cecca, Ropolo et Gonnet, 1999 (BW021), Les Caniers section, bed 61. P. oglanlensis Zone.

Fig. 3.- Paradeshayesites weissiformis (Bogdanova, 1983) (BW003), Les Caniers section, bed 64. P. oglanlensis Zone.

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Plate 3:

Fig. 1.- Deshayesites sp. aff. consobrinus (d'Orbigny, 1841) (BW066), Le Brigadan section, bed 62. P. oglanlensis Zone.

Fig. 2.- Deshayesites bedouliensis Cecca, Ropolo et Gonnet, 1999 (BW270), Le Brigadan section, bed 62. P. oglanlensis Zone.

Fig. 3.- Deshayesites bedouliensis Cecca, Ropolo et Gonnet, 1999 (BW014), Highway A. 52 section, bed 61. P. oglanlensis Zone.

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Plate 4:

Fig. 1.- Deshayesites sp. aff. luppovi (macroconch?) Bogdanova, 1983 (ABR279), Les Caniers section, bed 72. P. oglanlensis Zone.

Fig. 2.- Paradeshayesites callidiscus (Casey, 1961) var. rugosus (Casey, 1964) (ABR388), Les Fourniers section, bed 110. P. weissi Zone.

Fig. 3.- Deshayesites dechyi Papp, 1907 (ABR46), Les Fourniers section, bed 125. P. weissi Zone.

Fig. 4.- Paradeshayesites weissi (Neumayr et Uhlig, 1881) (ABR289), Les Fourniers section, bed 110. P. weissi Zone.

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Plate 5:

Fig. 1.- Deshayesites gr. spathi/normani Casey, 1964 (ABR323), Les Fourniers section, bed 111. P. weissi Zone.

Fig. 2.- Deshayesites dechyi Papp, 1907 (ABR502), Les Fourniers section, bed 125. P. weissi Zone.

Fig. 3.- Deshayesites planus Casey, 1964 (ABR321), Les Fourniers section, bed 116. P. weissi Zone.

Fig. 4.- Deshayesites evolvens Luppov, 1952 (ABR489), Les Fourniers section, bed 115. P. weissi Zone.

Fig. 5.- Deshayesites euglyphus Casey, 1964 (ABR500), Les Fourniers section, bed 112. P. weissi Zone.

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Plate 6:

Fig. 1.- Deshayesites consobrinus (d'Orbigny, 1841) (BW076), Les Fourniers section, bed 115. P. weissi Zone.

Figs. 2 & 3.- Deshayesites forbesi Casey, 1961 (ABR42 a & b), Les Fourniers section, bed 117. P. weissi Zone.

Fig. 4.- Deshayesites forbesi Casey, 1961 (ABR47), Les Fourniers section, bed 117. P. weissi Zone.

Fig. 5.- Paradeshayesites weissi (Neumayr et Uhlig, 1881) (ABR50), Les Fourniers section, bed 113. P. weissi Zone.

Fig. 6.- Deshayesites consobrinus (d'Orbigny, 1841) (ABR278), Les Fourniers section, bed 115. P. weissi Zone.

Fig. 7.- Deshayesites euglyphus Casey, 1964 (ABR490), Les Fourniers section, bed 120 P. weissi Zone.

Fig. 8.- Paradeshayesites weissi (Neumayr et Uhlig, 1881) (ABR016), Les Fourniers section, bed 113. P. weissi Zone.

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Plate 7:

Fig. 1.- Paradeshayesites callidiscus (Casey, 1961) var. rugosus (Casey, 1964) (ABR43), Les Fourniers section, bed 119. P. weissi Zone.

Fig. 2.- Paradeshayesites weissi (Neumayr et Uhlig, 1881) (ABR29), Les Fourniers section, bed 113. P. weissi Zone.

Fig. 3.- Deshayesites cf. dechyi Papp, 1907 (ABR501), Les Fourniers section, bed 137. P. weissi Zone.

Fig. 4.- Deshayesites forbesi Casey, 1961 (ABR318), Les Fourniers section, bed 117. P. weissi Zone.

Fig. 5.- Deshayesites consobrinus (d'Orbigny, 1841) (SCP4), Les Fourniers section, bed 127. P. weissi Zone.

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Plate 8:

Fig. 1.- Deshayesites dechyi Papp, 1907 (ABR14), Les Fourniers section, bed 138c. D. deshayesi Zone.

Fig. 2.- Deshayesites evolvens Luppov, 1952 (Abm311), Les Fourniers section, bed 115. P. weissi Zone.

Fig. 3.- Deshayesites sp. gr. spathi/normani Casey, 1964 (ABR340), Les Fourniers section, bed 111. P. weissi Zone.

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Plate 9:

Fig. 1.- Deshayesites sp. gr. spathi/normani Casey, 1964 (RG342), Les Fourniers section, bed 126. P. weissi Zone.

Fig. 2.- Paradeshayesites cf. involutus (Spath, 1930) (RG325), Les Fourniers section, bed 165. D. deshayesi Zone.

Fig. 3.- Deshayesites cf. planus Casey, 1964 (ABR362), Les Fourniers section, bed 122. P. weissi Zone.

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Plate 10:

Fig. 1.- Deshayesites deshayesi (Leymerie, 1841) (ABR512), Zone Les Fourniers section, bed 130. D. deshayesi Zone.

Fig. 2.- Deshayesites deshayesi (Leymerie, 1841) (ABR511), Les Fourniers section, bed 135. D. deshayesi Zone.

Fig. 3.- Paradeshayesites grandis (Spath, 1930) (ABR347), Comte Quarry section, bed 161a. D. deshayesi Zone.

Fig. 4.- Deshayesites cf. gracilis Casey, 1964 (ABR336), Les Fourniers section, bed 159. D. deshayesi Zone.

Fig. 5.- Paradeshayesites grandis (Spath, 1930) (ABR348), Comte Quarry section, bed 164. D. deshayesi Zone.

Fig. 6.- Deshayesites geniculatus Casey, 1964 (ABR508), Les Fourniers section, bed 166. D. deshayesi Zone.

Fig. 7.- Deshayesites bogdanovae Avram, 1999 (ABR149), Les Fourniers, bed 118. P. weissi Zone.

Fig. 8.- Dufrenoyia fursovae Bogdanova, 1991 (ABR602), Comte Quarry section, bed 171. Dufrenoyia furcata Zone.

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Plate 11:

Fig. 1.- Paradeshayesites grandis (Spath, 1930) (ABR354), Comte Quarry section, bed 161a. D. deshayesi Zone.

Fig. 2.- Roloboceras hambrovi (Forbes, 1845) (ABR1220), Comte Quarry section, bed 148. D. deshayesi Zone.

Fig. 3.- Tropaeum bowerbanki (Sowerby, 1837) (ABR2420), Comte Quarry section, bed 174. Dufrenoyia furcata Zone.

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Plate 12:

Fig. 1.- Paradeshayesites cf. involutus (Spath, 1930) (RG329), Comte Quarry section, bed 168. D. deshayesi Zone., P. grandis Subzone.

Fig. 2.- Dufrenoyia dufrenoyi (d'Orbigny, 1841) (ABR332), Comte Quarry section, bed 175. Dufrenoyia furcata Zone.

Fig. 3.- Dufrenoyia furcata (Sowerby, 1836) (ABR1425), Comte Quarry section, bed 171. D. furcata Zone.

Fig. 4.- Dufrenoyia notha Casey, 1964 (ABR333), bed 172, extreme base of the La Marcouline quarry. D. furcata Zone.

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