Contents

[Introduction] [1. The nomenclatural status of the species ...]
[2. The nomenclatural status of the genus ...] [3. The acceptation ...]
[4. The biostratigraphical value ...] [Conclusions]
and ... [Bibliographic references]

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Discussion of: Problems in the identity of
"Crioceras" barremense Kilian, 1895
(Ancyloceratida, Late Barremian), and their proposed resolution,
by D. Bert et alii (CG2010_A01)

[Alternative title: The nomenclatural status and the acceptation
of the genus Barrancyloceras Vermeulen, 2000, and of its type species]

Jean Vermeulen

Grand rue, 04330 Barrême (France)

Manuscript online since April 27, 2011

Abstract

This work is a reply to the paper of Bert et alii (2010) who contested the validity of the genus Barrancyloceras and its type species. The answers and precisions brought up herein deal with:

• the nomenclatural status of Barrancyloceras barremense (Kilian, 1895);
• the nomenclatural status of the genus Barrancyloceras Vermeulen, 2000;
• the understanding of the species Barrancyloceras barremense (Kilian, 1895);
• the value, as a subzone index species of subzone, of Barrancyloceras barremense and B. alpinum.

Key Words

Hemihoplitidae; Barrancyloceras; Upper Barremian.

Citation

Vermeulen J. (2011).- Discussion of: Problems in the identity of "Crioceras" barremense Kilian, 1895 (Ancyloceratida, Late Barremian), and their proposed resolution, by D. Bert et alii (CG2010_A01) [Alternative title: The nomenclatural status and the acceptation of the genus Barrancyloceras Vermeulen, 2000, and of its type species].- Carnets de Géologie / Notebooks on Geology, Brest, Article 2010/01_Reply (CG2010_A01R)

Résumé

Discussion sur : Le problème de l'identité de "Crioceras" barremense Kilian, 1895 (Ancyloceratida, Barrémien supérieur), et ses possibles solutions, par D. Bert et alii (CG2010_A01) [Titre alternatif : Le statut nomenclatural et la compréhension du genre Barrancyloceras Vermeulen, 2000, et de son espèce-type].- Ce travail est une réponse au travail de Bert et alii (2010) qui ont discuté la validité du genre Barrancyloceras et de son espèce-type. Les réponses et précisions apportées ici concernent :

• le statut nomenclatural de Barrancyloceras barremense Kilian, 1895 ;
• le statut nomenclatural du genre Barrancyloceras Vermeulen, 2000 ;
• la compréhension de l'espèce Barrancyloceras barremense (Kilian, 1895) ;
• la valeur, en tant qu'espèces-index de sous-zone, de Barrancyloceras barremense et de B. alpinum.

Mots-Clefs

Hemihoplitidae; Barrancyloceras; Barrémien supérieur.

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Introduction

The nomenclatural validity of the genus Barrancyloceras Vermeulen, 2000, and its species-type, Barrancyloceras barremense Kilian, 1895, has been recently questioned by Bert et alii (2010). On the basis of a careful examination, I believe that the arguments exposed by these authors are obviously either invalid or not accurate. The aim of this paper is to bring new light and precisions on the nomenclatural status of the concerned taxa. Besides, connected topics will be discussed such as the identity and understanding of Barrancyloceras barremense, and the value, as biostratigraphical index species, of B. barremense and B. alpinum.

1. The nomenclatural status of the species barremense (Kilian, 1895)

Bert et alii (2010, p. 1) recommend that "the use of the species "Crioceras" barremense be avoided, in particular as an index species, along with that of the genus Barrancyloceras Vermeulen for which "C." barremense is used as reference". In order to understand better the nomenclatural status of the species barremense Kilian, 1895, and, consequently the nomenclatural status of the genus Barrancyloceras Vermeulen, 2000, it is necessary to follow step by step, including comments, the successive stages of the original story of this species.

1888 (1887): Uhlig describes, compares and illustrates (1887, p. 95, Pl. IV, fig. 3.a, b, c), under the name "Crioceras sp. ind. aff. Römeri Neum. Uhl.", a specimen of the Klipstein's collection from Gardenazza. In agreement with the original designation, this specimen is left by its author in open nomenclature.

1895: In the report of an excursion from Barrême to Blieux and Castellane, close to the hamlet La Maurelière, Zürcher (1895, p. 905) mentions, among the collected material, "Crioceras barremense Kilian [= Crioc. n. sp. aff. Roemeri Uhlig (Gardenazza)]". At this time, this specimen which, according to Zürcher, was identified by Kilian, is thus referred only to that of Uhlig (1887, Pl. IV, fig. 3.a, b, c).

1896 (1895): In a work dealing with the Neocomian of the vicinity of Moustiers Sainte-Marie (locality Nauvin) located in the department of Basses-Alpes), Kilian and Leenhardt (1895, p. 978) list among the collected species (translation): "Crioceras barremense Kilian (species of the group of Cr. hammatoptychum N. et Uhlig and Roemeri N. et Uhlig). This species, that would be of interest to fully describe, was illustrated under the name Cr. ind. aff. Roemeri by Mr. Uhlig (Gardenazza, Pl. IV, fig. 3). It also occurs at Blieux". Such an unquestionable reference to the work of Uhlig implies that the specimen described, compared and illustrated by this author (1887, p. 95, Pl. IV, fig. 3.a, b, c) represents Crioceras barremense Kilian, 1895, by the reference of Kilian to the work of Uhlig. In the work of Klein et alii (2007) to which I contributed with, among others, Busnardo and Delanoy, this reference is regarded as an original designation.

1899: Simionescu briefly describes and illustrates two specimens (1899, p. 488, Pl. 1, figs. 4-5), under the name Crioceras barremense Kil. Following the original concept, this author indicates, without ambiguity, the specimen of Uhlig as the type of Crioceras barremense Kil. (translation): "the type of this species was illustrated by Mr. Uhlig under the name Crioc. ind. aff. Roemeri" and quotes, by a bibliographical reference in an infrapaginal note, the work of Uhlig "1887, Pl. IV, fig. 3".

The original specimen of Uhlig (1887, p. 95, Pl. IV, fig. 3.a, b, c) is thus the lectotype (Kilian & Leenhardt, 1895; Simionescu, 1899) of the species Crioceras barremense Kilian, 1895, and the type locality of this species is Gardenazza (Tyrol). There is no need to establish the identity of Kilian's species by new collections at Nauvin for it is not the type locality.

2. The nomenclatural status of the genus Barrancyloceras Vermeulen, 2000

1998: Vermeulen and Bert introduce the genus Barrancyloceras with Barrancyloceras barremense (Kilian, 1895) as its type species. Barrancyloceras hoheneggeri (Uhlig, 1883), Barrancyloceras hammatoptychum (Uhlig, 1883), Barrancyloceras klipsteini (Uhlig, 1887) and Barrancyloceras bailense (Vermeulen, 1996) are also included in this genus. At this date, this genus is a nomen nudum (Klein et alii, 2007, p. 223) because the distinctive criteria, according to article 13.1.1. of the I.C.Z.N. code, are not specified.

2000: Vermeulen (2000, p. 127) gave the diagnosis of the genus Barrancyloceras and thus validates the nomenclatural status, as specified by Klein et alii (2007, p. 223) specify it.

2007: Vermeulen and Lazarin (2007, p. 33) carried out the first revision of the type species, Barrancyloceras barremense (Kilian, 1895), by providing an emendation of the original diagnosis, including new precisions. Because the lack of all original syntype, later confirmed by Bert et alii (2010), these authors describe a neotype.

Some of the arguments brought up by Bert et alii (2010) regarding the validity of this neotype are subject to discussion:

• the article n° 75 of the I.C.Z.N. codes recommends preliminary contacts before designation of a neotype. This article, even not applicable to the current situation, was respected by a preliminary a priori advertisement and illustration of that standard specimen in a publication (Vermeulen, 2005);
• in the case of a priori advertisement, the article 75 of the I.C.Z.N. code does not invalidate the specimen priori indicated, contrary to what is affirmed by Bert et alii (2010, p. 5-6), but only the designation;
• currently, some species with tripartite coiling can be maintained in the genus Barrancyloceras Vermeulen, 2000, with a status of peripheral taxa, by their characteristics ornaments of the spire; they also must maintained in this genus by the fact that no new characteristic taxa, of generic and of specific rank, were ever described or figured to accommodate these forms with whorl, shaft, bend and retroversum;
• the genus Barrancyloceras Vermeulen, 2000, whose type is clearly defined and definition respects the articles of the I.C.Z.N. code, is a valid genus.

3. The acceptation of Barrancyloceras barremense Kilian, 1895

Regarding the identity and the acceptation of Barrancyloceras barremense, new comments are to be put forward. Despite what was affirmed by Bert et alii (2010, p. 6):

• the neotype described by Vermeulen and Lazarin (2007) is a little more robust than the specimen drawn by Uhlig (1887, Pl. IV, fig. 3a) however its youngest part show the same ornamentation, the same regular alternation of intermediate ribs/main ribs, the same stage of appearance of the intermediate ribs and, at about 90 mm of diameter, the same ratio intermediate ribs/ main ribs as well as a very close ratio intercalary ribs/main ribs. These similarities imply that the two specimens are conspecific.
• the cross-section of the neotype is (Vermeulen & Lazarin, 2007, p. 35, translation): "angular on the principal and intermediate ribs, in particular on the last whorl, and ellipsoidal on the intercalated ribs and in the furrows between the ribs". This is in agreement with the original figure of Uhlig (1887) who also described an oblong section in the text.
• the specific characters of Barrancyloceras barremense were fixed by the first revisers (Vermeulen & Lazarin, 2007) in accordance with articles 12 and 24 of the I.C.Z.N. code;
• the original specimen of Uhlig (1887, Pl. IV, fig. 3), by its dimensions and ratios is closer to the neotype described and illustrated by Vermeulen & Lazarin (2007) than the holotype of Pseudoshasticrioceras bersaci (Bert et alii, 2010, p. 4, table 1). Similarly, the ornamentation of Pseudoshasticrioceras bersaci does not match that of Uhlig's original figure;
• the very regular alternation between the main trituberculated ribs, bituberculated intermediate ribs and non tuberculated intercalated ribs, is an exclusive character of Barrancyloceras barremense protograph and neotype; these peculiar ornamental features, regular and well developed on the last known whorl of this species, are not found in any other species nor in specimens with similar ribbing;
• the section of the whorl, the trituberculation which persists at least until approximately thirty millimetres height of whorl without sign of weakening (Uhlig, 1887, Pl. IV, fig. 3), the regular distribution of main trituberculated ribs, bituberculated intermediate ribs and non tuberculated intercalated ribs, imply that Barrancyloceras barremense, differs significantly from all the species of the genus Camereiceras and Pseudoshasticrioceras, contrary to what is affirmed by Bert et alii (2010).
• trying to prove the possible classification of Barrancyloceras barremense in both the genera Camereiceras and Pseudoshasticrioceras, Bert et alii (2010) rather points out that the generic characters of these two genera are ill-defined.

Starting from an another remark of these authors, I must specify: if Leroyceras mascarellii (Vermeulen, 2005) is a junior synonym of "Gassendiceras" alpinum (d'Orbigny, 1850), as indicated by Bert et alii (2010), then the genus Leroyceras Vermeulen, 2006, is a senior synonym of "Gassendiceras" Bert, 2006. Obviously, synonymy Leroyceras mascarellii - Barrancyloceras alpinum is irrelevant, because these two species differ significantly by the respective ontogenetic developments of their ornamentation, very different one from the other.

4. The biostratigraphical value of Barrancyloceras barremense and B. alpinum

Busnardo (1984), who also co-authors the work of Bert et alii (2010), introduced Barrancyloceras barremense, then based on a broad understanding and needing revision, as a zonal index species. Later on, this species was revised by Vermeulen & Lazarin (2007), leading to a better understanding of this taxon. It is clear that Barrancyloceras barremense is not a good index-species, not because of the difficulty of its identification, as suggested by Bert et alii (2010), but mainly by its scarcity during its acmeic phase. Barrancyloceras alpinum too was revised by Vermeulen & Lazarin (2007), but this species, if we take into account the specific characters highlighted by these two authors, is also rare and its broad understanding will place it, as an index species, in the same case as the broad understanding of Barrancyloceras barremense in the eighties.

Pending the discovery of a better index species, Barrancyloceras alpinum can be used instead of Barrancyloceras barremense, but the precise origin, the mother species, the geographical distribution and the precise stratigraphical range, of the d'Orbigny's species are not known and for these reasons it is not a so good index as Bert et alii (2010) write.

Conclusion

The points herein discussed show:

• the valid nomenclatural status of the genus Barrancyloceras Vermeulen, 2000;
• the valid nomenclatural status of Barrancyloceras barremense Kilian, 1895.

They confirm also the poor value of Barrancyloceras barremense as index-species and the poor value of Barrancyloceras alpinum for the same use.

Bibliographic references

Bert D., Busnardo R., Delanoy G. & Bersac S. (2010).- Problems in the identity of "Crioceras" barremense Kilian, 1895 (Ancyloceratida, Late Barremian), and their proposed resolution.- Carnets de Géologie / Notebooks on Geology, Brest, Article 2010/01 (CG2010_A01), 17 p.

Busnardo R. (1984).- Barrémien. In : Synthèse géologique du Sud-Est de la France.- Bureau de Recherches Géologiques et Minières, Mémoire, Orléans, n° 125, p.289-290.

Kilian W. & Leenhardt F. (1895).- Sur le Néocomien des environs de Moustiers S^te-Marie (Basses-Alpes).- Bulletin de la Société géologique de France, Paris, (3ème Série), t. XXIII, fasc. 3, p. 970-981.

Klein J., Busnardo R., Company M., Delanoy G., Kakabadze M., Reboulet S., Ropolo P., Vasicek Z. & Vermeulen J. (2007).- Lower Cretaceous Ammonites III Bochianitidae, Protancyloceratoidea, Ancyloceratoidea, Ptychoceratoidea. In: Riegraf W. (ed.), Fossilium Catalogus I: Animalia.- Backhuys Publishers, Leiden, 381 p.

Orbigny A. d' (1850).- Prodrome de paléontologie stratigraphique universelle des animaux mollusques et rayonnés faisant suite au cours élémentaire de paléontologie et de géologie stratigraphique. Vol. 2.- Masson, Paris, 428 p.

Simionescu I. (1899).- Note sur quelques ammonites du Néocomien français.- Annales de l'Université de Grenoble, vol. 11, fasc. 3, p. 1-16.

Uhlig V. (1887).- Ueber neocom Fossilien vom Gardenazza in Südtirol, nebst einen Anhang über das Neocom von Ischl.- Jahrbuch der kaiserlich-königlichen geologischen Reichsanstalt, Wien, Band 37, Heft 1, p. 69-108.

Vermeulen J. (2000).- Nouvelles données sur les répartitions stratigraphiques, les évolutions et les classifications de trois familles d'ammonites du Crétacé inférieur.- Géologie Alpine, Grenoble, n° 75, p. 123-132.

Vermeulen J. (2005).- Boundaries, ammonite fauna and main subdivisions of the stratotype of the Barremian.- Géologie Alpine, Grenoble, (Série spéciale "Colloques et Excursions"), n° 7, p. 147-173.

Vermeulen J. & Bert D. (1998).- Sur l'ammonitofaune du Barrémien de la Saurée près de Tourette-Levens (Alpes-Maritimes, France).- Riviéra Scientifique, Nice, vol. 82, p. 77-88.

Vermeulen J. & Lazarin P. (2007).- Nouvelles données sur les Ancyloceratoidea Gill, 1871 (Ancyloceratina Wiedmann, 1966 emend. Vermeulen, 2005) du Barrémien supérieur et de l'Aptien inférieur.- Annales du Muséum d'Histoire Naturelle de Nice, t. XXII, p. 27-86.

Zürcher P. (1895).- Compte rendu de la course du 24 Septembre de Barrême à Blieux & à Castellane.- Bulletin de la Société Géologique de France, Paris, (3ème Série), t. XXIII, p. 902-916.

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