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Fallax

Sous-embranchement (subphylum) des Rhynchonelliformea
Classe des Rhynchonellata
Ordre des Terebratulida
Sous-Ordre des Terebratellidina
Super-famille des Kingenoidea

 
 
 
 
 


Genus Fallax Atkins, 1960
[Type species= Fallax dalliniformis Atkins, 1960 (p. 72)]
[= Laurinia Zezina, 2005, p. 31]

Medium, biconvex, smooth, elongate ovate to subpentagonal, anterior commissure rectimarginate to parasulcate; beak low, erect; beak ridges rounded; deltidial plates conjunct in adults; foramen small, round, permesothyrid. Dental plates lamellar, straight; pedicle collar broad, sessile, impunctate. Cardinalia lamellar with short, well-developed septalium; inner and outer hinge plates well developed, crural bases not differentiated; cardinal process not differentiated; median septum extending anteriorly about three-quarters valve length; crura short, subparallel, crural processes short; loop diploform; lophophore and mantle finely spiculate.

Present

Diagnosis from volume 5 of the
Treatise on Invertebrate Paleontology (2006)
updated on September 20, 2019

Extant Species of Fallax
  • F. dalliniformis Atkins, 1960
  • F. antarcticus Foster, 1974
  • F. neocaledonensis Laurin, 1997
    • Laurinia Zezina, 2005

    Diagnosis
    Diagnosis


    Fallax antarcticus   Foster, 1974

    Type locality: “HU st. 27-35 (62°47'S, 158°12'W): 2288-2342 m.”
    Depth range: 2285 - 2342 m

    Diagnosis in preparation -


    Fallax neocaledonensis   Laurin, 1997

    Type locality: “BIOCAL, station DW 38, 22°59,74'S, 167°15,31'E, profondeur 360 m.”
    Depth range: 33 - 1620 m

    Laurinia Zezina, 2005, p. 31-32 > L. neocaledonensis (Laurin, 1997) : Bitner (2008, 2009)
    Campages furcifera : d’Hondt (1987, p. 37)

    Diagnosis (Laurin, 1997)

    Fallax de forme triangulaire, à bord antérieur quasi rectiligne en vue dorsale. Commissure frontale uniplissée en une voûte arrondie qui n'entraîne la formation d'un pli que sur la partie la plus antérieure de la valve brachiale. Présence de lamelles dentales. Brachidium typiquement campagiforme avec une boucle caracté- ristique en forme de "capuchon".