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Megathiris

   
   

Sous-embranchement (subphylum) des Rhynchonelliformea
Classe des Rhynchonellata
Ordre des Terebratulida
Sous-Ordre des Terebratellidina
Super-famille des Megathyridoidea
Famille des Megathyrididae

 
 

 
 
 
 


Genus Megathiris d'Orbigny, 1847
 

Megathiris d'Orbigny, 1847, p. 269, nom. nov. pro Argiope Deslongchamps, 1842, p. ix, non Audouin in Savigny, 1827 [*Anomia detruncata Gmelin, 1791, p. 3,347; OD] [=Megathyris Bronn, 1848, p. 244, nom. van.; Argyope Davidson, 1850, p. 65, obj., non Savigny, 1826].

[Type-species = Anomia detruncata Gmelin, 1791 p. 3347]

Small, broadly transverse, hinge line straight; ventribiconvex, multiplicate, anterior commissure rectimarginate to slightly uniplicate; beak short, attrite; foramen hypothyrid, deltidial plates disjunct. Hinge teeth small, elongate; pedicle collar supported by long, narrow median septum and 2 subdued lateral septa extending almost to anterior margin. Cardinal process small, transverse, grooved; cardinalia with low hinge platform uniting 2 prominent socket ridges; crura short, widely separated, crural processes prominent, horizontal, pointed; median septum very long, narrow, high; flanked in anterior part of shell by 2 lateral septa reaching to near middle of dorsal valve; loop of 2 slender, arcuate descending branches free only near crura, attached to base of crura, valve floor, and anterior extremities of lateral septa and median septum; lophophore attached to dorsal mantle, ptycholophous; rarely weakly spiculate.

Upper Cretaceous (Campanian) - Present

Diagnosis from volume 5 of the Treatise on Invertebrate Paleontology (2007)


Species of Megathiris
  • M. detruncata (Gmelin, 1791) - see photography below
  • M. barroisi (Schulgin, 1884)
  • M. capensis Jackson, 1952

  • Diagnosis


    Megathiris detruncata: in cave, 12 m depth - Madeira.   Copyright © Peter Wirtz

    Megathiris detruncata


    Megathiris detruncata (Gmelin, 1791)

    Type locality: « Habitat in mari mediterraneo, coralliis adhaerens ».
    Depth range: 5 - 896 m

    Anomia decollata Chemnitz, 1785
    Terebratula urna antiqua Risso, 1826
    Terebratula cardita Risso, 1826
    Terebratula aperta Blainville, 1828
    Terebratula dimidiata Scacchi, 1833
    Argiope detruncata (Gmelin): Eudes-Deslongchamps (1842)
    Orthis detruncata (Gmelin): Philippi (1844)
    Megathiris detruncata (Gmelin) : d'Orbigny (1847)
    Terebratula pectiniformis Costa, 1851
    Argiope decollata: Jeffreys (1878) ; Davidson (1887)

    Diagnosis -