Litoceras Hyatt 1884

Genus Litoceras Hyatt, 1884 Type species

Nautilus versutus Billings, 1865 (part), from Gargamelle Cove, Pointe Riche Peninsula, western Newfoundland, Canada (lower Table Head Formation, Darriwilian, see Stouge 1984); by original designation.

Thickly subdiscoidal to subglobular conchs with rapidly enlarging, depressed whorls; mature body chamber may become evolute; ornamented with growth lines, which slope apicad from the umbilical shoulder to the hyponomic sinus, growth lines may become fasciculate, and costae may develop which are not, however, prominent, and are not ordinarily evident on the internal mold; straight transverse sutures or faint ventral saddles may develop; siphuncle initially ventral, dorsal by the completion of the second volution (adopted from Flower 1968: 44).

The type specimens (originally described as Nautilus versutus, referred to L. whiteavesi Hyatt, 1894 by Hyatt 1894: 475) have been listed as collected from the St. George and/or Table Head Group of western Newfoundland in Ulrich et al. (1942: 78). However, Flower (1979: 223) stated “after extensive collecting of coiled cephalopods, both from the St. George Group and in the Table Head limestone, it is clear that there is no true Litoceras in the St. George Group nor in any known late Canadian faunas. Specimens very close to L. versutum have been obtained in the Table Head limestone, from which I have obtained at least 35 large coiled cephalopods; all but one belong to Litoceras ”.