Opis

Conch thick-discoidal to globular with whorl section involute and umbilicus very small to closed; late ontogenetic shell modifications resulted in changes of whorl section, development of an apertural constriction or shell thickening; growth lines biconvex, usually crenulated; longitudinal lirae usually stronger than growth striae, rarely without spiral ornamentation; suture-line with Y-shaped ventral lobe and acute or subacute ventrolateral saddle; tendency of trifurcation of adventitious lobe only; sutural formula of advanced forms.

Synonimy

Zasięg czasowy

Carboniferous; Serpukhovian - Bashkirian

Literatura

Ruzhencev, V.E. 1957. Protsvetanie i krizisy v istorii ammonoidei. Doklady Akademii Nauk SSSR 115 (4): 791-794.