Gatunek typowy
Dagnachonetes caucasicus Afanas’eva, 1978; Mid Devonian, Eifelian of Azerbaijan

Opis

Shell weakly to moderately concavoconvex; ventral sulcus, dorsal fold sometimes poorly developed (in more arched species); spines orthomorph oblique and symmetrically arranged; ventral interarea apsacline with wide pseudodeltidium and dorsal interarea catacline with chilidium; radial ornamentation of numerous low costellae increasing rapidly in number, mainly by bifurcation in ventral valve; costellae narrowing toward periphery of shell when their numbers increase; hinge teeth laterally elongate, semioval; wide, internally bilobed cardinal process anteriorly bounded by cardinal process pit.

Synonimy

Zasięg czasowy

Early to Mid Devonian (Emsian–Givetian); Europe (Spain, France, Poland, Azerbaijan), Asia (China, Uzbekistan) and Canada.

Literatura