Abstract
Gemmellaroia is a conical Permian brachiopod that traditionally has been assigned to the superfamily Richthofeniacea [sic] on the basis of its conical shape and a myocoelidium in the ventral valve. It has been considered unique among brachiopods in opening the shell by having the dorsal valve move straight up, rather than rotating around a hinge axis. Evidence is adduced to warrant transfer of the genus and its cohorts to the superfamily Derbyoidea (totally unrelated to the richthofenioids) and to demonstrate that it was capable of opening in the normal manner, rotating the dorsal valve about a hinge axis. Members of the family include Gemmellaroia (Cossmann, 1898), Loczyella Frech, 1901, Tectaria (Likharev, 1928), and Cyndalia (new genus with type species C. rudistiformis new species).
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
