中国科学院南京地质古生物研究所机构知识库

The oyster-like, dimyarian, cementing bivalve genus Protostrea CHEN in GU et al., 1976 and its type species Protostrea sinensis (Hsu in Hsu & CHEN, 1943) from the upper Anisian (Middle Triassic) of the Qingyan Formation, Guizhou Province, south-western China, are re-described and emended. The genus Most probably is the earliest representative of the family Dimyidae. But Protostrea is a peculiar dimyid because in adult growth stages its shell is fairly large and thick, the resilifer is rectangular, broad, shallow and sometimes multiple, and the crura usually are weak. These features resemble some thick-shelled Prospondylidae. The features of pre-adult growth stages of P. sinensis indicate possible affinities to the order Pectinoida.