Late Early Devonian Rostroconchia (Mollusca) from Hamar Laghdad (Morocco)

摘要

The late Early Devonian rostroconch fauna from the Amerboh Group of Bou Tchrafine in the Hamar Laghdad area is described. The few specimens are assigned to the genera Hoareicardia and Barrandeicardia within the Hippocardiidae of the Hippocardioidea. The material confirms the difficulties in recognizing different shell layer architecture in conocardiid rostroconchs, which is a prerequisite for specific determination. The presence of Hoareicardia in the late Early Devonian of Morocco denotes the distribution of the genus in both the northern (Laurussia) and southern (Gondwanan) shelf margins of the Rheic Ocean, and Barrandeicardia furthermore provides evidence of a probable connection with the highly diverse rostroconch assemblages of Perunica and Armorica.