Body size of orthoconic cephalopods from the late Silurian and Devonian of the Anti‐Atlas (Morocco)

摘要: Fluctuations in body size of orthoconic cephalopods are reported from late Silurian to Late Devonian sediments at several locations the Tafilalt and Dra-Valley (Anti-Atlas, Morocco). The combination measurements diameters apical angles allows reconstruction their total conch (length volume), which revealed a strongly right-skewed distribution with an average length 278 mm, while largest actinocerids exceeded 2 m. Within examined groups (Actinocerida, Orthocerida, Pseudorthocerida), there is no uniform trend, but rather frequent fluctuations maximum sizes Lochkovian early Emsian. Body decreased times extinction events, stable periods mostly associated increase. Additionally, correlates well gamma diversityand global d13C values. Furthermore, angle septal diameter orthocones appear correlate, only when mean values compared across beds. Anti-Atlas, size, Cephalopoda, Devonian, Morocco, orthocones.