THE LAZARUS AMMONOID FAMILY GONIATITIDAE, THE TETRANGULARLY COILED ENTOGONITIDAE, AND MISSISSIPPIAN BIOGEOGRAPHY

Abstract

A small early Late Viséan (Mississippian) ammonoid assemblage with Entogonites saharensis new species and Goniatites lazarus new species is described from the eastern Anti–Atlas of Morocco, being the first African record of Entogonites. The family Goniatitidae is a typical Lazarus taxon, which, after a gap representing approximately 10 million years, reappears in the fossil record. The genera Entogonites and Goniatites have a wide paleogeographic distribution (northwest Laurentia, northern and southern Variscides, north Gondwana). This indicates ammonoid cosmopolitism at the genus level at the end of the middle Viséan, before late Viséan ammonoid provinces formed. Entogonites with tetrangularly coiled juvenile whorls and with a low aperture probably had a planktonic life- style.