MIDDLE CAMBRIAN PELECYPODS FROM THE ANTI-ATLAS, MOROCCO Gerd GEYER] and Michael STRENG 2 I Institl1t fUr PaHiontologie. Bayerische Jl1lil1s-Maximilians-Universitat WUrzburg. Pleicherwall 1. D-97070 WUrzburg. Germany. E-mail: gerd.geyer@mail.uni-wuerzburg.de , FB-5 Geowissenschaften. Universitat Bremen. P. O. Box 330 440. D-28334 Bremen. Germany. E-mail: streng@uni-bremen.de Geyer, G. and Streng, M. 1998. Middle Cambrian pelecypods from the Anti-Atlas, Morocco. [Pelecipodos del Cambrico Medio del Anti-Atlas, Marruecos.]. Revista Espanola de Paleontologfa, n° extr. Homenaje al Prof. Gonzalo Vidal, 83-96. ISSN 0213-6937. ABSTRACT A new species of the Early to Middle Cambrian pelecypod genus Pojetaia is reported from the early Middle Cambrian of the Moroccan Anti-Atlas with the new species Pojetaia sarhroensis. Arhollriella opheodol1toides n. gen. and sp. is the first report of a Cambrian pelecypod with an amphidetic, slightly twisted and partly internal ligament and appears to represent a second order of pelecypods in the early Middle Cambrian. Preservation, environment and correlation are discussed. Species of Pojetaia are discussed in detail. lellia is shown to be a junior synonym of Pojetaia. Hence, the species originally described under the names P. r/lI1negari and lellia ovata by Li and Zhou (1986) need to be renamed. Oryzoconcha He and Pei, 1985 is regarded as an invalid taxon. Other Cambrian pelecypods are reviewed briefly. Key words: Pojefaia sarhl'oensis n. sp., Arhouriellidae n. fam., Al'holll'iella opheodonfoides n. gen., n. sp., Pelecypoda, morphology, synonymy, phylogeny, preservation, Middle Cambrian, Morocco, China, Australia. RESUMEN Se define Pojetaia sarhroensis, una nueva especie del genero de pelecipodo Pojetaia del Cambrico Inferior- Cambrico Medio, procedente del Cambrico Medio temprano del Anti-Atlas, Marruecos. Se define tambien Arhollriella opheodontoides n. gen. and sp., que es el primer bivalvo cambrico descrito con ligamento anfidetico ligeramente retorcido y parcialmente interno, pOl' 10 que parece representar un segundo orden de pelecipodos en el Cambrico Medio temprano. Se discute la conservacion, elmedio de vida y la cOlTelacion de este material. Se discuten tambien, en detalle, las especies de Pojetaia. lellia se considera un sin6nimo mas reciente de Pojetaia. Por 10 tanto, el material descrito por Li y Zhou (1986) bajo los nombres P. rlll1negari y lellia ovata debe ser renombrado. Ol),zoconcha He and Pei, 1985 resulta ser un taxon no valido. Se revisan brevemente otros pelecipodos cambricos. Palabras clave: Pojefaia sal'hroensis n. sp., Arhouriellidae n. fam., Arl/OlIl'iella opheodontoides n. gen., n. sp., Pelecypoda, morfologia, sinonimia, filogenia, conservaci6n, Cambrico :NIedio, Marruecos, China, Australia. INTRODUCTION Pelecypods are rare in Cambrian biota. The specimens described herein are the first Middle Cambrian pelecypods from western Gondwana and the first pelecypods from the present-day continent Africa. The only other western Gondwanan Cambrian pelecypods were reported from Lower Cambrian rocks of the Gi::irlitz area, eastern Germany (Elicki, 1994). Fossils that were originally interpreted as the earliest known pelecypods were described from the Iberian Chains, northeastern Spain under the name Lamellodonta simplex (Vogel, 1962, 1975). However, these remains turned out to be distorted valves of the obolellid brachiopod