Ammonoids from the Dasberg Event Interval (upper Famennian) of Jebel Ouaoufilal (Tafilalt, Anti-Atlas, southeastern Morocco)

Abstract A deeply weathered, hypoxic shale package with originally pyritic ammonoids represents the upper Famennian Dasberg Event Interval (basal Dasbergian, Famennian UD V-A 1 , Costaclymenia Genozone) at the Jebel Ouaoufilal (eastern Amessoui Syncline, southern Tafilalt, SE Morocco). It contains abundant small-sized goniatites and clymeniids, with some dominant genera ( Erfoudites, Felisporadoceras, Costaclymenia ) and moderately common taxa (e.g. Prionoceras, Cyrtoclymenia ), but also with rare and new forms that partly have not been sufficiently described. These include Martiniclymenia tenens n. gen. n. sp. (Platyclymeniidae), Cyrtoclymenia variseptata n. sp. (Cyrtoclymeniidae), Acuticlymenia tafilensis n. gen. n. sp. (Rectoclymeniidae), Costaclymenia constricta n. sp. (Costaclymeniidae), Protoxyclymenia sp. juv. (Protoxyclymeniidae), and Kosmoclymenia cf. ebbighauseni juv. (Kosmoclymeniidae). Following a revision of the problematic genus Falciclymenia , Sigmoclymenia n. gen., with the type-species Sigmo. mirabilis (Nikolaeva and Bogoslovsky, 2005) from Kazakhstan, includes all convolute, non-oxyconic “falciclymeniids” without an E-lobe. With ca. 25 species, the Jebel Ouaoufilal ammonoid assemblage is among the most diverse of its age on a global scale. It underlines the rapid radiation in oxygen-depleted facies after the global extinction at the end of Famennian IV (Hembergian).