First selenosteid placoderms from the eastern Anti-Atlas of Morocco; osteology, phylogeny and palaeogeographical implications

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Abstract

Abstract:  A new placoderm assemblage is reported from the Kellwasser facies of the eastern Anti-Atlas, Morocco. This is the first record of an abundant Frasnian placoderm assemblage from Africa. The following new selenosteid taxa are described: Draconichthys elegans gen. et sp. nov., Enseosteus marocanensis sp. nov. and Walterosteus lelievrei sp. nov. In addition, material of Rhinosteus cf. parvulus is figured and described for the first time from Gondwana. The genera Enseosteus, Rhinosteus and Walterosteus are reviewed. ‘Wildungenichthys’ is regarded as a junior subjective synonym of Walterosteus. The new material and a revision of the taxa from Bad Wildungen, Germany, are the basis for a new phylogenetic analysis of the selenosteid arthrodires. The monophyly of the selenosteids is confirmed. The North American selenosteids are a sister group of Moroccan and European selenosteids, excluding Pachyosteus. The Moroccan vertebrate assemblage resembles that of Bad Wildungen. This supports the close palaeogeographical positions of Gondwana and Laurussia during the Late Devonian and indicates that biogeographical barriers for placoderms that could have separated the two assemblages were absent.

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