Machaeracanthus goujetin. sp. (Acanthodii) from the Lower Devonian of Spain and northwest France, with special reference to spine histology

Abstract

ABSTRACT We describe here a new machaeracanthid acanthodian (Machaeracanthus goujeti n. sp.), based on isolated spines, scales and scapulocoracoids from the Lower Devonian (Lochkovian-Pragian) of the Nogueras Formation, Celtiberia, Spain. The new taxon also includes a fragmentary spine and isolated scales from the Lower Devonian of northern Spain (Palencia and Cantabrian Mountains) and western France (Saint-Cenere) originally assigned to Machaeracanthus sp. The spines of M. goujeti n. sp. comprise two morphotypes in agreement with the morphofunctional model of a pair of pectoral spines articulating with the pectoral girdle already indicated for M. hunsrueckianum Sudkamp & Burrow, 2007, M. longaevus Eastman, 1907, and M. sulcatus Newberry, 1857. The morphology and size of the spines distinguish M. goujeti n. sp. from the coeval species M. bohemicus Barrande, 1872; the new species most closely resembles the younger species M. peracutus Newberry, 1857. The spines of M. goujeti n. sp. consist of trabecular an...