A new deep-bodied Late Permian actinopterygian fish from the Beaufort Group, South Africa

摘要

Anew genus of actinopterygian (ray-finned) fish, Blourugia seeleyi is described from Late Permian (Tatarian) fluvio-lacustrine, siltstone dominateduddeposits within the lower Beaufort Group of South Africa. It was originally provisionally assigned to the globally knownudgenus Atherstonia by Woodward (1893), but indications are that the genus is distinct from Atherstonia on the basis of its deep-bodied formudand the associated skull characters; thus Blourugia seeleyi is placed in Gardiner&Schaeffer’s (1989) Platysomus Group. The new genus isudcharacterized by a uniquely shaped prominent high triangular posterior blade of the maxilla, dermosphenotic triangular shaped,udpointed marginal teeth, 8–10 branchiostegal rays, flank scales that exhibit a well-developed dermal ornamentation consisting of numerousudtransverse ganoine ridges, and the presence of a dermopterotic that contacts the nasal. Blourugia appears to be a primitiveuddeep-bodied form, basal to lower actinopterygian deep-bodied forms such as Adroichthys, Amphicentrum, Cheirodopsis, Paramesolepis andudPlatysomus. As a member of Gardiner & Schaeffer’s Platysomus Group, it is therefore derived relative to stem-actinopterans such asudHowqualepis, Mimia and Moythomasia, and also derived relative to earlier southern African Palaeozoic actinopterygians such asudAtherstonia scutata, Mentzichthys jubbi, Namaichthys schroederi and the newly/recently described lower Beaufort Group taxaudBethesdaichthys kitchingi and Kompasia delaharpei, but basal to stem-neopterygians such as Australosomus and Saurichthys.