Palaeontologia africana
Permanent URI for this communityhttps://wiredspace.wits.ac.za/handle/10539/13253
ISSN (print): 0078-8554
ISSN (electronic): 2410-4418
For queries regarding content of Palaeontologia africana collections please contact Jonah Choiniere by email : jonah.choiniere@wits.ac.za or Tel : 011 717 6684
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Item A new actinopterygian fish species from the Late Permian Beaufort Group, South Africa(Bernard Price Institute for Palaeontological Research, 2001) Bender, PatrickA new genus and species of actinopterygian (ray-finned) fish, Bethesdaichthys kitchingi, is described from the Tatarian, Late Permian, Lower Beaufort Group of South Africa. Bethesdaichthys is presently known from three localities, two in the New Bethesda and one in the Victoria West districts of the Karoo region respectively. The fossils were recovered from within the Abrahamskraal Formation Tapinocephalus Assemblage Zone at the Victoria West locality, and from an uncertain Formation possibly closely equivalent to the Balfour Formation, within the Dicynodon Assemblage Zone at the New Bethesda sites. Bethesdaichthys kitchingi is a fusiform fish, up to approximately 300mm in total length, with the skull displaying a moderately oblique suspensorium, and a maxilla with a large sub-rectangular postorbital blade. Furthermore there is a complex of four suborbital bones adjacent to the orbit. The pectoral fin is large relative to body size and the tail is heterocercal with an elongate tapered dorsal body lobe. The anterior midflank scales in particular exhibit a distinctive dermal ornamentation consisting of numerous ganoine ridges. The phylogenetics and interrelationships of Bethesdaichthys kitchingiare examined. It appears to exhibit a relatively conservative morphology similar to that found in possibly related Carboniferous taxa such as the South African taxa Australichthys and Willomorichthys. Bethesdaichthys kitchingiis derived relative to stem-actinopterans such as the Howqualepis and Mimia, and also derived relative to southern African Palaeozoic actinoptyerygians such as Mentzichthys jubbi; and Namaichthys schroeden; but basal to stemneopterygians such as Australosomus, Perleldus and Saurichthys.Item A new late Permian ray-finned (actinopterygian) fish from the Beaufort Group, South Africa(Bernard Price Institute for Palaeontological Research, 2002) Bender, PatrickA new genus and species of actinopterygian (ray-finned) fish, Kompasia delaharpei, is described from Late Permian (Tatarian) fluvio-lacustrine, siltstone dominated deposits within the lower Beaufort Group of South Africa. It is currently known from two localities on adjoining farms, Wilgerbosch and Ganora, both in the New Bethesda district of the Eastern Cape Karoo region. The fossils were recovered from an uncertain formation, possibly closely equivalent to the Balfour Formation, within the Dicynodon Assemblage Zone. Kompasia delaharpei differs from previously described early actinopterygians, including the recently described new lower Beaufort Group taxon Bethesdaichthys kitchingi, on the basis of a combination of skull and post cranial characters. The genus is characterised by: a uniquely shaped subrectangular posterior blade of the maxilla, a shortened dorsal limb of the preopercular, and a dermopterotic and dermosphenotic contacting the nasal; furthermore, the subopercular is equal to or longer than the opercular, the dorsal fin is situated in the posterior third of the body, slightly behind the position of the anal fin, and the anterior midflank scales exhibit a smooth dermal pattern or surface, with a number of faint ganoine ridges present parallel to the posterior and ventral scale margins. Kompasia appears to exhibit a relatively conservative morphology similar to that in the lower Beaufort Group taxon Bethesdaichthys kitchingi. As such, Kompasia is derived relative to stem-actinopterans such as Howqualepis, Mimia and Moythomasia, and also derived relative to earlier southern African Palaeozoic actinopterygians such as Mentzichthys jubbi and Namaichthys schroederi, but basal to stem-neopterygians such as Australosomus and Saurichthys.Item A new deep-bodied Late Permian actinopterygian fish from the Beaufort Group, South Africa(BERNARD PRICE INSTITUTE FOR PALAEONTOLOGICAL RESEARCH, 2005) Bender, PatrickAnew genus of actinopterygian (ray-finned) fish, Blourugia seeleyi is described from Late Permian (Tatarian) fluvio-lacustrine, siltstone dominated deposits within the lower Beaufort Group of South Africa. It was originally provisionally assigned to the globally known genus Atherstonia by Woodward (1893), but indications are that the genus is distinct from Atherstonia on the basis of its deep-bodied form and the associated skull characters; thus Blourugia seeleyi is placed in Gardiner&Schaeffer’s (1989) Platysomus Group. The new genus is characterized by a uniquely shaped prominent high triangular posterior blade of the maxilla, dermosphenotic triangular shaped, pointed marginal teeth, 8–10 branchiostegal rays, flank scales that exhibit a well-developed dermal ornamentation consisting of numerous transverse ganoine ridges, and the presence of a dermopterotic that contacts the nasal. Blourugia appears to be a primitive deep-bodied form, basal to lower actinopterygian deep-bodied forms such as Adroichthys, Amphicentrum, Cheirodopsis, Paramesolepis and Platysomus. As a member of Gardiner & Schaeffer’s Platysomus Group, it is therefore derived relative to stem-actinopterans such as Howqualepis, Mimia and Moythomasia, and also derived relative to earlier southern African Palaeozoic actinopterygians such as Atherstonia scutata, Mentzichthys jubbi, Namaichthys schroederi and the newly/recently described lower Beaufort Group taxa Bethesdaichthys kitchingi and Kompasia delaharpei, but basal to stem-neopterygians such as Australosomus and Saurichthys.