Palaeontologia africana

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A new actinopterygian fish species from the Late Permian Beaufort Group, South Africa
(Bernard Price Institute for Palaeontological Research, 2001) Bender, Patrick
A 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.
A dicynodont trackway from the Cistecephalus Assemblage Zone in the Karoo, East of Graaff-Reinet, South Africa
(Bernard Price Institute for Palaeontological Research, 2002) de Klerk, William J
This paper reports a partially exposed late Permian palaeosurface with preserved vertebrate tracks at the "Asante Sana" private game reserve in the vicinity of Petersburg, 46km east of Graaff-Reinet. Excavation of the palaeosurface over an area of 34m2 revealed clear footprints and trackways of six large tetrapods that walked in a westerly direction across a semi-consolidated muddy substrate in the distal floodplain area of a large fluvial system. Clear heteropodous impressions of the footpads and individual toes and claws are preserved as concave epirelief moulds. It is concluded that these fossil tracks were made by a group of therapsids, specifically a group of large dicynodonts, possibly Aulacephalodon. The tracks are here assigned to the ichnospecies Dicynodontipus icelsi sp. nov. A continuous trackway and numerous less distinct individual prints and markings made by smaller tetrapods are also preserved on the palaeosurface. It is probable that these tracks were left by Diictodon, a small common dicynodont of the time.
A new cynodont record from the Tropidostoma Assemblage Zone of the Beaufort Group: implications for the early evolution of cynodonts in South Africa
(Bernard Price Institute for Palaeontological Research, University of the Witwatersrand, 2008-04) Botha-Brink, J.; Abdala, F.
A new specimen of cynodont has been recovered from the lower Upper Permian levels of the Tropidostoma Assemblage Zone of the South African Karoo Basin. A series of characters, including the presence of an interpterygoid opening, triconodont postcanine teeth, which are circular in crown view, a probable lingual cingulum, and most significantly, the presence of a masseteric fossa high on the coronoid process, allows this specimen to be assigned to the Procynosuchidae. However, unlike most procynosuchids, precanine teeth are absent and the incisors are represented by four left and five right upper and probably, three lower teeth. Considering the small size of the new specimen from the Tropidostoma Assemblage Zone we identify it as a juvenile Procynosuchus delaharpeae, the only species currently recognized in the genus. The low number of incisors and absence of precanines in this specimen are interpreted as ontogenetic variation (i.e. juvenile characters). This discovery extends the biostratigraphic range of Procynosuchus, as it is now recorded in three assemblage zones, indicating that this taxon is the longest-lived cynodont in the Karoo Basin. The new specimen of Procynosuchus and the recently described Charassognathus gracilis, are the oldest global records of cynodonts, and indicate an earlier initial radiation of this lineage than was previously thought.

Palaeontologia africana

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