Vertebrate assemblages from the north-central Main Karoo Basin, South Africa, and their implications for mid-Permian biogeography

Abstract

The rich fossil vertebrate record from the Beaufort Group, Main Karoo Basin, provides a global standard for mid‐Permian to Mid‐Triassic continental faunas. However, recent studies have demonstrated variability in the composition of contemporaneous faunas across Gondwana. This raises the question of how much the vertebrate faunas differ within the Karoo, where the taxonomic composition of vertebrate assemblage zones (AZs) is mostly considered to be uniform. Although fossil material is known from across the outcrop of the Beaufort Group, the lowest Beaufort strata have received little attention, particularly north of S31°10′. Here, we report two fossil tetrapod assemblages from the lowest Beaufort Group in the southern Free State Province, which represent the northernmost point at which the lowest Beaufort has been targeted for collecting. The lower assemblage is characterized by an abundance of the small dicynodont Eosimops and can thus be attributed to the Tapinocephalus AZ (Guadalupian), but the absence of dinocephalian or pareiasaurian material is unlike contemporaneous assemblages found further south. This suggests that the Tapinocephalus AZ was not uniform across the entire basin and highlights that the abundance, distribution and taxonomic composition of Karoo biozones may vary more than currently appreciated. The upper assemblage, characterized by the dicynodonts Oudenodon, Aulacephalodon and Dinanomodon, is attributable to the upper Cistecephalus AZ to lower Daptocephalus AZ. The juxtaposition of the lower Tapinocephalus AZ and upper Cistecephalus\lower Daptocephalus AZ in the southern Free State implies a stratigraphic gap from the Middle to Late Permian of up to 6 million years.

A new tusked cistecephalid dicynodont (Therapsida, Anomodontia) from the upper Permian upper Madumabisa Mudstone Formation, Luangwa Basin, Zambia

“…2018; Groenewald et al . 2019) and synthesis of data from South Africa, Tanzania and Zambia are beginning to facilitate a nuanced consideration of Permian regional biogeography in southern Gondwana. With further exploration of other basins in this area, such as the Metangula Graben of Mozambique (Castanhinha et al .…”

“…Therefore, even though South African and Zambian tetrapod communities appear to have been part of the same general biome during the mid-late Permian (Bernardi et al 2017), there was room for fine-scale variations in faunal composition to arise due to factors like minor environmental differences among areas, differing degrees of connectedness among basins, and the effects of particular ecologies, such as the tendency for fossorial taxa to develop allopatric distributions. New investigations of distribution patterns in the main Karoo Basin (Brocklehurst et al 2018;Groenewald et al 2019) and synthesis of data from South Africa, Tanzania and Zambia are beginning to facilitate a nuanced consideration of Permian regional biogeography in southern Gondwana. With further exploration of other basins in this area, such as the Metangula Graben of Mozambique (e.g.…”

Unique trackway on Permian Karoo shoreline provides evidence of temnospondyl locomotory behaviour

“…Named in honour of the late Mr Dave Green, who discovered this remarkable site and had a passion for palaeontology, the Dave Green palaeosurface (S28.967122˚, E29.987366˚) is located along a tributary of the Rensburgspruit on the farm Van der Merwe's Kraal 972, approximately 10 km northeast of the town Estcourt in KwaZulu-Natal Province, South Africa (Figs 1 and 2). The region spans the Ecca-Beaufort transition and is primarily underlain by late Permian (Changhsingian) siliciclastic deposits of the Waterford and Balfour formations that are intruded by lower Jurassic dolerite dykes and sills [32][33][34][35][36][37]. The Dave Green palaeosurface covers an area of approximately 600 m 2 and is situated in the upper Waterford Formation, immediately below the Ecca-Beaufort contact, which records the transition from marine/ lacustrine to fluvial environmental conditions [31,[34][35][36][37].…”

“…The region spans the Ecca-Beaufort transition and is primarily underlain by late Permian (Changhsingian) siliciclastic deposits of the Waterford and Balfour formations that are intruded by lower Jurassic dolerite dykes and sills [32][33][34][35][36][37]. The Dave Green palaeosurface covers an area of approximately 600 m 2 and is situated in the upper Waterford Formation, immediately below the Ecca-Beaufort contact, which records the transition from marine/ lacustrine to fluvial environmental conditions [31,[34][35][36][37].…”

“…In the southern Karoo Basin, the Waterford Formation constitutes the uppermost Ecca Group [38][39][40][41][42][43], but has recently been shown to also be present in the north of the basin, where it gradationally overlies the Volksrust or Tierberg formations [37]. This diagnostic and easily recognisable formation, which incorporates strata previously assigned to the upper Volksrust and/or conformably overlying lower Balfour Formation (including the now defunct Normandien and Estcourt formations [36,37]), is characterized as being generally arenaceous in nature, generally ripple-marked, as well as containing rhythmically-bedded carbonaceous shale and ubiquitous soft sediment deformation structures (Fig 3).…”