J. Neveling - Academia.edu (original) (raw)

Papers by J. Neveling

Research paper thumbnail of A new Triassic owenettid parareptile and the Mother of Mass Extinctions

Journal of Vertebrate Paleontology, 2003

... procolophonoid lineages. The specimen was collected from the farm Barendskraal in the South A... more ... procolophonoid lineages. The specimen was collected from the farm Barendskraal in the South African Karoo, the same locality that yielded the holotype of the basal procolophonoid Sauropareion anoplus (Modesto et al., 2001). It ...

Research paper thumbnail of Figure 13 in A new trirachodontid cynodont from the lower levels of the Burgersdorp Formation (Lower Triassic) of the Beaufort Group, South Africa and the cladistic relationships of Gondwanan gomphodonts

Figure 13. Majority-rule consensus tree of the analysis with characters having equal weights plot... more Figure 13. Majority-rule consensus tree of the analysis with characters having equal weights plotted against the geological time scale to indicate temporal distribution of the taxa included in the analysis (see Appendix 1). The geological time scale is based on Gradstein & Ogg (2004). Ans, Anisian; Crn, Carnian; E, Early; Ind, Induan; L, Late; Lad, Ladinian; M, Middle; Nor, Norian; Ol, Olenekian.

Research paper thumbnail of Figure 10 in A new trirachodontid cynodont from the lower levels of the Burgersdorp Formation (Lower Triassic) of the Beaufort Group, South Africa and the cladistic relationships of Gondwanan gomphodonts

Figure 10. Postcanine teeth of Langbergia modisei. A, third and fourth upper left postcanines of ... more Figure 10. Postcanine teeth of Langbergia modisei. A, third and fourth upper left postcanines of the holotype NMQR 3255 in occlusal view. Note the replacement of the sectorial teeth by a gomphodont. B, third and fourth lower left postcanines of NMQR 3256 in occlusal view. C, last three right sectorial upper postcanines of NMQR 3256 in labial view (see also Fig. 8A). D, left sectorial upper postcanine of NMQR 3255 in lingual view. aac, anterior accessory cusp; cc, cingular cusps; cec, central cusp; cr, crenulated ridge; lac, labial cusp; lic, lingual cusp; mc, main cusp; pac, posterior accessory cusp; sp., sectorial postcanine. Scale bars = 2 mm.

Research paper thumbnail of Figure 7 in A new trirachodontid cynodont from the lower levels of the Burgersdorp Formation (Lower Triassic) of the Beaufort Group, South Africa and the cladistic relationships of Gondwanan gomphodonts

Figure 7. Stereopair and interpretative drawing of the palate of NMQR 3251. Ec, ectopterygoid; in... more Figure 7. Stereopair and interpretative drawing of the palate of NMQR 3251. Ec, ectopterygoid; inf, incisive foramen; mpf, major palatine foramen; Mx, maxilla; Pa, palatine; pcf, paracanine fossa; Pmx, premaxilla; Pt, pterygoid; rc, replacement canine; V, vomer. Scale bar = 2 cm.

Research paper thumbnail of Figure 6 in A new trirachodontid cynodont from the lower levels of the Burgersdorp Formation (Lower Triassic) of the Beaufort Group, South Africa and the cladistic relationships of Gondwanan gomphodonts

Figure 6. Stereopair and interpretative drawing of NMQR 3255, holotype of Langbergia modisei, in ... more Figure 6. Stereopair and interpretative drawing of NMQR 3255, holotype of Langbergia modisei, in occipital view. Eo, exoccipital; pop, paroccipital process of the opistotic; oc, occipital condyle; Pp, postparietal; ptf, post-temporal foramen; qn, quadrate notch of the squamosal; So, supraoccipital; T, tabular; Sq, squamosal. Shading indicates the broken surface of the bone. Scale bar = 2 cm.

Research paper thumbnail of Figure 2 in A new trirachodontid cynodont from the lower levels of the Burgersdorp Formation (Lower Triassic) of the Beaufort Group, South Africa and the cladistic relationships of Gondwanan gomphodonts

Figure 2. Stereopair and interpretative drawing of NMQR 3255, holotype of Langbergia modisei, in ... more Figure 2. Stereopair and interpretative drawing of NMQR 3255, holotype of Langbergia modisei, in dorsal view. Ept, epipterygoid; L, lacrimal; Mx, maxilla; N, nasal; F, frontal; P, parietal; Pmx, premaxilla; Po, postorbital; Prf, prefrontal; Pro, prootic; Sq, squamosal; tf, trigeminal foramen (for maxillary and mandibular divisions of the trigeminal nerve). Note that bones in the facial region (maxillae, nasals, lacrimals, and prefrontals) are not in their original position. Shading indicates a broken portion (in the jugal) and sediment posteriorly of the postorbital bar. Scale bar = 3 cm.

Research paper thumbnail of Figure 11 in A new trirachodontid cynodont from the lower levels of the Burgersdorp Formation (Lower Triassic) of the Beaufort Group, South Africa and the cladistic relationships of Gondwanan gomphodonts

Figure 11. Upper postcanine morphology of the three South African trirachodontids. A, Langbergia.... more Figure 11. Upper postcanine morphology of the three South African trirachodontids. A, Langbergia. B, Trirachodon. C, Cricodon. The hatched pattern indicates wear. Modified from Abdala et al. (2005).

Research paper thumbnail of A new basal sauropodomorph dinosaur from the Early Jurassic of South Africa

Journal of Vertebrate Paleontology, 2011

ABSTRACT A new basal sauropodomorph dinosaur, Arcusaurus pereirabdalorum, sp. nov., is named and ... more ABSTRACT A new basal sauropodomorph dinosaur, Arcusaurus pereirabdalorum, sp. nov., is named and described on the basis of a partial, disarticulated but associated skull and dispersed cranial and postcranial elements from at least two individuals. Arcusaurus is part of a distinctive local fauna from the upper Elliot Formation (Lower Jurassic) in the Senekal District, Free State, South Africa. It can be diagnosed by various details of the premaxilla, nasal, and dentary in the skull and the shape of the distal caudal vertebrae. The taxon ...

Research paper thumbnail of Cynodonts from the Uppermost Burgersdorp Formation, South Africa, and their bearing on the biostratigraphy and correlation of the Triassic Cynognathus Assemblage Zone

Journal of Vertebrate Paleontology, 2005

ABSTRACT The Burgersdorp Formation in the Beaufort Group of the South African Karoo Basin records... more ABSTRACT The Burgersdorp Formation in the Beaufort Group of the South African Karoo Basin records a diverse and rich vertebrate fauna that is referred biostratigraphically to the Cynognathus Assemblage Zone. Recent collecting efforts, and taxonomic and ...

Research paper thumbnail of Latest Permian paleosols from Wapadsberg Pass, South Africa: Implications for Changhsingian climate

Geological Society of America Bulletin, 2014

Terrestrial settings preceding the end-Permian crisis are reported to trend toward increasingly d... more Terrestrial settings preceding the end-Permian crisis are reported to trend toward increasingly dry and arid conditions, resulting in landscape change and a shift in fl uvial architectures and regimes. Much of the latest Permian (Changhsingian) stratigraphic record in the Karoo Basin, South Africa, consists of paleosols, which record the physical conditions across time and space. Preboundary sequences at Wapadsberg Pass, Eastern Cape Province, provide insight into the climate regime that infl uenced paleosol formation at that time. A high-resolution sedimentological and geochemical study of two, stacked aggradational paleosols, in conjunction with stable isotope geochemical characterization of paleosol carbonate-cemented concretions over a 90 m section at this locality, demonstrates that these landscapes were predominantly wetland terrains without a demonstrable trend in increasing drying up to the Permian-Triassic boundary, as defi ned by vertebrates in the area. Two paleosols examined 70 m below the Permian-Triassic boundary are identifi ed as Protosols, and the former soil-air interface of each is marked by an autochthonous forestfl oor litter in which canopy leaves of Glossopteris and groundcover plants of Trizygia are preserved. Molecular weathering ratios (e.g., base loss, clayeyness, chemical index of alteration minus potassium [CIA-K], etc.) determined from these horizons are indicative of immature soil development under watersaturated conditions. Assuming that paleosol-matrix concentrations of trace elements are indicative of Permian soil-solution chem-istries, high concentrations of Ni, Cu, Ba, and Cr may have been growth-stress factors that may account for the small glossopterid leaf size in the megafl oras, in contrast to current models that implicate stress in response to climate change. Stable isotope δ 18 O and δ 13 C values are presented for micritic and microspar (<20 μm) calcite cements from carbonate nodules collected at 15 horizons through a 90 m stratigraphic interval up to, and including, the Permian-Triassic boundary. These isotopic ratios exhibit dissimilar trends. No clear trend exists in δ 18 O (Peedee belemnite [PDB] values range from-14.7‰ to-21.8‰). In contrast, a trend exists in δ 13 C values, where carbonate cements almost certainly precipitated under well-drained conditions in an interval that is 60 m below the Permian-Triassic boundary (-5.3‰), while δ 13 C values as low as-16.9‰, indicative of waterlogged conditions, begin 90 m below and continue up to the Permian-Triassic boundary. Hence, no evidence is found for a preboundary trend toward increasing aridity at this locality. The fi rst estimates of the latest Permian atmospheric pCO 2 from paleosols, based on coexisting calcite and organic matter δ 13 C values from paleosols that developed under well-drained conditions, provide a range of values from 900 to 1900, and 500 to 1300 ppmV, respectively, which are signifi cantly lower than the latest Early Permian, when terrestrial biome replacement is documented to have occurred.

Research paper thumbnail of Figure 12 in A new trirachodontid cynodont from the lower levels of the Burgersdorp Formation (Lower Triassic) of the Beaufort Group, South Africa and the cladistic relationships of Gondwanan gomphodonts

Figure 12. Majority-rule consensus tree of: A, 40 most-parsimonious trees obtained from the analy... more Figure 12. Majority-rule consensus tree of: A, 40 most-parsimonious trees obtained from the analysis with characters having equal weights (length = 103, consistency index for informative characters = 0.55, retention index = 0.71); B, four mostparsimonious trees obtained from the analysis using implied weights (total fit = 36.36; adjusted homoplasy = 8.64). The numbers indicate the frequency of clades in the fundamental trees. The nodes without a number indicate that the clades are present in all of the most-parsimonious trees of the analysis. The letters (a, b) are used to name the clades (see Appendix 4).

Research paper thumbnail of Figure 8 in A new trirachodontid cynodont from the lower levels of the Burgersdorp Formation (Lower Triassic) of the Beaufort Group, South Africa and the cladistic relationships of Gondwanan gomphodonts

Figure 8. Stereopair of NMQR 3251. A, last left postcanines in lateral view (anterior, bottom). B... more Figure 8. Stereopair of NMQR 3251. A, last left postcanines in lateral view (anterior, bottom). B, lower jaw in occlusal view. Note the replacement of the canine in the left ramus of the lower jaw. Scale bars = 2 cm.

Research paper thumbnail of Figure 5 in A new trirachodontid cynodont from the lower levels of the Burgersdorp Formation (Lower Triassic) of the Beaufort Group, South Africa and the cladistic relationships of Gondwanan gomphodonts

Figure 5. Stereopair and interpretative drawing of the lateral wall of the braincase in NMQR 3255... more Figure 5. Stereopair and interpretative drawing of the lateral wall of the braincase in NMQR 3255, holotype of Langbergia modisei. Ept, epipterygoid; otg, external orbitotemporal groove; pao, pila antotica of the prootic; P, parietal; Pro, prootic; Sq, squamosal; tf, trigeminal foramen. The dashed lines indicate broken and displaced surfaces of the epipterygoid. Shading indicates the broken surface of the prootic. Scale bar = 1 cm.

Research paper thumbnail of Figure 3 in A new trirachodontid cynodont from the lower levels of the Burgersdorp Formation (Lower Triassic) of the Beaufort Group, South Africa and the cladistic relationships of Gondwanan gomphodonts

Figure 3. Stereopair and interpretative drawing of NMQR 3255, holotype of Langbergia modisei, in ... more Figure 3. Stereopair and interpretative drawing of NMQR 3255, holotype of Langbergia modisei, in right lateral view. J, jugal; L, lacrimal; Mx, maxilla; N, nasal; F, frontal; P, parietal; Pmx, premaxilla; Po, postorbital; Prf, prefrontal; pps, posterodorsal process of the septomaxilla; smf, septomaxillary foramen; Sq, squamosal; ss, squamosal sulcus. Note that bones in the facial region (maxillae, nasals, lacrimals, and prefrontals) are not in their original position. Scale bar = 3 cm.

Research paper thumbnail of Figure 1 in A new trirachodontid cynodont from the lower levels of the Burgersdorp Formation (Lower Triassic) of the Beaufort Group, South Africa and the cladistic relationships of Gondwanan gomphodonts

Figure 1. Map with the location of the outcrops with remains of Langbergia modisei. The dark area... more Figure 1. Map with the location of the outcrops with remains of Langbergia modisei. The dark area in the inset map is enlarged to show the localities. 1, Palmiet Fontein 94, Tarkastad. 2, Moerbeidal 648, Rouxville. 3, Kaaimansgat 146, Rouxville. 4, Hugo's Kop 620, Rouxville. 5, Goedgedacht 15, Marquard. 6, Bosrand 12, Senekal. 7, Rexford Store 433, Bethlehem. 8, Langberg 556, Bethlehem. 9, Eerste Geluk 131, Bethlehem.

Research paper thumbnail of Figure 4 in A new trirachodontid cynodont from the lower levels of the Burgersdorp Formation (Lower Triassic) of the Beaufort Group, South Africa and the cladistic relationships of Gondwanan gomphodonts

Figure 4. Stereopair and interpretative drawing of NMQR 3255, holotype of Langbergia modisei, in ... more Figure 4. Stereopair and interpretative drawing of NMQR 3255, holotype of Langbergia modisei, in ventral view. Bo, basioccipital; ce, cavum epiptericum; Ec, ectopterygoid; fo, fenestra ovalis; inf, incisive foramen; jf, jugular foramen; J, jugal; Mx, maxilla; Pa, palatine; pcf, paracanine fossa; Pmx, premaxilla; pop, paroccipital process; Pt, pterygoid; Q, quadrate; V, vomer. Shading indicates a broken portion (in the pterygoid flanges) and sediment covering part of the basicranium and zygoma. Scale bar = 3 cm.

Research paper thumbnail of Figure 9 in A new trirachodontid cynodont from the lower levels of the Burgersdorp Formation (Lower Triassic) of the Beaufort Group, South Africa and the cladistic relationships of Gondwanan gomphodonts

Figure 9. Stereopair and interpretative drawing of NMQR 3256, in left lateral view. An, angular; ... more Figure 9. Stereopair and interpretative drawing of NMQR 3256, in left lateral view. An, angular; D, dentary; J, jugal; L, lacrimal; Mx, maxilla; N, nasal; P, parietal; Pmx, premaxilla; Po, postorbital; Prf, prefrontal; Smx, septomaxilla; Sq, squamosal; ss, squamosal sulcus. Scale bar = 2 cm.

Research paper thumbnail of implications for the stratigraphic ranges of early Triassic tetrapods

Rocks of the Beaufort Group (Karoo Supergroup) outcrop over approximately 300 000 km2 in South Af... more Rocks of the Beaufort Group (Karoo Supergroup) outcrop over approximately 300 000 km2 in South Africa (Smith 1990) and are renowned for their wealth of terres-trial tetrapod fossils, which have enabled the present

Research paper thumbnail of Permian-Triassic boundary in the Northwest Karoo Basin: Current stratigraphic placement, implications for basin development models, and search for evidence of impact

Catastrophic events and mass extinctions: impacts and beyond, 2002

ABSTRACT Recent geological and paleontological studies of the Permian-Triassic (P-Tr) boundary se... more ABSTRACT Recent geological and paleontological studies of the Permian-Triassic (P-Tr) boundary sequence in the northwest of the main Karoo basin of South Africa have shown that there is some ambiguity as to the exact placement of the contact. The change in fluvial ...

Research paper thumbnail of Isotopic evidence for the geographic origins and diet of the 36,000 year-old Hofmeyr skull

Research paper thumbnail of A new Triassic owenettid parareptile and the Mother of Mass Extinctions

Journal of Vertebrate Paleontology, 2003

... procolophonoid lineages. The specimen was collected from the farm Barendskraal in the South A... more ... procolophonoid lineages. The specimen was collected from the farm Barendskraal in the South African Karoo, the same locality that yielded the holotype of the basal procolophonoid Sauropareion anoplus (Modesto et al., 2001). It ...

Research paper thumbnail of Figure 13 in A new trirachodontid cynodont from the lower levels of the Burgersdorp Formation (Lower Triassic) of the Beaufort Group, South Africa and the cladistic relationships of Gondwanan gomphodonts

Figure 13. Majority-rule consensus tree of the analysis with characters having equal weights plot... more Figure 13. Majority-rule consensus tree of the analysis with characters having equal weights plotted against the geological time scale to indicate temporal distribution of the taxa included in the analysis (see Appendix 1). The geological time scale is based on Gradstein & Ogg (2004). Ans, Anisian; Crn, Carnian; E, Early; Ind, Induan; L, Late; Lad, Ladinian; M, Middle; Nor, Norian; Ol, Olenekian.

Research paper thumbnail of Figure 10 in A new trirachodontid cynodont from the lower levels of the Burgersdorp Formation (Lower Triassic) of the Beaufort Group, South Africa and the cladistic relationships of Gondwanan gomphodonts

Figure 10. Postcanine teeth of Langbergia modisei. A, third and fourth upper left postcanines of ... more Figure 10. Postcanine teeth of Langbergia modisei. A, third and fourth upper left postcanines of the holotype NMQR 3255 in occlusal view. Note the replacement of the sectorial teeth by a gomphodont. B, third and fourth lower left postcanines of NMQR 3256 in occlusal view. C, last three right sectorial upper postcanines of NMQR 3256 in labial view (see also Fig. 8A). D, left sectorial upper postcanine of NMQR 3255 in lingual view. aac, anterior accessory cusp; cc, cingular cusps; cec, central cusp; cr, crenulated ridge; lac, labial cusp; lic, lingual cusp; mc, main cusp; pac, posterior accessory cusp; sp., sectorial postcanine. Scale bars = 2 mm.

Research paper thumbnail of Figure 7 in A new trirachodontid cynodont from the lower levels of the Burgersdorp Formation (Lower Triassic) of the Beaufort Group, South Africa and the cladistic relationships of Gondwanan gomphodonts

Figure 7. Stereopair and interpretative drawing of the palate of NMQR 3251. Ec, ectopterygoid; in... more Figure 7. Stereopair and interpretative drawing of the palate of NMQR 3251. Ec, ectopterygoid; inf, incisive foramen; mpf, major palatine foramen; Mx, maxilla; Pa, palatine; pcf, paracanine fossa; Pmx, premaxilla; Pt, pterygoid; rc, replacement canine; V, vomer. Scale bar = 2 cm.

Research paper thumbnail of Figure 6 in A new trirachodontid cynodont from the lower levels of the Burgersdorp Formation (Lower Triassic) of the Beaufort Group, South Africa and the cladistic relationships of Gondwanan gomphodonts

Figure 6. Stereopair and interpretative drawing of NMQR 3255, holotype of Langbergia modisei, in ... more Figure 6. Stereopair and interpretative drawing of NMQR 3255, holotype of Langbergia modisei, in occipital view. Eo, exoccipital; pop, paroccipital process of the opistotic; oc, occipital condyle; Pp, postparietal; ptf, post-temporal foramen; qn, quadrate notch of the squamosal; So, supraoccipital; T, tabular; Sq, squamosal. Shading indicates the broken surface of the bone. Scale bar = 2 cm.

Research paper thumbnail of Figure 2 in A new trirachodontid cynodont from the lower levels of the Burgersdorp Formation (Lower Triassic) of the Beaufort Group, South Africa and the cladistic relationships of Gondwanan gomphodonts

Figure 2. Stereopair and interpretative drawing of NMQR 3255, holotype of Langbergia modisei, in ... more Figure 2. Stereopair and interpretative drawing of NMQR 3255, holotype of Langbergia modisei, in dorsal view. Ept, epipterygoid; L, lacrimal; Mx, maxilla; N, nasal; F, frontal; P, parietal; Pmx, premaxilla; Po, postorbital; Prf, prefrontal; Pro, prootic; Sq, squamosal; tf, trigeminal foramen (for maxillary and mandibular divisions of the trigeminal nerve). Note that bones in the facial region (maxillae, nasals, lacrimals, and prefrontals) are not in their original position. Shading indicates a broken portion (in the jugal) and sediment posteriorly of the postorbital bar. Scale bar = 3 cm.

Research paper thumbnail of Figure 11 in A new trirachodontid cynodont from the lower levels of the Burgersdorp Formation (Lower Triassic) of the Beaufort Group, South Africa and the cladistic relationships of Gondwanan gomphodonts

Figure 11. Upper postcanine morphology of the three South African trirachodontids. A, Langbergia.... more Figure 11. Upper postcanine morphology of the three South African trirachodontids. A, Langbergia. B, Trirachodon. C, Cricodon. The hatched pattern indicates wear. Modified from Abdala et al. (2005).

Research paper thumbnail of A new basal sauropodomorph dinosaur from the Early Jurassic of South Africa

Journal of Vertebrate Paleontology, 2011

ABSTRACT A new basal sauropodomorph dinosaur, Arcusaurus pereirabdalorum, sp. nov., is named and ... more ABSTRACT A new basal sauropodomorph dinosaur, Arcusaurus pereirabdalorum, sp. nov., is named and described on the basis of a partial, disarticulated but associated skull and dispersed cranial and postcranial elements from at least two individuals. Arcusaurus is part of a distinctive local fauna from the upper Elliot Formation (Lower Jurassic) in the Senekal District, Free State, South Africa. It can be diagnosed by various details of the premaxilla, nasal, and dentary in the skull and the shape of the distal caudal vertebrae. The taxon ...

Research paper thumbnail of Cynodonts from the Uppermost Burgersdorp Formation, South Africa, and their bearing on the biostratigraphy and correlation of the Triassic Cynognathus Assemblage Zone

Journal of Vertebrate Paleontology, 2005

ABSTRACT The Burgersdorp Formation in the Beaufort Group of the South African Karoo Basin records... more ABSTRACT The Burgersdorp Formation in the Beaufort Group of the South African Karoo Basin records a diverse and rich vertebrate fauna that is referred biostratigraphically to the Cynognathus Assemblage Zone. Recent collecting efforts, and taxonomic and ...

Research paper thumbnail of Latest Permian paleosols from Wapadsberg Pass, South Africa: Implications for Changhsingian climate

Geological Society of America Bulletin, 2014

Terrestrial settings preceding the end-Permian crisis are reported to trend toward increasingly d... more Terrestrial settings preceding the end-Permian crisis are reported to trend toward increasingly dry and arid conditions, resulting in landscape change and a shift in fl uvial architectures and regimes. Much of the latest Permian (Changhsingian) stratigraphic record in the Karoo Basin, South Africa, consists of paleosols, which record the physical conditions across time and space. Preboundary sequences at Wapadsberg Pass, Eastern Cape Province, provide insight into the climate regime that infl uenced paleosol formation at that time. A high-resolution sedimentological and geochemical study of two, stacked aggradational paleosols, in conjunction with stable isotope geochemical characterization of paleosol carbonate-cemented concretions over a 90 m section at this locality, demonstrates that these landscapes were predominantly wetland terrains without a demonstrable trend in increasing drying up to the Permian-Triassic boundary, as defi ned by vertebrates in the area. Two paleosols examined 70 m below the Permian-Triassic boundary are identifi ed as Protosols, and the former soil-air interface of each is marked by an autochthonous forestfl oor litter in which canopy leaves of Glossopteris and groundcover plants of Trizygia are preserved. Molecular weathering ratios (e.g., base loss, clayeyness, chemical index of alteration minus potassium [CIA-K], etc.) determined from these horizons are indicative of immature soil development under watersaturated conditions. Assuming that paleosol-matrix concentrations of trace elements are indicative of Permian soil-solution chem-istries, high concentrations of Ni, Cu, Ba, and Cr may have been growth-stress factors that may account for the small glossopterid leaf size in the megafl oras, in contrast to current models that implicate stress in response to climate change. Stable isotope δ 18 O and δ 13 C values are presented for micritic and microspar (<20 μm) calcite cements from carbonate nodules collected at 15 horizons through a 90 m stratigraphic interval up to, and including, the Permian-Triassic boundary. These isotopic ratios exhibit dissimilar trends. No clear trend exists in δ 18 O (Peedee belemnite [PDB] values range from-14.7‰ to-21.8‰). In contrast, a trend exists in δ 13 C values, where carbonate cements almost certainly precipitated under well-drained conditions in an interval that is 60 m below the Permian-Triassic boundary (-5.3‰), while δ 13 C values as low as-16.9‰, indicative of waterlogged conditions, begin 90 m below and continue up to the Permian-Triassic boundary. Hence, no evidence is found for a preboundary trend toward increasing aridity at this locality. The fi rst estimates of the latest Permian atmospheric pCO 2 from paleosols, based on coexisting calcite and organic matter δ 13 C values from paleosols that developed under well-drained conditions, provide a range of values from 900 to 1900, and 500 to 1300 ppmV, respectively, which are signifi cantly lower than the latest Early Permian, when terrestrial biome replacement is documented to have occurred.

Research paper thumbnail of Figure 12 in A new trirachodontid cynodont from the lower levels of the Burgersdorp Formation (Lower Triassic) of the Beaufort Group, South Africa and the cladistic relationships of Gondwanan gomphodonts

Figure 12. Majority-rule consensus tree of: A, 40 most-parsimonious trees obtained from the analy... more Figure 12. Majority-rule consensus tree of: A, 40 most-parsimonious trees obtained from the analysis with characters having equal weights (length = 103, consistency index for informative characters = 0.55, retention index = 0.71); B, four mostparsimonious trees obtained from the analysis using implied weights (total fit = 36.36; adjusted homoplasy = 8.64). The numbers indicate the frequency of clades in the fundamental trees. The nodes without a number indicate that the clades are present in all of the most-parsimonious trees of the analysis. The letters (a, b) are used to name the clades (see Appendix 4).

Research paper thumbnail of Figure 8 in A new trirachodontid cynodont from the lower levels of the Burgersdorp Formation (Lower Triassic) of the Beaufort Group, South Africa and the cladistic relationships of Gondwanan gomphodonts

Figure 8. Stereopair of NMQR 3251. A, last left postcanines in lateral view (anterior, bottom). B... more Figure 8. Stereopair of NMQR 3251. A, last left postcanines in lateral view (anterior, bottom). B, lower jaw in occlusal view. Note the replacement of the canine in the left ramus of the lower jaw. Scale bars = 2 cm.

Research paper thumbnail of Figure 5 in A new trirachodontid cynodont from the lower levels of the Burgersdorp Formation (Lower Triassic) of the Beaufort Group, South Africa and the cladistic relationships of Gondwanan gomphodonts

Figure 5. Stereopair and interpretative drawing of the lateral wall of the braincase in NMQR 3255... more Figure 5. Stereopair and interpretative drawing of the lateral wall of the braincase in NMQR 3255, holotype of Langbergia modisei. Ept, epipterygoid; otg, external orbitotemporal groove; pao, pila antotica of the prootic; P, parietal; Pro, prootic; Sq, squamosal; tf, trigeminal foramen. The dashed lines indicate broken and displaced surfaces of the epipterygoid. Shading indicates the broken surface of the prootic. Scale bar = 1 cm.

Research paper thumbnail of Figure 3 in A new trirachodontid cynodont from the lower levels of the Burgersdorp Formation (Lower Triassic) of the Beaufort Group, South Africa and the cladistic relationships of Gondwanan gomphodonts

Figure 3. Stereopair and interpretative drawing of NMQR 3255, holotype of Langbergia modisei, in ... more Figure 3. Stereopair and interpretative drawing of NMQR 3255, holotype of Langbergia modisei, in right lateral view. J, jugal; L, lacrimal; Mx, maxilla; N, nasal; F, frontal; P, parietal; Pmx, premaxilla; Po, postorbital; Prf, prefrontal; pps, posterodorsal process of the septomaxilla; smf, septomaxillary foramen; Sq, squamosal; ss, squamosal sulcus. Note that bones in the facial region (maxillae, nasals, lacrimals, and prefrontals) are not in their original position. Scale bar = 3 cm.

Research paper thumbnail of Figure 1 in A new trirachodontid cynodont from the lower levels of the Burgersdorp Formation (Lower Triassic) of the Beaufort Group, South Africa and the cladistic relationships of Gondwanan gomphodonts

Figure 1. Map with the location of the outcrops with remains of Langbergia modisei. The dark area... more Figure 1. Map with the location of the outcrops with remains of Langbergia modisei. The dark area in the inset map is enlarged to show the localities. 1, Palmiet Fontein 94, Tarkastad. 2, Moerbeidal 648, Rouxville. 3, Kaaimansgat 146, Rouxville. 4, Hugo's Kop 620, Rouxville. 5, Goedgedacht 15, Marquard. 6, Bosrand 12, Senekal. 7, Rexford Store 433, Bethlehem. 8, Langberg 556, Bethlehem. 9, Eerste Geluk 131, Bethlehem.

Research paper thumbnail of Figure 4 in A new trirachodontid cynodont from the lower levels of the Burgersdorp Formation (Lower Triassic) of the Beaufort Group, South Africa and the cladistic relationships of Gondwanan gomphodonts

Figure 4. Stereopair and interpretative drawing of NMQR 3255, holotype of Langbergia modisei, in ... more Figure 4. Stereopair and interpretative drawing of NMQR 3255, holotype of Langbergia modisei, in ventral view. Bo, basioccipital; ce, cavum epiptericum; Ec, ectopterygoid; fo, fenestra ovalis; inf, incisive foramen; jf, jugular foramen; J, jugal; Mx, maxilla; Pa, palatine; pcf, paracanine fossa; Pmx, premaxilla; pop, paroccipital process; Pt, pterygoid; Q, quadrate; V, vomer. Shading indicates a broken portion (in the pterygoid flanges) and sediment covering part of the basicranium and zygoma. Scale bar = 3 cm.

Research paper thumbnail of Figure 9 in A new trirachodontid cynodont from the lower levels of the Burgersdorp Formation (Lower Triassic) of the Beaufort Group, South Africa and the cladistic relationships of Gondwanan gomphodonts

Figure 9. Stereopair and interpretative drawing of NMQR 3256, in left lateral view. An, angular; ... more Figure 9. Stereopair and interpretative drawing of NMQR 3256, in left lateral view. An, angular; D, dentary; J, jugal; L, lacrimal; Mx, maxilla; N, nasal; P, parietal; Pmx, premaxilla; Po, postorbital; Prf, prefrontal; Smx, septomaxilla; Sq, squamosal; ss, squamosal sulcus. Scale bar = 2 cm.

Research paper thumbnail of implications for the stratigraphic ranges of early Triassic tetrapods

Rocks of the Beaufort Group (Karoo Supergroup) outcrop over approximately 300 000 km2 in South Af... more Rocks of the Beaufort Group (Karoo Supergroup) outcrop over approximately 300 000 km2 in South Africa (Smith 1990) and are renowned for their wealth of terres-trial tetrapod fossils, which have enabled the present

Research paper thumbnail of Permian-Triassic boundary in the Northwest Karoo Basin: Current stratigraphic placement, implications for basin development models, and search for evidence of impact

Catastrophic events and mass extinctions: impacts and beyond, 2002

ABSTRACT Recent geological and paleontological studies of the Permian-Triassic (P-Tr) boundary se... more ABSTRACT Recent geological and paleontological studies of the Permian-Triassic (P-Tr) boundary sequence in the northwest of the main Karoo basin of South Africa have shown that there is some ambiguity as to the exact placement of the contact. The change in fluvial ...

Research paper thumbnail of Isotopic evidence for the geographic origins and diet of the 36,000 year-old Hofmeyr skull