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Palaeoworld 17 (2008) 126–134

Research paper New procolophonid from the (Lower ) of the South African Juan Carlos Cisneros ∗ Bernard Price Institute for Palaeontological Research, University of the , Private Bag 3 WITS 2050, Johannesburg, Received 19 December 2007; received in revised form 1 May 2008; accepted 19 June 2008 Available online 27 June 2008

Abstract A new procolophonid reptile, Kitchingnathus untabeni n. gen. et n. sp., is described from the uppermost strata of the Assemblage Zone of the Karoo Basin, South Africa. The new taxon co-occurs with the well-known trigoniceps. The most distinctive feature of the new taxon is the presence of numerous small bicuspid molariforms in both the maxilla and the dentary. A phylogenetic analysis indicates that Kitchingnathus occupies a basal position among procolophonids. Character optimisation suggests that bicuspid teeth were acquired independently by the new taxon, and originated twice in procolophonid evolution. © 2008 Nanjing Institute of Geology and Palaeontology, CAS. Published by Elsevier Ltd. All rights reserved.

Keywords: Parareptiles; Procolophonids; Lystrosaurus Assemblage Zone; Triassic; South Africa

1. Introduction and USA (Sues et al., 2000; Cisneros and Schultz, 2003; Fraser et al., 2005). The Lystrosaurus Assemblage Zone (AZ) of In recent years, renewed attention has been given to the the Karoo Basin is characterised by relatively low of the Lystrosaurus AZ, resulting in the description diversity and the dominance of the dicynodont Lystrosaurus of the new procolophonoids kitchingorum (Reisz and (Kitching, 1977). Collecting in the Lystrosaurus AZ (Fig. 1A) Scott, 2002), Saurodektes rogersorum (Modesto et al., 2003), has traditionally been neglected due to the monotony of seca (Gow, 2000) and Sauropareion anoplus (Modesto Lystrosaurus findings (Kitching, 1977), a that comprises et al., 2001), and probable new temnospondyl amphibians up to 95% of the vertebrates in this horizon (Groenewald and (Damiani et al., 2000; Damiani and Welman, 2001). Gow (1977) Kitching, 1995). The procolophonoid Procolophon is also found mentioned a procolophonid specimen from the Lystrosaurus AZ in this biozone, occurring in isolated but usually large concen- that somehow differed from the genus Procolophon in the den- trations (Groenewald and Kitching, 1995). Procolophonoids are tition. However, Gow (1977) concluded that this specimen was the only of parareptiles that survived the Permo-Triassic a juvenile Procolophon and the differences with other spec- event and constitute part of the Early Triassic recovery imens were due to ontogeny. Gow (2000) changed his view fauna of the Karoo Basin (Fig. 1B; Modesto et al., 2001; Smith and stated the possibility that the could represent a new and Botha, 2005; Botha and Smith, 2006; Botha et al., 2007). taxon. Based on this specimen, a new genus and of basal The group radiated throughout Pangaea, and its last members procolophonid is described herein. are known from Upper Triassic rocks in Brazil, Britain, Canada

1.1. Institutional abbreviations

AMNH, American Museum of Natural History, New York; ∗ Present address: Departamento de Paleontologia e Estratigrafia, Universi- dade Federal do Rio Grande do Sul, Av. Bento Gonc¸alves 9500, Porto Alegre, BP, Bernard Price Institute for Palaeontological Research, CP 15001, 91540-000, Brazil. Tel.: +55 51 3308 6385; fax: +55 51 3308 7302. Johannesburg; NM, National Museum, Bloemfontein; SAM, E-mail address: [email protected]. Iziko, South African Museum, Cape Town.

1871-174X/$ – see front matter © 2008 Nanjing Institute of Geology and Palaeontology, CAS. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.palwor.2008.06.003 J.C. Cisneros / Palaeoworld 17 (2008) 126–134 127

Fig. 1. (A) Map of South Africa and Lesotho showing the location of the type locality (Hobbs Hill) of Kitchingnathus untabeni n. gen. et n. sp. The outcrops that yield Lystrosaurus Assemblage Zone fauna are represented in dark grey (after Groenewald and Kitching, 1995). (B) Stratigraphic chart showing the placement of South African procolophonoids (owenettids and procolophonids) in the geologic time. From left to right: periods, epochs, Karoo assemblage zones, Karoo formations, and taxa. Bars represent taxon ranges and solid circles indicate single specimen occurrences. The interval where the abundance of Procolophon trigoniceps is anomalously high (Neveling, 2004; Botha and Smith, 2006) is represented by a solid box. Owenettids are followed by an asterisk. Taxon ranges and occurrences after Neveling (2004), Botha and Smith (2006), Botha et al. (2007), Abdala et al. (2006) and Cisneros (2008b). Abbreviations: Chang., Changsingian; Ciste., Cistecephalus; Mid., ; P-Tr, -Triassic Boundary; Wuchiaping., .

2. Systematic palaeontology niceps specimens collected during field trips led by James W. Kitching in 1952 and 1966. Kitching (1977) assigned the fossil- Olson, 1947 iferous horizons of this locality to the uppermost Lystrosaurus Romer, 1956 AZ sandstones. The matrix that holds BP/1/1187 is bright red Cope, 1889 sandstone, characteristic of the middle-upper Katberg Formation and lowermost Burgersdorp Formation (Johann Neveling, pers. comm., 2006). Kitchingnathus untabeni was most likely col- Kitchingnathus n. gen. lected in the middle or upper horizons of the Katberg Formation Etymology : In honour of the late James W. Kitching, a prominent , a stratigraphic assessment that is consistent with the presence South African palaeontologist and collector of the specimen; and of the index genus Procolophon at the locality. The occurrence gnathus from the Greek , mandible. of Procolophon in South Africa is restricted to the interval Diagnosis : As for the type and only known species. between the middle part of the Katberg Formation and the lower- Type species Kitchingnathus untabeni : n. sp. most Burgersdorp Formation (Neveling, 2004; Smith and Botha, 2005; Botha and Smith, 2006). Kitchingnathus untabeni n. sp. Diagnosis: of the new taxon include: (1) At (Figs. 2 and 3) least nine upper and eight lower, chisel-like, small bicuspid v. 1977 Procolophon trigoniceps Gow, p. 701, text-fig. 6. molariforms, with labial cusps taller and thinner than lingual Etymology: An isiZulu term meaning “from the hill”, a reference cusps; and (2) a long posterior process of the maxilla that extends to the locality where the fossil was collected. along the rim of the subtemporal emargination as much as the Types: Holotype, BP/1/1187. A partial skeleton, in the collection quadratojugal. of the Bernard Price Institute for Palaeontological Research, Remarks: The new taxon possesses the highest number of bicus- University of the Witwatersrand, Johannesburg. Collected by pid teeth reported for a procolophonid. In Phaanthosaurus James W. Kitching in October 1952. (Contritosaurus) from the Lower Triassic of Russia, a similar Locality and horizon: Hobbs Hill (Windvogelsberg), west of count of bicuspid teeth (up to eight) is recorded in the max- Cathcart, Eastern Cape Province, South Africa; middle-upper illa. However, this form can readily be distinguished from the Katberg Formation, , , upper- new taxon in having a deeper snout and short upper incisiforms most Lystrosaurus AZ (Kitching, 1977), late Early Triassic which do not surpass the height of the molariforms, and by the (Olenekian). Besides the holotype of Kitchingnathus untabeni, absence of lower bicuspid teeth. The new taxon differs from the locality Hobbs Hill has yielded several Procolophon trigo- Sauropareion anoplus also by having a broader subtemporal 128 J.C. Cisneros / Palaeoworld 17 (2008) 126–134 emargination and a posterior median parietal projection. It is part of the cranium and disarticulated mandibular elements of further distinguished from the co-occurring Procolophon trigo- BP/1/1187 from the largest part of the block. This fracture was niceps by a number of characters (see below), including a longer filled with non-reversible glue, probably in the field or during snout and the absence of quadratojugal horns. preparation for Gow’s (1977) study, making it difficult to search for additional remains of the left side of the cranium. Removal of 2.1. Description the glue could cause serious damage to the prepared and already informative parts of the specimen, and for this reason, no attempt 2.1.1. Cranium of further preparation was done below the exposed regions of The cranium of BP/1/1187 (Figs. 2 and 3A) is compressed the . Instead, some additional preparation was carried out laterally and fractured loosely along the midline, producing the on the exposed side of the specimen. separation of right and left sides before burial of the specimen. Kitchingnathus possesses a gracile skull. The snout is elon- Most of the left side of the cranium is probably missing. Some gated, and slightly deeper than in Coletta seca but comparable unidentified flat bones that lay below the posterior margin of to that of Tichvinskia vjatkensis from Russia (see Ivakhnenko, the right side of the cranium presumably belong to the left side. 1973). The external surface of the snout is not well preserved, A tooth bearing fragment may represent a portion of the left and it is very difficult to trace the sutures of the premaxilla, the maxilla exposed in medial view (Fig. 2B, ?lmx). A fracture sep- nasal, the maxilla and the frontal in this area. A fracture has arates the thin layer of matrix that contains most of the visible separated most of the right premaxilla and a small portion of the

Fig. 2. (A) Kitchingnathus untabeni n. gen. et n. sp., Lower Triassic, South Africa, BP/1/1187, holotype. Photograph of the skeleton. (B) Outline of the skeleton. Abbreviations: ac, anterior coracoid; ap, autopodium; c, clavicle; cr, cranium; g, gastralia; i, interclavicle; il, ilium; f, femur; lm, left mandibular ramus; lmx, left maxilla; of, orbitotemporal fenestra; r, rib; rm, right mandibular ramus; sc, sacrum; vt, vertebra. Digits are identified with Roman numerals ii–v. Postcranial bones that could not be identified are not labelled. J.C. Cisneros / Palaeoworld 17 (2008) 126–134 129

Fig. 3. Kitchingnathus untabeni n. gen. et n. sp., Lower Triassic, South Africa, BP/1/1187, holotype. (A) Cranium, right view. (B) Right mandible in lateral view and selected teeth in occlusal view. (C) Left mandible in medial view and selected teeth in occlusal view. (D) Right mandible, lateral view. (E) Left mandible, dorsolateral view. (F) Left mandible, posterodorsal view. Abbreviations: amf, anterior maxillary foramen; d, dentary; cr, coronoid; f, frontal; j, jugal; l, lacrimal; mx, maxilla; n, nasal; op, opisthotic; p, parietal; pf, pineal foramen; pmx, premaxilla; pof, postfrontal; prf, prefrontal; pt, pterygoid; q, quadrate; qj, quadratojugal; sp, splenial; st, supratemporal; ect, ectopterygoid. Unshaded surfaces represent features preserved as natural casts. Roman numerals indicate tooth positions. Small-scale bar represents 5 mm for parts A, B and C, except for teeth in occlusal view where it represents 2 mm. Large-scale bar represents 5 mm for parts D, E and F. maxilla from the rest of the skull. The external naris is subcircu- (Modesto et al., 2002). Owenettids, however, have consider- lar. The anterior maxillary depression is damaged, and is located ably higher upper tooth counts (e.g., more than 30 in Owenetta on the anterior portion of the maxilla, adjacent to the posterior rubidgei, Reisz and Scott, 2002). The upper marginal teeth are margin of the external naris. This depression presumably com- not inset from the maxillary surface, a feature that is common prises a small part of the nasal but it is not possible to locate to basal procolophonids such as Coletta, Pintosaurus, Phaan- the suture between the maxilla and the nasal with confidence to thosaurus and Sauropareion (Ivakhnenko, 1979; Modesto et al., confirm this. No septomaxilla is preserved. 2001, 2002; Pineiro˜ et al., 2004). The premaxilla–maxilla suture Sixteen upper right marginal teeth are present. This is an ele- is not preserved but, as in most procolophonids, it is probably vated marginal tooth count for a procolophonid. Only Coletta located below the anterior maxillary depression. A small tooth seca from South Africa is known to have a comparable upper (Fig. 3A(iv), probably a replacement tooth) is located at this tooth count, 15 and 16, on the left and right side respectively position, and it could represent the fourth premaxillary tooth 130 J.C. Cisneros / Palaeoworld 17 (2008) 126–134 or the first maxillary one. Therefore, a maximum of four pre- many procolophonids. The large supratemporal closely resem- maxillary teeth is likely. Three premaxillary teeth are present in bles that of Sauropareion, as depicted by Modesto et al. (2001). It almost all procolophonids and four in Coletta seca (Modesto et is essentially rectangular, its anteroposterior length being larger al., 2002). All premaxillary teeth and the first few maxillary teeth than its mesolateral length. The supratemporal possesses a flat are conical. The conical tooth region comprises seven teeth, and occipital surface (best shown in Fig. 2A) that is equivalent to extends to the level of the anterior maxillary foramen. The first approximately half of the dorsal surface. There is no evidence three are enlarged (ca. 50 per cent longer than other upper teeth) for postparietals. and their apices are slightly recurved. All the conical teeth of Kitchingnathus are thicker than the teeth of owenettids, but less 2.1.2. Mandible bulbous than the conical teeth of Procolophon. The crown of the The right mandibular ramus (Fig. 3B and D) is exposed in seventh tooth is preserved partially as a natural mould. There is a lateral view. The anterior and posterior portions of this ramus are space between the seventh tooth and the eighth tooth. Although missing, and its ventral surface is damaged. Posteriorly, a long this space is large enough to hold another tooth, no socket or element that lays partially below this ramus likely represents pulp cavity is present. The molariform region comprises nine the dislocated quadrate process of the right pterygoid. Most of teeth. The crowns of the eighth and the sixteenth teeth, the latter the dentary is present but its sutures with other elements in the being the last maxillary tooth, are fully exposed. These teeth are mandible are poorly preserved. Parts of the splenial are visi- molariform with labiolingually expanded bases, the maximum ble through the damaged ventral portion of the mandible. Most width of which occurs at the base. The crowns are bicuspid. The of this bone was presumably covered in life by the dentary in labial cusp is higher than the lingual cusp, and the cusps are lateral view. The articular is not preserved, but the position of connected by a labiolingual ridge. the quadrate indicates that it was located at the alveolar level The rim of the orbitotemporal fenestrae is formed by the of the dentary teeth, not below it as in leptopleuronine procolo- lachrymal, the prefrontal, the parietal, the postfrontal, the jugal, phonids (Sues et al., 2000; Cisneros and Schultz, 2003, Fig. 2g). and presumably the postorbital. Only portions of the lachrymal Thirteen teeth are preserved in the right dentary; the anterior- and the prefrontal can be traced. As in other procolophonids, a most incisiforms are missing (Fig. 3B and D). These teeth are small lateral extension of the frontal reaches the orbitotemporal not inset from the dentary surface. The first preserved tooth in fenestra, precluding the prefrontal and postfrontal from con- the dentary is well exposed. It is monocuspid and conical, sub- tacting each other in dorsal view. The postfrontal is not fused circular in basal cross-section, and its maximum width occurs to the parietal, contrary to the condition present in Tichvinskia at the cervix. The two following teeth are partially covered by (Ivakhnenko, 1973), Kapes (Novikov and Sues, 2004), Hypsog- matrix, but they are likely conical. Only one cusp is visible on nathus (Sues et al., 2000) and other genera. The postfrontal is each of them, positioned roughly at the centre of the crown. The long and narrow, decreasing in width towards its anterior edge. fourth preserved tooth is labiolingually expanded and the only The subtemporal emargination is broad, in contrast with the cusp preserved is positioned labially. The two following teeth are genus Sauropareion, in which the emargination is acute and nar- smaller in height and are probably replacement elements. Their row as in owenettids (Modesto et al., 2001). The subtemporal crowns, and those of the following teeth, were prepared. These emargination is formed by the maxilla, the jugal and the quadra- are molariform, and, as in the upper teeth, the labial cusps are tojugal. The posterior process of the maxilla is unusually long higher and sharper than the lingual cusps and are connected by and thin, and contributes as much as the quadratojugal to the bor- a labiolingual ridge. This ridge is sigmoidal in occlusal view but der of the subtemporal emargination. In other procolophonids, its sinuosity is less pronounced than in the lower molariforms of the posterior process of the maxilla is shorter and contributes less Procolophon (Carroll and Lindsay, 1985, Fig. 14). The crowns than the quadratojugal, or is completely excluded from the rim of the following teeth could not be prepared. Fifteen teeth were of the subtemporal emargination. A portion of the transverse probably present in the right mandible and a maximum of 10 flange of the pterygoid or ectopterygoid can be seen through bicuspid molariforms is likely. the subtemporal emargination, but it is not possible to identify The left ramus (Fig. 3C, E and F) is exposed in medial view. the suture between these elements. The quadratojugal appears It is heavily weathered and only part of the dentary is present. to be higher than wide, although its complete width cannot The teeth are fractured at the base and their pulp cavities are be assessed because the otic notch lays covered with matrix. exposed. It is not clear if the teeth possess real roots, but pulp The quadratojugal lacks the lateral spine characteristic of other cavities below the tooth cervices are shallow. Most crowns are procolophonids. Part of the quadrate is visible below the quadra- well preserved. The dentition of this ramus shows 15 teeth. The tojugal; it is placed slightly below at the alveolar level of the three mesialmost teeth are preserved mainly as natural moulds maxilla. The squamosal and the postorbital are covered by the and are conical, presumably monocuspid. These are followed dislocated supratemporal. by four more conical, monocuspid teeth. The last molariform is The right half of the pineal foramen is present. It is essentially preserved as a mould. At least eight bicuspid molariforms are circular as in most procolophonids and it appears to be placed present (Fig. 3C, E and F). in a shallow fossa. The parietal is broad and has a long contact with the supratemporal. The fronto-parietal suture is not visible. 2.1.3. Postcranium A smooth process extends from the posterior margin of the pari- The partial postcranium (Fig. 2) is exposed in dorsal view, etal which forms half of the median parietal projection present in but is poorly preserved. The vertebral column was not preserved J.C. Cisneros / Palaeoworld 17 (2008) 126–134 131 except for the sacrals, adjacent vertebrae, and a few isolated explained by an early developmental stage within Procolophon, vertebrae. Some thoracic and sacral ribs are present, as well as including: (1) marginal upper and lower dentitions that are not gastralia. None of the thoracic ribs are preserved in full length, inset from the surfaces of the maxilla and the dentary, respec- so it is not possible to see if the thoracic rib cage is expanded as tively; (2) an elongated, low snout (pre-orbital length, character in derived procolophonids. Part of the pectoral girdle is present 4inCisneros, 2008b); (3) a long posterior maxillary process; mainly as a mould. This includes the interclavicle, a portion (4) a large supratemporal that is subrectangular in dorsal view; of the left clavicle, and paired coracoids. The right coracoids and (5) a slender quadratojugal. These anatomical features are are better preserved than the left ones. Both anterior and poste- in contrast not only with adult Procolophon individuals but with rior coracoids are essentially rounded. Coracoids are not known juveniles as well. Some Karoo specimens (Fig. 4; see also Carroll in most procolophonids, but in Procolophon (BP/1/962) and in and Lindsay, 1985, Fig. 7) are much smaller than those consid- SAM PK-K7711, a specimen from the Middle Triassic subzone ered by Gow (1977) and provide examples of individuals that BoftheCynognathus AZ erroneously referred to Procolophon can be readily referred to Procolophon trigoniceps but are mor- by deBraga (2003, Figs. 3 and 5; see Cisneros, 2008a), the phologically incompatible with BP/1/1187. These specimens posterior coracoid is anteroposteriorly elongated. feature a reduced number (six or less) of very enlarged molari- The only visible portion of the pelvic girdle lies adjacent to forms that are inset from the maxillary wall, plus a robust, deep the pectoral girdle. This may be the result of the specimen being snout, a short posterior maxillary process, a reduced supratem- in a curled-up position before dying and/or postmortem disartic- poral that is triangular in dorsal view and a robust quadratojugal ulation. At least two sacral vertebrae can be distinguished based with a small lateral process. It is very unlikely, judging from on the presence of sacral ribs. Both ribs are preserved on the first their enlarged molariforms, that any of these young Procolophon sacral vertebrae and a right rib lies on the second sacral vertebrae. individuals could have fed on insects according to the model The distal portions of these ribs are expanded and overlapping. A proposed by Gow (1977). count of three sacral vertebrae, however, is likely. Three sacrals It must be mentioned that when BP/1/1187 was first con- are normal for procolophonids and owenettids (see Ivakhnenko, sidered by Gow (1977) no other procolophonoids were known 1979; Reisz and Scott, 2002; deBraga, 2003). Sacral ribs may in the Lystrosaurus AZ besides Procolophon. Four more pro- have become detached from the third sacral vertebra. The right colophonoids, however, are now recognized in this biozone: ilium is partially preserved. It is articulated to two sacral ribs and Coletta seca (Gow, 2000), ‘Owenetta’ kitchingorum (Reisz and extends posteriorly parallel to the third putative sacral vertebra. Scott, 2002), Sauropareion anoplus (Modesto et al., 2001), and The right femur is preserved in articulation with the ilium. A Saurodektes rogersorum (Modesto et al., 2003). These new pro- autopodium is preserved between the right femur and the cra- colophonoids are smaller and more gracile than Procolophon nium, but it is not possible to confirm if it belongs to the forelimb trigoniceps. In the description of Coletta seca, Gow (2000, p. or the hindlimb. Four digits have been tentatively identified in 22) conceded that BP/1/1187 could represent a new taxon. this autopodium. 3.2. Phylogenetic relationships of the new taxon 3. Discussion In to evaluate the phylogenetic position of Kitch- 3.1. Comparison with Procolophon juveniles ingnathus untabeni, a cladistic analysis of procolophonid relationships was performed. The new taxon was added to the BP/1/1187 was originally referred to Procolophon trigoni- matrix of 23 taxa and 58 characters for procolophonids com- ceps by Gow (1977), although he openly admitted that this piled by Cisneros (2008b). The analysis was performed with specimen fell outside the range of variation of the species (Gow, TNT (Goloboff et al., 2003) following the same settings used by 1977, p. 701). The basis for his claim was that BP/1/1187 would Cisneros (2008b), using the Implicit Enumeration algorithm and represent an early ontogenetic stage, earlier than all other spec- Collapsing Rule 1 (minimum length = 0), with some “ordered” imens of Procolophon trigoniceps he examined. Gow (1977) characters (0, 7, 17, 25, 30, 31) and equal weights. A prelim- suggested that very young Procolophon individuals could have inary run produced 14 most parsimonious trees (MPTs, tree a more numerous marginal dentition, specialized for insectivory, length = 118, CI = 0.661 [excluding uninformative characters], that was completely replaced between the ontogenetic stages RC = 0.527), placing Kitchingnathus untabeni in a polytomy represented by BP/1/1187 and BP/1/959 (a small Procolophon with the basal forms Coletta, Sauropareion, Pintosaurus and specimen equivalent in size to BP/1/1187). There is no com- Phaanthosaurus; and a clade that includes all other procolo- pelling evidence to allow determination of the ontogenetic stage phonids considered in the analysis (clade C sensu Cisneros, of BP/1/1187 at the time of death. Nevertheless, the skeletal ele- 2008b). The analysis was run again with the same settings but ments of BP/1/1187 appear to be well ossified, and the specimen excluding Pintosaurus, a taxon which could only be coded for is compatible in size with adults of other Early Triassic procolo- 18 out of 58 characters. This analysis produced a single MPT phonids, e.g. the Russian form Tichvinskia vjatkensis which is (Fig. 5) and identifies Kitchingnathus untabeni as a basal form, known from a series of individuals (Ivakhnenko, 1979). being the sister taxon of a group formed by Phaanthosaurus As noted in the description, BP/1/1187 differs from Pro- and clade C (Cisneros, 2008b). Two non-ambiguous synapo- colophon trigoniceps not only in the number and morphology of morphies support the placement of Kitchingnathus in this group: its marginal teeth, but in several characters that could hardly be a broadly excavated ventral margin of the temporal region of 132 J.C. Cisneros / Palaeoworld 17 (2008) 126–134

Fig. 4. Crania of juvenile Procolophon trigoniceps individuals from the South African Karoo. Parts (A and B) dorsal view and parts (E and F) left lateral view of AMNH 4980 (locality unknown); parts (C and D) left lateral view and parts (G and H) dorsal view of NM QR1447, from Bethulie, Free State Province. Abbreviations: a, angular; amf, anterior maxillary foramen; ar, articular; cr, coronoid; d, dentary; f, frontal; j, jugal; l, lacrimal; mx, maxilla; mc, meckelian canal; n, nasal; p, parietal; pf, pineal foramen; pmx, premaxilla; po, postorbital; pof, postfrontal; prf, prefrontal; q, quadrate; qf, quadrate foramen; qj, quadratojugal; sa, surangular; sm, septomaxilla; sq, squamosal; st, supratemporal. the skull (character 12:2) and the loss of a distinct postparietal Hotton et al., 1997; Reisz and Sues, 2000). The feeding habits (character 16:1). This analysis produced a sister taxon relation- of Kitchingnathus were probably different from those of derived ship between the South African forms Coletta and Sauropareion, procolophonids, such as Procolophon or , which and the two taxa share the absence of teeth or denticles along are traditionally considered to be durophagous/herbivorous the posterior medial suture of the vomer (character 35:1). This (Colbert, 1946; Gow, 1977; Reisz and Sues, 2000). Unlike dichotomy has not been reported by previous workers on pro- Procolophon, the cusps in the molariforms of the new taxon colophonid relationships that evaluated both taxa, and could be are sharp and the crowns are not notably worn, a condition a result of the presence of a new basal procolophonid in the that is not compatible with the practice of durophagy or high- analysis. fibre herbivory (Hotton et al., 1997). The presence of numerous Character optimisation (Fig. 5) suggests that bicuspid conical teeth and small molariforms with sharp cusps instead marginal dentition arose twice within Procolophonoidea, the suggests an insectivorous niche (Gow, 1977). The dentition only parareptile lineage that developed this tooth morphol- of Kitchingnathus indeed resembles that of modern hedge- ogy. The analysis indicates that the bicuspid tooth condition hogs, which use their teeth to tear and puncture a variety of was acquired by Kitchingathus and again later in a clade that invertebrates. comprises the genus Tichvinskia together with the groups Pro- With the discovery of Kitchingnathus untabeni, there are colophoninae and Leptopleuroninae sensu Modesto et al. (2002). now five procolophonoids known from the Katberg Formation Most procolophonids are included in this clade. This hypothe- of the Beaufort Group (Fig. 1B). The new taxon co-occurs at sis, however, should be considered with caution due to the low the type locality, Hobbs Hill, with the well-known and abundant levels of support recorded in the analysis. form Procolophon trigoniceps. The three other procolophonoids reported for this formation, however, probably do not overlap 3.3. Palaeoecological and biostratigraphical the stratigraphic level of the new genus. These are the recently considerations described Coletta seca (Gow, 2000), Sauropareion anoplus (Modesto et al., 2001) and Owenetta kitchingorum (Reisz and Bicuspid and labiolingually expanded teeth constitute a major Scott, 2002). The only specimen of Coletta seems to come from acquisition that allowed the exploitation of durophagous and/or the lower or middle part of the Katberg Formation (Botha et high-fibre herbivorous niches by (Colbert, 1946; al., 2007). Owenetta kitchingorum and Sauropareion anoplus J.C. Cisneros / Palaeoworld 17 (2008) 126–134 133

Fig. 5. Most parsimonious hypothesis of procolophonid relationships produced by TNT. Tree length = 115, CI = 0.678 (excluding uninformative characters); RC = 0.545. Symmetric resampling and decay index values are provided before each node (above and below, respectively) as measurements of support. Sym- metric resampling was calculated from 5000 replicates (p = 33). The presence of bicuspid marginal teeth is indicated by asterisks. Sauropareion anoplus was recoded as polymorphic for character 49 (ectepicondylar foramen or groove on humerus present [0] or absent [1]) based on personal observation on specimen NM QR3544 (see also Botha et al., 2007, Fig. 1). Kitchingnathus untabeni was coded [12]1??0 10?00 [02]020? 110?? ???00 [12]0100 1200? ????1 0???? ????? ????? ??0. were first reported for the underlying Palingkloof Member of author was recipient of a grant from the Palaeontological Sci- the (Damiani et al., 2003) but there are now entific Trust (PAST) in South Africa and Conselho Nacional de records in the Katberg Formation below the stratigraphical range Desenvolvimento Científico e Tecnológico (CNPq) in Brazil. of Procolophon (Abdala et al., 2006; Botha et al., 2007). References

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