First occurrence of the dicynodont Digalodon (Therapsida, Anomodontia) from the Lopingian upper Madumabisa Mudstone Formation, Luangwa Basin, Zambia Kenneth D. Angielczyk1,2 1Integrative Research Center, Field Museum of Natural History, 1400 South Lake Shore Drive, Chicago, Illinois 60605, U.S.A. 2Evolutionary Studies Institute, University of the Witwatersrand, Private Bag 3, WITS, Johannesburg, 2050 South Africa Received 24 January 2019. Accepted 23 April 2019 INTRODUCTION Digalodon rubidgei Broom and Robinson, 1948 numbers among the last dicynodonts named by Robert Broom (Wyllie 2003). As with much of Broom’s taxonomic work, the description of D. rubidgei consists of only a few short paragraphs of text and two line drawings of the holotype, and it was nearly four decades before D. rubidgei began to be re-assessed. Cluver & King (1983) made a cursory com- parison between D. rubidgei and Aulacephalodon, and King (1988) carried this further by tentatively suggesting that Digalodon was a junior synonym of Aulacephalodon, echoing Broom and Robinson’s suggestion that Digalodon and Aulacephalodon were ‘allied’ (1948: 404). In contrast, Brink (1986) considered Digalodon a synonym of Dicyno- dontoides, but he did not discuss the rationale behind this conclusion. Angielczyk et al. (2009) disagreed with both of these hypotheses in their taxonomic revision of Dicyno- dontoides, instead suggesting that D. rubidgei was likely a valid taxon. Kammerer et al. (2015a) undertook the first detailed examination of Digalodon since Broom and Robinson named the taxon. They redescribed the holotype, con- firmed the validity of D. rubidgei, identified additional specimens, discussed the possibility of sexual dimor- phism, and investigated its phylogenetic relationships, concluding that Digalodon is a member of Emydopoidea. Perhaps most importantly, Kammerer et al. (2015a) noted that all of the specimens of D. rubidgei known at that time were collected from strata thought to be close to the boundary between the Cistecephalus and Daptocephalus assemblage zones (also see Viglietti et al. 2016) at localities in the vicinity of Graaff-Reinet in the Karoo Basin. Several other therapsids have their only Karoo records in this restricted geographic and stratigraphic interval (Kammerer et al. 2015a,b; Kammerer 2016, 2017; Van den Brandt & Abdala 2018), although the underlying causes for this pattern are uncertain (Kammerer 2017). Dicynodont fossils were first discovered in the Permian rocks of the Luangwa Basin of Zambia in 1925 (Dixey 1937), with the first substantive report of Zambian specimens being provided by Boonstra (1938). Additional fieldwork in the basin was carried out in the early 1960s and early 1970s, with a brief reconnaissance in 2000 (see reviews in Angielczyk et al. 2014; Sidor & Nesbitt 2018). Most recently, field crews led by the University of Washington and the Field Museum of Natural History have collected fossils in the Luangwa Basin in 2009, 2011, 2014, and 2018 [2012 Zambian fieldwork mentioned by Sidor & Nesbitt (2018) only occurred in the Mid-Zambezi Basin]. Lopingian fossils occur in the upper Madumabisa Mudstone Forma- tion in the Luangwa Basin (e.g. Drysdall & Kitching 1963), ISSN 2410-4418 Palaeont. afr. (2019) 53: 219–225 219 Palaeontologia africana 53: 219–225 — ISSN 2410-4418 [Palaeontol. afr.] Online only Permanently archived on the 26th of April 2019 at the University of the Witwatersrand, Johannesburg, South Africa This article is permanently archived at: http://wiredspace.wits.ac.za/handle/10539/26832 *Author for correspondence. E-mail: kangielczyk@fieldmuseum.org Digalodon is a rare emydopoid dicynodont first described from upper Permian rocks in the Karoo Basin of South Africa. During field- work in the upper Madumabisa Mudstone Formation of the Luangwa Basin (Zambia) in 2014, a small dicynodont skull was discovered that conforms very well to the recently revised diagnosis of Digalodon rubidgei, although some minor differences between the Zambian and South African specimens are apparent. The Zambian occurrence of Digalodon expands the known geographic range of the genus, which was previously limited to a small set of localities in the vicinity of the town of Graaff-Reinet (Eastern Cape). Based on historical specimens, Digalodon is thought to have a comparatively short stratigraphic range in the Balfour Formation that spans the boundary between the Cistecephalus and Daptocephalus assemblage zones. This observation may allow refinement of biostratigraphic correlations between the Karoo and Luangwa Basins, but discovery of more precisely-provenanced specimens in the Karoo is needed to fully assess Digalodon’s biostratigraphic utility. Keywords: Synapsida, Dicynodontia, Emydopoidea, Permian, biostratigraphy, biogeography. Palaeontologia africana 2019. ©2019 Kenneth D. Angielczyk. This is an open-access article published under the Creative Commons Attribution 4.0 Unported License (CC BY4.0). To view a copy of the license, please visit http://creativecommons.org/licenses/by/4.0/. This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. This article is permanently archived at: http://wiredspace.wits.ac.za/handle/10539/26832 http://creativecommons.org/licenses/by/4.0/ http://wiredspace.wits.ac.za/handle/10539/26832 mailto:kangielczyk@fieldmuseum.org http://wiredspace.wits.ac.za/handle/10539/26832 and various authors biostratigraphically correlated parts or all of this assemblage with equivalents of the modern Tropidostoma, Cistecephalus, and Daptocephalus assemblage zones of the Karoo (see review in Angielczyk et al. 2014). Based on their comprehensive study of the dicynodont component of the Madumabisa faunal assemblage, Angielczyk et al. (2014) proposed a correlation with the Cistecephalus Assemblage Zone, and Angielczyk & Kammerer (2017) suggested that a further refinement to upper Cistecephalus to lower Daptocephalus Assemblage Zone might be warranted. Although some of the taxa in the Madumabisa assemblage are endemic or have affini- ties with other biogeographic provinces (Angielczyk et al. 2014; Huttenlocker et al. 2015; Huttenlocker & Sidor 2016), the assemblage as a whole displays a strong degree of similarity to that of the Karoo Basin (Fröbisch 2009; Sidor et al. 2013; Bernardi et al. 2017). In the course of fieldwork in 2014, Sterling Nesbitt dis- covered a small dicynodont skull in upper Madumabisa Mudstone Formation strata exposed in North Luangwa National Park. Preparation of this specimen has revealed that it represents Digalodon, the first occurrence of this ge- nus outside of the Karoo Basin. Here, I detail the justifica- tion for this identification and discuss the specimen’s biostratigraphic and biogeographic implications. SYSTEMATIC PALAEONTOLOGY THERAPSIDA Broom, 1905 ANOMODONTIA Owen, 1860 DICYNODONTIA Owen, 1860 THEROCHELONIA Seeley, 1894 EMYDOPOIDEA van Hoepen, 1934 Digalodon cf. Digalodon rubidgei Broom and Robinson, 1948 Referred material. NHCC LB830, a nearly complete but somewhat dorsoventrally flattened skull (Fig. 1), parts of four vertebrae, and an elongate bone fragment that may be a partial clavicle. Although the postcranial elements were found in association with the skull, it is unclear whether they represent the same individual or even the same species because they were collected loose on the surface and were not in direct contact with the skull. Locality and Horizon. NHCC LB830 was collected near the southern border of North Luangwa National Park (North- ern Province, Zambia) along the banks of a seasonal tributary of the Mulondoshi River (a tributary of the Luangwa River). This locality (L322) also produced a skull of a new burnetiamorph that is currently under study (C.A. Sidor, pers. comm.; also see Sidor et al. 2015), and is about 175 m north of the locality of NHCC LB116 (L94), a specimen of Compsodon helmoedi described by Angielczyk & Kammerer (2017). Detailed locality information is avail- able to qualified researchers only from the author or NHCC because of past fossil poaching in the area (Sidor 2015). This locality falls in the Mid-Luangwa Basin of Barbolini et al. (2016) and exposes strata of the upper Madumabisa Mudstone Formation. The faunal assem- blage preserved in these strata correlates with the Cistecephalus and/or lower Daptocephalus assemblage zones of the Karoo Basin (Angielczyk et al. 2014; Angielczyk & Kammerer 2017). IDENTIFICATION Kammerer et al. (2015a) included the following charac- ters in their revised diagnosis of D. rubidgei: 1) small size (basal skull length <10 cm); 2) precaniniform embayment present; 3) paired anterior palatal ridges present; 4) long, horizontal beak that is sharply demarcated from the caniniform process; 5) tall zygomatic ramus of the squamosal with a folded over dorsal margin; 6) raised parietal ‘lips’ along the lateral edges of the pineal fora- men; 7) short frontal contribution to the orbital margin; 8) broad posterolateral expansion of the parietal that excludes the postorbital from the back of the skull roof. NHCC LB830 conforms very well to this diagnosis. The basal skull length of the specimen is 77.9 mm. The anterior tip of the snout is slightly damaged but the remains of the anterior median palatal ridges are clearly present (Fig. 2a), although they are roughly parallel for their entire length instead of bowing laterally at their posterior ends as in the holotype (RC 76) (Kammerer et al. 2015a). Lateral anterior palatal ridges also are present, helping to confirm a character state that was somewhat uncertain in the type but was visible in one of the referred specimens (B 42). The precaniniform embayment is visible on both sides of the skull (Fig. 2a). The original edge of the palatal rim is eroded, but the long, horizontal beak formed by the premaxilla and maxilla is obvious (Fig. 1c). Similar to the holotype, this portion of the palatal rim meets the anterior edge of the caniniform process at close to a ninety-degree angle (Fig. 1c), and an enlarged vascular foramen is present on the posterior surface of the caniniform process (Fig. 2e). A postcaniniform keel is present in NHCC LB830, but its ventral edge is more broadly rounded than the comparatively narrow keel present in the type. The bone surface in this area is somewhat cracked and damaged on both sides of the skull, however, so the difference may be an artefact of preservation. NHCC LB830 is unique among known specimens of Digalodon in its possession of complete caniniform tusks. The tusks are conical and taper to a fine point. There is no evidence of wear facets near the tips of the tusks, but the bases of the tusks bear low longitudinal ridges and shallow grooves near the margins of the alveoli. This orna- mentation appears to be related to the growth of the tusks, not a result of wear. The visible (erupted) portions of the tusk are not infolded to the degree seen in the pathologi- cal specimens described by Whitney et al. (2019), but it is important to note that the degree of infolding they observed was highest within the alveolus and decreased towards the tip of the tusk. This raises the possibility that the tusk roots of NHCC LB830 also may be infolded to a greater degree than is visible on the external surfaces of the specimen. Unlike the holotype, where the tusks are angled anteriorly, the tusks of NHCC LB830 are very straight and near-vertically oriented (Fig. 1c). The tusks are also broken off at the alveolar margin in B 42, but they seem to be more vertically oriented, so the anterior 220 ISSN 2410-4418 Palaeont. afr. (2019) 53: 219–225 angulation of the tusks in the holotype may be a result of deformation. The lateral edge of the zygomatic ramus of the squamosal is damaged on both sides of NHCC LB830 (Figs. 1a–b), making it impossible to assess whether the dorsal margin was folded over. However, enough of the right squamosal is preserved to indicate that the zygomatic ramus was relatively broad. It is more horizon- tal than in the type, but this may in part reflect the dorsoventral compression that NHCC LB830 has under- gone (also evidenced by the anterior curling of the ventral edge of the occipital plate and the breakage and lateral displacement of the ascending ramus of the epipterygoid on both sides of the skull). The cortical surface of the skull roof is eroded and highly cracked, obscuring many sutural details. Because of this damage, the size of the frontal contribution to the orbital margin is uncertain. However, part of the frontal– postorbital suture is preserved on the left side of the skull, and it indicates that the postorbital had an anterior pro- cess that extended beyond the level of the postorbital bar (Fig. 2b). This resembles the morphology present on the right side of the holotype, and is consistent with a relatively small frontal contribution to the orbit. The pineal foramen is circular and surrounded by a raised eminence. The dorsal edge of the eminence is broken, and this breakage reveals that the walls of the eminence were widest laterally and narrowed both anteriorly and posteriorly (Fig. 2c). This resembles the condition in the type, although as preserved the eminence of NHCC LB830 forms more of a complete raised rim around the pineal foramen instead of lateral thickenings separated by distinct anterior and posterior grooves. Grooves may have been more apparent when the walls of the eminence reached their original height, but it is also possible the NHCC LB830 had a more dome-like pineal boss, comparable to that seen in Diictodon or Eosimops (Sullivan & Reisz 2005; Angielczyk & Rubidge 2013). As in the holotype, the posterior ramus of the postorbital is strongly bi-planar, with distinct dorsal and lateral sur- faces that are perpendicular to each other. The parietals are widely exposed on the dorsal surface of the inter- temporal bar, as in South African specimens of D. rubidgei, although the temporal bar itself is proportionally wider. ISSN 2410-4418 Palaeont. afr. (2019) 53: 219–225 221 Figure 1. Zambian specimen of Digalodon cf. D. rubidgei (NHCC LB830) in dorsal (A), ventral (B), right lateral (C), and posterior (D) views. The long, horizontal beak that is sharply demarcated from the caniniform process (1) is diagnostic of Digalodon. Scale bar is 2 cm. This can be easily visualized by the fact that the edges of the intertemporal bar are approximately aligned with the margins of the interorbital skull roof in most South African specimens (e.g. RC 498), whereas in NHCC LB830 the edges of the intertemporal bar extend farther laterally than the orbital margins. The posterior portion of the suture between the postorbital and the parietal is well preserved on the right side of the skull roof. There, it is clear that the parietal had a well-developed posterior process that excluded the postorbital from the posterior edge of the skull roof (Fig. 2c). Although they did not include them in their formal diag- nosis of D. rubidgei, Kammerer et al. (2015a) described two other unusual characters in the holotype that also are apparent in NHCC LB830. First, in contrast to most other emydopoids (Angielczyk 2001; Angielczyk & Kurkin 2003), the palatine pad of RC 76 is not pierced by a palatine foramen and this is also the case in NHCC LB830 (best preserved on the right side of the skull; Fig. 2a). Second, the exoccipitals of the holotype do not appear to have been fully fused with the other bones of the occiput, with an open suture between the exoccipital and the opisthotic being especially clear. Sutures delineating the margins of the exoccipital are not clear on the occiput of NHCC LB830. However, as noted above, the occiput of the speci- men has been deformed in response to dorsoventral compression. Some of the buckling associated with this deformation, especially on the right side of the skull, resulted in pieces of bone in the vicinity of the exoccipitals being displaced slightly posteriorly relative to the rest of the occiput, with raised areas of matrix filling the surrounding cracks (Fig. 1d). Although it is uncertain how precisely this breakage followed the sutures surrounding the exoccpitals, it does suggest an area of weakness existed in this part of the skull, as would be expected if the sutures were not fully co-ossified. In summary, NHCC LB830 displays almost all of the diagnostic features of D. rubidgei that were enumerated by Kammerer et al. (2015). Even in cases where damage prevents a definitive assessment of a character state (e.g. small frontal contribution to the orbital margin, down- turned edge of the zygomatic ramus of the squamosal), 222 ISSN 2410-4418 Palaeont. afr. (2019) 53: 219–225 Figure 2. Close-ups of the Zambian specimen of Digalodon cf. D. rubidgei (NHCC LB830) showing characters important for identification. A, secondary palate in ventral view showing precaniniform embayment (1), anterior median palatal ridges (2), and absence of a palatine foramen (3). B, left side of skull roof in dorsal view showing the anterior process of the postorbital that extends past the postorbital bar (4), suggestive of a small frontal contribu- tion to the orbit. C, right side of intertemporal region in dorsal view showing parietal lips around the pineal foramen that are widest laterally (5), and the broad posterloateral expansion of the parietal that excludes the postorbital from the back of the skull roof (6). D, Right side of occipital plate in posterior view showing matrix-filled cracks (7) in the vicinity of the exoccipital that may represent areas of weakness associated with unfused sutures. E, right maxilla in ventrolateral view showing the enlarged vascular foramen (8) on the posterior surface of the caniniform process. Scale bar is 5 mm. Abbreviations: eo, exoccipital; fm, foramen magnum; fr, frontal; op, opisthotic; or, orbit; pa, parietal; ptf, posttemporal fenestra; po, postorbital; so, supraoccipital. the preserved parts of the specimen are suggestive of the states expected for D. rubidgei originally being present. NHCC LB830 also possesses characters found in D. rubidgei that are otherwise rare among emydopoids (e.g. absence of a palatine foramen). However, several differ- ences also are apparent, including anterior median palatal ridges that do not diverge posteriorly, more vertical tusks, more rounded postcaniniform keel, more horizontal zygoma, more continuous raised rim of the pineal fora- men, and proportionally broader intertemporal bar. Based on these observations, I consider the identification of NHCC LB830 as a member of the genus Digalodon to be well justified, but its referral to the species D. rubidgei is less certain. The differences between NHCC LB830 and the South African specimens may represent intraspecific variation that would be more apparent if a larger sample of D. rubidgei was available, but it could also indicate a species-level divergence between Zambian and South African populations of Digalodon. The situation is further complicated by the dorsoventral flattening experienced by NHCC LB830, which may explain some differences (e.g. more horizontal zygoma in NHCC LB830) but not others (e.g. the wider intertemporal bar is unlikely an artefact of deformation because the interorbital skull roof also is proportionally narrower relative to basal skull length). A larger number of specimens from both the Karoo and Luangwa basins (and ideally other southern African basins) is needed to fully resolve these issues, and in light of this uncertainty I consider it most conservative to identify NHCC LB830 as Digalodon cf. D. rubidgei instead of formally referring it to the species D. rubidgei or erecting a new species. DISCUSSION The upper Madumabisa Mudstone Formation of the Luangwa Basin preserves an important late Permian tetrapod assemblage that has strong similarities to contemporary assemblages from the Karoo Basin (Fröbisch 2009; Sidor et al. 2013; Angielczyk et al. 2014; Bernardi et al. 2017). However, the Madumabisa assem- blage displays lower species richness than the Ciste- cephalus or Daptocephalus assemblage zones of the Karoo, and Roopnarine et al. (2018) hypothesized that this was likely the result of incomplete sampling of the Luangwa Basin fossil record. Digalodon clearly was a rare dicyno- dont, with fewer than ten specimens identified world- wide (Kammerer et al. 2015a). Its discovery in Zambia in the course of recent fieldwork corroborates Roopnarine et al.’s (2018) hypothesis that less abundant elements of the Madumabisa assemblage remain unrecognized, under- scoring the importance of continued collecting in this formation. The Zambian record of Digalodon expands the geo- graphic range of the genus. Prior to this, it was known only from a restricted set of Karoo localities in the vicinity of Graaff-Reinet (Kammerer et al. 2015a), and it now becomes another example of the surprisingly good dis- persal abilities of small dicynodonts (e.g. Angielczyk & Sullivan 2008; Angielczyk et al. 2014; Angielczyk & Kammerer 2017). Several other therapsid taxa seem to be largely limited in their occurrences to this area of the Karoo (Kammerer et al. 2015a,b; Kammerer 2016, 2017; Van den Brandt & Abdala 2018), and among these taxa Kitchinganomodon and Compsodon also are present in the Madumabisa assemblage (Angielczyk et al. 2014, Angielczyk & Kammerer 2017). It is not clear whether the geographically-restricted Karoo occurrences are an artefact of sampling or if they reflect a genuine pattern resulting from factors such as an unusual palaeo- environment or short time interval being represented at the localities (Kammerer 2017). Further collecting and research on the sedimentology, geochemistry, and geo- chronology of the Balfour Formation near Graaff-Reinet and the upper Madumabisa Mudstone Formation will be necessary to explain the reason for the biogeographic link between the Karoo sites and the Luangwa Basin. Never- theless, the presence of Digalodon in the Luangwa Basin is one more point of similarity between its Lopingian dicynodont fauna and that of the Karoo, and further differentiates it from the geographically proximal Ruhuhu Basin of Tanzania (also see discussion in Angielczyk et al. 2014). The currently-recognized stratigraphic range of Digalo- don in the Balfour Formation spans the upper Cistecephalus and lower Daptocephalus assemblage zones (Kammerer et al. 2015a; Viglietti et al. 2016). If this range is delineated correctly, it is additional evidence suggesting that the upper Madumabisa Formation assemblage is better corre- lated with this interval (also see Angielczyk & Kammerer 2017) instead of only the Cistecephalus Assemblage Zone, as suggested by Angielczyk et al. (2014). However, all but one (SAM-PK-K11551) of the Karoo specimens of Digalo- don are parts of historical collections whose geographic and stratigraphic provenance data lack modern levels of precision. SAM-PK-K11551 (Fig. 3 ) was collected in 2017 on the farm Riverdene (formerly Steilkrans), about 480 m below the Permo-Triassic boundary in the upper Oudeberg Member of the Balfour Formation. This farm is the type ISSN 2410-4418 Palaeont. afr. (2019) 53: 219–225 223 Figure 3. Dorsal view of a Digalodon rubidgei skull (SAM-PK-K11551) col- lected from a measured stratigraphic section in the Karoo Basin, South Africa, in 2017. This specimen establishes the presence of D. rubidgei in the Daptocephalus Assemblage Zone. locality of the Cistecephalus Assemblage Zone, which tradi- tionally included all of the Oudeberg Member (Smith & Keyser 1995). Recent research suggests that the upper- most Oudeberg Member actually hosts a lower Dapto- cephalus Assemblage Zone fauna, however (Viglietti et al. 2016, 2017). We use this correlation between the regional litho- and biostratigraphy, but it is important to note that this is an area of on-going active research (R. Smith, pers. comm.). Therefore, the stratigraphic position of SAM-PK- K11551 places the specimen near the base of the lower Daptocephalus Assemblage Zone, helping to confirm the previously hypothesized range of Digalodon in the Karoo. If additional specimens can be found in measured strati- graphic sections, it should be possible to more rigorously constrain its full stratigraphic range in that basin. Our on-going fieldwork in Zambia complements this process because it is generating an increasingly large database of geographically and stratigraphically well-provenanced specimens, particularly for North Luangwa National Park and the Munyamadzi Game Management Area of the Mid-Luangwa Basin. Work is now underway using this resource to test the hypothesis that a single faunal assem- blage is present in the upper Madumabisa Mudstone Formation in this region (B. Peecook, pers. comm.). Taken together, advances of this kind will provide the data needed to further refine biostratigraphic correlations between the Luangwa and Karoo basins. INSTITUTIONAL ABBREVIATIONS B Bremner Collection, Graaff-Reinet Museum, Graaff-Reinet, South Africa NHCC National Heritage Conservation Commission, Lusaka, Zambia RC Rubidge Collection, Graaff-Reinet, South Africa SAM Iziko Museums of South Africa, Cape Town, South Africa I thank J. Museba, K. Mwamulowe and C. Chipote (NHCC) for their assistance in obtaining research and export permits, and in carrying out fieldwork. N. Barbolini, C. Beightol, A. Goulding, J. Lungmus, J. McIntosh, J. Menke, S. Myers, S. Nesbitt, B. Peecook, C. Sidor, R. Smith, J.S. Steyer, N. Tabor, S. Tolan, R. Whatley and M. Whitney also made numerous contributions to fieldwork in Zambia and subse- quent research. Funding for fieldwork was provided by the National Geographic Society (CRE 8571-08 to J.S. Steyer; NGS-158R-18 to B. Peecook), the National Science Foundation (EAR-1337291 to K.D.A.; EAR-1337569 to C. Sidor), and The Field Museum IDP Foundation, Inc. African Training and African Partner Programs (to K.D.A.). E. Fitzgerald prepared NHCC LB830. R. Smith took the photograph of SAM-PK-K11551 in Figure 3, and R. Smith and P. Viglietti provided information about the stratigraphic position of the specimen. Helpful reviews by J. Fröbisch, C. Kammerer, and C. Olivier improved the manuscript. REFERENCES ANGIELCZYK, K.D. 2001. Preliminary phylogenetic analysis and strati- graphic congruence of the dicynodont anomodonts (Synapsida: Therapsida). Palaeontologia africana 37, 53–79. ANGIELCZYK, K.D. & KAMMERER, C.F. 2017. The cranial morphology, phylogenetic position, and biogeography of the Upper Permian dicynodont Compsodon helmoedi van Hoepen (Therapsida, Anomo- dontia). Papers in Palaeontology 3, 513–545. ANGIELCZYK, K.D. & KURKIN, A.A. 2003. Phylogenetic analysis of Russian Permian dicynodonts (Therapsida: Anomodontia): implica- tions for Permian biostratigraphy and Pangaean biogeography. Zoological Journal of the Linnean Society 139, 157–212. ANGIELCZYK, K.D. & RUBIDGE, B.S. 2013. Skeletal morphology, phylogenetic relationships and stratigraphic range of Eosimops newtoni Broom, 1921, a pylaecephalid dicynodont (Therapsida, Anomodontia) from the Middle Permian of South Africa. Journal of Systematic Palaeontology 11, 191–231. ANGIELCZYK, K.D. & SULLIVAN, C. 2008. Diictodon feliceps (Owen, 1876), a dicynodont (Therapsida, Anomodontia) species with a Pangaean distribution. Journal of Vertebrate Paleontology 28, 788–802. ANGIELCZYK, K.D., SIDOR, C.A., NESBITT, S.J., SMITH, R.M.H. & TSUJI, L.A. 2009. Taxonomic revision and new observations of the postcranial skeleton, biogeography, and biostratigraphy of the dicynodont genus Dicynodontoides, the senior subjective synonym of Kingoria (Therapsida, Anomodontia). Journal of Vertebrate Paleontology 29, 1174–1187. ANGIELCZYK, K.D., STEYER, J.S., SIDOR, C.A, SMITH, R.M.H., WHATLEY, R.L. & TOLAN, S. 2014. Permian and Triassic dicynodont (Therapsida: Anomodontia) faunas of the Luangwa Basin, Zambia: taxonomic update and implications for dicynodont biogeography and biostratigraphy. In: Kammerer, C.F., Angielczyk, K.D. & Fröbisch, J. (eds), Early Evolutionary History of the Synapsida, 93–138. Dordrecht, Springer. BARBOLINI, N., BAMFORD, M.K. & TOLAN, S. 2016. Permo-Triassic palynology and palaeobotany of Zambia: a review. Palaeontologia africana 50, 18–30. BERNARDI, M., PETTI, F.M., KUSTATSCHER, E., FRANZ, M., HARTKOPF-FRÖDER, C., LABANDEIRA, C.C., WAPPLER, T., VAN KONIJNENBERG-VAN CITTERT, J.H.A, PEECOOK, B.R. & ANGIEL- CZYK, K.D. 2017. Late Permian (Lopingian) terrestrial ecosystems: a global comparison with new data from the low-latitude Bletterbach Biota. Earth-Science Reviews 175, 18–43. BOONSTRA, L.D. 1938. A report on some Karroo reptiles from the Luangwa Valley, Northern Rhodesia. Quarterly Journal of the Geological Society of London 94, 371–384. BRINK, A.S. 1986. Illustrated bibliographic catalogue of the Synapsida. Geological Survey of South Africa Handbook 10. BROOM, R. 1905. On the use of the term Anomodontia. Albany Museum Records 1, 266–269. BROOM, R. & ROBINSON, J.T. 1948. Some new fossil reptiles from the Karroo Beds of South Africa. Proceedings of the Zoological Society of London 118, 392–407. CLUVER, M.A. & KING, G.M. 1983. A reassessment of the relationships of Permian Dicynodontia (Reptilia, Therapsida) and a new classifica- tion of dicynodonts. Annals of the South African Museum 91, 195–273. DIXEY, F. 1937. The geology of part of the upper Luangwa Valley, north-eastern Rhodesia. Quarterly Journal of the Geological Society of London 93, 52–74. DRYSDALL, A.R. & KITCHING, J.W. 1963. A re-examination of the Karroo succession and fossil localities of part of the upper Luangwa Valley. Geological Survey of Northern Rhodesia Memoir 1, 1–62. FRÖBISCH, J. 2009. Composition and similarity of global anomodont- bearing tetrapod faunas. Earth-Science Reviews 95, 119–157. HUTTENLOCKER, A.K. & SIDOR, C.A. 2016. The first karenitid (Therapsida, Therocephalia) from the Upper Permian of Gondwana and the biogeography of Permo-Triassic therocephalians. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2016.1111897 HUTTENLOCKER, A.K., SIDOR, C.A. & ANGIELCZYK, K.D. 2015. A new eutherocephalian (Therapsida, Therocephalia) from the Upper Permian Madumabisa Mudstone Formation of Zambia. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2015.969400 KAMMERER, C.F. 2016. Systematics of the Rubidgeinae (Therapsida: Gorgonopsia). PeerJ 4, e1608. KAMMERER, C.F. 2017. Rediscovery of the holotype of Clelandina major Broom, 1948 (Gorgonopsia: Rubidgeinae) with implications for the identity of this species. Palaeontologia africana 52, 85–88. KAMMERER, C.F., ANGIELCZYK, K.D. & FRÖBISCH, J. 2015a. Redescription of Digalodon rubidgei, an emydopoid dicynodont (Therapsida, Anomodontia) from the Late Permian of South Africa. Fossil Record 18, 43–55. KAMMERER, C.F., ANGIELCZYK, K.D. & FRÖBISCH, J. 2015b. Redescription of the geikiid Pelanomodon (Therapsida, Dicynodontia), with a reconsideration of ‘Propelanomodon’. Journal of Vertebrate Paleon- tology. DOI: 10.1080/02724634.2015.1030408 KING, G.M. 1988. Anomodontia, 17C. In: Wellnhofer, P. (ed.), Handbuch der Paläoherpetologie. Stuttgart, Gustav Fischer Verlag. OWEN, R. 1860. On the orders of fossil and Recent Reptilia, and their dis- tribution in time. Report of the 29th Meeting of the British Association for the Advancement of Science (1859), 153–166. SEELEY, H.G. 1894. Researches on the structure, organisation, and classi- fication of the fossil Reptilia. Part IX., Section 1. On the Therosuchia. Philosophical Transactions of the Royal Society of London, Series B, Biological Sciences 185, 987–1018. ROOPNARINE, P.D., ANGIELCZYK, K.D., OLROYD, S.L., NESBITT, S.J., BOTHA-BRINK, J., PEECOOK, B.R., DAY, M.O. & SMITH, R.M.H. 2018. Comparative ecological dynamics of Permian-Triassic communi- 224 ISSN 2410-4418 Palaeont. afr. (2019) 53: 219–225 https://doi.org/10.1080/02724634.2016.1111897 https://doi.org/10.1080/02724634.2015.1030408 https://doi.org/10.1080/02724634.2015.969400 ties from the Karoo, Luangwa, and Ruhuhu Basins of southern Africa. In: Sidor, C.A. & Nesbitt, S.J. (eds), Vertebrate and Climatic Evolution in the Triassic Rift Basins of Tanzania and Zambia. Society of Vertebrate Paleontology Memoir 17, 254–272. Journal of Vertebrate Paleontology 37 (6, supplement). SIDOR, C.A. 2015. The first biarmosuchian from the upper Madumabisa Mudstone formation (Luangwa Basin) of Zambia. Palaeontologia africana 49, 1–7. SIDOR, C.A. & NESBITT, S.J. 2018. Introduction to vertebrate and clima- tic evolution in the Triassic Rift Basins of Tanzania and Zambia. In: Sidor, C.A. & Nesbitt, S.J. (eds), Vertebrate and Climatic Evolution in the Triassic Rift Basins of Tanzania and Zambia. Society of Vertebrate Paleontology Memoir 17, 1–7. Journal of Vertebrate Paleontology 37 (6, sup- plement). SIDOR, C.A., KNAUB, C.R., ANGIELCZYK, K.D., BEIGHTOL, C.V., NESBITT, S.J., SMITH, R.M.H., STEYER, J.S., TABOR, N.J. & TOLAN, S. 2015. Tanzania and Zambia yield an unprecedented fossil record of burnetiamorph therapsids. Journal of Vertebrate Paleontology, Program and Abstracts, 2015, 213. SIDOR, C.A., VILHENA, D.A, ANGIELCZYK, K.D., HUTTENLOCKER, A.K., NESBITT, S.J., PEECOOK, B.R., STEYER, J.S., SMITH, R.M.H. & TSUJI, L.A. 2013. Provincialization of terrestrial faunas following the end-Permian mass extinction. Proceedings of the National Academy of Sciences 110, 8129–8133. SMITH, R.M.H. & KEYSER, A.W. 1995. Biostratigraphy of the Cistecephalus Assemblage Zone. In: Rubidge, B.S. (ed.), Biostratigraphy of the Beau- fort Group (Karoo Supergroup). South African Committee for Stratigra- phy Biostratigraphic Series 1, 23–28. SULLIVAN, C. & REISZ, R.R. 2005. Cranial anatomy and taxonomy of the late Permian dicynodont Diictodon. Annals of Carnegie Museum 74, 45–75. VAN DEN BRANDT, M.J. & ABDALA, F. 2018. Cranial morphology and phylogenetic analysis of Cynosaurus suppostus (Therapsida, Cynodon- tia) from the upper Permian of the Karoo Basin, South Africa. Palaeontologia africana 52, 201–221. VAN HOEPEN, E.C.N. 1934. Oor die indeling van die Dicynodontoidae na aanleiding van nuwe vorme. Paleontologiese Navorsing van die Nasio- nale Museum 2, 67–101. VIGLIETTI, P.A., SMITH, R.M.H., ANGIELCZYK, K.D., KAMMERER, C.F., FRÖBISCH, J. & RUBIDGE, B.S. 2016. The Daptocephalus Assem- blage Zone (Lopingian), South Africa: a proposed biostratigraphy based on a new compilation of stratigraphic ranges. Journal of African Earth Sciences 113, 153–164. VIGLIETTI, P.A., RUBIDGE, B.S., & SMITH, R.M.H. 2017. Revised lithostratigraphy of the Upper Permian Balfour and Teekloof forma- tions of the main Karoo Basin, South Africa. South African Journal of Geology 120, 45–60. WHITNEY, M.R., TSE, Y.T. & SIDOR, C.A. 2019. Histological evidence of trauma in tusks of southern African dicynodonts. Palaeontologia africana 53, 75–80. WYLLIE, A. 2003. A review of Robert Broom’s therapsid holotypes: have they survived the test of time? Palaeontologia africana 39, 1–19. ISSN 2410-4418 Palaeont. afr. 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