Postcranial osteology of the neotype specimen of Massospondylus carinatus Owen, 1854 (Dinosauria: Sauropodomorpha) from the upper Elliot formation of South Africa § Paul M. Barrett1,2* , Kimberley E.J. Chapelle2 , Casey K. Staunton2, Jennifer Botha3 & Jonah N. Choiniere2 1Department of Earth Sciences, Natural History Museum, Cromwell Road, London SW7 5BD, U.K. 2Evolutionary Studies Institute, University of the Witwatersrand, Private Bag 3, WITS 2050, Johannesburg, South Africa 3Department of Karoo Palaeontology, National Museum, PO Box 266, Bloemfontein 9300, South Africa Received 2 September 2018. Accepted 30 January 2019 Massospondylus carinatus Owen, 1854, from the earliest Jurassic upper Elliot Formation of South Africa, was one of the first dinosaurs to be described from Gondwana. It has been incorporated into numerous phylogenetic, palaeobiological and biostratigraphic analyses, is often viewed as an exemplar for understanding sauropodomorph anatomy and is a key taxon in studies of early dinosaur evolution. Since its initial description, numerous specimens have been referred to this species, ranging from isolated postcranial elements to complete skeletons with three-dimensional skulls. In addition, M. carinatus has been identified in areas outside of the main Karoo Basin. Surprisingly, however, there have been few attempts to define the taxon rigorously, so that the basis for many of these referrals is weak, undermining the utility of this abundant material. Here, we provide the first detailed postcranial description of the neotype specimen of M. carinatus, use it as a basis for diagnosing the species on the basis of cranial, axial and appendicular characters, demonstrate that it represents an adult individual on the basis of osteohistology, and discuss ways in which these data can assist in providing a better understanding of Karoo-aged African dinosaur faunas. Keywords: Massospondylus carinatus, Massospondylidae, Sauropodomorpha, upper Elliot Formation, postcranial anatomy, osteohistology, taxonomy. Palaeontologia africana 2019. ©2019 Paul M. Barrett, Kimberley E. J. Chapelle, Casey K. Staunton, Jennifer Botha & Jonah N. Choiniere. 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. The article and five supplements are permanently archived at: http://wiredspace.wits.ac.za/handle/10539/26829 INTRODUCTION et al. 2005). Indeed, Massospondylus specimens are so abun- Massospondylus carinatus Owen, 1854 was one of the first dant that it was designated the nominal taxon for the up- dinosaurs to be named from the southern hemisphere permost biostratigraphical range zone within the Karoo and since its initial description numerous complete skele- Supergroup of South Africa (Massospondylus Range Zone: tons, including skulls, and thousands of isolated elements Kitching & Raath 1984). It has also been used to infer corre- have been referred to this taxon (e.g. Cooper 1981; lations between Gondwanan basins, both regionally Kitching & Raath 1984; Gow et al. 1990). M. carinatus is a (Bond 1965; Cooper 1981) and internationally (Apaldetti non-sauropod sauropodomorph that is best known from et al. 2011). the latest Triassic/earliest Jurassic upper Elliot and Clarens As a result of these discoveries, M. carinatus is potentially formations (upper Stormberg Group) of the Karoo Basin one of the best-represented early dinosaurs and has in South Africa and Lesotho (e.g. Kitching & Raath 1984; formed the basis for numerous palaeobiological studies Gow et al. 1990; Sues et al. 2004; Knoll 2005; Chapelle & on locomotion (Bonnan & Senter 2007), growth rates Choiniere 2018), but additional material has also been (Chinsamy 1993; Erickson et al. 2001), tooth replacement reported from the Forest Sandstone and Mpandi forma- (D’Emic et al. 2013), ontogeny (Gow 1990; Gow et al. 1990; tions of the mid-Zambezi, Mana Pools and Tuli basins in Reisz et al. 2005, 2010) and nesting behaviour (Kitching Zimbabwe (e.g. Attridge 1963; Raath et al. 1970; Bond 1973; 1979; Zelenitsky & Modesto 2002; Reisz et al. 2012). It has Cooper 1981; Munyikwa 1997), which are thought to be also been an important exemplar in broader studies of correlative with upper Stormberg Group sediments (e.g. early dinosaur herbivory, palaeoecology and faunal Johnson et al. 1996; Bordy & Catuneanu 2001; Catuneanu studies (e.g. Raath 1974; Cooper 1981; Galton 1985a; Crompton & Attridge 1986; Gow et al. 1990; Barrett 2000; *Author for correspondence. E-mail: [email protected] Knoll 2005; Barrett & Upchurch 2007; Butler et al. 2013). Palaeontologia africana 53: 114–178 — ISSN 2410-4418 [Palaeontol. afr.] Online only Permanently archived on the 29th of April 2019 at the University of the Witwatersrand, Johannesburg, South Africa. The article and five supplements are permanently archived at: http://wiredspace.wits.ac.za/handle/10539/26829 114 ISSN 2410-4418 Palaeont. afr. (2019) 53: 114–178 Finally, due to the completeness of many referred speci- Lufengosaurus and Yunnanosaurus should be regarded as mens, M. carinatus is frequently included in phylogenetic junior synonyms of Massospondylus, vastly expanding the analyses of early sauropodomorph and early dinosaur geographic range of the genus, but the numerous differ- interrelationships (e.g. Yates 2004, 2007a; Smith & Pol ences between these taxa clearly support their generic 2007; Upchurch et al. 2007; Sertich & Loewen 2010; Yates separation (Young 1941, 1942; Galton & Upchurch 2004; et al. 2010; Apaldetti et al. 2011, 2013; Otero & Pol 2013; Barrett et al. 2005, 2007). These historical misidentifications Baron et al. 2017; Chapelle & Choiniere 2018). Most of result, at least in part, from the lack of published, compar- these recent works recover M. carinatus within a small, but ative information on Massospondylus specimens from the globally distributed, clade (the eponymous Massospon- type area. dylidae) that usually also includes Adeopapposaurus, Surprisingly, in spite of its prominence in palaeobiologi- Coloradisaurus, Glacialisaurus, Leyesaurus and Lufengo- cal, biostratigraphical and systematic studies, there has saurus, although clade membership varies between analy- been relatively little work on the anatomy and taxonomy ses. of Massospondylus carinatus and there have been few For many years it was assumed that M. carinatus was attempts to diagnose the taxon or to establish clear criteria the only sauropodomorph dinosaur from the upper for referring additional material to its hypodigm. Most Stormberg Group (Kitching & Raath 1984; Lucas & earlier descriptions were based on isolated remains whose Hancox 2001; Knoll 2005). However, a range of other taxa associations and exact provenance were unknown (e.g. spanning the sauropodomorph tree have now been Owen 1854; Seeley 1895a; von Huene 1906; Haughton named from this unit including Aardonyx celestae (Yates 1924), although a proliferation of new Massospondylus et al. 2010), Antetonitrus ingenipes (Yates & Kitching 2003), species names also appeared at this time (see Galton & Arcusaurus pereirabdalorum (Yates et al. 2011), Ignavusaurus Cluver [1976] and Cooper [1981] for reviews; see Discus- rachelis (Knoll 2010), M. kaalae (Barrett 2009) and Pulane- sion, below). There were few additional studies until saura eocollum (McPhee et al. 2015) (see review in McPhee more complete specimens were discovered from the 1960s et al. 2017). As a result, the former practice of referring all onward, primarily through the efforts of A.W.Crompton, sauropodomorph specimens recovered from the upper C.E. Gow and R.M.H Smith at the Iziko South African Stormberg Group to Massospondylus by default is no Museum, J.W.Kitching of the University of the Witwaters- longer tenable (Barrett 2004, 2009; Yates et al. 2004; rand and W.J.de Klerk of the Albany Museum, all working McPhee et al. 2017). in the main Karoo Basin of South Africa, with additional In addition to material from southern Africa, specimens collections being made from the upper Elliot and Clarens from other Late Triassic and Early Jurassic deposits formations of Lesotho by several French and Anglo/South elsewhere have been referred to Massospondylus, though African expeditions (e.g. Ellenberger et al. 1964; Attridge & not to M. carinatus. From India, these include the type Charig 1967; Anonymous 1969). Nevertheless, these new specimens of M. rawesi Lydekker, 1890a and M. hislopi discoveries did not spur any thorough treatments of the Lydekker, 1890a, from the Lameta Beds (Maastrichtian) taxon. Indeed, for several decades, the main published and Lower Maleri Formation (late Carnian–early Norian), source of information on M. carinatus was Cooper’s (1981) respectively. M. rawesi, represented by an isolated tooth, is monograph, which is based upon a variety of specimens currently regarded as a nomen dubium (an indeterminate collected from several different Zimbabwean localities theropod dinosaur; e.g. Carrano et al. 2010), whereas and formations. Although this became the standard M. hislopi, which was based on an isolated vertebra, lacks reference work on M. carinatus, it has not yet been demon- any features supporting its validity and is also regarded as strated that this Zimbabwean material is conspecific with a nomen dubium (Sauropodomorpha indet.: von Huene that