Postcranial Material Research Articles

Edentulous pterosaurs from the Cambridge Greensand (Cretaceous) of eastern England with a review of Ornithostoma Seeley, 1871

A re-examination of fossil material from the Late Cretaceous Cambridge Greensand Member (CGM) of the West Melbury Marly Chalk Formation revealed a number of new specimens of edentulous pterosaur jaw fragments previously identified as shark fin spines and fish jaws and accessioned under the epithet ‘cestraciontid finray’ and ‘jaws of fish’. These are now recognised as pterosaurian jaw tips and referred to Ornithostoma sedgwicki Seeley, 1891 and Azhdarchoidea indet. This material increases the diversity of edentulous pterosaurs from the CGM.The edentulous pterosaur Ornithostoma sedgwicki Seeley, 1891 from the Cretaceous Cambridge Greensand of eastern England is reviewed. The holotype specimen is confirmed as a fragment of a premaxilla/maxilla of a non-tapejarid azhdarchoid on account of the conspicuous curvature of the dorsal and occlusal margins posteriorly and the presence of small neural foramina on the lateral margins. Neural foramina are not seen on jaws of members of the Pteranodontia, a group to which O. sedgwicki was included previously. The referral of O. sedgwicki to Azhdarchoidea eliminates the single known Lower Cretaceous occurrence of Pteranodontidae, restricting the temporal range of this taxon to the Upper Cretaceous. Postcranial material referred to O. sedgwicki from the type horizon is regarded as indeterminate Pterosauria.

Postcranial skeleton of Spalacopus cyanus (Rodentia: Octodontidae): description and functional aspects

The genus Spalacopus includes only one species, S . cyanus , endemic to central Chile and one of the species best adapted to a subterranean lifetyle in the family Octodontidae. It is a member of the lineage consisting in Octodontomys as a sister clade containing Octodon and of a clade represented by Spalacopus and Aconaemys . Although the external and cranio-dental morphology have been well studied, little is known of the postcranial morphology of S . cyanus . Because of the peculiarities of its lifestyle and locomotion among the members of the family, it is interesting to characterize details of the morphology of the postcranial skeleton of this species and to infer their functional aspects of the morphology. Twenty-nine specimens with postcranial material stored in two collections were studied: Museo de La Plata (MLP), La Plata, Buenos Aires, Argentina and Coleccion de Mamiferos del Instituto de Ciencias Ambientales y Evolutivas (UACH), Universidad Austral de Chile, Valdivia, Chile. To describe in detail the morphology of the bone elements, the skeleton was divided in the following regions: axial skeleton, scapular girdle and forelimb, and pelvis girdle and hindlimb. The structures included in the axial skeleton were mainly described in cranial-caudal orientation and the limbs in proximal-distal orientation. All structures were observed with stereoscopic microscopes Leica Wild M3Z and Nikon SMZ 745T including pictures to illustrate the descriptions. Highly conservative characteristics among members of the family Octodontidae were observed in the postcranial morphology of S . cyanus , although some characters are exclusive to this species. The axial skeleton has seven cervical vertebrae, 12 or 13 thoracic, six or seven lumbar, four sacral, 16 to 18 caudal vertebrae, 12 or 13 ribs and a sternum with five sternebrae. The elements of the scapular and pelvic girdles as well as forelimbs and hindlimbs are described in detail, except the carpus and tarsus due to their poor state of conservation, or because they not available. The morphological pattern observed in the postcranial skeleton of S . cyanus conforms to a typical anatomical plan for terrestrial species, and some bones (mainly humerus and ulna) present characteristics associated with digging. The information obtained provided will allow a better interpretation of the postcranial attributes, functionally related with different lifestyle, in a future, as well as the evolution of the traits in a phylogenetic context.

Life and death of the ground sloth Xibalbaonyx oviceps from the Yucatán Peninsula, Mexico

ABSTRACT Ongoing investigations in submerged cave systems of Quintana Roo in south-eastern Mexico reveal a rich Late Pleistocene megafaunal assemblage, among them the megalonychid ground sloth Xibalbaonyx oviceps. The taxon has been described based on a complete skull and mandible from El Zapote cenote west of Puerto Morelos. We here add hitherto unreported postcranial material from El Zapote, attributed to the holotype. This new material allows us to reconstruct unexpected locomotion capabilities for Xibalbaonyx oviceps including steep slope and rock climbing. This may have enabled the ground sloth to use the sinkholes and underground caverns as water resource and shelter. The Late Pleistocene age of the fossil allows for a co-existence with early human settlers on the Yucatán Peninsula.

A highly pneumatic middle Cretaceous theropod from the British Lower Greensand

AbstractA series of axial elements from the Aptian Ferruginous Sands Formation of the Lower Greensand Group, discovered on the foreshore near Knock Cliff on the Isle of Wight, UK are (bar some isolated teeth and fragmentary postcranial material from the Cenomanian Cambridge Greensand) the youngest non‐avian theropod remains reported from the British Mesozoic. These specimens have the potential to shed light on a poorly known section of the European dinosaur record. Consistency in size, appearance and adhering matrix indicates that the vertebrae belong to the same individual. This was a mid‐sized tetanuran, the presence of several diagnostic characters indicating that it should be recognized as a new taxon, herein named Vectaerovenator inopinatus. The cervical and dorsal vertebrae are camerate and highly pneumatic. Tetanuran features include opisthocoelous cervicals and pneumatic foramina located within fossae; however, assigning this specimen to a specific clade is problematic. Within Tetanurae, Vectaerovenator possesses axial structures and homoplastic features seen in megalosauroids, carcharodontosaurians and certain coelurosaurs. Not only is Vectaerovenator one of the UK's youngest non‐bird dinosaurs, and one of few valid British Greensand taxa, it is also the first diagnosable theropod taxon to be named from Aptian deposits of Europe.

Evolution of arboreality and fossoriality in squirrels and aplodontid rodents: Insights from the semicircular canals of fossil rodents.

Reconstructing locomotor behaviour for fossil animals is typically done with postcranial elements. However, for species only known from cranial material, locomotor behaviour is difficult to reconstruct. The semicircular canals (SCCs) in the inner ear provide insight into an animal's locomotor agility. A relationship exists between the size of the SCCs relative to body mass and the jerkiness of an animal's locomotion. Additionally, studies have also demonstrated a relationship between SCC orthogonality and angular head velocity. Here, we employ two metrics for reconstructing locomotor agility, radius of curvature dimensions and SCC orthogonality, in a sample of twelve fossil rodents from the families Ischyromyidae, Sciuridae and Aplodontidae. The method utilizing radius of curvature dimensions provided a reconstruction of fossil rodent locomotor behaviour that is more consistent with previous studies assessing fossil rodent locomotor behaviour compared to the method based on SCC orthogonality. Previous work on ischyromyids suggests that this group displayed a variety of locomotor modes. Members of Paramyinae and Ischyromyinae have relatively smaller SCCs and are reconstructed to be relatively slower compared to members of Reithroparamyinae. Early members of the Sciuroidea clade including the sciurid Cedromus wilsoni and the aplodontid Prosciurus relictus are reconstructed to be more agile than ischyromyids, in the range of extant arboreal squirrels. This reconstruction supports previous inferences that arboreality was likely an ancestral trait for this group. Derived members of Sciuridae and Aplodontidae vary in agility scores. The fossil squirrel Protosciurus cf. rachelae is inferred from postcranial material as arboreal, which is in agreement with its high agility, in the range of extant arboreal squirrels. In contrast, the fossil aplodontid Mesogaulus paniensis has a relatively low agility score, similar to the fossorial Aplodontia rufa, the only living aplodontid rodent. This result is in agreement with its postcranial reconstruction as fossorial and with previous indications that early aplodontids were more arboreal than their burrowing descendants.

The osteology of the early-diverging dinosaurDaemonosaurus chauliodus(Archosauria: Dinosauria) from theCoelophysisQuarry (Triassic: Rhaetian) of New Mexico and its relationships to other early dinosaurs

AbstractThe early evolution of dinosaurs is documented by abundant postcranial material, but cranial material is much rarer and comparisons of cranial features among early dinosaurs are limited to only a few specimens. Here, we fully detail the osteology of the unusual early-diverging dinosaur Daemonosaurus chauliodus from the latest Triassic Coelophysis Quarry in northern New Mexico, USA. The taxon possesses a unique and curious suite of character states present in a variety of early dinosaurs, and the morphology of D. chauliodus appears to link the morphology of Herrerasaurus with that of later diverging eusaurichians. Our phylogenetic analyses places D. chauliodus at the base of dinosaurs and our interpretation of the unusual mix of character states of D. chauliodus does not lead to a firm conclusion about its nearest relationships or its implications for the evolution of character state transitions at the base of Dinosauria. The combination of character states of D. chauliodus should not be ignored in future considerations of character evolution in early dinosaurs. As one of the last members of the earliest radiation of saurischians in the Carnian–early Norian, D. chauliodus demonstrates that members of the original diversification of dinosaurs survived until nearly the end of the Triassic Period.

Paleocene resurrection of a crocodylomorph taxon: Biotic crises, climatic and sea level fluctuations

Postcranial material of a crocodylomorph from the Danian of Oulad Abdoun Basin (Morocco) is described. Several characters, in particular the shape of its dorsal osteoderms, allows its attribution to Pholidosauridae. Up till now, the latest known pholidosaurid was Terminonaris, from the Early Turonian of North America, so, the Moroccan pholidosaurid extends the stratigraphic range of the group to more than 20 million years younger, and shows that the pholidosaurids survived the K-Pg crisis. The reevaluation and the phylogenetic analysis of Dakotasuchus kingi, Woodbinesuchus byersmauricei, and Sabinosuchus coahuilensis, previously considered as goniopholidids and dyrosaurid, respectively, revealed rather that they are pholidosaurids. This analysis also suggests that at least two independent pholidosaurid lineages reached the Maastrichtian, among which one crossed the K-Pg boundary. This study proposes the first analysis of tethysuchian diversity from the Late Jurassic to the Early Paleogene. Two diversity peaks are observed during the Oxfordian and Cenomanian, two stages of high paleotemperatures evaluated with the δ18O. The tethysuchian diversity strongly decreases after the Cenomanian, a decline that may be correlated with the “Ocean Anoxic Event” (OAE 2), which caused the strong marine faunal turnover during the Cenomanian-Turonian time interval. The large Turonian-Coniacian oceanic regression could also be a factor in the tethysuchian decline. After that, tethysuchian diversity remains low until the Maastrichtian-lower Paleocene marine tethysuchian dyrosaurid diversification, correlated with the Late Cretaceous-Paleocene transgression. At least one pholidosaurid lineage crossed the K-Pg boundary, confirming the weak impact of this crisis on the crocodylomorphs. Pholidosaurids seem to go extinct at the beginning of the Paleocene, possibly due to the strong radiation of dyrosaurids in marine environments and crocodylians in fresh-water during this time period.

Large ungulates from the basal Oligocene of Oman: 1 – Embrithopoda

Arsinoitheres (Embrithopoda, Mammalia) have been known to occur in the Early Oligocene of Oman since 1992, yet the fossils on which the records were based have not yet been published. This contribution rectifies this situation and provides the first secure basis for the presence of arsinoitheres in Oman, some post-cranial material previously attributed to this genus being of uncertain affinities. The Omani records and the one in the Shumaysi Formation, Saudi Arabia, extend the distribution of Arsinoitherium adrewsi to the northeastern extremities of the Afro-Arabian Continent

Skeleton of aCretaceous mammal from Madagascar reflects long-term insularity.

The fossil record of mammaliaforms (mammals and their closest relatives) of the Mesozoic era from the southern supercontinent Gondwana is far less extensive than that from its northern counterpart, Laurasia1,2. Among Mesozoic mammaliaforms, Gondwanatheria is one of the most poorly known clades, previously represented by only a single cranium and isolated jaws and teeth1-5. As a result, the anatomy, palaeobiology and phylogenetic relationships of gondwanatherians remain unclear. Here we report the discovery of an articulated and very well-preserved skeleton of a gondwanatherian of the latest age (72.1-66million years ago) of the Cretaceous period from Madagascar that we assign to a new genus and species, Adalatherium hui. To our knowledge, the specimen is the most complete skeleton of a Gondwanan Mesozoic mammaliaform that has been found, and includes the only postcranial material and ascending ramus of the dentary known for any gondwanatherian. A phylogenetic analysis including the new taxon recovers Gondwanatheria as the sister group to Multituberculata. The skeleton, which represents one of the largest of the Gondwanan Mesozoic mammaliaforms, is particularly notable for exhibiting many unique features in combination with features that are convergent on those of therian mammals. This uniqueness is consistent with a lineage history for A.hui of isolation on Madagascar for more than 20million years.

A new cymbospondylid ichthyosaur (Ichthyosauria) from the Middle Triassic (Anisian) of the Augusta Mountains, Nevada, USA

A new taxon, Cymbospondylus duelferi sp. nov., is described from the late Anisian of the Fossil Hill Member of the Favret Formation of the Augusta Mountains, Pershing County, Nevada, USA. The holotype and only specimen consists of a fairly complete skull associated with articulated and disarticulated postcranial material. Body length reconstruction revealed a medium-sized individual with an estimated body length of 4.3 m. Dorsal vertebrae as well as the left humerus of this specimen are associated with three strings of articulated tail and posterior dorsal vertebrae, which are on average 68% smaller than the vertebrae of the medium-sized individual. Due to the small size of these vertebrae and their position within the trunk region, they most likely represent fetuses. Cymbospondylus duelferi sp. nov. provides the second-oldest evidence for viviparity in ichthyosaurs. In the course of this study, the skull morphology of C. petrinus and C. nichollsi was reviewed, resulting in revised character scorings for both. Phylogenetic analyses demonstrate a sister-taxon relationship of the new taxon with C. petrinus, which was found in the same stratigraphic unit, the Fossil Hill Member, that also crops out at the classical Fossil Hill locality in the Humboldt Range, where the member is part of the Prida Formation. Cymbospondylus duelferi sp. nov. shares a very similar skull morphology with C. petrinus and C. nichollsi, whereas the shoulder girdle morphology differs. Because there is no evidence for ontogenetic differences or sexual dimorphism in the new specimen, a third species of Cymbospondylus – neglecting the type species C. piscosus that is only known from five vertebrae – is recognized from the Fossil Hill Member. Further occurrences of the genus in the Lower and Middle Triassic of Svalbard (Boreal Ocean) and Europe (Tethys) point to a very fast radiation and dispersal of cymbospondylids during the Middle Triassic.https://zoobank.org:pub:906F5F32-9090-496D-8FC7-680D25EED5EF

A new species of Bottosaurus (Alligatoroidea: Caimaninae) from the Black Peaks Formation (Palaeocene) of Texas indicates an early radiation of North American caimanines

Abstract Morphological and molecular data suggest a close relationship for alligators and caimans. The first fossil appearances combined with phylogenetic hypotheses suggest a divergence of the groups near the Cretaceous–Palaeogene boundary, but the early fossil record of Caimaninae is incomplete, and large gaps exist between the earliest representatives of the group. A new caimanine from lower Palaeocene (Tiffanian) deposits in the Black Peaks Formation of Brewster County, Texas is established upon two specimens of different size that bear similarities to Bottosaurus harlani from the uppermost Cretaceous and lowermost Palaeogene of New Jersey. The larger individual consists of a partial skull and lower jaw in addition to postcranial material. The smaller individual preserves a snout and posterior portions of the skull. Both specimens suggest an animal with a comparatively short, flat, broad snout. Species of Bottosaurus share diagnostic morphological character states but are differentiated in meaningful ways. Phylogenetic analysis shows that the new species is sister to B. harlani, indicates an early radiation of North American caimanines and elucidates a more complicated biogeographical history than previously hypothesized. A growing body of evidence suggests that Caimaninae may be diagnosed by ancestral characters, potentially drawing basal alligatoroids crownwards in phylogenetic trees.

A New Species of Megalichthys (Sarcopterygii, Megalichthyidae) from the Upper Devonian (Famennian) of Pennsylvania, U.S.A., and a Report on the Cosmine-Covered Osteolepiform Fossils of the Catskill Formation

ABSTRACT New material from the Upper Devonian (Famennian) Catskill Formation of Pennsylvania, U.S.A., indicates the presence of a new species of Megalichthys. A large collection of complete and well-preserved fossil material from the Red Hill field locality enables a thorough anatomical description that is not commonly available in Megalichthyidae. The cranial material includes skull roof, partial cheek, lower jaw, opercular-gular elements, palatoquadrate, and dermal palatal elements. The postcranial material includes pectoral fin elements including cleithrum, mesomeres, and lepidotrichia; pelvic fin including lepidotrichia; and body scales in articulation. The new species is distinguished from other species of Megalichthys by the presence of a pineal series of bones, a triangular-shaped principal gular, and a lack of sensory canal pores on the postparietal. We review the taxonomic history and status of Megalichthyidae and Megalichthys and provide revised diagnoses for each that include only discrete features demonstrated to be sufficient for taxonomic assignment. We discuss additional cosmine-covered osteolepiform fossils from other Catskill Formation exposures. These include the type and only specimen of Sterropterygion brandei and seven new specimens (including a partial snout, a partial parietal shield, a partial postparietal shield, a partial cheek, and complete lower jaws) that potentially represent megalichthyid species in addition to the one at the focus of this study. With this description of new megalichthyid material, the Catskill Formation continues to produce, in some cases, the only known Devonian occurrence of otherwise younger taxa.

Cranial and postcranial remains of a new species of Prochelidella (Testudines: Pleurodira: Chelidae) from ‘La Buitrera’ (Cenomanian of Patagonia, Argentina), with comments on the monophyly of this extinct chelid genus from southern Gondwana

The genus Prochelidella is the oldest known panchelid taxon. It is widely distributed in several Cretaceous basins throughout Patagonia, Argentina. It was previously known from three named species. A fourth species presented herein, Prochelidella buitreraensis sp. nov., preserves both cranial and postcranial material from the Candeleros Formation (La Buitrera Area) of Río Negro Province, Argentina. Features observed in the nuchal bone (i.e. wide, trapezoidal cervical vertebrae, shallow nuchal notch) allow us to assign this specimen to the genus Prochelidella. Several specific traits (i.e. a large open retropterygoideum foramen, and a strongly developed muscle attachment site on the basisphenoid) suggest that the form from the Candeleros Formation is a new species of the genus Prochelidella. A phylogenetic analysis that includes the three best-preserved species of Prochelidella recovers this taxon as monophyletic. The Cenomanian age of this new taxon allows us to compare the panchelid turtles from the Patagonian (Neuquen) and Australian (Surat) basins.http://zoobank.org/urn:lsid:zoobank.org:pub:E9D194C7-126D-46B6-BF75-BD1A51A74971

New embolomerous tetrapod material and a faunal overview of the Mississippian-aged Point Edward locality, Nova Scotia, Canada

Embolomerous tetrapods, moderately-sized to large aquatic predators, form a major faunal constituent of Permo-Carboniferous tetrapod communities. Embolomeres are recognized by their distinct circular, bipartite vertebrae. Although traditionally classified as stem amniotes, the inclusion of embolomeres within the tetrapod crown group has recently been challenged. Despite the group’s phylogenetic uncertainty, embolomeres provide an important record of a long-lived tetrapod lineage, spanning “Romer’s Gap” through to the early Permian. Here, we describe embolomerous tetrapod material that was collected in 1915 by W.A. Bell (CMN 10015, herein divided into CMN 10015A, 10015B, and 10015C). The material, composed of numerous disarticulated cranial and postcranial elements, was discovered near Sydney, Nova Scotia, Canada, as ex situ beach-float pertaining to a horizon within the Mississippian-aged Point Edward Formation. Among this material, a single left lower jaw of a proterogyrinid is identified, differing from previous embolomere remains from this site identified as Pholiderpeton(?) bretonensis Romer, 1958. We also identify an anterior jaw fragment as a separate taxon from the proterogyrinid, indicating the presence of at least two embolomerous tetrapods in Bell’s collection. Other cranial and postcranial material cannot be directly associated with either jaw and are not diagnostic enough to assign to a specific taxon. Thus, the remaining material is referred to Embolomeri indet. until more information is available. Additionally, we summarize the fauna of the Point Edward locality revealing a diverse aquatic Late Mississippian ecosystem. Finally, the extensive embolomere material described here presents new data that can broadly address embolomere diversity throughout the Carboniferous.

Fósseis em uma frente de extração de mármore? Análises tafonômica e paleoicnológica de mamíferos de grande porte do Quaternário do Espírito Santo, Brasil

The occurrence of fossil mammals in the State of Espirito Santo is rare, with only two records, both reported to sediments localized within marble quarries in the district of Itaoca, in the Municipality of Cachoeiro de Itapemirim. The first record dates from 1978, when fossils of Eremotherium and gomphotheres were collected together with other vertebrate fossils and posteriorly described. The second dates from 1983, with the description of fossils of Eremotherium in an abstract. Part of this latter finding is housed at the Federal University of Espirito Santo (UFES) and represents the only fossil mammals from the State that are currently available for study. It comprises15 specimens, including cranial and post-cranial material. From these, eight can be referred to Eremotherium, one to Toxodontinae, one to Notiomastodon, and the others to large-bodied mammals. Fossils of Eremotherium and of indeterminate mammals are compatible with the presence of one giant ground sloth individual. Taphonomic and paleoichnological analyses of this supposed individual show that after death carnivores scavenged the carcass and that the bones were exposed to weathering for a relatively short time until they were transported by a hydraulic flow to a crevice, thus explaining the unusual finding of fossils in this particular outcrop.

The large American opossum Didelphis (Didelphimorphia, Didelphidae) in the Late Pleistocene of Uruguay, and paleoecological remarks

The fossil record of the genus Didelphis, despite its current diversity (6 species, 5 occurring in South America) and wide distribution (from southern Canada to Patagonia, Argentina), is very scarce. The oldest record of the genus in South America comes from Late Miocene sediments and the youngest records from the Late Holocene and historical times. In Uruguay, the only record is stratigraphically questionable because the material has been lost. The present contribution describes the first materials with a precise stratigraphic context assigned to Didelphis cf. D. albiventris, based on comparative morphological and numerical analysis. The materials were unearthed from several outcrops of the Sopas Formation (Late Pleistocene, northern Uruguay) and consist of an associated skull and mandible, right hemimandible, and postcranial material. These findings allow us to discuss several aspects related to the biology and ecology of Didelphis. These animals, which exhibit a mixed diet, were able to feed at intermediate levels of the food chain in highly diverse environments during the Late Pleistocene.

A new species of the carnivorous cynodont Chiniquodon (Cynodontia, Chiniquodontidae) from the Namibian Triassic

ABSTRACT Chiniquodontidae is a family of Triassic carnivorous cynodonts well represented in the Middle–Upper Triassic of Argentina and Brazil and, more recently, discovered in Madagascar and central Namibia. The Namibian specimen was found in the uppermost levels of the upper Omingonde Formation and is represented by the skull and partial skeleton. In this contribution, we provide a diagnosis for Chiniquodon omaruruensis, sp. nov., describe the postcranial material, and compare it with that of South American Chiniquodon specimens. Chiniquodon omaruruensis provides the first evidence of elements from the pes in Chiniquodon, and one of the few for non-mammaliaform cynodonts. Chiniquodon omaruruensis has a remarkably large calcaneus with an incipiently differentiated tuber, metatarsal II lateromedially robust but remarkably shorter than metatarsal IV, and an almost quadrangular basal phalanx in digit III. Similar to other Chiniquodon species, it lacks costal plates on ribs and shows a tall and slender scapular blade, a large acromion process positioned well above the scapular neck, and the absence of disc-like phalanges in the autopodium.

The postcranial anatomy of Endothiodon bathystoma (Anomodontia, Therapsida)

ABSTRACT Dicynodonts were herbivorous non-mammalian synapsids that were relatively abundant on the landmass of Pangea from the Mid Permian to Late Triassic. The dicynodont genus Endothiodon is well known from late Permian strata of the Karoo Basin of South Africa. It is characterised by replacement waves of internal tooth rows on the premaxilla and dentary; longitudinal ridges from the premaxilla to the pineal crest; and a pineal foramen on a prominent boss. Endothiodon is well-represented by cranial and postcranial material in various South African museum collections. Recently, an almost complete skeleton of Endothiodon (SAM-PK-K011271) was recovered from the uppermost Pristerognathus Assemblage Zone of the Karoo Supergroup. It comprises the skull and most postcranial elements preserved in articulation. The present study identifies SAM-PK-K011271 as E. bathystoma and we show that it is the second largest E. bathystoma specimen known to date. Furthermore, the well-preserved skeletal remains enable us to present the first comprehensive description of its postcranial anatomy. Abbreviations Institutional abbreviations: AM: Albany Museum, Grahamstown, South Africa; CGS: Council for Geosciences, Pretoria, South Africa; ESI: Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa; ISI: Indian Statistical Institute, Kolkata, India; SAM: Iziko South African Museum, Cape Town, South Africa.Anatomical abbreviations: ang, angular; art, articular; ast, astragalus; br, M. brachialis; c, centrale; ca, calcaneum; cb, M. coracobrachialis; cbl, M. coracobrachialis longus; Cd, caudal vertebra; d, dentary; del, M. deltoideus; ent, entepidcondyle; ent f, entepicondylar foramen; f, frontal; fti, M. femorotibialis; H, height; ife, M. iliofemoralis; ifi, M. iliofibularis; it, M. incisura tibialis fossa; iti, M. iliotibialis; il, ilium; is, ischium; j, jugal; l, lacrimal; M., metacarpal; mf, mandibular fenestra; Mt., metatarsal; n, nasal; nc, neural canal; ns, neural spine; ol, olecranon; P., phalanx; pb, pineal boss; pec, M. pectoralis; pifi, M. puboischiofemoralis internus; piti, M. puboischiotibialis; pm, premaxilla; po, postorbital; poz, postzygapophyses; prz, prezygapophyses; pp, preparietal; psf, postspinal fossa; pu, pubis; q, quadrate; r con, radial condyle; ref. l, reflected lamina; S, sacral vertebra; sas, M. serratus anterior superficialis; sc, M. subcoracoideus; scs, M. subcoracoscapularis; sha, M. scapulohumeralis anterior; SL, skull length; spc, M. supracoracoideus; sq, squamosal; sup, supinator; SW, skull width; tha, M. triceps humeralis anterior; thm, M. triceps humeralis medialis; tp, transverse process; tri, M. triceps; W, width.

Simbakubwa kutokaafrika, gen. et sp. nov. (Hyainailourinae, Hyaenodonta, ‘Creodonta,’ Mammalia), a gigantic carnivore from the earliest Miocene of Kenya

ABSTRACTHyainailourine hyaenodonts are among the largest terrestrial carnivorous mammals known. The clade is widely dispersed, found in Eurasia, North America, and Afro-Arabia in the Paleogene and early Neogene. In this study, we describe dental and postcranial material from Simbakubwa kutokaafrika, gen. et sp. nov., the most complete hyainailourine known from sub-Saharan Africa. The material is from a relatively young adult from the early Miocene locality of Meswa Bridge, Kenya. Simbakubwa differs from Hyainailouros in exhibiting lingually oriented molar protocones, gracile metastyles, and buccolingually compressed, shearing canines. Like other large Miocene hyainailourines, Simbakubwa has deep carnassial notches on the molars and tall paracones fused to shorter metacones forming single piercing cusps. A Bayesian phylogenetic analysis recovers Simbakubwa as the sister taxon of a clade of large-bodied Miocene hyainailourines that includes Hyainailouros and Megistotherium. Bayesian ancestral state reconstruction supports an Afro-Arabian origin for Hyainailourinae with subsequent dispersal to Eurasia during the early Miocene. Regression analysis based on carnassial size is applied to Simbakubwa and closely related hyainailourines, recovering a body mass up to 1,500 kg for the new taxon. The evolution and extinction of Hyainailourinae offers important insights for interpreting ecological transitions from Paleogene to Neogene faunas in Afro-Arabia and Eurasia.

Excavation, reconstruction and taphonomy of the StW 573 Australopithecus prometheus skeleton from Sterkfontein Caves, South Africa

Postcranial bones may provide valuable information about fossil taxa relating to their locomotor habits, manipulative abilities and body sizes. Distinctive features of the postcranial skeleton are sometimes noted in species diagnoses. Although numerous isolated postcranial fossils have become accepted by many workers as belonging to a particular species, it is worthwhile revisiting the evidence for each attribution before including them in comparative samples in relation to the descriptions of new fossils, functional analyses in relation to particular taxa, or in evolutionary contexts. Although some workers eschew the taxonomic attribution of postcranial fossils as being less important (or interesting) than interpreting their functional morphology, it is impossible to consider the evolution of functional anatomy in a taxonomic and phylogenetic vacuum. There are 21 widely recognized hominin taxa that have been described from sites in Africa dated from the Late Miocene to the Middle Pleistocene; postcranial elements have been attributed to 17 of these. The bones that have been thus assigned range from many parts of a skeleton to isolated elements. However, the extent to which postcranial material can be reliably attributed to a specific taxon varies considerably from site to site and species to species, and is often the subject of considerable debate. Here, we review the postcranial remains attributed to African hominin taxa from the Late Miocene to the Middle and Late Pleistocene and place these assignations into categories of reliability. The catalog of attributions presented here may serve as a guide for making taxonomic decisions in the future.