Langebaanweg's sabertooth guild reveals an African Pliocene evolutionary hotspot for sabertooths (Carnivora; Felidae).

Here, we describe and revise craniodental material from Langebaanweg 'E' Quarry (South Africa, early Pliocene, ∼5.2 Ma), which represents one of the largest and best-preserved collections of sabertooth felids from Mio-Pliocene deposits of Africa. Four taxa, including two new species, are recognized: Lokotunjailurus chinsamyae sp. nov., Adeilosmilus aff. kabir, Yoshi obscura, and Dinofelis werdelini sp. nov. The felid guild composition analyzed herein suggests the presence of a mosaic environment with open components in the region, and shows a potential relationship with that of Yuanmou, suggesting a similar environment and/or dispersal route/event. The reassessment of the rich early Pliocene felids from Langebaanweg is a step toward understanding the transition and evolution of the felids in the southern hemisphere during the late Miocene to early Pliocene.

The exceptionally high diversity of small carnivorans from the Late Miocene hominid locality of Hammerschmiede (Bavaria, Germany).

The present study deals with new material of carnivorans (Mustelidae, Mephitidae, Ailuridae, Potamotheriinae and Viverridae) from the basal Tortonian (Late Miocene, late Astaracian) hominid-bearing locality of Hammerschmiede (Bavaria, Germany). The small carnivoran fauna includes 20 species belonging to nine different subfamilies (Guloninae, Lutrinae, Mellivorinae, Potamotheriinae, Leptarctinae, Mephitinae, Simocyoninae, Genettinae and Viverrinae). The identified forms include: "Martes" sansaniensis, "Martes" cf. munki, "Martes" sp., Circamustela hartmanni n. sp., Laphyctis mustelinus, Guloninae indet., Eomellivora moralesi, Vishnuonyx neptuni, Paralutra jaegeri, Lartetictis cf. dubia, Trocharion albanense, Palaeomeles pachecoi, Proputorius sansaniensis, Proputorius pusillus, Alopecocyon goeriachensis, Simocyoninae indet., Potamotherium sp., Semigenetta sansaniensis, Semigenetta grandis and Viverrictis modica. The new species Circamustela hartmanni n. sp. is differentiated from the other members of the genus by its small size and the morphology of its dental cusps in the upper and lower carnassials. This is one of the highest reported taxonomic diversities for fossil small carnivorans in the Miocene of Europe, including also first and last occurrences for several genera and species. Additionally, the assemblage comprises some rare taxa such as Palaeomeles pachecoi and Eomellivora moralesi. An ecomorphological comparison of the discovered taxa reveals possible cases of competition and niche partitioning.

New insights into the giant mustelids (Mammalia, Carnivora, Mustelidae) from Langebaanweg fossil site (West Coast Fossil Park, South Africa, early Pliocene).

Giant mustelids are a paraphyletic group of mustelids found in the Neogene of Eurasia, Africa and North America. Most are known largely from dental remains, with their postcranial skeleton mostly unknown. Here, we describe new craniodental and postcranial remains of the large lutrine Sivaonyx hendeyi and the leopard-size gulonine Plesiogulo aff. monspessulanus from the early Pliocene site Langebaanweg, South Africa. The new material of the endemic S. hendeyi, includes upper incisors and premolars, and fragmentary humerus, ulna and a complete astragalus. Its postcrania shares more traits with the living Aonyx capensis than the late Miocene Sivaonyx beyi from Chad. Sivaonyx hendeyi could therefore be tentatively interpreted as a relatively more aquatic taxon than the Chadian species, comparable to A. capensis. The new specimens of Plesiogulo comprise two edentulous maxillae, including one of a juvenile individual with incomplete decidual dentition, and a fragmentary forelimb of an adult individual. The new dental measurements point to this form being amongst the largest specimens of the genus. Both P3-4 differs from the very large species Plesiogulo botori from late Miocene of Kenya and Ethiopia. This confirms the existence of two distinct large species of Plesiogulo in Africa during the Mio/Pliocene, P. botori in the Late Miocene of Eastern Africa (6.1-5.5 Ma) and Plesiogulo aff. monspessulanus at the beginning of the Pliocene in southern Africa (5.2 Ma). Lastly, we report for the first time the presence of both Sivaonyx and Plesiogulo in MPPM and LQSM at Langebaanweg, suggesting that the differences observed from the locality may be produced by sedimentation or sampling biases instead of temporal replacement within the carnivoran guild.

Megalictis, the Bone-Crushing Giant Mustelid (Carnivora, Mustelidae, Oligobuninae) from the Early Miocene of North America.

We describe cranial and mandibular remains of three undescribed individuals of the giant mustelid Megalictis ferox Matthew, 1907 from the latest Arikareean (Ar4), Early Miocene mammal fauna of Nebraska, and Wyoming (USA) housed at the American Museum of Natural History (New York, USA). Our phylogenetic hypothesis indicates that Ar4 specimens assigned to M. ferox constitute a monophyletic group. We assign three additional species previously referred to Paroligobunis to Megalictis: M. simplicidens, M. frazieri, and "M." petersoni. The node containing these four species of Megalictis and Oligobunis forms the Oligobuninae. We test the hypothesis that Oligobuninae (Megalictis and Oligobunis) is a stem mustelid taxon. Our results indicate that the Oligobuninae form the sister clade to the crown extant mustelids. Based on the cranium, M. ferox is a jaguar-size mustelid and the largest terrestrial mustelid known to have existed. This new material also sheds light on a new ecomorphological interpretation of M. ferox as a bone-crushing durophage (similar to hyenas), rather than a cat-like hypercarnivore, as had been previously described. The relative large size of M. ferox, together with a stout rostrum and mandible made it one of the more powerful predators of the Early Miocene of the Great Plains of North America.

Tracing the origin of the panda's thumb.

We investigate the relative development of the carnivoran radial sesamoids to untangle the evolution of this iconic structure. In the pandas (both giant and red), this 'false thumb' is known to perform a grasping role during bamboo feeding in both the red and giant pandas. An original locomotor role has been inferred for ailurids, but this remains to be ascertained for ursids. A large sample of radial sesamoids of Indarctos arctoides from the Miocene of Batallones-3 (Spain) indicates that this early ailuropodine bear displayed a relatively hypertrophied radial sesamoid, with a configuration more similar to that of the red panda and other carnivorans than to that of giant pandas. This false thumb is the first evidence of this feature in the Ursidae, which can be linked to a more herbivorous diet. Moreover, in the two extant pandas, the false thumb should not be interpreted as an anatomical convergence, but as an exaptive convergence regarding its use during the bamboo feeding, which changes the evolutionary view of this singular structure.

On the socio-sexual behaviour of the extinct Ursid Indarctos arctoides: an approach based on its baculum size and morphology.

The fossil bacula, or os penis, constitutes a rare subject of study due to its scarcity in the fossil record. In the present paper we describe five bacula attributed to the bear Indarctos arctoides Depéret, 1895 from the Batallones-3 site (Madrid Basin, Spain). Both the length and morphology of this fossil bacula enabled us to make interpretative approaches to a series of ecological and ethological characters of this bear. Thus, we suggest that I. arctoides could have had prolonged periods of intromission and/or maintenance of intromission during the post-ejaculatory intervals, a multi-male mating system and large home range sizes and/or lower population density. Its size might also have helped females to choose from among the available males.

Kretzoiarctos gen. nov., the oldest member of the giant panda clade.

The phylogenetic position of the giant panda, Ailuropoda melanoleuca (Carnivora: Ursidae: Ailuropodinae), has been one of the most hotly debated topics by mammalian biologists and paleontologists during the last century. Based on molecular data, it is currently recognized as a true ursid, sister-taxon of the remaining extant bears, from which it would have diverged by the Early Miocene. However, from a paleobiogeographic and chronological perspective, the origin of the giant panda lineage has remained elusive due to the scarcity of the available Miocene fossil record. Until recently, the genus Ailurarctos from the Late Miocene of China (ca. 8-7 mya) was recognized as the oldest undoubted member of the Ailuropodinae, suggesting that the panda lineage might have originated from an Ursavus ancestor. The role of the purported ailuropodine Agriarctos, from the Miocene of Europe, in the origins of this clade has been generally dismissed due to the paucity of the available material. Here, we describe a new ailuropodine genus, Kretzoiarctos gen. nov., based on remains from two Middle Miocene (ca. 12-11 Ma) Spanish localities. A cladistic analysis of fossil and extant members of the Ursoidea confirms the inclusion of the new genus into the Ailuropodinae. Moreover, Kretzoiarctos precedes in time the previously-known, Late Miocene members of the giant panda clade from Eurasia (Agriarctos and Ailurarctos). The former can be therefore considered the oldest recorded member of the giant panda lineage, which has significant implications for understanding the origins of this clade from a paleobiogeographic viewpoint.