Multiple exostoses and an osteochondroma in a Pliocene canid from Langebaanweg 'E' Quarry (South Africa)

Langebaanweg is a Mio-Pliocene locality located on the West Coast of South Africa. It is renowned for its rich diversity of both terrestrial and marine vertebrate fossils. Several carnivorans have been identified from this site, amongst which is the recently described jackal-like canid, Eucyon khoikhoi. One of the skeletons assigned to E. khoikhoi exhibits anatomical deformities on several bones of the skeleton. Here, we use multiple methodologies (anatomical descriptions, CT scanning and histology) to investigate the bony overgrowths or exostoses evident in the radius, and we compare these findings with those of a radius from a healthy individual of the same species from Langebaanweg. Our results show that anatomical observations are important for first level observation of the pathology, but that micro-CT scanning permits a more precise assessment of how the pathology affected the internal organization of the bone, both periosteally and endosteally. This methodology permitted us to diagnose the tumors as benign rather than cancerous. Our observations of calcified cartilage in the histological thin sections in the region of the exostosis allowed us to further diagnose the exostosis as an osteochondroma. This study has demonstrated the usefulness of applying multiple techniques to characterize and diagnose pathological bony growths in a fossil canivoran. We have also demonstrated the usefulness of histological studies in permitting a more refined diagnosis of the exostosis as an osteochondroma.

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.

Osteohistology and palaeobiology of giraffids from the Mio-Pliocene Langebaanweg (South Africa)

The reconstruction of life history traits, such as growth rate, age at maturity and age at death can be estimated from the histological analysis of long bones. Here, we studied 20 long bones (metapodials, tibia and femora) of Sivatherium hendeyi and Giraffa cf. Giraffa jumae recovered from the Miocene-Pliocene locality of Langebaanweg on the West Coast of South Africa. We analysed the long bone histology and growth marks of juvenile and adult specimens of these taxa. Our results show that bone tissue types and vascular canal orientation varies during ontogeny, as well as between the different skeletal elements, and also across single cross sections of bones. Majority of our specimens appear to be still growing, with only an adult metacarpal of S. hendeyi being skeletally mature as indicated by the presence of an outer circumferential layer. We propose that the growth marks preserved in the cortices of the bones studied are most likely related to multiple catastrophic events as opposed to being annual/seasonal.