Bramatherium megacephalum Lydekker, 1876

Rios, M, Danowitz, M & Solounias, N, 2016, First comprehensive morphological analysis on the metapodials of Giraffidae, Palaeontologia Electronica 410 (10453), pp. 1-39 : 5

Bramatherium megacephalum Lydekker, 1876

Specimens. AMNH 29820, AMNH 9820 Description. There is a pronounced step between the medial and lateral facet at the articular surface. The synovial fossa is open, oval, and large. The medial and lateral epicondyles are asymmetrical in size and morphology, and strongly flare outward on the medial and lateral edges ( Figure 8 ). The medial and lateral epicondyles are separated centrally by a wide, deep groove. The articular surface extends onto the palmar surface of the lateral epicondyle. There is a longitudinal groove on the lateral surface of the lateral epicondyle, which continues down the lateral aspect of the lateral ridge ( Figure 4 ). The medial epicondyle is circle-sector shaped and larger, and the lateral epicondyle is smaller and triangular. There is a wide, deep fossa at the proximal edge of the medial epicondyle. There is an extra, elongated bony protrusion on the medial edge of the proximal shaft ( Figure 5.2 ). The medial ridge is rounded and extends from the medial epicondyle to the distal condyle. It is very prominent and full. The lateral ridge is sharper, and also extends from the lateral epicondyle to the distal condyle. The central trough is deep and continuous throughout the length of the metacarpal, but it becomes progressively flatter towards the distal edge. The keels of the distal condyles extend onto the palmar distal shaft.

Figures

FIGURE 4. Three selected metacarpal characteristics. This simplified table can be used to facilitate specimen identifications and differentiate between different giraffid taxa.

FIGURE 5. Palmar views of the right metacarpals (left) and plantar views of metatarsals (right) of certain Giraffidae. 1, Helladotherium duvernoyi, late Miocene, Pikermi, NHM 11382 (metacarpal), MNHNP 1554 (metatarsal) (both reversed); 2, Bramatherium megacephalum, late Miocene-Pliocene, Siwaliks, AMNH 29820, (metacarpal), AMNH 19668 (metatarsal); 3, Sivatherium giganteum, Pleistocene, Siwaliks, NHM 39553 (metacarpal), NHM 39752 (metatarsal); 4, Decennatherium pachecoi, late Miocene, Los Valles de la Fuentidueña, MNCN 42769 (metacarpal), MNCN 42764 (metatarsal) (both reversed); 5, Birgerbohlinia schaubi, late Miocene, Piera, IPS 5060 (metacarpal), Crusafont, 1952, fig. 15-5 (metatarsal), (both reversed); 6, Okapia johnstoni, Zaire, AMNH 51196 (metacarpal), AMNH 51196 (metatarsal). Scale bar equals 200 mm.

FIGURE 8. Bramatherium megacephalum from the Upper Siwaliks. 1, Right metacarpal AMNH 29820; 2, Right metatarsal AMNH 19688.