Birgerbohlinia schaubi Crusafont, 1952

Rios, M, Danowitz, M & Solounias, N, 2016, First comprehensive morphological analysis on the metapodials of Giraffidae, Palaeontologia Electronica 410 (10453), pp. 1-39 : 7

Birgerbohlinia schaubi Crusafont, 1952

Specimens. IPS 935, IPS 7640, IPS 5059, IPS 5060, IPS 5014, IPS 7629, IPS 5010, IPS 5061, MGUV 7806, AMNH 20610

Description. The synovial fossa is open and is oval in shape ( Figure 10 ). The step between the two facets is thin and well-marked. The medial and lateral epicondyles are asymmetrical. The medial epicondyle is more prominent and square. The lateral epicondyle is triangular in shape, is less developed, and has a fossa close to the articular surface (proximodorsal) ( Figure 5.5 ). The lateral epicondyle continues onto the palmar lateral ridge. There is a well-developed proximal dorsal tuberosity. The medial ridge is rounded and the lateral ridge is sharp. They create a deep central trough that flattens two-thirds down the shaft ( Figure 6.2 ). Both the medial and lateral ridges are rounded proximally and become progressively flatter distally. The distal shaft flares more on the medial edge. The keel of the distal condyles slightly extends onto the palmar distal shaft. The articular edge is vertical.

Figures

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 6. Representative cross sections of right metacarpals. 1, Helladotherium duvernoyi, late Miocene, Pikermi, MNHNP 1527; 2, Birgerbohlinia schaubi, late Miocene, Samos, AMNH 20610 (reversed); 3, Okapia johnstoni, AMNH 15218 (reversed); 4, Samotherium major, late Miocene, Samos, AMNH 22790; 5, Bohlinia attica, late Miocene, Pikermi, PA 1474-1991; 6, Giraffa camelopardalis, AMNH 70016. Scale bar equals 80 mm.

FIGURE 10. Metacarpal proximal morphology. Birgerbohlinia schaubi, late Miocene, Samos, AMNH 20610. Abbreviations: HA, os hamatum facet; TC, os trapezoideocapitatum facet; S, synovial fossa. Image not to scale.