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 : 17

Birgerbohlinia schaubi Crusafont, 1952

Specimens. IPS 5015, IPS 5090, IPS 4981, MGUV 7788, MGUV 7803

Description. The proximal articular surface exhibits three distinct facets. The facet for the os naviculocuboideum is kidney-shaped. The facet for the os cuneiforme intermediolaterale is more oval and is separated from the os cuneiforme mediale facet, which is more triangular ( Figure 18.4 ). The medial and lateral epicondyles are asymmetrical in size and morphology ( Figure 5.5 ). The medial epicondyle is only slightly split into two heads by a shallow, obliquely oriented groove on the medial shaft. The plantar head has a full, rounded, elevated surface which is continuous with the medial ridge. There is a deep groove running obliquely on the lateral shaft, separating the lateral epicondyle into plantar and dorsal heads. The plantar head has a rounded surface which is continuous distally with the lateral ridge. In both the medial and lateral epicondyles, the plantar head is oriented longitudinally and the dorsal head flares outward ( Figure 16 ). The medial and lateral epicondyles are separated by a wide, deep groove. The lateral ridge is sharp, whereas the medial ridge is rounded. The central trough is very deep ( Figure 17). The keels of the distal condyles slightly extend onto the distal shaft.

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

FIGURE 18. Metatarsal proximal morphology. 1, Helladotherium duvernoyi, late Miocene, Pikermi, M 1138; 2, Bramatherium megacephalum, late Miocene-Pliocene, Siwaliks, AMNH 19688; 3, Decennatherium pachecoi, late Miocene, Los Valles de Fuentidueña, MNCN 42764; 4, Birgerbohlinia schaubi, late Miocene, Piera, IPS 5090. Abbreviations: NC, os naviculocuboideum facet; CIL, os cuneiforme intermediolaterale facet; CM, os cuneiforme mediale facet. Images not to scale.