Samotherium major Bohlin, 1926

Rios, M, Danowitz, M & Solounias, N, 2016, First comprehensive morphological analysis on the metapodials of Giraffidae, Palaeontologia Electronica 410 (10453), pp. 1-39 : 18

Samotherium major Bohlin, 1926

Specimens. AMNH 22967, AMNH 22966 Description. The proximal articular surface exhibits three distinct facets. The lateral facet for the os naviculocuboideum is kidney-shaped. The medial facet for the os cuneiforme intermediolaterale is half-moon shaped and contacts the os cuneiforme mediale facet in a small point. On the lateral facet, there is a distinct constriction where the lateral ridge meets the lateral epicondyle. There is a bony protrusion medial to the separation of the large and small medial facets. The medial and lateral epicondyles are asymmetrical in size ( Figure 11 ). The lateral epicondyle is larger and has a fuller surface ( Figure 12.1 ). The medial epicondyle is separated into a plantar and a dorsal head by a longitudinal groove that continues down the medial aspect of the shaft. Both heads slightly flare outward ( Figure 16 ). The lateral epicondyle is separated into a dorsal and plantar head by a notably deep, wide groove. The plantar head is oriented longitudinally and the dorsal head flares outward. There is an elongated oval bony protrusion at the proximal medial shaft, which originates at the level of the proximal articular surface ( Figure 17). The medial and lateral ridges originate at the distal aspect of the plantar heads of the medial and lateral epicondyles. There is a deep groove that separates the medial and lateral epicondyles, which continues onto the central trough. The pygmaios is distinct from the proximal shaft by deep medial and lateral grooves, is rounded, curves medially, and protrudes proximally ( Figure 16 ). The medial and lateral ridges continue to just proximal to the distal condyles, where they abruptly flatten. They are both sharp. The central trough is intermediate in depth and flattens at the distal aspect of the shaft. The distal shaft flares laterally. The keels of the distal condyle continue slightly onto the plantar shaft.

Figures

FIGURE 11. Samotherium major from Samos. 1, Right metacarpal NHMBe 711; 2, Right metatarsal AMNH 22967.

FIGURE 12. Palmar views of the right metacarpals (left) and plantar views of the metatarsals (right) of certain Giraffidae. 1, Samotherium major, late Miocene, Samos, NHM Be Samos 711 (metacarpal), AMNH 22967 (metatarsal) (both reversed); 2, Palaeotragus rouenii, late Miocene, Pikermi, MNHNP 1692 (metacarpal), (reversed); MNHNP 1691 (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.