Decennatherium pachecoi 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 : 6-7

Decennatherium pachecoi Crusafont, 1952

Specimen. MNCN 42769

Description. The medial and lateral epicondyles are asymmetrical in size and morphology. The medial epicondyle is circle-sector shaped and flatter. The lateral epicondyle is triangular shaped and fuller, and the distal aspect continues onto the lateral ridge ( Figure 5.4 ). There is a small circular knob close to the median plane. An obliquely oriented groove separates the lateral epicondyle into a laterally flaring head that connects distally to the lateral ridge ( Figure 4 ). The proximal articular surface extends slightly onto the palmar surface of the lateral epicondyle. There is a shallow groove on the medial aspect of the medial epicondyle, which ends distally in the central trough. A deep, narrow groove separates the medial and lateral epicondyles and continues onto the central trough. The medial ridge is sharper, and it flattens towards the distal shaft, whereas the lateral ridge is rounder and it also flattens towards the distal shaft. There is an elongated oval fossa on the lateral aspect of the lateral ridge. The central trough is intermediate-deep in depth proximally ( Figure 7 ), and becomes progressively shallower and is flat distally. The lateral aspect of lateral distal condyle flares, whereas the medial aspect of the medial distal condyle is more vertical. The keels of the distal condyle continue slightly onto the palmar 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 7. Three additional metacarpal characteristics. This simplified table can be used to facilitate specimen identifications and differentiate between different giraffid taxa.