Lophiomeryx cf. chalaniati Pomel, 1854

Vianey-Liaud, Monique, Comte, Bernard, Marandat, Bernard, Peigné, Stéphane, Rage, Jean-Claude & Sudre, Jean, 2014, A new early Late Oligocene (MP 26) continental vertebrate fauna from Saint-Privat-des-Vieux (Alès Basin, Gard, Southern France), Geodiversitas 36 (4), pp. 565-622 : 607-608

Lophiomeryx cf. chalaniati Pomel, 1854

MATERIAL EXAMINED AND MEASUREMENTS (in mm). — One left P4: 10.4 × 10.7; one left p3, 12.6 × 5; talus, L = 61.

DESCRIPTION AND COMPARISONS

Ŋe P4, almost as long as wide, is remarked by its incipient molarization.Indeed, on the flat but slightly

concave ectoloph, the outer cusp begins to divide. Ŋe postprotocrista shows a particularly clear median bifurcation.Ŋe anterior cingulum is short and strong. Ŋe posterior cingulum, very strong also, stands up to the mid of the posprotocrista. Size and morphology of this specimen are the closest to those of the P4 of Lophiomeryx cf. chalaniati from Le Garouillas ( Sudre 1995).Among the rich material from this locality,some P4 show an early bifurcation of the postprotocrista, and a beginning of division of the outer cusp. However, none has a degree of molarization as advanced as that observed on the tooth of Saint-Privat-des-Vieux. Ŋis morphology is unknown in other selenodont artiodactyls from the mid-Oligocene confirming the more derived state of this form.Ŋe p3,very elongated and provided with a longitudinal ridge, has morphol - ogy consistent with that of L. cf. chalaniati from Le Garouillas ( Sudre 1995: fig. 14a, b).

A calcaneus is also reported to this form ( Fig. 16 ). Ŋe body is massive with a wide caput calcanei and the sustentaculum tali projecting medially and very thick rearwardly; the tendinous slide is flat medio-laterally and rounded dorsoventrally. Ŋe morphology of the surface suggests the important role of the tensio flexor of the phalanges. Ŋis is a configuration similar to that observed in the calcaneus of Lophiomeryx from Le Garouillas ( Sudre 1995: 231, fig. 16), the latter being slightly smaller (L mean = 58.6 mm); the size of the specimen from Saint-Privat-des-Vieux exceeds the maximum value recorded in the form of Le Garouillas. On the basis of the material of L. chalaniati from Le Garouillas, the distal ends of the appendicular skeleton of this species show short and robust metapodials, and metatarsals nearly as long as the metacarpals ( Sudre 1995). Ŋese features characterize a walking animal, and the species is probably dependent on soft soils, close to aquatic environments ( Trofimov 1957; Blondel 1998). Ŋe paleoecological study of the fauna from Le Garouillas suggests such an environmental context ( Legendre 1995).

With regard to the largest mammals known from Saint-Privat-des-Vieux, we can estimate the weight of the animal as about 25 kg if one refers to that established for L. cf. chalaniati from Le Garouillas ( Legendre 1995; Martinez & Sudre 1997).

Ŋe chronological extension of the lineage of Lophiomeryx , initiated at the beginning of the Oligocene ( L. mouchelini , at Villebramar, MP 21; Brunet& Sudre 1987) lasts up to the level MP 28. Ŋe last representative of the lineage is known from the site of Pech-Desse (MP 28a; Blondel 1996). Ŋe dental elements referred to the species chalaniati from localities more recent than Le Garouillas does not allow meaningful comparisons.

Figures

FIG. 16. — Right calcaneus of Lophiomeryx cf. chalaniati Pomel, 1853, from Saint-Privat-des-Vieux (Gard; Lower Chattian, MP 26), SPV700. A, lateral side; B, dorsal aspect; C, medial side. Abbreviations: ef, ectal facet; cc, caput calcanei; ssp, sustentacular pro- cess. Scale bar: 2.5 cm.