Morphotype a

Fournier, Morgane, Ladevèze, Sandrine, Verger, Kévin Le, Fischer, Valentin, Speijer, Robert P. & Solé, Floréal, 2020, On the morphology of the astragalus and calcaneus of the amphicyonids (Carnivora, Mammalia) from the Paleogene of Europe: implications for the ecology of the European bear-dogs, Geodiversitas 42 (18), pp. 305-325 : 316

Morphotype A ( Fig. 4 A-E)

Dorsal view

The sagittal groove is rather marked. The proximal part of the tuber calcanei is rather mediolaterally wide. It is rather proximodistally elongated, as is the ectal facet. This facet is highly convex. Its edges are rather well pronounced, except the distal one, which merges with the body of the calcaneus (and therefore is difficult to delimit). The sustentacular facet is well-rounded, very slightly concave, and extends on the proximal edge of the sustentaculum tali. The peroneal process is quite broad and its proximal edge is well-defined. The cuboid facet is inclined with respect to the mediolateral axis and its lateral edge rises slightly on the body of the calcaneus. This articular surface is strongly concave.

Lateral view

The dorsal and ventral edges of the tuber calcanei are slightly concave. A cavity – probably for the insertion of the lateral collateral ligament – is clearly visible proximal to the ectal facet.

Medial view

The tendinous plantar groove is well excavated. The sustentaculum tali is dorsoventrally quite thick, even more so than in Cynodictis lacustris and Morphotype B. The plantar tubercle does not form a distally directed tip as seen in Cynodictis lacustris .

Distal view

The plantar tubercle is ventrally broad. The edge separating the plantar tubercule and the cuboid facet is more visible than in Cynodictis lacustris .

Proximal view

The proximal part of the tuber calcanei has a sub-spherical surface. The groove is slightly more pronounced than in Cynodictis lacustris .

Figures

FIG. 4. — Calcanei of undetermined amphicyonids from the Quercy (France; Priabonian-Chattian, MP18-MP30): A-E, Morphotype A, MNHN.F.Qu9845, left calcaneus (reversed views): A, dorsal view; B, lateral view; C, medial view; D, distal view; E, proximal view; F-J, Morphotype B, KUL.PLV1542_28, left calcaneus (reversed views); F, dorsal view; G, lateral view; H, medial view; I, distal view; J, proximal view; K-O, Morphotype C, KUL.PLV1542_29, left calcaneus (reversed views): K, dorsal view; L, lateral view;M, medial view; N, distal view; O, proximal view. Abbreviations:cf, cuboid facet; ef, ectal facet; lpt, lateral process of tuber; mpt, medial process of tuber; pp, peroneal process; plt, plantar tubercle; ptg, tendinous plantar groove; sg, sagittal groove; sf, sustentacular facet; st, sustentaculum tali; tc, tuber calcanei. Scale bar: 1 cm.