Published July 16, 2020 | Version v1

Morphotype 3

  • 1. CR 2 P (CNRS, MNHN, Sorbonne Université), Département Origines et Évolution, Muséum national d'Histoire naturelle, case postale 38, 57 rue Cuvier, F- 75231 Paris cedex 05 (France)
  • 2. Evolution & Diversity Dynamics Lab, Université de Liège (ULiège), Quartier Agora, Bâtiment B 18, Allée du six août, 14, 4000 Liège (Belgium)
  • 3. KU Leuven, Department of Earth and Environmental Sciences, Celestijnenlaan 200 E, B- 3001 Leuven-Heverlee (Belgium)
  • 4. Directorate Earth and History of Life, Palaeobiosphere Evolution Research Unit, Royal Belgian Institute of Natural Sciences, Rue Vautier 29, B- 1000 Brussels (Belgium)

Description

Morphotype 3

(Fig. 3 K-O)

Dorsal view

The trochlea is weakly excavated. The medial and lateral lips are of different proximodistal length, the lateral being shorter than the medial. The proximal plantar tuberosity is very slightly broad. The neck is short. In two specimens (MNHN.F.Qu10042 and MNHN.F.Qu10367), the neck is slightly longer than in the others, but these two specimens do not differ enough to represent another morphotype. The head is broad and projected on the medial side. It has more pronounced edges on the lateral side than on the medial one and rises strongly on the medial edge of the neck, reaching the level of the most distal edge of the trochlea.

Ventral View

The medial and lateral edges of the ectal facet are curved (more on the medial than on the lateral edge). A foramen is visible at the proximal level. The sustentacular facet has a rhomboidal area. Its edges are marked. The facet is slightly convex except on its proximomedial extension, where it becomes concave. In two specimens (MNHN.F.Qu10042 and MNHN.F.Qu10367), the sustentacular facet is slightly less elongated and more proximally positioned on the body than in the others.

Lateral view

The edges of the fibular facet are relatively rounded, giving this facet a half-moon look, as in Morphotype 2. The ectal facet is sharply convex.

Distal view

The axis of elongation of the head is slightly inclined with respect to the mediolateral axis of the astragalus. The lateral process is only slightly broad.

Proximal view

The trochlear foramen is absent in some specimens and present in others. The proximoventral edge of the medial lip of the trochlea (trochlea tali proximalis) forms a small ventral point. The tendinous plantar groove is present but weakly excavated and is well inclined relative to the axis of the trochlea.

Notes

Published as part of 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, pp. 305-325 in Geodiversitas 42 (18) on page 314, DOI: 10.5252/geodiversitas2020v42a18, http://zenodo.org/record/3952805

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Linked records

Additional details

Biodiversity

Kingdom
Animalia
Phylum
Chordata
Order
Carnivora
Family
Amphicyonidae
Genus
Morphotype 3
Taxon rank
genus