Chalicothere skulls to scale

Figure 1. Moropus elatus is a horse-sized chalicothere from the Miocene.

Figure 1. Moropus elatus is a horse-sized chalicothere from the Miocene. Note the large claws on the manus and smaller ones on the pes.

As we’ve seen before
there are several horse-like taxa in the mammal family tree. Known for over 150 years and worldwide in dispersal, the chalicotheres (Figs. 1-3) had claw-like hooves on an otherwise horse-like body and skull.

Figure. 2. Chalicothere skulls to scale. Lophiodon is an outgroup closer to tapirs.

Figure. 2. Chalicothere skulls to scale. Lophiodon is an outgroup closer to tapirs.

Because several taxa
in the large reptile tree have horse-like traits, the ability to split and lump these taxa is being taxed. Moreover, the outgroup for the chalicotheres has shifted with the addition of more closely related taxa.

Lophiodon
nests close to the base of the chalicotheres, close to tapirs and other extinct South American mammals.

Litolophus
(Fig. 2) is a basal chalicothere with round, hoof-like hooves. Basal taxa have four metacarpals. The fourth one is reduced on later taxa. What looks like a Pteranodon-like crest would have been layered with strong jaw muscles.

Tylocephalonyx
(Fig. 2) had a domed cranium, distinct from other chalicotheres.

Anisodon macedonicus 
(Fig. 2) had a short, primate-like face, distinct from other chalicotheres.

Anisodon grande
(Fig. 3) is another derived chalicothere with longer forelimbs, no tail and probably sat on its large buttocks while feeding.

Figure 3 Anisodon grande had longer forelimbs than hind limbs.

Figure 3 Anisodon grande had longer forelimbs than hind limbs.

More later
as the study proceeds…

References
Bai B, Wang Y-Q and Meng J 2010. New craniodental materials of Litolophus gobiensis (Perissodactyla, “Eomoropidae”) from Inner Mongolia, China, and phylogenetic analyses of Eocene chalicotheres. American Museum Novitates 3688: 27pp.
Colbert EH 1934. Chalicotheres from Mongolia and China in the American Museum. Bulletin of the American Museum of Natural History 67: 353–387.
de Blainville HMD 1849. Ostéographie ou description iconographique comparée du squelette et du système dentaire des Mammifères récents et fossiles – Genus Anoplotherium. 4 BB, Paris: J.B. Baillère, 66–70.
Kaup CC 1833. Description d’ossements fossiles de mammifère’s inconnus jusqu’ à-présent, qui se trouvent au Muséum grand-ducal de Darmstadt. Second cahier. – 1 – 31.Darmstadt (J.G.Heyer).
Lartet É 1851. Notice sur la colline de Sansan. Extrait de l’Annuaire du Département du Gers, année 1851. Auch: J.-A. Portes.
Marsh OC 1877. Notice of some new vertebrate fossils. American Journal of Arts and Sciences 14:249-256.

wiki/Chalicotherium
wiki/Litolophus
wiki /Moropus
wik/ Anisodon

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2 thoughts on “Chalicothere skulls to scale

  1. Anisodon grand”e” is correctly A. grandis, because a tooth is a he and not an it in Greek. Also, you disarticulated the poor beast’s shoulder, elbow (ouch!) and metacarpophalangeal joints; I even have to wonder if the “humerus” is the ulna and the “radius + ulna” the humerus in your reconstruction, where also most of the shoulder blade is missing.

  2. Unfortunately your preconceptions are guiding your comments. You can google Anisodon and you’ll find grandis is redirected to grande, no matter what your ‘because’ is. The forelimb: Take a look at other reconstructions and the in situ fossil. Most of the shoulder blade is probably missing — from the fossil too.

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