An odder chalicothere, Anisodon macedonicus, enters the LRT

Sorry, still no pix possible due to tech issues,
so please click the links, which will take you to the pertinent ReptileEvolution.com webpages.

Anisodon macedonicus
(Lartet 1851) preserves a rostrum much shorter than mandible. According to Wikipedia, “Anisodon is an extinct genus of chalicothere that lived in Europe during the late Miocene. It stood at about 150cm and weighed around 600kg. The animal’s clawed forelimbs would have allowed it to pull down tree branches in order to browse, as well as deter Miocene predators such as bear-dogs and saber-toothed cats.”

Traditionally,
chalicotheres (members of the clade Ancylopoda) are considered related to extinct brontotheres, as well as to modern day horses, rhinoceroses, and tapirs.

This appears to be due to dental similarities and taxon exclusion.

Here
in The large reptile tree chalicotheres nested not too far from brontotheres but farther from horses, rhinos and tapirs. In the LRT chalicotheres nest within the Phenacodus clade, between Litolophus and Anthracobune + Cambaytherium, basal to astrapotheres, which are basal to elephants.

New World brontotheres are likewise not related to extant perissodactyls, but nest closer to the more similar Arsinoitherium found in Old World Egyptian deposits in the Coryphodon clade sister to/preceding the Phenacodus clade.

Phenacodus and elephants had/have five fingers and toes.
Chalicotheres had three. In Phenacodus the medial and lateral fingers and toes were smaller, shorter and likely not weight-bearing. This readily evolved to the three-toed morphology in chalicotheres (as in three-toed horses) on one branch… and to graviportal elephants and astrapotheres on the other branch with larger weight-bearing medial and lateral digits, supported by extensive padding.

If you ever wondered about the claim
that some chalicotheres walked on their knuckles, unlike all other tetrapods – other than the great apes, there was little more than this in the literature: Gorilla proportions = knuckle walking. Furthermore, according to Wikipedia/Chalicotheriidae, “They could not retract the huge front claws, and knuckle-walked on their forelimbs.”

The article also compared chalicotheres with ground sloths and giant pandas.

Coombs 1989 wrote,
“The Chalicotherioidea, one of the most unusual perissodactyl groups., is most simply defined on the presence of clawed phalanges.”

Nowadays paleontologists define clades by their last common ancestors, no matter what their characters are included or excluded. In other words, Coombs described chalicotheres. She did not define them.

Coombs 1989 reported
“clearly perissodactyl dentitions” without considering convergence.

Remember: odontocetes have pelycosaur-like dentitions by convergence or, more probably, reversal – and they are clearly not pelycosaurs. They are derived ophiacodonts in the LRT. Plus, toothless taxa unrelated to one another frequent the LRT.

Don’t ‘Pull a Larry Martin’ by judging a clade by its teeth alone. Consider ALL (or at least several hundred) character traits in order to make room for possible convergence.

College textbooks still consider chalicotheres to be perissodactyls. This needs to change by testing with the addition of taxa, as in the LRT.

It’s rare to find a chalicothere with intact premaxillae
because chalicotheres those rostral bones are gracile, often toothless, boomerang shaped and don’t connect medially. In other words the premaxillae are more like splints of indeterminate bone than like a typical toothy premaxilla.

In Anisodon grande tiny, nearly granular teeth are present. The procumbent lower incisors are retained in many if not all chalicotheres.

Coombs dismisses the earlier hypothesis
that some chalicotheres were diggers in search of edible roots, reporting that clade members had few force-increasing modifications of the forelimb and their low-crowned teeth were poorly suited to a fibrous, gritty diet. Rather chalicotheres were leaf eaters, like giant ground sloths, and bipedal browsers, where the long foreclaws would have been used in similar fashion.

Hope this helps.

References
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.
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.
Bai B, Wang Y-Q and Meng J 2010. Early Eocene chalicothere Litolophus with hoof-like unguals. Journal of Vertebrate Paleontology 31(6):1387-1391.
Colbert EH 1934. Chalicotheres from Mongolia and China in the American Museum. Bulletin of the American Museum of Natural History 67: 353–387.
Coombs MC 1989. Chalicothere interrelations. The Evolution of Perissodactyls, D. R. Prothero and R. M. Schoch, eds.Publisher: Clarendon Press/Oxford University Press.
Cope ED 1882. Paleontological Bulletin 34:187.
Cope ED 1882a. Contributions to the history of the Vertebrata of the lower Eocene of Wyoming and New Mexico, made during 1881. Proceedings of the American Philosophical Society: 139-197.
Cope ED 1882e. Note on Eocene Mammalia. American Naturalist 16:522.
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).
Koufos GD 2012. New material of Chalicotheriidae (Perissodactyla, Mammalia) from the Late Miocene of Axios Valley, Macedonia (Greece) with the description of a new species. Annales de Paléontologie 98(3): 203-224.
Lartet É 1851. Notice sur la colline de Sansan. Extrait de l’Annuaire du Département du Gers, année 1851. Auch: J.-A. Portes.
Lydekker R 1899. Part 3. Containing the Order Ungulata, Suborders Perissodactyla, Toxodontia, Condylarthra, and Amblypoda. Catalogue of the Fossil Mammalia in the British Museum (Natural History). p. 162.
Marsh OC 1877. Notice of some new vertebrate fossils. American Journal of Arts and Sciences 14:249-256.
Radinsky LB 1964. Notes on Eocene and Oligocene fossil localities in Inner Mongolia.
American Museum Novitates 2180: 1–11.
Thewissen JGM 1990. Evolution of Paleocene and Eocene phenacodontidae (Mammalia, Condylarthra). University of Michigan Papers on Paleontology 29:1-107.

wiki/Chalicotherium
wiki/Moropus
wik/Anisodon
wiki/Ancylopoda
wiki/Chalicotheriidae

Source: https://pterosaurheresies.wordpress.com/2026/02/19/an-odder-chalicothere-anisodon-macedonicus-enters-the-lrt/