Metacheiromys

Metacheiromys ("next to Cheiromys") is an extinct genus of mammal from the early to middle Eocene of what is now Wyoming.

Metacheiromys Temporal range: 50.3–46.2 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓ early to middle Eocene
Metacheiromys marshi skeleton.
Reconstruction of Metacheiromys marshi
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	†Palaeanodonta
Family:	†Metacheiromyidae
Subfamily:	†Metacheiromyinae
Genus:	†Metacheiromys Wortman, 1903
Type species
Metacheiromys marshi Wortman, 1903
Species
Metacheiromys dasypus Metacheiromys marshi
Synonyms
M. dasypus Metacheiromys osborni (Simpson, 1931)[1] M. marshi Metacheiromys tatusia (Osborn, 1904)

Metacheiromys was a small creature, and measured around 45 centimetres (18 in) long. It had long claws and a narrow head similar in shape to that of an armadillo or an anteater (though it was actually related to the modern pangolins). The shape of its claws suggests that it probably dug through the soil in search of food, most likely small invertebrates. Unlike modern anteaters or pangolins, it had powerful canine teeth, but only a very few cheek teeth, instead using horny pads in its mouth to crush its food.[2]

The generic name means "next to Cheiromys" because the scientist who saw the bones mistakenly thought that the animal was a primate with hands like those of the aye-aye (Daubentonia madagascariensis), one synonym being Cheiromys.

Metacheiromys and its relatives, including the enigmatic Ernanodon, constitute the order Palaeanodonta, thought to be the sister taxon of pangolins.[3]

Taxonomy

• Genus: †Metacheiromys
  • †Metacheiromys dasypus (Osborn, 1904)
  • †Metacheiromys marshi (Wortman, 1903)

Phylogenetic tree

The phylogenetic relationships of genus Metacheiromys is shown in the following cladogram:[4][5][3]

Pholidotamorpha	Pholidota (sensu stricto)    †Palaeanodonta    †Escavadodontidae      ?  †Amelotabes    ?  †Melaniella       †Epoicotheriidae    ?  †Arcticanodon     †Metacheiromyidae   †Propalaeanodontinae       †Mylanodon       †Brachianodon       †Palaeanodon      †Metacheiromys    †Metacheiromys dasypus     †Metacheiromys marshi    ?  †Metacheiromys sp. (CP 25J2)       †Ernanodonta         †Metacheiromyinae
(Pholidota sensu lato)

References

1. G. G. Simpson. (1931.) "Metacheiromys and the Edentata." Bulletin of the American Museum of Natural History 59(6)
2. Palmer, D., ed. (1999). The Marshall Illustrated Encyclopedia of Dinosaurs and Prehistoric Animals. London: Marshall Editions. p. 206. ISBN 1-84028-152-9.
3. Kondrashov, Peter; Agadjanian, Alexandre K. (2012). "A nearly complete skeleton of Ernanodon (Mammalia, Palaeanodonta) from Mongolia: morphofunctional analysis". Journal of Vertebrate Paleontology. 32 (5): 983–1001. doi:10.1080/02724634.2012.694319.
4. Kenneth D. Rose (2008). "9 - Palaeanodonta and Pholidota". doi:10.1017/CBO9780511541438.010. Cite journal requires |journal= (help)
5. Gaudin, Timothy (2009). "The Phylogeny of Living and Extinct Pangolins (Mammalia, Pholidota) and Associated Taxa: A Morphology Based Analysis" (PDF). Journal of Mammalian Evolution. Heidelberg, Germany: Springer Science+Business Media. 16 (4): 235–305. doi:10.1007/s10914-009-9119-9.