Diadiaphorus

Diadiaphorus is an extinct genus of litoptern mammal from the Miocene of Argentina (Ituzaingó, Pinturas, Chiquimil and Santa Cruz Formations) and Bolivia (Nazareno Formation), South America.

Diadiaphorus Temporal range: Early-Late Miocene (Santacrucian-Huayquerian) ~17.5–6.8 Ma PreꞒ Ꞓ O S D C P T J K Pg N
D. majusculus skull. Collected from Santa Cruz, Patagonia, Argentina.
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	†Litopterna
Family:	†Proterotheriidae
Subfamily:	†Proterotheriinae
Genus:	†Diadiaphorus Ameghino, 1887
Type species
†Diadiaphorus majusculus Ameghino, 1887
Species
D. caniadensis D. majusculus Ameghino, 1887 D. paranensis D. sanctaecrucis D. velox
Synonyms
Genus synonymy Bunodontherium Mercerat, 1891 D. majusculus Bunodontherium majusculum Mercerat, 1891 Diadiaphorus diplinthus Ameghino, 1894 Diadiaphorus robustus Ameghino, 1894 Diadiaphorus coelops Ameghino, 1904

Description

Size comparison between a human and D. majusculus.

Diadiaphorus closely resembled a horse, but was only around 1.2 metres (3.9 ft) in body length with a weight 70 kilograms (150 lb), similar to a modern sheep.^[1]

It had three toes, only one of which touched the ground. This toe had a large hoof; the two outer toes were rudimentary, much like those of early horses such as Merychippus. Unlike horses, however, Diadiaphorus lacked fused limb bones. Its skull was short and had a relatively large brain cavity. Judging from its low molars, Diadiaphorus ate soft vegetation, such as leaves.^[2]

1901 skeletal illustration of D. majusculus, mostly based on bones from two separate individuals.

1913 illustration of D. majusculus by Charles R. Knight.