Procavia, Phosphatherium, Grangeria, Diadiaphorus and Litolophus

Procavia capensis (Pallas 1756, 50cm) is the living rock hyrax and a living relative of Elephas and Dusisiren. Superficially it resembled a guinea pig. It inhabits rock crevices and lives in groups of 10-80 with some acting as sentries to sound the alarm at the sight of predators. They use at least 21 vocal signals. Distinct from its relatives, Procavia is thickly furred. Note the tusk-like incisors with deep roots. The soles of the feet are heavily padded. The testes are held within the abdomen. It rests most of the time, often basking in the equatorial sun.

Diadiaphorus and Procavia skulls compared

Grangeria gobiensis (Zdansky 1930, Colbert 1934) is known from crushed materials of several individuals of various sizes. The incisors are large, as in Procavia. The manus and pes are transitional to derived chalicotheres. The generic name is shared with a plant. This taxon nests at the base of the hippo clade.

Litolophus gobiensis (Radinsky 1964b, Bai, Wang and Meng 2010, 2011; Early Eocene) is traditionally considered a basal chalicothere with a slender premaxilla that curves ventrally and a tall parietal. In the LRT this taxon is transitional from chalicotheres to the rest of the perissodactyls. The hooves were small and round, not large and sharp.

Diadiaphorus majusculus (Ameghino 1887; Hatcher and Scott 1910; Miocene, 10mya; 1.2 m long) was a horse-mimic with only one hoof contacting the substrate. This South American perissodctyl was a sister to the living hyrax, Procavia from Africa.

Thoatherium minusculum (Ameghino 1887, Hatcher 1901, 70cm long) is primitive for Liptoterna in the LRT, despite the highly derived single finger and toe. That means there is a more primitive three-toed version of Thaotherium waiting to be described. Dorcatherium is the outgroup taxon. Too few fingers and toe parts were preserved to count the digits.w

Phosphatherium and Ectocion ralstonensis

Phosphatherium escuillei (Gheerbrant, Sudre and Cappetta 1996; Late Paleocene; 10cm skull length) nests with the hyrax, Procavia.

Ameghino F 1887. Enumeracion sistematica de las especias de mamiferos fosiles coleccionados por Carlos Ameghino en los terrenos eocenos de la Patagonia austral. La Plata.

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 47(3):353–387.

Gheerbrant E, Sudre J and Cappetta H 1996. A Palaeocene proboscidean from Morocco. Nature. 383 (6595): 68–71.

Gheerbrant E 2009. Paleocene emergence of elephant relatives and the rapid radiation of African ungulates. Proc Natl Acad Sci USA. 106(26): 10717–10721.

Gheerbrant E et al. 2005. Nouvelles données sur Phosphatherium escuilliei (Mammalia, Proboscidea) de l’Éocène inférieur du Maroc, apports à la phylogénie des Proboscidea et des ongulés lophodontes. Geodiversitas 27 (2), 2005, pp. 239-333.

Hatcher JB 1901. Reports of the Princeton University Expeditions to Patagonia, 1896-1899. J. B. Hatcher in charge. Princeton, The University.

Hatcher JB and Scott WB 1910. Reports of the Princeton University Expeditions to Patagonia 7(1-3):

Pallas PS 1766. Miscellanea zoologica. AP van Cleef, La Haye, 224 pp.

Radinsky LB 1964b. Notes on Eocene and Oligocene fossil localities in Inner Mongolia.
American Museum Novitates 2180: 1–11.

Vautrin Q et al. (11 co-authors) 2020. New remains of Lophiaspis maurettei (Mammalia, Perissodactyla) from the Early Eocene of France and the implications for the origin of the Lophiodontidae. Journal of Vertebrate Paleontology. 40(6): e1878200.

Zdansky 0 1930. 'Die Alttertiaren Saugetiere Chinas nebst Stratigraphischen
Bemerkungen.' Pal. Sinica, Ser. C, VI, fas. II, pp. 62-72, Pls. Iv, figs. 9-16, v, figs. 1-20.

wiki/Procavia
wiki/Diadiaphorus
wiki/Litolophus
wiki/Thoatherium
wiki/Phosphatherium