Paramylodon, BROWN, 1903

Mcafee, Robert K., 2009, Reassessment of the cranial characters of Glossotherium and Paramylodon (Mammalia: Xenarthra: Mylodontidae), Zoological Journal of the Linnean Society 155 (4), pp. 885-903 : 889

GENUS PARAMYLODON BROWN, 1903

Type species: Paramylodon harlani ( Owen, 1840; Brown, 1903) Kraglievich, 1928

Synonymy: For a more complete synonymy list, see McDonald, 1995:

Mylodon harlani Owen, 1840

Paramylodon nebrascensis Brown, 1903

Mylodon garmani Allen, 1913

Revised diagnosis

This North American mylodontid is distinguished from its closest South American relatives, Mylodon and Glossotherium , by the following characters:

Skull: Dental formula varied with the loss of C1: 5/5, 4/5, or 5/4; C1 length along long axis of tooth-row less than 20 mm; M1 rectangular in shape, longer than wide; M2 triangular in section with a more prominent lingual groove, forming distinct posteriorly projecting lobe; M4 bilobate with posterior lobe wider than anterior lobe, and not as anteroposteriorly compressed as in Glossotherium ; molariform tooth-row accounts for more than 80 per cent of total tooth-row length; palatine length posterior to M4 greater than 30 mm; ratio of palate length posterior to M4 versus total maxillary–palatine length greater than 0.15; skull relatively flat in lateral view; posterior skull height nearly equal to height at level of postorbital processes; rostrum narrows posteriorly toward postorbital processes, and widens thereafter to back of skull; width of nasal cavity nearly equal to height; ratio of lacrimal to postorbital width nearly 1: 1; pterygoid sinuses weakly inflated and widely spaced; parasagittal crest narrow and temporal fossa well developed and rugose.

Mandible: Longer than Glossotherium and condyle is higher in proportion to coronoid process; ascending process of coronoid is straighter in its upward slope; predental spout narrow and more rounded anteriorly with little lateral flare.

Distribution: Specimens are known from multiple localities across the southern USA, with the most northerly occurrence in Washington, and are also found in parts of Mexico, making them restrict- ed to North America ( Stock, 1925; Villafranca & Carranza Castañeda, 1981; McDonald, 1995; Carranza Castañeda & Miller, 2004). Major localities are California (Rancho La Brea), Idaho (American Falls), and Florida (Haile and Ingleside). Temporally, specimens are known from the late Blancan to late Rancholabrean deposits (late Pliocene–late Pleistocene).

Referred specimens: See Appendix.