A new early Pleistocene tapir (Mammalia: Perissodactyla) from Florida, with a review of Blancan tapirs from the state

Abstract

Florida has the best late Blancan (early Pleistocene, 2.6–1.6 Ma) record of Tapirus in North America. The genus is currently known from 25 fossil localities of Blancan age, ranging through most of the peninsular region of the state. Three species are recognized from this time interval in Florida: the relatively large-sized Tapirus haysii Leidy; the moderate-sized Tapirus lundeliusi sp. nov.; and a much smaller, as yet unnamed species. Tapirus haysii was previously known from the early Irvingtonian (ca. 1.6 to 1.0 Ma) in Florida; the specimens reported here from seven localities extend its range into the Blancan, which is in accord with Blancan records from North Carolina (type locality) and the central United States. The Blancan finds of T. haysii in Florida are all relatively sparse, mostly consisting of one or two isolated teeth per locality. The unnamed small Blancan species of Tapirus is slightly better known: three jaw fragments each with a single tooth; four isolated teeth; a phalanx; and a navicular from a total of five different localities. It is significantly smaller than any extant species of Tapirus and all of those previously described from the  Pleistocene of North America. ‘Dwarf’ tapirs are known from the Hemphillian of the southeastern United States (e.g., Tapirus polkensis) and the late Miocene of Europe (e.g., Tapirus pannonicus), but this is thefirst case of their persistence into the Pleistocene. The small Blancan tapir is on average slightly larger than Tapirus polkensis, and is the same size as an undescribed species of Tapirus present in the late Hemphillian Palmetto Fauna of central Florida.

Tapirus lundeliusi sp. nov. is described on the basis of multiple skeletons from the Haile 7C and 7G localities of north-central Florida, and more limited samples from nine other Blancan sites. It apparently became extinct near the Blancan-Irvingtonian boundary, with its youngest confirmed record at the Inglis 1A locality. Tapirus lundeliusi is of moderate size for the genus, similar to extant Tapirus terrestris and Tapirus pinchaque, and the middle to late Pleistocene species Tapirus veroensis. It is significantly smaller than Tapirus haysii. The skull of T. lundeliusi differs from those of T. veroensis and T. haysii in retaining a number of primitive features, such as having a small maxillary flange, longer nasal bone, shorter lacrimal bone, and ontogenetically rapid fusion of interparietal to occipital. Derived features of T. lundeliusi include a reduced frontal shield and increased relative mandibular condyle height. Phylogenetic analysis places T. lundeliusi as the sister taxon of T. veroensis + T. haysii, and the clade formed by these three North American fossil species is formally designated as Tapirus (Helicotapirus) subgen. nov. Among other species of Tapirus, the extant T. bairdii and the late Neogene T. polkensis are most closely related to T. (Helicotapirus). They all share a large, triangular interparietal; broad, flat posterior lacrimal process; and extensive meatal fossa on the dorsal surface of the frontal and nasal bones.