Fossil Tapirs from the Pleistocene of Venezuala.

Tapirs are large tropical, forest dwelling, herbivorous mammals related to Horses and Rhinoceroses. They have an unusual distribution, being found in South and Central America, as well as in Southeast Asia. The oldest known Tapirs in the fossil record lived in North America during the early Eocene, around 55.4 million years ago. These early Tapirs are thought to have been essentially similar to modern Tapirs, though they probably lacked the small fleshy trunk that Tapirs have today. 

In a paper published in the journal Acta Palaeontologica Polonica on 25 July 2011, Elizete Holanda of the Programa de Pós−Graduação em Geociências at the Universidade Federal do Rio Grande do Sul and the Setor de Paleontologia at the Museu de Cięncias Naturais at the Fundação Zoobotânica do Rio Grande do Sul, and Ascanio Rincón of the Lab. Biología de Organismos Centro de Ecología at the Instituto Venezolano de Investigaciones Científicas, describe two partial fossil Tapirs from the Pleistocene of Venezuala.

The first fossil described comes from the El Breal de Orocual tar pits near Maturin City in Monagas State in the northwest of the country. Tar pits are essentially oil deposits identical to those worked by oil drills in other parts of the world, but exposed at the surface. When oil deposits are exposed in this way the lighter fractions (crude oil is made up of a mixture of different oils, known as 'fractions' due to the process used to separate them, fractional distillation) such as petroleum evaporate off, leaving the heavier fractions, known as tar, or asphalt, behind. These form oily pools in which animals can become trapped. The El Breal de Orocual pits have previously produced 24 different Mammal taxa, and are currently thought to be Plio-Pleistocene in age.

The specimen comprises an incomplete right maxilla and mandible (upper and lower jaw bones). These are on the slender side compared to modern Tapirs, but this is a variable trait within known species and cannot for this reason be considered diagnostic. For this reason the specimen is assigned to the modern genus Tapirus, but not classified to species level. 

Tapirus sp., El Breal de Orocual, Plio−Pleistocene. (A) Right maxilla in lateral (A1) and occlusal (A2) views. (B) Mandible in labial (B1) and occlusal (B2) views. Scale bars are 30 mm. Holanda & Rincón (2011).

If the Plio-Pleistocene data currently assigned to the El Breal de Orocual tar pits is correct (they were previously thought to be younger), then this specimen will represent the oldest known Tapir from South America. Tapirs are thought to have originated in North America in the Late Eocene; the oldest known fossils are North American and of early Miocene age, and Tapirs are Perissodactyls, related to Horses and Rhinoceroses that are also thought to have originated in the Eocene of North America. It has been suggested that Tapirs could have reached South America as early as the Late Miocene, but it is more likely that they arrived during the Great American Biotic Interchange, when the formation of the modern Isthmus of Panama allowed animals to migrate between North and South America from the Pliocene onwards.

The second specimen is from Zumbador Cave in eastern Falcón State, where a rich collection of Late Pleistocene bones has been found within a cave set it limestone of the Middle Miocene Capadare Formation, apparently having been carried there by the action of a river. This specimen is assigned to the modern species Tapirus terrestris, and comprises a partial skull, and incomplete left dentary (jawbone), an incomplete thoracic (back) vertebrae, an incomplete left humerus and femur (foreleg bones), a right astragalus (ankle bone) and part of the right pelvis.

 

Tapirus terrestris, Zumbador Cave, Pleistocene. (A) Incomplete skull in lateral (A1), posterior (A2), and dorsal (A3) views. (B) Left dentary in lingual view; a, height of the sagittal crest. Holanda & Rincón (2011).

Tapirus terrestris, Zumbador Cave, Pleistocene. (A) Thoracic vertebra in right lateral view. (B) Left humerus in posterior view. (C) Left radius in anterior view. (D) Incomplete right pelvis in lateral view. (E) Left femur in anterior view. (F) Right astragalus in dorsal view. Scale bars 30 mm. Holanda & Rincón (2011).

While a Late Pleistocene fossil of a modern species is not surprising, this represents the first known fossil of Tapirus terrestris. It is also outside the current range of the species, which is known from modern Venezuela, but largely south of the Orinoco.

The localities where the Venezuelan Tapir fossils were found. Holanda & Rincón (2011).

See also…

 Rhinoceros teeth from the Early Miocene of Gansu Province, China.

 A new species of Rhinoceros from the Late Miocene of northeastern Thailand.

 Three new species of Tapir from the Early Eocene of Pakistan.

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Signs of scavenging on a Pliocene Argentinean Glyptodont.

Glyptondonts were large, heavily armored mammals related to Armadillos that evolved first appeared in South America in the Miocene, spread to North America in the Pliocene and became extinct at about the same time as the earliest humans entered the Americas (this is almost certainly not a coincidence). The largest members of the group are thought to have weighed over a tonne and exceeded 3 m in length.

In a paper published in the journal Palaeontologia Electronica on 23 May 2013, a team of scientists led by Martín de los Reyes of the Facultad de Ciencias Naturales y Museo de La Plata describe a Glyptodont specimen from the late Pliocene of the Pampean region of Argentina. This is the first Glyptodont showing signs of predation from South America (several are known from North America, mostly associated with archaeological, i.e. human, sites), and is from an early stage in the Great American Interchange, when many of the large Marsupial predators that had dominated earlier South American faunas had disappeared, but before the arrival of Placental Carnivore groups such as Cats, Dogs and Bears that dominate modern faunas.

The Glyptodont specimen is referred to the species Eosclerocalyptus lineatus. It is buried on its side in fine-grained fluvial sediments, but with the hemimandible, ribs and vertebrae outside the dorsal carapace, suggesting disturbance of the corpse by a predator or scavenger.

One of the extracted bones, a vertebrae has a distinct bite-mark, which de los Reyes et al. interpret as closely matching the dentition of Capalmalania altifrontis, a large member of the Racoon Family known to have been present in the area at the time when the Glyptodont lived. While Capalmalania altifrontis had a (muscle supporting) sagittal crest and short snout similar to that of a Bear or Hyena, it is unlikely to have been able to actively predate the much larger Glyptodont, leading de los Reyes et al. to suggest this was the result of scavenging activity rather than predation.

(1) Rib of Eosclerocalyptus lineatus showing a row of pits interpreted as a bite mark. (2) The dentition of the snout of Capalmalania altifrontis. De los Reyes et al. (2013).

Two different views of a combined image of the rostrum of Chapalmalania altifrontis 'biting' the posterior vertebrae of Eosclerocalyptus lineatus. Scale bar is 10 mm. De los Reyes et al. (2013).

Reconstruction of the scene of consumption. Luz Irrazábal in de los Reyes et al. (2013).

See also A Giant Camel from the mid-Pliocene of Ellesmere Island in the Canadian Arctic, New Caviomorph Rodents from the Early Oligocene Tinguiririca Fauna of the Andean Main Range of central Chile, Three new species of Tapir from the Early Eocene of Pakistan, What killed the Australian Thylacine and New species of Bat discovered in Vietnam.

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