| Neolicaphrium | |
|---|---|
 | |
| Right hemimandible ofN. recens | |
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | †Litopterna |
| Family: | †Proterotheriidae |
| Subfamily: | †Proterotheriinae |
| Genus: | †Neolicaphrium Frenguelli 1921 |
| Type species | |
| †Neolicaphrium recens Frenguelli 1921 | |
| Species | |
Neolicaphrium is an extinctgenus ofungulatemammal belonging to the extinct orderLitopterna. This animal lived from the Late Pliocene (Chapadmalalan) to the Late Pleistocene (Lujanian) in southern South America, being the last survivor of the familyProterotheriidae.
The genus includes two species, the type speciesN. recens andN. major. The fossil found ofN. major, one jaw, come from theMiramar Formation in Chapadmalal,Argentina and correspond to theChapadmalalan mammal age of South America (4.0 to 3.0 million years ago, in the Pliocene).N. recens appeared in theEnsenadan age (1.2-0.8 million years ago) and the species survived until theLujanian age (800,000 to 11,000 years ago). Fossils of this species have been found in the Argentine provinces of the northeast, inCórdoba,Corrientes,Tezzanos Pinto Formation,Santa Fe andSantiago del Estero,[3] in the southern Brazilian state ofRio Grande do Sul and theSopas Formation of theSalto Department in Uruguay.[4]N. recens is known from a partial skull, partial jaws, teeth and bones of the ankle and the forefeet.[5] A fragmentary humerus, previously assigned to the doubtful species "Proterotherium berroi", could also be referred to this species.[6]
Neolicaphrium was a proterotherid of small (N. recens) to medium (N. major) size.N. recens, weighing about 37 kilograms was one third smaller thanN. major. In general terms,Neolicaphrium resembledThoatherium of theMiocene, one of the most famous proterotherids, by its relatively graceful build adapted to acursorial locomotion, although without presenting the extrememonodactyly that characterizesThoatherium, so that still retained its three fingers in each hand and foot. Similar to the smaller deer of today, such as thepudus, thepampas deer and themuntjac,Neolicaphrium was a browsing herbivore. The isotopic analysis of the fossils indicates thatNeolicaphrium fed mainly on fruits and to a lesser extent on terrestrial plants that grew at ground level, and that leaves were only a very limited part of their diet.[7]
The composition of the fauna of the Sopas Formation in Uruguay, where fossils ofN. recens from the late Pleistocene have been found,[8] indicates thatNeolicaphrium was a resident of savannahs and open tree forests. The rocks of the Sopas Formation were deposited in a gallery forest with rivers andNeolicaphrium lived there along with other mammals such as tapirs, thewhite-lipped peccary, the prehensile tail porcupineCoendou magnus, the capybara, the jaguar and the otter, species that characterize the tropical forest areas of South America.[9]
The genusNeolicaphrium was first described in 1921 by Frenguelli, based on incomplete remains found inArgentina. Thetype species,Neolicaphrium recens, is typical of Upper Pliocene - Upper Pleistocene deposits of Argentina,Uruguay andBrazil, while the speciesN. major was found in Pliocene soils of Argentina.
Neolicaphrium is the last of the proterotheres, a group of litoptern mammals with shapes similar toequids, particularly with regard to leg structure.Neolicaphrium, in any case, was not the most specialized proterothere.
Previously it was thought that the family Proterotheriidae became extinct during the Pliocene, as a consequence of the climatic changes that occurred in the transition to the Pleistocene, along with thepachyrukhinenotoungulates and theargyrolagid metatherians. The fossil record ofN. recens however, showed that this group survived until the late Pleistocene in forest areas, outside the typicalPampa regions of the Southern Cone that were predominant during the Quaternary ice ages; However, this idea was rejected until the 21st century, when the new fossil finds allowed to corroborate its presence in the Pleistocene. In the Sopas Formation have been found also fossils of several types of deer (Pampas deer and an extinct form).[10]Neolicaphrium therefore coexisted throughout the Pleistocene with ungulate mammals ofholarctic origin. Both competition with these animals, which reached South America during theGreat American Biotic Interchange, and the environmental changes occurring since the end of the Miocene, which led to the disappearance of forest areas, may have contributed the decline and extinction of proterotherids.[11]
