First fossil record of Chiroptera (Phyllostomidae) from Uruguay (Plio-Pleistocene): a giant desmodontine

UBILLA, M. ; GAUDIOSO P. J.; PEREA, D.

Congreso; 5th International Paleontological Congress; 2018

The oldest remains of bats in South America (SA) are Eocene in age. The colonization of thiscontinent by this clade occurred in several dispersal events. Early diversification and subsequent dispersalmodelled its diversity in SA. Fossil remains are known from different sites and geological ages of SA (v.g.Brazil, Perú, Colombia, Venezuela, Argentina). Herein it is provided the first record of bats from Uruguay,represented by a complete right humerus (FCDPV-545), housed in the Paleontological Collection, Facultadde Ciencias, Montevideo. It comes from the Raigón Formation, which outcrops in the southwestern area ofUruguay. It has a fluvio-deltaic to fluvial origin, encompassing massive green silty-clayey beds intercalatedwith fine to mediumgrain sandy levels with parallel and cross-bedding stratification. At the top, paleosoilsdevelop. The mammalian content suggests a Pliocene-middle Pleistocene age. OSL ages of 373 and 218 kyrsfor the top of the sequence indicate a middle Pleistocene age. It yields terrestrial mammals, includingmedium to large ground-sloths, glyptodonts, large notoungulates and rodents (dinomyids), accompanied bylarge phorusrhacids and large aninghids. The studied humerus belongs to a giant bat referred to thevampire desmodontine group (Phyllostomidae). It was compared with the giant vampire Desmodusdraculae (Pleistocene/Holocene of Venezuela, Brazil and Argentina), D. archaeodaptes (late Pliocene/earlyPleistocene of NA), D. stocki (late Pleistocene of NA and Mexico), and the extant D. rotundus, and Diaemusyoungi desmodontine taxa. The humerus from Uruguay is similar in size to D. draculae, both clearly largestthan D. rotundus, D. archaeodaptes, Diaemus youngi and Diphylla ecaudata; is slightly longer than D. stockibut with a clearly wider distal transverse length. Qualitative morphological comparison substantiates theidentification of the material into the desmodontine group. Its overall morphology considering thecomparative set, more closely relates the material with the extinct D. draculae. Potential prey of this giantvampire bat may have included the giant dinomiyds, medium/large notoungulates and medium/largeground-sloths. Extant vampire bats are mostly distributed in warm to temperate areas of SA and Mexico.The record of this large desmodontine in the Raigón Formation suggests at least a temperate climate at thislatitude during the Plio-Pleistocene.