New bats in the tropical family Emballonuridae (Mammalia: Chiroptera) from the Oligocene and early Miocene of Florida

Abstract

Three new genera and four new species in the tropical bat family Emballonuridae (Mammalia: Chiroptera) are described from the Oligocene and early Miocene of peninsular Florida. These are: a new genus Oligopteryx and two new species, O. floridanus and O. hamaxitos, from the late Oligocene (early Arikareean) Brooksville 2 Local Fauna in Hernando County, with referred specimens of each species from the early Oligocene (Whitneyan) I-75 Local Fauna in Alachua County; a new genus and species, Karstopteryx gunnelli, from the latest Oligocene (late Arikareean) Buda Local Fauna in Alachua County; and a new genus and species, Floridopteryx poyeri, from the early Miocene (early Hemingfordian) Thomas Farm Local Fauna in Gilchrist County. Characters that distinguish Oligopteryx from other emballonurid genera are: M1 with a much reduced parastylar region and a large talon with a triangular posterolingual extension; M1 and M2 with a prominent hypocone separated from the protocone by a deep, V-shaped notch in the postprotocrista, and deeply concave talon basin; small, single-rooted p3; m1 and m2 with the trigonid narrower and shorter than the talonid, the paraconid and metaconid located close together along the lingual margin, and the entocristid blade-like, V-shaped, and oriented labially. O. hamaxitos is distinguished from O. floridanus by its smaller size and well-developed paraloph and metaloph on M1 and M2. Karstopteryx gunnelli is separated from the two species of Oligopteryx by the prominent parastyle, anteriorly oriented preparacrista, and rounded talon. Floridopteryx poyeri is characterized by: M1 with a highly reduced parastylar region but with a well-developed parastyle, short preparacrista, small hypocone not separated from the protocone by a notch in the postprotocrista, and a squarish talon; m1/m2 with the talonid much broader than the trigonid, trigonid compressed, shorter than talonid, and with the paraconid and metaconid close together along the lingual margin, large hypoconulid, and anterior root flattened and compressed anteroposteriorly (m1 only). Oligopteryx and Karstopteryx are considered members of the subfamily Emballonurinae based on the reduced parastylar region of the M1 but are left unassigned at the tribal level. Oligopteryx differs from all living emballonurids in the presence of a p3. Floridopteryx has a reduced parastylar region on M1 and is also considered an emballonurine, but can be separated from Oligopteryx by the presence of a prominent parastyle and lack of a p3. Floridopteryx is placed in the monophyletic New World emballonurine tribe Diclidurini. Taphonomy indicates Oligopteryx was a colonial cave dweller, whereas Floridopteryx more likely roosted in trees, as do most living Neotropical emballonurids. A change from a tropical or subtropical climate in Florida in the Oligocene and early Miocene to a warm temperate climate from the middle Miocene to the present is reflected in the disappearance of emballonurids from Florida after the early Miocene. Molecular studies indicate the Emballonuridae dispersed from Africa to South America in the Oligocene, despite the oldest Western Hemisphere record of this family from the early Oligocene (~30 Ma) of Florida (Oligopteryx). We hypothesize emballonurids may have reached North America from Eurasia in the Eocene using an overland route and then dispersed overwater to the then-island continent of South America, with the oldest South American record of that family from the late Oligocene (~25 Ma) of Peru.