In a 2010 publication in the Zoological Journal of the Linnean Society, two new species of broad-nosed bats are described for the very first time. Both bats hail from Andean South America. Interestingly, both had been collected decades earlier by expeditions from the Field Museum of Natural History (to Peru, led by MacArthur Curator Bruce Patterson) and the National Museum of Natural History (to Venezuela, led by Curator Alfred Gardner). Unrecognized as new species, both series had been identified as the suppposedly widespread species Platyrrhinus helleri and stored in the research collections. It was not until Paúl Velazco, then a graduate student-in-residence at the Field Museum and now a post-doctoral associate of the American Museum of Natural History, began studying them that their differences were recognized.
Paúl Velazco in Moyobamba, Perú, May 2007.
This discovery, made two decades after the specimens were collected, is not really unsual. Rather, it has become the rule in systematic mammalogy and other disciplines. It serves as a compelling example of the value of large, encyclopedic reference collections like those at the Field Museum and the Smithsonian. These collections (and others like them) harbor examples of many species and include multiple individuals of each, documenting individual, seasonal, and geographic variation. Such valuable resources attract researchers from around the world. Discrimination of closely related forms often requires side-by-side comparisons that are only possible in these major collections. It is no mistake that these collections have become the world's greatest laboratories for the study of mammalian evolution.
Platyrrhinus masu Velazco 2005 (photo by B.D. Patterson)
Paúl's doctoral studies at the University of Illinois at Chicago have transformed our understanding of the diversity of these bats. Prior to his 2005 monograph in Fieldiana: Zoology, 10 species of Platyrrhinus were recognized. With the descriptions of Platyrrhinus angustirostris and Platyrrhinus fusciventris in 2010, the number of species known has doubled, to 20!! All live in the forests of Central and South America. Phylogenetic analyses by Paúl and Bruce (in the journal Molecular Phylogenetics and Evolution) show that the species belong to four different lineages. Although three of these clades are restricted to the lowlands, and the group evidently originated there, most of the species actually belong to the Andean clade. Molecular data indicates that there has been a recent burst of species-formation in the tropical Andes, where as many as 6 species of broad-nosed bats coexist along a single slope. Studies on this and other groups are on-going.
Velazco, P.M. 2005. Systematics and phylogenetic relationships of the broad-nosed bats, Genus Platyrrhinus (Chiroptera, Phyllostomidae). Fieldiana: Zoology, new series 105:iv + 1-53. pdf (1.4 Mb)Velazco, P.M. & B.D. Patterson. 2008. Phylogenetics and biogeography of the broad-nosed bats, Genus Platyrrhinus (Chiroptera: Phyllostomidae). Molecular Phylogenetics and Evolution 49:749-759. pdf (1.3 Mb)
Velazco, P.M., A.L. Gardner & B.D. Patterson. 2010. Systematics of the Platyrrhinus helleri complex (Chiroptera: Phyllostomidae), with descriptions of two new species. Zoological Journal of the Linnean Society 159:785-812. pdf (1.49 Mb)