Systematics and evolutionary history of the neotropical bats Pteronotus (Chiroptera: Mormoopidae)

Author(s)

Ana Carolina D'Oliveira Pavan

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto de Biociências (IBIOC/SB)
• Defense date: 2014-12-11

Examining board members

Gabriel Henrique Marroig Zambonato; Norberto Pedro Giannini; Diego Astúa de Moraes; Valéria da Cunha Tavares

• Advisor: Gabriel Henrique Marroig Zambonato

Abstract

A multidisciplinary approach integrating molecular systematics, morphometrics and quantitative genetics was used to investigate the evolutionary history of the genus Pteronotus (Chiroptera: Mormoopidae). This Neotropical bat group has received particular attention in the last decade for harboring a genetic diversity much higher than morphological variation and taxonomic diversity currently described. According to the last systematic review this genus has six species with 17 subspecies. However, recent studies reported high levels of genetic divergence among conspecific taxa, suggesting an underestimated diversity for the genus. To date, no work combining genetic evidences and morphometric variation from all taxonomic units currently recognized in this group was performed. Based on a comprehensive sampling including most of the geographic range and 19 from 20 nominal taxa recognized for the genus, I investigated the genetic and morphological variation and the phenotypic covariance patterns among skull characters of Pteronotus species. Additional investigations were made to propose date intervals for the main diversification events within the group, and possible evolutionary and biogeographic processes responsible for the number and distributional patterns of current species. The phylogenetic analyses, using five loci, corroborate previous results on the criptic diversity of the group, and suggest a high correspondence among the genetic lineages and the currently recognized subspecies. Discriminant analysis of 41 variables describing size and shape of cranial bones support the rising of these groups to the specific status. Therefore, we present an updated taxonomic arrangement composed by 18 species. The cranial integration pattern of the family Mormoopidae shows a relatively conserved structure, in accordance with previous results for other mammal groups, followed by low levels of overall magnitude of integration in the majority of species. Results suggest a highly modular skull for mormoopids, and a pattern of structural association among characters that cannot be explained by genetic drift alone in most part of phylogeny nodes. Data indicates that skulls of Mormoopidae should be very flexible in their evolutionary responses, and that natural selection acted together over different lines of variation in cranial structure during the group\'s diversification. Pteronotus arose in Miocene, around 17 million years ago, and the diversification events yielding to the main clades within the genus took place from 15 to 7 million years ago. The replicated pattern of geographic occupancy among different clades of Pteronotus suggest an essentially vicariant model of speciation, but dispersion is also required to explain the geographic range of some of the current lineages, as well as the estimated ancestral areas of some phylogeny nodes. Many of the species in the genus arose in the last three million years , when the American continent underwent some geographic reorganizations and severe climatic oscillations, while the intraspecific diversification events are very recent, having ocurred in the Late Pleistocene (AU)