The complex evolutionary history of big-eared horseshoe bats (Rhinolophus macrotis complex): insights from genetic, morphological and acoustic data

Keping Sun,Xuewen Wei,Aiqing Lin,Longru Jin,Jiang Feng,Rebecca T Kimball,Tinglei Jiang,Tong Liu

doi:10.1038/srep35417

Abstract

Palaeoclimatic oscillations and different landscapes frequently result in complex population-level structure or the evolution of cryptic species. Elucidating the potential mechanisms is vital to understanding speciation events. However, such complex evolutionary patterns have rarely been reported in bats. In China, the Rhinolophus macrotis complex contains a large form and a small form, suggesting the existence of a cryptic bat species. Our field surveys found these two sibling species have a continuous and widespread distribution with partial sympatry. However, their evolutionary history has received little attention. Here, we used extensive sampling, morphological and acoustic data, as well as different genetic markers to investigate their evolutionary history. Genetic analyses revealed discordance between the mitochondrial and nuclear data. Mitochondrial data identified three reciprocally monophyletic lineages: one representing all small forms from Southwest China, and the other two containing all large forms from Central and Southeast China, respectively. The large form showed paraphyly with respect to the small form. However, clustering analyses of microsatellite and Chd1 gene sequences support two divergent clusters separating the large form and the small form. Moreover, morphological and acoustic analyses were consistent with nuclear data. This unusual pattern in the R. macrotis complex might be accounted for by palaeoclimatic oscillations, shared ancestral polymorphism and/or interspecific hybridization.

Highlights

Bats represent over 20% of mammal species[12]
Based on our recent field surveys in China, we observed the species complex had a continuously and widespread distribution throughout Central and South China, and they frequently roost in colonies including both small and large forms (Fig. 1), which suggests that complex evolutionary processes might be occurring in the R. macrotis complex
For 79 individuals in the R. macrotis complex sampled from 14 localities across the entire Chinese range of the species, we found much variation in cytochrome b (Cytb) (1,140 bp) and control region (464 bp)

Summary

Introduction

Bats represent over 20% of mammal species[12]. documented cases of complex evolutionary histories involving paraphyly in this group are very rare[13,14,15,16,17]. In order to examine their evolutionary history and speciation, we used ten unlinked genetic markers, including mtDNA (Cytb and control region) and ncDNA (eight microsatellite loci and Chd[1] gene) to reconstruct the phylogeny of the big-eared horseshoe bat species complex from China. We combined this with morphological data (i.e. external measurements) and acoustic data (i.e. echolocation frequency). Our study aimed to (i) determine genetic lineages in this species complex; (ii) determine whether the mtDNA variation is congruent or conflicts with the nuclear and phenotypic data (i.e. morphological and acoustic measurements); (iii) if conflicting, evaluate potential mechanisms leading to patterns within this species complex; (iv) and, evaluate the effect of palaeoclimatic changes on this species complex

Methods

Results

Discussion

Conclusion