No abstract

In taxonomic accounts, three species of Myotis have been traditionally reported to occur on the island of Taiwan: Watase's bat (M. formosus watasei Kishida), the Formosan broad-muzzled bat (M. muricola latirostris Kishida) and the Formosan mouse-eared bat (M. adversus taiwanensis Linde). The discovery in 1997 of an unknown taxon not fitting to the description of any of these species encouraged us to re-examine more thoroughly the systematics and phylogeny of Myotis bats inhabiting Taiwan. We used a combination of morphologic and molecular methods to aid the identification of the different taxa from this island and reconstruct their phylogenetic relationships. Multivariate analyses based on 17 craniodental characters of 105 specimens caught across Taiwan and further external characters allowed us to discriminate eight taxa of Myotinae co-occurring on this island. A subset of 80 specimens were further sequenced for the cytochrome b gene (1140 bp) and subjected to phylogenetic reconstructions including representative species from adjacent China and from all main lineages of the worldwide Myotis radiation. These molecular reconstructions showed that the Myotinae from Taiwan are phylogenetically diverse and are issued from several independent clades. The genetic results were completely congruent with the phenetic groupings based on craniodental and external morphology, as each of the eight Taiwanese taxa proved to be reciprocally monophyletic. Two unnamed taxa that did not fit into any of the known species were described as species new to science. Furthermore the taxon latirostris usually associated to the Asian M. muricola, was phylogenetically and morphologically distant from any other known Myotis and was assigned here to the fossil (Miocene) genus Submyotodon. Submyotodon latirostris, M. secundus sp. n. and M. soror sp. n. are endemic species from Taiwan, whereas the other five Myotis are more widespread and also found in the mainland. An identification key is provided to ease the discrimination of these Myotinae species in Taiwan and adjacent China.

Bats have been demonstrated to be natural reservoirs of severe acute respiratory syndrome coronavirus (SARS CoV) and Middle East respiratory syndrome (MERS) CoV. Faecal samples from 248 individuals of 20 bat species were tested for partial RNA-dependent RNA polymerase gene of CoV and 57 faecal samples from eight bat species were tested positive. The highest detection rate of 44% for Scotophilus kuhlii, followed by 30% for Rhinolophus monoceros. Significantly higher detection rates of coronaviral RNA were found in female bats and Scotophilus kuhlii roosting in palm trees. Phylogenetic analysis classified the positive samples into SARS-related (SARSr) CoV, Scotophilus bat CoV 512 close to those from China and Philippines, and Miniopterus bat CoV 1A-related lineages. Coronaviral RNA was also detected in bat guano from Scotophilus kuhlii and Myotis formosus flavus on the ground and had potential risk for human exposure. Diverse bat CoV with zoonotic potential could be introduced by migratory bats and maintained in the endemic bat population in Taiwan.

Laryngeally echolocating bats avoid self-deafening (forward masking) by separating pulse and echo either in time using low duty cycle (LDC) echolocation, or in frequency using high duty cycle (HDC) echolocation. HDC echolocators are specialized to detect fluttering targets in cluttered environments. HDC echolocation is found only in the families Rhinolophidae and Hipposideridae in the Old World and in the New World mormoopid, Pteronotus parnellii. Here we report that the hipposiderid Coelops frithii, ostensibly an HDC bat, consistently uses an LDC echolocation strategy whether roosting, flying, or approaching a fluttering target rotating at 50 to 80 Hz. We recorded the echolocation calls of free-flying C. frithii in the field in various situations, including presenting bats with a mechanical fluttering target. The echolocation calls of C. frithii consisted of an initial narrowband component (0.5±0.3 ms, 90.6±2.0 kHz) followed immediately by a frequency modulated (FM) sweep (194 to 113 kHz). This species emitted echolocation calls at duty cycles averaging 7.7±2.8% (n = 87 sequences). Coelops frithii approached fluttering targets more frequently than did LDC bats (C.frithii, approach frequency  = 40.4%, n = 80; Myotis spp., approach frequency  = 0%, n = 13), and at the same frequency as sympatrically feeding HDC species (Hipposideros armiger, approach rate  = 53.3%, n = 15; Rhinolophus monoceros, approach rate  = 56.7%, n = 97). We propose that the LDC echolocation strategy used by C. frithii is derived from HDC ancestors, that this species adjusts the harmonic contents of its echolocation calls, and that it may use both the narrowband component and the FM sweep of echolocations calls to detect fluttering targets.