A new genus and species of vespertilionid bat from the Indomalayan Region

Increased genome size is caused by heterochromatin addition in two non-related bat species, Hesperoptenus doriae and Philetor brachypterus (Vespertilionidae, Chiroptera, Mammalia)

The average genome size (GS) of bats, which are the only mammals capable of powered flight, is approximately 18% smaller than that of closely related mammalian orders. The low nuclear DNA content of Chiroptera is comparable to that of birds, which are also characterized by a high metabolic rate. Only a few chiropteran taxa possess notable amounts of constitutive heterochromatin. Here, we studied the karyotypes of two non-related vesper bat species with unusually high amounts of constitutive heterochromatin: Hesperoptenus doriae and Philetor brachypterus. Conventional staining methods and whole-chromosome painting with probes derived from Myotis myotis (2n = 44), showing a karyotype close to that of the presumed ancestor of Vespertilionidae, revealed Robertsonian fusions as the main type of rearrangement leading to the exceptionally reduced diploid chromosome number of 2n = 26 in both species. Moreover, both karyotypes are characterized by large blocks of pericentromeric heterochromatin composed of CMA-positive and DA-DAPI-positive segments. In H. doriae, the heterochromatin accumulation has resulted in a genome size of 3.22 pg (1C), which is 40% greater than the mean genome size for the family. For P. brachypterus, a genome size of 2.94 pg was determined, representing an increase of about 28%. Most notably, in H. doriae, the presence of additional constitutive heterochromatin correlates with an extended mitotic cell cycle duration in vitro. A reduction in diploid chromosome number to 30 or lower is discussed as a possible cause of the accumulation of pericentromeric heterochromatin in Vespertilionidae.

A new genus of vespertilionid bat: the end of a long journey for Joffre's Pipistrelle (Chiroptera: Vespertilionidae)

Knowledge as to the taxonomic status of enigmatic bat species often is hindered by limited availability of specimens. This is particularly true for aerial-hawking bats that are difficult to catch. One such species, "Hypsugo" joffrei, was originally described in Nyctalus due to its long and slender wings, but subsequently transferred to Pipistrellus, and most recently to Hypsugo, on the basis of morphology. Analysis of newly available material, which more than doubles the known specimens of this taxon, demonstrates that it is morphologically and genetically distinct from all other bat genera. We accordingly describe it as belonging to a new, monotypic genus. We provide a detailed description of its external and craniodental traits, measurements, and assessment of genetic relationships, including barcode sequences to facilitate its rapid identification in future. The new genus belongs to a group that includes the recently described Cassistrellus, as well as Tylonycteris, and its closest relative, Philetor. We also describe the echolocation calls emitted by members of the taxon in different situations, which may facilitate finding them in previously unsampled locations. Based on the new data, the species occurs from Nepal to North Vietnam and China, which suggests that it could be more widespread than previously thought.

Unusual Pipistrelle: Taxonomic Position of the Malayan Noctule (Pipistrellus stenopterus; Vespertilionidae; Chiroptera)

Sergei V. Kruskop, Evgeniya N. Solovyeva, and Anna D. Kaznadzey (2018) Despite huge progress in the systematics of bats and, in particular, of the Vespertilionidae family in latest years, the taxonomic position of a number of remarkable bat species has been uncertain until now, partly because of limits in acceptable comparative material. Researchers have previously placed the Malayan noctule, Pipistrellus stenopterus, into Nyctalus, because of similar body shape and proportions, or into Pipistrellus, based on karyological analysis. This study reassesses Pipistrellus stenopterus using available collection material and compares it to various members of Nyctalus and Pipistrellus, as well as with some other related and similar genera, based on respective morphological and molecular genetic features. This species demonstrates vast morphological peculiarities compared to other Pipistrellus-like bats. Nonetheless, both mitochondrial and nuclear genetic markers unequivocally place it close to other Asian pipistrelles, most probably in a sister position to the "javanicus" species group. We propose establishing P. stenopterus as a separate subgenus, Alionoctula. Our results also confirm that Pipistrellus is paraphyletic in its current state, and we suggest that further studies explore its internal taxonomy and limits.

Predicting Extinction Risk for Data Deficient Bats

Conservation biology aims to identify species most at risk of extinction and to understand factors that forecast species vulnerability. The International Union for Conservation of Nature (IUCN) Red List is a leading source for extinction risk data of species globally, however, many potentially at risk species are not assessed by the IUCN owing to inadequate data. Of the approximately 1150 bat species (Chiroptera) recognized by the IUCN, 17 percent are categorized as Data Deficient. Here, we show that large trait databases in combination with a comprehensive phylogeny can identify which traits are important for assessing extinction risk in bats. Using phylogenetic logistic regressions, we show that geographic range and island endemism are the strongest correlates of binary extinction risk. We also show that simulations using two models that trade-off between data complexity and data coverage provide similar estimates of extinction risk for species that have received a Red List assessment. We then use our model parameters to provide quantitative predictions of extinction risk for 60 species that have not received risk assessments by the IUCN. Our model suggests that at least 20 bat species should be treated as threatened by extinction. In combination with expert knowledge, our results can be used as a quick, first-pass prioritization for conservation action.