No abstract

Recent historical and anthropogenic changes in the landscape causing habitat fragmentation can disrupt the connectivity of wild populations and pose a threat to the genetic diversity of multiple species. This study investigated the effect of habitat fragmentation on the structure and genetic diversity of the Mexican greater funnel-eared bat (Natalus mexicanus) throughout its distribution range in Mexico, whose natural habitat has decreased dramatically in recent years. Genetic structure and diversity were measured using the HVII hypervariable domain of the mitochondrial control region and ten nuclear microsatellite loci, to analyze historical and contemporary information, respectively. The mitochondrial and nuclear results pointed to a differential genetic structuring, derived mainly from philopatry in females. Our results also showed that genetic diversity was historically high and currently moderate; additionally, the contemporary gene flow between the groups observed was null. These findings confirm that the effects of habitat fragmentation have started to be expressed in populations and that forest loss is already building barriers to contemporary gene flow. The concern is that gene flow is a process essential to ensure that the genetic diversity of N. mexicanus populations (and probably of many other forest species) distributed in Mexico is preserved or increased in the long term by maintaining forest connectivity between locations.

Two sibling bare-backed bat species (Pteronotus fulvus and P. gymnonotus) have been traditionally differentiated by their size. However, intermediate specimens between the two species have been found in sympatric populations along southern Mexico and it has been suggested that they may be the outcome of a hybridization process between the two species. We used one mitochondrial (COI), three nuclear markers (PRKCL, STAT5A and RAG2) and 13 microsatellites to explore the evolutionary relationships between these two species and elucidate whether the intermediate morphotypes correspond to hybrid individuals. These markers have been analyzed in sympatric and allopatric populations of the two species plus the closely related species Pteronotus davyi. We confirmed the species-level differentiation of the three lineages (P. fulvus, P. davyi and P. gymnonotus), but the phylogenetic hypotheses suggested by the nuclear and mitochondrial markers were discordant. We confirm that the discordance between markers is due to genetic introgression through the mitochondrial capture of P. fulvus in P. gymnonotus populations. Such introgression was found in all P. gymnonotus specimens across its sympatric distribution range (Mexico to Costa Rica) and is related to expansion/retraction species distribution pulses associated with changes in forest distribution during the Quaternary climate cycles. Microsatellite analyses showed contemporary genetic contact between the two sympatric species and 3.0% of the samples studied were identified as hybrids. In conclusion, we found a historical and asymmetric genetic introgression (through mitochondrial capture) of P. fulvus into P. gymnonotus in Mexico and Central America and a limited contemporary gene exchange between the two species. However, no relationship was found between hybridization and the intermediate-sized specimens from southern Mexico, which might likely result from a clinal variation with latitude. These results confirm the need for caution when using forearm size to identify these species in the field and when differentiating them in the laboratory based on mitochondrial DNA alone.

The Big Naked-backed Bat, Pteronotus gymnonotus, is one of the 15 species currently recognized of this genus, with relatively few specimens in scientific collections, besides being poorly studied.  It has a geographical distribution spanning from  México through Central America and reaching Perú and Brazil, in which it occupies a variety of habitats from desert to tropical forests below 400 meters above sea level.  Here, we report the records that demonstrate its presence, and data about its natural history in southeastern  México, the northernmost part of its geographic distribution range.  Between June 2002 and July 2018, we captured specimens in 44 bat roosts located in southeastern  México, including the Parque Estatal Agua Blanca, Macuspana, Tabasco; Grutas de Martínez de la Torre, Matías Romero Avendaño, Oaxaca; and in Cueva de Villa Luz, Tapijulapa, Tabasco.  In the three locations mentioned, we recorded the occurrence of P. gymnonotus individuals, whose taxonomic identification at species level was corroborated by both morphological data and genetic analyses.  Previously, the only records of P. gymnonotus in  México were from only four specimens scattered across time, so these new recorded locations confirm the presence of this species in the country.  In addition to this, in Agua Blanca State Park and Villa Luz Cave we found a reproductive resident population.  The record from Grutas de Martínez de la Torre is located in the middle of the Tehuantepec Isthmus, a well known biogeographical barrier for many taxa in the transitional area to the Pacific lowland’s region.  We suggest that the occurrence of P. gymnonotus in México is also associated with large remnants of evergreen and gallery forests, located in the lowland areas along the Gulf of  México and in the north and east of the Tehuantepec Isthmus.

We describe a population of pipistrelle-like bats from Príncipe Island (Gulf of Guinea, Western Central Africa) as a new species based on the molecular and morphological characteristics of six specimens collected more than 30 years ago. The description of this new species was not possible until the traditionally entangled systematics of the whole pipistrelle group was clarified in recent years with the inclusion of molecular techniques and adequate species sampling. In this new taxonomic framework, the new species was clearly included within the dark-winged group of the recently described genus Pseudoromicia. The pipistrelles from Príncipe Island present a moderately inflated skull in lateral view with inner upper incisors that are moderately bicuspids and a baculum distinctly long with expanded tips. Besides these morphological characters, the new bat species is distinguished by its dwarfism, being the smallest species recognized within the genus. The ecology and conservation status of this endemic island species are unknown and field studies are urgently needed to evaluate the situation and conservation threats to this new species in its natural habitat.

We report the first prey species consumed by the free-ranging Van Gelder’s bat Bauerus dubiaquercus. We trapped four pregnant individuals of this species carrying freshly captured dung beetles. We describe the wing morphology and flight descriptors (wing loading and wing aspect ratio) of the species, which presents wings more suitable for capturing insects by aerial hawking, although the evidence suggests that is able to capture dung beetles of nearly 10% of its body mass in flight close to the ground. The species could obtain their prey while foraging on uncluttered pasture near forest edges.

Pteronotus psilotis, a mormoopid bat, is an insectivorous, gregarious and strict cave-dwelling species that is found areas between the sea level and an elevation of about 1000 masl. This species is present in diverse habitats ranging from rain forest to dry deciduous forest. Nine microsatellite loci were developed for Wagner's mustached bat, Pteronotus psilotis using the next-generation sequencing approach, and their utility for population genetics studies was assessed. All loci were polymorphic (7-15 alleles) and characterized in 30 individuals from three P. psilotis populations, with the levels of observed and expected heterozygosity ranging from 0.280 to 0.867 and 0.584 to 0.842, respectively. One locus showed significant departures from Hardy-Weinberg expectations after Bonferroni correction. Cross-amplification in 11 other bat species was tested, for which eight microsatellites were successfully amplified, and of these seven were polymorphic. The development of these new microsatellite loci will contribute to investigations of genetic population structure, genetic diversity and gene flow in P. psilotis populations, as well as in other closely related bat species.