Gliding behaviour of Indian giant flying squirrel (Petaurista philippensis)

The Indian giant flying squirrel or large brown flying squirrel, Petaurista philippensis (Elliot, 1839) is one of 13 gliding squirrel species found in India. Nocturnal by nature, they have ability to glide up to 150 m. We studied its gliding habit in the human-modified landscape of the Kevdi ecotourism site (22.5198ºN, 73.9356ºE; Fig. 1), Panchmahal District, between two protected areas in Gujarat: Ratanmahal Sloth Bear Sanctuary and Jambughoda Wildlife Sanctuary. The Kevdi ecotourism site is a known locality of this species. Here, we present basic information on the gliding ecology of the species in the dry deciduous forests of central Gujarat.

A de novo genome assembly and annotation of the southern flying squirrel (Glaucomys volans)

Northern (Glaucomys sabrinus) and southern (Glaucomys volans) flying squirrels are widespread species distributed across North America. Northern flying squirrels are common inhabitants of the boreal forest, also occurring in coniferous forest remnants farther south, whereas the southern flying squirrel range is centered in eastern temperate woodlands. These two flying squirrel species exhibit a hybrid zone across a latitudinal gradient in an area of recent secondary contact. Glaucomys hybrid offspring are viable and can successfully backcross with either parental species, however, the fitness implications of such events are currently unknown. Some populations of G. sabrinus are endangered, and thus, interspecific hybridization is a key conservation concern in flying squirrels. To provide a resource for future studies to evaluate hybridization and possible introgression, we sequenced and assembled a de novo long-read genome from a G. volans individual sampled in southern Ontario, Canada, while four short-read genomes (two G. sabrinus and two G. volans, all from Ontario) were resequenced on Illumina platforms. The final genome assembly consisted of approximately 2.40 Gb with a scaffold N50 of 455.26 Kb. benchmarking universal single-copy orthologs reconstructed 3742 (91.2%) complete mammalian genes and genome annotation using RNA-Seq identified the locations of 19,124 protein-coding genes. The four short-read individuals were aligned to our reference genome to investigate the demographic history of the two species. A principal component analysis clearly separated resequenced individuals, while inferring population size history using the pairwise sequentially Markovian coalescent model noted an approximate species split 1 million years ago, and a single, possibly recently introgressed individual.

Distribution and habitat use of the endangered Siberian flying squirrel Pteromys volans (Rodentia: Sciuridae)

Background Understanding the habitat characteristics of the endangered Siberian flying squirrel Pteromys volans is the first step in conserving and managing the forests it requires for nesting, gliding, and feeding. Therefore, in the present study, we characterized the habitats of P. volans using GIS analysis of 411 forest sites in South Korea where fecal droppings were found. Results Fecal signs of P. volans were found in various regions in South Korea, including the Baekdudaegan Mountains. GIS analysis with six environmental layers (vegetation type, wood-age class, diameter at breast height [DBH], crown density, elevation, and distance from stream) revealed that fecal signs of P. volans were more frequently found in broad-leaved deciduous forests (42%) located 200–399 m above sea level (43.1%) and 0–199 m from the nearest stream (53%), with 5th class wood-age (35.3%), middle size class DBH (51.1%), and high crown density (71%). Conclusions The present study provides information on the biotic and abiotic characteristics of P. volans habitats. In South Korea, the fecal droppings of P. volans were found predominantly old deciduous broadleaf forests. Further studies are needed to reveal whether the more frequent occurrence of P. volans dropping in broadleaf forests may be due to a particular preference of this species for the forests or to a simple reflection of the area of the broadleaf forests occupying a much larger area than other forest types in Korea.

Using mass spectrometry to investigate fluorescent compounds in squirrel fur

While an array of taxa are capable of producing fluorescent pigments, fluorescence in mammals is a novel and poorly understood phenomenon. We believe that a first step towards understanding the potential adaptive functions of fluorescence in mammals is to develop an understanding of fluorescent compounds, or fluorophores, that are present in fluorescent tissue. Here we use Fourier transform-ion cyclotron resonance mass spectrometry (FT-ICR MS) of flying squirrel fur known to fluoresce under ultraviolet (UV) light to identify potentially fluorescent compounds in squirrel fur. All of the potentially fluorescent compounds we identified were either present in non-fluorescent fur or were not present in all species of fluorescent flying squirrel. Therefore, we consider that the compounds responsible for fluorescence in flying squirrels may also be present in non-fluorescent mammal fur. Some factor currently unexplained likely leads to excitation of fluorophores in flying squirrel fur. A recently suggested hypothesis that fluorescence in mammals is widely caused by porphyrins is consistent with our findings.

A de novo genome assembly and annotation of the southern flying squirrel (Glaucomys volans)

Northern (Glaucomys sabrinus) and southern (Glaucomys volans) flying squirrels are widespread species distributed across much of North America. Northern flying squirrels are common inhabitants of the boreal forest, also occurring in coniferous forest remnants farther south, whereas the southern flying squirrel range is centered in eastern temperate woodlands. These two flying squirrel species exhibit a hybrid zone across a latitudinal gradient in an area of recent secondary contact. Glaucomys hybrid offspring are viable and can successfully backcross with either parental species, however, the fitness implications of such events are currently unknown. Some populations of G. sabrinus are endangered, and thus, interspecific hybridization is a key conservation concern in flying squirrels. We sequenced and assembled a de novo long-read genome from a G. volans individual sampled in southern Ontario, Canada, while four short-read genomes (2 G. sabrinus and 2 G. volans, all from Ontario) were re-sequenced on Illumina platforms. The final genome assembly consisted of approximately 2.40Gb with a scaffold N50 of 455.26Kb. Benchmarking Universal Single-Copy Orthologs reconstructed 3,742 (91.2%) complete mammalian genes, and genome annotation using RNA-seq identified the locations of 19,124 protein-coding genes. The four short-read individuals were aligned to our reference genome to investigate the demographic history of the two species. A Principal Component Analysis clearly separated re-sequenced individuals, while inferring population size history using the Pairwise Sequentially Markovian Coalescent model noted an approximate species split one million years ago, and a single, possibly recently introgressed individual.