Tsushima martens (Martes melampus tsuensis) are medium-sized terrestrial mammal distributed in Tsushima Island, Japan, and listed as a near threatened species by the Ministry of the Environment, and designated as a natural monument of Japan. The purpose of this study was to investigate the breeding season and sexual maturity by the testicular temporal changes, and obtain the knowledge about baculun morphology, and attempt to determine the age using the baculum in this subspecies. Twenty-one wild male Tsushima martens were collected during 1994－2012 on Tsushima Island. The testes and bacula were measured and observed macroscopically and histologically. Age was determined by counting the annual layers of cementum. In the animals over one year (≥1-yr) of age, the testis length and seminiferous tubule diameter were significantly greater during July－September than those during January－March or October－December. In the seminiferous tubule of ≥1-yr animals during July－September, spermatogonia to spermatozoa were observed. Thus, the breeding season was estimated to occur during July－September, and the animals were estimated to reach sexual maturity during their second year. The baculum morphology of the Tsushima marten is thought to be the dominant type found in the Martes species. The baculum weight increased with age, and there were significant differences between 0 yr, 1 yr, and ≥2 yr. From this, it is possible to estimate the age of a Tsushima marten by using the baculum weight.
We examined the partial mitochondrial DNA sequences of the Ryukyu long-furred rats (Diplothrix legata) on northern Okinawa-jima Island to evaluate the genetic diversity of this species. Complete mitochondrial D-loop (40.933) and partial tRNA-Pro (1.39) and Phe (934.961) sequences, totaling 961 bp in length, were determined for 60 individuals. Three D-loop haplotypes were present in these animals, with mutations at six sites (GenBank accession numbers: AB699876-AB699878). The haplotype diversity (H) and the nucleotide diversity (π) of the D-loop sequences were 0.606 and 0.00238, respectively. The “twin-peak” phenomenon was observed for the mismatch distribution of pairwise differences, indicating that the population of these animals had experienced a population bottleneck.
Genet ic assessment of gibbon populations is required to establish and develop the conservation management of endangered gibbon species. To assess the paternal genetic diversity of wild gibbons, we searched and developed six loci of the Y-chromosomal marker that consist of five microsatellites and three PCR fragment length polymorphisms in two species of gibbons, Hylobates lar (white-handed gibbons) and H. pileatus (pileated gibbons). Using these Y-chromosomal markers, no individual shared a Y-chromosomal haplotype with any other individual among captive H. lar (n = 12) and H. pileatus (n = 5). The application of the Y-chromosomal markers developed in this study will help us to uncover the genetic diversity of these two gibbon species.