First report of karyological analysis and heteromorphic nucleolar organizer region of Black Surgeonfish (Acanthurus gahhm, Acanthuridae) in Thailand

This research was the first report on karyological analysis and heteromorphic nucleolar organizer region of black surgeonfish (Acanthurus gahhm, Acanthuridae) in Thailand. The 10 male and 10 female specimens were collected from Phuket Marine Biological Center, and Phang Nga Coastal Research and Development Center, Andaman Sea, Thailand. Mitotic chromosomes were directly prepared from gill and kidney tissues. The chromosomes were stained by conventional Giemsa staining and Ag-NOR banding techniques. Results showed that the diploid chromosomes number of A. gahhm was 2n=48, the fundamental numbers (NF) was 54 in both male and female. The karyotype consist of 6 large acrocentric, 20 large telocentric, 18 medium telocentric and 4 small telocentric chromosomes. None of strange size chromosomes related to sex was found. The heteromorphic nucleolar organizer regions (NORs) were observed on telomeric short arm of first acrocentric which can defined as 1a1b. There is NOR in 1a and not in 1b. The karyotype formula of black surgeon fish was as follows: 2n (48) = La6+Lt20+Mt18+St4

New Transbaikalian finds of the Muja Valley vole (Rodentia: Cricetidae: Alexandromys mujanensis)

The Muja vole, Alexandromys mujanensis Orlov et Kovalskaya, 1975, was described in the result of the karyological analysis and experimental hybridization. Since the first description the Muja vole has been considered to inhabit only the Muja Valley. Some Far Eastern voles were collected in 2013 and 2014 from the Dzherginsky Nature Reserve of the Barguzin Valley (Dzhirga sample), and the Baunt Lake vicinity (Baunt sample) (Transbaikalia, Buryatia). The species from these geographic localities were identified by use of karyotypic and cytb-gene analyses. On the cytb-gene tree these voles are in the same clade with Muja voles from the type locality (the Muja Valley). The karyotype of the vole from Barguzin Valley corresponds to that previously described for the Muja voles (Meyer et al. 1996). According to the result of the shape analysis of m1 occlusal surface the sample from the Baunt Valley includes two species – A. mujanensis and A. maximowiczii. Unless more detailed analysis of the material from the different parts of the Baunt Valley is carried out, we suppose it to be inhabited by three species – A. maximowiczii, A. mujanensis, and according to the data from literature – A. oeconomus. So far as some molecular-genetic differences between Muja voles from the Dzhirga and Baunt Lake vicinity were found, the experiments on hybridization between them were set. The F1 hybridization between them were fertile. A. mujanensis taxonomic position and terms of its origination are discussed.