Isara Patawang

Cytogenetics of the skinks (Reptilia, Scincidae) from Thailand; IV: newly investigated karyotypic features of Lygosoma quadrupes and Scincella melanosticta

Abstract This study analyzed the karyotype of Lygosoma quadrupes and Scincella melanosticta from northeastern Thailand. Mitotic chromosomes were prepared directly from intestinal epithelial cells of three L. quadrupes and nine S. melanosticta. The chromosomes were stained by conventional staining technique. The karyotype was determined for each species based on at least 20 well-spread cells. Both L. quadrupes and S. melanosticta showed the same diploid number of 2n = 30, but differed in identical chromosome morphology. No sex chromosome heteromorphisms were evident in L. quadrupes; in contrast, S. melanosticta showed the ZZ/ZW sex determination system. The respective karyotype formulae of L. quadrupes and S. melanosticta were deduced as:

Cytogenetics of the skinks (Reptilia, Scincidae) from Thailand; III: the first karyological study of Sphenomorphus maculatus and Jarujinia bipedalis

Abstract This is a karyological study of male and female Sphenomorphus maculatus from Khon Kaen Province in Northeastern Thailand, and female Jarujinia bipedalis from Kanchanaburi Province in Central Thailand. Chromosomes of two species were prepared by the squash technique from the bone marrow and testis. Conventional staining and Ag-NOR banding techniques were applied to stain the chromosome with Giemsa’s solution and silver nitrate solution, respectively. The results showed that the diploid chromosome number of Sphenomorphus maculatus and Jarujinia bipedalis was 30 and the fundamental number (NF) was 44. There were eight large metacentric, two medium metacentric, four small metacentric and 16 microchromosomes in Sphenomorphus maculatus and eight large metacentric, six small metacentric, two small telocentric and 14 microchromosomes in Jarujinia bipedalis. There was no irregularly sized chromosome related to sex in either species. For Sphenomorphus maculatus, NORs are located at the telomere on the long arms of the second pair of the metacentric chromosome. The karyotype formulae were deduced as: 2n (30) = Lm8 + Mm2 + Sm4 + 16 microchromosomes and 2n (30) = Lm8 + Sm6 + St2 + 14 microchromosomes for Sphenomorphus maculatus and Jarujinia bipedalis, respectively.

Additional description of karyotype and meiotic features of Takydromus sexlineatus (Squamata, Lacertidae) from northeastern Thailand

This study determined the standardized karyotype and idiogram of Takydromus sexlineatus from Surin Province in northeastern Thailand. Mitotic metaphase chromosomes from bone marrow cells and different meiotic stage from testicular cells respectively were studied after staining with conventional Giemsa and Ag-NOR banding techniques for chromosome identification. The study was carried out with samples taken from both male and female T. sexlineatus, the sex of which was identified by external examination. The results showed that the diploid chromosome number of T. sexlineatus was 2n = 38 and the fundamental number (NF) was 38 in both male and female. Although chromosome study was done in both sexes of T. sexlineatus, this study does not identify the sex chromosomes. This is because of the limitation of the staining techniques used. Therefore, we did not conclude on the sex chromosome system in this species and all chromosomes were taken as autosomes. The types of autosomes observed were 16 large telocentric, 14 medium telocentric, and 6 small telocentric macrochromosomes and 2 microchromosomes. Our result is the new record in Thailand on this species and NOR characteristics by silver staining is the first report on NOR banding in this species. The karyotype formula of T. sexlineatus thus was found as: 2n(38) = L16t + M14t + S6t + 2 microchromosomes.

A new review and karyological analysis of Leiolepis belliana and L. boehmei (Reptilia, Agamidae) from a population in southern Thailand

ABSTRACT The diploid number of both Leiolepis belliana and L. boehmei was 2n = 2x = 36. In addition, the karyotype of the two species exhibited many conserved characteristics, including six pairs of macrochromosomes and 12 pairs of microchromosomes, the type and size of the macrochromosomes, and the position of the secondary constriction and nucleolar organizer region (NOR). However, while the position of the NOR region was identical in both species, in L. belliana it was found on both chromosomes of the first pair, and in L. boehmei it appeared on only one of the chromosome of the first pair, classified as 1a. No cytologically distinguishable sex chromosome was observed in either species. The karyotype formulae of L. belliana and L. boehmei were identical: 2n (36) = Lm4 + Mm6 + Sm2 + 24 microchromosomes.