Chromosome studies in the genus Pterotricha (Gnaphosidae) from Turkey

The diploid chromosome set and male meiosis of two spider species belonging to the family Gnaphosidae from Turkey are described. Both Pterotricha kochi and Pterotricha lesserti exhibited the diploid chromosome number as 2n♂=22 and X1X20 sex chromosome type. All chromosomes were acrocentric. During the first meiotic division, both species had ten autosomal bivalents and two sex chromosomes that were positively heteropycnotic. At the second meiotic division, two kinds of nuclei were determined, with or without sex chromosome. These data will contribute to our knowledge of the evolution of the genus Pterotricha.