Karyotypová evoluce stepníkovitých pavouků (Araneae: Eresidae)

Abstract

Presented study is aimed to determine basic trends of karyotype evolution in velvet spiders (Eresidae; Araneae). Eresids are burrowing spiders; they includes also some social species. Karyotypes of 16 species of the family Eresidae as well as 2 species of the other families of the superfamily Eresoidea, Hersiliidae and Oecobiidae, are presented. Furthermore, DNA content and base proportion was determined in 14 species. In two species, DNA content of sex chromosomes was also measured. Obtained results revealed considerable variability of diploid numbers, and sex chromosomes systems in eresids. Obtained karyotype data allow to divide eresids into four groups. Karyotypes of the genera Gandanameno, Dresserus and S. lineatus are close to proposed ancestral karyotype of entelegynae spiders and they show the ancestral state of karyotype in velvet spiders. Karyotypes of S. lineatus and E. annulipes differ substantially from other representatives of the genera Stegodyphus and Eresus which indicates paraphyly of these genera. Karyotypes of basal forms are formed by acrocentric chromosomes. Further evolution of eresid karyotypes included considerable reduction of diploid numbers as well as changes of chromosome morphology. Social species of the genus Stegodyphus show tendency to reduce diploid numbers by...