Chromosome evolution in lycosoid spiders (Araneomorphae): a scenario based on analysis of seven species of the families Lycosidae, Senoculidae and Trechaleidae

Abstract Within the araneomorph lineage Entelegynae, the “Higher lycosoids” (“True Lycosoids” or Lycosoidea s.s.) is one of the major clades varying in its composition based on several conflicting phylogenetic hypotheses. So far, only a few species have been studied cytogenetically. In this work, the chromosomes of a senoculid spider were investigated for the first time, along with a cytogenetic analysis of six species of the families Lycosidae and Trechaleidae. Mitotic metaphase cells of the lycosid species revealed 2n♂ = 18 + X0 in Hogna sternalis (Bertkau 1880) and Lycosa nordenskjoldi Tullgren 1905, and 2n♂ = 20 + X1X20 in Lycosa erythrognatha Lucas 1836 and Lycosa sericovittata Mello-Leitao 1939. Chromosomal analysis of the trechaleid and senoculid species showed 2n♀ = 22 in Neoctenus comosus Simon 1897 (Trechaleidae), and 2n♂ = 26 + X1X20 in Syntrechalea syntrechaloides (Mello-Leitao 1941) (Trechaleidae) and Senoculus sp. (Senoculidae). This latter karyotype is a shared feature in most species of Ly...