CYTOGENETIC STUDIES ON SIBERIAN SPIDERS

Karyotypes are reported for 24 spider species, of which 1 is represent ed by juveniles, from Western Siberia (environs of Novosibirsk). Chrom osome counts (2n) are as follows: Lycosidae-Pardosa agrestis, P. lugub ris, P. palustris, and P. plumipes, 28 (males); Hygrolycosa rubrofasci ata, 20 (males) and 22 (females); Xerolycosa miniata and X. nemoralis, 22 (males). Thomisidae-Misumenops tricuspidatum and Xysticus sp., 23 (males). Linyphiidae-Erigone atra, Bolyphantes alticeps, Helophora ins ignis, and Taranucnus setosus, 24 (males); Neriene clathrato, 25 (male s). Tetragnathidae-Pachygnatha clercki, 24 (males) and 26 (females); P . listeri, 24 (males). Clubionidae-Clubiona stagnatilis, 24 (males). A raneidae-Singa hamata, 24 (males). Theridiidae-Steatoda grossa, 22 (ma les) and 24 (females). Some uncommon peculiarities were observed: (1) one specimen of P. lugubris showed the region-specific chromatin decon densation visible at diakinesis only; (2) tetraploid pachytene and dia kinetic cells were found in a male Xysticus sp.; (3) all nuclei of P. listeri contained two trivalents. An analysis of the synaptonemal comp lexes of three species (Pardosa sp., Tibellus sp., and Steatoda grossa ) was also performed.