The lace-sheet-weavers—a long story (Araneae: Psechridae: Psechrus)

Abstract

Various publications of the last twelve years have shown that the species richness of the genus Psechrus is much higherthan was assumed 30 years ago. Based upon trends in the structures of the copulatory organs, for the first time, eight spe-cies groups are recognised and, including the present study, 46 species are now known. 20 species are recognised anddescribed as new: P. ulcus sp. nov., P. aluco sp. nov., P. decollatus sp. nov., P. elachys sp. nov., P. norops sp. nov., P.arcuatus sp. nov., P. laos sp. nov., P. inflatus sp. nov., P. pakawini sp. nov., P. demiror sp. nov., P. jaegeri sp. nov., P.vivax sp. nov., P. obtectus sp. nov., P. fuscai sp. nov., P. clavis sp. nov., P. hartmanni sp. nov., P. zygon sp. nov., P. tauri-cornis sp. nov., P. crepido sp. nov. and P. schwendingeri sp. nov. Two species are removed from synonymy with P. sin-gaporensis Thorell, 1894: P. annulatus Kulczyński 1908 (stat. nov.) and P. libelti Kulczyński 1908 (stat. nov.). One juniorsynonym of P. tingpingensis Yin, Wang & Zhang, 1985 is recognised: P. xinping Chen, Zhang, Song & Kim, 2002 (syn.nov.). New records are reported: P. libelti from Thailand, Malaysia & Brunei; P. ancoralis Bayer & Jäger, 2010 from Thai-land; P. himalayanus Simon, 1906 from Bhutan; P. ghecuanus Thorell, 1897 from Laos. Pre-epigynes/pre-vulvae of 20Psechrus species are examined and illustrated. In these species they apparently exhibit consistent and species-specificcharacters. However, since in several species only one subadult female was available for examination and in 57% of thePsechrus species even none at all, the characters of the pre-epigyne/pre-vulva are not included in the Psechrus identifica-tion key introduced herein. Additional information on the biology of Psechrus—for which the trivial name “lace-sheetweavers” is introduced herein—is provided.

Seven new species of Psechrus and additional taxonomic contributions to the knowledge of the spider family Psechridae (Araneae)

“…In males of the mulu-group tibial processes (again?) appear, either ventrodistally or retrolatero-distally (Levi 1982;Bayer 2012). The latter situation is exhibited by P. ulcus Bayer, 2012.…”

“…The spider family Psechridae has been revised several times (Levi 1982;Wang & Yin 2001;Bayer 2011Bayer , 2012. In the latest revisions of Fecenia Simon, 1887 (Bayer 2011) and Psechrus Thorell, 1878(Bayer 2012, both genera have been revised on a worldwide basis. Nevertheless, the state of knowledge on many species is incomplete and questions remain.…”

“…Nevertheless, the state of knowledge on many species is incomplete and questions remain. In some species structural intraspecific variation of female copulatory organs is remarkably high, for example in Psechrus khammouan Jäger, 2007 the respective variants were considered to belong to the same species (Bayer 2012), but, due to the lack of material, without 100% certainty. On the other hand there are species showing remarkable similarities to others distributed nearby.…”

“…Several previously unknown forms of Psechrus are now recognised, described and as far as possible assigned to one of the eight Psechrus species groups established by Bayer (2012). These species groups are based mainly on characters of the copulatory organs (but also upon several somatic characters, such as the spination of the dorsal tibia III and IV, the colouration of the carapace or the relative length of the legs) (Bayer 2012). Besides the Psechrus specimens, one Fecenia protensa Thorell, 1891 female from Vietnam showing special morphological features became available.…”

“…Some species investigated herein were (additionally) represented by subadult females. Bayer (2011Bayer ( , 2012 suggested that species discrimination based on primordial female copulatory organs (preepigynes/pre-vulvae) is possible for Fecenia species and may be possible for Psechrus species as well. Therefore, besides the adult material, this study also focusses on subadult females.…”