Discovery of the genus Eukoenenia (Palpigradi: Eukoeneniidae) from China and description of a new species

Abstract

Abstract. A new species, Eukoenenia sinensis, is described and illustrated from specimens collected in two forests in nearby islands in Guangdong Province, Southeast China. The genus Eukoenenia is recorded for the first time from China and it represents the second palpigrade species reported for this country after Koeneniodes madecassus Rémy, 1950. The new species shares several morphological characters with other soil-dwelling Eukoenenia species from Africa, Asia and South America. One of the distinctive characters of E. sinensis is the presence of 6 pairs of setae (a1, a2, a3, a4 þ s1, s2) on opisthosomal sternites IV to VI, a character only shared with another five species. Eukoenenia sinensis is most similar to specimens captured from Chile and identified by Dr. Bruno Condé as Eukoenenia cf. grassii; several morphological and morphometric features allow to differentiate both species. From the other four species, two can be readily distinguished by their troglomorphic characters, and the other two are soil-dwelling species that show differences in the chaetotaxy of basitarsus IV, metapeltidium, deutotritosternum, opisthosomal tergites III–VI, as well as the number of teeth in the cheliceral fingers. In addition, E. sinensis is the first palpigrade to exhibit sexual dimorphism in the number of thick setae of coxa IV.