Dwarf spiders: Function and evolution of secretory prosomal structures.

Dwarf spiders (Araneae, Linyphiidae) have drawn much attention to their high diversity of sexually dimorphic male prosomal structures. These external modifications are associated with internal glandular tissues that produce a nuptial gift, which the female takes up during mating. The widely distributed, species-rich dwarf spider genus Oedothorax exhibits a high intrageneric variation in these male structures. Thus, the study of their phylogeny will give us insight into the history and pattern of the evolution of these sexually selected features, and the effect of sexual selection on speciation. So far, we have inferred from the morphological characters that the species currently hosted in the genus Oedothorax are not monophyletic, and that the various features on the male prosoma have evolved several times independently. Micro-CT reconstruction of the internal dimension of glandular tissues provides a potential means to evaluate homology of similar prosomal structures among different taxa. These results will lead to major changes in dwarf spider taxonomy, and an increased understanding on the evolutionary pattern of sexually dimorphic characters.

In addition, Shou-Wang Lin conducted a survey of Taiwanese Linyphiidae, which resulted in the discovery of over 10 new species of the genus Shaanxinus Tanasevitch, 2006. This genus was represented previously by only two species from China. Currently, he is describing new species of Shaanxinus, inferring interspecific relationships by phylogenetic analyses, and tackling issues about DNA barcoding.

Collaborations:

Nikolaj Scharff

several natural history museums