Finding hot singles: matching males to females in dimorphic spiders (Araneidae: Micrathena) using phylogenetic placement and DNA barcoding.

PEDRO HENRIQUE MARTINS; IVAN LUIZ FIORINI DE MAGALHÃES; ADALBERTO J. SANTOS; ANDRÉ AMARAL NOGUEIRA

Buenos Aires

Congreso; The XXXV Annual Meeting of the Willi Hennig Society; 2016

Many orb-weaving spiders exhibit remarkable sexual dimorphism, hampering the matching of males and females in taxonomic studies. This is the case for the spiny Micrathena spiders, a species-rich Neotropical genus with 27% of its species known from a single sex. We found several undescribed Micrathena specimens, and tested whether they belong to some of those incompletely known species. For that, we tested the phylogenetic position of males and their putative females using a previous morphological dataset. Unmatched males and females were coded as separate taxa (with missing entries for all feminine and masculine characters, respectively) in a matrix also including several species known and coded from both sexes. We checked whether unmatched males and females were recovered in the same morphological groups. These results have been cross-validated with 1) genetic distances among individuals based on a fragment of the mitochondrial gene COI and 2) their geographical distributions. This approach allowed us to identify and describe the previously unknown males of six species, and the female of M. beta di Caporiacco. Furthermore, in three species previously known from both sexes, males had been incorrectly matched with females, and one of those actually belongs to a hitherto unnamed species. After associating males to the correct females, we re-estimated the phylogeny of the genus with each newly matched species coded for both male and female characters. Our study highlights the importance of using different sources of data for matching the sexes in diverse groups with strong sexual dimorphism.