The phylogeny of dionychan spiders: a combined analysis of sequences and morphology

RAMIREZ, M.J,; GRISWOLD, C.; WHEELER, W.

Golden, Colorado

Congreso; 20th International Congress of Arachnology; 2016

International Society of Arachnology

The Dionycha comprise a large clade of two-clawed spiders and a tuft of tenent setae, including about 30% of the known spider species. Since the loss of the inferior claw and acquisition of adhesive setae is one of the most plastic syndromes in spider evolution, the phylogeny and precise demarcation of Dionycha are contentious. A recent morphological phylogeny produced novel synapomorphies for large dionychan clades, and the molecular data (target gene and transcriptomic, published and in progress) are helping to define Dionycha and some of their main lineages, and disentangle morphological convergences. Both sources of data are illuminating and largely congruent, but also have important differences, due to different signal and unequal coverage. While morphological analyses are more sensitive to convergence syndromes, sequence data produce groupings without morphological synapomorphies, thus with limited prediction over the taxonomic diversity of spiders. By combining both data sources we provide synapomorphies for important dionychan clades, confirm the monophyly and placement of many families (e.g., the placement of crab spiders among lycosoids, the inclusion of viridasiids in dionycha), and propose new higher rank-clades.