Uncharted diversity and evolutionary history of Neotropical samooid harvestmen (Opiliones: Laniatores: Samooidea)

ABEL PEREZ GONZALEZ; DANIEL N. PROUD

Golden

Congreso; The 20th International Congress of Arachnology; 2016

ICA, AAS

The superfamily Samooidea is a diverse group of laniatorean harvestmen that is comprised of 212 species divided into three families. The systematics of this lineage is investigated and, using an integrative taxonomic approach based on molecular and morphological evidence, a new taxonomic arrangement is proposed. We present the first dated molecular phylogeny of the Samooidea and discuss the ways in which the shifting landscape of the Caribbean has shaped the opiliofauna of the region over the past 50 million years ? with dispersal and vicariance both contributing to present day diversity and distributions. Of particular interest is Neoscotolemon, a genus that currently consists of only two described species although we have discovered more than 20 additional species during our work. This indicates that the diversity of this genus is greatly underestimated ? a pattern that we have observed to be relatively common for genera that consist of small litter dwelling harvestmen in the Neotropics. The genus Neoscotolemon enables us to illustrate the dynamic two-way interchange that occurs between islands and nearby continents, likely via dispersal. This phenomenon has recently garnered the attention of many of those studying island biogeography, and lends support to the idea that islands can serve as both evolutionary museums and cradles of diversity.