Within the long-term goal of providing a comprehensive description of the tropical Andean fauna, the aim of my first collecting expedition in mainland Ecuador in Sep.-Oct. 2021 was an overview of the pholcid fauna in this counry. The specific aim was to visit as many localities as possible in a wide range of ecoregions rather than to exhaustively sample all the species of a few localities. I was amazed by the wide range of ecosystems within a relatively small area.
Left. Map of new (red) and old (blue) collecting sites, with Pholcidae species found per locality. Right. Map of collecting sites with numbers of new species not found at any other site.
The slightly troglomorphic Priscula Ecu57 sp.n. from Anzu Caves and (for comparison) the epigean Priscula Ecu72 sp.n. from Anzu forest.
Males in the genus Mecolaesthus are often characterized by a hump or ‘inflation’ of the carapace. This hump is sometimes extremely variable within species, i.e. some males in a population appear ‘normal’ while others have extremely exaggerated humps. It has been suspected that this structure is positively allometric, suggesting sexual selection, but sufficiently large samples have never been collected to test this. We collected a fairly large sample of the new species shown below, which should be sufficient to reveal positive allometry if present.
Three males of Mecolaesthus Ecu60 sp.n. from Anzu forest; note extreme variation in carapace ‘inflation’.
