Ecuador 2021
The tropical Andean countries are possibly among the most species rich regions worldwide as far as Pholcidae are concerned, yet the pholcid fauna of this area is very poorly known. In Ecuador, only 14 species have previously been recorded, based on a published total of just 59 specimens.

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.

We visited a total of 38 localities and collected 828 adult specimens that are tentatively assigned to 69 morphospecies (download report here; PDF 12 MB). Of these 69 morphospecies, 62 have in the meantime been supported by CO1 barcodes, so the species number is preliminary but probably close to reality.

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.

A first troglomorphic representative of the genus Priscula was collected in the Rio Anzu caves. It has less pigmentation than congeners and lays fewer eggs per eggsac, but leg length and eye size seem barely affected.

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’.

I am most thankful to Mauricio Herrera from INABIO for being a great companion in the field, and to Diego Javier Inclán Luna, director of INABIO, for his continuous support during all the phases of this project; I also deeply appreciate the help of further staff at INABIO, mainly Francisco José Prieto Albuja, Lucia Paguay, and Alex Pazmino. The 2021 Ecuador trip was financially supported by the Alexander Koenig Stiftung, Bonn (AKS) and by the Instituto Nacional de Biodiversidad, Quito (INABIO).