Modisimus on Hispaniola: unimagined diversity
(published in Zool. J. Linn. Soc. 158 (2010): 244-299)
 

Previously, only four extant species of Modisimus were known from Hispaniola, represented by a total of seven specimens. During two trips to the Dominican Republic and Haiti I came across Modisimus in literally every patch of forest and collected over 700 adult specimens representing 30 species. This highlights the immensity of unknown diversity present on this Caribbean biodiversity hotspot.

In this study we redescribe three of the four previously known species and describe 22 new species. Most Haitian species are local endemics, either of the severely threatened forests in one of the two national parks or their surrounding areas. Phylogenetic analysis indicates that most of these species together represent a species group that is restricted to the paleogeographically distinct southern ‘paleoisland’ and that is otherwise known neither from Hispaniola nor from any other island.

We sequenced two mitochondrial markers (16S, CO1) to test for their performance as barcoding genes within this group of partly closely related species. Both markers unambiguously corroborated the morphospecies, with small but distinct gaps between intra- and interspecific genetic distances.

In contrast to many other pholcids, most Hispaniolan Modisimus are easily distinguished even when only females are available. Below are photos of the species treated, documenting this unusual variation.

modisimus

Photos: B. A. Huber and N. Fischer