Data from: Phylogenetic treatment and taxonomic revision of the trapdoor spider genus Aptostichus Simon (Araneae, Mygalomorphae, Euctenizidae)

This systematic study documents the taxonomy, diversity, and distribution
of 40 species of the predominately Californian trapdoor spider genus
Aptostichus Simon, 1891. Thirty-three of these species are newly
described: Aptostichus dantrippi, Aptostichus cabrillo, Aptostichus
pennjillettei, Aptostichus asmodaeus, Aptostichus nateevansi, Aptostichus
chiricahua, Aptostichus icenoglei, Aptostichus isabella, Aptostichus
muiri, Aptostichus barackobamai, Aptostichus sinnombre, Aptostichus
hedinorum, Aptostichus aguacaliente, Aptostichus chemehuevi, Aptostichus
sarlacc, Aptostichus derhamgiulianii, Aptostichus anzaborrego, Aptostichus
serrano, Aptostichus mikeradtkei, Aptostichus edwardabbeyi, Aptostichus
killerdana, Aptostichus cahuilla, Aptostichus satleri, Aptostichus
elisabethae, Aptostichus fornax, Aptostichus lucerne, Aptostichus fisheri,
Aptostichus bonoi, Aptostichus cajalco, Aptostichus sierra, Aptostichus
huntington, Aptostichus dorothealangeae, and Aptostichus chavezi. Most of
these species are restricted to the California Floristic Province, a known
biodiversity hotspot. Of the 40 recognized species, over half are
considered to be imperiled or vulnerable and two have likely gone extinct
over the past half-century; the conservation status of only 11 species is
considered to be secure. Using 73 quantitative and qualitative
morphological characters I propose a preliminary phylogeny for the genus
that recognizes four major lineages: the Atomarius, Simus, Hesperus, and
Sierra species groups. Additionally, the phylogenetic analysis indicates
that adaptations favoring the invasion of the arid desert habitats of
southern California have evolved multiple times across the group. The
existence of both desert and non - desert species in three of the four
species groups makes this genus an ideal candidate for the study of the
evolutionary ecology of desert arthropods. A set of molecular characters
based on the contiguous mitochondrial DNA genes 16S-tRNA valine-12S is
used in an independent analysis to assist in placement of specimens into
species. The taxonomy section explicitly identifies the concept employed
in species delimitation. Niche based distribution models are constructed
to predict the ranges of species for which an adequate number of sampling
sites were known.