Total-evidence analysis of an undescribed fauna: resolving the evolution and classification of Australia's golden trapdoor spiders (Idiopidae: Arbanitinae: Euoplini).

Abstract

In the trapdoor spider genus Euoplos Rainbow & Pulleine (tribe Euoplini), it was discovered recently that two divergent lineages occur in sympatry in eastern Australia. This challenged the monogeneric classification of the tribe and, in combination with inadequate taxonomic descriptions of some species, precluded comprehensive taxonomic revision. To resolve these issues, we conducted a total-evidence cladistic analysis on a largely undescribed continental fauna-the first such analysis on a group of Australian Mygalomorphae. We combined multilocus molecular data and/or morphological and behavioural data from all known species from eastern Australia (described and undescribed), plus a subset of Western Australian species, to produce a phylogeny for the tribe. We mapped morphological/behavioural characters onto this to identify clade-specific diagnostic characters, and applied these data to a generic reclassification of the tribe. We recovered two sympatric lineages in the Euoplini (the "wafer-door" and "plug-door/palisade" lineages), and revealed the phylogenetic position of all known eastern Australian species within these. Character mapping revealed morphological and behavioural (burrow architecture) features that allow diagnosis of the lineages and clades within them. We erect a new genus, Cryptoforis gen.n., to represent the wafer-door lineage, describe the type species, Cryptoforis hughesae sp.n., and transfer two species from Euoplos to Cryptoforis: C.tasmanica (Hickman, 1928) and C.victoriensis (Main, 1995). This study resolves phylogenetic structure within the Euoplini, and characterizes clades within the tribe to facilitate future taxonomic revisions. It also demonstrates that, whereas male morphology is more informative, female morphological characters relating to genitalia and the scopulation/spination of the anterior legs display phylogenetic signal in the Euoplini, highlighting the subtle nature of informative female characters in mygalomorph spiders.