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.

A new species of Endangered giant trapdoor spider (Mygalomorphae: Idiopidae: Euoplos) from the Brigalow Belt of inland Queensland, Australia

“…This tribe was recovered as the sister-group to all other Australasian Idiopidae in recent phylogenetic analyses (Rix et al 2017a; Wilson et al 2020). Species of Euoplos are small to very large Idiopidae from both eastern and western mainland Australia, all of which build hard, plug-like ‘soil + silk’ doors, as opposed to flap-like ‘leaf litter + silk’ doors in most species of Cryptoforis (Wilson et al 2020). Males of Euoplos , like those of Bungulla Rix, Main, Raven & Harvey, 2017 and a number of species in other Australian idiopid genera, are unusual in lacking paired clasping spurs on the distal prolateral tibia I, and both male and female Euoplos are generally characterized by relatively conservative somatic and genitalic morphologies, with the remarkable exception of the mcmillani -group of ‘white-headed trapdoor spiders’ from south-western Western Australia (see Rix et al 2019a).…”

“…Along with the genus Cryptoforis Wilson, Rix & Raven, 2020, which was separated from Euoplos and newly described in 2020, the genus Euoplos belongs the monophyletic tribe Euoplini Rainbow, 1914. This tribe was recovered as the sister-group to all other Australasian Idiopidae in recent phylogenetic analyses (Rix et al 2017a; Wilson et al 2020). Species of Euoplos are small to very large Idiopidae from both eastern and western mainland Australia, all of which build hard, plug-like ‘soil + silk’ doors, as opposed to flap-like ‘leaf litter + silk’ doors in most species of Cryptoforis (Wilson et al 2020).…”

“…The ‘golden trapdoor spiders’ of the genus Euoplos Rainbow, 1914 are among Australia’s best-known mygalomorph spiders, having been the subject of an extensive research program since 2017 aimed at understanding the diversity, phylogeny, biogeography and biology of this distinctive group (Rix et al 2017a, c, 2019a, b; Wilson et al 2018, 2019, 2020, 2021; Wilson & Rix 2021). Along with the genus Cryptoforis Wilson, Rix & Raven, 2020, which was separated from Euoplos and newly described in 2020, the genus Euoplos belongs the monophyletic tribe Euoplini Rainbow, 1914. This tribe was recovered as the sister-group to all other Australasian Idiopidae in recent phylogenetic analyses (Rix et al 2017a; Wilson et al 2020).…”

“…However, a number of other undescribed inland species are also known, including a new species from west of Theodore, central Queensland (JDW, unpubl. data), Euoplos “Burren Junction” and Euoplos “Orange” from inland New South Wales (Wilson et al 2020; Fig. 1), Euoplos ‘Quinkan’ from Cape York Peninsula (Wilson et al 2020; Fig.…”

Taxonomic revision of the Neotropical spiders of the genus Idiops Perty, 1833 (Araneae, Idiopidae), with description of four new species

“…The idiopids are currently the third most diverse mygalomorph family, comprising 434 species in 23 genera (World Spider Catalog 2021). Despite this potential, only genera belonging to the subfamily Arbanitinae have recently been systematically reviewed, which have also formed the basis of subsequent biogeographic studies (Rix et al 2017a(Rix et al , 2017bWilson et al 2018Wilson et al , 2020.…”