A Reconsideration of the Classification of the Spider Infraorder Mygalomorphae (Arachnida: Araneae) Based on Three Nuclear Genes and Morphology

Abstract

BackgroundThe infraorder Mygalomorphae (i.e., trapdoor spiders, tarantulas, funnel web spiders, etc.) is one of three main lineages of spiders. Comprising 15 families, 325 genera, and over 2,600 species, the group is a diverse assemblage that has retained a number of features considered primitive for spiders. Despite an evolutionary history dating back to the lower Triassic, the group has received comparatively little attention with respect to its phylogeny and higher classification. The few phylogenies published all share the common thread that a stable classification scheme for the group remains unresolved.Methods and FindingsWe report here a reevaluation of mygalomorph phylogeny using the rRNA genes 18S and 28S, the nuclear protein-coding gene EF-1γ, and a morphological character matrix. Taxon sampling includes members of all 15 families representing 58 genera. The following results are supported in our phylogenetic analyses of the data: (1) the Atypoidea (i.e., antrodiaetids, atypids, and mecicobothriids) is a monophyletic group sister to all other mygalomorphs; and (2) the families Mecicobothriidae, Hexathelidae, Cyrtaucheniidae, Nemesiidae, Ctenizidae, and Dipluridae are not monophyletic. The Microstigmatidae is likely to be subsumed into Nemesiidae. Nearly half of all mygalomorph families require reevaluation of generic composition and placement. The polyphyletic family Cyrtaucheniidae is most problematic, representing no fewer than four unrelated lineages.ConclusionsBased on these analyses we propose the following nomenclatural changes: (1) the establishment of the family Euctenizidae (NEW RANK); (2) establishment of the subfamily Apomastinae within the Euctenizidae; and (3) the transfer of the cyrtaucheniid genus Kiama to Nemesiidae. Additional changes include relimitation of Domiothelina and Theraphosoidea, and the establishment of the Euctenizoidina clade (Idiopidae + Euctenizidae). In addition to these changes, we propose a “road map” for future sampling across the infraorder with the aim of solving many remaining questions that hinder mygalomorph systematics.

New Chummidae (Araneae): quadrupling the size of the clade

“…Whereas the creation of new families is rather commonplace (Bond et al 2012;Polotow et al 2015;Miller et al 2010), the finding of a new spider family on newly collected material has become a very rare event. The monospecific Trogloraptoridae Griswold, Audisio & Ledford, 2012 is such a family and the last one that was described on newly collected specimens (Griswold et al 2012).…”

Taxonomic Revision and Cladistic Analysis of Psalistops Simon, 1889 and Trichopelma Simon, 1888 (Araneae, Barychelidae)

“…With respect to Barychelidae, the data from Hedin & Bond (2006) and Bond et al (2012) seemed to confirm the proximity of Barychelidae with Theraphosidae, uniting these two families in a monophyletic group, and leaving Paratropididae in an external position. This new result could be used to support the suggestion made by Raven (1994), as the Trichopelmatinae have always been considered a basal group within the Barychelidae, so it would not be too farfetched to imagine that this subfamily could potentially belong to Theraphosidae.…”

“…Some years later, Raven (1994) Some time later, Bond et al (2012) performed a new analysis including the same previously used characters, but this time adding a new molecular character: genes that codify nuclear proteins. This study included a small number of specimens, of which the same 2 genera of Barychelidae were once again used.…”

“…Moreover, Bond et al (2012) argued that the characters used to distinguish Theraphosidae and Barychelidae are ill-defined (e.g. shape of maxilla and number of labial and maxillary cuspules), some of which are shared by many other groups of mygalomorphs.…”

Venoms-based discovery of novel modulators of human neuronal α7 and α3* nicotinic acetylcholine receptors

“…In this study, venoms were derived from 59 mygalomorph spiders. The infraorder Mygalomorphae is comprised of 15 taxonomic families (Bond, 2012), of which two were considered here, namely Hexathelidae (1 species) and Theraphosidae (58 species).…”