Tachyporinae Revisited: Phylogeny, Evolution, and Higher Classification Based on Morphology, with Recognition of a New Rove Beetle Subfamily (Coleoptera: Staphylinidae)

Simple Summary

The rove beetle subfamily Tachyporinae has been suggested to be polyphyletic for the last half century but there are no previous studies conducting phylogenetic analysis on this group specifically. Here, the most comprehensive tachyporine phylogeny is shown, which again rejects the monophyly of Tachyporinae and its largest tribe Tachyporini. A revised classification of Tachyporinae is proposed here based on observation of morphological characters and their phylogenetic analyses. This backbone phylogeny will be a framework for further evolutionary and ecological studies.

Abstract

Tachyporinae are one of the most phylogenetically problematic subfamilies in the mega-diverse rove beetle family Staphylinidae. Despite its high diversity and abundance in forest micro-environments, with over 1600 species worldwide, several previous studies had refuted the monophyly of this subfamily and its largest tribe, Tachyporini. Based on the results of morphology-based phylogenetic analyses and direct examination of specimens encompassing two extinct and all forty extant genera, a new suprageneric classification of Tachyporinae is proposed here, with the removal of the tribe Mycetoporini into a newly recognized subfamily Mycetoporinae stat. nov. Four tribes with two subtribes are arranged within Tachyporinae sensu nov.: Tachyporini sensu nov. (Tachyporina stat. nov., sensu nov. and Euconosomatina stat. rev., sensu nov.), Vatesini sensu nov., Deropini, and Tachinusini stat. rev., sensu nov. (= Megarthropsini syn. nov.). Urolitus syn. nov. is placed as a junior synonym of Sepedophilus. Additionally, Palporus stat. nov. is raised to a distinct genus from a subgenus of Tachyporus sensu. nov., and †Mesotachyporus syn. nov. is synonymized with the latter. Mycetoporine Bobitobus stat. rev. is resurrected from synonymy with Lordithon sensu nov., and considered as a valid genus. My revised classification provides a novel framework for taxonomic inventories and ecological studies of these groups.

New Data, Old Story: Molecular Data Illuminate the Tribal Relationships among Rove Beetles of the Subfamily Staphylininae (Coleoptera: Staphylinidae)

The megadiverse subfamily Staphylininae traditionally belonged to the best-defined rove beetle taxa, but the advent of molecular phylogenetics in the last decade has brought turbulent changes to the group's classification. Here, we reevaluate the internal relationships among the tribes of Staphylininae by implementing tree inference methods that suppress common sources of systematic error. In congruence with morphological data, and in contrast to some previous phylogenetic studies, we unambiguously recover Staphylininae and Paederinae as monophyletic in the traditional sense. We show that the recently proposed subfamily Platyprosopinae (Arrowinus and Platyprosopus) is a phylogenetic artefact and reinstate Arrowinus as a member of Arrowinini stat. res. and Platyprosopus as a member of Platyprosopini stat. res. We show that several recent changes to the internal classification of the subfamily are phylogenetically unjustified and systematically unnecessary. We, therefore, reestablish Platyprosopini, Staphylinini, and Xantholinini as tribes within Staphylininae (all stat. res.) and recognize Coomaniini as a tribe (stat. nov.) rather than subfamily. Consequently, the traditional ranks of the subtribes Acylophorina, Afroquediina, Amblyopinina, Antimerina, †Baltognathina, Cyrtoquediina, Erichsoniina, Hyptiomina, Indoquediina, Quediina, and Tanygnathinina are restored (all stat. res.). We review the current classification of Staphylininae and discuss sources of incongruence in multigene phylogenies.

Baltic amber Staphylinini (Coleoptera: Staphylinidae: Staphylininae): a rove beetle fauna on the eve of our modern climate

Cenozoic climate cooling, particularly during the Eocene, has drastically shaped modern biological assemblages through a shift from an equable greenhouse to a polarized icehouse. Present-day Europe lies in a highly seasonal and temperate area that strongly embodies this modern icehouse climate. Baltic amber provides a Middle Eocene snapshot of the European fauna before this large-scale change. Here, we focused on the rove beetle tribe Staphylinini and conducted a comprehensive phylogenetic study of all known Baltic amber fossils in a total-evidence phylogenetic framework that integrates morphology with molecular data from six gene fragments. Based on our well-resolved topology, we propose the following: †Baltognathina subtrib. nov., Afroquediina subtrib. nov., Antimerina subtrib. nov., †Baltognathus aenigmaticus gen. et sp. nov., †Eolophorus gen. nov., †Laevisaurus robustus and †Laevisaurus gracilis gen. et spp. nov., †Hemiquedius europaeus sp. nov. and †Bolitogyrus fragmentus sp. nov. †Quedius cretaceus is placed as junior synonym of †Cretoquedius infractus. The earliest definitive fossils of Quediina are reported herein from the Eocene. The Staphylinini fauna of Middle Eocene Europe combined thermophilic, freeze-intolerant lineages with freeze-tolerant, temperate lineages and, unlike most other staphylinid or beetle lineages, all have since become extinct in the Palaearctic region.