DNA barcode sheds light on species boundaries in the common morphologically variable rove beetle Quedius umbrinus-complex that puzzled taxonomists for more than a century (Coleoptera, Staphylinidae)

Abstract

In the course of a long taxonomic history, Quedius umbrinus Erichson, a common West Palaearctic rove beetle, was gradually split into a dozen species before all of them, except Q. sigwalti Coiffait from Crete, were lumped back into a single species again. All these shifts were based on the intuitive evaluation of morphological variation only. We sequenced the barcoding fragment of the CO1 gene across specimens of Q. umbrinus-complex broadly covering its geographic range and performed several DNA barcode species delimitation analyses on this dataset: tree-based Bayesian inference and Maximum likelihood, as well as tree-independent character-based (PTP, GMYC) and distance-based (ABGD). Molecular clades were largely congruent among all analyses and revealed four candidate species lineages. Of them, only Q. sigwalti is easy to distinguish by morphology alone. Morphological differences between other candidate species are present, but they are weak and do not hold for all specimens. To reflect new data in the classification we reinstated Q. pseudoumbrinus Lohse (stat. res.) as a species even though it is not always distinct from Q. umbrinus Er. (stat. rev.) morphologically. Also, we described a new species Q. volkeri (sp. nov.) from the north-western Caucasus. Finally, we placed Q. angaricus Coiffat in synonymy with Q. pseudoumbrinus Lohse (syn. nov.).

http://www.zoobank.org/urn:lsid:zoobank.org:act:B6E2ED11-2029-48E7-975F-060D9DA61648

Key words:

• Staphylininae
• Quediini
• phylogenetics
• CO1
• morphology
• West Palaearctic

Acknowledgements

The molecular work was performed in the laboratory of the Institute of Environmental and Agricultural Biology (X-BIO), University of Tyumen (Tyumen, Russia) and the research centre “Chromas” Core Facility of St. Petersburg State University (St. Petersburg, Russia). We would like to express our gratitude to the responsive employees of both laboratories kindly assisting in the process of obtaining molecular data, especially the former head of Chromas Core Facility of St. Petersburg State University Alsu Saifitdinova. Thanks to all the curators mentioned in the Materials and methods section and other colleagues who shared with us necessary specimens from the respective museums and collections. We are grateful to all colleagues who participated and helped in the organization of our expeditions (mostly mentioned as collectors in Supplementary Material Table S2). Igor Orlov (University of Tyumen, Russia) is thanked for helping to obtain photos for Figures 1–10. Two anonymous reviewers are greatly acknowledged for their critical comments and suggestions that led to a significant improvement of the manuscript. This research was supported by the Russian Science Foundation (RSF) grant no. 20-74-00130.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplementary material

Supplementary material for this article can be accessed here: https://dx.doi.org/10.1080/14772000.2021.1943559.

 

Associate Editor: Dimitar Dimitrov