James S. Ashe (1947-2005) and Stylianos Chatzimanolis
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taxon links Phylogenetic position of group is uncertain[down<--]Gymnusini Interpreting the tree
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phylogeny from Klimaszewski (1979)
Containing group: Gymnusini


Adults of the 10 described species of Gymnusa are mostly black (a few are reddish brown to dark brown) and range in length from 4.2-6.5 millimeters. They live in moss and detritus in swamps, bogs and in the marshy edges of lakes, streams and slowly moving rivers.

Gymnusa are known from northern Nearctic and Palearctic regions.

Klimaszewski (1979, 1982) revised the species of Gymnusa and provides species descriptions, keys for identification, illustrations of diagnostic characteristics, information about distribution and habitat, and a phylogenetic analysis.


Adults of Gymnusa are easily distinguished from their possible sister group Stylogymnusa by the presence in Gymnusa of:

(Klimaszewski 1979)

Ashe (2000) also provides detailed discussion of the structure of Gymnusa, and illustrations of mouthparts, within the context of a comparison with Stylogymnusa.

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From left to right, mandibles, maxilla and labium of Gymunsa variegata.

From left to right, detailed view of mandible, labrum and epipharynx.

Discussion of Phylogenetic Relationships

Klimaszewski (1979) provided the only available phylogenetic analysis for the species of Gymnusa based on morphological features of adults.


Ashe, J. S. 2000. Mouthpart structure of Stylogymnusa subantartica Hammond, 1975 (Coleoptera: Staphylinidae: Aleocharinae) with a reanalysis of the phylogenetic position of the genus. Zoological journal of the Linnean Society 130: 471-498.

Klimaszewski, J. 1979. A revision of the Gymnusini and Deinopsini of the World. Canada Agriculture monograph No. 25. 169 pp.

Klimaszeski, J. 1982. A revision of the Gymnusini and Deinopsini of the world. Sup. 2. Canadian Entomologist 114: 317-335.

Title Illustrations
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Scientific Name Gymnusa pseudovariagata
Location Canada (B. C.)
Size length 5.8 mm
Copyright © 1997 James S. Ashe (1947-2005)
About This Page

Development of this page made possible by National Science Foundation PEET grants DEB 95-21755 and DEB 99-78110 to James S. Ashe.

All images on this page copyright © 1997-2003 James S. Ashe.

James S. Ashe (1947-2005)
University of Kansas, Lawrence, Kansas, USA

Stylianos Chatzimanolis
University of Tennessee at Chattanooga

All Rights Reserved.

Citing this page:

Ashe (1947-2005), James S. and Stylianos Chatzimanolis. 2003. Gymnusa. Version 06 November 2003. in The Tree of Life Web Project,

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