Radiation of staphylinid beetles in the Southern Appalachians
Goals: To revise the groups of staphylinid beetles represented in the Southern Appalachians by clusters of endemic species. To analyze the area cladograms based on different staphylinid genera. To develop a model of dispersal and speciation in the Southern Appalachians under varying climatic conditions.
The Southern Appalachians (Map 1) are represented by a large group of mountains (up to 2000 m high) isolated from each other by valleys of different depth and breadth. Many isolated mountains are inhabited by numerous endemic species, which places the Southern Appalachians among the regions with the highest biodiversity in the Nearctic region. Salamanders are probably the best known example. Great Smoky Mountains National Park which occupies the territory of about 800 square miles supports 30 species of salamanders and has been called the "Salamander Capital of the World". Another example is the carabid genus Trechus Claireville, 1806 represented in the Southern Appalachians by 50 species and subspecies (Barr 1962, 1969, 1979, 1985; Kane et al. 1990).
In staphylinid beetles the following genera are known to be represented in Southern Appalachians by clusters of endemic species:
Subfamily Aleocharinae:
- Geostiba Thomson, 1858 (Gusarov 2002)
- Ocyustiba Lohse & Smetana, 1988 (Lohse & Smetana 1988; Pace 1997; Gusarov, unpublished)
- Leptusa Kraatz, 1856 (Pace 1989; Gusarov, unpublished)
- Myllaena Erichson, 1837 (Pace 1997)
Subfamily Tachyporinae:
- Ischnosoma Stephens, 1829 (Campbell 1991; Gusarov, unpublished)
Subfamily Paederinae:
- Lathrobium Gravenhorst, 1802 (Gusarov, unpublished)
Steninae:
- Stenus Latreille, 1796 (Benick 1928; Cornell & Puthz 1997; Gusarov, unpublished)
Dasycerinae:
- Dasycerus Brongniart 1800 (Löbl & Calame 1996; Gusarov, unpublished)
The genus Geostiba which has just been revised (Gusarov 2002) is represented in the Southern Appalachians by 12 species (Map 2). A discussion of their distribution can be found in Gusarov (2002).
In Stenus two species groups (one in subgenus Parastenus, another in Hypostenus) are represented in the Southern Appalachians by clusters of endemic wingless species. My preliminary results suggest that at least 8 species of Parastenus occur in this area (Map 3).
In Ischnosoma the Suteri group of species is represented in the Southern Appalachians by at least 3 species. One species (I. lecontei Campbell, 1991) is more widepread, decends as low as 800 m and has been recorded from North Carolina, South Carolina, Tennessee, Georgia, Kentucky and Virginia. Comparison of populations from different localities did not reveal any geographical variability in external characters or male genitalia. Compared to I. lecontei, two other species of this group (I. suteri Campbell, 1991 and I. n. sp. 1; not distinguished by Campbell (1991)) are more advanced in their adaptations to cryptic microhabitats. Their distribution is shown in Map 4. The female from Shenandoah National Park, Virginia, mentioned by Campbell (1991: 137) may belong to yet another species of this group.
In a recent revision of Dasycerus (Löbl & Calame 1996) three species have been reported from the Southern Appalachians. In two species (D. bicolor Wheeler & McHugh 1994 and D. concolor Löbl & Calame, 1996) the eyes are large, and in one (D. carolinensis Horn, 1882) very small. My examination of the specimens from different populations of the latter species demonstrated that it is in fact a group of many species (Carolinensis species group). At least 9 species were found in examined material.
I am currently preparing for publication revisions of Appalachian Parastenus, Ischnosoma, and Dasycerus, as well as revising the Appalachian species of some other staphylinid genera.
References.
Barr, T.C. (1962) The genus Trechus (Coleoptera: Carabidae: Trechini) in the southern Appalachians. The Coleopterists Bulletin, 16, 65-92.
Barr, T.C. (1969) Evolution of the (Coleoptera) Carabidae in the Southern Appalachians. In: Holt, P.C., Hoffman, R.L. & Hart, C.W. (Eds.), The Distributional History of the Biota of the Southern Appalachians. Part I: Invertebrates. Research Division Monograph. Blacksburg: Virginia Polytechnic Institute, pp. 67-92.
Barr, T.C. (1979) Revision of Appalachian Trechus (Coleoptera: Carabidae). Brimleyana, 2, 29-75.
Barr, T.C. (1985) Pattern and process in speciation of trechine beetles in eastern North America (Coleoptera: Carabidae: Trechinae). In: Ball, G.E. (Ed.), Taxonomy, Phylogeny and Zoogeography of Beetles and Ants. Dordrecht: Dr W.Junk Publishers, pp. 350-407.
Benick, L. (1928) Amerikanische Steninen (Col., Staph.). Wiener Entomologische Zeitung, 45(2-3), 33-52.
Campbell, J.M. (1991) A revision of the genera Mycetoporus Mannerheim and Ischnosoma Stephens (Coleoptera: Staphylinidae: Tachyporinae) of North and Central America. Memoirs of the Entomological Society of Canada, 156, 1-169.
Cornell, J.F. & Puthz, V. (1997) Two new North American Stenus (Parastenus) species from the Appalachians (Insecta: Coleoptera, Staphylinidae: Steninae). Philippia, 8(2), 131-136.
Gusarov, V.I. (2002) A revision of Nearctic species of the genus Geostiba Thomson, 1858 (Coleoptera: Staphylinidae: Aleocharinae). Zootaxa, 81, 1-88 [Accessible free of charge at <http://www.mapress.com/zootaxa/2002f/zt00081.pdf>].
Kane, T.C., Barr, T.C. & Stratton, G.E. (1990) Genetic Patterns and Population Structure in Appalachian Trechus of the vandykei Group (Coleoptera: Carabidae). Brimleyana, 16, 133-150.
Löbl, I. & Calame, F.G. (1996) Taxonomy and phylogeny of the Dasycerinae (Coleoptera: Staphylinidae). Journal of Natural History, 30, 247-291.
Lohse, G.A. & Smetana, A. (1988) A new genus and a new species of Aleocharinae from the Appalachian Mountains of North Carolina (Coleoptera: Staphylinidae). Coleopterists Bulletin, 42(3), 265-268.
Pace, R. (1989) Monografia del genere Leptusa Kraatz (Coleoptera, Staphylinidae). Memorie del Museo Civico di Storia Naturale di Verona (II Serie), Sezione Scienze della Vita (A: Biologica), 8, 1-307.
Pace, R. (1997) Aleocharinae attere del North Carolina, Tennessee e Oregon (Coleoptera, Staphylinidae). Bollettino del Museo Regionale di Scienze Naturali, Torino, 15(1), 101-110.
Last updated: April 16, 2009