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Coleoptera of Great Smoky Mountains National Park Species Pages

Family Histeridae

            Tribe Histerini

 Margarinotus (Ptomister) immunis (LeConte)

Description and Taxonomy

Length 5..5-7.5 mm. The genus belongs to the tribe Histerini, which is characterized by the presence of an expanded prosternal lobe, free labrum, antennal cavities situated under the anterior angles of pronotum, dentate protibiae with straight protarsal furrow, antennal club with annuli not V-shaped, mesosternum without median projection and prosternal base without emargination (Kryzhanovskij & Reichardt 1976, Kovarik & Caterino 2000).  Five or six genera of Histerini are known in N. America (Kovarik & Caterino 2000, Bousquet & Lapalante 2006), and three are present in GSMNP. Margarinotus is an externally diverse genus diagnosed primarily by several characters of the male genitalia.  However, most species (all in the East and GSMNP) may be recognized by the emarginate outline of the anterior margin of the mesosternum and complete inner subhumeral striae on elytra. Twenty-nine described species in the genus are known in N. America, seven of which are found in the GSMNP. This species may be diagnosed by the complete marginal stria of the pronotum, the presence of two lateral pronotal striae, absence of basal fragments of the 5th dorsal striae and a subapical depression on the elytron, sparse puncturation of the propygydium and pygidium and interrupted lateral metasternal stria. Sparser puncturation of pygidia and the absence of a subapical elytral depression allows separation of this species from its most similar congener, M. egregius.

Life History

 The natural history of the species is poorly known. It has been collected in forested areas, on carrion and in forest litter (Bousquet & Lapalante 2006).  It was collected in GSMNP once at 580 m elevation.

Distribution

 Widespread in eastern N America  from Manitoba and Nova Scotia to Florida (Bousquet & Lapalante 2006).

Conservation Concerns

Not under threat.

Locality records in GSMNP.

Acknowledgements

Development of these pages was supported by grants from Discover Life in America and the National Science Foundation (DEB-0516311).

References

Bousquet, Y. and S. Laplante. 2006.  Coleoptera Histeridae. The insects and arachnids of Canada. Part 24. NRC Research press, Ottawa. 485 pp.

Kovarik, P.W. and M. S. Caterino.  2000. Histeridae. Pp. 212-227 in: Arnett, R. H. and M. C. Thomas (eds.) American beetles. Vol. 1. CRC Press, Boca Raton  - London - New York - Washington.

Kryzhanovskij, O. L. and A. N. Reichardt. 1976. Histeroidea. fauna of the USSR. Vol. V (4). Nauka: Moscow - Leneingrad. 433 pp.

 

Posted 13 August 2007, A. K. Tishechkin, Louisiana State Arthropod Museum.

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