Bembidion ozarkense Maddison & Hildebrandt

Hildebrandt, Drew A. & Maddison, David R., 2011, A new species of Bembidion Latrielle 1802 from the Ozarks, with a review of the North American species of subgenus Trichoplataphus Netolitzky 1914 (Coleoptera, Carabidae, Bembidiini), ZooKeys 147, pp. 261-275 : 267-271

Bembidion ozarkense Maddison & Hildebrandt sp. n. Fig. 3A4A, 4B5A6

Holotype.

Male (in OSAC), here designated, labeled "USA: Missouri: Carter Co., Current River at Van Buren, 135m, 36.9904°N, 91.0100°W, 24.iv.2005. DRM 05.015. D.R. Maddison" / "David R. Maddison DNA2552 DNA Voucher" [pale green paper] / "HOLOTYPE Bembidion ozarkense Maddison & Hildebrandt" [red paper]". Genitalia in glycerine vial with specimen; extracted DNA stored separately. GenBank accession numbers for DNA sequences of the holotype are JF800056 (28S) and JF800065 (COI).

Paratypes.

221 specimens as follows: USA: Missouri: Carter Co., Current River at Van Buren, 135m, 36.9904°N, 91.0100°W (88 specimens); Carter Co., Current River at Van Buren, 135m, 36. 9924°N, 91.0167°W (3); Carter Co., Current River at Van Buren, 135m, 36. 9911°N, 91.0133°W (3); Maries Co., Maries River near Argyle, 200m, 38. 2700°N, 92.0007°W (10); Reynolds Co., Clark National Forest. Sutton’s Bluff Campground (6); Washington Co., Irondale, Big River, 230m. 37.8302°N, 90.6895°W (16); Washington Co., Big River at route 21, 245m. 37.8121°N, 90.7723°W (4); Washington Co., Big River at route 21, 245m, 37.8132°N, 90.7734°W (1); Arkansas: Crawford Co., Lee Creek (1); Marion Co., Buffalo Point St.Pk. (42); Searcy Co., 5 mi. W. Big Flat. Big Creek (47). Male genitalia have been examined from at least one specimen from each paratype locality.

Paratypes of Bembidion ozarkense have been deposited in the CMNH, DAHC, OSAC and TAMU, and in the collections of The Natural History Museum, London (BMNH), the California Academy of Sciences (CAS), the Field Museum of Natural History (FMNH), the Museum of Comparative Zoology (MCZ), Muséum National d’Histoire Naturelle in Paris (MNHN), the University of Arizona (UAIC), the University of Alberta Strickland Museum (UASM), and the National Museum of Natural History, Smithsonian Institution (USNM).

Eighty-two specimens examined but not designated as paratypes are: USA: Missouri: Pulaski Co., Devil’s Elbow. Big Piney River. 10km E. Waynesville. 734 ft. 37 50 52.4 N 92 03 42.0 W (2); Arkansas: Marion Co., Buffalo Point S.P. (15); Searcy Co., 5.3 mi. W. Big Flat. Big Creek. (65). The Missouri specimens are omitted from the paratype series as there are no males whose genitalia could be examined; the Arkansas specimens are omitted as they are slightly damaged.

Type locality.

USA: Missouri: Carter Co., Current River at Van Buren, 135m, 36.9904°N, 91.0100°W. At the type locality (Fig. 2), adults of Bembidion ozarkense were co mmon on 24 April 2005; specimens occurred in company with Bembidion (Trichoplataphus) planum , Bembidion (Pseudoperyphus) antiquum Dejean, and Bembidion (Pseudoperyphus) chalceum Dejean.

Derivation of specific epithet.

Derived from the Ozark Plateau of Missouri and Arkansas, which encompasses the known range of this species.

Diagnosis.

Bembidion ozarkense males can be recognized among North American Trichoplataphus by the combination of epilobes of the mentum of normal size for a Bembidion (Fig. 3A), and aedeagus with the tip relatively thick and not abruptly bent downward (Fig. 4A and 4B).

This species is markedly similar to Bembidion rolandi in external form (Fig. 5), sharing with it normal mentum epilobes; narrow, flat body, with long antennae; the pronotal base notably constricted, hind angles right, with the lateral margins in front of the hind angle parallel and straight. We have not yet found any reliable external characters to separate the two species, although there are some traits by which they tend to differ. Specimens of Bembidion ozarkense tend to be slightly smaller (average SBL of males is 4.4 mm, of females 4.7 mm) than those of Bembidion rolandi (4.6 and 4.8 mm, respectively), but there is a broad range of overlap, as adults of both species range in length from 4.2 to 5.1 mm. Bembidion ozarkense tends to be darker than Bembidion rolandi , with less-rufous elytra, and with the posterior medial portion of the dorsal surface of the head darker, rarely with the rufous region of many Bembidion rolandi ; the second antennomere of Bembidion ozarkense is often infuscated centrally, whereas it is usually entirely pale rufous in Bembidion rolandi . However, while these tendencies are noticeable in larger series, there is enough overlap between species that they are of marginal use when comparing individual specimens.

The only morphological characteristic that we have found to reliably distinguish the two species is in the male aedeagus: the tip of Bembidion rolandi is thin, and abruptly bent downward (Fig. 4C and 4D; n=8), traits not found in Bembidion ozarkense (Fig. 4A and 4B; n=30). DNA sequence data can also be definitively used to identify the species; either COI or 28S rDNA will suffice.

However, the known distribution ranges are distinctly separate, and can be used in the absence of male genitalia or DNA sequences to identify specimens.

Geographic distribution.

The known specimens of this species are from the Ozark Plateau of Missouri and Arkansas (Fig. 6).