Bembidion iridipenne Bousquet and Webster

Bousquet, Yves & Webster, Reginald, 2006, Descriptions of three new species of Bembidion Latreille (Coleoptera: Carabidae) occurring in Canada, Zootaxa 1297, pp. 23-35 : 29-30

Bembidion iridipenne Bousquet and Webster , sp. nov.

( Fig. 4 )

Etymology. The specific name derives from the Latin nouns iris, ­i or ­idis, f (rainbow) and penna, ­ ae, f (wing), referring to the iridescence on the elytra caused by the markedly striate microsculpture.

Type Material. Holotype (ɗ) in CNC labelled: "New Brunswick Sunbury Co. Lincoln 22 June 1997 R.P. Webster / Holotype Bembidion iridipenne Bousquet and Webster CNC No. 23456."

Paratypes from the following localities. Canada. NEW BRUNSWICK. Same data as holotype (1Ψ, CNC); York Co., 5.0 km SW jct. Hwy 101 & Charters Settelment Rd., 11/ 24.V.2001, R.P. Webster (2ɗɗ, 3ΨΨ, CNC). 7.5 km NW of St. Jacques near Truite R., 18.VI.1997, R.P. Webster (1Ψ, RPW). QUEBEC. Montmorency D.R., Parc des Laurentides, chemin de la Brulée, off Hwy 175 (760 m), 1.VII.2000, R.P. Webster (2ΨΨ, CNC). Lac Meach, Parc Gatineau, 27.VI.1971, 2.VIII.1971, 10.VIII.1971, C. Chantal (2ɗɗ, 3ΨΨ, CCC). Mt. Tremblant Park [= Parc du Mont­ Tremblant], 5.VI.1972, E.J. Kiteley (1ɗ, CNC). Lac Normand (Champlain), 29.VIII.1969, C. Chantal (1ɗ, CCC). United States of America. NEW HAMPSHIRE. Mt. Washington (5000–6000 ft.), 15.VII.1977, R. Davidson (1ɗ, CMNH). Concord airport, 1 mi. E Concord, Merrimack Co., 11.V.2001, 29.V.2001, D.S. Chandler (2ΨΨ, NHDE) [pine­oak barrens by beaver pond]. 5 mi. SE Rindge, 4.VI.83, P.J. Darlington (1Ψ, NHDE). Magalloway Mountain, 4 mi. SE First Connecticut Lake, Coos Co., 26.VII.1981, P.J. Darlington (1ɗ, 1Ψ, NHDE). 4 mi. NE Second Connecticut Lake, Coos Co., 24.VII.1981, P.J. Darlington (3ɗɗ, 2ΨΨ, NHDE) [wet boggy margin]. "Atkinson and Gilmanton Academy Grant" [about 12 km N of Errol, Coos Co.], 24.VI.1975 (2ɗɗ, NHDE). PENNSYLVANIA. 5 mi. NW Jamestown, Crawford Co., R. Davidson (1ɗ, CMNH). VERMONT. South Lincoln, 12.IV.1968, R.T. Bell (5ɗɗ, 1Ψ, CMNH). Mt. Mansfield, Nebraska Notch, 19.VIII.1975 (2ΨΨ, CMNH). Jonesville, Gillette Pond, 6.VII.1975, M. Langworthy (1Ψ, CMNH). Richmond, Gillette Pond, 5.VI.1973, J.& R. Bell (1ɗ, CMNH). VIRGINIA. Hightown, Highland Co., 4.VII.1980, A. Larochelle (9, CMNH, CNC).

Description. Color: Head and pronotum black with aeneous lustre; elytra yellowish with ± wide, irregular, median black band across the elytra and preapical black band not reaching suture and usually lateral edge on each side, interval 1 often ± infuscate over anterior half, anterior discal setigerous puncture usually surrounded by square, blackish spot; elytral epipleuron yellowish with area adjacent to metepisternum black; antennomere 1 brownish­black dorsally, yellowish underneath, antennomeres 2 and 3 reddish­black but paler at extremities and underneath, antennomeres 4–11 black; palpi yellowish­brown to reddish­brown; femora brownish­yellow, darker toward apex than at base, tibiae pale, yellowish with extremities ± infuscate, tarsomeres dark brownish­black to black. Microsculpture: Clypeus and frons (except mediad anterior supraorbital setae) with well impressed meshes, sculpticells convex; pronotum, including lateral depressions, with well impressed meshes, meshes slightly transverse on disc, isodiametric with sculpticells ± convex along lateral margins; elytra with striate microsculpture, microlines very fine but distinct at high magnification. Prothorax: Pronotum moderately constricted at base (WP/ WP b = 1.15 [1.13–1.18]; n = 20), with sides moderately widely rounded; lateral depressions relatively narrow for the group; basal edge moderately oblique toward posterior angles, with distinct sinuation behind level of basal impression; laterobasal carinae well developed, somewhat curved laterad toward anterior end. Elytra: Strial punctures relative fine for the group over anterior half of elytra, most punctures along stria 2 adjacent to anterior discal seta (ed3) about same size or slightly smaller than discal puncture. Metasternal sclerites: Anterior metasternal apophysis marginate laterally. Male genitalia: Median lobe as illustrated ( Fig. 4 ).

Apparent body length = 5.2–6.2 mm.

Geographical Distribution. This species ranges from New Brunswick and Quebec south to Virginia.

Wing Development. The wings are fully developed in this species as in other species of the subgenus Eupetedromus .

Habitat. Adults of this species have been collected in New Brunswick in open sunexposed areas under debris on bare muddy­clayish soil along large streams or along margins of beaver ponds. Adults were often observed running over the surface of bare patches of clay. In contrast, the externally similar B. incrematum occurs in shaded sites in New Brunswick, usually under alders along streams in leaf litter on muddy organic soils.

Note. This species belongs to the subgenus Eupetedromus Netolitzky. Adults are most similar externally to those of B. incrematum , a species exhibiting considerable structural variation over its distribution, but differ mainly by details of the pronotum: the sides are less rounded and the base less constricted, the basal edge is quite distinctly more oblique toward the posterior angle, the sculpticells convex along the lateral margin and the meshes evident also along the lateral depression. In addition most individuals of B. incrematum are darker than B. iridipenne , with a less developed yellowish pattern on the elytra.

Besides this new species, four North American species are currently included in the subgenus Eupetedromus : B. incrematum LeConte , B. immaturum Lindroth , B. graciliforme Hayward , and B. aratum LeConte (see Bousquet and Larochelle 1993: 139). The last named species, which ranges from southwestern United States to Honduras ( Erwin 1982: 480), is probably not closely related to the other species of Eupetedromus in our opinion. Its relationship to other groups of Bembidion is uncertain. On the other hand, B. variegatum Say , which is currently placed in the subgenus Notaphus Dejean ( Lindroth 1963) , should instead be included in the subgenus Eupetedromus based on structural similarities to members of Eupetedromus . The subgenus contains also seven species in the Palaearctic Region ( Marggi et al. 2003: 250), one of which ( B. incrematum ) is Holarctic in distribution.

Adults of Eupetedromus are mainly characterized in having a raised, shiny (without microsculpture) field around the anterior supraorbital setigerous puncture contrasting against the duller (with microsculpture) adjacent area, and the elytral microsculpture markedly striate, the microlines being indistinct or nearly so.

Figures

FIGURES 3 – 5. Median lobe of aedeagus (left lateral view). 3, B. nigrivestis (Rigaud, Quebec); 4, B. iridipenne (holotype); 5, B. nitidicolle (Rosefield, Saskatchewan). Scale bar = 0.2 mm.