Brachygluta (Brachygluta) wickhami Bückle, 2015

Chandler, Donald S., Sabella, Giorgio & Bückle, Christoph, 2015, A revision of the Nearctic species of Brachygluta Thomson, 1859 (Coleoptera: Staphylinidae: Pselaphinae), Zootaxa 3928 (1), pp. 1-91 : 62-64

21. Brachygluta (Brachygluta) wickhami Bückle , sp. n.

( Figs 26 , 41 B)

Material examined, 70 specimens. HOLOTYPE male: USA: Iowa: Johnson Co.: // Iowa City, Wickham, V-22- 98 / [yellow circle] 277./ F.C. Bowditch Coll./ [red-bordered label] Brachygluta arguta Csy. / [red label] HOLOTYPE Brachygluta wickhami Bückle // ( MCZC). PARATYPES, 64: USA: District of Columbia: “D.C.” ( CMNH, 1). Illinois: DuPage Co.: Argonne Natl. Lab., VI-13-1967 ( FMNH, 1M), VIII-1-1967 ( FMNH, 1M), W. Suter, at light. Iowa: Johnson Co.: Iowa City, IV-3-1898 ( FMNH, 2M), IV-7-1900 ( DSCC, 2; FMNH, 2M, 1F; CUIC, 1), IV-16-1899 ( FMNH, 2M, 4F), V-15-1898 ( DSCC, 1M; FMNH, 1M, 1F; MCZC, 1), V-22-1898 ( AMNH, 2; UNHC, 1F; MCZC, H.C. Fall Collection, 2M, 1F; FMNH, 7M, 4F; MCZC, 2M, 6F; SEMC, 1F), VI-11-1898 ( CUIC, 1; MCZC, H.C. Fall Collection, 1; FMNH, 1M; MCZC, 1F), Wickham; VI-16-1898, W. ( MCZC, 1M); specimen without collector ( FMNH, 1M). Pennsylvania: Bedford Co.: Shellburg, VIII-16 ( CMNH, 6M; DSCC, 1M). Jefferson Co.: Cook State Forest, 1.2 mi N Cooksburg, Troutman Run, VI-6-1997, D.S. Chandler, leaf litter along stream ( DSCC, 1M). West Virginia: Grant Co.: Hiser, V-25-1994, S.M. Clark ( WVDA, 1). Mason Co.: McClintic Wildlife station, VII-26-1986, M.C. Thomas, UV trap ( WVDA, 1). Morgan Co.: Widmeyer Wildlife Management Area, VIII-21-1997, S.M. Clark ( DSCC, 1).

Females that lack associated males collected on the same day are: Iowa: Johnson Co.: Iowa City, IV-10-1898 ( FMNH, 1F; MCZC, 2F), IV-24-1898 ( DSCC, 1F; FMNH, 1F; SEMC, 1F). These are not designated as paratypes, but are almost certainly members of this species.

Description. BODY: Length 1.72–2.00 mm; brown; setae on head and pronotum short, curved and suberect, over rest of body longer and decumbent. Head: surface smooth, shining, punctures indistinct. Antennomere III–VI longer than wide, VII as long as wide, VIII–X transverse, VIII about two-thirds width of IX. Setose area of median vertexal fovea as wide as those of lateral foveae. Pronotum: surface smooth, shining, punctures minute. Setose area of median antebasal fovea slightly smaller than those of lateral antebasal foveae. Elytra: surface smooth to with faint microreticulation, punctures indistinct, discal stria extending to about four-fifths of elytral length. Abdomen: basal striae of tergite 1 long, divergent, close to two-thirds length of paratergite in male, about half length of paratergite in female, separated at base by about two-fifths tergite width, with distinct brush of spaced setae between striae in male, brush indistinct with only sparse setae present in female; disc lightly punctate.

MALE: Antennae and trochanters not modified. Metaventrite with transverse band of dense setae between metacoxae. Only tergites 1–2 visible in dorsal view, tergite 1 twice as long as 2; tergite 1 with disc smoothy and shallowly convex, apex slightly emarginate at middle, with row of appressed golden setae forming elongate flattened lamina, lamina shallowly emarginate at apex and directly posteroventrally; tergite 2 with semicircular impression at middle extending from base to or near apex, narrow median strip glabrous, lateral portions of impression with setae suberect, directed obliquely medially, denser and more elongate than on lateral portions of tergite; lateral portion of tergite 2 with flattened or lightly impressed coarsely punctate area, setae in this area much shorter and appressed; apex of tergite straight posterior to impression; tergites 3–5 evenly convex, not modified; in lateral view tergite 1 rising to deflexed apex, 2 directed posteriorly, 2–4 curved confluently, with distinct gap between base of 2 and apex of 1. Abdominal ventrites broadly convex. Metatibiae thin, narrow at base, gradually widened to near apex, mesal margin of apical fourth with brush present. Aedeagus 0.36 long mm; with parameres curved laterally in apical portion, with distinct preapical constriction, with three aciculate preapical setae on lateral margin, with narrow, flat, hyaline seta on inner margin near apex; dorsal plate usually slightly asymmetric, roughly triangular to narrowing to acute apex, apex curving slightly to either side; internal sac with two large isolated and slightly curved spines ( Figs 26 A–C).

FEMALE: Metaventrite convex, setae sparse over disc, but denser at middle than on lateral portions of metaventrite. Abdominal tergites evenly convex; ventrites broadly convex. Metatibiae similar to those of male.

Collecting data. There are few habitat/collection records for this species, with one specimen being sifted from leaf litter by a stream, and three specimens were collected at light. Taken from April to August, with most of the specimens collected in April and May.

Distribution ( Fig. 41 B). A species of the Midwestern and Northeastern states, and found in two general areas at this time: Iowa and Illinois, and from Pennsylvania to West Virginia plus the District of Columbia. Most of the specimens were taken in the Iowa City area by H.F. Wickham over a three year period, where 57 of the 71 specimens examined were collected.

Comments. This species is similar to B. arguta , and only the males can be separated by using subtle differences in the form of tergite 2, and by examining the male genitalia. The median impression of tergite 2 tends to reach the apex of the tergite, and the setae on the inner margins of the impression are denser and longer. The median lobe of the genitalia is shorter and broader, and the internal sac lacks a multi-dentate tooth.

Etymology. Named for H.F. Wickham, who collected most of the type series, and whose collaboration with Emil Brendel produced one of the most important treatments of the North American Pselaphinae .

Figures

FIGURE 26. Brachygluta wickhami Bückle. A: Aedeagus (Pennsylvania, Bedford Co., paratype). B: Aedeagus (Iowa, Johnson Co., paratype). C: Aedeagus, internal sac (District of Columbia, paratype).

FIGURE 41. Distribution map of Brachygluta arguta species-group. A: Brachygluta arguta (Casey). B: Brachygluta wickhami Bückle. C: Brachygluta terebrata (Casey) (excluding Canada, Saskatchewan). D: Brachygluta elegans (Brendel) (Red dot: material examined, green dot: only state on label).