Brachygluta (Brachygluta) intermedia (Brendel, 1866)

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 : 28-31

8. Brachygluta (Brachygluta) intermedia (Brendel, 1866)

( Figs 9–10 , 36 C)

Bryaxis intermedia Brendel, 1866b: 191 (as variety). Type localities: District of Columbia and Tennessee. Type depository ANSP, Lectotype male // D.C./ Brend/ Horn Coll H1921/ Lectotype desg. Moxey 1962 / B. intermedia Brend. / [red label] TYPE #8299 Bryaxis intermedia Brendel Carl Farr Moxey 29.VI.1962 //. Brendel 1866b: 194 (female characters). LeConte 1880: 182 (key). Moxey 1962: 98 (lectotype designation).

Bryaxis (Bryaxis) intermedia: Brendel & Wickham 1890: 267 (key), 279 (redescription), plate VIII, fig. 52.

Brachygluta intermedia: Raffray 1904: 225 ; 1908: 231; 1911: 94. Leng 1920: 130. Bowman 1934: 83 (Group I, key), 84. Moxey 1962: 101. Chandler 1994: 50 (lectotype designation); 1997: 55. Downie & Arnett 1996: 581. Poole & Gentili 1996: 380.

Bryaxis labyrinthea Casey, 1894: 477 . Type locality: New York. Type depository: USNM, male holotype. //N.Y./ Casey bequest 1925/ TYPE USNM 38689/ labyrinthea //. NEW SYNONYMY.

Brachygluta labyrinthea: Raffray 1904: 225 ; 1908: 231; 1911: 94. Leng 1920: 130. Bowman 1934: 83 (Group I, key), 84. Downie & Arnett 1996: 580. Poole & Gentili 1996: 380. Chandler 1997: 56.

Material examined, 23 specimens. USA: Delaware: Only state on label: “Del.”, IX-1938, C. Cottam ( USNM, 1). District of Columbia: D.C. ( ANSP, 1, Lectotype; CMNH, 3; MCZC, 1). Maryland: Montgomery Co.: Plummers Island, V-11-1905, Barber & Schwarz ( USNM, 1). Somerset Co.: Marion, VII-29-1978, E.J. Ford, Jr., UV light ( DSCC, 1). New York: Westchester Co.: Peekskill, V-17-1890 ( USNM, Casey Collection, 1); Peekskill ( FMNH, 3). Only state on label: “N.Y.” ( USNM, holotype B. labyrinthea ; SEMC, 3); “N.Y.”, V ( FMNH, 2). North Carolina: Mecklenburg Co.: Mint Hill, IV-1 /7-1994, J. Bryan & J. Cornell, UV light ( DSCC, 1). Wake Co.: Raleigh, IV-12-1953, D.M. Weisman ( NCSU, 1M). Tennessee: Only state on label: “Ten.” ( CMNH, 1, Paralectotype). Virginia: Hampton City: Fort Monroe, V-30, Hubbard & Schwarz ( USNM, 1). Spotsylvania Co.: Fredricksburg, VII-6-1891, W.D. Richardson ( USNM, 1).

Description. BODY: Length 2.28–2.40 mm; orange to orange-brown; setae appressed or nearly so. Head: surface smooth, shining, punctures minute. Setose area of median vertexal fovea one-third larger than lateral foveae. Antennomeres III–VII longer than wide, VIII–IX slightly transverse, X slightly longer than wide, VIIItwo-thirds width of IX ( Fig. 10 B). Pronotum: surface smooth, shining, punctures indistinct. Median antebasal fovea about two-thirds width lateral antebasal foveae. Elytra: surface varying from indistinctly punctate and faintly microreticulate to punctures faint on roughened and microreticulate surface, discal stria extending to about fourfifths of elytral length. Abdomen: tergite 1 with surface lightly punctate; males with basal striae of tergite 1 extending about four-fifths length of paratergite (females unknown), basal striae separated by about two-fifths basal width of tergite 1, with long sparse setal brush between striae.

MALE: Antennae and trochanters lacking modifications, simple. Metaventrite transversely impressed as broad oval from between metacoxae to near mesocoxae, impression covered with dense short setae. In dorsal view only tergites 1–2 visible ( Figs 9 A, 10A), 2 slightly longer; 1 with basal abdominal carinae distinct, extending posteriorly to prominent rounded preapical mounds whose posterior margins protrude over tergite 2, apical margin of 1 slightly concave between these projections, this margin darkly carinate and briefly toothed ventral to apices of projections, carina with apical row of short setae, lateral margin with oblique dense row of setae extending medially to tergite 2, posterolateral portion of projections convexly impressed and densely setose; tergite 2 with paratergites visible, with broadly rounded median ridge originating between projections of tergite 1, tergite broadening apically to broadly rounded lateral humps at apical margin, apical margin between humps gently concave, lateral margins of median ridge with dense long setae directly laterally over deep impressions lateral to ridge, some setae reach lateral margins of tergite, two divergent black tubercles originate at base of tergite 2 ventral to median carinate apex of 1, typically not visible except in posterior view ( Fig. 9 C); tergite 3 broadly truncate at apex, lateral portions dorsally impressed and densely setose; tergites 4–5 simple, convex; in lateral view tergite 1 strongly projecting dorsally at apex, posterior margin vertical and dropping to relatively distant flat disc of 2 ( Fig. 9 B). Abdominal ventrites all broadly rounded. Metatibiae broad near base and evenly wide through length, with thick setal brush on inner margin where metatibiae curves slightly medially at apical sixth ( Figs 10 C–D). Aedeagus 0.40 mm long; with dorsal plate triangular, acutely pointed at apex; parameres broad to abrupt preapical constriction, with three thick setae at point of constriction on lateral margin, mesal margin at constriction with broad, flattened, hyaline seta pointed at apex; internal sac with three large slightly curved spines ( Figs 9 D, 10E).

FEMALE: Female not examined. Brendel (1866b: 194) discusses “the supposed form” of the female, and states that it is closer to B. dentata , is more convex than B. floridana , and that the frontal groove (fovea?) is smaller and distinct. Females of B. dentata have very short basal discal carinae on tergite 1, while the males of B. intermedia have long and prominent basal discal carinae. This may be a male sexual feature, but until the sexes are associated, speculation is fruitless.

Collecting data. The only collecting data indicate that they will fly to ultraviolet light, and that adults are active from April through September.

Distribution ( Fig. 36 C). This species ranges from New York to North Carolina. The majority of records are from Atlantic coastal marsh areas, but those from central North Carolina and Tennessee indicate that this species may occur (rarely) well inland from the coast.

Comments. Brendel (1895: 184) believed that Bryaxis labyrinthea was at most barely a variety of B. intermedia , and in our opinion the male characters are identical. Bryaxis labyrinthea Casey, 1894 is here placed as a junior synonym of Bryaxis intermedia Brendel, 1866 . This species is closest to B. floridana in having only tergites 1–2 visible in dorsal view and tergite 1 with dorsally projecting lobes. The two are easily separated by B. intermedia having tergite 2 as long as 1 and not prominently bilobed at the apex, while B. floridana has tergite 2 slightly more than half the length of 1, and the apex has two prominent lateral lobes.

Figures

FIGURE 9. Brachygluta intermedia (Brendel). A: Abdomen, dorsal view (North Carolina, Mecklenburg Co.). B: Abdomen, lateral view (North Carolina, Mecklenburg Co.). C: Abdomen, caudal view (North Carolina, Mecklenburg Co.). D: Aedeagus (Maryland, Somerset Co.).

FIGURE 10. Brachygluta intermedia (Brendel). A: Abdomen, dorsal view (holotype of B. labyrinthea (Casey )). B: Right antenna (North Carolina, Mecklenburg Co.). C: Left metatibia, anterior view (North Carolina, Mecklenburg Co.). D: Left metatibia, anterior view (holotype of B. labyrinthea (Casey). E: Aedeagus (holotype of B. labyrinthea (Casey).

FIGURE 36. Distribution map of Brachygluta abdominalis species-group. A: Brachygluta abdominalis (Aubé). B: Brachygluta floridana (Brendel). C: Brachygluta intermedia (Brendel). D: Brachygluta ulkei (Brendel). (Red dot: material examined, green dot: only state on label and / or literature records).