Brachygluta (Brachygluta) cochimi 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 : 69-71

25. Brachygluta (Brachygluta) cochimi Bückle , sp. n.

( Figs 30 , 42 C)

Material examined, 6 specimens. HOLOTYPE male: MEXICO: Baja California: // MEXICO: Baja Calif. Norte, Isla San Lorenzo, SW cyn. wash, VII-27/28 -86, Rolf L. Aalbu col., BL/ [red label] HOLOTYPE Brachygluta cochimi Bückle // ( CSCA). PARATYPES, 5 males: eutopotypical ( CSCA, 3; DSCC, 2). A female from Baja California, Bahía de los Ángeles, VII-19-1978, D.W. Anderson ( UCBC) compares well with the type series.

Description. BODY: Length 2.00– 2.16 mm; orange-brown with elytra sometimes lighter; head and pronotum with setae short, curved and suberect, over rest of body setae appearing denser, longer and decumbent. Head: surface smooth, shining, punctures indistinct. Antennomeres III–VI longer than wide, VII as long as wide, VIII transverse, IX as long as wide, X slightly wider than long, VIII about two-thirds width of IX ( Fig. 30 C). Setose area of median vertexal fovea as large as those of lateral foveae. Pronotum: surface smooth, shining, punctures indistinct. Setose area of median antebasal fovea about two-thirds width of lateral antebasal foveae. Elytra: with microreticulation, punctures varying from indistinct to small and distinct, discal stria extending to about four-fifths of elytral length. Abdomen: disc with small, distinct punctures, opaque in apical half due to distinct microreticulation, basal half shining; basal striae of tergite 1 short, one-fifth to one-fourth paratergite length, divergent, separated at base by about one-half tergite width; setose comb at base between basal striae distinct.

MALE: Antennae and trochanters lacking modifications, simple. Metaventrite with circular patch of dense short silvery setae extending from between metacoxae to middle. Tergite 1 distinctly microreticulate in apical half, apical margin convex; in lateral view slightly protruding out over tergite 2. Tergite 2 with weak slightly arcuate carina in middle third ventral to apex of tergite 1, base impressed anterior to carina, shallow longitudinal impression posterior to carina extending to tergite apex, impression shining but smoothly roughened ( Fig. 30 A); tergites 3–4 with punctures sparse and distinct; tergite 4 with lateral margins protruding, bluntly tuberculate, with tuft of long setae at apices, tergite apex nearly subtruncate; tergite 5 with long setae directed posteromedially from lateral thirds ( Figs 30 A–B); in lateral view tergite 1 rising to apex, projecting out above base of 2, 2–4 confluently curved. Ventrites broadly rounded. Metatibiae thin, narrow at base, gradually widened to near apex, mesal margin of apical fifth with brush present ( Fig. 30 D). Aedeagus 0.34 mm long; dorsal plate triangular, margins evenly converging to bluntly rounded point; parameres rounded at apex, three thick setae on lateral margin at angle of preapical constriction; thickened hyaline seta on mesal margin, longer than preapical setae, thickened to middle, with acute apex; internal sac with two curved large spines ( Fig. 30 E).

FEMALE: [one female tentatively placed as this species] Lacking modifications of abdomen, otherwise similar to male; metaventrite sparsely and evenly setose, setae similar to others on abdomen.

Collecting data. The type series was taken at blacklight in July on a desert island.

Distribution ( Fig. 42 C). Found on the east coast of Baja California near the middle of the Gulf of California.

Comments. This species is unusual in having tergites 4–5 modified. Tergite 4 has a bluntly protruding and apically setose tubercle at each lateral margin. Tergite 5 has long setae on the lateral portions of this sclerite directed posteromedially. The gently rounded apical margin of tergite 1, and the impression of tergite 2 defined posteriorly by a slight carina further serve to identify this species. It shares with B. seri a relatively long tergite 2, and its collection location from an island in the middle of the Gulf of California, but B. seri has tergites 1 and 2 subequal in length, and lacks the modifications of tergites 2, 4, and 5.

Etymology. Named for an American indigenous group of central Baja California where this species was found.

Figures

FIGURE 30. Brachygluta cochimi Bückle (Mexico, Baja California, paratype). A: Abdomen, dorsal view. B: Abdomen, caudal view. C: Right antenna. D: Left metatibia, posterior view. E: Aedeagus.

FIGURE 42. Distribution map of Brachygluta seri species-group and Brachygluta mormon species-group. A: Brachygluta chisos Sabella. B: Brachygluta klamath Bückle. C: Brachygluta cochimi Bückle. D: Brachygluta seri Chandler.