Brachygluta (Brachygluta) mayo Sabella

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 : 75

28. Brachygluta (Brachygluta) mayo Sabella , sp. nov.

( Figs 33 , 43 C)

Material examined, 20 specimens. HOLOTYPE male: MEXICO: Sinaloa: // MEXICO: Sinaloa, 2 mi. E San Blas, VII-5-82, F. Andrews, Blacklight/ [red label] HOLOTYPE Brachygluta mayo Sabella // ( CSCA). PARATYPES, 19 males: MEXICO: Baja California Sur: Isla Magdalena, Howlands Lagoon, VII-6-1983, D. Faulkner ( CSCA, 1). Nayarit: San Blas, VI-15-55, B. Malkin ( UCDC, 1). Sinaloa: eutopotypical ( CSCA, 6; DSCC, 2); same data but Fred G. Andrews, coll. blacklight ( CSCA, 4; DSCC, 1). Culiacán, 19 mi. S., VI-22-63, J. Doyen Collector ( UCBC, 1). Sonora: San Carlos Bay, VIII-10-60, P.H. Arnaud, Jr., E.S. Ross, D.C. Rentz ( CASC, 2).

Description. BODY: Length 1.88–2.00 mm. Body orange-brown to brown, when brown often with elytra orange-brown; head and pronotum with setae short, curved and suberect, on rest of body longer and decumbent. Head: surface smooth, shining, punctures small, distinct. Antennomeres III–VII longer than wide, VIII slightly transverse, IX about as wide as long, X about as long as wide, VIII about two-thirds width of IX ( Fig. 33 C). Setose area of median vertexal fovea as large as those of lateral foveae. Pronotum: surface smooth, shining, punctures small, distinct. Setose of median antebasal fovea about two-thirds width of lateral antebasal foveae. Elytra: microsculpture mostly lacking, surface smooth, shining, punctures small and distinct, discal stria extending to about four-fifths of elytral length. Abdomen: disc smooth, shining, punctures distinct; basal discal striae of tergite 1 at most one-fourth paratergite length, straight, separated at base by greater than one-half tergite width; setose brush between bases of striae long, setae sparse.

MALE: Antennae and trochanters unmodified, simple. Metaventrite covered with long setae that are densest in arcuate area curving anteriorly from between metacoxae. Tergite 1 with small shallow emargination at middle of apex to apex appearing flattened; tergite 2 with arcuate impression extending from base to near apex, impression about three-fifths width of tergite, with line of anteriorly directed thick setae in impression positioned near lateral margins in impression, rounded carinate tubercle projecting postero-dorsally ventral to apex of tergite 1, seldom visible in dorsal view ( Figs 33 A–B); in lateral view tergite 1 slightly protruding over base of tergite 2; in lateral view with tergite 1 disc slightly rising to deflexed apex, distinct drop from apex to flat tergite 2. Abdominal ventrites broadly rounded. Metatibiae thin, narrow at base, gradually widened to near apex, mesal margin of apical third with brush present ( Fig. 33 D). Aedeagus 0.44 mm long; with apex of dorsal plate broadly rounded; parameres with preapical constriction weakly developed, three thick setae on lateral margin at basal angle of constriction, flattened preapical hyaline setae near mesal margin gradually widening to middle, apex aciculate; internal sac with three large spines, one strongly curved ( Fig. 33 E).

FEMALE: Unknown.

Collecting data. Taken at blacklight. Present from June to August.

Distribution ( Fig. 43 C). Found in coastal areas of Mexico from northern Sonora to Nayarit, and with one specimen taken in Baja California Sur.

Comments. The male abdominal characters serve to place this species near B. mormon . They share the form of tergites 1 and 2, but the impression of tergite 2 is semicircular and a bit smaller, while the impression for B. mormon is wider and more transverse. The dorsal plate of the aedeagus is also different, with the apex broadly rounded in B. mayo , and acutely triangular in B. mormon .

Etymology. The name is derived from the Mayo indigenous group centered in the range of this coastal species that extends from Sonora to Nayarit.

Figures

FIGURE 33. Brachygluta mayo Sabella (Mexico, Sinaloa, paratype). A: Abdomen, dorsal view. B: Abdomen, caudal view. C: Right antenna. D: Left metatibia, anterior view. E: Aedeagus.

FIGURE 43. Distribution map of Brachygluta mormon species-group. A: Brachygluta kiowa Sabella. B: Brachygluta mormon Bowman. C: Brachygluta mayo Sabella. (Red dot: material examined, green dot: only state on label).