Brachygluta (Brachygluta) elegans (Brendel, 1890)

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 : 57-59

19. Brachygluta (Brachygluta) elegans (Brendel, 1890)

( Figs 24 , 41 D)

Bryaxis (Nisa) elegans Brendel, 1890: 276 , pl. VIII, fig. 48. Type locality: Williams, Arizona. AZ. Type depository ANSP, Holotype female: // Ariz./ Williams/ type / Bryaxis elegans Br. / [red label] HOLOTYPE Bryaxis elegans Brendel //. This type specimen originally lacked an ANSP number; Type number assigned on May 2013 is ANSP 8396. Moxey 1962: 97.

Brachygluta elegans: Raffray 1904: 226 ; 1908: 231; 1911: 95. Leng 1920: 130. Bowman 1934: 88 (Group III, key). Chandler 1994: 50; 1997: 55. Poole & Gentili 1996: 380.

Material examined, 5 specimens. USA: Arizona: Cochise Co. : Chiricahua Nat. Mon., VIII-8-58, R.O. Schuster, L.M. Smith Colrs. ( UCDC, 1). Coronado N(ational) F(orest), Chiricahua Mts., VIII-5-2013, C. Carlton & B. Owens, sifted litter-Berlese ( LSAM, 2). Coconino Co.: Williams (holotype, ANSP, 1). Only state on label: “Ariz.” ( CMNH, 1).

Description. BODY: Length 1.76–1.84 mm; orange-brown to red-brown; head and pronotum with setae short, curved and suberect, over rest of body decumbent to appressed. Head: surface smooth, shining, punctures indistinct. Antennomeres III–VI longer than wide, VII as long as wide, VIII–X strongly transverse, VIII about twothirds width of IX ( Fig. 24 C). Setose area of median vertexal fovea as large as those of lateral foveae, setose areas smaller than in other species. Pronotum: surface smooth, shining, punctures indistinct. Setose area of median antebasal fovea about two-thirds width of lateral antebasal foveae, setose areas relatively small when compared to other species. Elytra: with microreticulation faint to distinct, punctures indistinct, discal stria extending to about four-fifths of elytral length. Abdomen: disc smooth, shining, punctures minute; basal striae of tergite 1 elongate, one-half paratergite length, slightly divergent, separated at base by about one-half tergite width, setose brush distinct between bases of striae.

MALE: Antennae and trochanters unmodified, simple. Metaventrite with area of longer setae only between metacoxae. Tergite 1 with shallow small emargination at apex; tergite 2 with short, shallow arcuate impression at base, at base small median triangular acutely pointed tubercle arises from short transverse carina ventral to apex of tergite 1; disc of 2 and following tergites smooth, shining, impunctate ( Figs 24 A–B). In lateral view 1 nearly level, projecting posteriorly and above base of 2, 2–4 confluently curved. Metatibiae thin, narrow at base, gradually widened to near apex, mesal margin of apical third with brush present ( Fig. 24 D). Ventrites broadly convex. Aedeagus 0.33 long mm; with dorsal plate broadly triangular, apex bluntly rounded; parameres with three thin setae at posterior margin of preapical constriction, hyaline setae flattened, elongate, tapering from near base to acute point; internal sac with three thick spines, two strongly curved ( Fig. 24 E).

FEMALE: Microreticulation on elytra distinct. Metaventrite with setae sparse. Abdomen lacking modifications; ventrites broadly convex. Metatibiae similar to that of male.

Collecting data. Three specimens were taken in August, with two of these being sifted from litter.

Distribution ( Fig. 41 D). Only known from higher forested elevations in two distant areas of Arizona.

Comments. Brendel originally placed this species in the cavicornis species-group ( Nisa ) due to its relatively small median prothoracic fovea. However, this species lacks the punctate dorsum typical of the cavicornis speciesgroup, and resembles more closely B. arguta and others of this species group in the shining cuticle, long basal discal striae of tergite 1, the simple apex of tergite 1, and its small size. It is separated from the other species in this group by the comparatively simple tergite 2, where the median basal impression is faint and the median triangular spine at the base is clearly visible in posterior view.

Figures

FIGURE 24. Brachygluta elegans (Brendel). A: Abdomen, dorsal view (Arizona, Cochise Co.). B: Abdomen, caudal view (Arizona, Cochise Co.). C: Right antenna (Arizona, Cochise Co.). D: Left metatibia, anterior view (Arizona, Cochise Co.). E: Aedeagus (Arizona).

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).