Boreantrops albipes, Kits, Joel H. & Marshall, Stephen A., 2015

Kits, Joel H. & Marshall, Stephen A., 2015, A revision of Boreantrops Kits & Marshall (Diptera: Sphaeroceridae: Archiborborinae), Zootaxa 3915 (3), pp. 301-355 : 311-312

Boreantrops albipes sp. nov.

( Figs. 2 , 9 , 31, 32 , 103)

Diagnosis. Separable from other members of the avignis subgroup by the following combination of characters: Occiput brown with a yellowish orange semicircle behind gena. Mesoscutum mostly shiny, scutellum shiny laterally with a medial stripe of microtomentum. Katepisternum mostly shiny. Fore tarsus with all tarsomeres white.

Description. Head yellow to orange, occiput mostly brown with yellowish orange semicircle behind gena ( Fig. 2 ). Microtomentum on frons at anterior corners and around base of postvertical bristles, along ventral margin of gena, thin band on face below lunule and antenna, on prementum, and on occiput. Ocellar bristles just anterior to median ocellus. Subvibrissal bristle and anterior genal bristle about 0.5X length of vibrissa.

Thorax black, mostly shiny with scattered microtomentum on mesoscutum in acrostichal area, on scutellum in a medial stripe and along lateral margins, on anepisternum along posterior third except ventral corner, on katepisternum outlining a shiny patch behind fore coxa and ventrally, on anepimeron and laterotergite, and metapleuron. Mesoscutum sculptured. Scutellum subtriangular, dorsal surface concave medially ( Fig. 9 ). Halter whitish.

Legs black, trochanters yellow, joints paler. Fore tarsus with all tarsomeres ivory white, mid and hind tarsi with 4 basal tarsomeres ivory white, distal tarsomere brown. Mid tibia with one preapical anterodorsal, 4 subapical bristles. Hind tibia with one ventroapical bristle.

Wing clear, veins yellow to light brown.

Abdomen with tergites and sternites weakly sclerotized. Syntergite 1+2 with posterolateral corners and a thin band between them strongly sclerotized, tergites 3–4 with a thin posterior band moderately sclerotized. Pleural setae on small discs, about the diameter of spiracles.

Male postabdomen: Sternite 5 narrow, posterior corners slightly flared, posterior margin entire with a complete row of setae, anterior apodeme about one-third as long as external portion ( Fig. 32 ). Surstylus long, paddle-shaped. Hypandrial arms with ventral tab-like structures. Pregonite fused with postgonite. Postgonite with lobes not separated, anterior lobe truncate, posterior lobe pointed. Basiphallus with long epiphallus, long, thin, transparent preepiphallus. Distiphallus with curved dorsal tube with raised sculpturing but not distinct spines, distal tip very thin ( Fig. 31 ).

Female postabdomen: Tergites 6–7 and sternites 6–7 moderately sclerotized. Tergites with 3 posterior strips, sternites with 2 posterior strips. Tergite 8 trapezoidal, shallowly emarginated anteriorly, covered with microtomentum except anterior margin. Epiproct without anterior arms, with microtomentum medially, with 1 pair of setae. Cerci broad. Sclerites of sternite 8 broad posteriorly, pointed anteriorly, posterior two-thirds covered with microtomentum. Hypoproct broad, shallowly emarginated anteriorly. Spermathecae barrel-shaped, about 1.5X longer than wide, invaginated apically, sclerotized duct short.

Type material. Holotype ♂: COSTA RICA: Alajuela: San Gerardo Biol. Stn., 10°52'51"N 85°23'20"W, 590 m, on monkey dung, 15 Aug 2010, J.H. Kits, debu00338382 ( INBC). Paratypes: same data as holotype (3 ♂, 3 ♀, DEBU, INBC); Volcán Tenorio, N slope nr. Bijagua Biol. Stn., 700 m, rain forest, RET over Atta mound, 16–20 Jun 2000, S.A. Marshall (1 ♀, DEBU); Guanacaste: Guanacaste Cons. Area, Maritza Field Stn., 875 m, Malaise, 3–9 Feb 1994, J. Noyes (1 ♀, DEBU); Limón: Cuatro Esuinas, P.N. Tortuguero, 1 Oct 1989, J. Solano (1 ♀, INBC).

Distribution. Northern Costa Rica (Fig. 103). Most specimens are from montane rainforest from 590–875 m elevation.

Etymology. The species name refers to the entirely white fore tarsi.

Comments. This species occurs syntopically with the very similar B. avignis at the type locality; both species were collected in the same series from splatters of monkey dung along a trail. Some individuals were observed perched on the dung slowly waving their forelegs; the difference in fore tarsus colouration between these species may play some role in species recognition. No associated behaviours or interactions were observed and the sex of the waving flies could not be determined in the field.

Figures

FIGURES 1 – 4. Boreantrops, images of living flies. 1) B. inbio, San Gerardo de Dota, San José, Costa Rica; 2) B. albipes, San Gerardo Biological Station, Alajuela, Costa Rica; 3) B. wayqecha, Wayqecha Biological Station, Cusco, Peru; 4) B. auranticeps, Bellavista Cloud Forest Reserve, Pichincha, Ecuador. 1, 3, and 4 by SAM, 2 by Morgan Jackson, used with permission.

FIGURES 9 – 14. Boreantrops specimens, head and thorax, dorsal. 9) B. albipes; 10) B. avignis; 11) B. hispidus; 12) B. inbio; 13) B. subemarginatus; 14) B. zacapa. ads: additional setulae.

FIGURES 31 – 36. Boreantrops male terminalia. B. albipes: 31) phallus, postgonite, and phallapodeme, lateral view, 32) sternite 5; B. alytothrix: 33) phallus, postgonite, and phallapodeme, lateral view, 34) sternite 5; B. apterus: 35) phallus, postgonite, and phallapodeme, lateral view, 36) sternite 5. bp: basiphallus, dp: distiphallus, dt: dorsal tube; ep: epiphallus, keel: transparent keel on dorsal tube; pa: phallapodeme, pep: preepiphallus, prg: pregonite, ptg: postgonite.