Amblypsilopus marskeae sp. nov.

Runyon, Justin B., 2020, The Dolichopodidae (Diptera) of Montserrat, West Indies, ZooKeys 966, pp. 57-151 : 57

Amblypsilopus marskeae sp. nov. Figs 4 , 5

Type material.

Holotype, ♂ labelled: "WEST INDIES: MONTSERRAT/ rental house in Old Town/ 16°44.795'N, 62°13.711'W / 19 JUNE 2017, JB Runyon"; "HOLOTYPE/ ♂ Amblypsilopus / marskeae / Runyon [red label]" (USNM, type number USNMENT01350607). Paratypes: Montserrat: 4 ♂, 5 ♀, same data as holotype; 1 ♂, Woodlands, Riverside House, 5-7 January 2002, Malaise trap, Ivie, Marske & Puliafico; 1 ♂, same as previous, 10-12 January 2002 (MTEC).

Description.

Male (Fig. 4 ). Body length 4.5-5.0 mm, wing length 4.0-4.5 × width 1.1-1.3 mm. Head: Face somewhat narrowed below, three-fifths as wide at frontoclypeal suture as at antenna; face and frons metallic blue-green with violet reflections, with white pruinosity that is coarser and denser on lower face. Palpus yellow, rather narrow and pointed apically, with short yellow setae and two black setae (near 1/2 and at apex). Proboscis yellow, projecting anteriorly, with a few yellow hairs. Antenna with scape and pedicel yellow; first flagellomere brown, ovate-triangular, a little longer than wide, with arista-like stylus inserted near middle of dorsal edge. Lower postocular setae white. Thorax: Scutum and scutellum metallic green with some violet reflections, covered with slight white pruinosity; five pairs of biseriate acrostichal setae, the posterior-most pair much larger (subequal in size to largest dorsocentral setae); five or six pairs of dorsocentral setae, posterior two pairs largest; scutellum with one pair of large marginal setae and one pair of very small lateral setae. Pleuron metallic green with dense white pruinosity. Legs: Coxa I entirely yellow with yellow hairs and three strong yellow distolateral setae; coxa II brown on outer surface with yellow anterior hairs and yellow apical setae, without lateral seta; coxa III entirely yellow with large yellow dorsal seta near 1/2 and a few yellow hairs. Remainder of legs yellow, except distal tarsomeres brownish. Femora unmodified, except femur II has slightly longer rows of black setae pd and posteriorly on apical half; femora lacking anterior preapical setae. Tibia I with small ad seta at 1/5; tibia II (Fig. 4B, C ) slightly sinuous, with row of 4-5 ad setae near apex rapidly increasing in size distally (longest 3 × width of tibia), with row of erect av setae on distal 2/3, longest setae in this row near middle and slightly longer than width of tibia, with pv row of very short erect setae, with 3-4 outstanding ventral setae on basal one-fourth (longest subequal to width of tibia); tibia III with ad seta near 1/5. Tarsus II(1-3) with ad row of erect setae, those at base of tarsus II(1) longest (length ca. 3 × width of tibia) and gradually decreasing in size distally (Fig. 4C ), tarsus II(2-3) with 2-3 slightly longer setae in this row near apex and with rather long black distally directed posterior seta at apex; tarsus II (3-4) very slightly swollen at base bearing small tuft of short black posterior setae; tarsus III(1) with 2-3 black setae ventrally at base. Ratios of tibia:tarsomeres: leg I: 14-18-5-4-2-1; leg II: 20-22-6-5-3-2; leg III: 26-14-6-4-2-1. Wing (Fig. 4D ): Hyaline, narrowly oblong-elliptical; costa without obvious special cilia or setae, but with very short (length subequal to width of costa), erect, fine cilia scattered along costa from just before apex of R1 to near apex of R2+3, the position of these minute cilia seems to correspond to the longer, curved costal cilia found in other Amblypsilopus species (e.g., A. bredini Robinson); vein M branched, M1 strongly arched anteriorly just beyond branch and ending in wing apex; M2 fading and not reaching wing margin; crossvein dm-cu nearly 3 × as long as last part of CuA1. Calypter yellow with edge narrowly black, with fan of long yellow setae. Halter yellow. Abdomen: Narrow, cylindrical. Tergite I yellow with posterolateral edge narrowly brown, with yellow hairs and longer black setae on posterior margin; remainder of tergites with black hairs and setae, those near posterior margins larger; tergite II entirely yellow on basal one-fourth and on most of lateral surface, brown with metallic green reflections dorsally and along posterior margin; tergites III and IV mostly yellow laterally and brown with metallic green reflections dorsally and along posterior margins; tergites V-VII entirely metallic green; tergite VII mostly bare except four large setae along posterior margin. Sternites I-IV yellow with sparse yellow hairs; sternites V and VI brown with mostly dark hairs and setae; sternite VII reduced to a sclerotized band attached to ovate setose sternite VIII which covers the hypopygial foramen. Hypopygium (Fig. 5 ) rather small, on a short, broad peduncle formed by tergite VII. Hypopygial foramen at base on left side. Epandrium brown, a little longer than wide, rather square apically, covered with white microtrichia that is densest at ventroapical corner. Surstylus shining dark brown, bilobed, with large oval ventral lobe bearing four large setae and small digitiform medial lobe with three small setae near apex; dorsal lobe of surstylus slender, finger-like with three ventral setae near apex. Cercus yellow, elongate cylindrical but broader basally, covered with abundant setae (color of setae varies from yellow to dark brown) especially along ventral surface, and with four long black wavy setae at apex. Phallus broad, slightly flared at apex with large opening, with sclerotized articulation near 2/3, near where phallus emerges from hypandrium. Hypandrium sclerotized dark brown, asymmetrical, with broad ventral hood bearing hairs at pointed apex and left lateral lobe arising near base that crosses dorsally to right side of phallus, this lobe has minute scale-like setae on apical half. Subepandrial sclerite with sharply pointed, slightly hooked process emerging just ventral to base of cercus.

Female. Body length 4.5-5.0 mm, wing length 4.0-4.5 × width 1.3-1.5 mm. Similar to male, but clypeus more distinct and bulging; three yellow distolateral setae on coxa I stronger than in male; leg II unmodified, tibia II with small ad and pv seta near 1/5 and smaller pv seta near 1/2; wing noticeably broader.

Etymology.

This species is named to honor Dr. Katharine A. Marske (University of Oklahoma). Many specimens used in this study were collected as part of Katie’s Master’s thesis at Montana State University examining the effects of volcanic ash on Montserrat forest insects ( Marske 2004), a component of the Centre Hills Biodiversity Assessment.

Distribution.

Montserrat.

Remarks.

Amblypsilopus marskeae belongs to the New World group of Amblypsilopus species that possess costal cilia (which are poorly developed in A. marskeae ) and three strong distolateral setae on coxa I that are more strongly developed in females. Amblypsilopus marskeae is closely related to A. bredini (Robinson) from Dominica which has a similarly sinuous tibia II but differs most notably in color of the thorax and males lacking long, hooked cilia on the costa. Specimens were collected at the type locality from a shaded, vertical surface of a roadside concrete wall and on low vegetation in an adjacent small ghaut.

Figures

Figure 4. Amblypsilopus marskeae sp. nov. males A habitus of holotype, left lateral B tibia II and base of tarsus II (1), anterodorsal view C tip of tibia II and tarsus II (1), dorsal D wing, dorsal. Scale bars: 1 mm.

Figure 5. Amblypsilopus marskeae sp. nov. male terminalia, left lateral. Abbreviations: epand-epandrium; hypand-hypandrium; TVII-tergite 7; SVIII-sternite 8. Scale bar: 0.5 mm.