Wilcoxia forbesi Pollock & Reichert, 2019

Pollock, Darren A. & Reichert, Lisa A., 2019, Review of the Nearctic genus Wilcoxia James (Diptera: Asilidae: Stenopogoninae) with descriptions of three new species, Zootaxa 4695 (5), pp. 401-437 : 419-420

7. Wilcoxia forbesi Pollock & Reichert , n. sp.

( Figs 13–14 , 23–24 , 34–35 , 38, 40 , 56 , 65 , 78–80 )

Holotype (here designated), male, labeled: “N. MEX. Dona Ana Co. 1miNW Tortugas Mt. 4100’ (E of Jct. , Univ. and Telshore) G. Forbes 20 NOV 1983 // NMSU // [red label] HOLOTYPE ♂ Wilcoxia forbesi Pollock & Reichert ”, in CAS . Allotype, female, labeled: “N. MEX. Dona Ana Co. 1miNW Tortugas Mt. 4100’ (E of Jct. , Univ. and Telshore) G. Forbes 20 NOV 1983 // 21119 // [green label] NMSU // [red label] ALLOTYPE ♀ Wilcoxia forbesi Pollock & Reichert ”, in CAS .

Paratypes, from the following localities (all with light blue “ PARATYPE Wilcoxia forbesi , n. sp. Pollock & Reichert ” labels): UNITED STATES OF AMERICA. New Mexico. Doña Ana Co. Dunes 4400’ 1.3 mi NW jct C7/C8, NW of Corralitos [32.295362, -107.038391], 4.xi.1984, G. Forbes, gravel, ( NMSU, 4♂, 6♀), ( CASC, 1♀) ; 1 mi NW Tortugas Mt., 4100’ (E. of Jct., Univ. and Telshore ) [32.302989, -106.708571], 11.xi.1984, G. Forbes, ( NMSU, 2♂, 3♀) ; same locality, 20.xi.1983, G.S. Forbes, ( CASC, 1 ♂, 4♀; BYUC, 1♀) ; same locality, 15.xi.1983, G. Forbes, ( NMSU, 1♀, EMFC, 1♂) ; 3.2 mi E Tortugas Mt. [32.292071, -106.640091], 4300’, 11.xi.1984, G.S. Forbes, ( NMSU, 1♂) ; N. Base, Tortugas Mt. [32.297363, -106.697996], 4200’, 1.xi.1984, G.S. Forbes, ( NMSU, 7♂, 2 ♀; BYUC, 1♂) ; 5.1 mi. E. Tortugas Mt. [est. at 32.291374, -106.594039], 5000’, 13.xi.1982, G.S. Forbes, ( EMEC, 2♀ [ EMEC 1135 625, 1135628]; NMSU, 1♂) ; same locality, 3.xi.1985, G.S. Forbes, ( NMSU, 2♂, 3♀) ; 4 mi E. Tortugas Mtn. [32.290898, -106.627066], 4.i.1985, D. Lightfoot & G.S. Forbes, ( NMSU, 1♂, 1♀) ; 4 mi NE of Tortugas Mt. [32.332278, -106.647555], 4800 ft., 20.i.1985, D. Lightfoot, ( NSMU, 1♀) ; Tortugas Mtn., nr. Las Cruces , 32.296075, -106.706497 [32.296075, -106.706497], 4245 ft., 3.i.2017, D. & G. Pollock, L. Reichert, collected on small to medium rocks on rocky/stony terrain, ( ENMU, 15♂, 13♀) ; same locality and data, 4.i.2017, ( ENMU, 5♂, 10♀) ; Jornada LTER site, 1.0 mi SE College Rch [32.519662, -106.791872], 4400’, 28.x.1984, G.S. Forbes, ( NMSU, 2♂) ; Jornada LTER site, 1 mi SW College Rch [32.520249, -106.816191], 4300’, 1.xii.1984, G.S. Forbes, ( NMSU, 2♂) ; Jornada Range, 2 mi SW Coll Rch HQ [32.510074, -106.828202], 4500’, 7.xi.1983, D. Lightfoot, ( NSMU, 1♂) ; Doña Ana Mts. , 4700’, 6.6 mi N rt. 70/82, 2.4 mi W Jornada rd [32.475142, -106.777375], 28.xi.1981, G. Forbes, ( NMSU, 1♂, 1♀) . Otero Co. 32°75260N, 105°92825W [32.75260, -105.92825], 4187 ft., xi.2010, B. Barker, ( EMFC, 3♂, 3♀) . Texas. Reeves Co. Rt. 290, 3.6 mi W. jct at Toyahvale [30.941876, - 103.847704], 8.xii.1985, G. Forbes, ( NMSU, 1♀) .

Derivation of specific epithet: named in honor of Gregory S. Forbes, assiduous collector of robber flies in New Mexico, including most specimens of this new species.

Diagnosis. This species may be separated from the other three members of the martinorum group (of which it is the most distinct) by the following characters: sexes dimorphic: abdomen of females with pattern of pollinose and non-pollinose areas, males with abdomen uniformly pollinose; costa incomplete, only traceable to near junction of CuA 2 and wing margin; halter knob pink, distinctly contrasting yellow stem; mystax of male very dense ( Figs 13 , 23 ); femora entirely bare, without pollinose patch(es).

Description. Male ( Fig. 13 ). TL 4.4–7.1 mm; wing 4.4–5.6 mm.

Head ( Fig. 23 ) black, covered in pale grey tomentum; face (in profile) projecting slightly beyond eye; hairs and setae of head white; lower occipital hairs long, very dense, “wispy”; ocellar tubercle with many long, fine setae and some hairs (ca. length of postpedicel + style); mystax ( Fig. 23 ) very dense, consisting of very long hairs (> length of antenna), occupying almost entire face; hairs white, bases perpendicular to slightly less than 90° from plane of face; no distinct hairs on face separate from mystax; palpi and proboscis black with white hairs; antennomeres brown to black, pollinose, scape thinly pollinose; scape and pedicel with long ventral setae (pedicel with one longer hair/seta) and hairs, and several relatively short hairs dorsally; ratio of antennomere lengths (scape: pedicel: postpedicel: style + spine) = 6: 6: 14: 9.

Thorax black, covered in pale grey tomentum; scutum with median stripe absent, marked in some individuals by linear areas of sparser tomentum; acrostichal setae present, though difficult to discern from long hairs, 5–6 per row; scutum surface uniform, without distinct non-pollinose or differently colored spots; scutum with moderately dense pile of long white hairs (> length of postpedicel), length and density subequal pre- and postsuturally; most specimens with 3 notopleural setae, 2 supraalar setae, and 1 postalar seta; stoutest thoracic setae with amber cast; scutellum uniformly pale grey pollinose; 6–8 white marginal setae, longest setae greater in length than scutellum, perpendicular to plane of scutellum; very few short marginal hairs present; disc of scutellum with few shorter, partially appressed hairs; pleura pale grey pollinose; katatergite with about 20 long fine white setae, tips “crinkly”; wings hyaline; costa incomplete, present to near apex of anal lobe only ( Fig. 38 ); microtrichiae sparse and incon- spicuous on entire wing ( Fig. 40 ); halter with base brown and yellow, stem yellow, knob pink to light purple; legs ( Figs 13–14 ) uniformly black, entirely bare, without pollinosity on femora; hairs and setae white; femora dorsally with moderately dense, white appressed hairs (<femur width) and a few longer, suberect setae (> femur width); ven- trally with longer, suberect white hairs (longest ca. femur width); tibiae with relatively dense, short (<tibia width) appressed white hairs, ventrally with a few longer (longest> tibia width), suberect hairs, slightly more abundant on front tibiae; mesotibial spine very light yellow; protibiae without sigmoidal spine.

Abdomen ( Figs 13 , 34 ) black, tergites 2–7 densely pale grey pollinose, pollinosity slightly less dense anteriorly on tergites; hairs white; tergite 1 bare dorsocentrally, bare patch widened anteriorly; tergite 2 bare anterior of punctillae and with bare narrow posterior margin; tergite 3 with bare narrow posterior margin; sternites pale grey pollinose, with moderately long, fine white hairs, slightly longer on anterior sternites.

Male genitalia ( Fig. 56 ). Apex of dorsal gonocoxite process relatively shallowly bifid, inner lobe distinctly longer than outer, carina on outer lobe absent; dorsal process extending past apex of ventral gonocoxite process; medial gonocoxite processes moderately thin, moderately curved towards phallus; gonostylus relatively thin, arcuate, apex not truncate; phallus without distinct, subapical denticle on lateral margins; lateral margins evenly narrowed to apex.

Female ( Fig. 14 ). TL 5.0– 7.2 mm; wing 4.2–6.3 mm. Features similar to male, except for the following: pale grey pollinosity of head and thorax with very light to medium brown tint; mystax ( Fig. 24 ) much sparser than male, but most hairs still ca. length of antennae; abdomen ( Figs 14 , 35 ) dorsally largely bare, shiny black, pale grey pollinosity confined to lateral areas of tergite 1; tergite 2 with narrow band of pollinosity anterior of punctillae, lateral margins and posterolateral margins extending medially on posterior margin but not connecting, leaving center of posterior margin non-pollinose; tergites 2–5 with pollinosity in anterior band, and on lateral margins, expanded dorsomedially, leaving center of posterior margin non- or thinly pollinose; tergite 6 bare, in some specimens with some pollinosity, confined to extreme lateral margins; tergite 7 bare; sternites 2–5 pollinose, 6 lightly pollinose, confined to anterolateral margins; sternite 7 bare.

Notes. Couplet 28 in Wood’s (1981) key that leads eventually to Wilcoxia mentions “C [costa] continuing around posterior wing margin to wing base”. Because the costa is abbreviated in individuals of W. forbesi , the second part of the above couplet is not completely accurate. The first part of the couplet leads to genus Itolia Wilcox , based on peculiarities of the wing venation and shiny areas on the scutum.

Natural history. On 3–4 January 2017, specimens of W. forbesi were collected on the rocky terrain at the base of Tortugas Mtn., near Las Cruces, Doña Ana Co., NM ( Figs 78–80 ). Flies were observed on small (6 inch maximum dimension) to medium-large rocks (1–2 foot maximum dimension, e.g. Fig. 80 ). Sweeping was done in this area also, but no flies were collected on vegetation. Among the 43 specimens (20 males, 23 females) collected on these two days, 11 (3 males, 8 females) were taken with associated prey. Ten of these were winged males of a species of scale insect [ HEMIPTERA (Sternorrhyncha) : Margarodidae : Margarodes sp.] and one was a small fly ( DIPTERA : Drosophilidae ). Bulk index of the prey items ranged from 0.4–1.4; ratio of bulk index of predator:prey ranged from 8.3–27.4 (average = 16.2). Specimens were collected from 28.x–20.i.

Distribution ( Fig. 65 ). As mentioned above for W. apache , the distribution of W. forbesi is sympatric with the western “cluster” of W. apache . Almost all specimens of W. forbesi were collected in Doña Ana County, near Las Cruces. Elevations range from 3,490 to 5,382 feet.

Figures

FIGURES 13–16. Figs 13–14. Male (13) and female (14) paratypes of W. forbesi, n. sp. Both specimens from Doña Ana Co., NM. Figs 15–16. Male (15) and female (16) paratype of W. martinorum Wilcox. Both specimens from Riverside Co., CA.

FIGURES 17–25. Laterofrontal view of head of Wilcoxia spp. 17. W. cinerea, male. 18. W. monae, male. 19. W. painteri, male. 20. W. pollinosa, male. 21. W. apache, n. sp., male. 22. W. flavipennis, n. sp., male. 23. W. forbesi, n. sp., male. 24. W. forbesi, n. sp., female. 25. W. martinorum, male.

FIGURES 30–37. Abdomens of Wilcoxia spp. (martinorum group), dorsal. 30. W. apache, n. sp., male; 31. W. apache, n. sp., female; 32. W. flavipennis n. sp., male; 33. W. flavipennis, n. sp., female. 34. W. forbesi, n. sp., male. 35. W. forbesi, n. sp., female. 36. W. martinorum, male. 37. W. martinorum, female.

FIGURES 38–40. Fig. 38. Wing of male W. forbesi, n. sp. showing abbreviated costa (not present to wing base). Fig. 39. Apex of wing of male W. pollinosa, showing dense microtrichial field on wing membrane. Fig. 40. Detail of wing of male W. forbesi n. sp. showing lack of conspicuous microtrichiae on wing membrane.

FIGURES 47–58. Male genitalia (47–57) and ovipositor (58) of Wilcoxia spp. 47. W. cinerea, ventral view (epandrium removed). 48. W. monae, ventral view (epandrium removed). 49–50. W. painteri, ventral and right lateral view. 51–52. W. pollinosa, ventral (epandrium removed) and slightly oblique view. 53–54. W. apache, n. sp., ventral and dorsal oblique view. 55. W. flavipennis, n. sp., ventral view. 56. W. forbesi, n. sp., dorsal view (epandrium removed). 57. W. martinorum, ventral view (epandrium removed). 58. W. apache, n. sp., terminal abdominal segments and ovipositor. dp = dorsal gonocoxite process; dpc = dorsal gonocoxite process carina; gc = gonocoxite; gs = gonostylus; lep = lateral ejaculatory process; mp = medial gonocoxite process; pd = phallus denticle; ph = phallus; vp = ventral gonocoxite process.

FIGURES 65–66. Known distributions of W. forbesi, n. sp. (65) and W. martinorum Wilcox (66) (maps created at www.gpsvisualizer.com).

FIGURES 77–80. Habitats of Wilcoxia spp. 77. W. apache, n. sp., “atypical” habitat/substrate, field east of Railroad Mtn. Rd., Roosevelt Co., NM. Specimens were seen/collected along this sandy track through prairie. 78–79. W. forbesi, n. sp., habitat, base of Tortugas Mtn., Doña Ana Co., NM. 80. Female W. forbesi, n. sp., on typical substrate, Tortugas Mtn., Doña Ana Co., NM (photo credit: George W. Pollock).