Conchopus minutus, Masunaga, Kazuhiro & Saigusa, Toyohei, 2010

Masunaga, Kazuhiro & Saigusa, Toyohei, 2010, A revision of the Hawaiian and Wake Island species of the genus Conchopus Takagi (Diptera, Dolichopodidae), Zootaxa 2729, pp. 1-35 : 19-24

Conchopus minutus sp. nov.

( Figs. 10 , 11 , 12 , 18 d)

Diagnosis. Small-sized species (2.5–2.9 mm in body length) characterized by 1st flagellomere being twice as long as its basal thickness; halter yellow. In male M1+2 thickened, apical section of M3+4 2.6 times as long as discal crossvein; discal crossvein very oblique; fore tarsomere 1 with large basal lobe 2/5 as long as tarsomere 1, strong ventral bristle beyond midlength, and moderately large apical swelling; longer dorsal bristle of fore tarsomere 2 slightly before middle; mid tibia cylindrical, without long erect bristles and setae on anterior and posterior surfaces; mid tarsomere 1 short setose; ventral lobe of hypopygium simple, slightly produced distally.

Description. Male: Body length 2.5–2.9 mm; wing length 2.7–2.9 mm. Head: l.7–1.8 times as deep as long; frons, vertex, and upper half of occiput blackish-brown pollinose, with slight brownish tinge on frons just above antennal base. Dark green coloration of occipital integument faintly apparent through its pollinosity. Face, palpus, proboscis, and lower half of occiput ash-gray pollinose, darker on latter two areas; face at narrowest point 0.2 times as wide as head, gradually widening dorsally and ventrally, widest ventral part l.5 times as wide as narrowest point. Proboscis 0.4 times as long as eye height. Antenna 0.5–0.6 times as long as head; 1st flagellomere as long as two basal segments together, or 1.9 times as long as thick, gently and gradually constricted on dorsal margin, almost straight for basal 2/3, then curving dorsally towards tip on ventral margin, inner surface bearing 3–4 setulae near base towards dorsal margin, 2–3 setulae at midlength towards ventral margin; arista l.3–1.5 times as long as 3 antennal segments together. Thorax: Mesonotum viewed from above, humerus brownish gray, inverted Y-shaped mark blackish brown, with borders not sharply defined, 1st dc on obscure border, 2nd dc on blackish area, presutural dark prolongation narrow but distinct; prescutellar white marking rectangular, anterior margin usually weakly prolonged into short, narrow acrostichal streak, lateral margins slightly emarginated at 5th and 6th dc, these being situated on blackish area; cuneiform dark incision in prescutellar white marking usually broad basally, then tapered into parallel-sided band extending anteriorly slightly beyond level of 5th dc. Supra-alar area (surrounded by sutural and 2 supra-alar bristles), postalar callus, and scutellum dark grayish-brown pollinose. Pleura gray pollinose white slight bluish or greenish tinge. Acrostichals 7–12 in number; irregularly biserial in front, uniserial behind, ending between levels of 1st and 2nd dc, or reaching to level of latter, but only very rarely extending more posteriorly, acrostichals all reclinate. Propleurals 3–5 (usually 4), mesopleurals 3–6 (usually 3 or 4), latter arranged in vertical row along upper portion of hind margin of anepisternum near basalare but lowermost setulae not reaching level of ventral extension of basalare. Scutellum almost always with 2 weak outer bristles besides inner pair of strong bristles, but 1 or both outer bristles rarely absent. Legs: Coxae and femora gray pollinose with slight bluish or greenish tinge, femora darker and subshining with greenish integument apparent. Tibiae and tarsi blackish brown with thin coating of grayish pollen. Foreleg ( Figs. 10 a-b): Coxa clothed with 2 rows of bristles on anterior surface, of which outer row of 4–6 quite strong, coxa also with long bristles on anterior distal margins. Femur 5.5 times as long as thick, gradually tapered apically; preapical tubercle situated 0.2–0.3 from tip. Tibia slightly curved dorsally towards tip, preapical portion weakly swollen, l.6–1.7 times as thick as narrowest part of tibia; anterodorsal and anteroventral setae lengthened apically, bristles of former row inclined, those of latter row more or less erect and prominent; preapical posteroventral bristle very strong (as long as thickness of tibia at midlength), anterior preapical mass of setae well developed. Tarsomere 1 short, well arched dorsally; basal lobe well developed, evenly rounded ventrally, 0.6–0.7 times as thick as long, 0.4 times as long as tarsomere 1, with 8–11 submarginal setulae (these forming row from ventral submargin of posterior surface to distal margin) and 3–4 (usually 4) marginal setulae (setulae in short row on ventral margin), all these setulae rather long; ventral bristle strong, nearly l.5 times as long as thickness of tarsomere 1, situated slightly beyond midlength of latter; a few weak setulae before ventral bristle, these much weaker than marginal setulae of ventral lobe; apical swelling of tarsomere 1 prominent (thickness of tarsomere at apical swelling 0.8 times that at basal lobe), produced ventrodistally; anterior preapical cluster of setulae close to tip of tarsomere 1, almost at level of posterior preapical bristle. Tarsomere 2 with strong anterodorsal bristle of l/4 its length, situated 0.4–0.5 from base of tarsomere, 1 additional short bristle often appearing at midlength of tarsomere. Tarsomeres 3–5 simple. Midleg ( Fig. 10 c): Coxa with row of many bristles extending from middle of outer surface to anterodistal corner, uppermost bristle very strong, bristles on anterodistal corner dense. Femur weakly depressed dorsoventrally, thickest and widest at proximal l/4, gently tapered apically, with anterior and dorsal margins weakly arched, posterior one very slightly incurved, and ventral one almost straight; anteroventral bristles lengthened in basal half, posteroventral bristles inclined, both 0.5 times as long as thickness of femur and becoming shorter apically; 4–5 anterior bristles on apical half of femur and posterior preapical bristle strong. Tibia slender, cylindrical, straight and simple, clothed with 8 rows of short setae and bearing 2 pairs of posterodorsal bristles, these as long as width of tibia, one pair situated l/4 from base, another beyond midlength (variable, from just before midlength to point 2/5 from tip), posterodorsal bristles located beyond midlength and almost always situated more basally than anterodorsal ones. Tarsus slender, simple, with short setae; anterior bristles of tarsomere 1 not or very slightly differentiated from other setulae. Hindleg: Coxa with 3 outer bristles (uppermost one as strong as that of middle coxa) and long fine bristle at anterodistal angle. Trochanter with several short normal setae. Femur weakly curved posteriorly and ventrally, with short setulae and numerous antero- and posteroventral setae, shorter than half thickness of femur, including 4–5 strong anterodorsal bristles on apical half. Tibia slender and straight, with very weak apical process posteroventrally, this only as long as thickness of tibia and only slightly exceeding tip of tibia; chaetotaxy resembling that of mid tibia, but usually dorsal bristles beyond middle posteroventral bristle absent and anteroventral preapical bristle somewhat stronger. Tarsus simple, slender, with short setulae. Wing ( Fig. 18 d): Evenly pale gray but slightly infuscated brownish in basal half of space C and basal cell 1, fold along M1+2 black. Wing somewhat broad, usually shorter than 3 times width. Basal l/3 of veins R2+3 and R4+5 not incrassate, as thick as or more slender than middle of vein Sc; apical section of M1+2 gently divergent from R4+5 towards tip in basal half, then weakly bent anteriorly, finally parallel with R4+5 towards tip, also thickened from middle of discal cell to basal 1/4 of M1, with upper side of thickened portion overlapped by wing membrane from posterior side; discal crossvein oblique, so discal cell pointed at posterodistal corner. Ratio of M1 to apical section of M1+2 2.0–2.4; ratio of middle section of M3+4 to apical section of M3+ 4 l. 5–1.9. Halter yellow; bristles and setae black. Abdomen ( Figs. 11 a-c): Gray pollinose with slight bluish or greenish tinge, but abdominal terga darker and subshining, with greenish integument apparent, and tergum 8 almost ash-gray like epandrium. Terga evenly clothed with short setulae. Sternum 1 strongly emarginate anteriorly, fused with sternum 2 posteriorly; sterna 2–4 normal, discal bristles of sternum 4 weak, not spine-like. Sternum 5 with pair of subventral clusters of 3–5 strong, spinelike bristles; from each cluster row of a few subventral setae extending posteriorly, this row fairly well distinguished from group of bristles broadly covering posterolateral portions of sternum, but connected to this group of bristles by marginal row of bristles, of which 2–3 subventral ones somewhat stronger than others; sternum 5 also with strong, blunt-ended spine at each posterolateral corner. Sternum 6 nearly as long as wide, deeply concave ventromedially, weakly and bluntly expanded laterally, broadly desclerotized on disc. Lamellate apodemal processes large, broad, triangular, and widely divergent from each other. Pedunculate process of sternum 6 long; its membranous club 0.5–0.6 times as long as process itself, and in profile almost of same width, with anterior margin weakly concave beyond midlength, posterior margin almost straight, and apex large and truncate; spinules of lateral surface moderately large, those on anterior surface compact and depressed, each shagreened unit of posterior surface. Hypopygium ( Figs. 12 a–e): Cercus 1.1 times as long as height of epandrial capsule, not very elongate, broadest at about apical 0.3, broadly emarginate on inner margin, with apex broadly rounded and weakly produced distally. Ventral lobe 0.5 times as long as cercus, flattened longitudinally, 3.5 times as long as wide, very weakly dilated towards apical margin, latter fringed with 6 bristles and protruded into short process at each apical corner; a few setulae scattered on posterior surface of ventral lobe. Hypandrium about as long as ventral lobe. Female: Similar to male, but face at narrowest point 0.25 times as wide as head. Proboscis 0.63 times as long as eye height: Relative lengths of tarsomeres 1–5 30:23:14:9: 16 in foreleg; 52:28:16:10: 15 in midleg; 45:43:24:11: 15 in hindleg. Wing: Apical section of M3+4 2.3–2.6 times as long as discal crossvein. Body length 2.5–2.7 mm; wing length 2.9–3.2 mm.

Material examined. HOLOTYPE ɗ, Hulopoe Beach, Läna‘i, 16.xii.2002, K. Masunaga leg. ( BPBM). PARATYPES ( BPBM, LBM, BLKU): Hawai‘i: 1Ψ, Kailua-Kona, 29.ix.1966, W.J. Voss leg.; 5ɗ1Ψ, Hilo, 23.iii.1967, J.R. Vockeroth leg.; 3ɗ11Ψ, Kalapana Pk., 24.iii.1967, J.R. Vockeroth leg.; 23ɗ10Ψ, Leleiwi, 13.xii.2002, K. Masunaga leg.; 11 ɗ, Honaunau, 14.xii.2002, K. Masunaga leg.; 5ɗ, Kapaa Beach, 14.xii.2002, K. Masunaga leg.; 8ɗ, Black Sands Beach, 15.xii.2002, K. Masunaga leg. L ā na‘i: 138ɗ135Ψ, Hulopoe Beach, 16.xii.2002, K. Masunaga leg.; 62ɗ45Ψ, Hulopoe Beach, 17.xii.2002, K. Masunaga leg.; 7ɗ1Ψ, Kaiolohia Bay, 17.xii.2002, K. Masunaga leg. Maui: 1Ψ, Nahiku, ii.1958, N.L.H. Krauss leg.; 7ɗ27Ψ, Lahaina, 24.xi.1966, T. Saigusa leg.; 1ɗ1Ψ, Hookipa, 10.xii.2002, K. Masunaga leg.; 72ɗ50Ψ, Makena, 10.xii.2002, K. Masunaga leg.; 56ɗ48Ψ, Kahana, 11.xii.2002, K. Masunaga leg.; 87ɗ90Ψ, Little Beach, 12.xii.2002, K. Masunaga leg.; 1ɗ, Hookipa, 12.xii.2002, K. Masunaga leg. Moloka‘i: 108ɗ110Ψ, Waialua, 4.xii.2002, K. Masunaga leg.; 41ɗ20Ψ, Waialua, 5.xii.2002, K. Masunaga leg. O‘ahu: 1ɗ1Ψ, Wawamalu Beach near, Koko Crater, 17.xii.1922, E.H. Brayan Jr. leg.; 1ɗ, Koko Head, 23.vii.1922, E.H. Brayan Jr. leg.; 74ɗ70Ψ, Waianae, 29.v.1966, T. Saigusa leg.; 22ɗ13Ψ, Hanauma Bay, 20.xi.1966, T. Saigusa leg.; 7ɗ17Ψ, Makapu‘u Pt., 5.ii.1967, J.R. Vockeroth leg.; 8ɗ, Makua, 6.ii.1967, J.R. Vockeroth leg.; 1Ψ, Hanauma Bay, 8.iv.1967, J.R. Vockeroth leg.; 1ɗ2Ψ, Makapu‘u Pt., 1.v.1967, J.R. Vockeroth leg.; 3Ψ, Makapu‘u Pt., 6.v.1967, J.R. Vockeroth leg.; 21ɗ11Ψ, Makapu‘u Pt., 21.v.1967, J.R. Vockeroth leg.; 6Ψ, Hanauma Bay, 23.x.1967, J.R. Vockeroth leg.; 31ɗ, Sandy beach park, 19.xii.2002, K. Masunaga leg.; 57ɗ50Ψ, Ulehawa beach park, 20.xii.2002, K. Masunaga leg. French Frigate Shoals: 1ɗ2Ψ, La Perouse Pinnacle, 27.vi.1923, E.H. Brayan Jr. leg.

Distribution. Hawaiian Islands (Hawai‘i, Maui, Läna‘i., Moloka‘i, O‘ahu, and French Frigate Shoals).

Etymology. The name refers to the small size of the adults.

Remarks. This new species most closely resembles Conchopus menehune sp. nov. in having the thickened M1+2 and M1, short setose mid tibia in males, but the male of the latter has the following combination of characters different from those of the new species: mesonotum viewed from above not dark, prescutellar white marking slightly wider, inverted Y-shaped marking without brownish tinge; and setae on anterior surface of fore coxa denser.

Figures

FIGURE 10. Conchopus minutus sp. nov., legs of male: (a) left foreleg in posterior view; (b) distal part of tibia, tarsal segments 1 – 2 of right foreleg in anterior view; (c) left middle femur in anterior view.

FIGURE 11. Conchopus minutus sp. nov., male abdominal sterna: (a) 1 st (top) to 5 th (bottom); (b) pedunculate process in lateral view; (c) sternum 6.

FIGURE 12. Conchopus minutus sp. nov., male genitalia: (a) hypopygium; (b) ventral lobe; (c) cercus; (d) hypandrium in lateral view; (e) hypandrium in dorsal view.

FIGURE 18. Male wings of species of Conchopus: (a) Conchopus acrosticalis (Parent); (b) Conchopus ciliatus sp. nov.; (c) Conchopus crassinervis sp. nov.; (d) Conchopus minutus sp. nov.; (e) Conchopus menehune sp. nov.; (f) Conchopus pacificus sp. nov.