Enlinia dalensi, Runyon & Pollet, 2018

Runyon, Justin B. & Pollet, Marc, 2018, Enlinia Aldrich, 1933 of Mitaraka, French Guiana (Diptera: Dolichopodidae), Zoosystema 40 (19), pp. 453-468 : 464-466

Enlinia dalensi n. sp.

( Figs 11 , 12 )

urn:lsid:zoobank.org:act:F079FB9D-54F0-4458-B515-9E3AEA024AF1

TYPE MATERIAL. — Holotype. ♂, slide mounted. First label: “GUY-ANE, Maripasoula, N 2°13’59.8” / W 54°27’46.5”, 471m, Malaise trap (6m), 13.viii.2015 - 20.viii.2015, P.-H. Dalens leg.” Second label: “partially open areas on savane roche 2; La Planète Revisitée Guyane 2015, MNHN PNI, sample cd: MITARAKA/230”. Third label: “ HOLOTYPE ♂ Enlinia dalensi Runyon & Pollet 2018 ” (red label). Deposited at MNHN.

ETYMOLOGY. — This species is named in honor of, and out of respect to, Pierre-Henri Dalens, président de la Société entomologique Antilles-Guyane (SEAG), who led the Mitaraka entomological team during periods 2 and 3 of the expedition. Thanks to him, the 6 m Malaise trap was installed on ‘savane roche 2’ which led to the discovery of an unprecedented rich Enlinia fauna on this rocky outcrop.

DIAGNOSIS. — Enlinia dalensi n. sp. can be recognized by the form of the modified fore tarsus ( Fig. 11A ), the ventral setae on middle femur ( Fig. 11C ), the shape of the wing and wing veins ( Fig. 12 ), and modifications of abdominal sternites ( Fig. 11D, E ). This species is closely related and quite similar to E. bredini Robinson, 1975 from Dominica, to which it keys in Robinson (1975). Both species have similarly modified fore tarsi ( Fig. 11A ), similar modifications in shape and armature on abdominal sternites 3 and 4 ( Fig. 11D, E ), and similar blunt setae on middle femur ( Fig. 11C ), among other characteristics. Enlinia dalensi is most readily distinguished by a distinctly sinuous wing vein R 4+5 that is bent backwards at apex (straight in E. bredini ), a wing with a less sinuous posterior margin, and larger anal area, and epandrial lobes that lack plumose hairs and feature large prong or hook on inner surface near base.

DESCRIPTION

Male

Body size. Length. 0.9 mm, wing length 0.9 mm by 0.4 mm (width).

Head. Face very narrow on ventral half but still distinct to mouth; anterior facets distinctly enlarged. Upper face and frons dark brown. Palpus small, yellow, nearly round with anterior surface truncate and fringed with minute black hairs; proboscis brown. Antenna brown; first flagellomere very short and blunt, about twice as wide as long; arista-like stylus apical, about 1.5 times as long as face.

Thorax. Scutum dark brown with weak violet reflections, pleura brown. Setae brown with pale reflections; 6-7 pairs of small acrostichal setae; 7-8 pairs of dorsocentral setae; one pair of widely separated scutellar setae.

Legs. Yellow with coxae brownish, with dark setae. Fore coxa with a large seta on inner anterior surface near apex. Mid trochanter ( Fig. 11C ) with long black ventral seta (in line with row of ventral setae on mid femur). Fore femur ( Fig. 11B ) with a slender erect ventral seta at base (length subequal to width of femur) and anteroventral row of about 10 minute peg-like setae on apical half; mid femur ( Fig. 11C ) with ventral row of 4 large setae on basal half which become larger towards base of femur, these setae blunt apically except basal-most seta which is normal (sharply pointed); femur thickest at insertion of basal-most setae. Fore tibia with ventral surface slightly flattened; mid tibia with a brush of very short, erect ventral setae on apical 1/3; hind tibia gradually and slightly widened toward apex, with a dorsal seta near base, a smaller dorsal seta near 1/3, and a larger dorsal seta near apex. Fore tarsus ( Fig. 11A ) highly modified, tarsomere 1 broad with 2 dorsal setae near apex; tarsomere 2 apically projecting alongside and partly overlapping tarsomere 3 with two lobes near apex and ventrally with a small darker, more sclerotized area that includes a minute spicule; tarsomere 3 long and slender, slightly bent just before middle, with large arched dorsal seta near middle; tarsomere 4 short, rounded to heart-shaped, arising from near middle of tarsomere 3; tarsomere 5 expanding from a very narrow base. Ratios of tibia:tarsomeres for fore leg: 10-4-4-4-2-4; for mid leg: 12- 6-3-2-2-3; for hind leg: 16-6-4-3-2-3.

Wing ( Fig. 12 ). Elliptical with hind margin slightly sinuous and nearly straight basad to apex of CuA 1, long-fringed with hairs; hyaline. Vein R 2+3 close to and parallel with costa on about basal half, curving slightly towards vein R 4+ 5 in distal half before curving slightly forward to costa; vein R 4+5 mostly straight but distinctly curving backwards at apex; vein M 1 slightly sinuous beyond crossvein, curving slightly forward at apex; crossvein dm-cu about half as long as apical part of vein CuA 1; vein CuA 1 not reaching wing margin, slightly bowed beyond crossvein; vein A 1 represented by indistinct thickening along anal margin. Halter brown.

Abdomen ( Fig. 11D, E ). Brown, with very sparse, short brown setae.Sternite 3 more strongly sclerotized laterally and less so medially and apically, with minute median armature at hind margin; sternite 4 highly modified, medially divided into pair of C-shaped lobes with a brown setiferous papilla at each hind corner that is projecting posteroventrally. Hypopygium small, brown, capping tip of preabdomen; cerci very small, slightly longer than wide with small marginal hairs; epandrium with thin, nearly transparent, tapering lobes that project forward beneath abdomen and between papillae of sternite 4.

Female

Unknown.

REMARKS

The setiferous papillae on abdominal sternite 4 in males of E. dalensi n. sp. ( Fig. 11D, E ) appear homologous to the “brown projection composed of a loop of twisted, finely striate chitin” of E. bredini ( Robinson 1975: 47) . We have seen an undescribed species from Dominica that belongs to the species group containing E. bredini and E. dalensi n. sp. and possesses a similarly modified fore tarsus, ventral setae on middle femur, and shape of the wing and modifications on abdominal sternites. Enlinia anomalipennis Robinson, 1969 from Mexico, also appears to belong to this group based on the similarly modified fore tarsus, ventral setae on middle femur, and shape of the wing and hypopygium.

OTHER SPECIMENS

A female specimen representing a seventh Enlinia species occurring at Mitaraka was taken during the expedition (‘sp. GF-007’). This specimen belongs to the distinct E. armata group whose members possess a row of very short ventral setae on the fore femur and strong dorsal setae on the hind tibia in both sexes ( Robinson 1969) but cannot be confidently assigned to any of the described species. Although this species is likely new, males will need to be collected before it can be formally described. This specimen is briefly characterized below.

Specimen examined

Enlinia ‘sp. GF-007’, one female, “ GUYANE, Maripasoula, N 2°14’11”, W 54°27’07”, 306 m, Malaise trap (6 m), 25.VIII.2015, river, J. Touroult, E. Poirier leg.” Second label: “tropical wet forest, La Planète Revisitée Guyane 2015, MNHN PNI, sample cd: MITARAKA/189”. This specimen is deposited at MNHN.

Body size 1.2 mm. Antenna, thorax, abdomen and legs brown with brown setae and hairs. Scutum with 4-5 pairs of acrostichal setae; six pairs of dorsocentral setae. Fore femur with anteroventral row of small setae that get stouter and slightly longer towards apex of tibia; with two posteroventral setae near apex. Fore tibia with dorsal seta near 1/3 and one dorsal row of short, closely-spaced setae (length about half width of tibia) along nearly full-length. Mid tibia with 2 dorsal setae near 1/4, one seta at 1/2, and one near apex; with one larger ventral seta at apex. Hind tibia with one anterodorsal seta at 1/4, at 1/2, and near apex; with one row of five rather stout posterodorsal setae along full-length of tibia; with one ventral seta at apex. Wing narrowly oval and with slight brown tinge and evenly rounded margins; veins nearly straight and evenly diverging from base. Halter brown.

Figures

FIG. 11. — Enlinia dalensi n. sp., ♂: A, tip of fore tibia and tarsus, dorsal view; B, fore femur, anterior view; C, mid trochanter and femur, posterior view; D, tip of abdomen and terminalia, right lateral view; E, tip of abdomen and terminalia, ventral view. Abbreviations: cerc, cerci; S3, abdominal sternite 3; S4, abdominal sternite 4. Scale bars: 0.25 mm.

FIG. 12. — Enlinia dalensi n. sp., ♂ wing. Scale bar: 0.5 mm.