Curtonotum desperatum Klymko & Marshall, 2011

Klymko, John & Marshall, Stephen A., 2011, Systematics of New World Curtonotum Macquart (Diptera: Curtonotidae) 3079, Zootaxa 3079 (1), pp. 1-110 : 91-93

Curtonotum desperatum Klymko & Marshall , sp. n.

Figures 170, 171 , and 172

Etymology. From Latin, desperatus, meaning without hope, referring to the rather desperate nature of the single known specimen, and calling attention to the need for more intensive collecting of Curtonotidae and other lesser known insect families.

Diagnosis. Because of the very greasy state of the single specimen available, colouration and microtomentosity are difficult to assess.

This species can be distinguished from all congeners but C. punctithorax , C. atlanticum , C. papillatum , C. hunkingi , and C. gracile by the combination a dark brown thoracic and abdominal ground colour, extensive infuscation in r 1 and r 2+3, 2 lateral katepisternal setae, yellow-brown legs and clypeus, moderately tall gena (eye height to gena height ratio 11.0) and brown face. Can be presumably be distinguished from C. atlanticum , C. papillatum , and C. hunkingi by its palpi which are dark brown, conspicuously darker than the clypeus, and from those three species plus C. punctithorax by its frons which appears to lack dark brown medial and lateral vittae. Can be distinguished from C. gracile by the darkened apices of its mid and hind femur (this character not present in the two specimens of C. gracile available), its shorter basiphallus, less elongate distiphallus base, and the presence of a recurved lateral process on the left distiphallic lobe.

Description. Based on holotype.

Length: 8.0 mm.

Head: Head of holotype greasy, obscuring true colour of microtomentum. Frons dark brown, with slightly paler medial vitta and green-purple iridescence, especially in lateroventral corner (iridescence visible only from oblique angle), slight bulge ventrally and scattered pale setulae, width 1.3 times height, parallel sided, lateral margin narrowly microtomentose. Ocellar triangle and narrow lateral strip microtomentose, microtomentum of ocellar triangle extending anterior of anterior ocellus, its apical margin an acute point, lateral microtomentose strip extending from median occipital sclerite to ca. quarter distance from proclinate seta to ventral margin of frons. Proclinate seta at ca. two-fifths sagittal distance from anterior ocellus to ventral margin of frons (right proclinate seta missing [including socket] on holotype), anterior to and slightly lateral of major reclinate seta, minor reclinate seta anterior to and medial of major reclinate seta. Face microtomentose, with dark brown ground colour, slightly convex; vibrissa slightly longer than adjacent subvibrissals. Parafacial and gena narrow, microtomentose, ground colour yellow-brown, gena darker posteriorly, eye height 11.0 times gena height. Clypeus with yellow-brown ground colour, microtrichose, palpus and prementum with dark brown ground colour, former microtrichose, surface condition of latter indiscernible due to greasing. Scape and pedicel microtomentose with orange-brown ground colour, first flagellomere densely microtrichose, with orange-brown ground colour on basal ca. quarter, otherwise dark brown.

Thorax: Microtomentum colour largely obscured by greasing, ground colour dark brown. Scutum moderately arched, dark spots present around bases of setulae and setae on at least the scutum, likely elsewhere. Postpronotal lobe with 2 setae, posterior seta knocked off on both sides, on right side a third smaller anterior seta present; notopleuron setulose; scutellum with 2 pairs of marginal setae. Anepisternum with 2 subequal large setae and 4 smaller setae on posterior half; katepisternum with 2 lateral setae, anterodorsal seta much smaller than posterodorsal; linear tuft of setulae under fore coxa dark brown. Area below and behind posterior spiracle bare (without fringe of setulae); minute setulae present on ventral half of meron present.

Legs: Holotype missing right fore and mid leg below the coxae, left fore and mid tarsi and left tarsomeres 2–5, left mid tibia glued onto plastic stage on which specimen is mounted. Colour of microtomentum obscured by grease. Ground colour brown-yellow, mid and hind femur brown on apical ca. tenth and fifth, respectively. Chaetotaxy black except for very dense, regularly spaced transverse rows of setulae anteroventrally on apical half of fore tibia, these dark brown. Fore femur with 6 posterdorsal setae, ctenidial setae 9, only slightly thicker than adjacent setulae; mid femur with 5 anterior setae; hind femur with single subapical dorsal seta. Mid tibia with 2 strong, 2 moderate, and several weak apical ventral setae, 1 moderate seta between the large setae, second weaker moderate seta posterior to the large setae. Row of cuneiform setae absent on entire anteroventral margin of hind (and presumably mid) tarsomere 5.

Wing: As in C. atlanticum except as follows. Wing with grey-brown tinge, costal cell dark brown infuscate.

Abdomen: Holotype abdomen greasy but for small patches on tergites 4 and 5, as such colour of microtomentum and subsequently patterning largely indiscernable. Ground colour dark brown. Tergite 4 grey microtomentose laterally, posterior margin brown microtomentose, not enough microtomentum present to discern lateral or medial vittae. Tergite 5 largely grey microtomentose with broad brown microtomentose medial vitta and brown microtomentum on distal ca. quarter. If lateral vitta present on tergite 5 then very narrow, though preservation of microtomentum too poor to discern this with confidence.

Male terminalia: Sternite 5 with slight invaginate area of weak sclerotization on distal margin, weakly sclerotized area without setulae, posterior margin truncate; tergite 6 moderately sclerotized, desclerotized dorsally; tergite 7 relatively long, dorsal length ca. 0.5 times dorsal epandrial length; sternite 6 and 7 folded over but not broken along protandrial fold, sternite 6 broad, well sclerotized, left portion more heavily sclerotized along proximal margin, right portions of sternite 7 large, nearly as long as adjacent portion of sternite 6. Epandrium relatively small, with large posterolateral lobe (particularly evident in posterior profile), scattered setulae (these longest on posteroventral lobe); surstylus laterally articulating and medially fused to epandrium, broadly rounded posteriorly in lateral profile, posterodorsal corner angular, medial margin (in posterior profile) and ventral face with concavity adjacent to postgonite, minutely setulose laterally on posterior half and ventrally. Cercus stout, with ventral margin flat, longest cercal setulae shorter than longest epandrial setulae. Hypandrium with broad-based, proximally rounded and distally tapering dorsobasal lobe, posterior bridge slightly produced ventrally and anteriorly, arm bent dorsally within epandrium, with 1 ventromedially and 1 ventrally oriented setula proximal to postgonite, ventrally oriented setula more distal, broadly fused apically to opposite hypandrial arm; postgonite occluded by surstylus in lateral profile, minutely setulose dorsally at apex, with cleft in posterior margin. Phallapodeme with relatively large, anteriorly bulging “fan”, margin opposite fan convex basally, concave distally; basiphallus very elongate, weakly sclerotized basally, with subapical ventral bulge, bending slightly to right then to left (hence lateral margins parallel) distal of bulge; distiphallus base relatively straight and elongate, tapering apically in dorsal profile, bowing slightly dorsally in lateral profile, apex bilobed, left lobe nearly perpendicular to axis of phallus basally, distal two-thirds posteriorly bent, longer than right, with forward facing, spinose moderately sclerotized process on lateral margin, ventral half well sclerotized ventrally, smooth, lightly sclerotized dorsally, with elongate erect spinules, distal half moderately sclerotized throughout, smooth dorsally, ventrally with broad-based, short, antrorse spinules, apex rounded, right lobe straight, moderately sclerotized dorsally (especially medially), weakly sclerotized ventrally, with pebbled texture throughout, left basal corner with short fine spinules swept to left, apex rounded. Ejaculatory apodeme outside of basiphallus, elongate, pointed apically, with small pores on basal two-thirds.

Female terminalia: Unknown.

Type material. Holotype: ♂: BRAZIL. “59.57 Vigors Coll.” ( BMNH).

Figures

FIGURES 170–172. Curtonotum desperatum Klymko & Marshall, sp. n. 170. Male terminalia, left lateral. 171. Male terminalia, posterior. 172. Distiphallus, dorsal.