Curtonotum atlanticum Klymko & Marshall, 2011

Klymko, John & Marshall, Stephen A., 2011, Systematics of New World Curtonotum Macquart (Diptera: Curtonotidae) 3079, Zootaxa 3079 (1), pp. 1-110 : 93-97

publication ID	https://doi.org/ 10.11646/zootaxa.3079.1.1
persistent identifier	https://treatment.plazi.org/id/8F1187DF-681D-FFAC-FF38-F9CCFBB8FE59
treatment provided by	Felipe
scientific name	Curtonotum atlanticum Klymko & Marshall
status	sp. nov.

Treatment

Curtonotum atlanticum Klymko & Marshall View in CoL , sp. n.

Figures 173–179 View FIGURES 173–179

Etymology. The specific name is in reference to the Atlantic forest, the only known habitat of this species.

Diagnosis. Distinguished from congeners but C. papillatum , C. hunkingi , C. punctithorax , and possibly C. desperatum (this species is included here due to the degraded state of the only specimen available) by its orange-yellow frons with prominent brown medial and lateral vittae. To distinguish this species from the latter two species see their diagnoses. To distinguish this species from C. papillatum and C. hunkingi see comments section below.

Description. Length: 7.5–8.3 mm.

Head: Frons orange-yellow with prominent dark brown medial and lateral vittae and faint blue-green iridescence (visible only from oblique angle), medial vitta narrow, diffuse at dorsal and ventral ends, lateral vittae between medial vitta and orbital setae, convergent and much more strongly pigmented ventrally; frons with moderate bulge ventrally and scattered pale setulae, width 1.2–1.4 times height, slightly narrower ventrally, lateral margin silver microtomentose. Ocellar triangle and narrow lateral strip gold microtomentose, microtomentum of ocellar triangle extending anterior of anterior ocellus, anterior margin rounded or acutely pointed, lateral microtomentose strip extending from median occipital sclerite to slightly anterior of proclinate seta. Proclinate seta ca. one-quarter to one-third sagittal distance from anterior ocellus to ventral margin of frons, anterior to and slightly lateral of major reclinate seta; minor reclinate seta anterior to and medial of major reclinate seta. Face silver microtomentose, ground colour pale brown-yellow, facial carina often with darker ground colour; vibrissa ca. twice as long as adjacent subvibrissals. Parafacial and gena moderately broad, former silver microtomentose with pale orange-yellow ground colour, latter yellow-brown microtomentose with brown ground colour, eye height 6.4–10.7 times gena height. Clypeus silver microtomentose, with orange-yellow ground colour; palpus silver microtrichose, ground colour slightly darker than clypeus; prementum medium to dark brown, sparsely silver microtomentose laterally. Scape and pedicel silver microtomentose with orange-yellow ground colour; first flagellomere silver microtrichose, with orange ground colour on proximal ca. third to half, otherwise orange-brown.

Thorax: Ground colour medium to dark brown, scutum light brown microtomentose; scutellum dark brown microtomentose medially, light brown microtomentose laterally; pleuron purple-grey microtomentose. Scutum moderately arched, each scutal, postpronotal, and anepisternal seta and setula with dark brown spot around socket. Scutum with 2 pairs of narrow vittae, these visible only near posterior margin, their anterior margin at ca. midpoint between posterior scutal margin and transverse suture. Postpronotal lobe with 3 setae, center seta ca. 0.75 times length of posterior seta, anterior seta much smaller, sometimes additional small seta present posterior to these; notopleuron setulose or bare; scutellum with 2 pairs of marginal setae. Anepisternum with 2 strong and 2–4 moderate setae on posterior half; katepisternum with 2 prominent lateral setae, anterodorsal seta weaker than posteroventral seta; linear tuft of setulae under fore coxa orange-yellow. Area below and behind posterior spiracle bare (without fringe of setulae); minute setulae on ventral half of meron present.

Legs: Coxae densely silver microtomentose, legs otherwise lightly so. Chaetotaxy black except for very dense, regularly spaced transverse rows of setulae anteroventrally on apical half of fore tibia and similar setulae on fore tarsomere 1, these medium brown. Legs with brown-yellow ground colour, all tibiae, femora, and tarsomeres 1 and 2 dark brown at apex, tarsomeres 3–5 dark brown throughout (specimens from Teresopolis, Brazil, with relatively dark tibiae and femora). Fore femur with 4–6 posterodorsal setae, 6–7 ctenidial setae, these relatively thick and subequal in length to adjacent setulae; mid femur with 4–6 anterior setae; hind femur with single subapical dorsal seta. Mid tibia with 2 strong, 1 moderate and several weak apical ventral setae, the moderate seta between the strong setae. Row of cuneiform setae present on proximal third to entire anteroventral margin of mid tarsomere 5 and proximal ca. two-thirds of hind tarsomere 5.

Wing: Alula relatively broad. Non-infuscated areas of wing with yellow to yellow-brown tinge. Costal cell dark to medium brown infuscate, r 1 dark brown infuscate, infuscation paler and yellower distal of costal cell (as in Figure 218 View FIGURES 210–218 ), the size of this pale area varying somewhat between specimens (in specimens from Teresopolis, Brazil, r 1 is dark brown infuscate throughout); r 2+3 dark brown infuscate on anterior half, infuscation starting distal of r-m (as in Figure 218 View FIGURES 210–218 ) (in specimens from Teresopolis, Brazil, area of infuscation starts at level of r-m), pale brown in broad distal area; membrane around crossvein dm-cu narrowly brown infuscate.

Abdomen: Ground colour dark brown, grey microtomentose except where noted. Tergite 2 brown microtomentose dorsally on posterior ca. third; tergite 3 brown microtomentose dorsally on posterior ca. half to quarter, with medial and lateral brown microtomentose vittae, grey microtomentose to posterior margin lateral of lateral vitta; tergite 4 similar to tergite 3 but narrowly brown microtomentose along posterior margin lateral of lateral vitta; tergite 5 similar to tergite 4 but brown microtomentose dorsally only on posterior sixth to third. In tergites 3–5 the grey maculae isolated by the lateral and medial vittae fainter than other area of grey microtomentum on the abdomen, and with a purple cast.

Male terminalia: Sternite 5 with invaginate area of weak sclerotization on distal margin, weakly sclerotized area setulose, posterior margin truncate; tergite 6 weakly to moderately sclerotized, desclerotized dorsally; tergite 7 relatively long, dorsal length ca. 0.6 times epandrial dorsal length; both sternite 6 and 7 well separated into right and left portions, right and left portion of sternite 6 broad and well sclerotized, left portion more heavily sclerotized proximally; right portion of sternite 7 a well-sclerotized relatively broad band, only slightly shorter than right portion of sternite 6. Epandrium moderately large, with large posterolateral lobe (particularly evident in posterior profile) and scattered setulae (in no area are these particularly long); surstylus laterally articulating with and medially fused to epandrium, nearly quadrate in lateral profile, distomedial corner angular and slightly recurved, medial margin concave in posterior profile, with minute setulae dorsally and ventrally, area adjacent to postgonite concave. Cercus stout, with ventral margin flat or slightly concave, longest cercal setulae subequal to longest epandrial setulae. Hypandrium with broad-based and broadly rounded dorsobasal lobe, posterior bridge ventrally produced, arm relatively straight, with 2–3 ventromedially oriented setulae proximal to postgonite, broadly fused distally to opposite hypandrial arm; postgonite narrowing distally, medial margin with broad medial process abutting with adjacent postgonite, with small cleft in lateral profile on distal margin, minutely setulose dorsally, obscured by surstylus in lateral profile. Phallapodeme with relatively small, anteriorly bulging “fan”, margin opposite fan convex basally, concave distally; basiphallus very elongate, weakly sclerotized basally, straightening slightly distally in lateral profile, with subapical concavity on left in posterior profile and slight to moderate apical bulge; distiphallus base elongate, broad and dorsoventrally flattened on proximal two-thirds, bowed dorsally in lateral profile, Sshaped in dorsal profile, narrowing distally, apex bilobed, left lobe slightly longer, nearly perpendicular to axis of phallus basally, apical two-thirds bent posteriorly, with recurved process on left lateral margin at bend, dorsal surface heavily sclerotized medially, sclerotization extending to ca. midpoint, moderately sclerotized on proximal half of lateral margin, lobe otherwise lightly sclerotized, ventral surface with very broad base spinules, apex broadly rounded; right lobe in same axis as phallus, straight, moderately sclerotized and with fine pebbled texture ventrally, with broad moderately sclerotized region dorsally, short stout spinules dorsally and fine elongate spinules on right and left, apex broadly rounded. Ejaculatory apodeme outside of basiphallus, rod-shaped, with small pores on basal ca. two-thirds.

Female terminalia: Ovipositor slender and elongate (as in Figure 202 View FIGURES 195–202 ). Sternite 5 length 1.6–1.8 times width, sternite 6 length ca. 1.1–1.2 times width, tergite 6 desclerotized medially on proximal half, tergite 7 desclerotized medially. Tergite 8 and sternite 8 weakly sclerotized proximally. Sternite 8 nearly truncate apically, distal third heavily sclerotized, especially marginally, area of heavy sclerotization without microtrichia or setulae. Sternite 10 heavily sclerotized and with antrorse spinules medially, area of sclerotization flaring proximally, proximal margin with slight dorsal bend, profile narrow on proximal half, broader on distal half. Spermatheca elongate, surface with moderate ridges, in some specimens these forming protuberances. Ventral receptacle flared basally, neck heavily sclerotized with concave margins, apex lightly sclerotized, hemispherical, duct finely wrinkled longitudinally.

Comments. Curtonotum hunkingi , C. atlanticum and C. papillatum can only be identified with confidence through the examination of male genitalia. While slight differences exist in the range of head dimensions and seta numbers given in the descriptions, there is so much interspecific overlap and intraspecific variability that these characters are not diagnostic. Some external characters that may be of use for distinguishing these species are discussed here, but, given the very limited number of localities for each species, the variability within each is not well known. Specimens available do show differences in the spermathecae and ventral receptacles, but it is likely that the full range of variation within these structures is not represented in the small number of specimens available (e.g. only one specimen in C. hunkingi and four in C. atlanticum [one of these left undissected]), and therefore caution should be used when identifying female specimens not associated with males.

The frontal vittae are less well defined (the medial vitta is often absent) and less pronounced ventrally in C. papillatum than in the other two species. The anterior margin of the ocellar triangle microtomentum is always acutely pointed in C. papillatum ; this condition is present in some C. atlanticum specimens and none of the C. hunkingi specimens. The extent of the scutal vittae is also variable between these species. In C. atlanticum both pairs of vittae extend from the posterior margin to the midpoint between posterior margin and transverse suture. In C. papillatum the extent of the medial pair is variable, in some specimens they extend to the level of the postpronotal lobe, in others they are as limited as in C. atlanticum ; the lateral pair extends nearly to the transverse suture. In C. hunkingi the medial pair extends to level of postpronotal lobe, but the lateral pair is as limited as in C. atlanticum (as mentioned in description, this is based on a single specimen). However, in all three of these species these vittae are very faint, especially anteriorly, and therefore can be difficult to assess. The relative extent of cuneiform setae appears to vary between species, with C. hunkingi having the most, C. papillatum having the least, and C. atlanticum falling somewhere between, but there is much overlap in the specimens examined, and the extent of overlap will likely increase as more specimens become available.

Curtonotum atlanticum females can be distinguished from C. papillatum and C. hunkingi by the ventral receptacle which lacks the bulbous head found in the latter two species. Curtonotum papillatum females can be distinguished from C. hunkingi by their densely papillose spermatheca without any rugae and a ventral receptacle with a longer and more heavily sclerotized neck (relative to the head).

Male C. papillatum can be most easily distinguished from C. atlanticum and C. hunkingi by the more elongate basiphallus and straight and slender distiphallus base (compare Figures 187 and 189 View FIGURES 187–190 to Figures 173 and 175 View FIGURES 173–179 , and 181 and 182). Curtonotum atlanticum can be distinguished from C. hunkingi by the basally broad and dorsoventrally flattened distiphallus (compare Figures 173 and 175 View FIGURES 173–179 with Figures 181 View FIGURES 180–186 , and 182).

Type material. Holotype: ♂: BRAZIL. São Paulo: Campos do Jordão , i.1948, F. Lane ( MZSP) . Paratypes: BRAZIL. Rio de Janiero: ♂, Itatiaia, Maromba , i.1948, C. d’Andretta ( MZSP) ; ♂, ♀, Teresópolis, Parque Nacional da Serra dos Órgãos , 1300–1700 m, trail to Pedra do Sino , 25.i.1990, S.A. Marshall ( DEBU) . São Paulo: ♂, ♀, Campos do Jordão , 4.i.1936 , ♂, 6.i.1936, 2♂, ♀, i.1948, all F. Lane ( MZSP) .