Curtonotum Macquart, 1844: 350

Klymko, John & Marshall, Stephen A., 2011, Systematics of New World Curtonotum Macquart (Diptera: Curtonotidae) 3079, Zootaxa 3079 (1), pp. 1-110 : 18-24

publication ID	https://doi.org/ 10.11646/zootaxa.3079.1.1
persistent identifier	https://treatment.plazi.org/id/8F1187DF-6850-FFDB-FF38-FCB8FE54F88B
treatment provided by	Felipe
scientific name	Curtonotum Macquart, 1844: 350
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Treatment

Curtonotum Macquart, 1844: 350 View in CoL View at ENA (193)

Type species: Musca gibba Fabricius, 1805 [preoccupied], by original designation. [The name of the type species is a junior primary homonym preoccupied by Musca gibba Müller, 1776 and M. gibba Rossi, 1794 . Curtonotum taeniatum Hendel,

1913: 629 was accepted as the replacement name by Thompson and Pont (1994)]. Cyrtonotum Agassiz, 1846: 108 , 114. (Unjustified emendation of Curtonotum Macquart ) Diplocentra Loew, 1862: 13 . ([unnecessary] new replacement name for Curtonotum Macquart ). Seliacantha Bezzi, 1895: 66. Nomen nudum, attributed to Rondani and proposed in synonymy (with Diplocentra Loew, 1862 ).

Name from a collection label. Also Bezzi (1902: 192). Selidacantha Bezzi, 1895: 66 . Nomen nudum, proposed as an emendation of the likewise unavailable Seliacantha Bezzi, 1895:

66. Also Bezzi (1902: 192).

Description of genus. Moderate to large (5–11 mm); grey, yellow, brown, or purplish to black; moderately to distinctively robust, hump-backed, drosophilid-like flies ( Figures 6–13 View FIGURES 6–7 View FIGURES 8–9 View FIGURES 10–11 View FIGURES 12–13 ).

Head: 1.3–1.7 times as high as long; width 1.7–2.1 times frons width. Frons quadrate to 1.5 times wider than high, edges parallel to slightly broader dorsally to slightly broader ventrally, flat to strongly bulging ventrally. 1 strong reclinate seta (major reclinate seta) inserted below level of anterior ocellus, 1 slightly weaker proclinate seta inserted anterior to the reclinate seta, its relative position varying between species, 1 very small reclinate seta (minor reclinate seta) between these 2 setae. Inner and outer vertical setae strong, ocellar setae subequal to outer vertical and major reclinate seta, postocellar setae weaker ( Figure 38 View FIGURES 38–39 ). Occiput densely microtomentose, microtomentum extending to proclinate seta and generally onto and often anterior to ocellar triangle ( Figure 190 View FIGURES 187–190 ) (frons microtomentum is absent or very limited in several species in the C. vulpinum species complex). Frons otherwise with dull sheen and often iridescent, variously marked, and in most species with microtomentose lateral margins. Face pale yellow to nearly black, moderately to densely microtomentose, facial carina flat in lateral profile, sometimes bare and shiny medially ( Figure 69 View FIGURES 66–69 ), this varying within and between species. Parafacial densely microtomentose, narrow to very broad, width varying between species. Gena moderately to densely microtomentose, similarly variable in height, often appearing duller than gena due to minute scaled texture, eye height ca. 3–20 times genal height (see Figures 26 View FIGURES 26–27 and 69 View FIGURES 66–69 for examples of variability). Vibrissa absent or weak to moderately strong, 9–12 very weak to weak subvibrissal setulae present. Eye bare. Prementum densely microtomentose; palpus with dense fine microtrichia, pale yellow to very dark brown, elongate, slightly broader apically, weakly to moderately upcurved (this varying within species), with scattered lateral setulae; prementum bare and glossy to densely microtomentose, with scattered setulae. Antennae relatively short, appressed on face, scape densely microtomentose, short and stout; pedicel densely microtomentose, with anterior margin bulging and distinct dorsal seam; first flagellomere with fine microtrichia, ca. twice as long as wide; arista basally inserted, with ca. 12 dorsal and 6 ventral elongate rays, ray numbers varying within species.

Thorax: Densely microtomentose and dull to moderately microtomentose and subshining. In all species, but those in the Curtonotum vulpinum species complex ( Figure 12 View FIGURES 12–13 ), C. impunctatum ( Figure 13 View FIGURES 12–13 ), C. curtispinum , C. helvum ( Figure 6 View FIGURES 6–7 ) and C. floridense , each scutal, postpronotal, and anepisternal seta and setula with dark spot around socket, as if each seta and setula is greasy and has stained the otherwise frosty thorax ( Figures 7–11 View FIGURES 6–7 View FIGURES 8–9 View FIGURES 10–11 ). Scutum moderately to very strongly arched (see Figures 8 View FIGURES 8–9 and 12 View FIGURES 12–13 for examples of variability), unmarked or with faint to strong parallel vittae; densely setulose. 2–3 postpronotal, 2 notopleural, 1 presutural supra-alar, 2 postsutural supra-alar, 1 postsutural intra-alar, 2 postsutural dorsocentral and 1 prescutellar acrostichal setae present. Notopleuron variously setulose. In some species several setae near wing base approach length of postsutural supra-alars. Scutellum relatively flat, setulose on disc, with 2–3 pairs of strong marginal setae, lateral seta strongest, followed by medial and then (when present) the third seta falling between the 2. Single weak proepisternal seta present. Anepisternum with 3–5 moderate to strong posterior setae and scattered setulae on posterior half. Katepisternum with 1 strong and usually 1 weaker seta, stronger seta posteroventral to weaker seta, otherwise with scattered setulae on ventral half, row of weak setulae anterior to mid coxa, 1–3 stronger setae at posteroventral corner, and dense linear tuft of setulae under mid section of fore coxa. In some species posterior spiracle with several setulae ventral and posterior to spiracle’s dense fringe of fine pale setulae ( Figure 109 View FIGURES 106–109 ). In some species meron with minute scattered setulae on ventral half.

Wing: Varying from nearly hyaline to heavily infuscate and boldly patterned ( Figures 203–218 View FIGURES 203–209 View FIGURES 210–218 ). Costa with humeral and subcostal breaks, extending to apex of R 4+5, strongly spinose between R 1 and R 2+3 (in C. curtispinum these spines are greatly reduced [ Figure 212 View FIGURES 210–218 ]); subcosta complete; crossvein bm-cu absent; A 1 weak, represented by fold not reaching wing margin; cell cu p present; alula width variable between species; crossvein dm-cu distal of the apex of R 1 in all New World species, but those in the C. vulpinum species complex (where it is directly posterior to or anterior of the apex of R 1) and C. helvum , C. floridense , C. impunctatum and C. curtispinum (where it posterior to the apex of R 1). Lower calypter usually narrow, but greatly expanded in the C. murinum species complex; upper calypter narrow. Halter yellow-white.

Legs: Relatively long and slender, variously coloured, tibia and femora often darker toward apices. Fore coxa reaching or nearly reaching mid coxa (some species in the C. vulpinum species complex have the fore coxa much shorter, extending as little as 0.6 times the distance between fore coxa socket and mid coxa socket). Fore coxa with 2 moderate apical setae and scattered setulae; mid coxa with 2 strong lateral and several moderate medial setae and scattered medial setae; hind coxa with 1 moderate lateral seta and scattered setulae. Fore femur with 3–7 posterodorsal setae, proximal seta generally well separated from others, 5–6 larger setulae along apical posteroventral margin, most species with well-defined ctenidial comb of 5–12 medium length to short and stout setae. Mid femur with 4–12 anterior setae on distal two-thirds (number varying within and between species) and 2 strong apical setae (1 anterior, 1 posterior). Hind femur with 1 or 2 subapical dorsal setae (number varying within and among species). Fore tibia with subapical dorsal seta and very dense, regularly spaced transverse rows of setulae anteroventrally on apical half. Mid tibia with subapical dorsal seta and several apical ventral setae on ventral margin, their number and relative strength varying between species. Hind tibia with sub-apical dorsal seta, 1 weak anterior apical seta and several very small apical ventral setae, and very dense, regularly spaced transverse rows of setulae posteriorly on apical eighth. Fore tarsomere 1 with very dense, regularly spaced transverse rows of setulae anteroventrally on entire length, several larger ventral setae on apical fifth, and small anterior and posterior apical setae. Fore tarsomeres 2–5 with small anterior and posterior apical setae and 2 ventral rows of relatively stout setae. Mid tarsomere 1 with 2 rows of widely spaced moderately long and stout setae for entire length, anteroventral and posteroventral margins with very tightly spaced row of short cuneiform setae. Mid tarsomeres 2–5 with very tightly spaced row of short cuneiform setae on anteroventral and posteroventral margins as in those of fore tarsus, the row of setulae on the anteroventral margin of tarsomere 5 partially to completely absent in some species. Hind tarsomeres 1 and 2 each with very dense, regularly spaced transverse rows of setulae anteroventrally on entire length, these setulae much longer than those of the transverse rows on the fore tarsus; very tightly spaced row of short cuneiform setae on anteroventral margin, and small, anterior apical seta. Hind tarsomeres 3–5 as in those of fore tarsus, the row of short cuneiform setulae on the anteroventral margin of tarsomere 5 partially to completely absent in some species.

Abdomen: Cylindrical, somewhat tapered apically, variously patterned, dark species usually with patterning a result of micrtomentum (not visible in greasy or cleared specimens); paler species usually with pattern of pigmentation on sclerites (usually visible even in greasy or cleared specimens). Tergite 1 relatively narrow, with scattered setulae, tergite 2 with lateral row of strong setae on proximal half, bare anterior to this, otherwise with short scattered setulae throughout and longer setae along posterior margin ( Figure 109 View FIGURES 106–109 ). Sternites 3–5 with short scattered setulae throughout and longer setae along posterior margin. Sternite 1 very small and narrow, sternites 2–5 of various relative widths; in some species male sternite 5 modified either with an apical emargination, protuberance or specialized chaetotaxy ( Figures 17 View FIGURES 17–19 , 72 View FIGURES 70–72 , 92 View FIGURES 90–93 , 125 View FIGURES 122–125 , and 141). Single pair of well-spaced sensory setulae near anterior margin of sternites 1–5, spiracles 1 through 5 in margin at approximate midpoint of each segment.

Male terminalia: Tergite 6 a dorsal band, varying among species from well defined and setulose to completely atrophied. Sternite 6 moderately to well sclerotized, often divided along ridge in protandrium, left portion a narrow to broad band, with single sensory setulae, fused to left portion of sternite 7, area of fusion demarked by suture free of microtrichia, right portion broad, triangular, with single sensory setula (this sensory setula sometimes in margin just anterior to sclerite). Sternite 7 usually split along protandrial ridge, left portion with single sensory setula, quadrate, fused ventrally to left portion of sternite 6 and dorsally to tergite 7, both areas of fusion demarked by suture free of microtrichia, right portion a narrow to broad band anterior and fused to right portion of sternite 6, area of fusion demarked by seam, with single sensory setula. Tergite 7 moderately to strongly sclerotized, varying in length. Spiracles 6 ventral to tergite 6, spiracle 7 slightly reduced in size, slightly posterodorsal of spiracle 6, on left anterior to syntergosternite 6+7 (sternite 6 + sternite 7 + tergite 7). Tergite 8 and sternite 8 lost, along with associated sensory setulae and spiracles. Hypandrium U-shaped, symmetrical, posterior transverse portion (posterior bridge) articulating with phallapodeme, lateral extensions (hypandrial arms) extending posteriorly, with 2–3 ventrally oriented setulae on each arm ( Figures 14 and 16 View FIGURES 14–16 ). Postgonite fused to hypandrium, suture discernable in some species, entirely fused in others. Epandrium saddle-shaped, setulose, often with elongate setae distoventrally. Surstylus freely articulating with, or partially fused to, epandrium ( Figure 14 View FIGURES 14–16 ). Cerci separate from each other and from epandrium ( Figures 40 and 42 View FIGURES 40–42 ) (except in C. helvum , C. floridense and most Old World species where cerci are fused ventrally, forming a bulbous arm [ Figures 14 View FIGURES 14–16 and 17 View FIGURES 17–19 ]). Subepandrial sclerite X-shaped in C. helvum , ventral and dorsal arms fusing to surstyli and posterior part of epandrium, respectively, anteriorly fusing to bridge connecting hypandrial arms ( Figure 30 View FIGURES 28–31 ). Phallapodeme with broad “fan” laterally flattened in Neotropical species (e. g., Figure 40 View FIGURES 40–42 ), with basal lateral lobes in the two Nearctic species ( Figures 14 View FIGURES 14–16 and 29 View FIGURES 28–31 ), articulating with hypandrium proximally, extending distally in long bent rod invaginated by, and broadly fused to, basiphallus. Basiphallus elongate, tubular, C-shaped, symmetrical except at apical junction with distiphallus. Distiphallus asymmetrical, freely articulating with basiphallus except in C. flavisetum and C. impunctatum , where the basiphallus and distiphallus are completely fused, apex in most species with 2 variously proportioned and ornamented lateral lobes. Ejaculatory apodeme elongate, outside or just inside of basiphallus, with minute pores varying in distribution between species.

Female terminalia: Ovipositor relatively stout to slender and elongate (compare Figures 32 View FIGURES 32–37 and 202 View FIGURES 195–202 ). Tergites 6 and 7 well sclerotized, setulose; some species with varying degrees of medial desclerotization in tergite 6 or 7. Sternites 6 and 7 well sclerotized, of varying widths, with setae scattered throughout and longer setae along apical margin. Spiracles 6 and 7 present, in membrane in anterior portion of segments 6 and 7, respectively. Sternite and tergite 8 with scattered short setulae and varying degrees of sclerotization, the anterior margin in many species indiscernible. Sternite 8 very heavily sclerotized posteriorly in many species, often forming a slightly concave distal lip devoid of setulae and microtrichia. Sternite 10 in most New World species flattened dorsoventrally, the anterior half or more relatively narrow with slightly thickened, dorsally bent anterior margin, strongly sclerotized median, and broad, setulose apical half, proximal half with large posterior-facing unsocketed spinules over thickened median, otherwise with fine posterior-facing microtrichia and scattered small setulae ( Figure 63 View FIGURES 62–65 ). In C. bathmedum , C. bivittatum , and C. curtispinum the narrow anterior portion of sternite 10 is much reduced ( Figures 47 View FIGURES 46–50 , 54 View FIGURES 51–57 , and 103), while in C. trypetipenne and C. apicale it is relatively narrow, heavily sclerotized throughout, and without spinules or microtrichia ( Figures 79 View FIGURES 77–81 and 88 View FIGURES 82–89 ). Curtonotum helvum and C. floridense are unique among New World species in having sternite 10 deeply invaginate apically, this invagination extending anteriorly into an elongate, laterally flattened, well-sclerotized, spinule and microtrichia-free anterior portion ( Figures 22 View FIGURES 20–25 and 35 View FIGURES 32–37 ). Tergite 10 free, well defined, and with microtrichia and setulae in some species and fused to the cerci, mostly atrophied, and free of microtrichia and setulae in others. Cercus of 1 of 4 types: free and elongate; fused with tergite 10, but free from each other and with tergite 10 forming a bridge between the cerci (e. g., Figure 20 View FIGURES 20–25 ); fused with tergite 10 but free from eachother, tergite 10 separated into right and left portions (e. g., Figure 34 View FIGURES 32–37 ); or fused with each other and tergite 10 (e. g., Figures 71 View FIGURES 70–72 , 77 View FIGURES 77–81 , and 85). Cercus in the first condition with scattered elongate setulae; those in the second and third condition with recurved stout setae; those in the fourth condition usually with stout modified setae (e. g., Figures 71 View FIGURES 70–72 and 77 View FIGURES 77–81 ). Reproductive system with large anteroventral pouch arising from vagina posteroventral to ventral receptacle and spermathecae. Ventral receptacle variously shaped, generally relatively short with a broad membranous duct, well-sclerotized “neck” and more lightly sclerotized “head” ( Figure 50 View FIGURES 46–50 ). Spermathecal ducts separate, elongate, with fine spiral ridges on entire length, constricted slightly just before spermatheca. Spermatheca highly variable in shape and surface texture, in New World species varying from elongate and tubular ( Figure 113 View FIGURES 110–114 ) to squat and pill-shaped (in C. murinum species complex, not illustrated), nearly smooth ( Figure 120 View FIGURES 115–121 ) to rugose and/or tuberculate ( Figure 137 View FIGURES 131–137 ).

Comments. Subepandrial sclerite examination requires separation of the epandrium and hypandrium. Given the destructive nature of this procedure, the subepandrial sclerite was not examined in species other than C. helvum and for that reason was not used for species differentiation or phylogenetic analysis. A subepandrial sclerite similar to that of C. helvum is visible posteriorly without epandrium-hypandrium disarticulation in C. floridense . This sclerite is not visible in any Neotropical species considered, likely because of the more congested nature of their hypopygia in posterior view.