Delia tibila, Ackland, 2008

Ackland, D. M., 2008, Revision of Afrotropical Delia Robineau-Desvoidy, 1830 (Diptera: Anthomyiidae), with descriptions of six new species, African Invertebrates 49 (1), pp. 1-75 : 50-53

publication ID	https://doi.org/ 10.5733/afin.049.0101
DOI	https://doi.org/10.5281/zenodo.7665433
persistent identifier	https://treatment.plazi.org/id/07587435-FF9E-FFD7-D15A-AA1C79ECFB00
treatment provided by	Felipe
scientific name	Delia tibila
status	sp. nov.

Treatment

Delia tibila View in CoL sp. n.

Figs 49 View Figs 44–49 , 78–83 View Figs 78–83

Etymology: The specific name tibila refers to the type locality ‘Tibila’ and is a noun in apposition.

Diagnosis:

♂ Genal setae biserial; arista long pubescent, total width of hairing half width of postpedicel; 3 pairs of presutural acr; scutellum with 8–12 hairs on disc; vein C with robust anterior spicules, 1.5 times as long as diameter of vein; mid tibia without av or ad setae; hind tibia with 3–4 av; sternite V with long posterior lateral setae. Genitalia: paraphalli long and undulating in lateral view.

Description:

Male.

Colour: Frontal stripe, parafrontals, parafacials, genae and face black in ground colour, with light to dark grey dusting, viewed from in front parafrontals, parafacials and interfrontalia matt sooty black, from a lower angle frontal stripe and face become light greyish white dusted, contrasting with rest of head; from above parafrontals and parafacials are light grey; parafacial at level of aristal base without shifting sheenstripe; occiput black with grey dust. Antennae entirely matt black. Palpi dark brown; prementum of proboscis dark brown, thinly dusted. Thorax black or dark brown in ground colour, with varying amounts of grey-brown dusting, pleura with shifting semishining patches; scutum with very indistinct brown vittae and grey shifting patches; viewed from behind median and lateral vittae are more distinct, lateral declivities grey dusted; scutellum as scutum, basal corners brown. Wing membrane brownish tinged, base of wing not significantly darker; veins brown; squamae creamy white, fringe white. Halteres pale yellow. Legs black, thinly dusted and slightly shining. Abdomen black in ground colour, viewed from above with shining black and dusted grey areas, from behind densely grey dusted with black median vitta (on tergite II slightly wider than hind tibia, on tergites III and IV becoming wider, on tergite V covering most of tergite except for grey dusted anterior lateral areas. Prehypopygial tergites black, thinly dusted, semi-shining; sternite V processes brown with reddish tinge.

Head: Eyes narrowly separated posteriorly (by diameter of anterior ocellus or slightly less), frontal stripe linear at narrowest part; parafacial at level of arista equal to width of postpedicel; peristomal margin not projecting, face slightly concave, distance between vibrissal setae more than distance between them and nearest eye margin. Gena below lowest point of eye margin 0.30–0.35× eye height; 6–7 pairs of frontal setae; 1 pair of fine interfrontal setulae on upper half of frons, closer to uppermost pair of frontal setae than to anterior ocellus; anterior genal setae biserial (4–5 upturned setae immediately posterior to subvibrissal setae); postpedicel twice as long as wide, not reaching peristomal margin (by 0.25× its width); arista long pubescent, longest hairs (on dorsal surface) twice length of basal aristal diameter, total width of hairing about half width of postpedicel.Proboscis with prementum slightly longer than palpi and as wide as postpedicel. Upper occipital setulae moderately long, with short row of setulae below row.

Thorax: 3 pairs of presutural acr, middle pair longer than others (2/3 length of 1st presutural dc), biserial, without hairs between rows; acr: dc ratio 10:6:10; 3 posthumeral setae, outer seta short and fine (about 1/3 length of posterior posthumeral and much thinner, with 4–5 associated hairs; notopleural depression bare apart from two strong setae; prealar very small or absent (represented by fine setula which is only slightly differentiated from scutal accessory hairs; scutellum with about 12 hairs on disc centrally and basally; anepisternite without developed upper anterior setula; 2 proepisternal setae, one is half length of other, without hairs; 1 proepimeral seta, with 5–6 associated hairs; katepisternals 1+2, lower posterior nearly as long as upper.

Wing: Vein C with anterior spinules robust, 1.5 times as long as diameter of C, stronger spines before distal break as long as small crossvein, or slightly longer; lower surface of C bare. Large crossvein straight, last section of M 1+2 1.8–1.9× length of preceding section. Lower squama not quite as large as upper. Wing length 5.5 mm.

Legs: Mid femur with 4 erect robust pv in proximal half (longest 1.5× depth of femur); hind femur with about 5 av in distal half, only 2–3 preapical, short blunt (? sometimes pointed) seta is present ventrally at extreme base of femur and only half as long as depth of femur; fore tibia with short pointed apical pv, 2 pv; mid tibia without av or ad, 1 pd, 1(2) pv, all very short, anterior surface of tibia with numerous semi-erect setulae and hairs which are as long as diameter of tibia; mid tarsomere 1 without lengthened dorsal setae or fringe; hind tibia with 3 av, 4 ad, 3 pd, 5–6 short pv on proximal 3/4. Pulvilli of fore legs as long as tarsomere 5.

Abdomen: About 2.7 times as long as greatest width (at basal margin of sternite III), dorsoventrally compressed. Tergites III–V with long hindmarginal setae (about as long as tergites), those on tergites II–IV separated from actual margin by width of hind tibia. Sternite III ( Fig. 80 View Figs 78–83 ) narrower than IV (1.5 times longer than wide); sternite IV ( Fig. 80 View Figs 78–83 ) wider than long (0.7 times longer than wide) with group of 7–8 long setae on each posterior corner, which reach to tip of processes of sternite V; sternite V processes ( Fig. 80 View Figs 78–83 ) shorter than base, with numerous lateral setae not longer than processes. Surstyli ( Fig. 78 View Figs 78–83 ) twice as long as length of cercal plate, in caudal view ( Fig. 78 View Figs 78–83 ) wider basally, then abruptly narrowing in distal third, in lateral view ( Fig. 79 View Figs 78–83 ) sinuate. Cercal plate ( Fig. 78 View Figs 78–83 ) 1.7–1.8 times longer than wide, rounded apically, bearing a few short setae which are not longer than cercal plate. Pregonite ( Fig. 81 View Figs 78–83 ) longer than wide, with 2 short distal setae; postgonite ( Fig. 81 View Figs 78–83 ) triangular with or without minute setula on ventro-apical corner. Aedeagus with distal section ( Figs 82, 83 View Figs 78–83 ) slightly more than twice as long as aedeagal apodeme, divided on distal half into pair of free paraphallic processes which are very slender and sinuate in lateral view, diverging in dorsal view. Acrophallus absent. Aedeagal apodeme 2.25 times as long as anterior width in dorsal view, in lateral view anterior margin downturned. Ejaculatory apodeme 0.3 times as long as aedeagal apodeme, widely expanded at one end.

Female.

Colour: Dark in ground colour with shifting brown and grey dusting; frontal stripe dark brown posteriorly, orange-brown on anterior half, viewed from in front at a low angle frontal triangle is light brownish grey dusted with dark brown velvety round patch between anterior ocellus and cruciate interfrontals, and similar patch surrounding ocellar tubercle; parafrontals brassy brown dusted when viewed from above, which becomes darker brown from in front; parafacials brassy dusted; gena with darker shifting brown patch behind vibrissal area; occiput grey to brownish dusted; prementum dark brown, thinly dusted, semi-shining in parts; palpi dark brown. Thorax dark in ground colour, with shifting brownish olive to grey dusting; scutum with traces of shifting vittae and semi-shining areas, viewed from behind darker medially, two wide lateral vittae which are very indistinct, lateral declivities lighter grey dusted; pleura with weakly shining brown patches, especially on anepisternum and katepisternum.Wing membrane weakly brownish tinged, hardly darker basally; squamae white with whitish fringe. Legs dark brown, weakly dusted and semi-shining.Abdomen dark in ground colour, viewed from above tergites with many shining patches especially medially and laterally, viewed from behind distinct shining black median vitta becomes visible, anterior margin of tergite II and posterior half of tergite IV darker, otherwise greenish grey dusted.

Head: Eyes separated by 1.4–1.5× their transverse width; frontal stripe at level of middle orbitals twice as wide as each parafrontal which widen anteriorly to slightly more than width of postpedicel; parafacial at narrowest part slightly less than width of postpedicel; gena below lowest point of eye margin 0.33× eye height; frontal setae differentiated into 3 pairs of exclinate orbitals, and 2 pairs of inclinate frontals (all in line); crossed interfrontals strong, placed just above middle of frontalia; 4–5 anterior genal setae immediately posterior to subvibrissal setae biserial and upwardly directed. Prementum and proboscis as in male. Upper occipital setae with scattered row of setulae below.

Thorax: 2–3 presutural setae, one pair longer than rest (half length of 1st presutural dc); notopleural depression bare apart from two strong setae. Prealar seta short and fine, but distinct (1/3 to 1/2 length of posterior npl); scutellum with only 2–4 short hairs on disc; anepisternite without developed upper anterior setula; 2 proepisternal setae, one long, one short; one strong proepimeral seta with 2–3 associated hairs; katepisternals 1+1 (posterior seta with short hair below it).

Wing: Vein C with anterior spinules strong and rather long, those on section between costal breaks about 2.5× costal diameter, pair of stronger spines before distal break nearly 1.5× length of small crossvein; large crossvein straight, last section of M 1+2 1.7–1.8× length of preceding section; lower squama smaller in area then upper. Wing length 4.7 mm.

Legs: Mid femur with a short av in proximal half, 2–3 short pv in proximal half; hind femur with 4–5 av in proximal half, which are not longer than greatest height of femur, only 2–3 short preapical pv; tibia with a strong ad (just below middle), a strong pv, more or less at same level (in one paratype on left leg only there is an extra pv towards apex); mid tibia without av, 1 long and strong ad, 1 pd, 2 pv; mid tibia with 2–3 av, 4 ad, 3 pd, without pv.

Abdomen: About 1.6 times as long as wide (at anterior margin of tergite III); tergites with rather short hindmarginal setae, most of them only half as long as tergites, including those on tergite V; postabdomen ( Fig. 49 View Figs 44–49 ) almost identical to D. bracata , perhaps cerci a little more slender.

Holotype: ♂ ETHIOPIA:‘Holotype’ [circular white label with red perimeter]; ‘ETHIOPIA / Tibila / 7.xi.1968 / Coll. R. Kano and T. Ohse’ [rectangular white printed label]; ‘HOLOTYPE ♂ / Delia tibila / D. M.Ackland’ [rectangular red printed label]. In good condition, abdomen dissected and mounted in glycerol in a plastic tube ( BMNH) .

Paratypes: 2 ♂ 1♀same data as holotype ( BMNH) .

Discussion: The absence of a sclerotized acrophallus combined with the shape of the surstyli (abruptly tapering in distal third in caudal view, with a tuft of hairs in inner margins) and longer setae on sternite IV, suggests that this species is correctly placed in the D. ventralis subsection.

Life history: Unknown.

Distribution: Only known at present from the type locality in Ethiopia.