Neoethilla, Cerretti, Pierfilippo, Wood, D. Monty & O'Hara, James E., 2012

Cerretti, Pierfilippo, Wood, D. Monty & O'Hara, James E., 2012, Neoethilla, a new genus for the first record of the Ethillini from the New World (Diptera, Tachinidae, Exoristinae), ZooKeys 242, pp. 25-41 : 26-31

Neoethilla gen. n. Figs 1 a–f, 2 a–b, 4 a–d, 5 a–e

Type species:

Exorista ignobilis van der Wulp, 1890, by present designation.

Etymology.

The compound name Neoethilla refers to the New (Latin, neo) World distribution and to the suspected close relationship of this genus with the Old World genus Ethilla Robineau-Desvoidy, 1863.

Description.

This generic description is based on a redescription of the single included species, Neoethilla ignobilis .

Length: 5.5-7.5 mm.

Colour: Head mainly black, covered with grey microtomentum. Palpus black to brown (usually paler in female). Thorax and legs entirely black. Abdomen mainly black but reddish yellow laterally (Fig. 1 a–b). Tegula and basicosta black.

Head (Figs 1 a–e, 2a): Large in dorsal view, about as wide as thorax; higher than long in lateral view. Compound eye densely covered with long ommatrichia (Fig. 1 c–f). Frons at its narrowest point 2/3-6/7 (♂♀) as wide as eye in dorsal view (no significant sexual dimorphism in examined specimens). Frontal vitta (= interfrontal area) clearly widening anteriorly. Outer (= lateral) vertical seta not differentiated from postocular setae in male, well developed in female. Ocellar seta absent (Figs 1 c–d, 2a) or very small; ocellar triangle with several short, proclinate setulae (Fig. 2a). Fronto-orbital plate of male with about three irregular rows of fine, medioclinate setae lateral to frontal setae. Seven to 10 frontal setae. Two or 3 upper (= dorsal) reclinate orbital setae, often not clearly differentiated from frontal setae. Proclinate orbital setae absent in male, 2 in female (Fig. 1 a–b). Parafacial covered with proclinate, short, fine setae (Fig. 1 a–b, 1 e–f). Facial ridge straight in profile, with only a few setae above vibrissa on about 1/5-1/4 of its length. Vibrissa arising at about level of lower facial margin. Face concave; lower facial margin not visible in profile. Antenna slightly shorter than facial ridge. Postpedicel 3.0-3.5 times as long as pedicel. Arista bare, thickened on basal 2/5-1/2. First aristomere not longer than wide (usually shorter); second aristomere 1-2 times as long as wide. Genal dilation well developed. Gena in profile very narrow, about 0.10-0.15 times as high as compound eye (height measured in the same vertical plane as height of head). Postocular setae fine, relatively long and slightly bent anteriorly. Occiput flat, with 1-2 rows of black setulae behind postocular row. Prementum not more than 2 times as long as wide; palpus well developed, apically covered with setulae, often strongly clavate in female.

Thorax (Figs 1 a–d, 2 b–d): Postpronotum with 4 setae; 3 strongest, basal, arranged in a line (Fig. 2b). Scutum with 2-3 posthumeral setae, 1 + 3 supra-alar (first postsutural supra-alar seta at most as long as a notopleural seta), 0-1 + 3 intra-alar, 3 + 4 dorsocentral, 3 + 3 acrostichal setae. General hair-like setulae of scutum fine, relatively long and erect. Prosternum laterally setose. Proepisternal depression bare. Two katepisternal setae (the posterior one larger). Katepimeron setulose along its length. Anepimeral seta at most half as long as posterior katepisternal seta. Scutellum wider than long, covered with long, fine, erect setulae. Three pairs of marginal scutellar setae (basal, subapical, apical) (Figs 1 c–d, 2c); basal and subapical setae about equal in size; apical pair shorter, crossed and sub-horizontal. Scutellum without discal setae. Anterior and posterior lappets of metathoracic spiracle unequal in size.

Legs: Preapical anterodorsal seta of fore tibia about as long and stout as preapical dorsal seta. Mid tibia with 1 anterodorsal seta. Hind tibia with a row of moderately spaced, comb-like anterodorsal setae (Fig. 2e); 2 dorsal preapical setae. Preapical posteroventral seta of hind tibia not differentiated. Claws about as long as fifth tarsal segment in male (Fig. 2f), considerably shorter in female.

Wing (Figs 1 a–d, 2d): Bend of vein M usually obtuse. Cell r4+5 open. Section of M between crossveins r-m and dm-cu longer than section between dm-cu and bend of M. Section of M between dm-cu and bend of M shorter than post-angular section of M. Vein R4+5 with a single setula at base dorsally and 0-1 ventrally. Lower calypter large and strongly convex, especially along its lateral and posterior margins (Fig. 2d).

Abdomen (Fig. 1 a–d): Syntergite 1+2 with mid-dorsal depression extending to hind margin. Tergites 1+2 and 3 with a pair of fine median marginal setae, sometimes not differentiated from the general abdominal setae, and a pair of lateral setae; tergite 4 with a row of marginal setae; tergite 5 with scattered weak setae. Tergites 3 and 4 without median or lateral discal setae.

Male terminalia (Figs 3 a–b, 4 a–d, 5 a–c): Sternite 5 with deep median cleft, outer lobe almost truncate along posterior margin (Fig. 3 a–b). Tergite 6 large, plate-like (not divided into two sclerites nor indentate on posterior edge), bare; tergite 6 separated from tergite 5 and segment 7+8 by membrane. Cerci (Figs. 4 a–b, 5 a–b) almost flat, wide in posterior view (sub-ovoid), not fused medially (i.e., longitudinal medial suture complete), distally very slightly divided (Figs 4b, 4d, 5b). Surstylus long, wide and sub-triangular in lateral view, distal tip sometimes slightly bent posteriorly (Figs 4c, 5a). Posterior half of lateral surface of surstylus with several stout setae. Pregonite and postgonite not fused. Pregonite strongly recurved and pointed. Processi longi long, slender and well separated from each other. Epiphallus stout, well sclerotized, attached to basal portion of basiphallus (Fig. 5c). Connection between basiphallus and distiphallus strongly sclerotized (Fig. 5c). Lateroventral sclerites of distiphallus well developed, strongly sclerotized with robust spines lateroventrally (Figs 4 a–b, 5c).

Female terminalia. Ovipositor short, not telescopic as in Winthemiini .

Egg. Plano-convex macrotype unembryonated; long-oval in dorsal view; anterodorsally operculate (Fig. 5 d–e). Dorsal, convex surface of egg characterized by a strong polygonal micro-sculpturing.

Remarks.

Neoethilla is superficially similar to Winthemia because it has an enlarged compound eye covered with thick and long ommatrichia and parafacial covered with fine setulae. Moreover, Neoethilla and Winthemia both have a short first postsutural supra-alar seta, a comb-like row of anterodorsal setae on hind tibia and a fully setulose katepimeron. Neoethilla is distinguishable from Winthemia (i) in having the three strongest basal setae of postpronotum arranged in a line, (ii) in lacking the lateral scutellar setae and (iii) in having processi longi of male terminalia long, slender and well separated from each other. Females of Neoethilla have a short ovipositor and a dorsally operculate plano-convex egg. These characters, together with the strongly convex lower calypter, suggest that Neoethilla has an ethilline affiliation. Within this tribe the new genus is characterized by the following combination of character states: (i) parafacial fully setulose, (ii) gena very narrow (0.10-0.15 times as high as compound eye), (iii) ocellar setae absent or very reduced, (iv) three strongest basal postpronotal setae arranged in a line, and (v) lateral scutellar setae missing.

Included species and examined specimens