Aciuroides Hendel 1914

Kameneva, Elena P., 2012, Revision of Aciuroides Hendel and Neoacanthoneura Hendel (Diptera: Ulidiidae: Pterocallini), Zootaxa 3227, pp. 1-33 : 3-4

Aciuroides Hendel 1914

Aciuroides Hendel 1914

Type species. Aciuroides insecta Hendel 1914 (by original designation).

Hendel 1914 a: 172 (description); Hering 1941 b: 199 (new species); Aczél 1952: 419; Steyskal 1968: 54.1 (catalog); 1982: 141; Kameneva & Korneyev 2010: 896 (key to genera).

Idanophana Hering 1938 , new synonym

Type species. Idanophana gephyra Hering 1938 (by original designation).

Hering 1938: 193 (description); 1941 b: 198 (key to genera); Aczél 1952: 419; Steyskal 1968: 54.5 (catalog); 1982: 141 (key to genera).

Diagnosis. All species differ from other Pterocallini by the following combination of characters: head with anterior orbital seta long and situated at middle of distance between ocellar triangle and lunule; sides of frons without inclinate frontal setae anterior of the anterior orbital seta; arista short pubescent; ocellar seta and medial and lateral vertical setae long; mesonotum with 0 acrostichal, 2 dorsocentral, 0 presutural and 1 postsutural supraalar setae, and 2 pairs of scutellar setae; wing with vein R1 setulose over whole length, straight or slightly curved in both sexes, R2+3 slightly or strongly undulate, R4+5 bare; pterostigma in both sexes almost as wide as, and as long as costal cell, in males, not widened posteriorly; cell bcu closed with arcuate crossvein without posteroapical lobe; costal vein in males neither widened nor bearing denticle-like thickened setulae; abdomen shining, non-microtrichose, with all tergites and sternites well-developed, including tergite 6 of female which is short, but conspicuous; male without membranous pouches between tergites; male sternites 4 and 5 very wide and large ( Fig. 19 ); male terminalia displaced from ventral surface of abdomen apically, with long and narrow finger-like surstyli bearing 2 prensisetae and flat and narrow ventral lobes distal of prensisetae ( Fig. 21 ), sperm pump (ejaculator) and ejaculatory apodeme extremely large, almost as long as width of abdomen ( Figs. 20, 24 ); phallus 7–8 times as long as epandrium with surstyli ( Fig. 20 ), coiled at rest on right side of abdomen; female oviscape large and wide, usually longer than 3 posteriormost abdominal tergites; eversible membrane with short taeniae and blunt rounded scales in proximal portion of membrane; distal portion of membrane uniformly covered with broad and short scales with smooth margin; aculeus long, wide and flat, rigid, with cercal unit flattened, apically slightly narrowed, with short setulae ( Figs. 17 , 25 ).

Aciuroides is similar to Pterocerina Hendel , Coscinum Hendel , Apterocerina Hendel , Micropterocerus Hendel , and Neoacanthoneura Hendel in having the male pterostigma moderately narrow and non-expanded posteriorly, cell bcu without a posteroapical lobe, and the male abdomen is without membranous pouches between the tergites. It further differs from members of most of those genera, except Neoacanthoneura , in that the prescutellar acrostichal seta is lacking. Aciuroides resembles Neoacanthonevra in lacking the acrostichal seta and having a short pubescent or bare arista, but differs by the wide abdominal sternites, long finger-like surstyli, an extremely long sperm pump with large ejaculatory apodeme and the wide flattened aculeus of females.

Description. Head in lateral view higher and wider than long (in male and female); compound eye large, more than 4–6 times as high as gena; frons gradually curved anteriorly, forming blunt fronto-facial angle; face very faintly convex or nearly flat, vertical or slightly receding, antennal grooves not expressed; clypeus low, slightly convex; antenna moderately long and wide, flagellomere 1 not reaching ventral margin of face; arista conspicuously short pubescent; palpus elongate triangular, widest at middle and slightly curved dorsally, often flattened. 1 medial vertical, 1 lateral vertical, 1 pair vary long almost proclinate ocellar and moderately long divergent postocellar setae; 2 long reclinate orbital setae of various length; no inclinate frontal setae. Genal, postocellar and postvertical setae moderately or well developed, peristomal setulae mostly proclinate, no vibrissa-like setae among them. Head setae and setulae black.

Thorax longer than wide, sparsely and uniformly whitish microtrichose; 1 postpronotal seta; proepisternal seta very short, hair-like; 1 intra-alar, 1 postalar, 1 supra-alar and 2 dorsocentral setae, all postsutural; prescutellar acrostichal setae absent; 2 pair of scutellar setae; proepisternal seta; 2 anepisternal and 1 katepisternal seta; no anepimeral setae or setulae; subscutellum subshining. Thoracic setae and setulae black.

Legs unmodified, with coxae, femora and tibiae uniformly yellow to brown; fore femur with 2 posterodorsal and 1 posteroventral row of setae; midtibial spur nearly twice as long as width of tibia; hind femur with 2 dorsal preapical setae nearly as long as width of femur; tarsal setulae black.

Wing moderately wide, elongate, 4.0– 5.5 mm long, with sexually dimorphic, brown pattern with various spots or triangular incisions, or sometimes hyaline with 4 brown crossbands, or entirely yellow with paler areas. Costal vein evenly arcuate, with thin, non-modified setulae and 3 more or less conspicuous costagial, posthumeral and subcostal constrictions (breaks). Vein R1 setulose dorsally over entire length; vein R2+3 conspicuously undulate; vein R4+5 bare. Pterostigma moderately long and narrow, slightly shorter than costal cell and non-expanded posteriorly in both sexes. Crossveins r-m and dm-cu widely separated. Cell bcu closed with arcuate, basally receding vein CuA2, without posteroapical lobe; vein A1+CuA2 reaching (or almost reaching) posterior margin of wing; anal lobe and alula moderately narrow, vein A2 developed as fold.

Abdomen shining, non-microtrichose; all tergites and sternites well-developed, tergites 3–5 subequal in length in both sexes, female tergite 6 short, but conspicuous; male sternites 4–5 extremely wide and long, displacing genitalia to apex of abdomen.

Male terminalia: pregenital segments as in other ulidiids, sternite 6 bare, sternite 8 setulose; epandrium rounded, setose; surstylus finger-like, long and narrow bearing 2 prensisetae and a flat narrow ventral lobe, located distally of prensisetae; sperm pump (with its apodeme) extremely large, as long as width of sternite 5, the spermsac portion as long as its fan-like apodeme; phallus simple, coiled in rest in membranous pouch at right side of sternite 5, short microtrichose, without separated glans.

Female terminalia: oviscape longer than half length of preabdomen, wide; eversible membrane with short taeniae (at most as long as width of membrane), in middle portion evenly covered with rounded monodentate scales, except distal 0.2 of length covered with very short multidentate scales. Aculeus long, wide and flat, with flattened cercal unit, bearing short, mostly ventrally directed setulae. Spermathecae (2+1) spherical, with narrow necks. Vagina with simple, wide tubular (non-morula-like) ventral receptacle.

Character of larval feeding unknown.

Distribution. Almost all specimens are known from southern Brazil and adjacent parts of Paraguay and northern Argentina, except one specimen of A. gephyra Hering collected in Costa Rica.

Phylogenetic relationships. Aciuroides belongs to a group of genera in Pterocallini whose members share the following synapomorphies: anterior orbital seta at middle of frons (on posterior 0.3 of frons length in other Ulidiidae ), cell cup is closed with arcuate vein CuA2 forming no triangular lobe along vein A1 and aculeus highly modified, long, flattened and rigid, with flat cercal unit (Kameneva, in prep.). The group includes the genus Pterocerina and related nominal genera Tetrapleura Schiner , Apterocerina Hendel , Coscinum Hendel , Cyrtomostoma Hendel , Elapata Hendel , Lathrostigma Enderlein , and Micropterocerus many of which were established based on males of sexually dimorphic species and possibly are synonyms of either Tetrapleura or Pterocerina , as is to be shown in the revision of that group in progress (Kameneva, in prep.). Aciuroides is either a sister-group of these, or a derived lineage. At the same time, Aciuroides differs by the very short pubescent arista and bare vein R4+5, which could be either a primary condition or a secondary loss of synapomorphies of the Pterocerina group. The lack of prescutellar acrostichal setae, which could be autapomorphic, also occurs in Neoacanthoneura , but the latter differs in some other key characters and apparently cannot be a sister-group of Aciuroides .

Etymology and grammatical gender. The name of this genus is an attributive derived from the genus name “ Aciura ” in the family Tephritidae (composed of the Greek “axys”, pointed, and “uron”, tail) and a suffix “-oides” (having the appearance of), referring to the similarity in wing pattern to Aciura Robineau-Desvoidy (especially A. insecta ). It is to be treated as feminine in gender according to the Article 30.1.4.4 of the Code (ICZN 1999), as Hendel (1914 a) originally used it as feminine in combination with the epithet “ insecta ”, which in this case is an attributive in feminine gender.

Figures

FIGURES 19 – 26. Aciuroides insecta (Brazil: Nova Teutonia (BMNH), 3 (19 – 24) and Ƥ (25 – 26): 19, sternites 3 – 5 and terminalia, ventrally; 20, terminalia, detached, ventrally; 21, sternite 8 and epandrium, posteriorly; 22, epandrium, laterally; 23, apex of phallus; 24, ejaculator; 25, aculeus; 26, spermathecae. Abbreviations: ceu—cercal unit, eja—ejaculatory apodeme, epepandrium, ls—lateral surstylus, pr—prensisetae, spp—sperm pump, st 5 — sternite 5, st 8 — sternite 8.

FIGURES 16 – 18. Aciuroides gephyra, Ƥ (Brazil: Nova Teutonia (BMNH )): 16, female eversible membrane, ventrally; 17, aculeus, ventrally; 18, spermathecae. Abbreviations: ta—taenia.