Aphaniosoma acitergum, Ebejer, 2023

Ebejer, Martin J., 2023, The genus Aphaniosoma Becker, 1903 (Diptera: Chyromyidae) in the Eastern Mediterranean and Middle East, with descriptions of new species, European Journal of Taxonomy 872, pp. 1-161 : 15-19

Aphaniosoma acitergum sp. nov.

urn:lsid:zoobank.org:act:E2C92530-F430-47E2-A4D9-04D82300A4D3

Figs 1–3

Diagnosis

A yellow species with black longitudinal scutal vittae obscured by pale yellowish white microtomentum ( Fig. 2 ); 2 well-developed fronto-orbital setae. Male with the ventral margin of the 5 th tergite produced into an acutely pointed projection; a narrow yellow surstylus and similar pregonite almost parallel to each other lying along the large black basiphallus. In many respects, the new species is very similar to A. angulitergum sp. nov., but in that species the main modification of the tergites is in tergite 6, whereas in A. angulitergum sp. nov. it is in tergite 5. The pregenital sternites are also distinctly different in shape, e.g., compare sternite 6 in Fig. 3D with sternite 6 in Fig. 8C . The species is also somewhat similar to A. palestinense sp. nov. particularly in the male hypopygium. It differs from it in its paler colouration and in the shape of tergites 4–6, which are unmodified in A. palestinense , in the modification of the pregenital sternites (compare Fig. 3D with Fig. 70C ) and in details of the hypopygium, mainly in the shapes of the surstylus and gonites. Females of A. acitergum sp. nov. and A. angulitergum sp. nov. are difficult to separate from each other, but females of A. palestinense have a dark band across the frons.

Etymology

The species epithet is a combination of the Latin ‘ acies ’ (‘point’) and ‘ tergum ’ and refers to the acutely pointed postero-ventral angle of tergite 5.

Material examined

Holotype

ISRAEL • ♂; En Zin; 13 May 1999; I. Yarom and V. Kravchenko leg.; on Tamarix negevensis ; SMNHTAU 405818 .

Paratypes

ISRAEL • 1 ♀; same collection data as for holotype; SMNHTAU • 1 ♀; same collection data as for preceding; on T. parviflora ; SMNHTAU • 1 ♀; same collection data as for preceding; 9 Mar. 1999; SMNHTAU • 2 ♂♂, 2 ♀♀; ‘ Enot Zuqim ; 19 Mar. 1995; A. Freidberg leg.; SMNHTAU • 2 ♀♀; ‘ Iddan ; 20 Jun. 1995; I. Yarom leg.; SMNHTAU • 1 ♂; Rivivim ; 1 May 1995; I. Yarom leg.; on Tamarix sp. ; SMNHTAU • 4 ♂♂, 3 ♀♀; ‘ Enot Zuqim ; 3 Mar. 1998, on Tamarix sp. ; N. Meltzer and V. Kravchenko leg.; SMNHTAU • 1 ♂; ‘ En Mor ; 16 Mar. 1995; B. Merz leg.; MHNG • 5 ♂♂; Dead Sea , ‘ Enot Zuqim; 31°43ʹ N, 35°27ʹ E; alt. - 400 m; 25 Mar. 2000; M.J. Ebejer leg.; on Tamarix sp. ; MJE .

Description

MEASUREMENTS. Body length: male 1.2 mm, female 1.2 mm. Wing length: male 1.3 mm, female 1.3 mm.

Male (holotype)

HEAD. Yellow, ocellar triangle and occiput black but for a narrow postocular margin and small patch behind ocellar triangle; gena about half height of eye at middle and with scattered pale yellow setulae; a pair of vibrissal setae on each side; frons narrow at anterior margin about 0.5 × as wide as at level of anterior ocellus; ocellar setae about as long as anterior fronto-orbital, 2 well-developed fronto-orbital setae and 3 short setae anterior to these; about 6 setae on frons rather long and a distinctly longer pair in front of the anterior ocellus widely spaced and parallel; 1 inner and 1 outer vertical well-developed; paravertical setae short and convergent, postocular setae strong and in one row; face short, poorly sclerotized and depressed; median carina poorly developed; antenna yellow, pedicel paler than basal flagellomere and with distinct short seta dorsally; basal flagellomere with fine pubescence along anterior margin; basal ¼ of arista yellow contrasting with black distal ¾.

THORAX. Yellow; scutum with black longitudinal vittae separated by narrow yellow lines and covered with thin yellow microtomentum; scutellum yellow with black spot on lateral margin at base; pleura yellow with black triangular patch on katepisternum; meron and mediotergite black; chaetotaxy: 1 postpronotal, 1 presutural, 1 incurved intra-postpronotal, 2 notopleurals, 0+3 intra-alars, the posterior one quite strong, 1 postalar, 4+5 dorsocentrals, 2+5 acrostichals with no prescutellar setae, 4 scutellars, 1 anepisternal, 1 katepisternal at upper posterior corner.

WING. Veins all pale yellow; distance on costa between R 2+3 and R 4+5 about 0.5 × that between R 4+5 and M 1; distance between crossveins about 1.4 × as long as posterior crossvein, which is about 0.3 × as long as apical section of M 4. Haltere pale yellow.

LEGS. Fore femur with long setulae on posterior aspect; numerous pale yellow setulae scattered on all legs; apico-ventral seta on mid tibia present; claws black and pulvilli normal; tarsi yellow; hind trochanter not modified.

ABDOMEN ( Fig. 1A ). Basal tergites brown dorsally, becoming paler laterally; tergites 4–6 mostly yellow; tergite 5 ( Fig. 3C ) with acutely pointed projection at postero-ventral margin; tergite 6 ( Fig. 3B ), from ventral margin bearing a long narrow medially directed process that ends in a rectangular black margined lobe; tergites with fine pale setulae; sternites 5 and 6 modified ( Fig. 3D ).

HYPOPYGIUM ( Figs 1B , 3A ). Epandrium small and brown dorsally, bearing a narrow surstylus, setulose at tip; pregonite similar and visible externally without dissection in most specimens; aedeagus black with basiphallus /epiphallus shining black; cercus fused with the opposite side, pale yellow and with a pair of long subapical setae.

Female

As in male, but without secondary sexual characters; abdomen tending to be darker on posterior tergites.

Variation

The amount of darkening on pleura and the extent of pallor laterally on the tergites are variable in both sexes but more so in the female.

Figures

Fig. 1. Aphaniosoma acitergum sp. nov., ♂, holotype (SMNHTAU 405818). A. Habitus, lateral view. B. Hypopygium in situ, lateral view.

Fig. 2. Aphaniosoma acitergum sp. nov. ♂, paratype (SMNHTAU), thorax, dorsal view.

Fig. 3. Aphaniosoma acitergum sp. nov., ♂, paratype (SMNHTAU). A. Hypopygium, lateral view. B. Tergite 6, postero-ventral view. C. Tergite 5, lateral view. D. Pregenital sternites, top, lateral view, bottom, ventral view. Abbreviations: See Material and methods. Scale bars = 0.15 mm.

Fig. 8. Aphaniosoma angulitergum sp. nov., ♂, paratype (MJE). A. Hypopygium in situ, extended in alcohol, lateral view. B–C. ♂, paratype (SMNHTAU). B. Hypopygium, lateral view. C. Sternite 6, ventral view. Abbreviations: See Material and methods. Scale bar: B–C = 0.15 mm.

Fig. 70. Aphaniosoma palestinense sp. nov.A. ♀, paratype (MJE) head and thorax, dorsal view. B–E. ♂, paratype (SMNHTAU). B. Hypopygium in situ, postero-ventral view. C. Pregenital sternites, ventral view. D. Hypopygium, lateral view. E. Surstylus enlarged, postero-ventral view. Abbreviations: See Material and methods.