Aphaniosoma cristatum, 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 : 41-44

Aphaniosoma cristatum sp. nov.

urn:lsid:zoobank.org:act:AF2ED06E-2846-4E11-84BD-036B38ACA722

Figs 17–18

Diagnosis

A yellow species of the collini group, with brown longitudinal scutal vittae and strong presutural, prealar and dorsocentral setae. Male with a flattened crest on the hind trochanter and a small tubercle at the extreme base of the hind femur ( Fig. 17B ). Among others of the collini group with pale tarsi and a presutural intra-alar seta, the new species is most similar to A. hackmani Lyneborg, 1973 ; males are easily separated on the basis of different hind trochanter modifications, but it is likely that the unknown females of A. cristatum are more difficult to differentiate.

Etymology

The species epithet is derived from the Latin ‘ crista’ meaning ‘crest’ and refers to shape of the modified hind trochanter in the male.

Material examined

Holotype

ISRAEL • ♂; Dead Sea , ‘ Enot Zuqim; 31°43ʹ N, 35°27ʹ E; alt. - 400 m; 25 Mar. 2000; M.J. Ebejer leg.; on Tamarix sp. ; OUMNH DIPT0800-01 .

Paratype

ISRAEL • 1 ♂; same collection data as for holotype; OUMNH DIPT0800-02 .

Description

MEASUREMENTS. Body length: male 1.9 mm. Wing length 1.9 mm.

Male (holotype)

HEAD. Slightly higher than long and entirely yellow except for the black-ringed ocelli; frons narrowed anteriorly: at level of antennae about 0.7 × as wide as at level of anterior ocellus; gena narrow in front, much deeper behind, about 0.7 × as high as eye below middle of eye, with numerous pale setulae; occiput in profile narrowly visible behind eye; long postocular setulae in one row; 2 long pale vibrissal setulae; face short, poorly sclerotized and depressed; median carina visible to clypeus; antenna yellow, pedicel paler than basal flagellomere and with distinct dark seta dorsally; basal flagellomere with fine and dense pubescence along anterior margin, shorter than diameter of first segment of arista; arista dark on apical ¾ and finely pilose; chaetotaxy: 2 strong fronto-orbitals with three very short setulae interior to them, paraverticals short and convergent; 1 inner and 1 outer vertical, both strong; ocellars as long as anterior fronto-orbital; about 20 pale setulae across frons all more or less of uniform size.

THORAX. Yellow; scutum covered with dense pale microtomentum, with broad brown longitudinal vittae leaving only narrow yellow lines between them; scutellum yellow; mediotergite dark brown; pleura yellow with light brown mark on middle of anepisternum and katepisternum, meron with black mark; chaetotaxy: 1 postpronotal with weaker seta adjacent, 1 incurved intra-postpronotal, 1 long presutural, 2 notopleurals, 1+3 intra-alar, 1 postalar, 2+4 dorsocentrals, 1+4 acrostichals with prescutellars, 4 scutellars, 1 anepisternal with 2 shorter and thinner setae below, 1 katepisternal at upper posterior corner with 6 short thin setae down middle.

WING. Veins yellowish brown; 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 1.6 × as long as posterior crossvein, which is about 0.4 × as long as apical section of vein M 4 and lies oblique, forming an angle of about 60° with M 4. Haltere pale yellow.

LEGS. Fore femur with long setulae on posterior aspect; numerous pale setulae scattered on all legs; apico-ventral seta on mid tibia present; claws black and pulvilli normal; tarsomeres of all legs yellow; hind trochanter modified with narrow crescent shaped process, pilose over most of its crest; hind femur at extreme base of ventral surface with a distinct small tubercle.

ABDOMEN ( Fig. 17 ). Tergites brown dorsally over basal half; tergite 5 longer laterally than at middle and about 2.5 × as long as tergite 4; tergite 6 very short and small in comparison and mostly hidden by tergite 5 ( Fig. 18C ); setulae on tergites numerous, short and pale brown; sternite 6 transverse oval with a short ventral setulose lobe on each side ( Fig. 18B ).

HYPOPYGIUM ( Fig. 18C ). Yellow; epandrium narrow, bearing long pale surstylus curved into almost a semicircle in distal half and ending in three black and broad, flattened spines ( Fig. 18D ); hypandrium with narrow lateral arms ending caudally at lower edge of epandrium; pregonite not visible if present; postgonites short, narrow and translucent, not visible in lateral view; epiphallus pale, with rounded apex and separate from apex of basiphallus; distiphallus pale, cylindrical and uncomplicated, weakly sclerotized; cercus pale yellow with shorter setae compared to those of congeners.

Female

Unknown.

Variation

Paratype a little paler than holotype.

Distribution

Israel.

Figures

Fig. 17. Aphaniosoma cristatum sp. nov. A. ♂, holotype (OUMNH DIPT0800-01), habitus, lateral view. B. ♂, paratype (OUMNH DIPT0800-02), hind trochanter and hypopygium in situ, ventro-lateral view.

Fig. 18. Aphaniosoma cristatum sp. nov., ♂, paratype (OUMNH). A. Hypopygium in situ, posteroventral view. B. Pregenital sternites, ventral view. C. Hypopygium, lateral view. D. Apex of surstylus, ventral view, enlarged. Abbreviations: See Material and methods.