Elachiptera arabica Deeming, 2020

Dawah, Hassan A., Abdullah, Mohammed A. & Deeming, John C., 2020, An overview of the Chloropidae (Diptera) of Saudi Arabia, Zootaxa 4791 (1), pp. 1-71 : 17

Elachiptera arabica Deeming sp. n. male

( Fig 13 )

Holotype 1♂, SAUDI ARABIA: Abha , Hey Al-Nusub, 5–26.iii.2014, Malaise trap, H.A. Dawah (in National Mu- seum of Wales, Cardiff).

Colour. A black species, yellow on entire antenna with exception of arista, on head with exception of the ocellar prominence and the central infuscation of the upper half of the occiput, the dark marking of upper occiput extending obscurely to hind eye margin, and the extreme tip of the short proboscis black. Thorax black with prosternum, postpronotal lobe, scutellum and haltere yellow and either dorsocentral line with a yellow vitta that is widest at suture, a similar broader supraalar band of yellow running into the postalar callus, a quadrate dirty yellow marking immediately behind the postpronotal lobe, and one third of its size, the legs including coxae yellow with black claws. Wing hyaline with light brown veins, but these pale yellow basad of the basal cells, the squama pale with yellow border. Larger setae of head, mesonotum and scutellum appearing dark, but all clothing hairs of thorax and abdomen white, of the legs both pale and dark.

Head deeper than long and wider than deep (these at ratio of 27:20:38); frons slightly narrower anteriorly with frontal triangle extending to within an ocellus width of anterior margin, its sides slightly convex, shiny anterior to ocellar tubercle and also on a bare oval patch connected on either side to posterior ocelli, elsewhere covered in long pruinosity; all head setae weak, especially the vibrissa and genal setae; ocellar and postocellar setae long and cruciate, the former slightly proclinate and the latter erect; outer seta long, the inner short respectively; orbits with two long erect setae, the hindermost in length equal to height of gena; height of gena equal to one quarter of height of eye.

Thorax with mesonotum rather flattened with 1 postpronotal, 2 notopleural, 1 dorsocentral and 1 postalar seta; scutellum flat, one third of length of mesonotum, bearing 2 apical widely separated tubercles of one third of its length, these bearing a seta of scutellar length, the lateral pair of tubercles minute and bearing a short weak seta; pleura bare with a narrow triangular field of conspicuous pruinosity on upper hind corner of anepisternum, this continued across upper anepimeron and onto meron; katepsternum with a group of weak hairs on its upper margin.

Wing longer than abdomen. Ratio of lengths of costal sectors 1-4 (being 1 base to mouth of R1, 2 to mouth of R2+3, 3 to mouth of R 4+5, 4 to mouth of M1+2) 46:38:28:14 and of section of M1+2 between crossveins: length of posterior crossvein: apical section of M3+4: basal section of M3+4 = 13:8:25:52.

Legs not unusual in any way, the mid femur with a stridulatory area dorsally; mid tibia with an apicoventral spur that is as long as the tibia is thick; the hind tibial organ present, occupying slightly less than one third of tibial length and situated slightly more basally than apically, pruinescent, appearing either pale grey or brown according to the incidence of light.

Abdomen with all segments discrete apart from the fused tergite 1+2, this weakly sclerotized medially; tergites conspicuously long setulose, especially laterally; sternites inconspicuous, desclerotized.

Length 2mm.

Affinities. This species closely resembles Elachiptera lenis Collin , described from Siwa Oasis, Egypt and recently identified by Dr. M.J. Ebejer from U.A.E. and also Elachiptera lerouxi (Séguy) , described from high altitude in Kenya and further recorded from “ Rhodesia ” and Uganda. E. lerouxi was redescribed by Sabrosky (1951: 789) in detail from a Ugandan female also collected at high altitude. Whereas in E. lenis and E. lerouxi the arista is flattened and lanceolate, in E. arabica it is filiform, though appearing to be thickened on account of its compact, short pubescence. Also E. arabica differs from the other two species in lacking the dorsal black marking on the outer side of the postpedicel basad of the insertion of the arista that is present in these two species, in having the scutellum and dorsocentral lines of the mesonotum yellow and in having the upper occiput much more extensively infuscate. Nartshuk (2010: 69) gave figures of variation in colour pattern of the dorsum of the thorax in three varieties of Elachiptera bimaculata (Loew) from Greece, which is another closely-related species. All these have the predominant ground colour yellow, all with black longitudinal vittae, the one with long median vittae on the anterior two thirds of length and lateral vittae long, occupying over half mesonotal length; the second similar with the median vittae very short, extending only to anterior level of lateral vittae; and the third lacking median vittae and with the lateral pair more oval and only present on posterior half of mesonotal length. This precludes E. arabica from inclusion in that variable species.

Etymology. The specific name indicates the region from which the species is described.

Figures

FIGURE 13. Elachiptera arabica Deeming sp.n. Male.