Aphaniosoma ugabensis, Ebejer, 2009

Ebejer, Martin J., 2009, A revision of Afrotropical Chyromyidae (excluding Gymnochiromyia Hendel) (Diptera: Schizophora), with the recognition of two subfamilies and the description of new genera, African Invertebrates 50 (2), pp. 321-321 : 410-412

Aphaniosoma ugabensis sp. n.

Fig. 55

Etymology: The species name is derived from the type locality, Ugab River in Namibia. Diagnosis: Almost entirely yellow species with 2 pairs of long setulae on fr, only dark areas are small rectangular patch at anterior end of scutum just above occipital foramen and on metanotum. There are no external features to help in the identification of this species. Male postabdomen with long narrow pointed psg and short truncate prg; surs reduced to an inconspicuous lobe; pregential st with distinct midline ventral projection. Description:

Male

Head: Entirely yellow, only ocelli ringed with black, fr broad, converging anteriorly so that at level of antennae it is about 0.7 as wide as at level of anterior oc, face small, depressed (carinal area not visible), eye narrow, oval, lying oblique, gena yellow, shrivelled, probably about half height of eye and having numerous yellow setulae, setae at vibrissal corner not seen, mouthparts yellow, 4 setulae on fr with 2 pairs of longer setulae, one above lunule and one in front of oc triangle, 2 short orb and in front of these 2 very short fine setulae,1 vti and 1 vte, pvt distinct and convergent, oc long, divergent, antennal segment 3 yellow, arista dark brown on apical 2/3 of segment 2 of arista.

Thorax: Scutum and scut yellow with pale brown longitudinal stripes on posterior half of scutum and brown patch on extreme anterior scutum above neck, mtn dark brown, pleura yellow. Chaetotaxy: 1 pprn, 1 posthu, 1 ihu, 2 ntpl, 0+3 ia, 2+3 acrs, 3+4 dc only the posterior one well-developed, prpl not seen, 1 pa, 2 pairs of marginal scut, 1 katepisternal, 1 anepisternal, all setae pale, with shorter ones and setulae inconspicuous.

Wing: Hyaline and uniformly microtrichose, veins yellow, distance between R 2+3 to R 4+5 on costal margin about 0.5 that between R 4+5 and M 1+2, distance between crossveins about equal to length of posterior crossvein and length of apical section of Cu about 3× length of posterior crossvein. Haltere yellow.

Legs: Yellow and fine yellow setulose, tarsomere 5 of anterior leg brown.

Abdomen: Yellow on all tg.

Postabdomen: Yellow with no distinctive external features.

Female.

As male, but several specimens have the middle third of femora diffusely infuscated dorsally. (Postabdomen not dissected.)

Length: ơ and ^body 1.2 mm, wing 1.4 mm.

Holotype: ơ NAMIBIA: Omaruru District , Ugab R., 2 km W Brandberg Wes, 20°58'05"S: 14°06'36"E, 23.x.1998, sweeping, E. Marais (in glycerine, NMNW).

Paratypes: 2ơ 8^same data as holotypes (in alcohol, NMNW) .

Remarks. The holotype is not in good condition due to some shrivelling and broken setae.

Genus Krifomyia gen. n.

Type species: Rhicnoessa minutissima Bezzi, 1908: 200 , here designated.

Etymology: From Greek krifos (secret, secluded) and myia (fly), and refers to the genus being rare and unobtrusive.

Diagnosis: Well-developed, broad facial carina extending from lunule to just below antennae where it broadens laterally leaving antennae in deep pits; head short with rather inflated fr that has parallel margins and which, in profile, is visible all along eye margin from vertex to antenna, gena higher than height of eye which, in profile, is round to oval and small relative to head size, when compared to other genera; pvt present, ihu minute, posthu short, sa and katepisternal setae absent, veins R 4+5 and M 1+2 converging slightly towards apex, apicoventral seta on mid tibia present.

Description:

Head: Rectangular in profile and almost twice higher than long; fr broad and parallel-sided, protruding above and in front of eye margin when seen in profile; finely setulose; gena deep, at middle equal to or greater than height of eye and with wide post genal dilation; fine pale setulose, postgenal seta absent; face long with very broad carina extending from lunule to just below antennae, where it widens; thus, antennae lie in deep fossae, with segments 1 and 2 very short, segment 3 rounded except for shallow dorsal excavation near insertion of arista; arista with 3 segments and shorter than usual for the family; 2 short reclinate orb, 1 vti and 1 vte, both shorter than usual for this family, oc setae divergent, pvt minute and parallel, sometimes absent, few postocular setulae in one row; mouthparts all yellow, well-developed with long proboscis, geniculate labella and narrow elongated palp.

Thorax: A little shorter and broader than usual for the family. Chaetotaxy: 1 short pprn and 1 short posthu, a minute but distinctly incurved ihu, 2 ntpl, 1 pa, 1 short post ia, 1 dc, acrs very short and in more than 2 irregular rows, 1 anepisternal closer to upper margin; absent sa and katepisternal setae; scut with 1 pair basals and 1 pair subapicals, all about as long as dc.

Wing: Hyaline, veins very pale yellow, only Cu along discal vein a little darkened; RM stem vein thickened; anal cell pointed apically along anal vein; costal setulae all fine and pale; R 2+3 and R 4+5 very slightly divergent. Haltere yellow with creamy white knob. Legs: Entirely dull yellow with short pale setulae, only claws darkened; apicoventral seta of mid tibia present and longer than diameter of tibia at apex; legs without dilated segments or special modifications.

Abdomen: All tg normally sclerotized and with a few very fine setulae scattered thinly on all segments, but on tg 6, which is as long as tg 5, stronger and more numerous setulae present.

Postabdomen: Male hypopygium very small with reduced appendages, short ph apd and markedly simplified ph compared to the rest of the family. Female abdomen with 8 segments, sclerotized st 8; 2 unpigmented s.

Remarks. This genus belongs to the Aphaniosominae because of the following combination of characters: absent incurved lower orb, concave ocp, long apicoventral seta on mid tibia, anepisternal seta above middle of posterior margin, incurved ihu setula, absent hemispherical ep. With Paraphaniosoma it shares the post ia seta and more than two rows of scutal setulae between dc lines. However, it differs in the much simplified hypopygial structures, absent sa and katepisternal setae, markedly different shaped head, well-developed proboscis and in the wing having the costal vein with spinescent setulae and a thickened hu crossvein.

Distribution: Atlantic coast of southern Africa ( Namibia) ( Fig. 70 ).

Ecology: Krifomyia , known from a single species so far, is rare and by all accounts a rather cryptic inhabitant of hot dry coastal regions.

Figures

Fig. 55. Aphaniosoma ugabensis sp. n., ơ: (a) hypopygium, lateral; (b) st 6, ventral. Scale bar = 0.15 mm.

Fig. 70. Distribution of Krifomyia gen. n. (•), Paraphaniosoma gen. n. (x), and Tethysimyia gen. n. ().