Paraphaniosoma sexvittatum ( Lamb, 1914 ) 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 : 415-419

Paraphaniosoma sexvittatum ( Lamb, 1914) , comb. n.

Figs 58 , 59

Aphaniosoma sexvittata: Lamb 1914: 356 .

The original description of P. sexvittatum , although accurate, lacks detail and would not satisfactorily differentiate this species from other undescribed species I have seen from the East Palaearctic and Oriental regions ( Papua New Guinea, Malaysia, Taiwan). Therefore, a more detailed redescription is provided with figures of the male and female postabdomen.

The detailed description of the characters given by Lamb (1914), and the characters given in the key to genera provided in this article, serve to identify this species with relative ease. Additional characters and illustrations are given below, based on more material of this species from Aldabra ( Seychelles).

Redescription:

Male.

Head: Yellow, oc triangle yellow, but ocelli ringed with black; ocp brown except for broad postocular margin; fr narrow, at level of anterior oc about 0.4 width of head and at level of antennae about 0.6 width of that at level of anterior oc; eye elongate oval, lying oblique. Chaetotaxy: 2 reclinate orb with 3 short pale setulae in front, 1 vti and 1 vte, minute pvt (absent in some specimens); ocellars long and divergent with pair of short setulae behind these in between posterior ocelli; 14 setulae scattered on fr, but 6 of these in front of oc triangle about as long and strong as anterior orb; postoculars in one row; gena pale yellow and very pale yellow setulose with stronger setulae on oral margin, gena at middle about 0.5 highest diameter of eye; mouthparts yellow, palpus narrow; face mostly membranous with a very thin and shallow facial carina; antenna yellow, second segment paler with very thin short and pale dorsal seta; arista all brown, bare.

Thorax: Yellow, paler on pleura, scutum with 6 longitudinal dark brown stripes all separated from each other and from a brown patch at anterior end of scutum; middle stripes run from just anterior to transverse suture to scut, lateral to these and from behind transverse suture, a stripe runs between dc and ia lines of setulae on each side and another between sa and ia rows; a brown tiangular spot lies medial to pprn and confluent or narrowly separated from anterior dark scutal patch; anepisternum with brown streak at its lower margin and anepimeron with brown streak at its anterior margin, mtn brown, scut mostly yellow except for broad pale brown patch on disc and dark brown spot on sides at base. Chaetotaxy: 2 pprn, 2 ntpl, 1 posthu, 1 short ihu, 1 pra, 0+2 dc (anterior one short), 1 short sa, 1 long pa and 1 long post ia, scutal setulae in 4–6 irregular rows between dc lines, with stronger prscut pair, scut with basal and subapical pair, 1 anepisternal at upper hind margin and 1 katepisternal at upper hind corner.

Wing: Hyaline with pale brown veins; R 2+3 somewhat undulating at middle, R 4+5 and M 1+2 parallel and on costal margin separated by a distance equal to half distance between R 4+5 and M 1+2; crossveins and vein between discal and basal cell translucent pale yellow, distance between crossveins equal to 1.2× length of posterior crossvein. Haltere yellow with paler knob.

Legs: Yellow and pale brown setulose, hind trochanter normal, claws and pulvilli normal, mid tibia with strong ventral seta at apex. I cannot make out any row of short spines on the top of the front femora as described by Lamb (1914).

Abdomen: tg dark brown, dull with brown dusting, tg 5 with dorsal elongated quadrate brown spots, otherwise yellow; setulae brown to black about half length of tg.

Postabdomen: tg 6 narrow and brown, cerc very small, narrow and pale, pregenital st broad with deep excavation fringed with dense long pale setulae, surs visible in this space as 2 short black sinuous projections.

Female.

As male, but tg 6–8 each with 2 brown almost triangular spots narrowly separated at middle. Postabdomen: tg 7 complete and st 7 thinly sclerotized; tg 8 in two small lateral sclerites; st 8 larger than tg 8 and microtrichose; hypr distinct, trapezoidal and of similar size to small cerc, both structures with fine setulae.

Length: ơ and ^body 1.5 mm, wing 1.5 mm.

Type material examined: SEYCHELLES: ơ (holotype) “Mahé 08-9, Seychelles Exp. / Prof. J.S. Gardiner 1914-537 / A. sexvittata Lamb [handwritten] / Type H.T.” [on a red bordered label] ( BMNH); 3^(paratypes)

same data (1^BMNH, 2^CUMZ). Note: The holotype is in a reasonable condition: the pin damages only a part of the right half of the thorax. It has “spec 120” written on the mount .

Other material examined: MAURITIUS: 1ơ Wolmar, 1–2 km S, coast roadside, 1.vi.2000, J.W. Ismay (OXUM). SEYCHELLES: 1^Aldabra, West I., at light, nr settlement, 30–31.i.1968, B. Cogan &A. Hutson (NHML); 3ơ 3^Aldabra, West I., at light, nr settlement, 21–31.iii.1968, B. Cogan & A. Hutson (NHML); 1^Seychelles, North I., Calophyllum (Clusiaceae) woodland, 30.vii.2000, Malaise trap, J. Gerlach (NMWC). Distribution: Mauritius, Seychelles.

Genus Tethysimyia gen. n.

Type species: Aphaniosoma deemingi Ebejer, 1996 , here designated.

Etymology: From the Greek name Tethys (the sea goddess in mythology) and myia (fly), denoting the affinity of this genus with seashore habitats.

Diagnosis: Very small pale flies with rather large round head or head higher than long, very broad gena, well-developed, but narrow facial carina not reaching buccal margin, thus lower part of face between anterior eye margins flat, more or less square and carina therefore less conspicuous than in Krifomyia ; recessed antenna, but not in deep fossa; chaetotaxy generally reduced and fine, 2 very short orb set high on fr, 1 dc, scutal setulae in 4–10 rows between dc lines, absent pra and sa setae, but post ia, pa and katepisternal present even though short; R 4+5 and M 1+2 slightly convergent; male postabdomen exceptionally small with dorsally narrow, complete epandrium; female with poorly sclerotized s, pigmented or unpigmented.

Description:

Head: More or less round and rather large in proportion to thorax, fr broad and moderately convex and protruding in front of eye margin, eye round or only slightly oval, gena broad, at least half height of eye, finely setulose, ocp concave though not quite as much as in Aphaniosoma , face poorly sclerotized with distinct carina in upper half between antennae, antennae small with third segment rounded, arista 2-segmented, about twice as long as rest of antenna, thickened at base, but rapidly becoming thinner, mouthparts small, palp minute oval and finely setulose, labella not elongated, setulae along buccal margin, including those at vibrissal corner, short and fine. Chaetotaxy: 0–3 very short orb, 1 vti and 1 vte both short, pvt minute or absent.

Thorax: Rather rounded, not elongated, scut of normal shape. Chaetotaxy: 1 pprn, 1 posthu, ihu present or absent, 2 ntpl, 1 dc, scutal setulae very fine and pale in 4–8 rows between dc lines, pra and sa absent, 1 post ia, 1 pa, 1 anepisternal, 1 katepisternal, anepisternal and katepisternal setulae scanty and extremely fine or minute, scut with usual 4 marginals.

Wing: Hyaline, relatively short and broad, veins very pale yellow, hu break present, subcosta merges with R 1 before latter joins costa, no erect spinose setulae on dorsal aspect of costa, R 4+5 and M 1+2 slightly convergent towards apex. Haltere short, pale with pale knob.

Legs: Slender, femora not dilated, segments of all legs pale and finely setulose, mid tibia with apicoventral seta longer than diameter of tibia at apex, hind metatarsus sometimes dilated, hind trochanter normal.

Abdomen: More or less oval and slightly dorsoventrally compressed, 6 segments in male and 7 in female, tg with fine setulae, st poorly sclerotized.

Postabdomen:Atypical for Aphaniosominae and closer to that of Krifomyia , with reduced modification of hypopygial structures, which are simple and partially within small ep; ep distinct from tg 6 and surs fused to it, apparently formed of extension of inferior margin.

Distribution: Coasts and islands of the Gulf of Mexico, Red Sea ( Fig. 70 ), Indian and Pacific oceans.

Ecology: Probably associated with saline marshes and mangroves in coastal localities, in hot, tropical and subtropical climates.

Figures

Fig. 58. Paraphaniosoma sexvittatum (Lamb), ơ hypopygium, lateral (a) and ventral (b). Scale bar = 0.2 mm.

Fig. 59. Paraphaniosoma sexvittatum (Lamb): (a, b) ^postabdomen, lateral (a) and ventral (b), scale bar = 0.15 mm; (c–e) spermatheca, lateral (c), oblique (d), anterior (e), scale bar = 0.04 mm.

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