Aristobatina rufithorax (Enderlein)

Marshall, Stephen A., 2014, A review of the Afrotropical genus Aristobatina Verbeke (Diptera: Micropezidae: Taeniapterinae), with descriptions of four new species from the Eastern Arc Mountains of Tanzania, African Invertebrates 55 (1), pp. 143-143 : 150-153

Aristobatina rufithorax (Enderlein)

Figs 12–14, 17 , 18–20

Tanypoda rufithorax: Enderlein 1922: 198 .

Aristobata rufithorax: Hennig 1935: 68 .

Aristobatina rufithorax: Verbeke 1951: 59 ; Steyskal 1980: 579.

Redescription:

Length (head to wing tip): 14–16 mm.

Colour: Head orange, except for black palpus and swollen part of frontal vitta; notum and upper pleuron brick­red; foreleg black, except tarsus; tarsomeres 1–3 white, distal tarsomeres dark; mid femur black with orange apex, mid femur orange at base and apex; abdomen black, except for extreme base and white fasciae across pleuron on segments 2 and 3 ( Fig. 18 ).

Head: Pedicel and scape with uniformly short setae only; frontal vitta dull, weakly differentiated from orbits, virtually parallel-sided throughout, slightly raised in front of ocelli, slightly depressed behind ocelli and on anterior ⅔; 2 pairs of fronto­orbital setae, 1 anterior to level of ocelli, 1 slightly posterior; postocellar and inner vertical setae well­developed, outer vertical setae absent.

Thorax: Cervical sclerite convex and dull, with small anterolateral vertical carina; proepisternum with ca 7 long, marginal ventral setae over entire length; katepisternum with double row of thin black setae, anterior row ½ as high as posterior row, mixed with additional long thin setulae, forming an extensive third row; scutellum with 1 pair of marginal setae and 2 small marginal setulae; 1 small setula between postalar and dorsocentral setae; fore tarsus 1.3× length of remaining tarsomeres combined.

Wing: CuA 2 meets anal vein at a distinct angle (about 50°) and almost at the same level as bm­cu; wing membrane lightly and evenly infuscated on distal ⅔, clear in basal ⅓; tegula and basicosta slightly darker than adjacent wing base.

Female abdomen: Oviscape black, pruinose, except at apex; spermathecae elongate, twice as long as wide, slightly swollen apically, with transverse striations, base very elongate and sinuate, especially in distal ⅓; with very prominent lateral processes ( Fig. 17 ).

Male abdomen: Pleuron with large, dome­like differentiated area (pleural sac) covering entire ventral ½ of pleuron 4 ( Fig. 20 ); hypandrium with elongate anterior plate and strong posterodorsal arms connected to phallic plate; basiphallus and left postgonite elongate, extending far beyond base of distiphallus; right postgonite unmodified ( Fig. 13 ); distiphallus with tubular basal part bifurcating before transition into strongly recurved membranous distal part, apex with a finely spinulose glans ( Fig. 14 ); ejaculatory apodeme enormous, several times as large as epandrium ( Fig. 13 ); genital fork (sternite 5) with V-shaped gap at base, inner surfaces of arms densely spinose ( Fig. 12 ).

Type material: Barraclough (1996) examined the types in ZMHB and designated a lectotype female from Tanzania. Although the type material is in very poor condition, the species described above fits the original description and Barraclough’s notes on the types.

Additional material examined: 1♀ TANZANIA: Morogoro Region, Udzungwa Mts Nat. Park , 07°50'35''S 36°49'49''E, 11–13.xi.2009, 1000 m, T. Pape & S. A . Marshall ( ZMUC, DEBU); Uluguru Mountains : “Tanganyika, Ulguru Mts near Morogoro, 700 m, i.1962 ” ( CNCI) .

Comments: The large differentiated areas on pleuron 4 of the male look much like the differentiated, apparently thin­walled and inflatable areas (“pleural sacs”) often found on pleuron 2 or 2–3 of many other male Taeniapterinae. These structures do not occur on pleuron 4 in other genera of micropezids. Clearly homologous, although less conspicuous, swollen areas are found on pleuron 4 of A. morogoro sp. n. and A. metamelasma sp. n.

Figures

Figs 12–17. Aristobatina spp.: (12–14) A. rufithorax male: (12) sternite 5; (13) terminalia; (14) apical part of distiphallus; (15–17) spermathecae and associated ducts: (15) A. morogoro sp. n., single small spermatheca and one of the paired large spermathecae; (16) A. melasma sp. n., spermatheca, one of pair; (17) A. rufithorax, bursa copulatrix, spermathecae and spermathecal ducts. Not to scale.

Figs 18–26. Aristobatina spp.: (18–20) A. rufithorax: (18) female; (19) female head; (20) male; (21–23) A. melasma sp.n., holotype male: (21, 23) ovipositing; (22) head; (24–26) A. morogoro sp. n.: (24) female; (25) female head; (26) male.