Miombomyia brevicollis, Jaschhof, 2023

Jaschhof, Mathias, 2023, A new mycophagous gall midge, Miombomyia brevicollis gen. et sp. nov. (Diptera Cecidomyiidae: Micromyinae), from the Caprivi Strip of northeastern Namibia, Zootaxa 5336 (3), pp. 447-450 : 449-450

Miombomyia brevicollis sp. nov.

urn:lsid:zoobank.org:act:F3C930B8-85F1-4421-B67C-1011ECA7A502

Diagnosis. As the only species classified in Miombomyia , M. brevicollis is distinguished by the generic characters described above. Should other species of this genus be found in the future, one may assume that terminalia characters become defining.

Description. Male. Body length 1.2 mm. Head ( Fig. 1D ). Small, without setae, completely roofed by anterior portion of scutum. Ocelli absent. Compound eyes small, without dorsal bridge. Antenna shorter than body; scape slightly smaller than pedicel, both non-setose; 14 short-necked flagellomeres, increasingly more slender towards antennal apex except for ultimate flagellomere which is thicker than penultimate, nodes of all flagellomeres with dense cover of trichia and, subapically, several hair-shaped translucent sensilla of various sizes; first and second flagellomeres each with single large seta dorsally; fourth flagellomere vase-shaped, two times as long as broad ( Fig. 1A‒B ). Palpus diminutive, singlesegmented, with a few short hair-shaped translucent sensilla, no setae. Labella absent. Thorax ( Fig. 1D ). No apparent neck but small cervical sclerites present. Scutum with sparse setae laterally and dorsocentrally. Pronotum narrow, slightly sickle-shaped, with 2 lateral and 3 dorsal setae. All other sclerites, including scutellum, non-setose. Laterotergite unusually small. Legs ( Fig. 1C ). 1.5‒2.0 times as long as body, with short setae. Claws small, strong, slightly bent, toothless. Empodia vestigial. Wing ( Fig. 1E ). Longer than body, 2.4 times as long as broad, non-setose except for C which has setae all round. All veins but C poorly contoured, with some (Rs, M 4, m-cu, CuA) even weaker than others. No costal break. R 4+5 fading out apically. Abdomen. Sclerites poorly contoured, very sparsely setose. Terminalia ( Fig. 2A ). Ninth tergite short, rectangular, with irregular row of setae posteriorly. Gonocoxal synsclerite with deep, V-shaped emargination ventrally; area below the emargination membranous, with sclerotized edge basally; setae sparse, randomly distributed; dorsal apodemes narrow, almost as long as distance separating them. Gonostylus with posteromedial orientation, consisting of broad, flattened basal portion that transitions into a much narrower apical process with strong, comb-shaped tooth ( Fig. 2B ). Tegmen largely membranous, 1.5 times as long as broad, narrowed towards rounded apex; parameral apodemes small, moderately sclerotized. Aedeagal apodeme almost as long as gonocoxae, moderately sclerotized, apically broadened into weakly sclerotized cap. Membranous portion of aedeagus covered with small pointed warts. Cerci small, with large setae (not illustrated). Hypoproct not apparent.

Female and preimaginal stages. Unknown.

Etymology. The specific epithet, a Latin adjective, means short-necked (brevis = short, collum = neck).

Type material. Holotype: male, Namibia, Katima Mulilo District , Salambala forest, miombo and mopane woodland, 926 m elevation, 17° 50.066´S: 24°36.225´E, 18.‒20.xi.2012, Malaise trap, A.H. Kirk-Spriggs leg. ( BMSA (D)133407) . Paratype: 1 male, same data as for the holotype ( BMSA (D)133408) .

Discussion. The morphology of male M. brevicollis includes regressive features, such as small body size, reduced eyes and mounthparts, and diminished setation, which suggests adults live in a cavernous, perhaps even subterraneous environment, such as termite mounds. Also, the retracted head found in this species could be interpreted as an adaptation to such an extreme lifestyle. It is conceivable that females of M. brevicollis have reduced wings and thus are hard to obtain by Malaise traps.

Figures

FIGURE 1A–E. Miombomyia brevicollis gen. et sp. nov., males. A: Flagellomeres 12‒14, lateral, holotype. B: Flagellomeres 3‒5, lateral, holotype. C: Femur to tarsus of fore leg, lateral, paratype. D: Head and thorax, lateral, holotype. E: Wing, dorsal, paratype. Scale for A and B, 0.05 mm, for C and E, 0.5 mm, and for D, 0.025 mm. Abbreviations: cp eye = compound eye, ltg = laterotergite, plp = palpus, prn = pronotum, sct = scutum.

FIGURE 2A–B. Miombomyia brevicollis gen. et sp. nov., male, holotype. A: Terminalia, ventral. B: Gonostylus, dorsal. Scale 0.05 mm.