Miombomyia, 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 : 447

Miombomyia gen. nov.

urn:lsid:zoobank.org:act:75827DB3-8539-4549-869C-1C25C5B55DD5

Type species, Miombomyia brevicollis sp. nov., described below. Monotypic.

Differential diagnosis. Miombomyia exhibits most of the characters diagnostic of Amediini, notably 14 flagellomeres with simply setiform translucent sensilla and without crenulate whorls of sensory hairs, the costa lacking a break near the apex of the wing, and the gonocoxal ventral bridge largely reduced ( Jaschhof 2021). Unlike other Amediini, which lack both branches of the medial vein, Miombomyia possesses the posterior branch (M 4); and unlike the condition in other Cecidomyiidae but Catotrichinae , it enters the basal transverse vein (bm-m+m-cu, Fig. 1E ), rather than fading out basally or entering CuA ( Jaschhof & Jaschhof 2009: fig. 15). A condition unique to Micromyinae , and thus rated here as another generic character of Miombomyia , is that the head is retracted completely beneath the anterior portion of the scutum, a position facilitated through modifications of certain thoracic sclerites, such as the inward-curved, slightly sickle-shaped pronotum ( Fig. 1D ).

Etymology. The feminine name is composed of miombo, the Bemba word for Brachystegia species, and - myia, the Greek word for fly, thus meaning miombo fly.

Discussion. Miombomyia widens the range of vein patterns known in Amediini, Micromyinae and Cecidomyiidae . Moreover, the M 4 entering the basal transverse vein is a character of phylogenetic interest. The same trait is found in the relict cecidomyiid subfamily Catotrichinae ( Jaschhof & Fitzgerald 2016) and, outside Cecidomyiidae , in the ancient Sciaroidea incertae sedis group of genera (sometimes also referred to as the Heterotricha group), where it is rated as plesiomorphous ( Jaschhof 2017). The reoccurrence of this condition in Miombomyia may be interpreted as an indicator of the sciaroid ancestry of Micromyinae and Cecidomyiidae . Interesting to note in this context, the flagellar vestiture in Miombomyia , which is atypical of a cecidomyiid and different from that in other Amediini, resembles that found in Archizelmeridae , an extinct, Mesozoic family of Sciaroidea and sometimes believed to be closely related to Cecidomyiidae ( Grimaldi et al. 2003; Grimaldi & Engel 2005: 496, fig. 12.25). Grimaldi et al. (2003: 372) describe the flagellomeres of their new genus Zelmiarcha as “setulose” and “each of flagellomeres 1‒8 with pair of tooth-like scales; scales on opposite sides of each flagellomere”. Although they emphasize that “these scales have no appearance of being sensilla” ( Grimaldi et al. 2003: 372), the illustration presented ( Grimaldi et al. 2003: 372) suggests otherwise: the putative flagellomeral scales of Zelmiarcha are in the same position, and of the same size and shape, as the translucent sensilla of Miombomyia ( Fig. 1B ). Also, the fine basic vestiture on the flagellomeral nodes—referred to as setulae in Zelmiarcha and trichia in Miombomyia —is similar in both genera.

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.