Micromacrocera L. PAPP 2008, gen. n.
Creators: name: Papp, L
Publisher: name: Zenodo
Year: 2008
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Diptera
Keroplatidae
Micromacrocera

description: Micromacrocera L. PAPP, gen. n.
Type species: Micromacrocera stenobasis L. PAPP, sp. n.
Gender: feminine.
Etymology. This is the smallest species of the subfamily Macrocerinae.
Frons (postfrons) short oblique, cerebral sclerite large, occupying all dorsal part of head. Cerebral sclerite with some scattered setae. Occiput and postgena large. Eyes comparatively small, occupying less than half of the head in profile (Fig. 1). Three ocelli, anterior one forward, posterior ocelli dorsally directed. Pilosity of eyes distinct (Fig. 1). Face and clypeus separated by a rather broad membranous aperture. Face very short, in this respect it is similar to that of Macrocera spp. Clypeus high and comparatively narrow. Foramen small.
Antenna in all probability with 14 flagellomeres, but only 10 can be seen on the specimen (left side, on the right side only 8), apical flagellomeres lost. Scape comparatively long, ventrally with longer setae, pedicel globose. Flagellomeres (Figs 3–4) simple, cylindrical. Hair-like setae (cilia) of flagellomeres rather long, on the 10th flagellomere they are longer than diameter of flagellomere (Fig. 4).
Mouth-parts rather small, labella small, fleshy. Maxillary palpus with four palpomeres but seems 3-partite, since palpomeres 1–2 partly fused (Fig. 2).
Thorax (Fig. 5) small, height at middle (without coxae) only 0.50 mm (Fig. 5). Structure of thorax unusual: mediotergite largely dorsal, laterotergite not large but continued dorsally. Scutellum bulging, minute, 0.07 mm only. (I saw only 4 setal bases on scutellum, almost dorsal ones, i.e. not marginals; scutellum otherwise microtomentose only).
Wing (Fig. 15) membrane without macrotrichia and with microtrichia evenly distributed but wholly irregular. No strong costal fringe. Costa thick, reaches 3/4 of distance between R 5 and M 1. Longitudinal veins (incl. Cu1) setose dorsally, medial stalk (M 1+2) free of setae. R 4 absent but a small thickening on R 5 represents base of R 4. M 1 and M 2 not completely reaching wing margin. Base of M 3 not pigmented. Cu 2 and A 1 present as short indistinct parallel brownish folds on wing base (to the level of R-M fusion only). A 2 not discernible at all. No alula present between anal angle and wing scale, and even almost no alular region on wing. Prealular (basal) region with a straight margin (Fig. 15).
Halter simple, knob not too large.
Femoral and tibial setulae simple, fine and rather long, and not ordered into rows. Fore coxa medium-long, the middle coxa short, the hind coxa very short (Fig. 5). Tibial spurs 1+2+1, i.e. posteroventral spur on hind tibia missing (at least I was unable to find its base even under a higher magnification). Fore tibia antero-apically without a large depressed or even emarginated area (Fig. 6), and with a row of 5 medium-long pointed setae, similar to some Sciaridae (e.g. Bradysia), rather than to any other Macrocerinae.
No anterior or posterior combs of small thornlets on mid and hind tibiae (Fig. 8). Tarsal claws simple, very small, and straight, except for apical part. No developed pulvilli; they are as hairy as empodium (Figs 9–10).
Abdomen with 8 normal preabdominal (pregenital) segments. Both tergites and sternites broad, in each segment tergite and sternite almost meet laterally, i.e. intervening membranous area rather small. Spiracle pairs 1–7 are situated in membrane. Tergite 8 (Fig. 11) not much shortened, sternite 8 short, not much more than half as long as tergite (0.57x). Tergite 9 comparatively long, anterior edge broadly emarginated, caudally largely pentagonal (Fig. 12). Cerci comparatively large and broad with 2 pairs of rather short apical setae.
Male genitalia rather small. Left and right gonocoxites fused but on a short ventral section only (Figs 13–14). Genital structures in three layers (from ventral to dorsal): gonocoxal fusion, parameral complex, and most dorsal, just under tergite 9, gonocoxal apodemes with their fine plate (see below). Medial wall of gonocoxites less long (high) than breadth of gonostylus. Parameres with long lateral arms joining long gonocoxal apodemes. Sclerite connecting parameres with basiphallus very short compared to that of Macrocera spp. Phallus (distiphallus) membranous, disintegrated when treated with sodium hydroxide. The medial slightly asymmetrical sclerotized structure, ventral to the level of tip of parameres and gonocoxal apodemes, must be regarded as ejaculatory apodeme. There are 2 pairs of parameral lateral arms: one dorsal, connected to gonocoxal apodemes; the ventral pair as long as dorsal one, completely overlapping it, (Fig. 13), slightly ventrally curved pair of processes may support phallus. Gonocoxal apodemes connected by a lamina, which is distinct though not strongly sclerotized, and, that connects gonocoxal apodeme apices with basiphallus (not seen in Macrocera). Inner wall of gonocoxites almost complete, i.e. ends not far from base of gonostylus with a basal lateral process; lateral half of the apex of gonocoxites with a U-shaped emargination, which allow moving the apex of gonostylus laterally. That inner (medial) wall plain, i.e. not concave as in Sciarokeroplatus (see PAPP & ŠEVČÍK 2005) and present not far from gonostylar base, contrary to Sciarokeroplatus.
description: Published as part of Papp, L, 2008, Micromacrocera Gen. N., The Smallest Macrocerine Fly (Diptera: Keroplatidae, Macrocerinae), pp. 13-21 in Acta Zoologica Academiae Scientiarum Hungaricae 54 (1) on page 14, DOI: 10.5281/zenodo.5731880