Catocha brachycornis (Spungis & Jaschhof) Spungis & Jaschhof, 2017

Jaschhof, Mathias, 2017, Catochini, Strobliellini and Acoenoniini revisited: a taxonomic review of the small tribes of the Micromyinae (Diptera: Cecidomyiidae), Zootaxa 4250 (3), pp. 275-295 : 284-286

Catocha brachycornis (Spungis & Jaschhof) comb. nov.

Fig. 6A–D

Spungis and Jaschhof (2000) described the female of this species as a Strobliella Kieffer (a genus of the tribe Strobliellini , see below), puzzled by the fact that vein M1+2 was single-branched, not forked. Now the correct classification of C. brachycornis becomes obvious with the discovery of conspecific males (in one case in association with a female), whose closer examination reveals characters typical of the latipes group. In several of the specimens studied the course of the apical portion of M1+2 is unsteady, and in one specimen there is even a vestigial M2 (arrow-marked in Fig. 6D ) that branches off the nearly straight M1. This goes with the general tendency in the latipes group of M2 vanishing apically, with the apical third (or more) of M2 missing in about 50% of specimens studied, regardless of the species (see Jaschhof & Jaschhof 2009; Edwards 1938: fig. 5b–c). Characters of female C. brachycornis fit the latipes group without conflict, with the exception of the spermathecae. In previously described species, these are large, flat and partially covered with tiny membranous windows ( Jaschhof 1998: fig. 36g), while in C. brachycornis they are smaller, subglobular and without membranous windows ( Spungis & Jaschhof 2000: fig. 12C).

Diagnosis. Catocha brachycornis is the only catochine known to have a single-branched M1+2 ( Fig. 6C ). The narrow wing has a largely asetose membrane, with only a few setae scattered near the apex; the costal break is absent ( Fig. 6C ). Male genitalic structures specific to this species include: the ventral gonocoxal emargination that is U- rather than V-shaped and sclerotized marginally; the tegmen with slightly convex lateral edges and a slightly extended, narrow-rounded apex; and the aedeagal head that is provided with a pair of sclerotized appendices, each consisting of 8–10 spines of various sizes.

Other characters. Male. Body size 2.0– 2.2 mm. Head. Eye-bridge 2–5 ommatidia long, shortest at vertex. Postocular bristles 2–3, inconspicuous, situated at considerable distance from eye margin. Antenna: scape setose; pedicel asetose, slightly smaller than scape; neck of fourth flagellomere 1.7 times longer than node, node with 1 whorl of short setae basally, 1 complete crenulate whorl, 3–4 translucent sensilla distally, either simply hair-shaped or two-to three-branched ( Fig. 6B ). Apical palpal segment with small (sensory?) depression at apex. Wing ( Fig. 6C ) longer than body. Membrane smoky-brownish. Rs incomplete, present as short, weak appendix of R4+5. R-m very short. M4 vanishing proximally, extending slightly beyond bend of CuA (the long M4 depicted in Spungis & Jaschhof (2000: fig. 12A) is erroneous and includes a wing fold that follows basally). Terminalia ( Fig. 6A ). Gonocoxites: dorsal apodemes long, protruding clearly beyond ventrobasal gonocoxal margin, the latter straight or slightly concave, dorsal bridge convex. Gonostylus about twice longer than wide, pointing dorsomedially, evenly slightly tapering from midlength towards apex; apical claw large, covering most of gonostylar apex. Ejaculatory apodeme with membranous cap apically sparsely covered with large microtrichia.

Female. See the description by Spungis & Jaschhof (2000), but unlike stated there, postocular bristles are present and claws bear fine teeth, as in males. All five tarsomeres of the foreleg are provided with two multiple rows of erect bristles ventrally, the rows being broader in C. brachycornis than in other species of the latipes group.

Material studied. Estonia: 1 male (CEC380), Hiiumaa, Kerema , 7–24 May 2009, MT, R. Miller & EMTP ; 4 males, 1 female (CEC381–385), Muhu, Igäkula , 7 May–5 Jun. 2011, MT, H. Jäe & EMTP ; 7 males (CEC386– 392), Lääne-Virumaa, near Lasila , 12 May–2 Jun. 2015, MT, O. Kurina et al. & EMTP [3 males in TSPC, 3 males in IZBE, the rest in SDEI] .

Distribution and phenology. Germany, Latvia, Estonia. All the specimens known of this species were collected from May to early June in different, usually open habitats.

Figures

FIGURE 6 A – D. Catocha brachycornis, males (from Estonia). A: Genitalia, ventral. B: Fourth flagellomere, lateral. C: Wing. D: Apex of wing. Scales for A – B, 0.05 mm, for C – D, 1.0 mm.