Diamesa martae Kownacki & Kownacka, 1980

Montagna, Matteo, Urbanelli, Sandra & Rossaro, Bruno, 2016, The species of the genus Diamesa (Diptera, Chironomidae) known to occur in Italian Alps and Apennines, Zootaxa 4193 (2), pp. 317-331 : 322-324

Diamesa martae Kownacki & Kownacka, 1980

( Fig. 4 A , B)

Some additional information to the original description are here given (the measurements given in the original description are in parenthesis).

Adult male: body length 4.7 (6.5 mm), wing length 3.62 (4.4 mm), general color of the body dark brown.

Antenna with 13 flagellomeres, non-plumose; each flagellomere with very short setae (160 µm); pedicel spherical, on its lateral side the group of 4 setae described by Kownacki & Kownacka (1980) is not visible. Eyes bare. Flagellomeres length-width ratios: (120:52, 40:40, 48:40, 40:32, 40:32, 36:28, 36:24, 40:28, 48:28, 44:28, 52:24, 52:24, 616:40), pedicel (80:140). AR (1.04).

Maxillary palp four-segmented; the length-width ratio of each segment in µm: 86.6:58, 129:52, 158:43, 188:40 (72:60, 200:60, 172:40, 220:40).

Legs: see Table 2.

TABLE 2. Lengths (in µm) and proportions of leg segments. (Legends: KP I,II,III: measurements given in the original description, IP I,II,III: measurements of the specimen from the Italian Alps; fe, femur; ti, tibia; ta1–5, tarsomeres 1–5; LR, leg ratio; BV, combined length of femur, tibia, and ta1 divided by combined length of tarsomeres 2–5; SV, ratio of femur plus tibia to ta1.)

Hypopygium ( Fig. 4 A , B; Fig. 3 in Kownacki & Kownacka 1980): tergite IX divided into two parts by a less chitinized surface passing into a short, poorly chitinized anal point, two groups of setae situated on brighter areas on the tergite symmetrically to the body axis; gonocoxite with two fairly characteristic appendages: superior volsella rounded, not clearly differentiated, inferior volsella with two lobes, an anterior dorsal lobe digitiform, well separated from gonocoxite, projecting medially, and a posterior ventral lobe elongated, adhering to gonocoxite; outer surface of the gonocoxite covered with longer hairs; two strong setae on the postero-median margin of gonocoxite; gonostylus black-brown, slender, somewhat swollen in median part, ending with apical spine, covered wholly with sensilla, with short setae on bright areas. Transverse sternapodeme with a shape intermediate between the typical arc (as in many Diamesa species, e.g. D. zernyi ) and the triangular shape characterizing species of the steinboecki group; the hook-shaped aedeagal lobe is characteristic.

Adult female, pupa, larva: unknown.

Material collected: One male from Amola glacier stream, 2474 m a.s.l., 14VIII2014.

Systematic remarks. According to Kownacki & Kownacka (1980) the determination of a group membership of this species is difficult. It belongs most probably to the Diamesa latitarsis group. The bare eyes and the structure of the hypopygium provide arguments for including it here. The gonocoxite inferior volsella is composed by two lobes, as in all other species of latitarsis group, but the shape of these lobes is characteristic in this species. The presence of two strong setae on the postero-median margin of gonocoxite and the shape of gonostylus also suggests the inclusion in the latitarsis group, whereas the sternapodeme resembles the one observed in D. steinboecki .

Figures

FIGURE 4. A, Diamesa martae Kownacki & Kownacka, male genitalia; B I, anal point, B II, sternapodeme and pars ventralis, B III, inferior volsella, B IV, gonostylus; C, Diamesa nowickiana Kownacki & Kownacka, male genitalia; D I, anal point, D II, pars ventralis, D III, phallapodeme and inferior volsella, D IV, inferior volsella and gonostylus.

FIGURE 3. A, Diamesa wuelkeri Serra-Tosio, male genitalia; B, dorso-lateral and ventro-medial lobes of inferior volsella; C, Diamesa longipes Goetghebuer, male genitalia; D I, sternapodeme, D II, anal point, D III, gonostylus.