Onconeura semifimbriata Saether, new combination
Creators: name: Andersen, Trond
name: Saether, Ole A.
Publisher: name: Zenodo
Year: 2005
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Diptera
Chironomidae
Onconeura
Onconeura semifimbriata

description: Onconeura semifimbriata (Saether) new combination
(Fig. 4 A–C)
Material examined. MEXICO: Nuevo León, Allende, Rio Ramos at Raices, 25°14.53'N 100°02.07'W, 20.ix.1998, 2 males, 5 pupal exuviae, net & driftnet, T. Andersen & A. Contreras­Ramos. In addition, the material mentioned in Saether (1981: 32) was re­examined.
Diagnostic characters. The male imago is separable from that of O. undecimata by having 12 flagellomeres, smaller size, and more pale coloration with distinctly ringed legs. Having a well­developed frontal seta, smaller hooklets on tergal conjunctives, and an anal lobe with 26–31 equal­sized taeniae in the fringe can distinguish the pupa. The larva has a mentum with a single median tooth and six pairs of lateral teeth (Fig. 4 C).
Remarks. The type material was based on bleached, brittle, and teneral specimens. The coloration thus was not possible to observe, the number of sensilla chaeticae was overstated, and, as seen from the material of O. undecimata, the female coxosternapodeme had not reached full sclerotization. The two males from Mexico, which also are somewhat smaller, thus are described here.
Male imago (n = 2)
Total length 1.29–1.43 mm. Wing length 0.68–0.71 mm. Total length/wing length 1.90–2.01. Wing length/length of profemur 2.68–2.71. Thorax yellowish brown, with vittae, scutellum except central parts, postnotum, preepisternum, parts of anterior and median anepisternum II, and part of epimeron II blackish brown. Legs with dark spot on coxae, fore trochanter dark, femora dark apically, base of tibiae and apex of mid and hind tibiae dark, central parts of mid and hind tibiae and basal half of mid and hind metatarsi whitish.
Head. AR 0.17–0.28. With 12 flagellomeres, ultimate flagellomere 92–94 m long. Temporal setae 2, including 1 outer verticals and 1 postorbital. Clypeus with 8–10 setae. Tentorium 113–124 m long, 11–15 m wide. Stipes 83–94 m long, 19 m wide. Palpomere lengths (in m): 26, 26–30, 41–43, 64–68, 83–94.
Thorax. Antepronotum with 2 setae. Dorsocentrals 10–12, prealars 2–3, supraalar apparently absent. Scutellum with 4 setae.
Wing. VR 1.70–1.84. Clavus 19–26 µm wide, ending 240–255 µm from arculus, with 1–2 setae at apex.
Legs. Spur of front tibia 30–34 m long, spurs of middle tibia 23–26 and 11–13 m long, of hind tibia 34 and 19 m long. Width at apex of front tibia 23–24, of middle tibia 26 m, of hind tibia 30 m. Length (in m) and proportions of legs as in Table 3.
Hypopygium (Fig. 4 A–B). Tergite IX with 16–17 minute setae, laterosternite IX with 2 setae. Phallapodeme 43–45 m long, transverse sternapodeme 24–26 m long. Gonocoxite 105–107 m long, superior volsella 8 m wide, barely joined basally. Gonostylus 39–41 m long, megaseta 9 m long. HR 2.59–2.67, HV 3.29–3.48.
Ecology and distribution. The species is known from streams and rivers in St. Vincent, Costa Rica, Guatemala, and Mexico (Spies & Reiss 1996).
description: Published as part of Andersen, Trond & Saether, Ole A., 2005, Onconeura, a new Neotropical orthoclad genus (Chironomidae, Orthocladiinae), pp. 1-16 in Zootaxa 957 on pages 13-15, DOI: 10.5281/zenodo.171214