Description of the female and larval stage of Denopelopia amicitia Dantas, Hamada & Mendes (Diptera: Chironomidae) Chironomidae)

Denopelopia amicitia Dantas, Hamada & Mendes was described based on the male and pupae collected in the Brazilian Amazon. Here we describe and illustrate the female and larva of this species. At both stages, D. amicitia is similar to Denopelopia atria Roback & Rutter, which is the only species in the genus with all life stages known until now.


Denopelopia
Roback & Rutter is a small chironomid genus with six valid species, of which only D. atria Roback & Rutter, 1988 has all life stages known. D. amicitia Dantas, Hamada & Mendes, 2016 is known as male and pupa, and all other species are known as adult male only. Based on adult morphology, Denopelopia seems to be most related to Telmatopelopia and Zavrelimyia (Roback and Rutter 1988). However, the wing C of Telmatopelopia and Zavrelimyia is slightly produced beyond R 4+5 and ends above or slightly beyond M 1+2 , contrasting with Denopelopia, in which C is not produced and ends clearly before M 1+2 (Murray and Fittkau 1989). According to Roback and Rutter (1988), the female of Denopelopia differs from that of Zavrelimyia in having the anterior end of notum slightly expanded and the ramus broader. Furthermore, the female of Denopelopia has three seminal capsules, differing from that of Telmatopelopia, which possess only two (Rodova 1971;Saether 1977). The genus has a discontinuous distribution around the world, with one Nearctic, two Neotropical, two Oriental and one Palearctic/Oriental species (Cheng and Wang 2005;Ashe and O'Connor 2009;Dantas et al. 2016).
Recently, a Pentaneurini larva collected near the type locality of D. amicitia was reared and associated with the pupa and female, which was subsequently identified as D. amicitia. In the present study, female and larva of D. amicitia are described and illustrated.
Larvae were collected associated with aquatic vegetation using an aquatic hand net. In the laboratory, they were individually reared in a 20-mL plastic vial. Chironominae larvae were provided as food every two days. For further details on rearing techniques, see Mendes (2002). Emerged adults were kept alive for at least 24 hours before being fixed in 80% ethanol to adequately preserve the coloration. The material examined was slide-mounted in Euparal ® , following the procedures outlined by Pinder (1983Pinder ( , 1986Pinder ( , 1989. The general terminology follows Saether (1980). The holotype of D. amicitia was examined to certify the identification of the reared specimen. The material is housed in the Invertebrate Collection of the Instituto Nacional de Pesquisas da Amazônia Diagnostic characters. Female: tibial spurs with three teeth, tibial comb on hind leg with six bristles. Larva: VP antero-lateral to SSm; tips of the internal teeth of the ligula directed outwards.
Legs. Foretibia 38 µm wide at apex, with one apical spur, 61 µm long, bearing three teeth. Mid tibia 38 µm wide at apex, with two apical spurs, 25 and 50 µm long, each bearing three teeth. Hind tibia 40 µm wide at apex, with two apical spurs, 30 and 65 µm long, each bearing three teeth; tibial comb with six bristles. Claws slender and distally pointed. Lengths (in µm) and proportions of leg segments as in Table 1.
Mandible. Gradually curved, 115 µm long, with three lateral setae and one sensilla. Mola distally expanded to a protruding tooth apically directed and conical; inner tooth easily visible, immediately distal to mola. A1/MD 2.52.

Taxonomic comments
A better knowledge on immature stages and the female, and a higher taxonomic resolution can support the use of non-biting midges in a wider range of fields such as ecology, biogeography and phylogenetic (Ekrem et al. 2010). However, in many Chironomidae groups, females and larvae of different species of the same genus, and even of closely related genera, are difficult to be characterized and distinguished due to their morphological homogeneity. Indeed, in many cases species-level identification of larvae and females is only possible in association with the male adult. Of the six known species in Denopelopia, D. atria was the only one with female and larva described so far, which limits the understanding of interspecific morphological differences. Females of D. amicitia and D. atria are quite similar, therefore it is difficult to distinguish them. The only observed differences were the number of teeth in tibial spurs (four teeth in D. atria and three in D. amicitia) and the number of bristles of the tibial comb (six in D. amicitia and seven in D. atria). The larva of D. amicitia is also very similar to that of D. atria, but it can be distinguished by having VP antero-lateral to SSm and the tips of internal teeth of the ligula directed outwards, contrasting with the larva of D. atria, with VP lateral or postero-lateral to SSm, and the tips of the internal teeth of the ligula anteriorly directed. It is worth mentioning, however, that the two larval features of D. atria referred above, were determined with base on illustrations and description provided by Roback and Rutter (1988) and on photos available in Cranston (2010). This is an Open Access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Distribution and notes on biology
Denopelopia amicitia is known only from two localities in the Brazilian Amazon. The larva was collected in a preserved second-order stream (sensu Strahler 1957), with sandy bottom at the sampling site ( Figure 3). Although immatures of D. amicita have been collected both in artificial (Dantas et al. 2016) and natural environments (Figure 3), they seem to be highly associated with aquatic vegetation.