Sistemática de Chironomidae (Insecta: Diptera) associados a esponjas de água doce.

Abstract

The first reports of Chironomidae in sponges date from the beginning of the 20 th century, beginning with Xenochironomus Kieffer and Demeijerea Kruseman in North America. Since then, few species in these genera have been described and it was not until 2004 that a species in another genus (Oukuriella Epler) was reported as having larvae living in freshwater sponges in the Neotropical region. In this study, we review current knowledge of Chironomidae in freshwater sponges and add new taxonomic and ecological information on these insects. In Brazil, only two genera have so far been observed in association with freshwater sponges: Xenochironomus and Oukuriella. The first of these genera has a world-wide distribution and had many species with deficient descriptions, with some of the species never having been illustrated. In this study, a revision of the recognized species in this genus was made, including re-description of several species and the description of six new species* (X. etiopensis sp. n., X. amazonensis sp. n., X. grini sp. n., X. mendesi sp. n., X. alaidae sp. n., X. martini sp. n.). Oukuriella has species with larvae associated with the sponges or with logs, and this genus was collected frequently during the course of this study. As a result, six new species* in this genus are described for Brazil (O. matogrossensis sp. n., O. digita sp. n., O. minima sp. n., O. baiana sp. n., O. rimamplusa sp. n., O. pinhoi sp. n.). Since some of the described species had larvae associated with freshwater sponges, a phylogenetic analysis was carried out to test the hypothesis that species that inhabit sponges constitute a monophyletic group. The species whose larvae inhabit sponges were grouped together, but challenges still remain to better understand the relations among the species in this genus. Among these challenges are the lack of knowledge of all life- history stages, especially the immatures, and the difficulty of obtaining specimens and determining the association with sponges because rearing the immatures under laboratory conditions is difficult.