Acostatrichia cerna Group Remarks. The four species here included in the A. cerna Group were only recently described by Oláh & Flint (2012) and they are very similar in the general aspect of male genitalia. This species group is defined by the adult male having the following characteristics: (1) segment VII with a long ventromesal process; (2) the posterior margin of segment VIII has a deep U-shaped or V-shaped incision in ventral view; (3) segment IX has a pair of long dorsolateral processes, each ending in one or more robust spines; and (4) the inferior appendages are fused to each other only in their basal area and (5) each has a long rod-like lateral process. In some morphological features, e.g. the inferior appendages with lateral processes, the conspicuous subgenital plate, the internal spines in the phallus, this group resembles species of Zumatrichia. In fact, the phylogenetic hypotheses from Bayesian Inference presented by Santos et al. (2016) indicate this, with “ Leucotrichiinae genus B” (= Acostatrichia ujasa Oláh & Flint 2012) as sister group to the Zumatrichia clade. However, this species (and others in the group) lacks the synapomorphic features of Zumatrichia, as the modified scape and the presence of preanal processes (Santos et al. 2016). On the other hand, the results of parsimony analyses presented by Santos et al. (2016) show “ Leucotrichiinae genus B” closely related to Acostatrichia species. Because of the uncertainty about their phylogenetic affinities, the original assignment to Acostatrichia is followed here, but the A. cerna Group probably constitutes a distinct lineage within the leucotrichiines.

Published as part of Santos, Allan Paulo Moreira, 2020, A review of the Neotropical microcaddisfly genus Acostatrichia Mosely, 1939 with description of a new species from Brazil (Trichoptera: Hydroptilidae: Leucotrichiinae), pp. 201-230 in Zootaxa 4755 (2) on page 219, DOI: 10.11646/zootaxa.4755.2.1, http://zenodo.org/record/3731414