Integrative taxonomy supports two new species of Chimarra Stephens, 1829 from Brazil (Trichoptera: Philopotamidae)

Abstract

Chimarra Stephens, 1829 is the largest genus of the Philopotamidae with about 930 species and cosmopolitan distribution. Recent taxonomic revisions have subdivided the genus into four subgenera: Chimarra, Curgia Walker, 1860, Chimarrita Blahnik, 1997, and Otarrha Blahnik, 2002, the last three restricted to the New World. In this paper, we describe and illustrate two new species of Chimarra from Brazil, C. (Otarrha) paraodontasp. nov. from Rio de Janeiro State and C. (Chimarrita) truncatasp. nov. from Amazonas and Pará states. Partial sequences of cytochrome oxidase subunit I (COI, DNA barcodes) were generated and integrated with morphological evidence to delimit the new species and evaluate their phylogenetic relationships within the genus. A maximum likelihood analysis of 48 COI sequences representing 19 species of Chimarra corroborated their subgeneric assignment based on morphology and highlighted their putative sister species. Both new species showed high K2P divergences when compared to their sister species: Chimarra (O.) paraodontasp. nov. and C. (O.) odonta (17.4–21.3%) and Chimarra (C.) truncatasp. nov. and C. (C.) simpliciforma (20.0–21.3%). These distances are comparable to the range of interspecific distances calculated for the whole genus (13.6–22.7%), adding support to their description as new species. This analysis was especially important because of the high morphological similarity of C. paraodontasp. nov. and C. odonta. Finally, analysis of the sequences of Chimarra odonta suggests that the nominal species may represent a complex of cryptic species with high intraspecific divergences (up to 18.1%), with at least two of those lineages co-occurring with C. paraodontasp. nov. at Parque Nacional do Itatiaia.