Abstract
Metrichia is assigned to the Ochrotrichiinae, a group of almost exclusively Neotropical microcaddisflies. Metrichia comprises over 100 described species and, despite its diversity, only one species has been described from Brazil so far. In this paper, we provide descriptions for 20 new species from 8 Brazilian states: M. acuminata sp. nov., M. azul sp. nov., M. bonita sp. nov., M. bracui sp. nov., M. caraca sp. nov., M. circuliforme sp. nov., M. curta sp. nov., M. farofa sp. nov., M. forceps sp. nov., M. formosinha sp. nov., M. goiana sp. nov., M. itabaiana sp. nov., M. longissima sp. nov., M. peluda sp. nov., M. rafaeli sp. nov., M. simples sp. nov., M. talhada sp. nov., M. tere sp. nov., M. ubajara sp. nov., and M. vulgaris sp. nov. DNA barcode sequences (577 bp of the mitochondrial gene COI) were generated for 13 of the new species and two previously known species of Metrichia resulting in 64 sequences. In addition, COI sequences were obtained for other genera of Ochrotrichiinae (Angrisanoia, Nothotrichia, Ochrotrichia, Ragatrichia, and Rhyacopsyche). DNA sequences and morphological data were integrated to evaluate species delimitations. K2P pairwise distances were calculated to generate a neighbor-joining tree. COI sequences also were submitted to ABGD and GMYC methods to assess ‘potential species’ delimitation. Analyses showed a conspicuous barcoding gap among Metrichia sequences (highest intraspecific divergence: 4.8%; lowest interspecific divergence: 12.6%). Molecular analyses also allowed the association of larvae and adults of Metrichia bonita sp. nov. from Mato Grosso do Sul, representing the first record of microcaddisfly larvae occurring in calcareous tufa (or travertine). ABGD results agreed with the morphological delimitation of Metrichia species, while GMYC estimated a slightly higher number of species, suggesting the division of two morphological species, each one into two potential species. Because this could be due to unbalanced sampling and the lack of morphological diagnostic characters, we have maintained these two species as undivided.
Highlights
The microcaddisfly genus Metrichia Ross, 1938 is included in the subfamily Ochrotrichiinae, which includes Ochrotrichia Mosely, 1934, Angrisanoia Özdikmen, 2008, Nothotrichia Flint, 1967, Rhyacopsyche Müller, 1879, and the recently erected Ragatrichia Oláh & Johanson, 2011, all of them exclusively from New World
NJ (Fig. 2) and BI (Supplemental Information 4) trees corroborated morphological identification, with all 14 species of Metrichia with more than a single specimen recovered as monophyletic lineages with 100% bootstrap support
General Mixed Yule Coalescent (GMYC) analysis estimated a slightly higher number of putative species, with Metrichia circuliforme sp. nov. and Metrichia vulgaris sp. nov. being each further divided into two species (Fig. 4)
Summary
The microcaddisfly genus Metrichia Ross, 1938 is included in the subfamily Ochrotrichiinae, which includes Ochrotrichia Mosely, 1934, Angrisanoia Özdikmen, 2008, Nothotrichia Flint, 1967, Rhyacopsyche Müller, 1879, and the recently erected Ragatrichia Oláh & Johanson, 2011, all of them exclusively from New World. Based on adult morphology, Harris & Armitage (1997) and Oláh & Johanson (2011) suggested three other genera to be included in this subfamily: Dibusa Ross, 1939, Caledonotrichia Sykora, 1967, and Maydenoptila Neboiss, 1977, from the USA, New Caledonia, and Australia, respectively. Metrichia was considered as a subgenus of Ochrotrichia due to similarities of adult morphology and almost indistinguishable larvae (Flint Jr, 1968). This subgeneric status was followed by Marshall (1979), who established the New World tribe that is recognized as subfamily Ochrotrichiinae. This subgeneric status was followed by Marshall (1979), who established the New World tribe that is recognized as subfamily Ochrotrichiinae. Wiggins (1996) provided additional information on larval morphology of Metrichia and Ochrotrichia, reestablishing both as independent genera
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