Integrative taxonomy of a new Redudasys species (Gastrotricha: Macrodasyida) sheds light on the invasion of fresh water habitats by macrodasyids

Abstract

The order Macrodasyida (Gastrotricha) includes over 350 marine species, and only 3 freshwater species (Marinellina flagellata, Redudasys fornerise, R. neotemperatus). Herein we describe a new freshwater species of Macrodasyida, Redudasys brasiliensis sp. nov., from Brazil through an integrative taxonomic approach. The external morphology and internal anatomy were investigated using differential interference contrast microscopy, confocal microscopy, scanning and transmission electron microscopy. The systematization of the new taxon was inferred by nuclear (18S and 28S) and mitochondrial (COI) genes, and its intra-order relationships were assessed using data from most of available macrodasyids. Phylogenetic analyses yielded congruent trees, in which the new taxon is nested within the family Redudasyidae, but it was genetically distinct from the other species of the genus Redudasys. The new species shares the gross morphology and reproductive traits with other Redudasyidae and the presence of only 1 anterior adhesive tube per side with Redudasys neotemperatus, but it has a specific pattern of ventral ciliation and muscle organization. Results support the hypothesis that dispersion into fresh water habitats by Macrodasyida and Chaetonotida taxa occurred independently and that within Macrodasyida a single lineage invaded the freshwater environment only once. Furthermore, the Neotropical region seems to be peculiar for the evolution of the freshwater macrodasyid clade.

A New Species of Paraturbanella Remane, 1927 (Gastrotricha, Macrodasyida) from the Brazilian Coast, and the Molecular Phylogeny of Turbanellidae Remane, 1926

“…Finally, the inclusion of new sequences of data concerning Paraturbanella tricaudata sp. nov. and the use of distinct phylogenetic approaches did not change the scenario found by Todaro et al [44], Kolicka et al [13], and Garraffoni et al [4]. However, it is important to highlight that the low number of Turbanellidae species sequenced (from two of the six genera) may result in misleading the phylogenetic relationships within this clade.…”

“…nov.) using a QIAmp DNA Micro Kit (Quiagen, Hilden, Germany), following the manufacturer's instructions. PCR amplification was performed in a 20 µL reaction mixture containing 3 µL of genomic DNA, 13.5 µL of water, 2 µL of 10x buffer, 0.5 µL of dNTP, 0.2 µL of Taq Platinum (Quiagen) and 0.4 µL (4 pmol) of specific primers [4]. The DNA fragments were sequenced using BigDye Terminator reactions in a 3500xL Genetic Analyzer (Life Technologies, Carlsbad, CA, USA) at the CBMEG laboratory (Campinas, Brazil).…”

“…The species and respective GenBank accession numbers are listed in Table 1. The outgroup was composed of two Megadasys species and four Mesodasys species due to the close phylogenetic position of these taxa with the taxon Turbanellidae [4,40]. Each gene dataset was aligned separately using BioEdit Sequence Alignment Editor and Mafft v.7.402 (L-INS-I approach) [41].…”

“…The phylum is divided into two orders-Chaetonotida Remane, 1925 [3] and Macrodasyida Remane, 1925 [3]. The latter group is composed in its majority of hermaphroditic and marine species, which live interstitially in sandy bottoms [2,4]. The order Macrodasyida includes 10 families, 36 genera and approximately 380 described species [2,5,6].…”

Non-destructive genome skimming for aquatic copepods

“…Several works have discussed the importance of integrative taxonomy for meiofauna, with reciprocal illumination based on genetic and morphological identification (Castro-Romero et al 2016;Garraffoni et al 2019). In the past, specimens have typically been destroyed to extract DNA for molecular analyses and morphological data is thus obtained from different specimens (Di Capua et al 2017;Karanovic et al 2015).…”