Dataset of paper "Improved taxonomic and gene sampling advance the knowledge ofdeep relationships within Macrodasyida (Gastrotricha)", DOI: cla.70013

Advances in Macrodasyida (Gastrotricha) phylogenetics, fueled by new species discoveries and molecular data, are reshaping taxonomic classifications. Molecular analyses suggest polyphyly in Cephalodasyidae and Macrodasyidae, yet insufficient sampling continues to obscure precise relationships. Our study seeks to enhance the resolution of Macrodasyida’s internal phylogeny through expanded taxonomic and molecular sampling. We obtained 66 new sequences from 21 macrodasyidan species, integrating them with published data. Our dataset includes representatives from nine Macrodasyida families and 21 genera, alongside two chaetonotidans. We analyzed the concatenated sequences of three genes (<i>18S</i>, <i>28S </i>rRNA, <i>COI </i>mtDNA) from 51 terminals using Maximum Parsimony, Maximum Likelihood and Bayesian Inference. Our findings confirm the polyphyly of Cephalodasyidae. <i>Dolichodasys</i> and <i>Paradasys</i> cluster with Redudasyidae, while <i>Cephalodasys</i> and <i>Mesodasys</i> form unrelated lineages. <i>Cephalodasys mahoae</i> is nested within <i>Paradasys</i> rather than <i>Cephalodasys</i>, suggesting an original misidentification. The phylogenetic placement of <i>Pleurodasys</i> remains uncertain. Macrodasyidae is non-monophyletic, with <i>Urodasys </i>forming an independent lineage. The first molecular data ever obtained for <i>Dendrodasys</i> hint that the family Dactylopodolidae is likely polyphyletic as well. We propose an updated classification of Macrodasyida, introducing Mesodasyidae fam. nov., Urodasyidae fam. nov. and <i>Paraurodasys</i> gen. nov. Furthermore, we reassign <i>Dolichodasys</i> and <i>Paradasys</i> to Redudasyidae and <i>Cephalodasys mahoe</i> to <i>Paradasys</i>.