An integrative approach to assess the phylogeny and the systematics of rounded-tailed genera of the subfamily Qudsianematinae (Nematoda, Dorylaimida)

Abstract

The evolutionary relationships of rounded-tailed dorylaimid genera traditionally classified under the subfamily Qudsianematinae in Qudsianematidae are analysed and discussed with an integrative approach, including morphological features, postembryonic development and D2-D3 expansion segments of 28S rDNA gene sequences. Evidences are provided that support a closer relationship of these genera with members of Dorylaimidae rather than with other representatives of Qudsianematidae. Specifically, remarkable are the changes observed in the morphology of caudal region (tail) during the postembryonic development, with a common pattern: the existence of one or more long-tailed juvenile stages that result in short, rounded-tailed adult stage. The new phylogeny derived from such evidences does not match the current classification system, and, consequently, several taxonomic changes are proposed to improve it: eight genera are transferred from Qudsianematidae to Dorylaimidae, the new subfamily Labronematinae is proposed to accommodate them, a new classification in presented for Dorylaimidae, and emended diagnoses are given for the family Dorylaimidae and the subfamily Qudsianematinae.