Morphology disentangles the systematics of a ubiquitous but elusive meiofaunal group (Kinorhyncha: Pycnophyidae)

Nuria Sánchez, Hiroshi Yamasaki, Fernando Pardos, Martin V. Sørensen, Alejandro Martínez

Research output: Contribution to journalArticlepeer-review

39 Citations (Scopus)


Kinorhyncha is a group of benthic, microscopic animals distributed worldwide in marine sediments. The phylum is divided into two classes, Cyclorhagida and Allomalorhagida, congruent with the two major clades recovered in recent phylogenetic analyses. Allomalorhagida accommodates more than one-third of the described species, most of them assigned to the family Pycnophyidae. All previous phylogenetic analyses of the phylum recovered the two genera within Pycnophyidae, Pycnophyes and Kinorhynchus, as paraphyletic and polyphyletic. A major problem in these studies was the lack of molecular data of most pycnophyids, due to the limited and highly localized distribution of most species, often in the Arctic and the deep-sea. We here overcame the problem by adding a morphological partition with data for 79 Pycnophyidae species, 15 of them also represented by molecular data. Model-based analyses yielded seven clades, which each was supported by several morphological apomorphies. Accordingly, Kinorhynchus is synonymized with Pycnophyes and six new genera are described for the remaining recovered clades: Leiocanthus gen. nov., Cristaphyes gen. nov., Higginsium gen. nov., Krakenella gen. nov., Setaphyes gen. nov. and Fujuriphyes gen. nov.

Original languageEnglish
Pages (from-to)479-505
Number of pages27
Issue number5
Publication statusPublished - Oct 1 2016
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Ecology, Evolution, Behavior and Systematics


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