Phylogenetic Relationships and Taxonomic Position of the Ribbon Worms of the Genus Parahubrechtia (Nemertea, Palaeonemertea) with Descriptions of Two New Species

The genus Parahubrechtia Gibson and Sundberg, 1999 was first described within the family Hubrechtiidae (class Pilidiophora) and subsequently transferred to the family Callineridae (class Palaeonemertea). Here we describe two new species, Parahubrechtia rayi sp. nov. from the Sea of Japan (Russia) and P. peri sp. nov. from the South China Sea (China). A phylogenetic analysis based on partial sequences of five nuclear and mitochondrial gene regions, 18S rRNA, 28S rRNA, histone H3, 16S rRNA, and COI, has confirmed the monophyly of the genus Parahubrechtia, and indicated a close relationship to Callinera Bergendal, 1900, whose monophyly is not confirmed. Both genera belong to the family Tubulanidae, with its junior synonym being Callineridae. Three major subclades are distinguished within the Tubulanidae: subclade Tubulanus s. str., subclade Tubulanus punctatus, and subclade Parahubrechtia + Callinera. The further status of Parahubrechtia depends on whether the paraphyly of Callinera is confirmed or not and how the problem of paraphyly of the genus Tubulanus Renier, 1804 is resolved.