One step closer to understanding the chiroteuthid families in the Pacific Ocean

Abstract

The chiroteuthid families are a clade united morphologically by the absence of a primary tentacle club and the presence of a secondary tentacle club, comprising six families: the Chiroteuthidae, Mastigoteuthidae, Joubiniteuthidae, Promachoteuthidae, Batoteuthidae, and Magnapinnidae. This study provides new information on the group’s biodiversity in the Pacific Ocean and the interrelationships among these taxa and those from other locations, using fresh and ethanol-fixed specimens collected from Japan, Hawaii, California, and New Zealand from three institutions. Sequences were obtained for the DNA barcode region (cytochrome c oxidase subunit I), 16S rRNA, and 12S rRNA, nearly doubling the available sequences for the chiroteuthid families. Although the genera Chiroteuthis and Asperoteuthis did not resolve into monophyletic clades, our analysis did find support for the ‘C. veranyi group’ and the ‘C. picteti group’—identifying additional unnamed species in both—and the mastigoteuthid genera. A close relationship was found between Echinoteuthis atlantica and Mastigotragus pyrodes, with the latter reported herein for the first time from Japanese waters. The genus Idioteuthis appears to contain at least two species, making I. ‘cordiformis’ a species complex in need of resolution. A catalogue of all specimens in this clade (representing 12 species across four families) registered in the collections of the National Museum of Nature and Science (NSMT) is also provided.