Flying in the deep: the description of a new species of Grimpoteuthis (Octopoda: Cirrata: Grimpoteuthidae) from the Caroline Seamount, with ecological adaptation of dumbo octopuses

The dumbo octopus is a deep-sea benthic macrofauna belonging to the Cirrata. It is considered a primitive taxon, displaying adaptive characteristics for deep-sea environments. In the course of a 2017 survey, a single specimen of Grimpoteuthis was captured at a depth of 1240.0 m on the Caroline Seamount in the Western Pacific Ocean.

Through integrative taxonomy, this species was identified as new to science and named Grimpoteuthis feitiana sp. nov. In this study, the mitogenomes of the new species, together with another unidentified Grimpoteuthis sp. sampled from the Zhenbei Seamount, were fully sequenced. Phylogenetic analyses strongly supported the monophyly of the Grimpoteuthis and its close relationship with Luteuthis.

Grimpoteuthidae was grouped with Opisthoteuthidae, Cirroctopodidae, and Cirroteuthidae in succession. Our analyses revealed that certain residues in the mitochondrial genes of deep-sea octopods have undergone positive selection, potentially contributing to their adaptations to energetic requirements. Our study emphasizes the importance of increasing sample size to offer further morphological and phylogenetic evidence and insights into octopus adaptations to the deep-sea environment in future studies.