North Pacific Diamondback Squid, Sode Ika
Described by J.E. Gray, 1828
Page authors: K. Bolstad
The North Pacific diamondback squid (or sode ika), Thysanoteuthis major, is a large muscular squid. It can reach mantle lengths of at least 100cm and is commercially fished in the waters of southern Japan and around Okinawa.
T. major is the only known species of Thysanoteuthis found in the North Pacific and Indian Oceans. Its features are very similar to those of T. rhombus and further work is still needed to investigate potential physical differences between these species.
Type locality: Ningpo (Yellow Sea, China)
Deville et al. (2024) report this species' distribution as "the North Pacific Ocean, Indian Ocean and its western limits within the warm Indian Ocean current. Reconstructed COX1 sequences collected off Galapagos Island suggest that the distribution of this species also includes the Northeast Pacific Ocean."
Test morphology
Deville et al. (2024) estimated that the T. major and T. rhombus lineages diverged around 8.6 million years ago. Their common ancestor appears to have split much earlier (about 26 million years ago) from the T. cf. filiferum lineage (South Pacific), which remains known from only a few specimens.
Thysanoteuthis major is harvested in the waters around Japan (as sode ika) and numerous studies have been published on its biology and ecology (many under the species name T. rhombus).
The complete mitogenome of this species was sequenced and reported by Tang et al. (2021) under the name of T. rhombus.
Other names