[3][4] The species name caroli derives from Carolus, Latinized name of Carlos.

[5] Subspecies include:[1] This species is widespread in the Atlantic Ocean from Iceland and the United Kingdom southwards along the Atlantic coast of Europe and Africa as far south as Namibia, the Patagonian slope, and Falkland Islands.

This bottom-living species occurs in areas of muddy substrate at depths of 40 to 1744 m.[1][6] N. caroli can reach a mantle length of 51 mm in males, while in females, the mantle length can attain 83 mm.

[9][10][11] These squids usually bury in muddy substrate during the day, emerging only at night to feed.

During copulation, the male inserts the arm (hectocotylus) specialized to store and transfer spermatophores into the female's mantle cavity.