Promachoteuthis sulcus
Promachoteuthis sulcus is a species of promachoteuthid squid. It is distinguished from related taxa on the basis of several morphological features: nuchal fusion between the head and mantle, much larger size of arm suckers compared to club suckers, greater width of tentacle base than arm base, a recessed club base, and the presence of an tentacle groove.
Promachoteuthis sulcus is known from a single specimen caught by the German research vessel R/V Walther Herwig in an open net off Tristan da Cunha, southern Atlantic Ocean, at a depth of.
