Macrotritopus equivocus

Macrotritopus is a poorly known genus of octopuses in the family Octopodidae. As it stands, Macrotritopus contains two valid described species, Macrotritopus defilippi from the NE Atlantic and Mediterranean, and Macrotritopus beatrixi from the Caribbean and SW Atlantic. Two poorly described, unresolved taxa are known only from planktonic hatchlings (Macrotritopus equivocus and M. scorpio), and a further three undescribed Indo-Pacific species may be attributable to this genus.
The genus Macrotritopus was described by Grimpe (1922) for the single planktonic specimen of Octopus gracilis Verill, 1884, the name referring to the very long third arm pair on the paralarvae. Given that O. gracilis Verill, 1884 was a junior homonym of O. gracilis Souleyet, 1852, authors Joubin & Robson (1929) replaced it with Octopus (Macrotritopus) equivocus, with Macrotritopus regarded as a subgenus at that time, these authors also described M. danae. For a time these Macrotritopus species (all known from paralarvae) were misidentified as juveniles of Scaeurgus unicirrhus. Researchers in the late 1970s/early 1980s proved that Macrotritopus paralarvae from the Atlantic grew into the previously described Octopus...