ITIS treats Pinnoctopus as a synonym of Octopus Cuvier, 1797. While the World Register of Marine Species treats it as a nomen dubium, has P. cordiformis as a species of doubtful validity and assigns P. kermadecensis to Octopus.1
Bieler R, Bouchet P, Gofas S, Marshall B, Rosenberg G, La Perna R, Neubauer TA, Sartori AF, Schneider S, Vos C, ter Poorten JJ, Taylor J, Dijkstra H, Finn J, Bank R, Neubert E, Moretzsohn F, Faber M, Houart R, Picton B, Garcia-Alvarez O, eds. (2017). "Pinnoctopus d'Orbigny, 1845". MolluscaBase. World Register of Marine Species. Retrieved 7 May 2018. https://www.marinespecies.org/aphia.php?p=taxdetails&id=341453 ↩