Incirrate, or Finless, Octopuses are one of the two major divisions of the Octopoda, and the one most familiar to most people. Whilst many species living on coastal shelves and the upper part of the water column have been studied extensively, they are also a major part of the deep-sea fauna, although these are much less well known. The Family Megaleledonidae comprises large Incirrate Octopuses with a single sucker-row. These were originally described from the deep waters of the Southern Ocean, and for a long time were assumed to be restricted to the Antarctic, but recently have been found living as far north as Iceland, suggesting a much wider distribution.
In a paper published in the journal Zootaxa on 25 May 2026, Janet Voight and Stephanie Smith of the Negaunee Integrative Research Center of the Field Museum of Natural History, Salome Buglass of the Charles Darwin Fundación and the Department of Geography at the University of British Columbia, and Alexander Ziegler of the Bonner Institut für Organismische Biologie at the Rheinische Friedrich-Wilhelms-Universität, describe a new species of Megaleledonid Octopus from a seamount in the Galápagos Islands.
The species is described from a single female specimen which was recovered by the Remote Operated Vehicle Hercules from a seamount 25 km to the northwest of Isla Darwin, during a ten day voyage of the Research Vessel Nautilus to the Galápagos Marine Reserve. While this specimen was the only one directly examined, two other Octopus apparently belonging to the same species were observed within 1-2 km of the site where the specimen was caught.
The new species is placed in the Genus Microeledone, the first new species added to the genus since it was first described in 2004, and given the specific name galapagensis, meaning 'from the Galápagos'. As the name suggests, members of this genus are smaller than is typical for members of the Megaleledonida, with the single known specimen of Microeledone galapagensis having a mantle-length of only 31.5 mm. It is squat in form, with a head narrower with than the mantle and eyes which do not meet at the midline, and short arms, reaching only 1.4 times the length of the mantle, each of which has up to 30 suckers arranged in a single row. These suckers are tall and straight, with an approximately similar diameter along the tentacle, although they are sightly larger close to the body and slightly smaller at the tip.
Microeledone galapagensis lacks colouring on its outer mantle, but is heavily pigmented on the inner lining of the dorsal mantle muscles. This is thought to be an adaptation to its habitat and diet. In shallow-water Octopuses, pigment cells on the outer mantle allow the Octopus to change colour in order to blend in with its environment to avoid predators. All known specimens of Microeledone galapagensis were found living at depths of between 1770 and 1800 m beneath the sea surface. At these depths, there is no natural light, and therefore no need for Octopuses to camouflage themselves in this way. However, many available food species bioluminess when threatened, potentially giving away the location of anything consuming them to larger predators. The thick pigmentation on the inner lining of the dorsal mantle should hide such luminescence, thus protecting the Octopus from predation.
Interestingly, the only other known species of Microeledone, Microeledone mangoldi, lacks pigmentation on the inner lining of the dorsal mantle muscles, but has pigmented sheaths over its internal organs, apparently another way to deal with the problem of bioluminescent prey. This implies that the two species independently evolved different solutions to the same problem, which in turn suggests that their last common ancestor did not face this problem, and therefore must have lived in a different environment, presumably a more shallow one.
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