A recently described octopus has such distinctive markings that individual specimens can be identified from photographs, allowing the species to be monitored in the wild.
The study, which was based on Wunderpus photogenicus, a species that was described in 2006, was undertaken by an international team of cephalopod researchers and has just been published in the journal PLoS One.
It showed that adult W. photogenicus had a unique arrangement of fixed white markings on the dorsal mantle, allowing individual specimens to be identified. The markings are not believed to be sexual characteristics, artifacts of mantle distortion or ontogenetic shifts that change as the octopuses mature.
The study said: "While body patterns are known to become more complex throughout the life of an octopus to our knowledge fixed skin components are not known to change location or expand significantly into one another in adulthood, as would be necessary to impact our results.
"Volunteers consistently matched multiple images of an individual W. photogenicus taken up to 10.5 weeks apart. Untrained observers were able to differentiate individual W. photogenicus based on photographed body patterns. Given the accuracy with which these volunteers matched individual W. photogenicus, researchers should have no problem pre-screening participants and finding skilled people to help monitor collections of images."
Wunderpus markingsThe examinations focused on the dorsal mantle area, which allowed the easiest comparison of spot patterns, and is easiest to photograph.
The scientists wrote: "As in other animals, body patterns in octopuses are constrained by fixed skin anatomy. Although their intensity and texture can vary considerably based on individual expression, the location of skin componenets and the range of pigments appear to be species specific.
"For example the presence or absence of false eyespots, 'dorsal mantle white spots', eye ornamentation, and 'lateral neck dark spots' are among many skin characteristics that greatly facilitate taxonomic identification in this group, particularly when examining photographs of live animals."
The species is commercially important, both to the aquarium trade and to dive tourism and photography, however, it has yet to be monitored in the wild.
WunderpixScientists hope to take advantage of the popularity of the species with underwater photographers to produce collaborative research on the species.
They believe that by examining photographs, scientists will be able to track individuals at popular dive sites and monitor longevity and movement patterns.
A database called Wunderpix has been set up for photographers to contribute Wunderpus images to in order to participate in the project.
For more information see the paper: Huffard CL, Caldwell RL, DeLoach N, Gentry DW, Humann P, MacDonald B, Moore B, Ross R, Uno T, Wong S (2008) - Individually unique body color patterns in octopus (Wunderpus photogenicus) allow for photoidentification. PLoS One, v3(11); 2008. doi: 10.1371/journal.pone.0003732.