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Some interesting Hawaiian octopuses not yet "officially" known from Hawai`i

CRESCENT SPOT OCTOPUS
Abdopus
sp.
      A small, fist-sized octopus typically seen after sunset on shallow reef flats and down to about 30 ft. Usually dark or mottled, the arms usually banded with white, the suckers orange (both characters clearly visible on photo 2). The suckers have scalloped (crenelate) edges on mature animals. Named for two pale, crescent-shaped spots often visible on the mantle about mid-distance from the eyes and the mantle tip (visible on photo 1, right center).
     
This animal has been called Octopus hawaiiensis in the literature, but the type specimen of hawaiiensis is in poor condition and it is unclear exactly what species it represents. Christine Huffard has collected and examined numerous specimens of this octopus in recent years; she places them in the genus Abdopus. Thanks to Adam Daw, Cory Pittman, and Christine Huffard for helping with the IDs of these photos, which were taken at night off Makaha, O'ahu, at a depth of about 25 ft.
      In older editions of my book Hawaii's Sea Creatures, the "Crescent Octopus" photo on p. 199 actually depicts the Round Spot Octopus, below. This was corrected in the 10th printing (2022).


ROUND SPOT OCTOPUS
Octopus
cf. vitiensis
     This octopus occupies much the same shallow habitat as the Crescent Spot Octopus, above, but is smaller, lighter in color, more finely patterned, and generally less common. Its arms are more slender and its suckers are cream colored with smooth edges. It often displays two round spots on the mantle, hence the common name (clearly visible in photo 1). It is active mainly at night, emerging around dusk, but specimens have been collected during the day in a shallow, completely dark cave.
       In older editions of my book Hawaii's Sea Creatures, the photo labeled "Crescent Octopus, Abdopus sp." on p. 199 is actually this species and not the true Crescent. The error was corrected in the 10th printing (2022).
       Thanks to Adam Daw, Cory Pittman, and Christine Huffard for helping with the IDs of these photos, which were taken at night off Black Point, O'ahu, at a depth of about 3 ft.


BLUE OCELLUS OCTOPUS
Octopus
sp.

Hawai`i has 15 named octopus species and this does not seem to be among them. The first one I saw was on the wreck of the Mahi off leeward O`ahu. Lisa Kasnell alerted me to it and sent a photo showing a distinct bluish ring. It was fist sized, stretched out, maybe a foot across, she said. We visited the Mahi and it was still there, in the opening of a pipe sticking up from the deck. We got it out and clipped a tiny DNA sample from a tentacle tip which we sent to Crissy Huffard at UCLA Berkeley. I thought it might be a young Octopus cyanea ("Day Octopus") but the DNA eventually came back as related to cyanea, but different
   Not long after, I saw another in a deep cave-like crevice off the Lana`i Lookout, O`ahu, at a depth of about 25 ft. and managed to get a photo (photo 2, above). Though I've been back to the same crevice several times, I never saw it again. The next sighting was in August just off the beach at Makua, O`ahu, under a ledge in about 8-10 ft. (photo 1, above). On the basis of these three sightings, it seems these octopuses are out during the day but remain in dim sheltered areas and do not roam about as Octopus cyanea does. If you see / photograph any interesting behaviors that might be useful to whoever in future describes this animal scientifically, don't hesitate to pass them on!


Abdopus abaculus?

Pauline Fiene found this octopus with long thin arms at Haloa Point, Maui, in 2008. She sent the photo to Christine Huffard, who replied: It looks like it's either Abdopus abaculus (very long arms, fairly shallow- so far found as far east as Moorea) or my runner up guess Octopus gorgonus (described from Tonga, known so far also from Indonesia and Moorea).


HAIRY OCTOPUS
Octopus sp. 16

Pauline Fiene writes: I found this in July 2013 at about 45 feet off Wailea Point. It was about the size of a dime, so fast, and displayed such a variety of postures. I wished I'd had my better camera or video. It looks like this species is on page 300 of Mark Norman's Octopus book and also I see quite a few photos of it online - if it's the same species. Crissy Huffard said that as far as she knows this species has not yet been described and has not been previously reported from Hawaii.

UPDATE: In July 2021 Roney Rodrigues sent me this great shot of a Hairy Octopus he found off west O'ahu. He estimates the size as about 7 mm (see bottom photo with tip of car key for scale). Roney posted more photos on iNaturalist and Crissy Huffard confirmed the ID.

 

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  Text and photos copyright John P. Hoover unless otherwise credited