young, 4.5 mm
Aplysia argus Ruppell & Leuckart, 1830
|Maximum size: about 300 mm. (Note 1)
dusky gray to light brown sea hare dusted with white
and with anastomizing brown lines that may form irregular rings on the
sides of the parapodia. The rings appear to become less prominent with
increasing age and may be absent in large animals. (Note 2) The edges of the
parapodia, rhinophores and oral tentacles
are usually pale violet. The siphon is asymmetrically folded.
is a common species found in tide pools and shallow rocky
habitats at depths of < 1 to 2 m (< 3 to 6 ft). Rarely, it
can be found in Halimeda kanaloana
beds to depths of 10 m (33 ft). It's nocturnal and conceals itself
under rocks during the day where it can often be seen in pairs near
its egg masses. Rarely, it may rest in the open during the day at more
exposed sites. When disturbed, it ejects bright purple mucus. It
lays a tangled, light brown to greenish, spaghetti-like egg mass that
to the underside of a rock.
Big Island, Maui, Lanai, Molokai, Oahu, Kauai, French Frigate Shoals, Laysan,
widely distributed in the Indo-Pacific.
It's listed as Aplysia dactylomela Rang, 1828 in Kay, 1979;
Bertsch & Johnson, 1981; and Hoover, 1998 & 2006 (corrected in
2019 printing) as well as most other sources. (Note 3) It's
as the "white-speckled sea hare" in Hoover, 1998 &
2006. It was first reported from Hawaii in Pease, 1860 (as Syphonota grandis) and is listed as Tethys grandis in Edmondson, 1946 and Ostergaard, 1950. Alexander & Valdés (2013) consider Aplysia pulmonica Gould, 1852 to be a synonym (originally referring to the color form without well-defined rings).
Hekili Point, Maui; April 10, 2009.
Observations and comments:
Tatiana Gonnason reported an animal from Maui (seen on Aug. 18, 2020)
that she estimated as a "conservative:12-14 inches" (305-356 mm) in
length. Comparison with slate pencil urchins in her video provides rough
support for that length.
Note 2: All animals we've seen
from Kauai and the Leewards lacked well defined rings. However, we've
also seen photos of "ring-less" animals from the Big Island and the
observed specimens from Kauai were all relatively large.
Note 3: Alexander & Valdés (2013) restricted Aplysia dactylomela Rang 1828 to the Atlantic based on DNA evidence with Aplysia argus Ruppell & Leuckart, 1830 being the next available name for the Indo-Pacific population.