small blue spots
large cream spots
probable egg mass
Miamira sinuata (van Hasselt, 1824)
|Maximum size: 53 mm.
This species usually has a bright green body with yellow to orange
spots. However, occasional
animals may have a predominantly violet body. Irregular bright blue spots, sometimes ringed in brown,
encircle the notum just inside the mantle edge. The greenish rhinophores
and translucent tan to violet gills are finely
flecked with white. An unusual characteristic of this species is the
tri-lobed anterior end of the mantle, with the middle lobe longer than
the other two, almost giving it the appearance of having a “nose.” (Note 1)
Natural history: Miamira sinuata
is moderately rare in Hawaii (perhaps, increasing in recent years?). It
tide pools and to a depth of 27 m (88 ft) in moderately exposed to
exposed rocky habitats.
The anterior and lateral mantle lobes may contain
that produce chemicals known to repel predators. It feeds on a red
sponge with a gray-violet interior and lays a yellow, ruffled egg mass. (Note 2)
Big Island, Maui, Molokai, Oahu and Midway: widely distributed in the
Taxonomic notes: Miamira sinuata is listed in Bertsch and Johnson, 1981 as
the "jolly green giant" and was first recorded in Hawaii from Waialua, Oahu
Scott Johnson on June 10, 1978. It's listed as Ceratosoma sinuata
and referred to as the "jolly
green giant" in Hoover, 1998 & 2006 (corrected in 2019 printing). (Note 3)
Napili Bay, Maui; May 1, 2003.
Observations and comments:
1: The blue spots on a gold background aren't as precisely matched to the blue and gold ocelli found in the sea hares Stylocheilus
striatus and Phycophila euchlora as are the markings in some other possible mimics.
But, perhaps they are close enough so that M. sinuata is
still deriving some benefit from the resemblance (since the sea hares
are known to concentrate toxins from the cyanobacteria they eat)?
Note 2: Probable
egg masses found by Alexia Benrezkellah in 2021 in association with a
pair of violet animals have a lower ribbon and somewhat larger eggs
(proportionately) than egg masses associated with M. sinuata (and other Miamira
spp) elsewhere in the Indo-Pacific. Perhaps, these characters change
with age? Or, the Hawaiian population differs from the populations found
Note 3: The
presence of two distinct types of blue spotting in the Indo-Pacific
population suggests that the species might be split in the future (only
one is present in Hawaii).