Scyllae sp. #1
|Maximum size: 24 mm.
is elongate with four very large dorsal lobes. The margins
of the lobes may be nearly smooth or have a few short, thorn-like
projections. On close inspection short, transparent gills can be seen
on the notum. There are also a few small papillae on the sides of the
body. There are low crests on the posterior edges of the rhinophore
sheaths as well as on the mid-dorsum posterior to the lobes. There are
two color forms (with some intergrading). In one, the background color
is a nearly opaque olive green and the entire body is covered with
irregular lines of iridescent blue-green flecks. In the other, the
background color is translucent-cream, the iridescent flecks are absent
or nearly absent and the margins are dusted with brown. (Note 1)
A row of blue and gold ocelli runs down the center of the notum and
additional rows run down each side of the body in both forms. (Note
2) Also, there are evenly spaced patches of cream flecks or short
dendritic lines on the midline of the notum, on the sides of the body
and on the lateral edges of the lobes. Occasionally, cream lines
encroaching into the gold rings of the ocelli may appear bright yellow.
Rarely, there may be evenly spaced brown spots on the body. The edges of the rhinophoral sheaths are smooth.
Scyllae sp. #1
is a moderately common animal that can be found in Halimeda kanaloana beds at depths
of 5-10 m (16-38 ft). Occasionally, it occurs in association with other species of Halimeda in rocky habitats. It can swim by flexing its body laterally if
Big Island, Maui, Molokai and Oahu: also known from Papua New Guinea and Japan.
This species was first
in Hawaii from Black Rock, Maui by CP on Oct. 16, 1994. It's possible that it may ultimately be placed in the genus Crosslandia rather than Scyllae.
However, Gustav Paulay (pers. com.) found a similar population from
French Polynesia to be in Scyllae based on DNA evidence. That makes it more likely that the Hawaiian population is also in that genus.
green; 9.5 mm: Makena Landing, Maui; Aug. 2, 2002.
Observations and comments:
1: At first glance, the extremes of
these color forms look like they might be different species. However,
the body form, other elements of the color pattern and the habitat are
the same. Also, there appears to be some intergrading. To a human eye,
the two forms seem to match the colors of different groups of brown
algae (Dictyota and Sargassum?). Perhaps, the polymorphism provides better camouflage for the
species? On March 15, 2009 we observed green and translucent animals
copulating in a dish providing further support for lumping.
Note 2: The blue and
gold ocelli are virtually identical to those found in the sea hares Stylocheilus
striatus and Phycophila euchlora.
species are known to concentrate toxins from the
cyanobacteria they eat, perhaps Scyllae
sp. #1 is mimicking their aposematic coloration?