Urchins (Tripneustes gratilla) spawning! - watch
this video by Sue Kellam, taken at Kaohe Bay, South Kona,
Hawaii, Sept. 18, 2011
When viewed under bright light, this
urchin has spectacularly brilliant electric blue lines on its upper
surface. It is quite rare in Hawai`i. I have never seen a live one
here, nor even a photo of one taken in the Islands until Pauline
Fiene sent me this one, taken off Maui in 2009. At first she thought
it was a juvenile Diadema paucispinum because of its very
long spines, but when she saw it again 3 months later in the same
location and noticed that it hadn't grown, she began to wonder.
Eventually she found a photo of savignyi in Debelius and
marine invertebrate atlas and realized what it was.
Jim Petruzzi (http://www.myhawaiianimages.com/)
photographed this unusual juvenile urchin during a night dive at
Ulua Beach, Maui, at a depth of about 30 ft. in December 2011. Given
the very long spines it would have to be either Diadema paucispinum
or Diadema savignyi. The latter is very rare in Hawaii. According
to urchin expert Dr. Richard Mooi, because of the banded spines
it might be a juvenile Diadema savignyi, but not enough is
known at present to be able to tell for sure from a photograph.
More photos of juvenile long-spined urchins with size and depth
information would be helpful. Dr. Mooi says a photo from the top
directly down using flash would be best.
and Clark, 1907 ???
I found this urchin under a slab off
the Lana`i Lookout, O`ahu, at about 40 ft. Sea urchin specialist
Dr. Richard Mooi of the California Academy of Sciences tentatively
identified it from a slide as possibly belonging to the genus Centrostephanus.
Museum species list lists Centrostephanus asteriscus
as the only member of the genus present in Hawai`i. Since it is
seen so infrequently at scuba diving depths it's possible that its
center of population lies in deep water. I saw another one once,
off Makua, at about 60 ft.. It had an urchin shrimp in it.
I was scanning
the recent entries on your site and noticed the photo of Centrostephanus
asteriscus. I've also seen it twice. Once was a lone individual
under rubble at Honolua bay (around 40-50 ft). The other time was
a pair in a hole in rubble that the black coral divers had knocked
off a freshly collected colony at the Lahaina docks. Presumably,
those came from around 200 ft which would support the suggestion
of a deeper distribution.
This irregular urchin test was sitting on
the sand at about 50 ft. at Makua, O`ahu. It was larger than most
other Hawaiian species except the common Brissus latecarinatus,
but it appeared to be different. I sent the photo to Dr. Richard
Mooi at the California Academy of Sciences. He replied:
reason that the big urchin is different from B. latecarinatus
is that it seems to be a good match for Metalia sternalis.
Since some of the identification depends on things like pedicellariae
and pore-pair counts, it's a little difficult to wing it from the
photo. However, gross matching with sources other than Mortensen
(who has remarkably poor image coverage of this important echinoid)
strongly suggests M. sternalis (Lamarck, 1816).