#1300-1303 - Nudi Pics
#1300 - Chromodoris westraliensis - West Australian Nudibranch
for species #1300 - One of the most spectacular nudibranchs you can see while snorkeling around Perth. This one was found and photographed by Frances Hammond, who is a member of the Perth Snorkeling Facebook group I’m in. I stick to IDing the invertebrates, mostly, because some of the other members ran out of Australian birds to ID and turned to IDing fish instead, which are MUCH more diverse :) Also, I’m so short sighted that I can see anything more than a foot away when I’m snorkeling anyway :)
Anyway, C. westraliensis is a Dorid nudibranch that feeds of sponges from the Kimberley region, up on the northern coastline, down to Esperance on the south. The vivid blue black and orange colouration advertises the highly poisonous toxins that the slug accumulates from its diet of poisonous sponges.
#1301 - Goniobranchus tinctorius - Red-netted Nudibranch
A different nudibranch, again from Frances Hammond, with the photo taken at Sue’s Groyne. I have IDed this one as Chromodoris reticulata in the past, but that name is not only out of date but also had multiple synonyms already, including C. tinctorius, Doris reticulata and Risbecia reticulata.
Quite common around Perth, and a species the snorkeling group sees regularly. Apparently quite widespread in shallow waters across the Indo-West Pacific, too.
However, it also has a claim to fame noteworthy enough to get it onto the BBC news - it has a disposable penis. In fact, a penis that breaks off into three disposable sections, so it can mate again the next day, using a fresh length. The penis is also covered in backwards pointing spines that entangle sperm. The speculation is that the spines remove rival sperm, and the used length is disposed of to ensure the rival sperm don’t get a second chance in the next mate.
The research team, led by Ayami Sekizawa at Osaka City University and Yasuhiro Nakashima at Nihon University in Tokyo, watched 108 coupling to study the behaviour.
Like other Chromodorid nudibranchs, G. tinctorius sequesters some spectacularly unpleasant chemicals from the sponges it eats, and somehow manages to concentrate them in the rim and other more vulnerable parts of its own body, which probably helps it avoid poisoning itself.
#1302 - Ceratosoma brevicaudatum - Short-tailed Nudibranch
Photo by @gemfyre , Point Peron
Another reasonably common species around Perth, and much of Australia’s southern shoreline, where like the rest of the family it feeds on poisonous sponges (usually Euryspongia, at least around Tasmania). Highly variable in colour - it may be yellow, or mostly pink, and have many more spots than it does here.
I’m not clear on white the original taxonomist called it ‘short-tailed, either - seems to have a nice long tail, at least to me.
#1203 - Mystery Dorid Nudibranch?
Photo by Barbara Davenport.
As far as what species it might me, no damn idea. Seems to be in the Noumea purpurea colour group, but that includes includes ten species from the genera Chromodoris, Noumea, Pectenodoris, Hypselodoris and Durvilledoris :/
There’s a few websites out there with extensive galleries, but they’re either limited to narrow areas such as the Sunshine Coast over east, or aren’t sorted geographically at all. And the Sea Slug Forums ran out of funding the better part of a decade ago, so I can’t ask there, either.
Doesn’t seem to be common around Perth either, since it raises some comment and confusion in the Perth snorkelling and scuba groups whenever one IS found.