One for Cali.

[Gawdzilla Sama]

Have fun, guys. http://spluch.blogspot.com/2007/05/weir ... oshop.html

[Gawdzilla Sama]

[Pappa]

That's very purdy.

[Calilasseia]

The larva is that of Acraga coa, Family Dalceridae. The adult featured, however, is more difficult to identify, because there are several very similar species in the Genus Acraga. It could be Acraga coa, or it could be Acraga infusa, along with any of the 40 species listed here.

[GeneticJen]

Closest I've come to one. Grant's Museum of Zoology in London. I do work with various gastropods in the lab, but never one of these beauties!

[Calilasseia]

Apparently that's not a true nudibranch, it's a sacoglossan. Nudibranchs never exhibit signs of a shell, even a vestigial one, at any stage in the life cycle, whereas sacoglossans have a shell in the larval stage, and some Families of sacoglossans have a shell in the adult stage. Indeed, some of them have bivalve shells! These belong to a clade known as the Oxynoacea, divided into three Families, the Volvatelliidae and the Oxynoidae, which have single, whorled shells, and the Juliidae, which have bivalve shells. All Oxynoacids feed upon Caulerpa macroalgae.

[Calilasseia]

incidentally, that mollusc, Ercolania pancerii, has since been moved into a new Genus, but I can't find the information on its taxonomic revision, for some strange reason.

[Gawdzilla Sama]

The larva is that of Acraga coa, Family Dalceridae. The adult featured, however, is more difficult to identify, because there are several very similar species in the Genus Acraga. It could be Acraga coa, or it could be Acraga infusa, along with any of the 40 species listed here.

Jerry Coyne says they're the same critter.

[Calilasseia]

An interesting paper on sacolgossans is this one:

Biogeography Of The Sacoglossa (Mollusca: Opisthobranchia) by Kathe R. Jensen, Bonner Zoologische Beiträge, 55(3-4):, 255-281 (2006) [Full paper downloadable from here]

[Guy_Montag]

Ah, Glaucus atlanticus. One of several species of Aeolid nudibranch in the Genus. All of them make their living in a very interesting way.

The Glaucus nudibranchs feed on the tentacles of ocean-drifting siphonophores, particularly the Portuguese Man'O'War, Physalia physalis. These tentacles contain powerful stinging cells known as cnidoblasts, but evolution has bestowed upon Glaucus some rather elegant features. Not only is the nudibranch capable of feeding upon the tentacles without triggering the cnidoblasts, but it passes the cnidoblats undigested, through blind cavities in the gut, and transports the cnidoblasts, still alive and ready to fire, into its own external appendages. In effect, it steals the defences of the Portuguese Man'O'War and uses them for its own defence.

As a consequence, this nudibranch is very dangerous to handle. The cnidoblasts are powerful, and being stung by the cnidoblasts constitutes a medical emergency for humans, and is life-threatening to smaller animals such as dogs or cats. The nudibranch maintains a constant live population of sequestered cnidoblasts, and is consequently extremely well defended against attack.

As the Portuguese Man'O'War has tentacles containing cells arranged by division of labour, with some tentacles being cnidoblast-armed defensive tentacles, and some being equipped with other cells (such as the shorter tentacles equipped with cells for food processing), the nudibranch obtains its nutrition by digesting immature cnidoblasts and food digesting cells, and sequesters mature cnidoblasts for its own defence. It's not the only Aeolid nudibranch to possess this sequestering feature: for example, small nudibranchs of the Genus Berghia feed upon Aiptasia anemones, and sequester cnidoblasts from the tentacles thereof. Other Aeolids feed upon other anemones, and again sequester cnidoblasts for defence. Another example is Flabellina trilineata, featured here, along with more details about the biology of these fascinating organisms.

Some other nudibranchs sequester other types of cell from their food. For example, Tridachia crispata, recently renamed Elysia crispata, is a nudibranch that feeds upon various seaweeds, and sequesters chloroplasts from its food. These chloroplasts are then maintained, alive, within the fronds on the dorsal surface of the animal, where they continue photosynthesising and providing food for the new host. This species is featured here. It's not the only solar powered sea slug, by the way, merely the best known.

I really enjoyed that, thanks

[Gawdzilla Sama]

He does get a bit terse at time, but they're always informative posts.

[Gawdzilla Sama]

A Dries bug:

[Azathoth]

You weevil bastard

[Gawdzilla Sama]

You weevil bastard

You'll notice he's flippin' the bird x 6?

[pErvinalia]