This is *not* the ninja slug, but if you imagine that seedpod is a katana, we're 90% of the way there. OK, maybe not. Creative Commons papalars. Click for link.

As the year rounds down, I wanted to point you in the direction of a nice gallery put together by the editors at National Geographic of 2010’s weirdest new animals.

My fave: the ninja slug of Borneo. Apparently these guys shoot calcium carbonate hormone-soaked “love darts” into their paramours. Somehow this increases reproductive fitness, though whether it does so by helping lady slugs make more eggs or by putting them more “in the mood”, if you know what I mean, Nat Geo does not say. The wikipedia page seems to imply love dart hormones increase sperm survival on the part of the shooter, and that the use of the darts is fairly widespread among land snails and slugs. As with so many invetebrate systems, I’m *really glad* this is not a part of human courtship. Do not miss the gallery of love dart photos and drawings at the bottom of the page — fascinating. On a related note, anyone who has not scene the epic snail love scene (complete with opera music) in “Microcosmos” is greatly missing out. The snails look like they’re having more fun than most humans. Run, do not walk.

Taxonomically, slugs are snails that lost their shells. Like lichenization, this turn of events has taken place many times in unrelated groups, so “slugs” are what taxonomists call “polyphyletic”, or not a true, valid taxonomic group (which should always be based on a single ancestor and its descendants — that is, a monophyletic group). There are even some slugs that are still in the process of losing their shells and carry a tiny shell too small to duck into on their back, rendering them “semi-slugs”. Slugs are gastropods, which are in turn molluscs. You can see how it all fits together and who else they’re related to here. That’s it for 2010! See you in the New Year!

Image: Creative Commons Taro Taylor/dapete

While it’s only a few centimeters long, this hallucinatory sea slug — Glaucus atlanticus — makes a living doing something few other organisms dare: snacking on the “Blue Fleet”, or collection of stinging, floating filter feeders found at the surface of oceans around the world. These wind-driven organisms (which will all be covered here at some point) include the by-the-wind sailor, blue buttons, the violet snail, and, most famously, Portuguese Men o’War, Physalia physalis.

The man o’ war floats on the surface like a plastic shipping cushion, dangling streamers of nematocyte-bearing and swimmer-irritating tentacles below (remember what those are?). G. atlanticus (also known quite poetically as the sea swallow) roams about the surface, trippy belly up and silvery top down, looking for its prey like pac-man pellets (though whether the sea swallow swims to its quarry or merely relies on bumping into it is still a point of contention among scientists). The sea slug, obviously, is immune to the stings and instead stores the venom at an even higher concentration at the tip of its feathery “cerata” (singular ceras), or body projections, for use in its own defense.

The sea swallow’s psychadellic cum mathematical coloration is allegedly a classic case of “countershading” camoflauge. From above, the blue and white confuses seabirds, while from below, the silvery top/bottom appears as just another section of sea.

Here’s an interestingly-scored home-video* of a day when someone walking along the beach found the wind had driven in scores of these little beauties, and who decided to cast as many back to sea as he could find to continue their vicious (but ecologically useful) bouts of predation. Gold star for the wise use of safety sand.

Sea slugs like the sea swallow are in the Heterobranchia within the gastropods (the snails and slugs), which are themselves nested in the molluks. You can explore this section of the tree of life here.

Kudos to my friend Molly for passing on a note alerting me to this little gem. Thanks Molly!
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*Look for the bonus blue button toward the end!

http://www.flickr.com/photos/ken-ichi/ / CC BY-NC-SA 2.0 I need the bathtub toy version of this, preferably with squeaker.

I’m back alive from Hawaii (yay!) and working on an account of what happened with my planned pelagic night dive (and whether I worked up the courage to do it! : ) ). In the meantime, enjoy this photo (not mine) of a species of nudibranch that I encountered on one of my dives. It goes by the somewhat undignified name of  the varricose phyllidia, or fried-egg phyllidia (Phyllidia varicosa).

Nudibranchs (an unholy bilingual union of the Latin for “nude” and Greek for “gills” pronounced “nu’-di-brank”) are naked mollusks sometimes called sea slugs, but so are a lot of unrelated things, so wikipedia gives the impression that that is now officially frowned upon. But why even bother calling them sea slugs when nudibranch is so much fun? These organisms are among the most beautiful and psychadelically colored invertebrates on earth. Because they lack shells, they’ve developed other methods for predator deterrence, including the acquisition of several nasty toxins, stinging cells, and tentacle gestures from other organisms. Like poison dart frogs and some poisonous species of snake, caterpillar, and butterfly, being poisonous seems to work best when you are brightly colored enough to help predators remember that they hated eating you (or rather, one of your less fortunate and swiftly regurgitated kin). Here’s how the gastropods, of which nudibranchs are a member, fit into the mollusks.

Other biodiversity highlights of my dives, hikes, and trip to the Hawaii Tropical Botanical Garden included (and none of these photos or video are mine but they amply serve here) several divided flatworms; a conch that pounced on a sea urchin; hard-working sargeant majors guarding their blue egg masses plastered on rocks from hordes of ne’er-do-well marauding fish (watching this free-for-all was one of the best arguments for pregnancy that I have ever seen); a night-hunting yellow-fringed moray eel that pounced and (as per usual, I understand) missed (divers in Hawaii seem perplexed at how moray eels manage to survive); many Hawaiian lichens including shrubby reindeer lichens and pixie cups sprouting from pixie cups near the Kilauea Iki crater; the stunning native ohia trees with their brilliant red-stamened lehua blossoms; some sort of lycopod (very exciting to see in Hawai’i!), gold dust day geckos aplenty; saffron finches; Cook pines; and an explosion of Heliconias, orchids, wild gingers, ti plants (whose leaves composed the famous “grass” skirts of Hawaiians), and “Beware of Falling Mangoes” signs at the botanic gardens. Considering acquisition of “Beware of Falling Mangoes” sign.

More soon!

Slime mold sporangia (spore capsules) broken open and laid bare to the wind as nature intended. A few unopened capsules are on the left. Photo courtesy Mary Jane Howell.

At last, two actual slime molds! As hard as I searched, the best I could find were plenty of tiny white-spored objects (fungi) erupting from the wood. I learned slime mold spores tend not to be white. : ( But local slime mold expert Mary Jane Howell’s sharp eyes picked out two (not so slimy) slimes. One, a Stemonitis, often called “hair growing on wood” because of their long spore-making sacs called sporangia, had lost most of its spores and was fairly unexciting. Only the hairnet-like frame of the sporangium was left, and even that was a bit disarrayed.

But another, Perichaena corticalis (top photo), still showed the bottom half of its spherical spore capsules and a thin veneer of yellow spore dust.

I also learned there is a certain age of fallen log that is ideal for slimes — bark starting to come off, but not all off, and that looking underneath the log or bark can also bear fruit. To review, plasmodial slime molds start out as spores that hatch into amoebae or flagellated swimming swarm cells. The amoebae crawl around for a while feeding on bacteria and other microorganisms in the soil until they run into a mate.

After they fuse, they eventually start pumping out nuclei and more cytoplasm like crazy but everything stays in one big bag — the plasmodium — that crawls around until things dry out. They then produce the fruiting body, of which the spheres  of Perichaena above are one form.  When those dry out and crack open, the spores are distributed by the wind.

Fungi and slime molds aren’t the only thing I look for when I’m out. I also pay attention to lichens and plants, which have the indisputable advantage of being much more abundant and much less dependent on recent rain for viewing. I found a new (to me) species of bog or rein orchid (Platanthera sp.), pixie sticks and pixie cups (lichens, probably Cladonia sp.), and everywhere the jewel-like fiery red pendant berries of clasped-leaved twisted-stalk (Streptopus amplexifolius) of the lily family. Lilies are monocots, one of two major flowering plant divisions. These plants tend to have parallel veins and flower parts in threes — if you click on the link, notice the leaves with parallel veins and 6-petaled (tepaled, actually) flowers hanging from their twisted stalks.

Finally, we found, in turning over damp branches, several of these tiny snails. As you can see, they are plenty slimy, and plenty cute.

Do we have any invert experts here who can ID them? Here ends the tale of the slime mold hunt!