Sigh. I’ll never forget the first time I saw leafy sea dragons (a relative of these weedy sea dragons) at the Tennessee Aquarium in Chattanooga. My mom practically had to drag me out of the room.

Sea dragons are not true seahorses, belonging instead to the seahorse sister taxon (most closely related group), the pipefish. The proper name of the group is Syngnathinae, which means fused-jaw (syn-gnath), and if you look at their beaks, you can see that their jaws are indeed sealed shut. Here’s a short BBC article discussing the Life clip you just watched.

And with that, we conclude our programming for 2009. I look forward to sharing the tiny, slimy, tentacled and beautiful with you in the next decade too. Cheers, all, and stay safe this holiday season. : ) Jen

The common skate, Dipturus batis. This, obviously, is the not-up side, referred to by zoologists as "ventral" (the opposite of "dorsal"). Botanists would call it "abaxial". Image by Misjel Decleer, published under a Creative Commons Attribution Non-Commercial Share-Alike 3.0 license. Click image for link.

Just in case you thought taxonomy was a strictly useless pursuit . . .

. . . and you can see how skates fit into the rest of the cartilaginous fish (fish with cartilage skeletons like sharks) here.

Not going to win any beauty contests . . .Ateleopus purpurea. Photo by Rodolfo B. Reyes and Fishbase, distributed under a Creative Commons Noncommercial Attribution 3.0 Unported License

Jellynose fish have cartilaginous bones like sharks, though they are in the same group as bony fishes (Teleosts). They seem to have lost their calcified bones secondarily — yet another case of convergent evolution. Cartilage is a living connective tissue that pads your joints. In cartilaginous fishes, the stiff, flexible stuff is all the skeleton they have, with one big exception: the teeth. That’s why most all we have of those giant Megalodon sharks are their rather imposing choppers (in fact, that’s what Megalodon means: mega (huge-***) + odon (tooth)).

As the video says, we know very little about them because they live in the deep sea. Here’s a reasonably good hierachy of the group (see right side of page); here you can see how they fit into the Tree of Life web project (look for Ateleopodomorpha).

What do you think that jelly nose is for, other than grossing out “sensitive viewers”? Anyone?