December 31st’s Featured Organism: Branchiostoma lanceolatum

Branchiostoma lanceolatum

The origin of all vertebrates, you included, wasn't probably very different from this guy.

Yeah, yeah, late again; this is the last featured organism… of this year. So I wanted to commemorate our origin as vertebrates: it’s true, the lancelet (Branchiostoma lanceolatum) is not exactly the direct ancestor of all vertebrates, as once was thought; it’s part of the Cephalochordata, the sister group of vertebrates (well, unless Urochordata are the sister group of vertebrates, and Cephalochordata are the sister group of both, which lately seems to be a more likely hypothesis – the debate rages on). Still, it’s one of the closest living relatives, if not THE closest living relative, of vertebrates, and its body structure is probably very similar to the real ancestor of vertebrates. This little marine animal that burrows in the sand, filters food particles from the water and is barely able to swim clumsily ondulating its body, reinforced by a notochord, is probably not very different from the species that many millions of years ago started the radiation that would eventually originate sea squirts, hagfishes, great white sharks, goldfishes, giant japanese salamanders, snapping turtles, velociraptors, iguanas, ostriches, porcupines and humans, among the other things with a spine (or just a notochord).

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