Friday chaetognath blogging

The phylum Chaetognatha ("spiny jaws") consists of a few species (there are only about 120 of them) of obscure marine worms that are mostly planktonic predators, drifting with the ocean currents. Most people will have never seen one, and would be unimpressed if they had—most are small, only a few centimeters long and slender, and even the largest is only 15cm long.

Their evolutionary relationships have also been problematic, but some recent work on their mitochondrial genome takes us a step closer to resolving them.

Continue reading Friday chaetognath blogging (on Pharyngula)