Squidworms are close relatives both to tetragnathes and armor worms. Their former exoskeletons moved under their skin and are reduced to rib-like structures, but have no real joints, being connected only by muscles and fibers, allowing them to swallow prey larger than themselves, mush like Earth's snakes. Also, their eyes are further developed than those of armor worms, but show no functional differenciation like the eyes of tetragnathes.
Squidworms mainly inhabit either lakes and rivers, feeding mainly on aquatic tentaculopods or live in the deep sea as predators and detritivores. In earlier times, they inhabited far more niches, before being replaced by more advanced true tetragnathes.

Torpedofish: An unusually short-bodied species that lives in stone reefs in large lakes.
Gobbler: A predatory, deep sea-dwelling group that can feed on prey of the same size as itself with species specialized on sunken carcasses of the larger pelagic animals.