The mantiskipper split from the swamp hunter, this time to specialize in hunting the slugworm, an extremely plentiful source of food. It has developed all of its body simply to hunt this small, slug-like creature.
Its previous upright walk has been abandoned, so that it could become much more stealthy. Its hunting methods have changed greatly. Instead of actively searching for food, it looks for a carcass (or rotting plant). After it finds one, it will bury itself into the carcass (or plant) and mud, and waits. When a slugworm comes around, looking for a meal, the mantiskipper just pops out, and grabs onto the worm, quickly killing and eating it. It will continue to do this, sometimes for days, or even weeks, depending on how quickly the dead thing it keeps residence in deteriorates.
The body has also changed. The front apendages are now only used for killing, and serve no purpose for locomotion. Its back legs have become much shorter, now only used for "skipping", because it does not have to actively hunt any longer, it just has to wait it out. The fins have gotten bigger, to allow it to "skip" better. Its tail is only just more than a stub now, for it no longer needs it to balance. (Although it will still swim, it is only to escape from its cousin, the swamp hunter)