Lunger
As more prey became available in their range, especially around Hydro (including their own close relatives!), some linzors specialized in carnivory. They became the lungers. Retaining their amphibious lifestyle, lungers honed an ambush strategy. They lie in wait, usually in rivers and watersheds, though sometimes along a shoreline. When prey comes by, often seeking a drink, the lunger bursts from the water, clasps its prey with its jaws and lateral mandibles, and drags it underwater, where it might drown or die of blood loss. The linzor mostly ate chitinous food, and the lunger still often goes for knightworms, but it's branched out to consume fellow stinzers as well, which provide heartier fare.
Lacking any large predators throughout the area, the lunger massively increased in size to fill this niche. They also spread through a massive range, all around Hydro and over to the western coasts of Barlowe and Glicker. They have not, however, crossed the deeper waters to Darwin, nor have they crossed the continental divide to reach the eastern sides of Barlowe and Glicker, where there is much more diversity, leaving them unable to get a foothold. They're comfortable in a wide range of temperatures, all the way from tropical through temperate zones.
Lungers have a sleek, streamlined body, suited both for swimming and for staying flat under shallow water. Their back legs and feet have developed more of a platform shape, suitable for sudden leaps when they thrust forward. They're camouflaged for muddy environments.
The sail is taller as well, and its spines are movable, allowing it to be raised and lowered as needed. With their wide climatic range, they need control over thermoregulation, and they also need to keep their sails hidden when waiting for prey. They also stay more underwater during extreme temperatures, hunting more actively when temperatures are mild. They retain their gills, allowing them to breathe when submerged, but if the water is poor in oxygen, they'll often angle their head upward to breathe through the nostrils at the tip of the snout.
The jaw has changed notably in response to their change in diet. They no longer need such robust musculature for chomping hard chitinous flora; their snout and lateral mandibles are much slenderer now. The lateral mandible's point are sharper, used more as barbs to pierce and grip the prey simultaneously. On the inside, there are still two types of teeth on the tongue and palate, but their function has changed. The front teeth are sharp and used much like the mandibles to latch onto prey and slice it. The back molariform teeth are used more for chewing, though the action is weak.
Reproduction remains bound to the ocean; the larvae are born without lungs and cannot tolerate freshwater.