Strikeneck Fangworm

Fangworms are highly venomous eelsnakes only very distantly related to the larger and more conspicuous sea dragons. They are the more strongly adapted for life on land of the two groups, having paired pectoral digits and a simple "wrist" that aids in climbing on land, and they have no external gill openings. Throughout the ice age they were successful but small; like salamanders, they were adapted to live in damp places, and could respire through their skin in water or damp soil, while still retaining their single lung to rely on when on land.  

Five million years into the hothouse, a lack of former competition and a vastly larger world opened up to them is allowing these fish to diversify into new niches. For now, though, these roles remain largely fossorial; adapted to much cooler conditions, most fangworms still avoid the heat that lingers at the surface as best they can, and spend their lives below ground. Even so, species are already reaching larger sizes than ever before, such as the 32 inch long strikeneck fangworm of the upland plain, a robust predator of burrowing molodonts such as poppits. 

Strikeneck fangworms are named for a specialized neck which they use to quickly reach around tunnels and bite their prey, disabling it in moments with a virulent venom. The neck consists of two dozen small vertebrae ahead of the pectoral fins, each of them loosely connected by a springy ligament. The bones in the strikeneck's neck can be pulled apart with a unique set of muscles along either side of the backbone, elongating the neck to double its contracted length in an instant and giving this predator an advantage in quickly catching its prey as it slides down into its burrow. Except for its paired fangs, fangworms have short, pointed teeth, but these are extremely sharp, and the upper and lower teeth shear together like scissors to cut flesh; fangworms only rarely swallow food whole like their snake lookalikes, and usually chew their food before hand. Though they will readily eat prey of all sizes, this lets them consume animals which would be too large to otherwise fit down their mouths, which are unable to extend in width significantly wider than their skulls. It also lets them strip off the meat and discard the longer bones and the teeth of bigger prey, which have little nutritional benefit and if swallowed would only serve to reduce the maneuverability of the hunter as it slinks off to some sheltered alcove to digest.

Feeding in this way also allows the female to feed her young; very unusually for a fish, she makes a nest in which to give birth and returns to her infants daily for several weeks with portions of her kills, which she then neatly takes apart with her teeth into bite-sized gobbets for her young to consume. This gives them a great advantage versus other fangworms which do not practice such parental care, and means they can be much more developed when they do at last leave the nest and go out on their own in the world, less vulnerable to predators. For though fangworms are highly venomous, and even this species still advertises it with a bright orange belly, their most significant predators - the fast and sometimes immune snifflers - have also survived the ice age, and some have since become specialist "snake" hunters with incredible quick reflexes and a skill for killing even the deadliest of these creatures. With such enemies around, it is strongly advantageous that the strikeneck's young get as much of a head start in growth as possible before having to leave the safety of their burrows.