Squaphaneer

Squaphaneers have replaced their ancestor where their ranges overlap. They are capable standing straight up like their distant ancestor the nectascooter but often walk horizontally when on the ground. The trunk is semi-prehensile and able to wrap around things such as aerial roots. They are able to use it as a third limb, both to reach across gaps and to push off of obstacles. They are capable leapers and use quick movements of their single eye to get multiple view points on a target before jumping. This, combined with acute visuospatial memory and processing enables them to generate parallax and form a three dimensional estimation of their world.

The squaphaneer has developed a septum which splits its gill pouch into two separate sections. The anterior section is still used for respiration while the posterior section is now more analogous to the inner ear of tetrapods. Sound waves from the air cause the translucent window at the rear to vibrate. These vibrations then travel through the fluid inside the chamber to an array of pressure-sensitive nerves. With the exception of the window the walls of the chamber are insulated by a layer of fat tissue which absorbs external sound and reduces signal noise. This has given them a significant edge over their ancestor in finding humflora as it means they no longer have to be in direct contact with the hum to hear its song. As a result they have replaced their ancestor in the Ramul islands.

The largest differences between adults and juveniles are internal. In juveniles the anterior gill pouch is still filled with water as it was in their ancestor. In adults however it is filled with very humid air. In the adults the gills are modified into a structure similar to the branchiostegal lung of some terrestrial crabs which both increases the amount of time they can spend out of the water and reduces their weight. While this does mean they are able to drown they are able to hold their breath for long periods of time and are capable of transcutaneous respiration. Externally juveniles largely resemble the adults though with shorter trunks and webbing between their toes.

The limbs and the auditory chamber are stiffened with a kind of pseudo-cartilage composed of a cellulose and lignin rich extracellular matrix. This pseudo-cartilage is also present in the gill filaments, enabling them to retain their shape out of the water.

Adults are euryhaline and can survive on fresh or salt water but spawning must take place in the mangal as the juveniles can only survive in saltwater. Juveniles are strong swimmers and readily disperse between the islands. Adults tend to remain on land or well above the water line in the mangal but are likewise capable swimmers. As juveniles they spend most of their time in the water but they are able to leave for short periods of time and hold their breath above water by holding water in their gill pouch.

Like their ancestor they are capable of delivering an electrical shock through the spikes on their backs. Unlike their ancestor however the have clusters of electrosensitive pits on either side of their head near the base of the trunk which let them detect when another squaphaneer has discharged its electrical defense. This helps to give an early warning should a predator be nearby and out of sight. This electrical sense is not as effective in the air as it is in the water it but it is somewhat effective if the air is particularly humid, such as after a rainstorm.