Scuteback
Moving slightly southward into the tropics, the scuteback has become a herbivore primarily specialized to eat asterplents. While many other fauna in the area have similar diets, its exclusive herbivory has granted it an advantage in its niche.
The defining trait of the scuteback is the unique way in which most of its keratinous armor grows. Instead of growing in one solid layer across each segment, the armor is formed from many hexagonal partitions reminiscent of those covering the carapace of a turtle. These scutes no longer completely shed, instead being attached by a small area made of an especially soft and weak form of keratin. When a large predator such as the inkblot notback tries to grab it, the upper scutes will simply slough off, giving the slippery scuteback a chance to escape. Usually, two or three complete layers of scutes cover the body at a time, though each scute is only about half of the thickness of a typical neosiluro shell. If too many layers of scutes build up, the scuteback will scratch them off on a nearby tree, inadvertently leaving plenty of food for various wormback species. Though it’s hard to see at a glance, every segment except the lung, head plates, shoulders, feet, and the tip of the tail bear scutes. The remaining segments have a solid plate of keratin like that of a typical neosiluro.
While the highly muscular tentacles of notbacks are well-suited for crushing and manipulating food, additional adaptations were required to extract more nutrients from floral material. A primitive ‘gizzard’ has developed from the lower esophagus. This gizzard allows the scuteback to effectively utilize gastroliths, small rocks swallowed to aid in digestion. The gizzard utilizes powerful muscles to crush undigested asterplents with stones, pulverizing their otherwise durable cell walls. The intestine is also much longer and more coiled, giving plenty of time for all of the remaining water and nutrients to be absorbed.
With the rise of larger predators on Wright, bright coloration became a disadvantage. Early scutebacks developed a more mobile joint in the tail, along with a stiff cartilaginous rod extending from its base to its tip. This allowed the tail to be folded up in order to better regulate temperature, something that was much more important in the temperate and subtropical regions where they once lived. However, a large surface which can quickly be shown and hidden at will is essentially the perfect organ for a colorful mating display. Because of this, their bright display colors moved onto their fin, allowing the body to take on a much more drab coloration for camouflage. Whenever one scuteback desires to mate with another, it simply unfurls its tail like a colorful banner. Both sexes possess this display, though the male usually presents his tail first.
The scuteback’s short and flexible tail also makes it easier to mate. Their birth canal is slightly smaller though, so they have smaller offspring. This is remedied somewhat by making slightly more of them. Newborn larvae do not possess scutes, but after their first shed they start to develop them.