Arenicolus-nanos

Scientific name: arenicolus-nanos

Common name: Sand Truri

Arenicolus-nanos (sand dwelling dwarf), commonly known as the sand truri, is a small nocturnal desert burrower that stems from the ancient ambulopseculida that existed over 300 million years ago. They are around 1 foot (~30 cm.) in height and weigh around 17 lbs. (7.71 kg.). Most of their bodies are covered in tawny and white keratin fibers. Most of their bony exoskeleton has been lost in favor of this fibrous body covering to keep cool in the scorching day and to stay warm in the freezing nights. Their frontmost pair of legs still retain some of their bony covering, which is formed into a clawed appendage used for digging out their elaborate burrows. Their middle two pairs of legs are used for locomotion, the feet at the end possess two toes that spread out wide across the sand to make traveling easier. The feet have thick pads on the bottoms to protect them from the hot sand. Their hind pairs of legs have become duel purpose appendages. They are used as display structures to impress potential mates and are also used to keep the animal cool. When blood passes through the cartilaginous fin, the blood has the opportunity to cool down a bit by the time it returns to the rest of the body. This helps keep their body temperature below deadly levels. They have three spiracles on either side of their body, which are used to breathe. Sand truris have evolved basic lungs, each lung sitting on either side of their body near the spiracles. These spiracles are able to squeeze themselves shut to prevent sand and debris from entering their lungs.

Their head has two forward facing camera eyes and two sets of jaw parts. Over millions of years, their eyes went from compound eyes to camera eyes in favor of the higher visual acuity. This allows them to see very clearly and spot potential prey items. Their eyes are protected by fleshy eyelids, and also possess a secondary nictitating lid that protects their eyes from the bright sunlight and prevents sand and debris from entering their eyes. Their lower jaw evolved from a modified bony plate and as they lost their exoskeletons over many years, the jaw they possess now remains. The second set of jaw parts resemble insect mandibles, they protrude from the inner corners of their mouth and sit against the sides of their head. The inner ends of these mandibles are covered in sharp, pointed structures they use to latch onto prey. These two mandibles evolved from the two side feeding proboscises that Ambulospeculida possessed. The third feeding proboscis evolved into their tongue, which is used to detect scent. When they stick their tongue out, particles attach themselves to the tongue and when it is brought back into the mouth, the tongue runs across their jacobson's organ

Sand truris have a unique adaptation to overcome the lack of water in their harsh environment. When they do manage to find water, they drink as much as they possibly can before filling their cheek pouches with water. The cheeks are sealed off by sphincter muscles inside of their mouth, allowing water to be stored for long periods of time. These pouches allow them to quench their thirst even after leaving the water source, as well as allowing them to bring water back to their burrow to give to their offspring or other family members. Their tails are used as a fat storage for emergency energy, in case food becomes scarce.

Diet and Dentition:

Sand truris are opportunistic omnivores and will eat nearly anything they can find in their desert environment. Their primary way of obtaining food is ambushing small prey in the cover of night. Their pupils are able to grow nearly 3x the size to take in as much light as possible in the night, this allows them to see any potential prey and predators. As well as having good night vision, they use their “hearing” to detect prey. They don’t have a visible ear and they “hear” vibrations. The internal apparatus for detecting sound sits near their jaw and they can pick up the slightest vibrations through the sand.

The tooth-like protrusions inside of the mouth are remnants of the bony plate their jaw formed from. These teeth are used to eat a variety of things. The front teeth are small and sharp, pointing upright and assist in gripping onto prey. Their mandibles are also used to grip onto prey and kill it. Their back teeth are used for grinding up tougher food, like certain organisms from the Celestiphyta clade. The rearmost teeth are arranged in pads of leaf-like projections known as dental batteries. This means they have hundreds of small teeth that work together to grind food while new teeth are constantly growing in and old teeth falling out.

Reproduction and Family:

Sand truris don’t have sexual dimorphism besides males being larger on average compared to females. When it becomes breeding season, males become highly aggressive and territorial to other males. They will flush the fins on their rearmost appendages full of blood to create a flashy, bright blue appearance. Rather than having hemoglobin, their blood used hemocyanin to transport their oxygen. This gives their blood its bluish hue, and is responsible for the sand truris bright blue display. Males will travel long distances, tracking potential females. When they find females, they will wave their blue fins high in the air and let out a series of shrieks and chirps in an attempt to impress the female. If two males find the same female, they will size each other up. The bigger male with larger digging claws and brighter fins will get the female, but if they are evenly matched, they will fight. The males will bite each other with their sharp mandibles and club each other with their claws until either of them forfeits the challenge. A male can have multiple female mates at once, and once a male gets females to accept him, they will claim a territory together and dig out their elaborate burrow where they will spend most of their time. Here they will raise their young, take shelter in, store their food, and socialize in. Each female gets their own nesting burrow inside of the tunnels, where she will lay her eggs. Sand truris have evolved internal fertilization and hard shelled eggs that do not need to be in water to hatch. A female will lay a clutch of 4-8 eggs all at once, and she will incubate them with her body heat until they hatch. The family of truris are contribute to the rearing of offspring. A few individuals will go find food and water while others will stay behind and supervise the hatchlings. Family groups of truris can become very large, having as many as 15 adult individuals! When offspring is old enough to leave the burrow, some will choose to leave their families behind to find their own mate to start their own families, while others will stay behind to continue living with their parents and to assist in raising the next generation. Family groups are led by a single patriarch, which is usually the male who started the family. The level of authority then goes to the adult females, hatchings, and then any remaining adult males. All adult males besides the patriarch have the least amount of authority and are often the last to get a share of the food storages and aren’t allowed to breed with any of the females. This usually causes male sand truris to try their luck at finding their own females in the dangerous world beyond their family’s burrow.