Spec Evo Challenge - Pelagic Xenarthra

  Here's an entry of mine for just the second of many Speculative Evolution challenges/contests from one of my all-time favorite paleo-artists, the great Hyrotrioskjan. For his second official Spec Eco challenge, the objective is to conjure up a design for a speculative fully-marine descendant of a xenarthran mammal. For those of you who aren't aware what xenarthrans are, they are basically the eccentric superorder of mammals that comprises of anteaters, armadillos, sloths, and their extinct relatives. The term "Xenarthra" means "strange jointed" in Greek, which refers to the fact that the vertebrae of said mammals possess extra articulations unlike all other groups of mammals. To be honest, I initially wasn't going to enter this challenge mostly due to the fact that at first I had no great original ideas for an aquatic xenarthran, but after seeing many of other people's entries for this challenge, I thought to myself "Screw it" and then finally managed to conjure up a brilliant idea.  


Premise:

  The nine-banded armadillo (Dasypus novemcinctus) was previously one of the most common and widespread animals throughout the Americas, ranging from northern Argentina to the southwestern and southeastern United States. This particular xenarthran is one of the most famous of the particular superorder of mammals, and is considered a pest in some states. However, in the last few centuries, populations of nine-banded armadillo had severely decreased. It was not just one factor that contributed to this sudden decrease; it was a combination of factors that led to the complete annihilation of certain populations in certain areas of the Americas.

  It is believed that disease, the introduction of jaguars from Central America into North America after the border wall with Mexico was torn down (*insert Donald Trump reference here*), climate change, and deforestation were all factors that contributed the abrupt decrease in armadillo populations.
 In certain areas of Central and South America, entire populations of nine-banded armadillo were annihilated as a result of these common factors. Conservation efforts had been made to preserve the species, but that only slightly increased the remaining amount of nine-banded armadillos on the planet.

  Meanwhile, in the wilderness of North and Central America, many of the remaining populations of nine-bands absconded to the Atlantic coastline to evade certain extinction from threats further inland. There, they began to adapt to life along the sandy Atlantic seaboard. The remaining nine-banded armadillos soon began to substitute their customary diet of insects, eggs, and plant matter for anything edible they could find on these beaches, including beach grasses, ice plants, crustaceans, shellfish, and even carrion.

  Within the thousands of years after humanity departed Earth in search of other habitable planets to colonize and expand territory, these armor-cased mammals started to evolve to adjust to a marine environment, slowly and steadily adapted to an ocean-oriented lifestyle. Their omnivorous diet became replaced with a fully carnivorous diet of small marine life, their keratinous shells became more like that of a turtle's shell, and their limbs transitioned from feet with large digging claws to paddle-like flippers for propelling themselves through the water. Eventually, after a few million years, the armadillo transformed from a terrestrial armored xenarthran to a fully-aquatic marine mammal that had no need to revert back to a land-based lifestyle.

This takes us to completely new species of mammal: The marine turtdillo (Thalassodasypus pseudochelys).



Description:

  The marine turtdillo (Thalassodasypus pseudochelys) (sometimes referred to as the "turtle mimic" or "mock turtle") is a small aquatic armored xenarthran mammal, and a descendant of the nine-banded armadillo. This eccentric mammal can be found swimming the shallow, sunlit waters throughout the Gulf of Mexico, Caribbean Sea, and Sargasso Sea, mainly around mangrove forests and coral reefs. The marine turtdillo was named chiefly due to the fact that it superficially resembles a sea turtle (a few species of which had been hunted to extinction by humans) in anatomy, as it seems to retain the keratinous shell composed of bony dermal scales of its terrestrial predecessor and its limbs have become more paddle-like in appearance. Nevertheless, unlike sea turtles, the marine turtdillo dissents by being "warm-blooded", possessing cheeks as opposed to a horny beak, and giving birth to live young instead returning to the land to lay eggs.

  The marine turtdillo's diet is mainly crustaceavorous, a diet that usually comprises of smaller crustaceans including shrimps, prawns, and young crabs or lobsters. However, this aquatic xenarthran has also been observed feeding on small fish and immature cephalopods. To capture said delicacies in coral nooks and crevices, the marine turtdillo deploys a primitive form of underwater suction (as seen above) by quickly opening its jaws and sucking in water, along with any edible organisms it may discover. Afterwards, any water that it just so happened to suck in is forced out via its nostrils.

  The marine turtdillo, akin to its terrestrial predecessor, is ordinarily a secluded and shy animal, most active at dawn, dusk, and night when it moves shallower waters into deeper waters to forage for potential prey. When not rummaging for prey, the turtdillo usually keeps a watchful eye out for potential hazards (its eyesight is more well-developed than the nine-banded armadillo). Although its keratinous shell is enough to protect from the bites of many smaller predators, this aquatic xenarthran can swim away at surprising speeds away from larger predators that pose a greater threat to its survival, including sharks, pinnipeds, and large carnivorous cetaceans.

  The marine turtdillo, similar to other marine mammals, gives birth to live young. The breeding season for turtdillos occurs during a two to three month period of time, typically lasting from April to June. During this time, males will often vigorously compete for mating rights, even attempting to dislodge other males from the back of a female while mating. Following a gestation period of around three months after mating, a female turtdillo will give birth to a single pup in shallow water, where after being finally born the pup must quickly race to the surface for its first breath of air. Subsequent to doing so, the pup will spend the next four to six months with its mother, feeding and growing off her readily-supplied milk. Usually after a few months, the young turtdillo will begin to transition from a diet of mother's milk to a diet of crustaceans, small fish, and cephalopods. After about eight months (near sexual maturity), the pup will ultimately depart from its mother to live a life of its own, and hopefully pass on its genes to the next generation.



And there you have it, folks! My very own rendition of a pelagic xenarthran! This description was a pain to type, but on the bright side, I'm finally finished and just in time for this challenge to end! This second Spec Evo Challenge ends today, so any of you have entries that need completion, you'd better hurry!

Anyways, I hope you like it everyone! Especially you, Joschua! It was a pleasure to once again be able to participate in these Speculative Evolution challenges/contests that you're doing! When the next one comes around, I'll be ready for it!