Cladistics: Monotoalosia (Kadriomorpha)

Among modern Anisospondyls, there are few as diverse as the Eusymmetrodactyla. The bulk of their species and diversity comes from their flying members, the Stauropterygians, which were obviously able to disperse and diversify around the globe quite easily.

But the second most successful group of Eusymmetrodactyls is nothing to scoff at either. 

The Monotoalosia are often considered to be the dominant macrofaunal herbivores of Eryobis. They can be found on every major landmass except Rubiëra and are usually counted among the megafauna wherever they exist.

The Monotoalosia are a rather odd looking group, even for Eryobian standards, and have an interesting but unexpected evolutionary past. Genetic testing and paleontological evidence suggests they split off from other Eusymmetrodactyls shortly after the Stauroptergyians split off, possibly placing their origin as early as the start of the Recrescian, some 106 million years ago. Their earliest and most basal members seem to have been small, gliding, rodent like animals and curiously, one family of these most basal members survived to modern times in the tropical rainforests of Bloëca, the Paleovolyidae.

The revelation of Paleovolyids as Monotoalosians was a quite recent one. It was previously assumed that they were members of Polyotoalosia that simply had only one pair of auricular filaments and a beak at the end of their mandibles. But a reexamination of their foot anatomy, in which their front feet are oriented "sideways", and some molecular testing revealed that they were in fact closer related to Kadriomorpha than to any other Eusymmetrodactyls. 

It would be this discovery that led to the answer of a question that scientists had been asking since the very beginning of Eryobian exploration: how did Kadriomorphs get those odd traits?

Indeed, Kadriomorpha are ranked among the strangest looking of Anisospondyls. But not for their alien looks, no rather for the fact that they don't look like aliens. Their appearance has a lot of similarities with hoofed animals from Earth and like them, Kadriomorphs are almost all completely quadrupedal with heavily reduced visendal front limbs. Often all that remains of their former front limbs is a long spike like claw, sprouting from their shoulders.

No one could figure out why until Paleovolyids were revealed as their cousins and the group Monotoalosia was officially created. The Kadriomorphs inherited their traits from ancestors that were specialized in gliding.

It is speculated that Kadriomorphs evolved from Paleovolyid like creatures that left the trees and instead decided to make a living on the ground. They would have used their caecal front limbs and hind limbs to walk, while their visendal front limbs supported the patagium and were likely held off the ground.

Soon they would have lost the ability to climb and glide completely in favor of a terrestrial lifestyle.

Some of these early Kadriomorphs would have used their former wing arms to grab and manipulate food, eventually leading to modern creatures like the Nothrungulatids.

Others were reducing the wing arms and elongating the claws to serve as defense weaponry to attacks from above. Prokadrians and Bounindriids are leftovers from this stage.

As Kadriomorphs were becoming more and more adapted to a cursorial lifestyle, the visendal limbs became more reduced, their other legs become longer and stronger and their claws would become hooves. They became the Kadrians.

The Kadrians are easy to recognize. They often bear an uncanny resemblance to terran herbivores like antelopes, rhinoceroses and horses. 

The most basal Kadrians are the aptly named Protokadrids. These creatures are some of the only Kadrians alive that still walk on their toes and just their hooves and sport visendal limbs that still very much resemble hands with long claws. Some scientists doubt whether Protokadrids aren't even true Kadrians at all and not just advanced Kadriomorphs because of these primitive traits.

All other Kadrians share a number of traits that distinguish them from Protokadrids. The most noticeable of these are their completely unguligrade feet and visendal limbs that have been reduced to nothing but a single metacarpal that supports a large claw. 

Or so we thought. 

Turns out there are two families of Kadrians that do not conform to these standards. The Lagokadrids of Tlèëa have two digits and thus two claws on their visendal limbs and the Camelokadrids of western Miesjeta also still have two visendal claws and do not walk on their hooves, rather being digitigrade.

Because of this, a new group was made: the Eukadria, the true Kadrians. Besides all the aforementioned traits, Eukadrians also all share a large and well developed, chambered digestive tract that extends beyond their hips and makes the base of their tails look bulbous. In addition to their beaks, they have highly specialized linguopalatal jaws that are very long for Cryptognath standards. This second pair of jaws is able slide and can move both back-and-forth and up-and-down, making them extremely efficient in chewing tough plant matter.

The Rhamphoceratids are the most basal of the Eukadrians. In the past, this family also contained a number of gracile genera that resembled other Eukadrians more, but nowadays the Rhamphoceratids are large bulky animals that are the most massive of the living Kadrians.

Eukadria knows two major branches that are ever so slightly more related to each other than either is to the Rhamphoceratids. The less "derived" of the two are the Plesiokadria. These are typically stocky and heavy set animals with primitive hooves.

The other branch, the Neokadria, on the other hand are the more typical animals people imagine when they hear the word Kadrians. They are gracile, slender legged, often vaguely deer or antelope like animals that put all their body weight on a single hoof per leg.

Curiously, the hippopotamus like Lurdukadrids of Hatèmica have recently been proven to be more closely related to Neokadrians than to Plesiokadrians, despite bearing a greater resemblance to the latter. 

The Kadrians and Eukadria as an extension are a very old clade, which is best exemplified by their peculiar global distribution.

Back when Kadriomorphs first started appearing, the landmasses of Guralta, Lachoba, Hatèmica, Bloëca, Azchèda and western parts of Tlèëa were united in the supercontinent called Kwispuul. This may partially explain why some relatively closely related groups can be found oceans apart. 

Eukdria appear to have their origin in Guralta, which is where the Rhamphoceratids, a number of Plesiokadrians and basal Neokadrians can be found.

It seems however that some groups like the Acanthatheriids and Lurdukadrids managed to get to other continents before Kwispuul had fully broken apart.

But then there the Embolokadrids of Hatèmica and the Ceratokadria of Miesjeta. The molecular clocks of these groups suggest that they only appeared after Kwispuul was already supposed to have broken up. 

Some scientists suggest that the ancestors of these groups rafted over, but given the nature of Kadrians, that is rather unlikely. 

Most seem to believe in the theory that there must have been island chains or temporary landbridges connecting Hatèmica and Miesjeta to Guralta at some point in the past, and that these wayward Kadrians island hopped to their current locations.

In the last few years, researchers added a new and highly unexpected member to the Monotoalosia family tree: the bizarre Bouvijasiren.

This cat sized aquatic creature was for a long time, and due to a lack of proper studying, considered to be a Brachiostomatan because of its arms located below its mouth. An actual proper examination of the animal however revealed that it was not a Brachiostome at all, but rather a Cryptognath. Not just any Cryptognath too, but a relative of the Kadriomorpha whose closest living relatives appear to be the gliding Paleovolyids.

How exactly this odd critter evolved or where it came from is not yet understood, although some fragmentary fossil evidence seems to hint at it being the last relic of a once more diverse group. All that is currently known about it is that it lives exclusively in brackish and freshwater systems of the island called Bouvija and its surrounding smaller islands in the farsouthern regions of Rubiëra.

Cladistics: Arachnopoda

There are few creatures as synonymous with the name Eryobis as the Arachnopods. These aptly named eight legged terrestrial vertebrates can be found in nearly every corner of Eryobis and are perhaps even more recognizable than the Anispondyls they share the land with.

Nearly all Arachnopods share a similar basic body plan as they all have vaguely tetrapod like heads on bodies supported by eight spider like legs. But they are no tetrapods, nor are they even closely related. Matter of fact, they're not even Sarcopterygians. They are ray-finned fish of the order Holostei, which on Earth were represented by bowfin fish and gars.>

Arachnopods look rather little like their terran counterparts however, so how did they come to be?

Arachnopoda are part of the Octopodichthyes, a member of the "spiderfish" clade. It is hard to determine if spiderfish are a natural group or if its various members evolved their legs independently since we only observe one other taxon of spiderfish alive today, and those have four legs instead of eight.

Spiderfish in general often fossilize poorly, so we do not know a lot of their early history compared Planosolincolans, which tend to fossilize a lot better.

It is theorized that spiderfish evolved their legs when they separated a number of pelvic finrays from the main fin in order to prod the sediment for sustenance. This would have later led to them moving around on their free finrays until they developed into proper ossified legs. 

At some point, probably in the late Narthian period, some Octopodichthyans made their way to land and would give rise to the Arachnopods we are familiar with today.

As their legs sprouted from the pelvic girdle, Arachnopods needed to hypertrophy their hips in order to support their weight on land. Their pectoral fins on the other hand atrophied since the no longer really served a use on land. 

Many Arachnopods heavily reduced them or lost them completely, while one group known as the Osteotarida modified their pectoral fins to aid in detecting sounds, essentially turning them into ear pinnae.

Because of their massive pelvic girdles, that sometimes heavily resemble the plastrons of turtles, Arachnopods usually have rather stiff torsos. Their eight sprawling legs somewhat negate this issue however, since they provide the animals with a lot of mobility in several directions.

A rather peculiar feature of Arachnopods are their skulls. More specifically, their jaws.

Many Arachnopods have a unique jaw mechanism wherein both the maxilla, premaxilla are separated from the cranium and a dentary that is not connected to the rest of the mandible.

The maxilla is connected to the cranium with a joint that allows it to swivel and is able to slide in a groove in the mandible where a number of muscles and tendons connect to it, creating a "deadbolt mechanism" where the jaw can be locked at a certain angle.

When the maxilla swivels, it usually also causes the premaxilla and dentary to move.

We do not completely understand why this strange jaw mechanism evolved, but we do know that it adds a lot of strength to their jaws opening and closing.

Modern Arachnopods can for the most part be categorized as belonging to one of three groups: Dactylourae, Euarachnopoda and Pulvinopoda.

While the first two likely descend from a single ancestor that survived the catastrophic mass extinction known as the World Scarring, Pulvinopoda appears to have come from two distinct survivors of that cataclysm. Of these two lineages, the Neopulvinopods are the most successful and widespread while Polytryposternians are quite restricted in where they occur nowadays. Hence why Arachnopods are typically placed in one of three categories instead of four.

Pulvinopoda are considered to be the most primitive of the living Arachnopods. They are all ectothermic, often scaleless, amphibian like creatures that lack ear pinnae. Calling them basal would be an insult however. Their skull morphology is highly divergent from the earliest Arachnopods and has close to zero resemblance to those of the other Arachnopod groups.

The Dactylourae are perhaps the oddest of the Arachnopods. These almost exclusively arboreal creatures are most easily recognized by the claw at the end of their tails. While a number of basal genera still exist, most Dactylourans can be placed either within Kremasmasauria or Aioratheria. 

Kremasmasaurs are reptilian or and serpentine in appearance and often completely lack ear pinnae. 

Aioratheres are homeothermic and are typically covered in filaments, which are actually hair like keratin projections of the scales underneath.

Where the other Arachnopods ruled the land, the Dactylourans adapted by specializing in the arboreal lifestyle, being among the very few Arachnopods with an affinity for climbing.

The Euarachnopods are what most explorers first image when they hear the word Eryobis.

These Arachnopods tend to grow much larger than their other relatives, live mostly on the ground and are not dependent on close proximity to water for survival, so they are often much more easy to spot.

While basal Euarachnopods look rather similar on the outside, one can quickly determine their origin by examining their skulls. Usually, they can either be placed in Pseudozygomia or Panhesparachnes.

Both these groups have a temporal fenestra in their skull, but they evolved them independently and from different structures.

Pseudozygomians evolved a fenestra by closing a section of the oral cavity in order to create more muscle attachments and to reinforce the skull. Pseudozygomians can mostly be found in the eastern hemisphere of Eryobis, existing in parts of Tlèëa, Lotharca and Rubiëra, with the subgroup Rubiarachnes being almost exclusively restricted to Rubiëra.

Panhesparachnes evolved their fenestra by forming a bony ring to give more support to the eye and thus essentially splitting the orbit in two. Basal Panhesparachnes often don't have a completely formed fenestra, but all members of Arachnotheria do.

Arachnotheres, the famous spider beasts of Eryobis, are fully endothermic and like the Aioratheres, are covered in hair derived from thin projections on their scales.

Arachnotheres can be found on every continent except Rubiëra and possesses a great number of families, but most of them can be placed in Bloëcatheria, Kentrotaria or Hesparachnes.

Perceived rodent analogues

Among small endothermic animals, a rodent like bodyplan has appeared many times throughout history. Think about mammals like rodents, hyraxes, lagomorphs, multituberculates, diprotodonts but also synapsids like dicynodonts and many more that have evolved to be small, mostly herbivorous critters, often with equipped with large incisors or beaks designed for cutting.
It should therefore come as no surprise that a similar phenomenon of convergent evolution can be seen on Eryobis. So far we have recorded seven groups of rodent analogues on Eryobis that all evolved independently. Among the Arachnotheres there are three, and among the Anisospondyls there are at least four.

The creatures depicted here are all generalised forms of with characteristics most often seen in members of their clades.

Top row, left: All members of this group of Arachnotheres, named Kentrotaria, appear to have feet split in the middle tipped with a number of smaller claws. Their tails are usually fairly long and their ears are tipped with venomous spurs that can break off and regrow.

Top row, middle: Not quite Arachnotheres, there appears to be a group of Dactylourans, called Scalprodensida, that fill niches comparable to squirrels and other arboreal rodents and to some extend, primates.

Top row, right: Dubbed Cathetirhinoids, these curiously shaped Bloëcatherian Arachnotheres are a surprisingly common sight around our settlements in western Miesjeta, seemingly attracted by our activities. These typically small creatures have two long probe like nostrils that sport long whiskers. They have great control over these appendages and can often be seen vigorously moving them while they look for food like a pair of antennae.

Bottom row, left: By far the most well documented rodent analogues of Eryobis are the Triprotodonta, called “Dozjemoigh” by the natives. These creatures are found on every major landmass except for Hatémica and like actual rodents, can vary in size from a small mouse to several hundred kilograms. Triprotodonts are one of the three major clades of the Liomedactylae, the terrestrially dominant group of Trapezostome Anisospondyls and are quite odd at that. Their inhaling spiracles are pointed outwards and their auditory plates are flat and circular. But their most defining trait is their mouth. Like the aquatic Fermourodonts, they have convergently evolved their jaws to work as three mouth parts, with both mandibles coming down on the trapezium below them. Each of these mouthparts sports a single tooth at the tip, earning them their name.

Bottom row, middle left: There appears to be two different kinds of rodent like Effingodactyl Cryptognaths. One of these appears to be very basal on the family tree, possibly splitting off before even the Chalacheiroptera split off. Not much is known about these creatures besides some footage few trail cameras.

Bottom row, middle right: The second line of rodent like Effingodactyls actually resemble hyraxes or small notoungultes more than rodents. Being small hoofed critters that feed almost exclusively on plant matter. They are distantly related to other hoofed Effingodactyls and it remains a bit unclear whether or not this group is monophyletic.

Bottom row, right: The final identified group of rodent like creatures are the Skalisorhynchids, a clade of Eusymmetrodactyl Cryptognaths whose affinities remain unclear, but are obviously part of the "Polyotoalosia". They have a combination of very derived and quite primitive traits among Eusymmetrodactyls, so where and when they came from is a mystery, but by the present they are very successful and widespread, only being surpassed by the Triprotodontid, which often seem to drive them to niches they wouldn’t normally occupy or straight up outcompete them.

Clade Profile: Pectinauts

Eryobis was once a world with an ocean ruled exclusively by fish. Many types of coelacanths and holosteans dominated every imaginable marine ecosystem and seemingly nothing could ever dethrone them

That was…, until Eryobis was hit by an object from outer space that carried such incredible energy that the entire first 200-500 meters of ocean around the globe were evaporated and so killing every fish in it.

A few fish did survive in deep water and isolated freshwater habitats furthest away from the impact, but they would never recover from the extinction.
So, now there was an ocean devoid of larger animals in the photic zone, niches free for the taking.
Several groups took to the occasion:
* The conodonts like Nienktvissen and Squidn’ts whose ancestors had survived in the deep sea.
* The Llamplelganae polychaetes which took it upon themselves to fill the most of the niches we typically associate with cephalopods.
* And then the subjects of todays post: the Pectinauts

Pectinauts are bivalves in the order Pectinida, commonly known as scallops. On Earth, scallops are capable of swimming by taking in water and then pushing it out of openings next to the hinge of the shell, giving them a weak jet propulsion system.
On Eryobis, they took this a bit further following the extinction of nearly all fish. In the beginning they were clumsy swimmers as scallops are on Earth, but pretty soon they figured out a way to do it more efficiently. They oriented themselves upright. A large improvement compared to the ancestral laying on the side condition. Accompanying this new orientation, they also modified their foot into a rudder to help them steer, though it would come to be used as a tail in many future forms.
Scallops on Earth can have up to 200 eyes. These tiny eyes are typically located on the edge of the mantle close to the shell and can be retracted for protection. Early Pectinauts also had such eyes, but these eyes were adapted for a life of lying sideways on the seafloor, not for swimming upright in open water. So the Pectinauts had a problem: they could not see what was to their sides or behind them.
For this issue, they came up with a most curious solution. Early in their lifecycle, a dent forms on each valve. As they mature, these dents form slits and within these slits are a number of eyes, which are also typically the largest. This results in Pectinauts having cloven shell valves, a unique appearance and an easy way to tell them apart from other bivalves.

Most Pectinauts can be classified in one of two main groups: frontswimmers or backswimmers. As the names suggest, the main distinction between the groups is whether the mantle is facing to the front or the back when swimming.
Frontswimmers (1-6) are usually considered to be the more basal of the two groups. Some are thought to still closely resemble the ancestral Pectinauts and most of them live in shallower waters and reefs where they feed mostly on algae and plankton. Many of them have modified their tentacles into large appendages for a variety of purposes such as catching food, luring prey and in some cases even as fins.

Backswimmers (10-15) differ from frontswimmers in that they swim with the hinge of their shell moving forwards. Their mantle and tentacles are thus facing backwards while they swim, sort of like cephalopods. In general, backswimmers are quite derived. They occur in many shapes and sizes and occupy a greater variety of niches than frontswimmers do. Their tentacles tend to be thicker, their digestive systems more extensive and their propulsion system more advanced. While smaller and more basal forms often feed on plankton, the larger and more advanced forms tend to feed on algae, corals, crustaceans and in case of the large free swimming forms even other Pectinauts, Llamplelgans and even fish. Some backswimmers have taken on forms that resemble fish quite closely. They turned their feet into large tails and swim by combining this foot motion and jet propulsion.

Then there are a number of outliers among Pectinauts (7-9). Such forms cannot be classified as frontswimmers or backswimmers for their mantles and valve hinges are not facing the direction they’re swimming. Many of these forms love in the deep sea suspended and largely without much motion, patiently waiting to for food to wander into their tentacles. Other forms of these outliers live in shallower waters where they sift through the sediment for smaller molluscs, crustaceans and annelids which they then kill with modified tentacles that sport spikes. It’s generally believed that these outliers are an unnatural grouping that split off from both frontswimmers and backswimmers at various points in their evolution history, but much research is still needed to understand the full picture of the Pectinauts.
 

Lantern Leviathan

“…huh what’s that?”
“Holy f*ck”
“Oh my god”
“Would you look at that… holy…”
- radio recording of divers in submersible [REDACTED]

Their reactions are understandable. It’s not every day when you’re deep in the open ocean in a tiny submersible that you accidentally stumble upon a, as of yet, undiscovered titan of a fish. Luckily for them, this is a gentle giant that feeds exclusively on zooplankton and other small free swimming animals.

With its fins spanning over 10 meters in length and weighing multiple metric tons, this is by far the largest Nienktvis alive, one of the biggest marine animals on Eryobis and possibly the most massive conodont that has ever lived.

While nowadays these leviathans live in the upper water column, peacefully filtering food with their gills, their bioluminescent organs reveal that their ancestors did share this pacifism.
Typically speaking, the only other nienktvissen with bioluminescent organs are bathypelagic predators. Using bulbs on the ends of their whiskers to attract prey and glowing teeth/ gums to guide food to the mouth.
While it seems the giants have kept this strategy, they now use it for a less bloody purpose than their demon toothed deep sea cousins.

Opal-eyed Squidn't

"...When we first set sail to collect and catalog marine fauna in the seas of Eryobis, we had no idea what to expect. After many days of catching, analyzing and observing, we captured many species of fish, crustaceans and even some marine insects, but we were surprised to find that there were no cephalopods among our catches. Which was... weird, actually.
Genetics gave revealed that most species on Eryobis diverged from their Terran relatives somewhere in the early Jurassic and we know for a fact that there were cephalopods swimming around in that time."

"On the last day of our expedition, just as dusk began to fall and we were about to leave, I saw something in the deep. The silhouettes of conical shaped creatures with two big fins on one end and multiple appendages on the other. Could this be? A squid at last? And even though they appeared to be swimming in the wrong direction, I figured anything was possible keeping in mind what other strange animals live here."

"As by law, anything we saw, we had to collect and catalog, no matter what the cost. But the squids kept their distance while there was still light. So we figured that like with squids on Earth and other colonies, we had the best chance of catching one after dark. We set out our traps and nets, as diving in the dark was a little too scary for us, and waited for one to take the bait..."

"Several hours must have gone by, as it was only after midnight that we finally got one. Instantly awakened from our naps, we started pulling up the net as quickly as possible. It went surprisingly easy, the animal wasn't struggling at all. Full of excitement, we pointed all our lights at the net as it was pulled out of the water. But inside, well, was no squid. It remained still, until the moment a flashlight met its eye. Then all of the sudden the creature started thrashing around and with its razor-sharp teeth, it cut through the net and fell on the deck. Here it began thrashing its body even more violently. As one of our team members tried to subdue it, with a single sideways motion, the creature chopped of his right hand and slit his throat with its teeth.
Blood flowed everywhere, covering the entirety of the deck and as the creature was still jumping around... we had no choice but to kill it. After multiple missed shots, we finally managed to stab it in the eye with a harpoon. As our team member had bled out, his hand separated on the floor, we got the chance to take a better look at this monster."

"It had a smooth skin, no scales at all, yet it was surprisingly thick and leathery. Seven gill slits lined up behind its large eyes. It has two large fins at the back of its body with several finlets in front and behind it.
Lining its mouth were ten whisker-like appendages and then finally, the mouth itself. It was absolutely horrifying to look at. Four huge tooth-plates lined the edge of the mouth, all of them independently movable from one another. Looking inside the mouth was like staring into hell. Many tooth-plates were located in the mouth, several rows of teeth of different shapes and sizes lined its maw like gears in a machine. All were rotatable, most were extendable."

"Later research would point this creature out as a Conodont, a kind of jawless "fish" that went extinct in the late Triassic. So as of yet, no squid have been found on Eryobis..."

Clade Profile: Llamplelganae

Beneath the waves of Eryobis we can find a group of very strange looking animals, even for Eryobian standards. Occurring in habitats ranging from the shallowest reefs to the deepest ocean canyons, they have conquered every marine habitat and some even venture into freshwater.

But what are these odd creatures?

The locals (Hrennat language) call them llamplelgans, roughly translating to “fluttering fish snail”. But they are no fish, nor are they mollusks. Instead, they are glyceriform phyllodocidan polychaete annelids, or simply put: Eryobian bloodworms.

They left their wormy appearance far behind them however, nowadays looking more like if a cuttlefish had a baby with a scorpion and had it raised by crabs.
Their annelid ancestry becomes more clear when you look at how they develop. They start out looking like a more typical polychaete worm, but fold their posterior bodies ventrally as they mature. What you end up with is a worm folded up like a taco with chaetae for fins on both sides being able to swim in every direction available to a 3-dimensional animal.

As they evolved to be far larger than most annelids, they had more need for the ability to see their surroundings. Deriving from the primitive compound eyes of their ancestors, llamplelgans evolved 2 pairs of highly advanced compound eyes on par with those of mantises. Their ommatidia in the anterior eyes are slightly more forwards directed while those in the posterior eye are directed more sideways and backwards, giving them an almost 360 degree field of vision. This causes their pseudopupils to seem unaligned.

They evolved eight long tentacles on either side of their heads which aid in detection and manipulation of food and often hunting. But their main weapon is their retractable proboscis edged with large copper coated teeth. Not only are these teeth strengthened with copper, they can also inject a deadly venom into whatever is unfortunate enough to get caught. Llamplelgans deploy this weapon by extending their esophagus and turning it inside out to reveal the teeth. Whatever gets impaled by the teeth will then just get pulled into the llamplelgans esophagus and will never see the light of day again.

This species depicted here is Llamplelgania peregrina, a medium sized species that mostly inhabits the tropical coastal waters of eastern Guralta. In the picture it is about to attack an unlucky ray / flounder-like nienktvis. A soft bodied animal, the nienktvis will get swallowed by the llamplelgan without much effort.