Dedrorax and Zyloron

 
A peculiar difference between Earth and Mars is the ways in which the local fauna has chosen the number of limbs on which to walk. On both planets there are plenty of bipeds, hexapods as well as creatures with no limbs at all. Outside of that, on Earth, animals have eight or four legs, whereas on Mars, tripods have evolved on at least two separate occasions while tetrapods are only secondarily derived from hexapods. What leads to such a difference? A popular explanation might be the differences in gravity, the heavier creatures of Earth requiring more legs for support, but so far nobody has been able to prove a direct causation. If it were true, it seems odd that the animals with the most legs on Earth are also all among the smallest and thus least affected by gravity, while hexapods are also abundant on Mars. Evolutionary history and contingency seems to be an equally strong factor, if not stronger. Periostraca ancestrally had only two limbs and so were restricted to bipedality unless also turning their tail into another limb, making tripodality their evolutionary “end-point”. However, the same restrictions would not have applied to the onychognaths, yet when natural selection called for the reduction of their limbs, they jumped straight from six to three with almost no transitional forms, which suggests there might really be an adaptive advantage to tripodality in the Martian environment.

A world apart from all of these discussions is an animal with no equal on Mars, let alone Earth. The dedrorax is a genuine monopod, at least when it has to be. When slow and idle it slithers across the desert, using its boomerang-shaped headshield to glide above the sand, but when in pursuit of prey or fleeing from predators it erects itself onto its muscular, bony tail, which ends in a three-toed foot, and hops away in wide strides like a kangaroo. When attacking its prey, it will extend a snorkel from beneath its headshield and strike out with a beak. From its back extends a retractable sail held up by bony rods. Perhaps it used in temperature control or social signalling.

Dedrorax are rarely observed and thus little is known about them, including their overall behaviour and reproduction. For a long time it was even unknown to what family tree it even belonged, as it seems to combine traits of many lineages, sort of like a Martian platypus. It has simple been considered incertae sedis. Close comparison to some other strange creatures offers at least some clues. The dedrorax has a partly siliceous endoskeleton and spine-like protrusions supporting its eyestalks, as well as a triradial cloaca in front of its sail. The beak at the end of the proboscis is three-pronged. These are all traits it shares with arezoans such as the arctic sortax. This points towards it being a highly derived member of the Furchordata, perhaps even the most derived trichordate of all time. How exactly this led to its evolution as a monopod is, however, not clear. Perhaps its ancestors were able to erect themselves and strike out on their tails like cobras and some unknown selective force reinforced that ability?

Among the reported prey of the dedrorax is the zyloron, a member of the verticutian dust slugs. It and its close relatives have lost their ancestral pseudopods and instead move much like serpents. They themselves predate on smaller onychognaths. Their armour has been reduced, something they compensate for with speed and being able to quickly bury in the sand.

The Great Orm of Mars

Fig. 1: An alleged photo of a sandworm briefly surfacing, captured by the Curiosity rover. In reality it is a rock formation of crystals whose surrounding matrix has eroded away.

 

The majority of life on Mars is tiny to microscopic in size. The number of lifeforms than can grow taller than a human can be counted on one hand. Any megafauna has been extinct for millennia, if not for millions or even billions of years. Or has it?

Rumours abound of the great dustbowl desert of the northern hemisphere being home to a gigantic creature that swims through the sands like a whale through water. These rumours of “sandworms” are largely based on grainy satellite imagery, geological structures claimed to be “worm-signs”, including the infamous canals, and some eyewitness-reports made by space tourists. At least one Mongolian cosmonaut claims to have seen one as well, likening it to the “olgoi-khorkoi” of his homeland. Professional spacefarers of western countries have meanwhile never made such claims (though even if they did see one, they might not report it out of fear of being seen as unprofessional, as often happens with UFOs). Nobody has ever been able to produce any physical evidence or even clear photographs of the creature.

There are various reasons that speak against the creature’s biological reality. For one, it seems physically impossible for an organism to move through sand as if it were water, especially at the claimed great speeds. Sand simply does not work that way and even if it did, the friction would create an unimaginable amount of abrasion and heat that would likely damage most organisms. At least one cryptoxenologist, Roy Sanderson, has countered this by claiming that the worm might be able to create vibrations in the ground that turn sand into a non-newtonian fluid that makes it easier to swim through. If this really were the case though, seismometers at various Martian research stations would have surely picked up evidence of such vibrations.

Even ignoring that, there is the question of how an organism this big would even be able to subsist in a biome with so little plant and animal life. Some cryptoxenologists have argued that in the deep underground of Mars there might be hidden lush ecosystems that the worms might be feeding on, like sperm-whales diving into the abyss to catch squids before surfacing. There is no evidence for these hidden ecosystems, so this is just special pleading. A more sensible suggestion that has been made is that the sandworms might be lithotrophs, literally feeding on the iron dust they plough through, because we actually know these types of organisms exist on Mars. This has led to some fanciful speculations that the worms might be giant offshoots of the otherwise small dust slugs. The problem is that the iron-reducing lithotrophy of the dust slugs is an inefficient energy-source that seems very unlikely to be capable of supporting any larger animal. Though we do not know how this system changes if an organism with a larger gut is able to ingest far greater amounts at a faster rate. Similarly to hindgut-fermentation in sauropod dinosaurs, larger body sizes might actually make digestion far more efficient than in smaller animals. But this is just speculation with no direct evidence.

Lastly, even if it is on another planet, it seems highly unlikely that an organism this large would go undetected for so long. Even if they lived 99% of their lives underground, the movements these creatures would create would, as mentioned, surely be detectable by seismometers.

Fig. 2: Satellite imagery claimed by Holland to show a giant worm or wormsign.

But if these sandworms are mere myths, then why do people keep claiming to have seen them? Perhaps the very first claims of giant sandworms on Mars, certainly the first ones to be widely published, were made by one William T. Holland in December 1978, based on grainy satellite imagery he claimed to show the worms and traces left behind by them. The images in reality just showed dune-filled canyons, which appeared convex instead of concave due to lighting. However, the date of Holland’s claims is highly intriguing, as they were made just a few months after the release of part 1 of Alejandro Jodorowsky’s epic Dune quadrilogy. Just like the novel they were based on, the movies prominently displayed the fictional giant sandworms of Arrakis, brought to life thanks to H.R. Giger’s amazing designs and Phil Tippet’s ground-breaking go-motion technology. It seems very likely that Holland’s interpretation of the images were coloured by the movies and their popularity among general audiences further boosted the perceived plausibility of the cryptid. Many of the space-tourists who claimed that the unusual sand dunes they saw crawl across the desert were the legendary worms admitted to having read Holland’s books on the matter, so their interpretation was thus indirectly also coloured by Jodorowsky’s Dune. Therefore, they all saw giant sandworms on Mars because they wanted to see them.

Tachmut and Skrael

 

What is an inhospitable landscape to some may sometimes be comfortable to others, if they have the right adaptations. One of the most common critters throughout the Martian tundras is the tachmut, a type of lobostomian spirifer. Bodywise, this limbless space slug shows little difference from its relatives, except for a thin fringe of hair-like setae growing below the rim of the dorsal plates (the function of which is unknown). What sets it apart is instead its surreal grin. Atypically for most lobostomians, the arms of the tachmut are internally supported by rigid cartilaginous rods and have robust, molar-like teeth growing out of them, in structure similar to the teeth found in their verticutian cousins. The purpose of these is obvious. The main diet of the tachmut are the red filulithophores which carpet the whole tundra during summer. These are macroareonts, prokaryotic organisms that function like a mix of diatoms and dictyostelids. Almost all their above-ground organs, such as the stalk and the fruiting bodies, are protected by a chainmail of phytoliths, little armour plates made of silicon dioxide. Though this biosilicon shell is thin, it can cause heavy abrasion if consumed too much, which is why toothless herbivores like onychognaths largely avoid eating them. The tachmut can meanwhile fully exploit this food source, using its toothed corona just like how a horse’s jaw grinds down grass. Unlike a grazing mammal, the tachmut can continually replace its teeth once worn down. Once grinded into a pulp, the vegetation’s remains are whisked into the mouth using the characteristic setae.

Being the main consumer of this vegetation, the tachmut is a vital keystone of the tundra’s ecosystem. Filulithophores are major nitrogen fixers, but because few feed on them, the tachmut liberate this vital element and accumulate it in their bodies. Thus, the tachmut becomes an important source of nitrogen for all the predators and omnivores that feed on it. Perhaps more importantly, the gut of this space slug dissolves the ground up phytoliths into silicic acid. The nephridia (its equivalent of kidneys) then draw most water out of this substance, turning it into silica gel (which is why at least one Japanese desiccant company has made this alien their mascot), which is excreted out at the back with the other waste. This gel then dissolves in the wet soil of the boggy summer tundra, allowing filulithophores and various other flora and fauna to reuse the silicon dioxide for their skeletons.

Tachmut are classic r-type strategists when it comes to reproduction. Usually, when two individuals mate, both partners have their eggs fertilized. Like snails, they then lay these into wet burrows during the warmer summer months and slither away. Once the long winters signal their arrival, tachmut bury into the active layer of the permafrost while it is still malleable. Once settled, the organism enters a deep state of dormancy during which it is nearly dead and most of its body fluids are infused with a biologically produced anti-freeze, not unlike the red fronds it shares its environment with.

Some, however, make this season easier for themselves by exploiting their neighbours. Instead of digging their own, tachmut may simply crawl into abandoned burrows left behind by skrael. These are caecilian-like archaeocephalians. During the summer, these serpentine organisms build rather peculiar nests. First, they begin digging tunnels into the thawed topsoil of the permafrost, using their spade-like cranium, which has modified the head so much that the antennae grow from underneath the head. Then they actively suck up and spit out the excess water until the burrow is dry. To prevent the ground water from seeping in again, the nest is then plastered with a coat of sticky saliva that, like in some birds on Earth, quickly solidifies into a waterproof and isolating coating. The home is then further stuffed with fragments of sporian skin and the shed filaments of fuzzy animals that roam the tundra during the summer. From this cozy nest the skrael then lives a largely stationary life, using its antennae and skull to pick up the vibrations of any smaller critters crawling nearby its hole to snatch up the unsuspecting prey. The skrael’s eggs and young are also raised in these nests by the caring parent. During winter, the animals curl up into a ball and sleep, though at the same time they raise their metabolism, utilizing their body-warmth and the nest’s insulation to keep the interior above freezing.

Although the two animals usually do not seem to get along, an amusing observation that has been made by some researchers of the Martian tundra is that tachmut and skrael may sometimes be found enduring winter in the same hole. This likely does not happen out of friendship but out of desperation and/or apathy. The tachmut is desperate to find a winter home, while the skrael is too sleepy to be bothered by or even notice its new roommate. That said, it has been theorized that skrael may occasionally exploit this cohabitation by feeding on the dormant tachmut, should their own winter reserves run out.

Malacoda

The Malacoda is an organism commonly found in the deserts and desert edges of Mars. It can perhaps be best described as a hand-sized land-clam. Unlike in a clam, its shell has no hinge, instead it is a single piece with five openings. The posterior or "bottom" opening is where a muscular foot emerges, which the organism uses for locomotion. It is a stiff trunk, possibly supported by internal fibres of cartilage or other materials, clad in scaly skin and terminating in three snake-like tentacles. Malacoda cannot walk or jump, instead they slither across the sands at a leisurely pace. The foot is also the main organ used to dig themselves into the ground.

Along the ventral or "front" side are three further openings. From these emerge stalks with remarkably complex lens eyes at their end, quite similar to those of conch snails in appearance. These may have evolved from ocelli that lined the mantle rim of the animal’s ancestors before the shell fused nearly shut. Each of these eye-orifices has a little valve, so the stalks can retract into the shell and be closed off from the world when the malacoda senses danger from predators or sandstorms or needs to bury itself.

At the anterior end or "the top", is the opening for the retractable proboscis. At its end is a robust, somewhat bird-like beak of still unknown material, remarkably similar to what is found in the Periostraca, though this likely is a case of convergent evolution. Underneath the mouth are also two slit-like orifices, likely breathing holes leading to simple lungs, which may be comparable to the apical opening of a scaphopod or the siphon of bivalves. Amusingly, if a malacoda is viewed from behind, the two orifices may look like two eerie eyes, giving the back of the proboscis the appearance of a mouthless, vaguely humanoid face. When the proboscis is fully retracted into the shell, only the beak may peek out. The shell is notable for its narrowness and spines. The spines are rather blunt, so they likely serve less a protective purpose and are more useful for when the animal buries itself vertically down, much as in digging clams.

Malacoda spend the majority of their life buried underground, often in a dormant state. Once the long Martian autumn approaches, the snakeish tentacles vibrate and bury the foot into the ground. Through periscoping motions the rest of the trunk is then buried and through rather adorable wiggles the shell drills itself into the sand until only the proboscis may peek out of the ground. Often, however, the malacoda is buried so deep that only a small funnel in the ground hints at its presence, at whose end the open beak may lie in wait like an antlion in case any small critters accidentally slide down the hole. Once finally the winter comes, even this wait ends and the organism enters full anoxic dormancy, in which its metabolic rate becomes so low that it might as well be dead. Finally in spring, the malacoda emerge en masse from their graves to feed with their robust beaks on the short bloom of succulent desert flora, often in the form of monovexillan fronds or spongisporians. During this time they also reproduce by impregnating each other through the mouth. Their eggs are laid down into the wet sands near oases or ephemeral ponds, where they have to lie dormant for at least one winter before being able to hatch into miniature versions of the adults. Often though, the eggs may lie dormant for decades until hatching.

Malacoda are Martians of intriguing affinity. The construction of the proboscis is reminiscent of some of the Antitremata, whereas the presence of a muscular foot attached to the mantle is a feature associated more with the Spiriferia. The construction of the shell is comparable with neither. The Martian fossil record suggests that the malacoda is the sole surviving member of a whole phylum that has otherwise gone extinct, the Conchocauda. Likely related to the aforementioned clades, these were a group of marine and freshwater armoured animals, whose fossil shell superficially resembled that of clams, but entirely lacked a hinge, meaning it was a single, inarticulatable piece, often with a narrow slit at the “front”. In the malacoda this slit seems to have fused, leaving only the aforementioned openings. As far as can be judged by soft tissue imprints, the extinct Conchocauda lacked eye stalks and a beaked proboscis, meaning that these are novelties evolved by the malacoda, likely as an adaptation towards life on land and a change in diet. Conchocauda were dominant reef builders during the early Thermozoic Era, but seem to have gradually declined ever since, likely as a result of the planet drying up (Sivgin 2345). Unlike Antitremata and Spiriferia, they seem to have made the jump to land only very late in the planet’s history, leaving most of them to die with the oceans, while the few latecomers to land were easy prey for far older lineages. Nonetheless, the malacoda’s life strategy seems to be working out, as its population numbers are comparatively high and the animal is widespread across the warmer regions of the planet. It is the last of its kind but also the most successful.

An interesting oddity discovered during autopsy by a team of the astrobiological department of the CNSA is that the saliva inside the malacoda’s beak contains a mild toxin of unknown purpose. There are no known cases of (living) malacoda biting astronauts and the toxin is far from lethal, but if it were to be ingested, it could cause mild hallucinogenic effects similar to LSD. While perplexing, this seems oddly appropriate for such a bizarre-looking organism. Possibly it affects Martian natives differently due to their biochemistry, so this could be a protective weapon against predators.

On that note, it is also probably impossible to not mention that this same study was also the cause for possibly one of the most spectacular and darkly amusing mishaps in the study of Martian life. Although the specimen being studied was already dead, the researchers must have accidentally poked its nervous system in such a way that the proboscis reflexively shot out of the shell and mechanically bit one of the biologists right in the crotch area. The victim, who in most accounts is referred to by the pseudonym “Boning McGee”, had their penis cleanly bitten off. Though the organ was later able to be reattached, the released study bizarrely included the rather mean and inappropriate remark that it would not have been much of a loss (Manchot 2334). This likely hints at quite a bit of behind-the-scenes animosity among the workers of the CNSA.

References:

• Manchot, Hans: General description of new genus and species Xenocadulus bethanyensis, including phylogenetic speculation and possibility of medicinal use, in: Astrobiology Magazine, 679, 2334, p. 211 – 222.
• Sivgin, T.K.: Life on a Dead Planet. The first 3 billion years of Evolution on Mars, Zürich 2345.