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.