Irsu

“And I will send the beast of the field among you, which shall rob you of your children, destroy your cattle and make you few in number; and your ways shall become desolate.”

-Leviticus 26:22

The Hellas Basin could be called the “most functioning” ecosystem on Mars, in that its vegetation cover allows for more or less fleshed out trophic levels at all heights. Unfortunately for everyone involved, that includes active predators. Of these, the Irsu is the most ferocious, the most deadly, non-venomous animal so far discovered on the planet. Its jaw alone is the largest among any Martian, its hardened, self-sharpening tooth-plates reaching up to the length and height of butchering knifes, able to bite through bone like butter.

This is a survivor of a past age, one where pedicambulates ruled the planet. And it does its best to not let that memory die. It alone rules over these desolate plains, always stalking through and ambushing from the fronds and spongine growths with great efficiency, its spotted pattern presumably helping it camouflage. It lays waste to both onychognath prey, whose chest-lungs it loves to tear open, and others of its own clade, whose internal shells its teeth cut through with ease. Other predators, such as sutekh hounds or the heremakhet, fear it and rarely fight over carcasses with it. Living solitarily, Irsu are not even safe amongst themselves outside of breeding season. In a stark contrast, they make for decent parents. Usually only laying one large egg, the chick is cared for greatly by its single parent until it is old enough to hunt by itself.

Among the favourite prey of Irsu are the great ushabtis and their relatives, their glass skeletons being easily broken by its teeth. These dumb animals being, by coincidence, quite humanoid, has led to some obvious and quite perilous problems for human space explorers. The Soviets were the first to explore the great basin and, infamously, these first cosmonaut pioneers were not given guns, as they did not initially expect this kind of life to be found here (at least this was the official explanation, some rumours state that they were not issued weaponry for budgetary reasons or due to fear of suicide or homicide within the team). Alas, all that his friends could find of poor Yuri was vomited-out flesh and one of his boots, his foot still inside. Being of a different biochemistry, the alien was presumably unable to completely digest the man. Though this still leaves the question open where the rest of his spacesuit (and skeleton) went. There is an urban legend among astronauts that parts of Yuri can still be found strewn across Mars. A glove there, a helmet-piece here, maybe a knucklebone somewhere right by the Great Face. Indeed, there are now rumours that the Chinese recently found a heavily corroded human mandible… at the opposite end of the basin from where he died. If true, either some scavenger has carried this bone very far or there are more casualties the other space agencies do not want to tell us about.

Back on Earth, the Irsu has become a popular choice for plush-toys. My grandson owns one, he calls him Ogilvy, after me.

Nerak Thunderbolts

Nerak thunderbolts (Moranis dominans) – named “Neraks Donnerkeile” in the original German – are peculiar invertebrate Martians first encountered by ESA missions in the Kasei valleys. Their name is in reference to their superficial resemblance to belemnite guards, which in medieval folklore were believed to have been petrified lightning strikes. They also go by the name of “helmetworms”.  

Originally believed to be characteristic of the sloped and canyoned terrains of Tharsis, multiple species of neraks have since been found all across the northern hemisphere of Mars, sticking out of most mesas, buttes and rock outcrops. They are arezoans which consist of two calcium carbonate shells that, together, resemble a rifle bullet or artillery shell. Inside the shell is a tentacled organism with a water skeleton. To open the top, the organism hydraulically stiffens a rod in the body’s centre, which makes the mantle grow not unlike a human erection. To close the shell slowly, it simply deflates, though it can also be closed through muscular action if it needs to be done quickly. The skin of the mantle is scaly like in a snake. The nervous system is simple and brainless, sense organs largely consist of chemoreceptors and statocysts that measure air-pressure changes.

Even more so than the dust slugs, neraks are characterized as mineral-eaters, directly feeding off the rocks they grow on. Usually hidden from view, the bottom of the main shell has an opening for an extendable leech-like “mouth”, which gnaws and licks at the rock, dissolving it with acids and scraping actions from a radula. Inside their guts live various areonts which generate energy through lithotrophy, breaking apart the consumed minerals. Different nerak species can have different types of endosymbiont, allowing them to digest different kinds of rocks. Some oxidize iron, others nitrogen compounds and again others might both oxidize or reduce sulphuric rocks. Being sessile animals with very low energy needs, these rather inefficient reactions are enough for the neraks to make a living. Neraks have a tremendous role in shaping Mars, their eroding actions creating crumbling cliffs and treacherous crevasses. In some areas, they have turned entire hills into Swiss cheese. This aggressive erosion is surely another major source of the constant dust which dominates the planet. Ecologically they are also of importance, being a water source for shell-cracking predators.

Neraks gain water by opening up in the morning hours to fold out their filamentous tentacles into the air, thereby catching any morning dew. For the rest of the day, they usually remain closed, likely for protection. Interestingly, the base of each tentacle has an orifice which directly connects to the gut. While these holes are likely for the purpose of drinking and waste disposal, it has also been suggested that neraks, much like the aforementioned dust slugs, could be using their arms to filter aeroplankton and/or feed on the constant dust in the air. The observation that neraks remain closed during dust storms would speak against the latter, however.

Using the muscular radula with which they scrape at the rock, neraks also drag themselves forward into the holes they create. Once a nerak has dug in so deep that it cannot extend its tentacles anymore to catch dew, it pushes itself out of its hole and tries to find a new surface to dig into. These moves can sometimes be fatal, the nerak failing to hold on to the rock wall, falling down a steep cliff and shattering at the bottom. Sometimes other aliens and even astronauts can fall victim to "nerak-falls".

Despite being commonly encountered, there are two major questions regarding nerak biology that remain unanswered, which are how they reproduce and how they are related to the rest of Martian life. To this day, no juvenile neraks have ever been encountered, nor any adults in the state of mating, spawning or broadcasting. It is possible that, similar to animals like cicadas, neraks only reproduce in very long, punctuated cycles and we have simply not been on this planet long enough to witness such an event. Alternatively, neraks might be simply mating and spawning deep inside Mars, hidden from our view. Or, similarly to the skolex, one of the numerous worm-like aliens that slither about the planet might actually be the nerak larva, simply having gone unrecognized as such.

After the break-up of the waste-basket-taxon Brachiostoma, helmetworms (scientific name: Rostrozoa) cannot be confidently placed anymore in any of the recognized phyla of Arezoa. The possession of a shell has traditionally placed them somewhere close to the proposed superphylum that contains Spiriferia, Antitremata and Conchocaudata (Egerkrans 2169), but this might of course be only a superficial similarity. The fact that neraks possess more than two gut openings has always been intriguing for those who have studied the Multistomia, a phylum of multi-mouthed arezoans which have gone extinct in the Lyotian or Argyrian period. But the first definitive nerak shells only start appearing in the Late Athabascan, leading to a large gap in the Martian fossil record between them and the last definitive multistomians. More radical is the proposal by Krätschmer 2161, which is that neraks are not arezoans at all, but are instead a distinct offshoot of the aquatic conulareans, a type of shell-building fractarian. The presence of multiple gut-openings as well as a hydroskeleton would speak in favour of this. However, neraks do not seem to possess an internal glide-symmetry.

References:

• Egerkrans, Jakob: Morphological and molecular evidence support the Martian superphylum Areochonchia, in: Astronomical Zoology, 231, 2169, p. 57 – 70.
• Krätschmer, Simon: A fractarian origin for Rostrozoa, in: Strate Station Geological Journal, 511, 2161, p. 90 – 121.