Arctic Sortax

 

Peering beneath the ice caps and glaciers of the north pole of Mars can reveal an assortment of many strange creatures. One of them is the sortax, a flattened, cushiony creature with a strangely bifurcated spine out of which grow a tadpole-like tail and two eyestalks. A common urban legend on Earth regarding this animal is that when an astrobiologist, usually only named “Dr. Morris”, if named at all, first discovered this creature, while livestreaming his expedition as a public NASA broadcast, he shouted “Fuck, another new phylum!”. The resulting PR debacle then led to him being fired in most versions of the story. This is almost assuredly a pop cultural myth that is entirely fabricated. The true discoverer of the sortax was a woman by the name Eryx Burton, and there is no comparable recording in any of NASA’s archives (for how the myth may have formed, see Busch 2338).

More importantly, Burton never made the claim that the sortax belongs to a separate phylum, as examination quickly uncovered its ties in the Martian tree of life. The animal’s endoskeleton is made of apatite and silicon dioxide and the anatomy of the tail is identical to the arms of trichordates such as the hortax. The tri-radial cloaca on top of the body is also another dead ringer. It strongly suggests that the sortax is a trichordate, but has shifted away from the ancestral radial symmetry of its star-fish-like ancestors towards a bilateral one. Two arms stiffened and became structural supports for an expanded gut and mantle, their tips becoming mainly sensory organs, while the third became a tail. The three-pronged mouth shifted from the bottom of the body towards the front. This is certainly not as extraordinary as it may seem, as on Earth many radial animal groups also have members with bilateral elements, such as ctenophores with two tentacles, or sand dollars and irregular sea urchins among the echinoderms. Like in the latter example, the anatomy of the sortax and its relatives may have originally arisen as an adaptation towards horizontal digging in marine sediments, where a radial body is less beneficial than an axial, streamlined one.

Though it is primitive in its aquatic habitat, the sortax likely does not represent this ancestral state, as it largely lives on top of the sediment and only digs itself into the sand when danger, such as arctic rhosons, presents itself. When on the search for food, the sortax moves by hovering through slight, carpet-like undulations of its flabby mantle, the tail only being used when quick bursts are required. Its main prey include the various worm-like organisms that inhabit the subglacial silt: circulates, pseudarticulates and mollizoans. These are usually devoured through suction feeding, whereby the prongs of the mouth open fast enough to create a brief vacuum. Swallowed whole like spaghetti, the prey is further processed by a masticating stomach.

It is interesting to note that the eyestalks retain some form of independence, similar though not to the same degree as the arms of more classic trichordates. While looking for prey, usually one eye faces forward to focus, while another one surveys the area. Unlike the arms of the hortax, these do not alternate in their tasks but seem dedicated to their roles, though with variation between individuals. In other words, some sortax are right-“handed”, while others are left-“handed”. It would be interesting to further study if the rest of the nervous system has also retained a degree of decentralization or has instead undergone more streamlining during bilateralisation.

Since its discovery, it has been recognized that many strange problematica found across Mars are likely relatives of the sortax, something substantiated by recent molecular analyses (Schaf 2337). This likely monophyletic clade has been named Furchordata and is now largely recognized as a distinctive class among the Trichordata. Trichordates, due to the shape of their cloaca, leave behind peculiar trilateral excrements, which in Furchordata specifically get twisted into strange spires due to their more complex guts. Coprolites of exactly this shape have been found in Middle Athabascan sediments, indicating that furchordates first emerged shortly after the End-Cydonian mass extinction event (Brot 2339).

References:

• Busch, Briegel: Marsgeschichten und andere tolle Sachen, Berlin 2338.
• Brot, Bernd: Mist. Die Ultimative Enzyklopädie, Beck 2339.
• Schaf, Tchili: Testing the Furchordata hypothesis using sequenced Martian genome data, in: Current Astrobiology, 465, 2337, p. 13 – 23.