Ifrit and Tynus

The Ifrit on top and the Tynus at the bottom are both members of the phylum Onychognatha. Onychognaths are the arezoans which in morphology come closest to Earth’s vertebrates, as they are bilaterally symmetric and possess an endoskeleton and spine of apatitic (though sometimes also siliceous) make-up. Though this is usually as far as similarities go, as many of the body forms these animals assume have more of a resemblance to arthropods and in their very bony heads there is little room for much of a brain. Phylogenetic bracketing indicates that the ancestor of this clade likely was a worm-like animal with a bony tail and ten or even more limbs (two pairs pre-oral, three pairs post-oral), each attached to their own segment and with hands with two fingers. From this basic body plan all further morphologies were achieved through thagmosis, the fusion of segments. In almost all living onychognaths, the eye-segment fused together with the two pre-oral segments to form a solid cephalon, with the pre-oral legs becoming sensory antennae. Also, in almost all living forms, the first post-oral limb pair fused with the back of the skull to form mandible-like jaws, with the two fingers on each hand becoming arachnid-like cheliceres. In the majority of forms, the remaining six legs are used for walking, in a rather insect-like manner.

A good example of this is the diminutive Tynus, just 20 centimetres long, which can be best described as a cockroach-lizard. It is therefore also sometimes called the “Marsroach” (the alternative name combination “Cockars”, suggested by a particular member of the expedition has not won out, for obvious reasons). During the day it is mostly found underground to escape the desert heat, during the night it comes out to hunt smaller relatives and dust slugs. With its first pair of antennae it mostly smells, with its second pair it mostly hears. The breathing system of onychognaths is decoupled from the head, instead there are six breathing orifices, one in front of each leg, which lead to their own lung sack, somewhat similar to the booklungs of arachnids. In most onychognaths like the Tynus, the four sacks at the front specialize in oxygenic respiration, while the hindmost pair has a more elaborate structure to create better anoxic conditions for methanogenic respiration, hence the elongated section behind the hindlegs. Once morning arrives, the Tynus usually laps up dew from smooth surfaces or even licks it off its own eye with its tongue. The eyes of all onychognaths are solid lenses made of biosilicon. This has both advantages and disadvantages in the harsh Martian environment. On the one hand, with solid eyes, there is no need to shield them from dust and sand blowing with the wind, as there is no liquid surface which could clot up the particles. On the other hand, the recurrent abrasion by sandy winds does over time create scratches on the eyes, which can impair the vision of the animal if they start accumulating. Many onychognaths therefore have to shed their eyes and regrow them once they wear out. Usually, the eyes fall out asymmetrically timed, so the animal does not go completely blind during the regrowth phases.

Generally, two grades are distinguished within the phylum: the paraphyletic Archaeocephalia, which possess the ancestral chelicerous jaw apparatus and of which the Tynus is a part, and the monophyletic Cuneocephali, which likely derived from the former. In Cuneocephali, such as the Ifrit, the arm-bones holding the cheliceres have fused firmly to the cephalon and the bottom fingers have become an immobile lower jaw, also firmly fused to the rest of the skull. The sole moveable part are instead the upper fingers, which have fused into a singular beak which opens and closes sort of like a toilet seat. Why these bizarre “wedge-heads” evolved is hard to say, though the rigid design has in some species allowed for the attachment of surprisingly strong adductor-muscles for the upper jaw. Cuneocephali usually also have a more complex circulatory system than their forebearers. The individual lung sacks are interconnected, with the job of exhaling and inhaling being split up between the orifices and the oxygenic sections providing the methanogenic ones with carbon dioxide.

The Ifrit is a predator of smaller desert creatures like the Tynus. It usually kills them with well-placed, paralyzing bites to sections of the spine. Its actual method of eating is rather baroque, sometimes thrashing the carcass around or even performing deathrolls in order to rip out pieces of flesh. What is fascinating about the Ifrit is that it seems to be in an apparent phase of evolutionary transition. Cuneocephali descend from hexapods not unlike the Tynus. In the Ifrit however, the last pair of legs looks like it is in the process of vanishing, as they have shrunk and are dragged through the sand rather uselessly. But they are not completely vestigial, yet. Like all Martian animals, the Ifrit is hermaphroditic and once the time to mate comes, the two partners engage in rather daft wrestling fights to determine which loser gets to be impregnated. The small legs are used in these fights to help keep the opponent’s hindquarters down on the ground.