Banuptet

First contact between extraterrestrial life and man-made probes will not always go as hoped, as the Banuptet has demonstrated. Shortly after the Soviet Mars 3 lander descended in 1971 onto Terra Sirenum, its two primitive rovers encountered this duiker-sized critter, the first alien humanity made indirect contact with, as it was apparently grazing on the tundraic vegetation. After cautiously circling the probes, the specimen finally approached them and… attempted to chew on the rovers before losing interest and then defecated in front of the lander. Our guys at NASA at the time allegedly had a hearty laugh upon reading the Russian data.

Despite making such a bad first impression, the Banuptet is nonetheless a fascinating animal. It is an onychognath that spends most of its life nomadically. When it is winter in the south it spends most of the time around the equator and desert oases. Once the spring thaw arrives, it wanders south onto the blooming tundras to feed on the newly growing flora. To efficiently graze in bulk, the Banuptet has evolved a broad rake-like beak to raze off any loose vegetation.

As an endothermic animal, the Banuptet is covered in a unique form of insulation, which could be called “frilled scales”. Likely evolving from lizardine overlapping scales, these have developed frilled, filamentous brims, allowing them to function much more like feathers. Interestingly, the Banuptet cannot be called a true homeotherm, as its body-temperature can vary considerably throughout the year. In active phases of migration or the mating season, its physiology becomes warm-blooded in a mammalian sense, but during the winter-droughts its metabolism slows down and it becomes an ectotherm in order to conserve energy and brumate.  

Banuptets mate towards the end of southern summer. Impregnation between the hermaphrodites is determined by dominance displays using their dewlaps, which can be inflated with blood to turn red. After mating, the “mothers” carry out their young alone while wandering through the tundras and steppes. They give birth to live young, usually two or three at a time. The calves enter life fully developed and able to walk and run. As a consequence, parental care is rudimentary at best; the calves follow their parent for better protection, but the parent itself seems ambivalent as to their existence. As in ruminants on Earth, the young also follow the parent to feed on their droppings, a revolting but vital practice, as otherwise they would not develop the required gut flora to digest the tough plant life on Mars. Most calves do not survive their first autumn migration. 

Fig. 2: The Banuptet's size in comparison with the first man on Mars, Michael Collins.

The Banuptet is part of the wider cuneocephalian clade Deltadactylia, whose most conspicuous trait is that their limb count has been reduced to three: Two hindlegs and at the front a single so-called “great appendage” with four digits, which in some members serves as a third leg, in others as an arm. This is an extreme derivation from the ancestral condition, as even in basal cuneocephalians, the number of limbs was six. How this change happened is a complete mystery. All that is evident is that at some point in their evolution, the deltadactyls must have lost one limb segment, while having fused together the limbs of another. As embryological data is still lacking, we do not even know which of the ancestral segments were lost and fused; the great appendage could have evolved from either the frontmost or middle limb pair. In fact, the missing limbs have not even left behind vestigial bones and the breathing holes associated with them are also completely gone. This strongly implies that the limbs were not gradually reduced over time (like, say, the hindlimbs of whales) but, more drastically, that the arezoan equivalent of Hox-genes responsible for the development of a whole segment of the body has been deleted or suppressed.

Not helping with this is that the known fossil record of Mars is almost completely silent on the matter as well. Large, ungainly hexapods from both cuneocephalian and archaeocephalian stock, often grouped together into the polyphyletic group “Tagmasauria”, were once the dominant land animals during the Late Thermozoic Era (Sivgin 2345). Towards the middle of that era’s Cydonian period, the first deltadactylians suddenly appear with no known transitional forms. We have yet to find a cuneocephalian, both living and fossil, with an intermediate amount of limbs of just four or five. This strongly implies that this adaptation must have been so successful even in its incipient stages that selective forces acted fast enough towards its perfection that there was little time left for mosaic forms to leave a mark on the fossil record. A similar phenomenon is observed in the evolution of pterosaurs and bats on Earth, whose transitional forms are also unknown. But this opens up more questions than answers, for, unlike powered flight, there is no obvious advantage for tripedalism. As a general rule, the more legs an animal has, the faster it can run, so this would not have given deltadactylians an edge in the fight for survival against their earlier cousins. Their form of tripedalism, with only one front leg, is also extremely awkward and almost forces most of the lineage further down the line towards bipedalism. It also largely prevents the evolution of a sprawling gait, restricting them to an energetically consuming rectigrade posture. A betting man would not have put his money on this group surviving in the long run, but yet deltadactylians would go on to largely replace the “tagmasaurs” in the Late Cydonian period and the Hylozoic Era (though the rise of megafaunal periostracans may have been the bigger culprit there).

One attempt at an explanation has been that the great appendage evolved to cope with the lack of digits that onychognaths seem to struggle with (Budiman 2311). The whole phylum has ancestrally only had two fingers per hand and genetic quirks seem to prevent them from evolving more. The fusion of two limbs allowed the deltadactylians to have a hand with four digits, with which they could grasp objects. This explanation is not appealing for many reasons, however, as evolution does not work in such a goal-oriented way. The gaining of a grasping hand certainly was a neat byproduct of the fusion, but could not have been its initial cause.

At least when it comes to the loss of a limb pair, a more sensible suggestion has been put forward, which is that it has been lost due to being too energy-consuming. The extinction of large hexapods on Mars may not have been due to outcompetition by deltadactylians but rather because such large, multi-limbed bodies became increasingly harder to maintain with the changing of the atmosphere and the loss of much vegetation. The deltadactylian body plan definitely seems more efficient in that regard (even though a whole lung-segment has been lost) and is more than suited to outrun antitrematan predators, who have never been able to evolve more than three limbs. On that note, it is interesting that tripedalism never evolved on Earth but did at least three or four times independently on Mars. Possibly, the low gravity has an unforeseen effect on animal locomotion that makes this limb count more viable than we earthlings would expect.

References:

• Budiman, Daniel: Nothrotherium arabianum and the evolution of the deltadactylian (Cuneocephali, Onychognatha) hand, in: Current Astrobiology, 113, 2311, p. 45 – 67.
• Sivgin, T.K.: Life on a Dead Planet. The first 3 billion years of Evolution on Mars, Zürich 2345.

Tundras

The majority of the southern hemisphere of Mars consists of an almost continuous tundra. Life on the permafrost is hard, for in most places the temperatures rise above zero only for 134 sols of the year. In a few desolate areas this number can be well below 67 sols, while a few more fortunate ones have around 267 summer days, but in all of them the majority of the year is spent below freezing.

Apart from the red dust of the deserts, it is the tundra that gives Mars its red coloration. Polyfractarians are entirely absent from the flora, instead the most conspicuous organisms here are the red fronds, a type of monovexillan. As photosynthetic organisms they have likely evolved such a darkened coloration in order to better capture the faint light of a much farther away Sun. Red fronds have large, fleshy bases buried deep into the top-layer of the soil above the permafrost, which act as sugar storages for the long winters. The frond above ground is in a nearly desiccated and almost dead state during this time, with much of its interior water having been replaced by biologically produced anti-freeze. Photosynthesis halts almost completely during this time and the tundra becomes anoxic. Once the summer thaw comes, the top-layer of the permafrost melts and, because it can not drain away through the frozen underground, the water accumulates everywhere into bogs and ponds. The fronds seep up the water and spring back to life by digesting the anti-freeze proteins inside their body and producing their characteristic pigmentation. The whole tundra starts to bloom in bright red and photosynthesis resumes. These frond blooms occur on such a large scale that Earth-based telescopes have been able to observe them since the 20th century, giving humanity its first clue towards the existence of vegetation on Mars. The fronds use the short summers to produce as much sugar as possible for the next period of dormancy, as well as to produce spores. The majority of the fronds are asexual and their spores are carried by wind. These spores can stay dormant for a remarkable amount of time before germinating. Our scientists have been able to retrieve frond spores from a piece of permafrost that was at around 18’000 years old and when exposed in the lab to heat and light, they actually began to grow!

Fig. 2: Extent of tundraic climates. The small tundra-ring around the northern ice cap is not shown.

Sharing their environment with the fronds are various smaller spongisporians, which also stay dormant during winter. Though still capable of filtering the atmosphere for food particles, many of them have bumps and lichenous leaflets, in which photosynthetic endosymbionts live. The sporians profit from their production when the air is too empty, while the microorganisms profit from the protection during winter. These tundraic sporians reproduce much in the same way as the fronds.

Most fascinating is the scum-level growth of the tundra. Instead of grass, the most numerous organisms here are filulithophores, a type of filamentous macroareont, which carpets the whole biome. Like their pocupoan cousins, these are multicellular, though prokaryotic organisms that live through various forms of photosynthesis and possess tiny shells made of silicon dioxide. They are also red in coloration, though unlike in the fronds this is actually a structural colour achieved by the morphology of the shell. What purpose this serves is unknown. Filulithophores, like most macroareonts, are excellent nitrogen-fixers and are capable of enriching the tundraic soil with nitrogen amounts comparable to what is found in Earth’s tundras. Some hypotheses speculate that the low amount of nitrogen in the atmosphere of Mars might actually be their fault, though this is highly disputed. What is known is that many migratory animals from the equatorial regions get most of their nitrogen by feeding on the tundraic vegetation during summer. Unlike their mountainous cousins, filulithophores only grow a few centimetres tall, with most being in the millimetre range. They are the only organisms who seem to not go into a state of complete dormancy during winter, as most of their biomass is actually underground. Also present on exposed rocks, glacial erratics and naked soil are various species of flechtoids, similar to those found on the ice caps, but much more diverse and complex.

During winter, all animals larger than a few centimetres are completely absent from the tundra, having migrated towards the equatorial regions. The rest goes into deep hibernation underground. The sole exception is the yateveo, a species of wanderstalk with a bizarre survival strategy. Though largely sessile, it has almost completely given up photosynthesis and instead acts like a clam trying to be a carnivorous plant, by preying on particularly large wadjets during the summer migrations. It is a gamble, but when it pays off, it can feed off the trappings for the whole winter, thanks to its low metabolism.

 

Fig. 3: Observations of frond blooms from the 1960s.

In summer, things become much livelier. First come the herbivorous, power-flying variants of shellubim larvae, closely followed by the insect-like wadjets, which feed on the plankton and use the bogs formed by the meltwater to lay their aquatic eggs. These are then followed by larger flying animals, like vanators and the strange, hindwinged ballousaur onychognaths. On the ground also migrate various fusobranch onychognaths and bennus to feed on the frond blooms and sometimes to even rear their young in the tundra. Evidence, in the form of permafrost remains, exists that the tundra was once home to even larger animals. A few years ago, a quite sizeable, frost-mummified lower leg has been uncovered by an excavation team in deposits that are possibly around 100’000 years old. Beyond having been covered in characteristic feather-scales and belonging to some type of upright-walking cuneocephalian, not much can be said about the appearance of the leg’s owner, except that it was approximately the size of a reindeer or even a moose, much larger than anything currently alive on Mars. Soon after the discovery, some fringe theorists have claimed that a satellite image by the DIXON-4 Polar Orbiter actually shows a herd of these “Martian caribou” close to the southern ice cap still surviving until modern day, but all the low-resolution image truly shows is a couple of dark spots on an icy plain, which is much more readily explainable by flechtoid colonies or starbursts. The extraction of XGNA from the carcass has been unsuccessful, though as shown by the frond spores, younger permafrost remains might still be lucrative.

References:

• Fig. 3: Salisbury, Frank: Martian Biology. Accumulating evidence favors the theory of life on Mars, but we can expect surprises, in: Science, 136, 1962, p. 17 – 26.