Syncarpus

 
Thecocerates such as Cecrops are widespread across Mars, though mostly restricted to warmer regions usually above the 0 or 10° C-isotherm. Syncarpus sarahlandryi is the only known living exception to this, as it is found in the milder shrubland regions and during the summer thaw may even follow other migrants into the tundras.

Although not a true ectotherm like its northern cousins, it is not a homeotherm either. During the warm summer months and days, its metabolic rate is largely the same as that of relatives like Cecrops, strongly influenced by the temperature of the environment. But during winter, when it hibernates in dug-out burrows left behind by shetaw, its metabolism raises its body temperature notably above that of the environment. The same happens also when Syncarpus forages in the cold Martian nights. Such metabolic variability is on Earth only observed in a few reptiles such as tegus and pythons, though it seems widespread in Deltadactylia outside of the Thecocerata. It likely evolved as a compromise to handle the often extreme temperature changes throughout the year on the one hand and general food scarcity on the other.

Likely for the purpose of insulating its temporarily heightened body temperature, Syncarpus is also the only thecocerate that is not naked, but instead covered by an insulating integument. This integument is a plumage of frilled scales, very similar to what is found in the Banuptet and some other deltadactylians. It is possible that this is homologous, meaning that Syncarpus is a relic of a more ancient radiation with all other thecocerates having lost this trait. On the other hand, overlapping scales seem to be ancestral to the deltadactylian clade as a whole, so this may have just been an adaptation that evolved multiple times independently through parallelism. Skin data from fossil thecocerates is unfortunately lacking, leaving this an open question (Sivgin 2345). Interestingly, during ecothermic metabolic phases, Syncarpus uses little muscle fibres at the base of each feather-scale to raise them up, breaking the insulating effect to better allow environmental warmth to reach its body. During mating displays, where these hermaphroditic aliens determine who has to bear the young, this ruffling is also used to intimidate the partner into a submissive, breedable position.

Syncarpus usually gives birth as a single parent to two or three live, though underdeveloped, young in their burrows. Curiously, only one young per litter is lavishly fed, while the other siblings are neglected and have to fight for scraps. Once the spoiled child grows large and strong enough, it eats its weakened siblings, well within the parent’s wishes it seems. Likely the siblings only exist as failsafes in case should the favoured child die and otherwise are just a form of food storage, much like how on Earth some birds and frogs produce excess chicks and tadpoles as cannibalistic food rations. For this, Syncarpus has, rather morbidly, been given the nickname “Martian Curate” in some Terran books (see Grauel 2323 for an egregious example), in clear reference to the Synthologist Cult Massacre on the International Lunar Station. I strongly disapprove of such naming practices, as it needlessly demonizes these organisms and makes light of a truly horrendous tragedy.

References:

• Grauel, Trant: Martians from A to Z. Astrobiology explained for Kids!, New York 2323.
• Sivgin, T.K.: Life on a Dead Planet. The first 3 billion years of Evolution on Mars, Zürich 2345.