The Riposte are a sapient species native to the Venus-like planet Scaramouche. They are a form of "barocapnic" life - silicon-based organisms that use supercritical carbon dioxide as a solvent.
Biology[]
Anatomy & Physiology[]
Riposte are colony organisms consisting of two separate zooids with a single shared head. The head is broad and flat like a hammerhead shark's, and the two bodies are long and serpentine. The head has an eye on each side and two mouths on the front, with one leading to each body. The entire organism is covered in simple feathers except for the underside, which is covered in adhesive scales. To human eyes, Riposte have a dull orange-red color with a white underbelly, but in the polarized light the Riposte see, they are far more vibrantly colored.
Riposte are significantly larger than humans, averaging a total length of 4.8 meters (15.75 ft). The head alone is 1.4 meters (4.6 ft) wide. However, because the supercritical carbon dioxide they use as a solvent is much less dense than water, they only weigh 26 kilograms (57 lbs) on average.
Biochemistry[]
Riposte are silicon-based - any carbon-water organism would die instantly in the heat and pressure of their environment. They use supercritical carbon dioxide as a biochemical solvent. Since this is a fairly poor solvent for silica compounds, they supplement it with eutectic salt mixtures. This biochemistry requires temperatures of 700 to 800 K (427 to 527 C) and pressures of 80 to 120 bar.
Animals on Scaramouche, including Riposte, obtain energy by reacting carbon dioxide with calcium oxide from food to produce calcium carbonate. Carbon dioxide is breathed in and absorbed by the animal's tissue, and the calcium carbonate is excreted by the digestive tract.
Diet[]
Riposte are generalist herbivores, feeding on the plant analogues in their environment. They prefer seeds and fruit from nemosynthesizers and biofilms from photosynthesizers. Riposte feed by everting their mouths to grab food and swallow it whole. Food is taken to the gizzard, a complex organ which allows the Riposte to consciously sort through ingested food before sending it to the stomach or regurgitating it.
Fabricator System[]
The digestive tract of one of a Riposte's bodies forms a fabricator system, a unique organ with no Terragen analogy. This system can secrete eutectic salts and shape them into highly complex structures. The salt can either be used as a building material in its own right or as a glue to hold ingested and regurgitated materials together. In this way, Riposte can build and use nearly any tool they need.
Reproduction and Life Cyclce[]
Riposte have two sexes, which are never referred to as male and female, and show minimal sexual dimorphism. The reproductive process begins when a pair of Riposte, one of each sex, build a nest together. They then build an egg case, in which they mix spawn from their fabricator bodies, before placing the egg case inside the nest. Incubation lasts two months and produces a single wormlike "monad" of animal intelligence. After four months, either two or four zooids bud from the monad's head, killing and consuming it. Two zooids form one baby Riposte, while four form a pair of babies. Riposte reach sexual maturity at the age of 23, but usually leave their parents at a significantly younger age - between seven and twelve.
Homeworld[]
Riposte are native to Scaramouche, a Venus-like terrestrial planet orbiting the K-type star Pantalone, which lies 6,070 light-years from the Sun. Scaramouche is the innermost planet of the system, orbiting at a distance of 0.374 AU over a period of 93.1 days. Scaramouche rotates on its axis once every 56.24 days. The orbit and rotation combine to create a solar day of 142 days. Unlike Venus, Scaramouche is very slightly larger and heavier than Earth.
Scaramouche has an atmosphere of 96.9% carbon dioxide and 3.1% nitrogen, with only trace amounts of other gases. The surface temperature averages 750 K (477 C, 890 F), and the surface pressure is about 100 bar. Under these conditions, the atmosphere at the surface is a supercritical fluid rather than a gas, allowing it to act as a solvent and making barocapnic life possible. There is no liquid of any kind at the surface, but this poses no challenge to native life - the "air" itself is the solvent they use.