Anatomy

Interestingly, many Xi’ialoan species are opportunistically parthenogenic, in which females can give birth to fertile, clonal eggs. Individuals will often mix their clonal egg genes to prohibit population stagnation. Many more adaptive species additionally utilize syngamy (sexual reproduction), increasing the diversity of gene expression. For many species, reproductive strategy varies by season, with mass clonal spawnings helping to balance population levels that may be vulnerable to fluctuating conditions, such as climate shifts, storms, and the barrage of wet season diseases and parasites that take advantage of integumentary respiration. 

Organisms lack centralized hearts; instead, a capillary network facilitates nutrient flow osmosis and interstitial fluid. Powered by arterial pressure, pneumatic muscles contract and pump for movement. Due to the importance of maintaining internal fluid pressures, osmosis, and higher rates of transdermal water evaporation, many organisms have secondary, webbed structures on limbs and feet to gather H2O from water bodies and microprecipitation.

Large-scale networks of ganglia working with smaller, centralized brain centers control nervous systems. Eyes are widespread, and photoreceptive eyespots confer well-developed night vision to many faunal classes. Ears appear as lateral cranial openings. Sound travels ~3.6x faster through hydrogen than air, leading to appreciably faster faunal reflexes for predators and prey alike. 

Flying organisms of the class Sweala utilize pneumatically-muscled wings for flight, which expand for take-off and retract while on the ground. Most flying organisms spend the majority of time airborne, only landing to drink via webbed appendages that absorb water. They range in size from pterosaur to finch, with photoreceptive eyespots on the fronts and backs of their heads after evolution lost touch with side-based eyes like those present in Geanta. As such, they typically live near sources of water, and feeding either occurs when the organism is already on the ground or while the organism is in constant motion flapping its wings. They often perch in sprigs in order to facilitate rest, and many species enter a slowed metabolic state called torpor. Reproduction is entirely parthenogenic, and they lay hard-shelled “eggs” of their genetically identical young near water.

In a thin atmosphere, flight is a challenging proposition; flying organisms require more energy to take off and remain airborne. Xi’ialoa’s higher gravitational constant of 12.75 m/s2 further intensifies this effect, but lighter skeletal frames, proportionally larger wings, and the use of internal pure hydrogen gas each allow organisms on Xi’ialoa to achieve lift (and, by extension, flight) in a similar manner to Terran organisms. 

Class Sugara species possess unique, long, pointed, and retractable radulae that allow them to bore into the trunks of sap-producing sprigs. Sap is their only source of sustenance, which means they spend almost their entire lives feeding on just one sprig. Some Sugara species have evolved external respiratory vents akin to nostrils. The lures on top of their heads (thought to have perhaps been photoreceptive organs at one point) are bioluminescent, creating a strikingly beautiful environment wherever they reside. Females select males with brighter lures, a delicate balance between reproductive favoritism and increased predation. 

Members of the class Scana have two "necks" (a currently unexplainable occurrence) and large, expanding head crests that aid in hydrogen exchange due to the almost impenetrable nature of their tough, defensive scales which otherwise impede integumentary respiration. Some Scana members also evolved large, fan-like tails for gliding from sprig to sprig, while others are aquatic.