Creature:Pnolthane/Biology

The Pnolthane species is very obviously sexually dimorphic with females being heavier, taller and stronger than males by a measurably significant margin as well as having a different average shape to their bodies, a larger, spinier beak, and having different feathering patterns. In addition to this, female Pnolthane live twice as long as males on average.

Evolution
Pnolthane evolved from an ancestral quadopteric bird species that lived in the warm forests of Southern Aglaisia, a region known today as Ezerona. The Pnolthane are considered to have diverged from this species approximately 70 thousand years ago.

Ancestrally, like all quadopteryx, the Pnolthane had four wings which they used to navigate the tall forests for ancient Aglaisia. However, increased volcanic activity on Pnolthanus lead to a global increase in temperature which caused Ezerona to become less forested and more grassland-like. This meant that flight was less useful as there were fewer trees to fly between and prey was more often found on the ground. This meant that as the benefits of flight diminished, the energy cost to flight and maintaining four large wings began to outweigh and so four wings was selected against and flight ability reduced.

Over time, this lead to the development of two wings and two forelimbs. As they were no longer needed for flight, these forelimbs had a greater degree of freedom, evolving to become better at manipulating the environment with a taloned hand. Evolutionary remnants of these arms' original purpose can be seen by the feather tufts that still exists around the wrist.

Greater manipulative ability of the hand allowed for greater food accessibility both due to the ability to now acquire harder to reach food like root vegetables as well as better tool making which lead to food sources such as bone marrow. A large, complex brain has a high energy cost but this better access to food partially offset this cost while allowing for the benefits of a larger brain such as better abstract thinking skills and language skills which allowed for even better toolmaking/access to food, creating a positive feedback loop where the brain could evolve to be even larger/more complex. Coupled with excellent eyesight, this provided the advantage of allowing the Pnolthane to better identify brood parasites like the Deathchild bird, increasing reproductive success.

Anatomy
The Pnolthane skeletal system is mounted on a central spine made of interlocking vertebrae. Pnolthane bones are light due to the fact that they're hollow, containing only a thin matrix of bone fibers for strength. Bone tissue contains similar proportions of calcium and magnesium, both important nutrients in the Pnolthane diet. The muscular system is anchored to the skeletal system. Pnolthane muscles work simply my contracting long muscle cells to pull on the skeleton, moving it. Pnolthane have two types of muscle; dark and light. Dark muscles are used for high-energy endurance activity such as flight and so are very energy efficient and so not tire easily while light muscle is used for shorter, more rapid activity such as limb movement.

The center of the Pnolthane nervous system is the large brain located in the head. This is divided into three main sections. A large forebrain is responsible for relational and abstract thinking as well as sensory processing and emotion. The cerebellum is responsible for motor function including the complex muscle movements needed for flight, this accounts for the cerebellum's large size.

The Pnolthane circulatory system is distributed through the body by green arteries deep in the body that have thick walls and carry blood under high pressure from the hearts and pink veins that are closer to the surface and carry deoxygenated blood back to the hearts under low pressure. The circulatory system is bicardial and is centered in chest where the three main organs of the system reside. Deoxygenated blood is pumped into atrium of the pulmonary heart where the muscular walls of the organ contract and push the blood through a one-way valve. Additionally, the pulmonary heart draws newly produced blood. The production of new blood cells to replace excreted dead cells is centralized and occurs in the sanguim, a large organ in the center of the chest. Due to its vital nature, the sanguim is heavity protecteched by a second, smaller rib cage that lies under the primary rib cage. The blood is then pumped through the major lung on one route and the minor an ancillary lung on a second route, converging back in the constitutional heart. The constitutional heart then pumps the newly oxygenated blood throughout the arteries distributed through the body.

The Pnolthane respiratory system is fed through the mouth and nostril holes in the beak. During inhalation an air sac at the base of the lungs fills with air while a diaphragm above relaxes, allowing oxygen-depleted air to exit the lungs into a second air sack above the lungs. During exhalation this air sack empties and the carbon dioxide-rich air leaves the body. The still oxygen-rich air in the lower air sac simultaneously enters the lungs, re-enriching the blood with oxygen. This system evolved in ancestral Pnolthane as a result of the high energy demand associated with flight causing this feature to be selected for as the additional stored oxygen allows for greater metabolic rate.

The Pnolthane digestive system begins in the beak. Food is not processed here by chewing although harder foods like nuts can be cracked open by the sharp edges of the beak and the powerful muscles that drive it and food can be broken into smaller chunks before entering the mouth. food then travels down the esophagus into the crop. This expanded muscular pouch is used to store a volume of solid food eaten prior to digestion. At the base of the crop is the proventriculus. This organ is analogous to the the stomach although does not have as much volume and secretes digestive enzymes that break down the peptide bonds in food as well as chloric acid while churning solid food through movement of the thick muscular walls. The food then passes into the gizzard, a large organ with strong muscular walls that contract to process the food by grinding it into smaller parts since this process did not occur in the mouth through chewing. Ancestral Pnolthane swallowed stones to aid this process, acting as 'teeth' to aid this process. However, modern Pnolthane use artificial gizzard stones, often with extra functionality. This processed food then passes into the intestine where nutrients from the food is extracted and enters the bloodstream, additional digestive enzymes being added from the liver and the dual pancreases. Material with no nutritional value that can be absorbed is stored and dehydrated in the a large organ called the stercum before being expelled from the body through an opening called the cloaca. Toxins are extracted from the blood by one two-lobed kidney and secreted with uric acid into the stercum to be excreted with the solid waste.

Pnolthane vision is tetrachromatic with retina featuring cone cells sensitive to red, green and blue wavelengths as well as cones sensitive to ultra violet light. This ancestral species with aerial hunting as the urine of their prey contained phosphorous compounds that would fluoresce with ultraviolet color in sunlight, indicating the location of prey nests. A structure unique to Avianoid life on Pnolthanus is the pecten which is a comb-like structure of blood vessels that protrudes from the point at the back of the eye where the optic nerve is attached. The function of the pecten is to regulate the pH of the fluid within the eye and to nourish the rod and cone cells on the retina. The advantage of such as structure is that it allows fewer blood cells within the retina itself which means that the light sensitive cells can be more densely packed. This, coupled with their forward-facing eyes allowing for depth perception means that Pnolthane have very sharp eyesight, able to see fine detail at a great distance.

Physiology
The color of Pnolthane feathers is caused by a pigment protein called Vermiculin which can occur in various concentrations depending on an individuals genes, leading to variation in red hue, lightness and intensity between different populations of Pnolthane. This protein acts like a natural sunscreen, absorbing harmful ultraviolet radiation to preventing feather damage.

Pnolthane blood is green. This is a result of the oxygen-carrying green blood cells which are filled with a green protein called prasinoglobin which is based on nickel compounds. These cells are suspended in a salt-filled plasma. Other cells present in Pnolthane blood include warrior cells which are responsible for destroying invading pathogens as well as remembering the signatures of past invaders and blue blood cells which are responsible for neutralizing various types of poison and other harmful chemical compounds in the blood stream.

Reproduction
Like all Pnolthanian life, the Pnolthane's genetic material is contained within dXNA chromosomes. Pnolthane have 156 chromosomes, 153 somatic chromosomes and 3 sex chromosomes. These sex chromosomes have two types, W and Z. Every Pnolthane has either WWW or WWZ in their genotype, WWW individuals being male while WWZ indididuals, female.

Pnolthane gametes are produced during meiosis where one of the three sex chromosomes of an individual is randomly selected to be part of the gamete formed. As they only posses W chromosomes, males will always form sperm containing them. However, females have a ⅓ chance of creating egg cells contain Z chromosomes and a ⅔ chance for W chromosomes. In order to be fertilized, an egg must join its genetic material with two sperm from a male, accounting for the fact the fertilized egg will have three total sex gametes. This mechanism evolved as a way to increase the variation in the alleles in the fertilized egg which is beneficial to the species as a whole. because of this, male Pnolthane hatch more frequently than female.

A rare chromosomal disorder called 'Monarch Syndrome' exists where an individual may hatch with two Z chromosomes. This condition is not fatal due to the remaining W chromosome but leaves the individual with physiological complications due to severe hormone imbalance such as over-growth, especially in the bones. However, these individuals are sometimes fertile and will produce have an increased chance of having female offspring. The condition is so named because of Empress Nortra IV, a historical ruler in northern Aglaisia who was physically imposing and had a powerful bloodline of an unusual number of females due to her having the condition. As the Z chromosome is much smaller than the W and does not contain many of the genes necessary to life, having a ZZZ genotype is always fatal.

The external sexual organs of both male and female Pnolthane are cloacae which, aside from being used to excrete waste from the digestive system, are used to by the ovaries/testes to discharge sperm/eggs. Pnolthane mate seasonally where, during the right time of the year, the cloacae of both sexes become swollen and the females become sexually receptive. Pnolthane copulate by rubbing chloacae together, the male releasing sperm into the female. This process releases endorphins in the brain for both individuals, making the experience pleasurable. because of this, many individuals will copulate even when reproduction is not the goal.

When sperm has fertilized an egg yolk, the female will secrete an albumen around around the yolk and then muscular walls of the oviduct will contract to form the shape of an egg. A shell of calcium carbonate and magnesium carbonate will form around the yolk to protect it as it develops. The female will then lay the egg and incubate it for a period of five months until it hatches into a bald, blind chick. However, Pnolthane technological development has allowed to the construction of brooding machines which can incubate the egg for the mother while she is free to spend her time on other activities.

The mating season is called Avina and takes place during the Pnolthanus Spring. Only during this time is it possible for individuals to release gametes and lay fertilized eggs as during other times of the year, the hormones that cause the cloacae to be engorged will not be released. Due to the relatively short nature of this mating season, many Pnolthane typically have between one and three children in any one year.