Deep in the swamps... somewhere... there were Petalura... *creepy intonation*
Yeah, I'm not too good at stories, so here is some general information.
Petalura are not huge, averaging around the size of a golden retriever (in height; they are considerably longer and lighter). They are intelligent, nay, sentient, but they simply cannot reproduce the sounds of the English language. Some try hard to learn, but most only master a few words before giving up. They generally need some sort of translator to communicate with their owners. Their native language is surprisingly vocal for animals not able to speak a human language, consisting of hisses, clicks, growls, whistles, and trills in a variety of pitches.
Petalura prefer to spend their time in trees and in the air. They can manage on the ground, but their wings get in the way most of the time.
Petalura tend to be social, family being the most important social structure for them. Ancestors are greatly revered.
Concerning the ubiquitous and mysterious code:
Suishii likes to ramble on and on about the 'code'; that little string of letters at the bottom of the cert there. She also doesn't like to explain herself or give up any secrets before she thinks it's the right time, but I'm gonna have to lay it out straight for you guys.
The code represents a string of inheritable traits that each Petalura has. We only know of a few, but with these we can basically tell what any given Petalura will look like given only its code, and also be able to tell what its offspring will look like, since each Petalura passes on half of its genetic information to each of its offspring.
In the code there are a series of paired letters, each representing an allele; half of the information passed to that Petalura from its parents. Two alleles, one from each parent, make up a whole gene. These alleles come in many forms, some as simple as dominant and recessive, but some much more complicated.
The genes in the code control what traits the Petalura may exhibit, such as markings or color. One gene might control one trait, or there might be a group of many genes behind it. For example, the first gene in any Petalura's code is the T gene, which may have any combination of two alleles in it: T' or T. This particular gene controls the tail. I'm not exactly sure
how, but this gene determines what the tail will look like.
There are lots of other genes, but there are a finite amount of ways those genes may be expressed. For instance, there are only five types of markings on a Petalura: stripes, gradient, spots, rosettes, or none. A Petalura's genes only allow for those five. Some genes allow for more than this by being able to blend traits. Markings, however, cannot be blended.
More to come, maybe.
There are three of them! Stages, I mean.

Egg. On a pillow. Pretty mysterious.

Baby. And those are cute. At this point, one can be relatively sure what it will look like, though there may be some surprises in development...

Adult. Your Petalura is grown and its phenotype is fully apparent. It can now breed.
From egg to baby is one week, and from baby to adult is one week. Simple, huh?