Pseudosterna

''This article is about the exoanimal phylum. For the bones found along the back of members of this phylum which connect the ribs, see Pseudosternum.''

Pseudosterna is the phylum containing many of Pontret's macro- and megafauna. Pseudosterns are easily identifiable by the presence of two rib cages, the thoracic cage and the abdominal cage. Along the top of each cage is a pseudosternal bone. The two psuedosternals meet between the rib cages, over the ultracostal region, to form a specialised joint similar to a ball-and-socket joint. The two bones collectively are called the pseudosternum.

Though part of its purpose is similar to that of the spine in Earth vertebrates, the notochord runs elsewhere, closer the the belly.

Taxonomy
Pseudosterna contains 6 classes.

Xenoavis
The eses. Features include jointed central limbs. greatly reduced exomandibles, beak-like endomandibles, chemosensing organs inside nasal chambers and a sinciputal er system which may be divided. Members of some orders are capable of powered flight.

Yaoortheria
Termed Yaoor in Nical, these organisms have four weight-bearinng limbs, whilst the central limbs are reduced, point upward and act as signallers for communication. Navigation and surroundings awareness are established mainly through the use of four ears, two above and two below the mouth. The exomandibles are substantial, usually covering the endomandibles entirely when closed. The chemosensing organs take the form of (usually retracted) antennae-like organs called nasobranchi, present alongside or underneath the exomandibles. In some groups, these are highly important organs for communication by pheromones and for navigation, even equalling the ears as for importance, especially over long distances.