For biology see Kivanians
The Tylanians are a historical curiosity. The species originates on Kivan, and is in fact Kivanian, though neither race will agree with this assessment for certain sociological reasons.
Before Kivanians developed faster than light travel there was a major social and political schism. Due to the pack nature of the race certain disagreements involve ejection from the pack. In this instance the Tylanians were ejected from the species and exiled from the homeworld. Due to the long separation, first by logistics of distance and later due to a mutual distrust and tendency to avoid one another the Tylanians and Kivanians have evolved sufficiently different society, governemnt, language, and the very earliest signs of genetic divergence such that they are accepted by many as a distinct race if not as a distinct species. As it is debated even among their own scholars if it was within their ability to actually eject someone from the species no serious effort is made to classify them, biologically, as separate, but a popular practice in deference to the two races’ wish to be counted apart unofficial subspecies nomenclature and denotion is often used.
The Tylanian story is lost to full fledged history. Though tradition and legend remain to give an idea.
The schism, according to both races’ legends dates back in the time that the Imperium was first trying to form. It is known that this would place the time of the event well after the species had developed space flight, and had achieved a level of refinement that it was a reasonably cost effective, and not inconvenient investment of time to travel the worlds of the Kivanian home star system.
The exacts of the argument seem to be lost even to legend, but it seems that the Tylanians were opposed to, either the formation of the Imperium and its entire setup or to the first selected Patriarch and Matriarch and were exiled from the race. Tradition and legend among both races differs if it was self imposed exile or not as there are provisions for exile from the Imperium that, in essence, excommunicates one from the Kivanian race since you are stripped of both family and clan name and not allowed back into the dominion of the Kivanians. The Tylanian schism, if it was such an event, was the only time such was done on any scale larger than a dozen individuals.
They left in a generational ship that had a very good sublight drive and the theories that led to the first Kivanian FTL had been concieved. Tylanian history suggests and legend plainly states that within three generations of leaving their home they successfully made use of those theories and so converted their colony ship to such which is how the Tylanians are so far from their planet of origin with an old and established society, and rich, vibrant cities instead of still being a number of years from reaching it (they, in fact had been exiled to a different star, much closer to Kivan but liked neither the proximity to the Imperium, nor the need to kivaform the only remotely habitable planet in that system while continuing to live on the generational ship during that process which was estimated to need three hundred years to complete).
Today the Tylanians are a race that has been, historically, a kind of democratic monarchy electing a king and queen that rules with the aid of a group loosely translatable as a parliament (please note that this is only loose translation and ignores certain nuances of powers and responsibilities). They still seem to follow a form of the Kivanian traditions of ancestor worship if less varied, and The First ancestor seems to have a role as closer to a full deity and bringer of all life and death.
Their diet differs little from Kivanian since their ship was sent to a world known to need kivaformed to live on and as such had brought much Kivanian livestock and seed with them both for use on the ship as well as on their new home. Some took to the new world better than others and a few cross pollenated with native plants so their Kivanian foodstuffs are not all perfectly parallel and too the diet takes into account many native plants, animals and insects. Of interesting note is the Tylanian habit to prefer mollusks, land and sea, as well as crustaceans in dishes where Kivanians typically would use fish or poultry.
It should also be noted that either the sacredness of Kivanian passions was not a typcial or even existent belief at the time of the schism (a common interpretation as it took place before the species had met other sentient races) or they abandoned this philosophy at some point. A Tylanian makes a far greater effort to manage the extremities of their emotional state than many Kivanians are likely to ever consider healthy, or sane.
Tylassia, the Tylanian homeworld, is significantly closer to Terran controlled territories than the Imperium’s worlds and, between this and the ‘greater emotional stability’ of the race, the Tylanians have a better relationship with the Terran Confederation.