The Satyriacs were a posthuman species that evolved from the Hedonists.
After millions of years in which the Hedonists lived in constant pleasure, cataclysms shaked their planet and their continent, no bigger than Iceland, was expanded into bigger landmasses roughly the size of Australia. The same cataclysms produced vast amounts of ash which blocked out the sun and led to the decline of most plant life and therefore also most of the Hedonists.
Only a few fast-breeding mutants survived and managed to repopulate the world with many species. One of them were the Satyriacs, sapient creatures which had a "tail" made out of pelvic muscles which gave them an almost dinosaurian stance.
For a while, there were three empires, then two, before all of them split up into myriads of countries, which later reunified into one world order. Like their non-sapient ancestors, the Satyriacs once again loved life and enjoyed it to the fullest in their newly built paradise, with festivals, concerts and orgies every week.
During the following ten million years, other posthumans joined in on the communications, including the Modular People, Pterosapiens and Asymmetrics. After another 20 million years, the empire also included the Saurosapients, Snake People, Symbiotes and the Sail People. Only after fourty million years, the Bug Facers joined in.
Over a timespan of about 80 million years, the Second Empire developed, through the combined effort of all members, into a galaxy-spanning empire, even though the members never met each other personally, and all of the species colonized other planets.
Though they were prepared to face an alien invasion, the Empire didn't think about an invasion from other posthumans, and so the Satyriacs, along with all of their cousins, were quickly wiped out by the Gravital as part of their interstellar conquest.
- All Tomorrows, by C. M. Koseman (2008)