- You may be looking for their reptilian successors.
The mammalian Betrushians were the first sentient race to evolve on Betrushia.
Biology
The mammalian Betrushians were humanoid with shrew-like faces and yellow eyes. (PROSE: St Anthony's Fire)
Technology
The mammalian Betrushians were a highly advanced race in a variety of fields.
One of their creations was a type of organic catalyst which was able to test for biological viability of an organism and which would destroy any which were unsuitable. They were also able to create an ring of satellites which inhibited the catalyst and trapped it on the planet.
The Betrushians were also able to create a holographic chamber which recorded their history and could play it back for later generations. (PROSE: St Anthony's Fire)
History
Millions of years ago, the Betrushians had an advanced civilisation. Unfortunately, their attempts to create a catalyst that could test for inadequate species was a failure and the catalyst lead to the extinctions of their species. Before this, the Betrushians were able to create the rings of Betrushia which trapped the catalyst on the planet and were able to leave a Polygon with the history of the experiment.
This event lead to a racial memory in the surviving species on the planet, specifically in the second Betrushian's legends of the Keth. (PROSE: St Anthony's Fire)