The long strange trip
Minor Human Races
As well as the three recognized Major Human Races (Solomani, Vilani, and Zhodani), there are 46 Minor Human Races known to the Imperial scientific community (though some dispute this classification). Many human races are indistinguishable from each other though a few began from a small gene pool and/or developed in an extreme environment develop unique characteristics.
The Ancients transplanted populations of Homo sapiens antiquus to more than a hundred worlds. On a large number of these the populations survived down into historic times. Some have become extinct between the time the Vilani first invented jump drive and the present day. Some became so intermixed with Vilani that they ceased to have a distinct existence. Others simply died out. Some were exterminated by the Vilani.
By 1100 there were 49 human races (including the three major ones) known to Imperial scientists. At least one more (the Loeskalth) are known to exist, but the news has not yet been accepted by the established scientific community of the Imperium.
90% of all known homeworlds of human races, surviving and extinct, lie within a kidney-shaped area that stretches from the Spica sector to trailing to the Eiaplial sector to Spinward. This means, of course, that 10% lies outside this area. If one gets far enough away from the Imperium, one may even encounter MHRs that are not part of the canonical figure.
Many human races are indistinguishable from each other without genetic testing, though a number of them began from a small gene pool and/or evolved in an extreme environment and developed unique characteristics. Some were tampered with by the Ancients.
Two examples are:
Darrian live in a small group of worlds immediately spinward of the Imperium. Such is the cosmopolitan nature of Darrian society that, within Darrian borders, you can find ‘pure’ Darrians, Aslan (mostly citizens of the Confederation, although a small number of Ihatei have been allowed to settle on Darrian worlds), Zhodani and Imperials. Darrians mass slightly less than other Humans on average, probably due to their origins on a low-gravity world. Their taxonomic name is Homo sapiens darrianus.
The Suerrat homeworld is Ilelish (Ilelish 2907). The Suerrat claim to be a Major Race as they independently developed interstellar travel. However this was based on generation ships, not jump technology, so the claim is not accepted by other races.