Felinids

Felinids are a minor race of abhumans in Warhammer 40k.

Official Canon
Felinids are a race of abhumans from the planet of Carlos McConnell. This is the full extent of canon information about them.

TTS Canon
In TTS, a group of Guardsmen make contact with the planet, with several of them excited to "see some catlady action," believing the Felinids to be a race of catgirls. When the Felinids' diplomat arrives, the guardsmen look on in horror, as it is a housecat with a human head and speaking in creepy, halting voice similar to that of a cat attempting to speak human language.

The Emperor decreed to have Felinids be among the mutant "transfer brothers" sent to the Black Templars to temper them. Helbrecht was not enthusiastic about having "cat-people" among his ranks.