[Retric]

Tyranids where part of the 1987 version of 40k and barely mentioned. Genestealers were first introduced in the board game Space Hulk published in 1989 and introduced into the Tyranids well before Starcraft’s release date.

1993, featured the Tyranids in the supplemental books Wargear and Codex Imperialis, and then later in their own devoted army Codex.

By comparison Starcraft 1 is from 1998 at which point Tyranids had gone through multiple revisions and had fairly close to their modern lore.