Tyranids are based on the arachnids from Starship Troopers [1]. Space Marines are based on Star Wars Stormtroopers. Not to say Darth Vader himself. Have a gande

Tyranids are based on the arachnids from Starship Troopers [1]. Space Marines are based on Star Wars Stormtroopers. Not to say Darth Vader himself. Have a gander at their helmets! _____________ [1] My source for that is the first novel in the Horus Heresy series. In one episode, some marines are on a far-away planet fighting a race of "megarachnids" which are very clearly some kind of forward force of the Tyranids. "Very clearly" given that the Marines are basically slaughtered. They get better. The internet tells me the planet was called Murder. The internet also is categorical that the megarachnid are a different species than the tyranids, but far as I can tell nobody has any real reason to say that, they all seem to just state it as a fact without further justification. So I says they were early 'nids.