Spinegaunt
Back in the good ol'days of 4th Edition, Games Workshop for some reason, decided to split the Termagaunts with Spinefists into their own separate categories. These 'Spinegaunts' (Guantii Spinodactylus) are a species of Tyranid belonging to the genus Gauntii.
Overview[edit]
They are some of the least complex Tyranid organisms like all things coming from the Gauntii genus. They have become adapted to wield Spinefists Biomorphs, which allows them to unleash a hail of poisonous spikes.
They continued existing as a independent unit for one more Edition in 5th, until some guys in GeeDubs realised they were kind of redundant, and then promptly rolled these guys back into the Termagaunt family once 6th Edition started rolling.
They still exist in the fluff by the looks of it, but on the tabletop, Spinegaunts are now considered as a count as-unit. So any Termagaunts with Spinefists are now automatically referenced as a Spinegaunt.