Paroster bulbus is water beetle in the Hydroporini tribe of the subfamily Hydroporinae in the Dytiscidae family.[1] It was first described by Chris Watts and William Humphreys in 2004 as Nirripirti bulbus.[1] [2] It was transferred to the genus, Paroster, in 2008 by Remko Leijs and Chris Watts.[3]
It is known only from the type locality in Western Australia.[1]