Nirripirti arachnoides Watts & Humphreys, 2004 Paroster arachnoides 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 arachnoides.

[1][2] It was transferred to the genus, Paroster, in 2008 by Remko Leijs and Chris Watts.

[1][3] It is known only from the type locality in Western Australia.

[1]