A redescription of Paralimnadia urukhai Webb and Bell 1979 with the description of a new species P. minyspinosa (Crustacea: Branchiopoda: Limnadiidae).

Abstract

Clam shrimps of the genus Paralimnadia living in small pools of the eastern highlands are particularly variable between populations. A detailed study of many populations of P. urukhai in the northern New England Tablelands revealed almost random variation in normally conservative characters such as egg morphology and cercopod setae as well as wide variation in other less defining characters. This necessitates a revised description of this species. This redescription focuses only on the Stanthorpe group of populations as previous genetic analysis suggests the Bald Rock populations could represent a separate species, but the two cannot be separated presently based on morphological features. However, two populations 100 km to the south are morphologically and genetically distinct enough to constitute a new species which we describe herein. All these populations live in isolated rock pools within forests where dispersal is difficult, so that retained founder effects and local adaptation are probably directing interpopulation variability.