A new and unusual species of Haptoglossa

Abstract

Haptoglossa elegans, isolated from soil and organic debris in New Zealand forests, is described as new. This species has no motile stage. The protoplasm inside the thallus cleaves into spherical cysts that are expelled en masse to the exterior through a solitary exit tube. Cysts are two sizes. Small cysts produce elongate, unbranched, tapering gun cells. Large cysts produce identical but larger cells; alternatively large cysts produce Y-shaped gun cells. Haptoglossa elegans is a common and aggressive parasite of bdelloid rotifers but unlike all other species of Haptoglossa, it does not attack nematodes.