Paracrangonyx Stebbing, 1899, a genus of New Zealand subterranean amphipods (Crustacea : Amphipoda : Gammaridea)

Collections of groundwater crustaceans from deep (20 m) wells near Christch urch, New Zealand, included specimens of Paracrangonyx compactus, a poorly known species that is rarely collected. A second undescribed species in thi s hitherto monospecific genus was also present. Based on this material, the genus is re-diagnosed and P. compactus re-described in more detail. A new species, P. winterbourni, is also established. The two species differ appre ciably in body form and elongation of the peraeopods, but are remarkably si milar in most other respects. The genus is now known to be sexually dimorph ic in setation of the outer rami of uropods 1-2. Other important generic ch aracters include the absence of calceoli, second gnathopods that are slight ly longer than first gnathopods, slightly to greatly reduced coxae that are contiguous to discontiguous, sternal gills medially on peraeonites 2-7, co xal gills and oostegites on peraeonites 2 or 3-6, and glandular uropods.