Dispersal among populations of Caridina sp (Decapoda : Atyidae) in coastallowland streams, south-eastern Queensland, Australia

Caridina sp. is an atyid shrimp occupying coastal streams in south-eastern Queensland and northern New South Wales. Shrimps from two geographic region s in south-eastern Queensland were examined. An analysis of 7 allozyme loci showed very high levels of genetic differentiation among catchments (F-ST = 0.65) with much lower levels within catchments. This indicates extremely limited dispersal among catchments with greater levels within catchments. T he levels of genetic differentiation were even greater than previously repo rted for two other atyid shrimp species occurring in upland rainforest stre ams. Populations from the Noosa River were more similar to those from the G lasshouse Mountains than to those from the geographically closer Tin Can Ba y streams. This pattern was remarkably similar to that of a fish species oc curring in the same streams and may reflect a recent confluence of streams from the Glasshouse Mountains and the Noosa River regions.