A comparative study of the gill area relationships in some talitrid amphipods

Abstract

The total gill area and gill distribution of seven talitrid species taken from a variety of habitats have been studied. In the sandhoppers, Talitrus and Talorchestia, and in the landhopper, Arcitalitrus dorrieni, the greatest gill area is invested in the posterior gills (G6) whereas in the beachflea, Orchestia spp., G2 has the greatest area. Gills 3, 4 and 5 are characteristically small and G7 is consistently absent in all the species studied. Gill structure and deployment patterns are, in general, quite conservative within the Talitridae. The gills of A. dorrieni are, however, complex in shape and are more convoluted than in the other species studied. Gill area/body dry weight relationships were established for each species and are compared with previously published data. The Talitridae show a reduction in total gill area compared with most aquatic amphipods. It was observed, however, that the slopes of the calculated regression lines were significantly different between the sandhopper and beachflea genera studied. The reduction in gill area within the Talitridae is discussed in relation to their colonization of land.