Gill morphology and formulae of crayfishes (Decapoda: Astacidea: Parastacidae) from New Guinea and New Zealand and a comparison with other selected species of crayfishes

The Infraorder Astacidea comprises four superfamilies of decapod crustaceans: the freshwater Astacoidea and Parastacoidea and the marine Enoplometopoidea and Nephropoidea. The gill morphology of four species of crayfishes belonging to Astacoidea and Parastacoidea, two coral reef species of Enoplometopoidea, and 2 deep-water species of Nephropoidea are described and illustrated for comparisons and to determine characters characteristic to members of the family Parastacidae (Parastacoidea) from New Guinea. Morphology of the arthrobranchs and pleurobranchs were similar among all species, having a single stem with filament, but podobranchs of the parastacoideans differed from those of Astacoidea, being corrugated and tubular and having filaments. The astacoidean P. virginalis had a plate-like lamella with filament. The two nephropoid and two enoplometopoid species were similar to each other; their podobranch had a flat blade-like lamella without a filament and a shaft with a filament. The gill formulae of the New Guinea species of Cherax were the same as those of the Australian congeners, but the formula of the New Zealand Paranephrops planifronsWhite, 1842 was the same as those of the South American parastacids.