The natural history of mudskippers in northern Australia, with field identification characters

We provide field identification characters and report on the natural history of mudskippers (Gobiidae: Oxudercinae) in Cairns, Darwin, Derby and Broome, northern Australia.Nine species in four genera are recorded ( Boleophthalmus birdsongi, B. caeruleomaculatus, Periophthalmodonfreycineti, Periophthalmus argentilineatus, P. darwini, P minutus, P. novaeguineaensis, P. takila and Scartelaos histophorus).The intertidal zonation of mudskippers conforms to previously reported patterns, but subtle differences in habitat preference are observed at both intraspecific and intrageneric levels, underlining the need for in-depth investigation of habitat selection by mudskippers.Although most species inhabit littoral mudflats, some show possible habitat expansion: juvenile Periophthalmodon freycineti are found occasionally in pools on a sandy shore, and a population of Periophthalmus minutus is found to be established in a marginal mangrove habitat (a salt flat behind a pioneer mangrove assemblage).Burrow confinement during high tide is confirmed for both species of Boleophthalmus, two Periophthalmus (P.minutus and P. novaeguineaensis ) and Scartelaos, but not for Periophthalmodon or the other Periophthalmus species.Territory formation is described for S. histophorus.