Direct evidence for aerial egg deposition in the burrows of the Malaysian mudskipper, Periophthalmodon schlosseri

The presence of mudskipper eggs in an air-filled chamber was confirmed by direct endoscopic observation of intact burrows of Periophthalmodon schlosseri in a mudflat in Penang, Malaysia. For all five burrows from which video images of egg chambers were successfully obtained, the presence of air was unequivocally demonstrated by the existence of an air-water interface inside the chambers. Of these burrows, eggs were found in two, but not in the others. Eggs were laid uniformly in a monolayer on the inner top surface of the chamber. The much brighter color of the surface mud of the egg chambers than the surrounding mud, irrespective of the presence or absence of the eggs, suggested that the surface mud had been oxidized by deposited air.