ABSTRACT
This chapter analyses laboratory studies on the physiology and morphology of fishes in the gobiid subfamily Oxudercinae, which contains the four amphibious (Scartelaos, Boleophthalmus, Periophthalmus, and Periophthalmodon) mudskipper genera and six other genera that are either less- or entirely non-amphibious. Fishes transferred to scripps institution of oceanography were maintained in seawater aquaria and fed bloodworms or Spirulina algal flakes to satiation three times per week. The mass-specific gill surface area of S. histophorus shows a good fit, between Pseudapocryptes and other mudskippers, along the progression of declining gill area with the degree of specialization for terrestrial life. The flying fish Exocoetus monocirrhus, which presumably uses aerial vision to look for predators in water prior to landing, also has round lenses and thus does not gain aerial visual acuity by this compensatory refraction method. Species of the gobiid subfamily Oxudercinae offer insight into the sequence of character acquisition leading from aquatic to terrestrial life in the early vertebrates.
