Food habits and reproductive biology of the Australian legless lizards (Pygopodidae)

The Pygopodidae are an endemic Australasian lizard family, virtually limbless and with elongate bodies. Dissection of 595 museum specimens of 11 species (4 genera) provided data on body sizes, sexual size dimorphism, sex ratios, reproductive cycles, fecundity and food habits. Females grow larger than males in all species studied. All are oviparous, producing two eggs (occasionally, one or three) in summer. Most species feed on invertebrates. Pygopus nigriceps, Delma inornata, D. fraseri and D. nasuta feed mainly on surface-active insects. P. lepidopodus specializes on arthropods, especially mygalomorph spiders. Lialis burtonis and L. jicari feed on other reptiles, with over 95% of prey items being scincid lizards. Larger Lialis eat larger prey. Overall, Lialis is convergent with Australian elapid snakes in morphology (especially, dentition), thermal preferenda, prey types and ability to ingest large prey, but differs in foraging behavior. Aprasia may be morphologically and ecologically (diet, habitat) similar to typhlopid snakes. Pygopus and Delma are not ecologically similar to any Australian snakes, but may fill the niches occupied by insectivorous snakes on other continents.