Biological aspects of the adaptive radiation of Australasian pythons (Serpentes: Boidae)

Analysis of specimens representing 13 species of Australasian pythons showed that females generally exceed males in average adult body size and mature at a higher proportion of mean adult snout-vent length (SVL). Reproductive biology is conservative, with all taxa apparently oviparous and with maternal attendance at the nest. Female reproductive cycles are strongly seasonal but differ among species and areas. Data suggest a generally low reproductive frequency. Mean clutch sizes of 5-16 eggs were recorded, with hatchling size highly correlated with mean adult SVL interspecifically and with incubation period dependent upon hatchling size. Australasian pythons consume a wide range of vertebrates, with a shift from reptiles to mammals in larger species and in larger individuals within a species. Overall, the adaptive radiation of pythons in Australia has involved retention of many primitive features, but the invasion of an arid continent has favored greater utilization of reptilian prey and (consequently?) evolution of smaller body size. -from Authors