How do amphibians reproduce without a free-swimming larval stage?

Many amphibians have evolved to bypass the traditional free-swimming larval stage through a process known as direct development. In this mode of reproduction, the entire larval phase occurs within the egg membranes, allowing the young to hatch as miniature versions of the adult, or "froglets".12

This evolutionary strategy is found across many families of anurans, as well as in many lungless salamanders and some caecilians. Common methods include:2

• Terrestrial Nesting: Species such as those in the genus Eleutherodactylus deposit eggs in moist terrestrial environments like leaf litter, moss, or under logs, where they develop and hatch directly into small adults.1
• Parental Brooding: Some species carry eggs on their bodies to protect them from desiccation. For example, certain marsupial frogs develop their young within a dorsal pouch, while others carry them in depressions on their backs.1
• Viviparity: Some amphibians have evolved live birth, where embryos develop internally within the female's reproductive tract, bypassing the need for an external larval stage entirely.12

These adaptations allow amphibians to sever their ties with aquatic environments, enabling them to complete their life cycles in diverse habitats.12