Three New Live‑Bearing Tree Toads Discovered in Tanzania — They Skip the Tadpole Stage

Three new tree toads discovered in Tanzania reproduce without tadpoles

Most people learn that frogs and toads start life as eggs, become tadpoles and then metamorphose into adults. While that pattern holds for the majority of the world's nearly 8,000 frog species, a small group of amphibians has evolved a very different strategy. Members of the genus Nectophrynoides — commonly called tree toads — give birth to fully formed, miniature "toadlets," bypassing both eggs and free‑swimming tadpole stages.

New species and how they were confirmed

In a paper published in Vertebrate Zoology, researchers describe three additional species of Nectophrynoides from the forests of Tanzania that also reproduce via live birth. To confirm these discoveries, the team combined detailed morphological study of hundreds of preserved specimens with DNA extracted from century‑old museum material — a technique known as museuomics. These genetic samples included specimens collected in 1905 by German researcher Gustav Tornier, which had been archived at Berlin’s Museum für Naturkunde for more than a century.

“It’s common knowledge that frogs grow from tadpoles — it’s one of the classic metamorphosis paradigms in biology,” said Mark Scherz, co‑author and herpetology curator at the Natural History Museum Denmark. “But [frogs] actually have a wide variety of reproductive modes, many of which don’t closely resemble that famous story.”

By comparing DNA from historic specimens with modern populations and carefully re‑examining morphological traits, the researchers were able to match old museum samples to living populations and confidently describe three previously unrecognized species.

Why live birth evolved — and why it matters

Researchers believe live birth evolved in these tree toads as an adaptation to life far from reliable bodies of water. In mountainous or forested habitats where ponds and streams are scarce or temporary, producing terrestrial young that do not require an aquatic larval stage can be advantageous. However, this specialization can also increase extinction risk when habitats are lost.

The newly described species live in the Eastern Arc Mountains of Tanzania, one of the world’s richest biodiversity hotspots. That region is under severe pressure from deforestation and climate change, which imperil many endemic species. Several Nectophrynoides species are already critically threatened: Nectophrynoides asperginis is extinct in the wild, and Nectophrynoides poyntonii has not been observed since 2003.

Conservation implications

Finding three additional live‑bearing tree toads expands our understanding of amphibian reproductive diversity but also underscores the fragile status of these frogs. The authors call for targeted conservation actions — habitat protection, monitoring, and, where appropriate, captive‑breeding programs — to ensure these unusual toads can continue producing future generations of toadlets.

Key takeaways: three new Nectophrynoides species were identified in Tanzania using museuomics and morphological analysis; live birth likely reflects adaptation to terrestrial habitats; habitat loss puts these specialized frogs at high risk.