Modern amphibians cannot tolerate salt water. Frogs desiccate. Salamanders osmotically collapse. The few exceptions — crab-eating frogs, brackish-water newts — survive through specialized physiology that most amphibian lineages never evolved. Amphibians are freshwater animals. Everyone knows this.
Trematosaurids didn't. Their fossils turn up in marine deposits worldwide, consistently, across multiple genera and millions of years. They were apparently unbothered by salt water.
A new paper revising the Western Australian trematosaurid Erythrobatrachus noonkanbahensis (Journal of Vertebrate Paleontology, 2026) confirms that the Blina shale near Broome held two distinct marine temnospondyls living side by side: Erythrobatrachus with a broad, robust skull (top predator), and Aphaneramma with a long, thin snout (fish catcher). Both had skulls around 40 centimeters long. Same habitat, different prey. A marine amphibian community, not a lone anomaly.
The fossils were collected in the 1960s, dispersed to museums in Australia and the United States, and some were lost for fifty years. A high-quality plaster cast at the Western Australian Museum preserved the critical morphology, and one missing fragment was recovered from UC Berkeley's collection. The rediscovery revealed that what was thought to be one species was actually two — distinguished by skull proportions visible only when all the scattered material was reassembled.
The timing matters. These rocks are less than 1 million years after the Permian extinction — the Great Dying that killed 90% of marine species. Within a million years, marine amphibians had diversified into multiple species occupying different ecological niches in the same environment. The recovery was fast.
And global. Aphaneramma fossils of equivalent age appear in Svalbard (Arctic), Russia, Pakistan, Madagascar, and now Australia. This is not a local recovery. It is a cosmopolitan radiation — a single lineage dispersing across the entire Tethys and Panthalassic margins within the earliest Triassic. For animals that should not be able to tolerate salt water, they were remarkably good at crossing oceans.
The epistemological note: we know modern amphibians as freshwater obligates. We generalize this to the clade. But “amphibian” as a functional category was broader 250 million years ago than it is today. The modern survivors are a biased sample — the lineages that won the freshwater niche long-term. The marine experiment was large, global, diverse, and lasted millions of years. It just didn't lead to anything alive today, so it became invisible to the generalization.
The fossils were in museums for fifty years. The two species were mixed together in the same collection. The marine amphibian community existed in the data before anyone assembled it into a community. The pattern was present. The classification framework — one species, freshwater ancestors — prevented it from being seen.
Revision of the trematosaurid Erythrobatrachus noonkanbahensis, Journal of Vertebrate Paleontology (2026). Fossils from Blina shale, Western Australia.