A research team led by Academician Zhu Min from the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP), Chinese Academy of Sciences, has described a new fossil lungfish from the Early Devonian of Zhaotong, Yunnan. The discovery, published in Current Biology, helps resolve a long-standing gap in the early evolutionary history of lungfishes.

Lungfishes are the closest living relatives of tetrapods. They first appeared in the Devonian and diversified rapidly, though only three genera survive today. The earliest confirmed lungfish is Diabolepis speratus from the Early Devonian of South China. Despite its importance, a clear morphological link between Diabolepis and more advanced lungfishes had been missing for decades.

The newly discovered species, Paleolophus yunnanensis, dates to about 410 million years ago and represents the first three-dimensionally preserved Pragian-aged lungfish skull known worldwide. Although only 25 mm long, the skull is exceptionally informative. High-resolution CT scanning reveals that Paleolophus combines primitive traits shared with Diabolepis—such as teeth on the upper lip and a prominent pineal region—with more advanced features characteristic of early true lungfishes.

The species also possesses a mix of unique adaptations, including an unusually enlarged nasal cavity and strongly developed jaw muscles, suggesting a diet that included hard-shelled prey. Of particular significance is the partially fused palatoquadrate–neurocranial region, which captures a transitional stage between the primitive “dual articulation” of early sarcopterygians and the autostylic skull typical of true lungfishes.

Using CT data and phylogenetic analyses, the researchers place Paleolophus at the base of “Eudipnoi,” a newly clarified grouping that includes all lungfishes except Diabolepis. Combined with precise geological age constraints, the study shows that the transition from Diabolepis to true lungfishes occurred within only about four million years (416–412 Ma), highlighting a rapid early evolutionary radiation.

Morphological similarities between Paleolophus and North American Early Devonian lungfishes also provide new biogeographical insights, suggesting that the South China and North American plates were connected or geographically close during this period.

Skull of Paleolophus yunnanensis 

Cranium evolution of early lungfishes

Phylogenetic and paleogeographic positions of Paleolophus yunnanensis 

Life reconstruction of a ~410 million years old lungfish from China and the associated biota, by Brian Choo