Why in news?
Palaeontologists in China have described a new species of the ancient fish genus Whiteia based on two fossil specimens from the Early Triassic period. The discovery, announced in October 2025, extends the geographical range of these prehistoric coelacanths to Asia and sheds new light on the diversity of these so‑called “living fossils.”
Background
Coelacanths are lobe‑finned fish belonging to the order Coelacanthiformes. They first appeared around 420 million years ago during the Devonian period and flourished in ancient seas and rivers. For a long time, scientists believed that coelacanths went extinct along with the dinosaurs about 66 million years ago. That view changed in 1938 when a living coelacanth was unexpectedly caught off the South African coast, earning them the nickname “living fossils.” Today, two extant species survive: the West Indian Ocean coelacanth (Latimeria chalumnae) and the Indonesian coelacanth (Latimeria menadoensis).
Distinctive features
- Limb‑like fins: Coelacanths possess fleshy, paired fins supported by bone structures. The fins move in a synchronised pattern resembling the movement of limbs in four‑legged animals, highlighting the evolutionary link between lobe‑finned fishes and early tetrapods.
- Electrosensory organ: A specialised sensory organ in their snout, called the rostral organ, allows coelacanths to detect low‑frequency electrical signals and to “see” in the dark depths where they live.
- Unique skull hinge: A joint in the skull enables the front portion of the braincase to swing upward, expanding the gape of the mouth and aiding in the capture of prey.
- Size and habitat: Living coelacanths inhabit deep marine waters, often at depths of 200–700 metres. They can grow nearly two metres long and have a slow metabolism, contributing to their longevity.
Significance of the discovery
- Expanding fossil record: The newly described species, Whiteia anniae, shows that coelacanths were more widespread in Early Triassic ecosystems than previously known. Its discovery in China fills a geographic gap and suggests that coelacanths diversified rapidly after the Permian–Triassic mass extinction.
- Evolutionary insights: Studies of coelacanth fossils, combined with genetic research on living species, help scientists understand how vertebrates transitioned from water to land and how certain traits—such as limb bones—evolved.
Conclusion
Coelacanths remain an emblematic group for evolutionary biology. The discovery of new fossil species like Whiteia anniae underscores how much we still have to learn about the diversity and resilience of life on Earth across geological time scales.
Source: Sci.News