Fossil fish rewrites otophysan evolution history

October 05, 2025 由 AI 报道

A tiny fossil fish discovered in southwestern Alberta is the oldest North American otophysan, offering new insights into the evolution of freshwater fish species. Named Acronichthys maccognoi, the 4 cm specimen from the Late Cretaceous period suggests otophysans transitioned from marine to freshwater environments at least twice. The find, detailed in a study published on October 2 in Science, challenges previous understandings of their global spread.