It’s easy to study the sexual characteristics of modern-day fish. But for the ones long extinct, it’s a little more difficult. Take the Venusichthys comptus, a primitive type of ray-finned fish fish now no longer inhabiting the Earth. It and others of its kind were lost during the end of the Permian Period, but some of its relatives still exist today.
For that reason, researchers with the Chinese Academy of Sciences have been interested in figuring out the sexual characteristics of the long-extinct fish for some time. And thanks to a recent fossil find, they have been able to do just that.
About 30 well-preserved specimens of the fish were uncovered in the eastern Yunnan Province in China not too long ago. The scientists were able to evaluate those to find that about a third of them had hook-like contact organs near their anal fins, and were likely males. Some secondary sexual characteristics emerged as well, in the form of pointed tubercles on the skulls and dorsal fins.