Neopterygian fish with secondary sexual characteristics found from the Middle Triassic of China

Secondary sexual characteristics are features that appear at sexual maturity and distinguish the two sexes of a species. Studies of secondary sexual characteristics in a species are vital for fully understanding its behavior, reproduction, and evolution. Secondary sexual characteristics are easily observed and studied in living animals, but the situation is rather more complicated in extinct animals, primarily due to inadequacies of sample size or the fragmentary nature of fossil remains. —> Read More