Sturddlefish

The sturddlefish is a hybrid of the American paddlefish (Polyodon spathula) and the Russian sturgeon (Huso gueldenstaedtii), accidentally created by researchers in 2019 and announced in 2020. Obtaining living hybrids through breeding individuals from different families is unusual, especially given that the two species' last common ancestor lived over at least 141.4 million years ago based on mitochondrial DNA sequence. The hybrids were created accidentally during attempts to induce gynogenesis, a type of parthenogenic reproduction where a sperm cell must be present to trigger embryogenesis but does not genetically contribute to the offspring. Hundreds of hybrid fish were created, of which about two-thirds survived over one month, and about 100 survived for one year. As of July 2020, all living hybrid fish are in captivity at the research lab in Hungary. In 2024 a Hungarian research group, including some of the authors of the 2020 study, raised sturddlefish to 40 months old and measured the development of their reproductive organs to determine their potential fertility.