Luoxiongichthys hyperdorsalis was an early ginglymodian ray-finned fish, related to the ancestors of modern gars, living during the Middle Triassic (~244 million years ago) in coastal tropical marine waters covering what is now southwestern China.
About 15cm long (~6″), it had a large hump on its back shaped like a backwards shark fin. Its deep body was wider at the base, giving it a triangular shape when viewed from the front similar to some modern tropical fish – and suggesting it may have had a similar sort of ecology as a slow but highly maneuverable swimmer feeding on small seabed invertebrates.
References:
- Sun, Zuoyu, and Peigang Ni. “Revision of Kyphosichthys grandei Xu & Wu, 2012 from the Middle Triassic of Yunnan Province, South China: implications for phylogenetic interrelationships of ginglymodian fishes.” Journal of Systematic Palaeontology 16.1 (2018): 67-85. https://doi.org/10.1080/14772019.2016.1269049
- Wen, Wen, et al. “A new basal actinopterygian fish from the Anisian (Middle Triassic) of Luoping, Yunnan Province, southwest China.” Acta Palaeontologica Polonica 57.1 (2012): 149-160. https://doi.org/10.4202/app.2010.0089
- Wikipedia contributors. “Luoxiongichthys” Wikipedia, 11 Oct. 2023, https://en.wikipedia.org/wiki/Luoxiongichthys