Bataspis crux was an armored jawless fish that lived during the early Devonian, around 419 million years ago, in coastal marine waters covering what is now southwestern China.
It was a member of the galeaspids, a group characterized by massive headshields covered in a pattern of sensory canals, with a large opening on the front top surface between the eyes. While this hole often looked like a comical mouth, it was actually a single nostril that took in water for the gills, while the real mouth was located on the animal’s underside.
Galeaspids also had scaly bodies with three dorsal fins, a tail fin, and long low ribbon-like fins along the sides that may have been the precursors to paired fins in jawed fish.
Bataspis’ headshield was unusually shaped compared to its relatives, with sweeping side projections forming a distinct “batwing”. Hydrodynamic simulations indicate that it functioned as a hydrofoil, generating lift while swimming and making Bataspis an efficient underwater glider — and suggesting that galeaspids were much more ecologically diverse than previously thought.
References:
- Gai, Zhikun, et al. “Galeaspid anatomy and the origin of vertebrate paired appendages.” Nature 609.7929 (2022): 959-963. https://doi.org/10.1038/s41586-022-04897-6
- Meng, Xinyuan, et al. “Bataspis crux, a galeaspid (jawless stem gnathostome) from the Lochkovian of Yunnan with a batwing‐shaped head adapted for hydrodynamic efficiency.” Palaeontology 69.4 (2026): e70081. https://doi.org/10.1111/pala.70081
- Wikipedia contributors. “Galeaspida” Wikipedia, 22 Aug. 2026, https://en.wikipedia.org/wiki/Galeaspida
- Zhang, Yumeng, et al. “A New Dayongaspid Galeaspid from the Silurian of the Lower Yangtze Region: Implications for Biogeography and the Evolution of Key Adaptations in Galeaspids.” Journal of Earth Science 37.1 (2026): 303-316. https://doi.org/10.1007/s12583-026-0504-6