2026/07/01 by Xinyuan Meng, Humberto G. Ferrón, Davide Pisani +2 · 1 voice
Earth and Planetary Sciences · Environmental Science · #Paleontology and Evolutionary Biology #Paleontology and Stratigraphy of Fossils #Ichthyology and Marine Biology #Lift (data mining) #Margin (machine learning) #Phylogenetic tree #Eccentricity (behavior) #Vertebrate #Convergent evolution #Turtle (robot)
paper · doi:10.1111/pala.70081
openalex publication_date 2026/07/01 · openalex created_date 2026/08/05 · openalex updated_date 2026/08/05
Abstract Galeaspids are an extinct group of jawless fishes from the Silurian–Devonian of China and northern Vietnam that are key to understanding the origin of vertebrate anatomical innovations. A new eugaleaspid, Bataspis crux gen. et. sp. nov., is described based on fossil material from the Lochkovian (Early Devonian) Xishancun Formation of Qujing, Yunnan, China. Bataspis crux possesses a suite of unusual features, especially its bat‐wing‐like cornual processes that are seamlessly integrated with a brim‐like rostral margin without a rostral process, constituting a unique morphology for galeaspids. Maximum parsimony, maximum likelihood and Bayesian phylogenetic inference all support membership in the family Tridensaspidae. We employed computational fluid dynamics to infer the hydrodynamic properties of the headshield of B. crux . Our analysis reveals that this species achieves an exceptionally high lift‐to‐drag ratio; the highest recorded among known galeaspids. This remarkable efficiency stems from its low drag across various angles of attack, coupled with passive lift generation through the exploitation of the Bernoulli effect by the airfoil cross‐section of the cornual processes. This suggests that the species was an effective gliding cruiser, outperforming not only galeaspids but also other stem gnathostomes, such as osteostracans and pteraspidomorphs. These results provide new insights into our understanding of the evolution of Tridensaspidae, the ecological habits of stem gnathostomes and convergence in the evolutionary assembly of the gnathostome bodyplan.