First filter feeding in the Early Triassic: cranial morphological convergence between Hupehsuchus and baleen whales ...

• Main Authors: Fang, Zi-Chen, Li, Jiang-Li, Yan, Chun-Bo, Zou, Ya-Rui, Tian, Li, Zhao, Bi, Benton, Michael J., Cheng, Long, Lai, Xu-Long
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: figshare 2024
• Subjects: Evolutionary Biology; FOS: Biological sciences; Environmental Sciences not elsewhere classified; Ecology; Biological Sciences not elsewhere classified; Marine Biology; Inorganic Chemistry; FOS: Chemical sciences; Science Policy; baleen whales
• Online Access: https://dx.doi.org/10.6084/m9.figshare.c.6779025; https://springernature.figshare.com/collections/First_filter_feeding_in_the_Early_Triassic_cranial_morphological_convergence_between_Hupehsuchus_and_baleen_whales/6779025

Abstract Modern baleen whales are unique as large-sized filter feeders, but their roles were replicated much earlier by diverse marine reptiles of the Mesozoic. Here, we investigate convergence in skull morphology between modern baleen whales and one of the earliest marine reptiles, the basal ichthyosauromorph Hupehsuchus nanchangensis, from the Early Triassic, a time of rapid recovery of life following profound mass extinction. Two new specimens reveal the skull morphology especially in dorsal view. The snout of Hupehsuchus is highly convergent with modern baleen whales, as shown in a morphometric analysis including 130 modern aquatic amniotes. Convergences in the snout include the unfused upper jaw, specialized intermediate space in the divided premaxilla and grooves around the labial margin. Hupehsuchus had enlarged its buccal cavity to enable efficient filter feeding and probably used soft tissues like baleen to expel the water from the oral cavity. Coordinated with the rigid trunk and pachyostotic ribs ...