Chimaeras – an ancient group of cartilaginous fishes closely related to sharks, skates, and rays – swim by flapping their pectoral fins in a manner resembling bird flight. This unique locomotory mode, termed flapping flight, induces an undulatory wave that travels from the leading edge to the trailing edge of their pectoral fins. A manoeuvrability-efficiency trade-off exists for pectoral fin swimmers, with flappers and oscillators being more efficient and less manoeuvrable than rowers and undulators. Chimaeras might mitigate the effects of this trade-off by combining efficient flapping and manoeuvrable undulating. I designed a fin-flapping robot and several artificial fins of varying fin ray diameter, fin ray packing density, and speciesaccurate shape to determine how morphology (fin rays and shape) influences pectoral fin dynamics (movement, force production, and fluid flow structures). Extensive research has been conducted on the morphological adaptations that mediate swimming dynamics in other fishes; however, chimaera flapping flight is understudied. Point tracking software was used to examine the effects of fin ray diameter and packing density on pectoral fin kinematics. Two-dimensional geometric morphometrics was used to quantify shape variation in the pectoral fins of 17 species from all three chimaera families. A force-torque sensor and particle image velocimetry were used to measure forces and visualize flows generated by artificial chimaera pectoral fins. Fin ray diameter, fin ray packing density, and fin shape all impact dynamics. Understanding the consequences of morphological variation in chimaera pectoral fins helps untangle the mechanical trade-offs of flapping flight and elucidate how swimming demands among habitats may have contributed to chimaera diversification. The distinct swimming requirements between deep, calm ocean waters and shallow, wave-swept nearshore environments may shape chimaera pectoral fins. Additionally, my research could lead to the design of novel underwater vehicle propulsors. Man-made propellers are not particularly manoeuvrable and disturb their surroundings; propulsors inspired by chimaeras may be able to avoid these drawbacks while maintaining efficiency.