A new species of fossil lamprey (Petromyzontida: Petromyzontiformes) from Hebei, China

A subclass of Mesozoic lamprey from Chengde, Hebei, China, Caeruleum miraculum gen. et sp. nov. is described. This new species has typical characteristics of another subclass of lamprey including an eel-like slender body, no paired appendages, absent jaws, round at anterior and laterally flat at posterior, and seven gill foramina, with anterior dorsal fin, posterior dorsal fin, and caudal fin. In addition, the total length of this species is between 240 mm (Table 1)-462 mm (Figure 4), which is 16.47 times the body depth, 4.01 times the head length, and 4.24 times the caudal length. Its body size is huge and very close to modern lampreys. This article briefly compared this species with the known Mesomyzon mengae. The discovery of these new fossils provides new evidence to study the evolution of Chinese lampreys during the Mesozoic and to explore the origin of modern lampreys.