Archosaurs, sometimes called primordial archosaurs, originally meant "leading reptiles or ruling reptiles." This group includes familiar fossils and modern animals such as dinosaurs, pterosaurs, and crocodiles. Before the earliest dinosaurs appeared, various primitive archosaurs were already very abundant reptiles on Earth. The complex phylogenetic relationships among these groups have always been a hot topic of debate in paleontology. For a long time, it was believed that archosaurs, except for some crocodiles, were primarily terrestrial animals, until 2006 when researchers from the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences discovered early marine-type archosaur fossils in Panxian County, Guizhou Province. Recently, the same research group rediscovered similar fossils in Fuyuan County, Yunnan Province, and the findings were recently published online in the international journal *The Science of Nature* (formerly *Naturwissenschaften*).
The fossil, discovered in Middle Triassic limestone strata, represents a nearly complete skeleton of a novel semi-aquatic archosaur. This animal, approximately two meters long, was armored, with a thick neck, long tail, jagged teeth, and short, robust, webbed limbs, making it a ferocious predator in the prehistoric nearshore marine environment. Research indicates that this animal belongs to a very primitive archosaur group and is closely related to a rare group in North America. The fossil demonstrates that archosaurs, as a backbone of reptile evolution, began a semi-aquatic marine life very early in their history, further expanding our understanding of so-called "Mesozoic marine reptiles."
The newly discovered fossil has been named *Litorosuchus somnii*, meaning "crocodile-like animal on a beach in a dream." According to researcher Li Chun, the project leader, shortly after the fossil's discovery, he dreamt one night of a giant crocodile-like animal walking on the beach, hence the name.
Figure 1. Fossil specimen of Litorosuchus somnii (Photo provided by Li Chun)
Figure 2 “Prehistoric Crocodile in a Dream”: Reconstruction of the Dream Crocodile (Litorosuchus somnii) (Illustrated by Chen Yu)
