Rare 450-million-year-old sea scorpion fossil discovered in China

The species most likely thrived in deep water at depths of several hundred meters. The study highlights this newly described species as a rare find, as only 12 Ordovician eurypterids have been found and documented globally. According to the research, eurypterids are an extinct group of Paleozoic chelicerate arthropods.

This unusual fossil discovery could shed light on the early evolution of eurypterid species that, million years ago, occupied parts of the Gondwana supercontinent. The eurypterids appeared for the first time during the Ordovician geological period. The official statement highlights that they “attained their maximum diversity during the late Silurian and early Devonian and became extinct at the end of Permian.” 

Due to their unusual morphology and ecological diversity, eurypterids occupied almost every place on Earth, from marine to freshwater and even terrestrial environments. As a result, scientists believe they are critical to understanding the "transition of ecological environments in the Paleozoic."

This site also yielded fossils of other marine life that once thrived in the deep sea, such as sponges. "The specimen is preserved, together with diverse sponges, graptolites and occasional nautiloids, in a 10 m thick shale of marine deep-water setting," noted the study. 

The results have been published in the Journal of Paleontology.

Study abstract:

An early form of eurypterids (Chelicerata), Archopterus anjiensis n. gen. n. sp., is described from the uppermost Ordovician Wenchang Formation of Anji County, Zhejiang Province, South China. It is the earliest record of eurypterids in China and likely the oldest representative of the Adelophthalmidae. The species, represented by a single specimen, is diagnosed by a ventrally preserved prosoma with a parabolic carapace, Hughmilleria-type prosomal appendages, a short vase-shaped metastoma, and a three-segmented type A (female) genital appendage. The specimen is preserved, together with diverse sponges, graptolites and occasional nautiloids, in a 10 m thick shale of marine deep-water setting. This finding extends the stratigraphic range of adelophthalmids from the previously recorded early Silurian into the Late Ordovician (some 10 million years older) and supports an earlier cryptic phase of eurypterid evolution in Gondwana.