A team of researchers from the Nanjing Institute of Geology and Paleontology of the Chinese Academy of Sciences (NIGPAS) and their collaborators from the U.K. have recently published a study in the Journal of Paleontology, unveiling the discovery of a new species of eurypterid. Eurypterids, commonly referred to as sea scorpions, are an important group of extinct arthropods belonging to the Chelicerata class. The newly described species, named Archopterus anjiensis, was found in the Anji Biota of Zhejiang Province, South China. This finding not only marks the first confirmed occurrence of an Ordovician eurypterid in China but also represents the oldest eurypterid species ever discovered in the country. The study sheds light on the early evolution of eurypterids in Gondwana and provides valuable insights into the ecological transition during the Paleozoic era. Eurypterids originated in the Ordovician period, reached their peak diversity in the late Silurian and early Devonian periods, and eventually became extinct at the end of the Permian period. These fascinating creatures displayed peculiar morphologies and inhabited various environments, including marine, freshwater, and even terrestrial habitats. Given the scarcity of Ordovician eurypterid fossils worldwide, with only 12 known species, any new discovery in this field holds immense significance for understanding their early evolutionary history.
A recent study published in the Journal of Paleontology has unveiled a remarkable discovery of a rare Ordovician eurypterid in Zhejiang Province's Anji County. The newly described species, Archopterus anjiensis, exhibits distinct characteristics such as a parabolic carapace, Hughmilleria-type prosomal appendages, a vase-shaped metastoma, and a three-segmented type A (female) genital appendage measuring approximately 15 cm in length. Wang Han, the study's first author, shared these intriguing details.
Archopterus anjiensis was found in association with diverse sponges within a deep-water environment, several hundred meters below the surface. This finding, coupled with the existence of other Ordovician eurypterids from normal marine environments, suggests that certain early eurypterids preferred deeper waters compared to their post-Ordovician counterparts.
Furthermore, the discovery of Archopterus anjiensis establishes it as the oldest known adelophthalmid, expanding the stratigraphic range of this family to the Late Ordovician by approximately 10 million years. Consequently, Adelophthalmidae emerges as the longest-surviving eurypterid family, spanning from the Ordovician to the Permian. This finding also indicates that adelophthalmids have occupied the broadest range of habitats among all eurypterid groups.
The rarity of this Ordovician sea scorpion from Zhejiang Province, combined with the continuous unearthing of eurypterid fossils in China, underscores the immense potential for further exploration of eurypterids in Gondwana regions during the Paleozoic era.
Source: Chinese Academy of Sciences