Wang, Braddy, Botting & Zhang, 2023
Artwork: Dinghua Yang.
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.
Subphylum Chelicerata Heymons, Reference Heymons1901
Order Eurypterida Burmeister, Reference Burmeister1843
Suborder Eurypterina Burmeister, Reference Burmeister1843
Family Adelophthalmidae Tollerton, Reference Tollerton1989
Genus Archopterus new genus
Etymology: Genus name from the Latin prefix arch-, meaning “ancient,” and -opterus, a common suffix for eurypterids, meaning “wing.”
Archopterus anjiensis n. gen. n. sp.
Holotype: NIGP 164906, Nanjing Institute of Geology and Palaeontology, CAS, China.
Diagnosis: Adelophthalmid with a parabolic carapace, Hughmilleria-type prosomal appendages, vase-shaped metastoma, and three-segmented type A (female) genital appendage.
Occurrence: Hirnantian (Metabolograptus persculptus Biozone) of the Wenchang Formation of Tianfucun, Anji County, Zhejiang Province, South China.
Etymology: The species is named after Anji County, where the type specimen was discovered.
Han Wang, Simon J. Braddy, Joseph Botting and Yuandong Zhang. 2023. The First Documentation of An Ordovician eurypterid (Chelicerata) from China. Journal of Paleontology. First View. DOI: 10.1017/jpa.2023.21