A Silurian eurypterid (Arthropoda: Chelicerata) from China

Abstract

The oldest eurypterid from China is described as Hughmilleria wangi sp. nov., from the Xiaoxiyu Formation (Silurian: latest Llandovery) of Hunan Province. H. wangi is relatively similar to two species from North America, but differs in the development of epimera on the postabdomen, a slightly wider carapace, a styliform telson and the dimensions of the penultimate podomere of the paddle. The Llandovery age of the specimen substantially reduces the ghost range of the genus Hughmilleria. The exact phylogenetic relationship between the different species in Hughmilleria, the most basal genus in the pterygotoid clade, cannot be resolved because the plesiomorphic states within this clade are poorly known. The shapes of the telson and swimming paddle of the Chinese species suggest that it is more primitive than its North American relatives, which is in accord with its greater age.