A new genus and species of eurypterid (Chelicerata, Eurypterida) from the Lower Devonian Xiaxishancun Formation of Yunnan, southwestern China

Eurypterids constituted an important component of Paleozoic marine ecosystems, but their fossil record has been mainly reported from North America and Europe, and the evolution of this group in other regions such as East Asia remains poorly understood. A new eurypterid, Malongia mirabilis nov. gen., nov. sp., is described from the Lower Devonian (Lochkovian) Xiaxishancun Formation of Qujing, Yunnan, southwestern China. The holotype shows a ventral prosoma with appendages II–VI and part of the opisthosoma. The characters indicating a dolichopterid affinity of the new taxon include: metastoma anterior cordate and basally truncated; appendage III bearing multiple enlarged spines; appendage V nonspiniferous; long appendage VI with expanded distal podomere and narrow triangular VI-7a; subrhomboidal coxa of appendage VI with a rounded principal tooth. Malongia nov. gen. is the fourth genus described within the Dolichopteridae Kjellesvig-Waering and Størmer, 1952, other members of which are Dolichopterus Hall, 1859, Clarkeipterus Kjellesvig-Waering, 1966, and Ruedemannipterus Kjellesvig-Waering, 1966; it represents the only record of this family in South China.