New insights on the morphology and phylogeny of the Chinese dolichopterid eurypterid Malongia (Eurypterida, Dolichopteridae)

A recently recovered slab of siltstone preserving two individuals of Malongia mirabilis Wang et al., 2022 is described from the Early Devonian Xitun Formation in Yunnan Province, south-western China. This material reveals a suite of morphological features that were not documented in the original description of the species. Using these newly-recognised morphological characters, we revise the morphological character matrix and re-assess the phylogenetic affinity of M. mirabilis . Our phylogenetic analyses reveal that Malongia occurs in a polytomy with Dolichopterus and the clade comprising Ruedemannipterus and Clarkeipterus . The new material, therefore, improves our knowledge of the morphology of this poorly known Chinese dolichopterid and provides new evidence for evaluating the evolutionary history of Dolichopteridae on the South China Block.