Novel pterygotid sea scorpions from the Silurian and Devonian of Gondwana

Abstract

Sea scorpions (eurypterids) are a group of extinct aquatic chelicerates that have a fossil record spanning the Ordovician through to the end Permian extinction. Due to their size and preservational potential, eurypterids have been well-documented in European and North American deposits, with less evidence from Gondwana. There is particularly limited evidence of the group from the Australian fossil record. To rectify this, we report new examples of pterygotid eurypterids from the late Silurian Wallace Shale and Early Devonian Merrimerriwa Formation, Mulga Downs Group in New South Wales. These specimens are assigned to Pterygotus sp. (Wallace Shale) and Jaekelopterus c.f. rhenaniae (Merrimerriwa Formation, Mulga Downs Group). The material is used to explore the extensive distribution and dispersal of these large, pelagic eurypterids and consider the position of the animals in their respective paleoecosystems. We conclude that these new records evidence the diversity of larger arthropods in Australian deposits and that ongoing documentation of these rare fossils is required to further understand the Paleozoic of Australia.