A Revision of the Arcitalitridae Myers & Lowry, 2022 (Amphipoda, Talitroidea): Establishment of New Families and Observations on the Origin and Evolution of Simplidactylate Landhoppers

The morphological adaptations of simplidactylate landhoppers to life out of standing water primarily involve changes in gill and pleopod structure. Recognition of significant and consistent differences in these structures within the simplidactylate Arcitalitridae has resulted in the establishment of three new families that are described here. Four families are now recognised in the previously diagnosed Arcitalitridae, a family that comprised all known simplidactylate landhoppers. They are thought to have originated during the upper Jurassic or lower Cretaceous in Gondwana and then been transported during the Cretaceous to their present distributions in Africa, Australia and New Zealand. This vicariance hypothesis is supported by their extant endemic distributions in former Gondwanan landmasses and by the lack of a long-distance dispersal phase in their life history. The relatively low diversity of simplidactylate landhoppers in the world today is attributed to high extinction rates rather than to low origination rates.