Devonian terrestrial arthropods from Gondwana

The origin of the most diverse terrestrial animal group, Atelocerata (myriapods and hexapods), is obscured by an incomplete fossil record(1). Early (Silurian and Devonian) body fossils of terrestrial arthropods have been found only in Laurussia, with key sites in Britain and eastern North America(2-5). Although trace fossil assemblages indicate the presence of various arthropods on land in Australia in the Silurian Period(6), definite terrestrial arthropods have not been discovered in mid-Palaeozoic stages of the southern continents. Here I describe the first atelocerates from the Devonian stages of Gondwana; these are perhaps the earliest known remains of Australian land animals. The fossils comprise two closely related myriapod species of the genus Maldybulakia, first identified from Kazakhstan(7,8). They add substantially to our knowledge of the anatomy of this problematic arthropod, and illustrate the widespread distribution of parts of the Devonian terrestrial fauna. A dade including Maldybulakia is distinct within the Myriapoda at a high taxonomic level. The existence of Maldybulakia and the extinct classes Arthropleuridea and Kampecarida(9), with centipedes and millipedes, indicates the high class-level diversity of myriapods in the Devonian.