"Agnatha" II. Thelodonti

This handbook in the series created by Oskar Kuhn and managed since the 1970s by Professor Dr Hans-Peter Schultze is the definitive text on thelodonts, both articulated and isolated scales with references up to around 2006. These jawless agnathans are placed within a phylogenetic framework as members of the Craniata and Euvertebrata as close to the gnathostomes. They originate in the mid-late Ordovician and the last known species are now known from the late Devonian (mid-Famennian). The scales are biostratigraphically important and the basis for international Silurian and Devonian microvertebrate schemes. Thelodonts have been found in a range of palaeoenvironments from freshwater to marine. Susan Turner, April 2018.