New basal Namurian (Upper Carboniferous) fishes and crustaceans found near Glasgow

Abstract

I report here a recent discovery of new species of sharks, together with the most complete and best-preserved Carboniferous shark known, in Bearsden near Glasgow. Sharks of this age are significant because of their high diversification rate during the Carboniferous. This, coupled with their poor fossil record, has led to “almost as many classifications of Palaeozoic chondrichthyan fish as there are taxa in this group represented by adequate specimens”¹. The new shark discoveries also throw considerable morphological light on relatively fragmentary material collected during the past few years from the Upper Mississippian (Lower Namurian) of Montana². The fish found also include 11 new palaeoniscid (early ray-finned) fishes which represent the first known British Namurian marine species. The site has also yielded a crustacean assemblage which is probably the best preserved from Europe or even the Northern Hemisphere. The only comparable crustacean fauna, from beds of Wesphalian age at Mazon Creek in Illinois, is larger but is mainly preserved as moulds whereas the Bearsden material preserves the cuticle intact. The first (and last) major discovery of a substantial vertebrate and crustacean marine fauna from the British Carboniferous was made in 1879 when the Glencartholm site (Dumfries and Galloway) was found by Macconochie of the Scottish Geological Survey³ in the Lower Carboniferous, Upper Border Group (Upper Dinantian, Asbian).