A multivariate taxonomic analysis of the Late Carboniferous vertebrate ichnofauna of Alveley, southern Shropshire, UK

A diverse Late Carboniferous (Westphalian D; Moscovian) vertebrate ichnofaunal assemblage from the Alveley Member (Salop Formation, Warwickshire Group) of Alveley, southern Shropshire, UK, is a significant example of an early, transitional tetrapod community. Positive tetrapod footprint casts (convex hyporeliefs) within fine- and medium-grained sandstone red-beds were formed subaqueously in an alluvial floodplain setting. A statistical analysis of this material, the first using multivariate techniques on Late Palaeozoic trackways, has been undertaken to determine the ichnospecific diversity and morphological variation within the ichno-assemblage. Nine ichnotaxa have been identified, following a study of more than 200 trackways. These include the amniote ichnogenera Dimetropus Romer and Price, 1940, Ichniotherium Pohlig, 1885 and Hyloidichnus Gilmore, 1927, but there is a dominance of trackways of the ichnogenus Limnopus Marsh, 1894, which represent stem-lissamphibian 'temnospondyls'. Following statistical analysis, the ichnogenera Limnopus and Batrachichnus are subsumed as ichnosubgenera under the senior available name Limnopus. The Alveley ichnofaunal assemblage provides significant range extensions for a number of amniote and stem-lissamphibian trackmakers from the latest Carboniferous or Permian down into the mid-Late Carboniferous. It also marks a key transitional stage in the evolution of tetrapod communities, from the 'amphibian' grade assemblages of the Carboniferous to the more terrestrial, amniote-dominated communities of the Early Permian.