Discriminating faunal assemblages and their palaeoecology based onmuseum collections: the Carboniferous Hurlet and Index limestonesof western Scotland

摘要

Historical collections of Scottish Carboniferous macrofossils stored at the British Geologi-cal Survey (BGS), Edinburgh include the sole remaining sources of palaeontological data fromnumerous localities. Exploratory numerical analyses of such collections from the Hurlet andIndex limestones of Ayrshire compare favourably with published qualitative assessments offaunal assemblages and palaeoenvironments; demonstrating that old collections can still beused in modern palaeoecological investigations. Macrofaunas from these formations comprisemainly brachiopods and molluscs and were collected from 67 localities that yielded 20 and 94samples from the Hurlet and Index limestones respectively. Limitations of the presence/absence data were partly overcome by consolidation and restriction of aspects of the data set.Seriation indicates the lithological and environmental gradients of taxa. Cluster analysisreveals groups of samples linked to lithofacies. Principal Components Analysis (PCA) ofdiversity data derived from the data set in terms of numbers of genera in higher taxa highlightsdifferences in gross taxonomic composition in terms of trophic structure, lithology andenvironment.