The helicinid land snail Pleuropoma extincta (Odhner, 1917) as an environmental indicator in archaeology

Land snails have long been used as palaeoenvironmental indicators in some parts of the world, but in Australia they have received little attention. Here we present new data on the geographical distribution and ecological characteristics of the helicinid Pleuropoma extincta (Odhner, 1917). The species is confined to the limestone outcrops of the Chillagoe Formation where it occurs abundantly both as living populations on the limestone rock and associated vegetation, and as dead shells in the litter deposits. After analysing >1,100 modern snail shells from 24 collection localities (from two major limestone regions within the formation), we argue that the sensitivity of shell growth (measured as size-correlated differences in whorl counts) to environmental moisture variation in P. extincta makes this species particularly suitable for palaeoenvironmental research. Differences in whorl counts of sub-fossil P. extincta shells from archaeological excavations at Hay Cave, in tropical northeastern Australia, are then investigated. We conclude with observations about the implications of the land snail shell sequence for the nature and timing of changes in rainfall levels during the last 19,000 years in north Queensland, and how these changes compare and contrast with existing palynological trends for the Atherton Tableland nearby.

Memoirs of the Queensland Museum

Memoirs of the Queensland Museum

46

0079-8835

N/A

2

30