Palaeontologia Electronica http://palaeo-electronica.org EARLY EOCENE DISPERSED CUTICLES AND MANGROVE TO RAINFOREST VEGETATION AT STRAHAN-REGATTA POINT, TASMANIA Mike Pole Mike Pole. Queensland Herbarium, Toowong, Qld 4066, Australia.
[email protected] ABSTRACT Early Eocene plant-fossil assemblages (mostly of dispersed cuticle) from Strahan- Regatta Point, Tasmania, Australia, record evidence of mesothermal rainforest (mean annual temperatures between 12 and 20ºC) and mangrove vegetation surrounding an estuary, which grew close to the polar circle. Plant taxa represented by cuticle include: Bowenia (Cycadales), conifers, including Acmopyle, Agathis, Araucaria, Dacrycarpus, Libocedrus, Prumnopitys, and a gnetalean. Fifty- five taxa of angiosperms are recogn- ised from cuticle, including Winteraceae, 11 Lauraceae (including an unusual toothed species) and seven Proteaceae as well as Gymnostoma, Aquifoliaceae, and Rhipogo- naceae. There is also a Rhizophoraceae, which is interpreted as another mangrove, in addition to the mangrove palm Nypa, which has been described previously. In an Aus- tralasian context the absence of Myrtaceae is notable. Multivariate analysis of the fossil distribution suggests that a significant amount of the variation can be attributed to whether they accumulated in the mangrove mud (or associated tidal sand flat) or in a freshwater facies. KEY WORDS: Early Eocene, cuticle, stomata, mangrove, biodiversity, paleoclimate INTRODUCTION al. 1999; Zachos et al. 2001, 2005). Today the world is also undergoing profound warming due to The Early Eocene includes two periods of glo- anthropogenic greenhouse gases (Intergovern- bally warm temperatures where thermophilic vege- mental Panel on Climate Change 2007) and under- tation (among other biota) extended its range standing the effects this will have on the biota and significantly towards the poles; these were the local climates has become a key research goal.