FTIR characterization of Devonian (Spongiophyton Kräusel and Palaeostigma Kräusel & Dolianiti) and Permian (?Cyclostigma Dolianiti) fossil cuticles, Brazil

MATSUMURA, W.; IANNUZZI, R.; BALZARETTI, N.M.; DI PASQUO, M.M.; TURBINO, B.; SOUZA, PAULO ALVES

La Plata

Simposio; XVI Simposio Argentino de Paleobotánica y Palinología; 2015

universidad nacional de La Plata y Museo

Spectroscopy information (functional groups and semi-quantitative data) by Fourier transform infrared (FTIR) spectroscopy of Devonian (Spongiophyton and Palaeostigma) and Permian (?Cyclostigma brasiliensis) fossil cuticles is reported for the first time, in an attempt to identify spectroscopy patterns that would characterize these taxa. Both Devonian cuticles come from São Domingos Formation of Paraná Basin (Southern Brazil), and were obtained from stems. Permian cuticles comes from Pedra de Fogo Formation of Parnaíba Basin (northeastern Brazil), and was obtained from leaves. For comparative purposes, two living lycopsids (Selaginella and Lycopodiella) were also analyzed. Semi-quantitative data were performed through Fourier self-deconvolution obtained from 3000-2800 cm-1 (Al = aliphatic C-H stretching), 1800-1600 cm-1 (Ox = oxygen-containing groups and aromatic carbon), 1800-1700 cm-1 (Ox1 = contribution of carbonyl C=O), 1700-1600 cm-1 (Ox2 = aromatic carbon groups C=C), and 900-700 cm-1 (Ar = aromatic C-H out-of-plane bending) wavenumber regions. Infrared-derivated ratios (CH2/CH3, Al/Ox, Ox1/Ox2, C=O cont. and Ar/Al) led to a comparison of the structural features of analyzed material and showed significant differences among fossils remains. The results revealed that functional groups in 3000-2800 cm-1 and 1800-700 cm-1 wavenumber region are present in living and fossil materials, although their presence is more pronounced in fossils samples. CH2/CH3 ratio was higher in Spongiophyton sp. than Palaeostigma sp. and ?Cyclostigma brasiliensis. The chemical differences between Spongiophyton and Palaeostigma may support the taxonomic separation previously proposed. Semi-quantitative data indicate that Devonian cuticles showed higher oxidation and aromaticity in the organic matter than Permian one. [CNPq 141979/2011-9; PQ 309211/2013-1; PQ 300801/2012-2; 401769/2010-0]