Thousands of silicified wood fragments were recently collected from the middle Cenomanian of Vienne in western France at less than 10 km away from a historical locality where in 1870 the French geologist Alphonse Le Touzé de Longuemar reported silicified wood. The plant assemblage is very diverse, and includes several species of ferns, conifers, and angiosperms. We describe and discuss the systematic affinities of a new vesselless angiosperm. Many of its characters are shared by extant and fossil Winteraceae. Nevertheless, the absence of uniseriate rays makes the anatomy of these specimens unique. Its combination of characters justifies the establishment of a new genus of vesselless fossil angiosperm wood of uncertain affinity, Sherwinoxylon gen. nov.
Premise of research. Fossil leaves are commonly used as proxies for continental paleoclimate reconstruction. In particular, temperature and precipitation variables are derived from taxon-free methods using only fossil leaf morphology. Although there is a general relationship between leaf form and climate at a global scale, possible differences between and within angiosperm families remain little explored.Methodology. In this article, we analyzed the influence of phylogenetic relatedness and climate on leaf architecture in 30 species of Cinnamomum (Lauraceae). Nineteen morphological features were selected and documented on the basis of digitized herbarium specimens. Repeatability was measured for all traits. Phylogenetic signal was measured using Blomberg's K. The relationship between morphological variables and climatic variables was investigated using univariate and multivariate statistical approaches.Pivotal results. Our analysis revealed that phylogenetic signal was mainly observed in traits linked to the venation pattern. Size-and shape-related variables are more influenced by climatic parameters than by historical constraints. Cinnamomum leaf morphology is significantly correlated with mean annual temperature and temperature seasonality.Conclusions. Shape and size are representative of convergent temperature-related characters in this genus. Our analysis validates the use of this genus for taxon-free paleoclimatic reconstruction methods relying on such data. The absence of phylogenetic signal in size-and shape-related traits contrasts with earlier studies on distantly related taxa and confirms that historical constraint on leaf morphology is variable among families.
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