Caecilians are predominantly burrowing, elongate, limbless amphibians that have been relatively poorly studied. Although it has been suggested that the sturdy and compact skulls of caecilians are an adaptation to their head-first burrowing habits, no clear relationship between skull shape and burrowing performance appears to exist. However, the external forces encountered during burrowing are transmitted by the skull to the vertebral column, and, as such, may impact vertebral shape. Additionally, the muscles that generate the burrowing forces attach onto the vertebral column and consequently may impact vertebral shape that way as well. Here, we explored the relationships between vertebral shape and maximal in vivo push forces in 13 species of caecilian amphibians. Our results show that the shape of the two most anterior vertebrae, as well as the shape of the vertebrae at 90% of the total body length, is not correlated with peak push forces. Conversely, the shape of the third vertebrae, and the vertebrae at 20% and 60% of the total body length, does show a relationship to push forces measured in vivo. Whether these relationships are indirect (external forces constraining shape variation) or direct (muscle forces constraining shape variation) remains unclear and will require quantitative studies of the axial musculature. Importantly, our data suggest that mid-body vertebrae may potentially be used as proxies to infer burrowing capacity in fossil representatives.
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RBINS Staff Publications 2022
Morphometric characters of fossil leaves such as size and shape are important and widely used sources for reconstructing palaeoenvironments. Various tools, including CLAMP or Leaf Margin Analysis, utilize leaf traits as input parameters for estimating palaeoclimate, mostly based on correlations between traits and climate parameters of extant plants. During the last few years, the scope of information extracted from the morphology of fossil leaves has been further expanded by including leaf economics, which describe correlations between functional leaf traits and ecological strategies. The amount and quality of available data are essential for a successful palaeoecological analysis utilizing leaf traits. Here, the database MORPHYLL is described. This database is devised to offer a web-based resource for fossil leaf trait data. For this purpose, fossil leaves from various collections were digitized and morphometric traits extracted from leaf outlines. Besides metadata such as accession number, repository, fossil site or taxonomic information (for identified specimens), MORPHYLL offers queries for several morphometric parameters and derived ecophysiological traits (e.g., leaf mass per area). Currently, the database contains data from about 6000 fossil leaves from sites in Central Europe, spanning almost the entire Paleogene and part of the early Neogene. The application potential of the database is demonstrated by conducting some exemplary analyses of leaf traits for the Paleocene, Eocene and Oligocene, with the results indicating changes of mean leaf traits through time. For example, the results show leaf mass per area to peak during the Eocene, which is in accordance with general climate development during the Paleogene.
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RBINS Staff Publications 2018
