Imaging of Jurassic fossils from the Talbragar Fish Bed using fluorescence, photoluminescence, and elemental and mineralogical mapping

Abstract

The Talbragar Fish Bed is one of Australia’s most important Jurassic deposits for freshwater fishes, land plants and aquatic and terrestrial insects. The site has yielded many well preserved fossils, which has led to the formal description of numerous new species and higher taxa. The excellent preservation of many fossils has allowed detailed anatomical studies, e.g. of the early teleost fish Cavenderichthys talbragarensis (Woodward, 1895). Here we report on the fluorescent characteristics and mineral composition of a range of Talbragar fossils. Most specimens fluoresce under ultraviolet, blue and green light. Elemental and mineralogical analyses revealed that the Talbragar fossils consist predominantly of quartz (SiO2), a mineral that is likely to account for the observed fluorescence, with trace kaolinite (Al2Si2O5(OH)4) in some of the fish fossils. Rock matrices are predominantly composed of quartz and goethite (FeO(OH)). Closer inspection of a plant leaf (Pentoxylon australicum White, 1981) establishes fluorescence as a useful tool for the visualisation of anatomical details that are difficult to see under normal light conditions.

Biofinder detects biological remains in Green River fish fossils from Eocene epoch at video speed

“…These results corroborate with the recent findings of biomarkers in fossils 26 – 43 . Fluorescence microscopes 44 and examination under UV illumination 45 , 46 have been used in the past to investigate fossils. These methods are limited in their capability because of difficulty in performing in-situ detection during daylight and inability to separate out interferences from mineral phosphorescence.…”

Otoliths in situ in the stem teleostCavenderichthys talbragarensis(Woodward, 1895), otoliths in coprolites, and isolated otoliths from the Upper Jurassic of Talbragar, New South Wales, Australia

“…The instrument was equipped with an Rh anode tube, operated at 50 kV and 200 µA for quantification, and imaging data were collected with a resolution of 25 µm and in 30-µm steps. For elemental compositions, a fundamental parameters routine was modified, with major elements being expressed as oxides (following the mineralogy in Frese et al, 2017) and oxygen being set as the balance element. The following elements-aluminum (Al), silicon (Si), phosphorus (P), potassium (K), calcium (Ca), titanium (Ti), manganese (Mn), and iron (Fe) are reported with a limit of reporting of 0.001 wt%.…”

Improving Vertebrate Skeleton Images: Fluorescence and the Non-Permanent Mounting of Cleared-and-Stained Specimens

“…Their study emphasized the use of fluorescence when examining minute skeletal elements without the need for dissection. Additionally, paleontologists have used various forms of photoluminescence to aid the identification of fossilized elements relative to the surrounding matrix (e.g., Kaye et al, 2015;Frese et al, 2017). Finally, many researchers have identified the presence of biofluorescence (e.g., Sparks et al, 2014;Taboada et al, 2017;Smith et al, 2018) or the ecological role of fluorescence (e.g., Gerlach et al, 2014;Gruber et al, 2016) in living vertebrates.…”