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The Rhynie Chert (Lower Devonian, Scotland) hosts a remarkably well‐preserved early terrestrial ecosystem. Organisms including plants, fungi, arthropods, and bacteria were rapidly silicified due to inundation by silica‐rich hot spring fluids. Exceptional molecular preservation has been noted by many authors, including some of the oldest evidence of lignin in the fossil record. The evolution of lignin was a critical factor in the diversification of land plants, providing structural support and defense against herbivores and microbes. However, the timing of the evolution of lignin decay processes remains unclear. Studies placing this event near the end of the Carboniferous are contradicted by evidence for fungal pathogenesis in Devonian plant fossils, including from the Rhynie Chert. We conducted organic geochemical analyses on a Rhynie Chert sample, including hydropyrolysis (HyPy) of kerogen and high‐resolution mass spectrometric mapping of a thin section, to elucidate the relationship between lignin and the potential fungal marker perylene. HyPy of kerogen showed an increase in relative abundance of perylene supporting its entrapment within the silicate matrix of the chert. Lignin monomers were isolated through an alkaline oxidation process, showing a distribution dominated by H‐type monomers. G‐ and S‐type monomers were also detected, preserved by rapid silicification. Polycyclic aromatic hydrocarbons including perylene, a known marker for lignin‐degrading fungi, were also concentrated in the kerogen and found to be localized within silicified plant fragments. Our results strongly link perylene in the Rhynie Chert to the activity of phytopathogenic fungi, demonstrating the importance of fungal degradation processes as far back as the Early Devonian. [ABSTRACT FROM AUTHOR]

Context. Identification earlier in life of beef cattle with capacity for increased marbling, improved carcase yield and/or reduced subcutaneous fatness can facilitate more rapid genetic improvement and identification of cattle more appropriate forfeedlot or pasture finishing. Earlierin life, ultrasound predictions have potential for significant improvements in compliance with market specifications and overall efficiency of beef production systems. Aims. To assess the relationships just prior to slaughter and earlier in life between measurements of intramuscular fat, subcutaneous fat and eye-muscle (Longissimus thoracis et lumborum) cross-sectional area made using ultrasound, and carcase fatness, muscling and yield measurements following slaughter of Bos taurus steers that differed genetically in potential for subcutaneous fatness and marbling. Methods. Ultrasound measurements of intramuscularfat (IMF), rib fat (RFT), P8 rump fat (P8FAT), eye-muscle area (EMA) and retail beef yield (RBY) of cattle heterogeneous for marbling and fat distribution were made at six stages of growth from weaning to long-feedlotting. Carcase measurements of the same traits were made at five stages of growth from weaning through to long-feedlotting. Key results. IMF ultrasound scans 168 days post-weaning were more strongly correlated (r = 0.79) with marbling in the carcase following long-feedlotting than were IMF ultrasound scans at the end of backgrounding (r = 0.71, 326 days post-weaning), short-feedlotting (r = 0.69, 431 days) and during (r = 0.59, 521 days) and at the end of long-feedlotting (r = 0.53, 585 days). P8FAT was the trait with the highest and most consistent accuracy across all stages of life (r = 0.80) between ultrasound and carcase measurements of P8FAT. Conclusions. The results of the present study showed that ultrasound-scanned measures of carcase IMF, subcutaneous fat and EMA can be used to predict carcase characteristics with good accuracy earlier in life. Implications. The finding that prediction of marbling in the carcase of long-feedlot-fed cattle was stronger by using ultrasound measurement of IMF in younger post-weaned cattle than in older post-weaned cattle warrants further investigation for genetic improvement and management applications, including using newer scanning technologies. [ABSTRACT FROM AUTHOR]