Taphonomic and Diagenetic Pathways to Protein Preservation, Part I: The Case of Tyrannosaurus rex Specimen MOR 1125

Many recent reports have demonstrated remarkable preservation of proteins in fossil bones dating back to the Permian. However, preservation mechanisms that foster the long-term stability of biomolecules and the taphonomic circumstances facilitating them remain largely unexplored. To address this, we examined the taphonomic and geochemical history of Tyrannosaurus rex specimen Museum of the Rockies (MOR) 1125, whose right femur and tibiae were previously shown to retain still-soft tissues and endogenous proteins. By combining taphonomic insights with trace element compositional data, we reconstruct the postmortem history of this famous specimen. Our data show that following prolonged, subaqueous decay in an estuarine channel, MOR 1125 was buried in a coarse sandstone wherein its bones fossilized while interacting with oxic and potentially brackish early-diagenetic groundwaters. Once its bones became stable fossils, they experienced minimal further chemical alteration. Comparisons with other recent studies reveal that oxidizing early-diagenetic microenvironments and diagenetic circumstances which restrict exposure to percolating pore fluids elevate biomolecular preservation potential by promoting molecular condensation reactions and hindering chemical alteration, respectively. Avoiding protracted interactions with late-diagenetic pore fluids is also likely crucial. Similar studies must be conducted on fossil bones preserved under diverse paleoenvironmental and diagenetic contexts to fully elucidate molecular preservation pathways.

Ancient creatures of Hungary: Bringing the animals to life

ABSTRACT The first trace fossils in Hungary, dinosaur footprints, were found in the coal mines of the Mecsek Mountains. The footprints belonged to small theropod dinosaurs. The first fossil bones of vertebrate animals from present-day Hungary were found in 2000 in the mountainous region of Bakony. Numerous taxa have been collected from the locality of Iharkút. These fossils represent a diverse fauna (including fishes, amphibians, turtles, lizards, crocodilians, dinosaurs, birds, and pterosaurs) that lived between 85.8 and 83.5 m.y. ago in the Santonian Age during the Late Cretaceous period. Paleoart can depict these fossil remains in an engaging way to help inform the public about the ancient creatures of Hungary. This chapter provides an overview of how the Mesozoic vertebrates from Hungary have been reconstructed for scientists and the public.

Late Pleistocene fossil hominids tracks on the beaches of Claromecó, Argentina

Fossil ichnites of hominids found in Argentina are identified and described. The age of the sediments was determined using radiocarbon dating, by Uranium, OSL and paleomagnetic signatures of the sediments, along with an analysis of the associated megammalian tracks and their fossil bones. We conclude that the fossil ichnites dated about 30 ka BP.

“He Fell in and That's How He Became a Fossil!”: Engagement With a Storytelling Exhibit Predicts Families' Explanatory Science Talk During a Museum Visit

Parent-child conversations in everyday interactions may set the stage for children's interest and understanding about science. Studies of family conversations in museums have found links to children's engagement and learning. Stories and narratives about science may spark children's interest in science topics. This study asks whether a museum exhibit that provides opportunities for families to create narratives might encourage families' explanatory science talk throughout the rest of the exhibit. The project focused on the potential impact of a hands-on story-telling exhibit, the “spin browser” embedded within a larger exhibition focused on fossilized mammoth bones—Mammoth Discovery! at Children's Discovery Museum of San Jose. Participants were 83 families with children between 3 and 11 years (mean age 7 years). We coded families' narrative talk (telling stories about the living mammoth or the fossil discovery) and connecting talk (linking the story to other nearby exhibits) while families visited the spin browser, and we also coded families' explanatory science talk at the exhibits that contained authentic fossil bones and replica bones. The parents in families who visited the spin browser (n = 37) were more likely to engage in science talk at the fossil exhibits than those in families who did not visit the spin browser (n = 46). Further, a regression analysis showed that family science talk at the fossil exhibits was predicted by parents' connections talk and children's narrative talk at the spin browser. These findings suggest that families' narratives and stories may provide an entry point for science-related talk, and encourage future study about specific links between storytelling and science understanding.

Digital 3D models of theropods for approaching body-mass distribution and volume

The aim of this work is to obtain diverse morphometric data from digitized 3D models of scientifically accurate palaeoreconstructions of theropods from eight representative families. The analysed polyvinyl chloride (PVC) models belong to the genera Coelophysis, Dilophosaurus, Ceratosaurus, Allosaurus, Baryonyx, Carnotaurus, Giganotosaurus, and Tyrannosaurus. The scanned 3D models were scaled considering different body-size estimations of the literature. The 3D analysis of these genera provides information on the skull length and body length that allows for recognition of major evolutionary trends. The skull length/body length in the studied genera increases according with the size of the body from the smallest Coelophysis with a ratio of 0.093 to ratios of 0.119–0.120 for Tyrannosaurus and Giganotosaurus, the largest study theropods. The study of photogrammetric 3D models also provides morphometric information that cannot be obtained from the study of bones alone, but knowing that all reconstructions begin from the fossil bones, such as the surface/volume ratio (S/V). For the studied theropod genera surface/volume ratio ranges from 35.21 for Coelophysis to 5.55 for Tyrannosaurus. This parameter, closely related to the heat dissipation, help in the characterization of the metabolism of extinct taxa. Accordingly, slender primitive forms of the Early Jurassic (i.e. Coelophysis and Dilophosaurus) had relatively smaller skulls and higher mass-specific metabolic rates than the robust large theropods of the Cretaceous (i.e. Giganotosaurus and Tyrannosaurus). This work presents a technique that, when applied to proper dinosaur models, provides extent and accurate data that may help in diverse study areas within the dinosaur palaeontology and palaeobiology.

Tracing the spatial imprint of Oldowan technological behaviors: A view from DS (Bed I, Olduvai Gorge, Tanzania)

DS (David’s site) is one of the new archaeological sites documented in the same paleolandscape in which FLK 22 was deposited at about 1.85 Ma in Olduvai Gorge. Fieldwork in DS has unearthed the largest vertically-discrete archaeological horizon in the African Pleistocene, where a multi-cluster anthropogenic accumulation of fossil bones and stone tools has been identified. In this work we present the results of the techno-economic study of the lithic assemblage recovered from DS. We also explore the spatial magnitude of the technological behaviors documented at this spot using powerful spatial statistical tools to unravel correlations between the spatial distributional patterns of lithic categories. At DS, lavas and quartzite were involved in different technological processes. Volcanic materials, probably transported to this spot from a close source, were introduced in large numbers, including unmodified materials, and used in percussion activities and in a wide variety of reduction strategies. A number of volcanic products were subject to outward fluxes to other parts of the paleolandscape. In contrast, quartzite rocks were introduced in smaller numbers and might have been subject to a significantly more intense exploitation. The intra-site spatial analysis has shown that specialized areas cannot be identified, unmodified materials are not randomly distributed, percussion and knapping categories do not spatially overlap, while bipolar specimens show some sort of spatial correlation with percussion activities.

Polyester or epoxy: assessing embedding product efficacy in paleohistological methods

Histological examination of bone microstructure provides insight into extant and extinct vertebrate physiology. Fossil specimens sampled for histological examination are typically first embedded in an inexpensive polyester resin and then cut into thin sections, mounted on slides, and polished for viewing. Modern undecalcified bone is chemically processed prior to embedding in plastic resin, sectioning, mounting, and polishing. Conversely, small fossil material and modern undecalcified bone are typically embedded in higher priced epoxy resin because these specimen types require final sections near or below 100 µm thick. Anecdotal evidence suggests thin sections made of polyester resin embedded material polished thinner than 100 µm increases likelihood of sample peeling, material loss, and is unsuitable for modern tissue and small fossil material. To test this assertion, a sample of modern bones and fossil bones, teeth, and scales were embedded in either polyester resin or epoxy resin. Embedded specimens were sectioned and mounted following standard published protocol. Thin sections were ground on a lapidary wheel using decreasing grit sizes until tissue microstructure was completely discernible when viewed under a polarizing light microscope. Additionally, eight prepared thin sections (four from polyester resin embedded specimens and four from epoxy resin embedded specimens) were continuously ground on a lapidary wheel using 600 grit carbide paper until peeling occurred or material integrity was lost. Slide thickness when peeling occurred was measured for comparing slide thickness when specimen integrity was lost between the two resin types. Final slide thickness ranged from 38 µm to 247 µm when tissue was identifiable using a polarizing microscope. Finished slide thickness varied between resin types despite similar tissue visibility. However, finished slide thickness appears more dependent on hard tissue composition than resin type. Additionally, we did not find a difference of slide thickness when material was lost between resin types. The results of this preliminary study suggest that polyester resins can be used for embedding undecalcified modern hard tissues and fossilized hard tissues without loss of tissue visibility or material integrity, at least in the short term.

Diagenetic processes in Quaternary fossil bones from tropical limestone caves

Quaternary fossils from limestone caves bear various diagenetic features due to the complex nature of sedimentary processes. However, few studies have addressed the problem of diagenetic changes in fossils from tropical-wet environments. We study Quaternary fossil bones from different sites of a tropical limestone cave in northeastern Brazil. These fossils show diverse diagenetic features. The approach encompassed the use of scanning electron microscopy, Raman spectroscopy, and X-ray diffraction to understand the modification of the fossil bone structure, chemical composition, and mineral assemblage during the diagenesis processes. We describe a model for fossil diagenesis in tropical limestone caves that involves early and advanced diagenetic stages, which produce two routes with different endmembers. The diagenesis in the cave alters the crystallinity and ordering of hydroxyapatite. The recrystallization of hydroxyapatite appears to be strongly influenced by dripping water that is rich in calcium carbonate, which leads to crystal formation with higher crystallinity. In the absence of calcium carbonate, hydroxyapatite diagenesis involves crystal growth but not necessarily dissolution of the original material, which enables remarkable preservation of the biological structure.

A new extinct species of Polynesian sandpiper (Charadriiformes: Scolopacidae: Prosobonia) from Henderson Island, Pitcairn Group, and the phylogenetic relationships of Prosobonia

We describe a new species of Polynesian sandpiper from Henderson Island, Prosobonia sauli sp. nov., based on multiple Holocene fossil bones collected during the Sir Peter Scott Commemorative Expedition to the Pitcairn Islands (1991–92). Prosobonia sauli is the only species of Prosobonia to be described from bone accumulations and extends the record of known extinct Polynesian sandpipers to four. It is readily differentiated from the extant Tuamotu Sandpiper P. parvirostris in several features of the legs and bill, implying ecological adaptations to different environments. The geographically nearest Prosobonia populations to Henderson Island were found on Mangareva, where it is now extinct. A previous record of a species of Prosobonia from Tubuai, Austral Islands, is here shown to belong to the Sanderling Calidris alba. Our analyses of newly sequenced genetic data, which include the mitochondrial genomes of P. parvirostris and the extinct Tahiti Sandpiper P. leucoptera, confidently resolve the position of Prosobonia as sister-taxon to turnstones and calidrine sandpipers. We present a hypothesis for the timing of divergence between species of Prosobonia and other scolopacid lineages. Our results further provide a framework to interpret the evolution of sedentary lineages within the normally highly migratory Scolopacidae.