Evidence of a Hopping, Bipedal Mammaliform From Cretaceous Korea

Korean trackway of a hopping, mammaliform trackmaker is global first from the Cretaceous

Authors:

Kim et al

Abstract:

A trackway of a small hopping mammaliform trackmaker from the Jinju Formation (Lower Cretaceous) of the Jinju City area, Korea, is the first of this type reported from the Mesozoic of Asia, and globally. The animal left a narrow trackway (∼20 mm wide) with small tetradactyl footprints averaging less than 10 mm in diameter. Only two footprints registered with each hop (mean length 41 mm) thus indicating a bipedal gait. All trackway evidence suggests a small “mouse-like” trackmaker. Previous reports of trackways made by hopping tetrapods from the Mesozoic are rare and presently restricted to ichnogenus Ameghinichnus isp. indet., from the Jurassic of Argentina. Ichnogenus Musaltipes from the Cenozoic of North America, is the only other ichnogenus representing a hopping mammal. The Korean specimen here named Koreasaltipes jinjuensis, is different from these aforementioned ichnogenera in digit count, digit proportion and trackway configuration, as well as lack of tail trace. Koreasaltipes jinjuensis is from a lake shore paleoenvironment associated with nematode tracks (Cochlichnus isp.), other small tetrapod tracks attributed to avian theropods (birds), pterosaurs and crocodylomorphs, as well as larger saurischian dinosaurs.

Coprolites Give Evidence of Early Triassic Polar Predators

An Early Triassic polar predator ecosystem revealed by vertebrate coprolites from the Bulgo Sandstone (Sydney Basin) of southeastern Australia

Authors:

Niedźwiedzki et al

Abstract:

Vertebrate trace fossils often provide a measure of cryptic biodiversity, and are especially pertinent when skeletal remnants are exceptionally rare. The Lower Triassic (lower Olenekian) Bulgo Sandstone at Long Reef in the Sydney Basin of southeastern Australia constitutes just such a deposit, having yielded isolated bones of giant capitosaurian temnospondyls and proterosuchid archosauriforms, together with abundant coprolites that are geochemically rich in elemental phosphate and carbon denoting vertebrate predators. Microstructural analysis of these preserved droppings reveals occasional bone fragments, fish scales, insect cuticles, plant material and bacterial traces (pseudomorph voids), as well as silicate mineral particles. REE concentrations indicate that burial and early diagenesis occurred explicitly within fluvial sediments. Furthermore, external morphological characterization permits attribution of spiral coprolites to chondrichthyan or osteichthyan fishes, polygonal, ovoid–spherical and typically flattened feces to temnospondyls, and conspicuously large cylindrical droppings to archosauriforms or other amniote apex predators. Collectively, the Bulgo Sandstone coprolite assemblage thus offers new insights into ecosystem structure and palaeoenvironment in what was an earliest Triassic near polar setting. Such data compliments the documented skeletal record, but indicates a greater range of aquatic and possibly terrestrial carnivores — the latter being enigmatically sparse in the Australian Triassic and yet detected here via the hitherto underexplored trace fossil evidence of their ecological presence.

Are Ediacaran Ambient Inclusion Trails Trace Fossils?

New observations of Ambient Inclusion Trails (AITs) and pyrite framboids in the Ediacaran Doushantuo Formation, South China

Authors:

She et al

Abstract:

Ambient Inclusion Trails (AITs) are intriguing microtubular structures that commonly occur in association with pyrite in Precambrian organic-rich cherts and phosphorites. They are thought to be created by the migration of pyrite or other crystal grains through a lithified substrate driven by pressure solution from the in situ thermal decomposition of organic matter. New phosphorite samples of the Ediacaran Doushantuo Formation (South China) contain abundant AITs exhibiting diverse morphotypes, which may be distinguished from filamentous microfossils and endolithic microborings with a suite of morphological criteria based on optical microscopy and scanning electron microscopy (SEM). Black shales of the Baizhu section contains abundant pyrite framboids whose size distributions reveal significant temporal variations of redox conditions in shallow marine waters that probably promoted the formation of the Doushantuo phosphorites.

AITs in the phosphorites are categorized into three types and further into five subtypes (I-a, I-b, II-a, II-b, and III) based on their morphologies and observed or interpreted associations with various kinds of terminal pyrite crystals. Among these, subtype II-a, single striated microtubes 2–10 μm wide, are interpreted to have resulted from migration of intact pyrite framboids. Those of subtype II-b, dense clusters of outward radiating microtubes with consistent widths and inward-facing cuspate ridges, likely have formed by explosive disintegration and propulsion of pyrite framboids due to highly concentrated carbon dioxide gas during the oxidation of organic matter. During early diagenesis, formation of euhedral and framboidal pyrites involve a suite of biogeochemical and physical processes including non-biological oxidation of organic matter and reduction of sulfate in the presence of ferrous iron. Following the burial of pyrites, further oxidative degradation of organic matter produced abundant CO2 gas, which drives the pyrites to move through the solid, but not yet fully lithified phosphatic gel composing granules. This model explains the formation of previously reported but unexplained star-burst type AITs and it may be tested by experimental studies.

Our new observations provide evidence for the widespread occurrence of AITs in the Doushantuo phosphorites and urge careful petrographic examinations and differentiation between AITs and morphologically similar biogenic microstructures.

Evidence of Eukaryote Fossils From the NeoArchean?

Tubular microfossils from ∼2.8 – 2.7 Ga-old lacustrine deposits of South Africa: a sign for early origin of eukaryotes?

Authors:

Kaźmierczak et al

Abstract:

Unequivocal evidence for Archean eukaryotic life has been long sought for and is a matter of lively debate. In the absence of unambiguous fossils this debate has focused on biogeochemical signatures and molecular phylogenies. Most researchers agree that fossil forms comparable with modern eukaryotic cells can be credibly identified only in Proterozoic (∼1.8-1.6 Ga) and younger rocks. Herein, we report for the first time, Neoarchean mineralized tubular microfossils from ∼2.8-2.7 Ga lacustrine deposits of South Africa. The exceptional preservation of these microfossils allows recognition of important morphological details in petrographic thin section and in HF-macerates that links them to modern siphonous (coenocytic) green or yellow-green microalgae (Chlorophyta and Xanthophyta). The microfossil identification is supported by Raman spectroscopic analyses, EPMA, SEM/BSE and SEM/EDS microprobe analytical results, NanoSIMS elemental mapping and micro-tomographic sectioning of the thalli. All results point to indigenous, bona fide eukaryotic microfossils of algal affinity. These Neoarchean microalgae-like remains and their assumingly combined in vivo and early post-mortem precipitated mineral envelopes greatly improve our knowledge of early life and its habitats and may have far-reaching consequences for the studies of the evolution of life.

A Giant Abelisaurus Theropod Foot Print Found in Bolivia

A footprint measuring over a metre wide has been discovered in the southern American country of Bolivia. It's thought to have been made by an Abelisaurus, a meat-eating dinosaur that walked the Earth millions of years ago. Palaeontologist Sebastian Apesteguia went to the site of the discovery.

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Microbially Induced Sedimentary Structures From Paleoproterozoic Canada

Microbially induced sedimentary structures in the Paleoproterozoic, upper Huronian Supergroup, Canada

Authors:

Hill et al

Abstract:

The Paleoproterozoic Gordon Lake and Bar River formations, Huronian Supergroup, contain a variety of sedimentary structures in the Flack Lake area of Ontario, Canada, that have been considered of debatable origin. We identify these structures as microbially induced sedimentary structures (MISS). The preserved MISS are related to microbial mat destruction and decay, and include sand cracks, mat chips, remnant gas domes, pyrite patches, and iron laminae. A biological origin for the fossil structures is supported by their similarities to modern and ancient documented examples of MISS, the sand-dominated nature of the substrate in which they are preserved, and key microtextures identified in thin section. Microtextures include curled, frayed and layered mat chips, carbonaceous laminae, oriented grains, and concentrated heavy minerals. On outcrop scale, the presence of desiccation cracks, flaser and lenticular bedding, and ripples in association with the types of MISS identified in the Gordon Lake Formation support the interpretation of a tidal flat depositional environment. The Gordon Lake Formation contains a greater number and diversity of MISS than the overlying Bar River Formation, as a result of lower energy deposition in the former. The quartz arenite of the Bar River Formation contains fine-grained to pebbly granulestone characterized mainly by tangential and planar cross beds, which is consistent with a tidal channel or sand shoal setting. Although fossil evidence of life is rare in the rocks of the Huronian Supergroup, identification of MISS in the Flack Lake area provides a significant and convincing indication of microbial colonization at the time of deposition.

Evidence of a Microbial Dominated Ocean During the Late MesoProterozoic

Carbonate rocks and related facies with vestiges of biomarkers: Clues to redox conditions in the Mesoproterozoic ocean

Authors:

Patranabis-Deb et al

Abstract:

The Raipur Group of the Chattisgarh Basin preserves two major Late Mesoproterozoic carbonate platforms. The lower platform is about 490-m thick, separated from the upper platform (~ 670 m thick) by a 500-m thick calcareous shale. Carbonate strata cover almost 40% of the Chattisgarh Basin outcrop and represent two major platform types: a) a non-stromatolitic ramp (the Charmuria/Sarangarh Limestone) and b) a platform developed chiefly in the intertidal to shallow subtidal environment with prolific growth of stromatolites (the Chandi/Saradih Limestone). The first platform consists primarily of the black Timarlaga limestone that is locally replaced by early diagenetic dolomite. This carbonate platform experienced strong storm waves and was subsequently drowned by a major transgression, during which extensive black limestone–marl rhythmite was deposited, followed by deposition of the Gunderdehi Shale. The carbonate factory was later re-established with development of an extensive stromatolite-dominated Charmuria/Sarangarh platform that ranged from restricted embayment to open-marine conditions. Sea-level change played a major role in controlling the broad facies pattern and platform evolution. The δ13C signatures of the Chattisgarh limestones, falling within a relatively narrow range (0 to + 4‰) are typical for Upper Mesoproterozoic carbonate rocks. δ18O values, however, have a greater range (− 5.7 to − 13.3‰) indicating significant diagenetic alteration of some samples. Likely dysoxic or anoxic conditions prevailed during deposition of the black Timarlaga limestone and well-oxygenated conditions during deposition of the Gunderdehi Shale and Saradih/Chandi stromatolite. The lack of 17β,21α (moretanes) and high Tmax values suggest mature organic matter in the non-stromatolitic ramp. A paucity of diagnostic eukaryotic steroids indicates that algae were rare in the Chattisgarh Basin. A high content of hopanes supports a generally bacterially-dominated Proterozoic ocean in which various stromatolites flourished.

Small scale scrapes suggest avian display behavior by diminutive Cretaceous theropods

Small scale scrapes suggest avian display behavior by diminutive Cretaceous theropods

Authors:

Kim et al

Abstract:

A set of about 25 diminutive sub-parallel scrapes in the Cretaceous Haman Formation of South Korea fit the morphology of the small theropod track Minisauripus which is also known from this formation. The scrapes are interpreted as evidence of display behavior, and suggest that the trace maker was an adult engaged in avian-like courtship behavior. Although avian theropods are also known from this formation, the scrapes are inconsistent with their foot morphology. Although large theropod scrapes have been interpreted as evidence of display behavior they are only known from North America. Thus, the scrapes described here are the first reported from Asia, and the first interpreted as evidence of display behavior in such a diminutive species.

Evidence of Predation (!!) From the Tonian NeoProterozoic

Tiny vampires in ancient seas: evidence for predation via perforation in fossils from the 780–740 million-year-old Chuar Group, Grand Canyon, USA

Author:

Porter

Abstract:

One explanation for the Early Neoproterozoic expansion of eukaryotes is the appearance of eukaryovorous predators—i.e. protists that preyed on other protists. Evidence for eukaryovory at this time, however, is indirect, based on inferences from character state reconstructions and molecular clocks, and on the presence of possible defensive structures in some protistan fossils. Here I describe 0.1–3.4 µm circular holes in seven species of organic-walled microfossils from the 780–740 million-year-old Chuar Group, Grand Canyon, Arizona, USA, that are similar to those formed today by predatory protists that perforate the walls of their prey to consume the contents inside. Although best known in the vampyrellid amoebae, this ‘vampire-like’ behaviour is widespread among eukaryotes, making it difficult to infer confidently the identity of the predator. Nonetheless, the identity of the prey is clear: some—and perhaps all—of the fossils are eukaryotes. These holes thus provide the oldest direct evidence for predation on eukaryotes. Larger circular and half-moon-shaped holes in vase-shaped microfossils from the upper part of the unit may also be the work of ‘tiny vampires’, suggesting a diversity of eukaryovorous predators lived in the ancient Chuar sea.

Small Theropod Dinosaurs Scraped out Display Areas Like Birds

Small scale scrapes suggest avian display behavior by diminutive Cretaceous theropods

Authors:

Kim et al

Abstract:

A set of about 25 diminutive sub-parallel scrapes in the Cretaceous Haman Formation of South Korea fit the morphology of the small theropod track Minisauripus which is also known from this formation. The scrapes are interpreted as evidence of display behavior, and suggest that the trace maker was an adult engaged in avian-like courtship behavior. Although avian theropods are also known from this formation, the scrapes are inconsistent with their foot morphology. Although large theropod scrapes have been interpreted as evidence of display behavior they are only known from North America. Thus, the scrapes described here are the first reported from Asia, and the first interpreted as evidence of display behavior in such a diminutive species.

Candidate microbial ichnofossils in continental basaltic tuffs of central Oregon

Candidate microbial ichnofossils in continental basaltic tuffs of central Oregon, USA: Expanding the record of endolithic microborings

Authors:

Nikitczuk et al

Abstract:

The presence of potential microbial trace fossils (endolithic microborings) has been well documented in oceanic basaltic pillow lavas, hyaloclastites, tuffs, and transitional subglacial marine lavas in the past 30 yr. Despite their evident abundance in oceanic to subglacial environments, they have not been observed in continental basalts that were not erupted in marine or subglacial settings. To expand the record of putative endolithic microborings in volcanic rocks to nonmarine, continental lacustrine environments, we examined hydrovolcanic pyroclastic deposits in the Fort Rock volcanic field, central Oregon. This study presents the textures, mineralogy, and geochemistry of basaltic tuffs containing possible endolithic microborings comparable in morphology, size, and distribution to those described in earlier oceanic and subglacial basalt studies. We observed a variety of tubular and granular textures that show evidence of biogenic morphologies and behavior, and a primary geological context that expresses their age and syngenicity. Petrographic relationships with secondary phases (chabazite, nontronite, calcite) indicate that the construction of microtunnels occurred in saline, alkaline fluids at temperatures of 25−80 °C. In addition, positive correlations were observed between the extent of aqueous (abiotic) alteration and both the abundance of microtunnels and morphological type. These correlations suggest that microtunnels were more readily formed where there was greater abiotic alteration-fluid flux and that the resulting change in chemical composition of those fluids may have had a direct influence on the formation process or possibly the type of constructing microbe. This work adds to understanding of factors controlling microtunnel formation and is the first account of putative endolithic microborings in a continental lacustrine setting. This new information may also have implications in the search for habitable extraterrestrial environments, such as on Mars.

A Dinosaur Footprint Found From Carnian Triassic Spain?

Spain says a footprint of a dinosaur that roamed the area 230 million years ago has been found in northeastern Catalonia, and says it's the best preserved dinosaur print seen so far in the Iberian Peninsula.

The print of a reptile-like creature called an Isochirotherium — an ancestor of dinosaurs and crocodiles — was discovered in early April by a person out walking in Olesa de Montserrat, 40 kilometers (25 miles) north of Barcelona.

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Evidence of Microbial Activity From PaleoArchean Australia

Carbonaceous microstructures from sedimentary laminated chert within the 3.46 Ga Apex Basalt, Chinaman Creek locality, Pilbara, Western Australia

Authors:

Hickman-Lewis et al

Abstract:

Hydrothermal black chert veins intruding the 3.46 Ga Apex Basalt contain some of Earth’s oldest microfossil-like objects, whose biogenicity has been questioned. Whilst these black chert veins have been studied in great detail, relatively little is known about the stratiform, seafloor, sedimentary cherts that are conformably interbedded with volcanic rocks of the Apex Basalt.

Herein, we document and assess the biogenicity of carbonaceous microstructures present in the lowermost of the stratiform chert units (informally known as the ‘Apex chert’), at the Chinaman Creek locality in the Marble Bar greenstone belt, Pilbara Craton, Western Australia. Carbonaceous material mostly occurs within clotted grey-black cherts and microgranular ‘grainstone-like’ cherts within the stratiform unit, the latter being the major focus of this study. In the clotted cherts, carbon occurs as lobate, fluffy grains, rare compressed flakes, and as a grain boundary phase around spherulitic silica. There is no morphological evidence to support the biogenicity of these microstructures. In contrast, the microgranular chert contains fluffy and flaky carbonaceous grains, plus laminated grains comprising multiple non-isopachous wrinkled carbonaceous laminae, with noted thickening towards some ridge crests, as determined by confocal laser scanning microscopy. Roll-up structures provide evidence of an initial plasticity, interpreted to have formed via the tearing-up and current-induced plastic deformation of microbial mat fragments. Geochemical mapping, using laser Raman micro-spectroscopy and NanoSIMS, respectively demonstrates the antiquity of the carbon, and reveals a close correlation between carbon, nitrogen and sometimes sulphur, concentrated within dark brown to black laminae. Adjacent to microgranular zones are zones of more persistent carbonaceous, undulose, filament-like laminae that entrain relict sediment grains. These microstructures are directly comparable to a sub-type of microbially induced sedimentary structure (MISS), widely reported from younger siliciclastic sediments colonised by microbial biofilms.

The morphology and chemical composition of both the non-isopachous laminated grains and the filament-like laminae are consistent with a biological interpretation, suggesting microscopic MISS were present in the microgranular stratiform ‘Apex chert’. However, the fact that neither macroscopic MISS nor bona fide microfossils have yet been reported from this unit, coupled with the proximity of these structures to active hydrothermal vents, potentially discharging hot carbon-rich fluids, urges caution in such an interpretation. The Chinaman Creek ‘Apex chert’ investigated here is one of at least five sedimentary, laminated cherts within the Apex Basalt. These horizons are promising targets in the search for biological activity within a dominantly volcanic Archaean environment.

Evidence of Successions of Different Microbial Biota From MesoArchean South Africa

Sedimentology and facies analysis of Mesoarchaean stromatolitic carbonate rocks of the Pongola Supergroup, South Africa

Authors:

Shishi et al

Abstract:

The c. 3.0 Ga old Chobeni Formation (Nsuze Group, Pongola Supergroup) contains several carbonate successions interpreted to have been deposited in a tide-dominated, shallow-marine environment. Facies consist of mixed siliciclastic and carbonate rocks and include subtidal cross-bedded sandstone and oncolitic dolostone, intertidal wave-rippled oodolarenite, and supratidal wrinkly-laminated dolarenite–dololutite. Sedimentary facies are partially arranged in a shallowing-upward pattern reflecting cyclic variations of Mesoarchaean sea level. Microbialites occur in a variety of sedimentary sub-environments and include laminated as well as structureless, lenticular-domal types. Differences in microbialite morphology, macrofabric, and size suggest potentially distinct assemblages of microorganisms responding to different physicochemical and environmental conditions. Microbialite textures are consistent with in situ carbonate precipitation and to a lesser extent by trapping and binding of sediment. Despite their great age, the Pongola carbonates are compositionally and texturally very similar to much younger carbonate successions preserved in the geological record.

Remains of Blood Vessels Found in Polish Triassic Reptile Bones?

Spectroscopic Studies on Organic Matter from Triassic Reptile Bones, Upper Silesia, Poland

Authors:

Surmik et al

Abstract:

Fossil biomolecules from an endogenous source were previously identified in Cretaceous to Pleistocene fossilized bones, the evidence coming from molecular analyses. These findings, however, were called into question and an alternative hypothesis of the invasion of the bone by bacterial biofilm was proposed. Herewith we report a new finding of morphologically preserved blood-vessel-like structures enclosing organic molecules preserved in iron-oxide-mineralized vessel walls from the cortical region of nothosaurid and tanystropheid (aquatic and terrestrial diapsid reptiles) bones. These findings are from the Early/Middle Triassic boundary (Upper Roetian/Lowermost Muschelkalk) strata of Upper Silesia, Poland. Multiple spectroscopic analyses (FTIR, ToF-SIMS, and XPS) of the extracted "blood vessels" showed the presence of organic compounds, including fragments of various amino acids such as hydroxyproline and hydroxylysine as well as amides, that may suggest the presence of collagen protein residues. Because these amino acids are absent from most proteins other than collagen, we infer that the proteinaceous molecules may originate from endogenous collagen. The preservation of molecular signals of proteins within the "blood vessels" was most likely made possible through the process of early diagenetic iron oxide mineralization. This discovery provides the oldest evidence of in situ preservation of complex organic molecules in vertebrate remains in a marine environment.

This is how a Cambrian Trilobite Hunted

The Cambrian Period, which occurred between 541 million and 485 million years ago, is an important point in evolutionary history where most of the major groups of animals first appear in the fossil record. Often called the "Cambrian explosion," fossils from this time provide glimpses into evolutionary history as the world's ecosystems were rapidly diversifying. Most fossils preserve the physical remains of organisms and their structure; however, geologists and paleobiologists at the University of Missouri recently collaborated to study fossils that reveal the behaviors of predators preserved as traces in ancient sediments. Thus, fossils from southeast Missouri are helping scientists unlock clues about the behaviors of these predators and their interactions with their prey. Evidence shows that these ancient organisms were behaviorally sophisticated, tailoring their attacks for effectiveness.

Trilobites are a fossil group of extinct marine invertebrate animals with external skeletons (see photo). As predators and scavengers, they flourished in the Cambrian period and were very prominent in the oceans that once were located in Missouri.

"The Saint Francois Mountains in southeastern Missouri have been the focus of geological research for decades and were once islands in the Cambrian ocean," said Kevin Shelton, professor of geological sciences in the MU College of Arts and Science. "I've worked as a geologist studying ore deposits in the area for more than 30 years. In that time, I've run across thousands of fossilized trilobite burrows. It is rare that we get to study the activities of 500 million-year-old organisms, yet the fossils in this locality are helping us determine how these organisms behaved."

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Paleo Awesomeness: Physical Trace Fossil Evidence of Nonavian Theropod Display Arenas for Breeding From Cretaceous Colorado

Theropod courtship: large scale physical evidence of display arenas and avian-like scrape ceremony behaviour by Cretaceous dinosaurs

Authors:

Lockley et al

Abstract:

Relationships between non-avian theropod dinosaurs and extant and fossil birds are a major focus of current paleobiological research. Despite extensive phylogenetic and morphological support, behavioural evidence is mostly ambiguous and does not usually fossilize. Thus, inferences that dinosaurs, especially theropods displayed behaviour analogous to modern birds are intriguing but speculative. Here we present extensive and geographically widespread physical evidence of substrate scraping behavior by large theropods considered as compelling evidence of “display arenas” or leks, and consistent with “nest scrape display” behaviour among many extant ground-nesting birds. Large scrapes, up to 2 m in diameter, occur abundantly at several Cretaceous sites in Colorado. They constitute a previously unknown category of large dinosaurian trace fossil, inferred to fill gaps in our understanding of early phases in the breeding cycle of theropods. The trace makers were probably lekking species that were seasonally active at large display arena sites. Such scrapes indicate stereotypical avian behaviour hitherto unknown among Cretaceous theropods, and most likely associated with terrirorial activity in the breeding season. The scrapes most probably occur near nesting colonies, as yet unknown or no longer preserved in the immediate study areas. Thus, they provide clues to paleoenvironments where such nesting sites occurred.

pop sci writeup.

Very Diverse Dinosaur Trackway has Ornithopod and Pterosaur Traces Amongst Lots of Theropod and Sauropods Tracks

A diverse saurischian (theropod–sauropod) dominated footprint assemblage from the Lower Cretaceous Jiaguan Formation in the Sichuan Basin, southwestern China: A new ornithischian ichnotaxon, pterosaur tracks and an unusual sauropod walking pattern

Authors:

Xing et al

Abstract:

A sample of fallen blocks of fluvial sandstone from the Lower Cretaceous Jiaguan Formation of Sichuan Province yielded an assemblage of dinosaur and pterosaur tracks preserved as natural impressions and casts. Collectively the assemblage reveals 132 tracks representing at least 30 trackways of tridactyl and didactyl theropods, sauropods, ornithopods and pterosaurs. Ichnotaxonomically, the trackways of small tridactyl theropods (pes lengths 7–18 cm) are indeterminable, whereas the trackway of a small didactyl dromaeosaur (pes length up to 7.5 cm) is tentatively assigned to cf. Velociraptorichnus. The sauropod trackways are assigned to cf. Brontopodus based on the medium to nearly wide-gauge pattern. Other characteristics are the U-shaped manus and strong heteropody. One sauropod trackway shows a peculiar pattern with a lack of left manus imprints, and an unusual position and rotation of right manus imprints. Different scenarios and explanations for this phenomenon are discussed. Ornithopod trackways are the most abundant in the sample and characterized by pes imprints of a small biped that are assigned here to the new ichnospecies Caririchnium liucixini. It is characterized by an unusual broad shape and weak mesaxony. Bivariate analysis of different Caririchnium ichnospecies reveals increasing mesaxony toward the larger forms, a trend that is the reverse of typical theropod ichnotaxa, where large imprints have weak mesaxony. Three isolated, small pterosaur tracks (two manus, one pes) are visible on a single surface. They show strong similarities to the widespread ichnogenus Pteraichnus. This is the ninth report of tetrapod tracks from the Jiaguan Formation in recent years and represents one of the most diverse assemblages recorded to date. It is also rare evidence of typical didactyl dromaeosaur tracks and the co-occurrence of sauropod and ornithopod tracks in a fluvial depositional environment representing arid climate conditions.
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Dinosaur Tracks From Middle Jurassic Isle of Skye

A newly discovered collection of rare dinosaur tracks is helping scientists shed light on some of the biggest animals ever to live on land.

Hundreds of footprints and handprints made by plant-eating sauropods around 170 million years ago have been found on the Isle of Skye in Scotland.

The discovery - which is the biggest dinosaur site yet found in Scotland - helps fill an important gap in the evolution the huge, long-necked animals, which were the biggest of the dinosaurs.

Scientists at the University of Edinburgh identified the tracks in layers of rock, which would have been at the bottom of a shallow, salt water lagoon when the prints were made.

By analysing the structure of the footprints, the team found that the dinosaurs were early, distant relatives of more well-known species, such as Brontosaurus and Diplodocus. The Skye dinosaurs likely grew to at least 15 metres in length and weighed more than 10 tonnes.

The footprints - the largest of which is 70 cm in diameter - are the first sauropod tracks to be found in Scotland. Until now, the only evidence that sauropods lived in Scotland came from a small number of bone and teeth fragments.

Fossils from the Middle Jurassic Period are extremely rare, and the Isle of Skye is one of the few places in the world where they can be found.

The discovery is helping scientists to reimagine the habitats and lifestyles of the world's biggest dinosaurs. Together with similar tracks found recently in other parts of the world, the Skye trackways reveal that sauropods spent lots of time in coastal areas and shallow water. It was previously thought that large dinosaurs were purely land-dwellers.

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Pre Mammalian Permian Therapsids Were Hairy: Evidence From Upper Permian Coprolites

Microbiota and food residues including possible evidence of pre-mammalian hair in Upper Permian coprolites from Russia

Authors:

Bajdek et al

Abstract:

Coprolites (fossil faeces) provide direct evidence on the diet of its producer and unique insights on ancient food webs and ecosystems. We describe the contents of seven coprolites, collected from the Late Permian Vyazniki site of the European part of Russia. Two coprolite morphotypes (A, B) contain remains of putative bacteria, cyanobacteria, fungi, protists, invertebrate eggs, arthropod elements, undigested bone and tooth fragments, fish scales and elongated hair-like structures with hollow interiors. Content, size and shape of the coprolites together with the associated body fossil record suggest that the most probable scat-producers were carnivorous tetrapods; the bone-rich morphotype A reveals short food retention time and a fast metabolism and is therefore assigned to therapsid carnivores whereas morphotype B with rarer and degraded bones are assigned to archosauromorphs or other non-therapsid carnivores. The general coprolite matrix contains abundant micron-sized spheres and thin-walled vesicles which are interpreted as oxide and phosphatic pseudomorphs after microbial cells. From analyses of the undigested bones, we infer that they represent remains of actinopterygian fish, a therapsid and unrecognizable parts of amphibians and/or reptiles. Additionally, hair-like structures found in one coprolite specimen occur as diagenetically altered (oxide-replaced) structures and moulds (or partly as pseudomorphs) in a microcrystalline carbonate-fluoride-bearing calcium phosphate. This suggests that the latest Permian therapsids probably were equipped with hair-like integument or hairsuit. If true, this is by far the oldest evidence of this mammalian character in the stem group of mammals.