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Dinosaur trackway studies provide valuable insights into extinct animals' locomotor behaviour. Despite limitations arising from the inability to directly observe these trackmakers, speed and gait estimation formulae have become standard tools in the field of dinosaur ichnology. Stride length has traditionally been used to estimate dinosaur average speed and intra-trackway speed variations, but its unilateral focus can overlook some nuances within trackways. Alternatively, the contralateral measure pace length may not always align with the direction of travel. Analysing data from the Mancheon-ri tracksite and others, our results show that step length aligns advantageously along the trackway axis and captures nuanced speed variations. Incorporating additional parameters such as cadence and step duration enriches our understanding of the trackmaker's movements. Cadence summarises the overall rhythm of movement across trackways, and step duration reveals temporal variations between individual steps, offering potential for 3D animated reconstructions of dinosaur behaviour. Despite these methodologies' inherent limitations and assumptions, they provided a more refined understanding of dinosaur locomotion and behavioural patterns. Acknowledging the limitations of studying unobservable trackmakers, our estimations – based on established formulas for hip height and speed – are both rooted in accepted methodologies and remain informative, enhancing our understanding of dinosaur trackmaker behaviours. [ABSTRACT FROM AUTHOR]

Sauropods were a successful group of herbivorous dinosaurs that colonised all continents throughout the Mesozoic. At first glance, the organisms in this group present a conservative shape of quadrupedal animals with elongated necks and tails. However, there was great diversification in the morphology of sauropods, which is still poorly understood in detail, especially during the Early Cretaceous. In this study, we describe a new ichnosite dated from the earliest stages of the Cretaceous of Brazil. The site includes a well-preserved trackway of a large sauropod dinosaur, with manus and pes prints, as well as tracks of theropods and indeterminate tetrapods. The sauropod trackway shows a unique set of characteristics that allowed the erection of a new ichnogenus and ichnospecies, Sousatitanosauripus robsoni igen. nov. et isp. nov. The probable trackmaker was a Titanosauriformes with a mosaic of basal and advanced features, bringing new insights into the diversity and evolution of the group. [ABSTRACT FROM AUTHOR]

The Upper Cretaceous Cantwell Formation in Denali National Park and Preserve (DENA) preserves an abundant and diverse ichnofossil record of high latitude dinosaurs. Field-based investigations of the formation remain limited due to its wide areal extent and remoteness, leaving questions concerning its temporal and faunistic relationships to other units unaddressed. Here we describe the largest tracksite known in DENA and all of Alaska – a 7500 square metre outcrop of steeply dipping beds known as the Coliseum. The site exposes 66.3 metres of vertical section consisting of laterally extensive fine- to medium-grained sandstone, mudstone, calcareous shale, and bentonite. Vertebrate trace fossils include true tracks, transmitted tracks, natural casts, and trackways documented via handheld and UAV-assisted photogrammetry, enabling three-dimensional mapping of the site. Facies analysis reveals a depositional environment of crevasse splay and overbank deposits within a fluvial floodplain. U-Pb dating of bentonite collected from the site returned an age of 69.3 ± 0.9 Ma, improving the limited temporal constraints of the formation. We document several ichnotaxa, some new to the formation, representing ornithopods, ceratopsids, and large and small-bodied avian and non-avian theropods. The Coliseum provides a rare window into a high latitude, Late Cretaceous forested ecosystem deposited in a Greenhouse World. [ABSTRACT FROM AUTHOR]

Aratichnus, new ichnogenus, is described from a lower Eocene-aged, tidally reworked sandstone unit (Baronia Formation) near Baronia de Sant Oïsme, Spain. Aratichnus n. igen. is a horizontal, epichnial furrow ranging from simpler forms that display repeating straight to gently curved grooves to more complex serial furrows paralleling each other. Two new ichnospecies are described, Aratichnus hordeicollis n. isp. and Aratichnus apricuscampus n. isp., that encompass the range of morphological variability exhibited by the ichnogenus. A. hordeicollis exhibits ordered, repeating shapes of furrows, while A. apricuscampus exhibits furrows which do not repeat in shape and direction. We interpret Aratichnus n. igen. as a trace fossil made by an interface deposit feeder exploiting a patchy food source in an intertidal environment. [ABSTRACT FROM AUTHOR]

Omission surfaces represent a gap in the sedimentary record on a particular environment, constituting an important tool for basin analyses. Nevertheless, not always these surfaces constitute key sequence-stratigraphic surfaces, and their correct interpretation is highly important for the recognition of genetically related strata. Documentation and interpretation of ichnological data from stratigraphic surface can refine the sedimentological model. The Puesto El Moro Formation (lower Upper Cretaceous) in the Austral-Magallanes Basin, southern Patagonia (Argentina), shows excellent examples of several omission surfaces stacked during a transgressive context associated with the beginning of the foreland stage. Each of these surfaces, interpreted as Tidal Ravinement Surfaces, contain Thalassinoides isp. and Sinusichnus isp., which represent opportunistic colonization by crustaceans into a predominantly firm substrate. In this case study, the vertical recurrence of substrate-controlled trace fossil suites is the result of high-frequency repeated coastal conditions during the transgression; the associated surfaces, which have limited lateral extension, have low potential for correlation at basin scale. [ABSTRACT FROM AUTHOR]

Recognizing stratigraphically important bounding surfaces relies on assessing the facies that juxtapose these surfaces as well as the trace fossil omission suite associated with the surface. The ability to differentiate between purely transgressive surfaces and those that conceal earlier stratigraphic surfaces that allude to a more complex history of development regarding the identification of allogenic surfaces of sequence stratigraphic significance that might have otherwise been overlooked. This study analyzes four examples of transgressive surfaces of erosion from Cretaceous-aged strata, with three of the examples representing a TSE/SB (amalgamated transgressive surface of erosion with a sequence boundary) that mask earlier base level falls. Consideration of variable omission suites along depositional strike and dip highlights the influence of substrate rheology on the nature of omission suites. In this study we demonstrate marked changes in the omission suite along bounding surfaces along proximal to distal trends that arise due to changes in underlying rheology. Finally, detailed core analysis is shown to be an imperative asset to subsurface investigation to address the limitations of using wireline well data alone in identifying stratigraphically important surfaces for more accurate regional mapping and characterization of transgressive surfaces. This study highlights that many stratigraphically important surfaces such as those that correspond to a TSE/SB may go unnoticed if utilizing wireline data alone. Overall, this study provides a comprehensive approach to further understanding and identifying transgressive surfaces in the rock record, especially those that demarcate a more complex history other than simple transgressive ravinement. [ABSTRACT FROM AUTHOR]

Bioerosion traces are a powerful tool for reconstructing benthic paleo-communities through the geological record. The late Quaternary marine deposits of Patagonia (Argentina) are elongated ridges parallel to the present coast, rich in sand, gravel and shells, the latter being the main substrate for bioerosion traces. However, the ichnological studies in the Quaternary are scarce in high latitudes of the Southern Hemisphere. This work describes for the first time the bioerosion traces recorded in shells belonging to diverse taxa of mollusc from Quaternary deposits in Puerto Lobos, Southern of San Matias Gulf (Patagonia, Argentina). This study complements the scarce information on bioerosion traces in the Southern Hemisphere. A total of 710 mollusc shells were obtained from four Quaternary beach ridges at Puerto Lobos. As a result, 15 ichnotaxa were recorded for the first time in the site, 13 of them for the first time in the Holocene of San Matías Gulf. Through qualitative analysis, bioerosion patterns were observed in the late Quaternary of Puerto Lobos. The abundance of worm and sponge borings in the Pleistocene could be related to warm and sediment-free waters. On the contrary, the results of the bioerosion study in the Holocene and recent samples were very similar. This could indicate that the same environmental factor controlled both bioerosion patterns. For the Holocene, it was observed that the bioerosion pattern is mainly represented by trace produced by suspension and filter-feeding organisms, such as bryozoans, among others. Together with the increase in ichnodiversity, this could indicate an increase in nutrient availability in the San Matías Gulf associated with upwelling events. Therefore, our results reinforce the hypothesis proposed by previous authors that the upwelling events currently observed in the study area began during the mid-Holocene. [ABSTRACT FROM AUTHOR]

The Miocene succession (Allala River Sandstones and Tenes Blue Marls Formation) that crops out in the Tenes area, situated in the northeast of the Lower Chelif Basin in NW-Algeria, contains a low-diversity assemblage of trace fossils. Fifteen (15) ichnogenera were identified: Arenicolites, Beaconites, Cylindrichnus, Diplocraterion, Macaronichnus, Ophiomorpha, Palaeophycus, Parahaentzschelinia, Planolites, Rosselia, Skolithos, Taenidium, Teichichnus, Thalassinoides and Zoophycos. Ethologically, these ichnogenera chiefly display dwelling and feeding activities. The presence of thick, deep-tier, scattered, mainly vertical dwelling burrows attributed to the Skolithos ichnofacies indicates high energy conditions, normal oxygenation and soft substrate. Moreover, elements of the Cruziana ichnofacies show more varied behavioural strategies and higher inchnodiversity with the dominance of horizontal burrows of deposit-feeders. This ichnological study supports the palaeoenvironmental interpretation based on sedimentological analysis of a wave-dominated siliciclastic platform (backshore to offshore), allowing a more precise zonation of the shoreface zone (middle/upper and lower shoreface). In addition, this study allows evaluation of variable degrees of storm influence in response to the contrasting palaeogeomorphology of the coastline. [ABSTRACT FROM AUTHOR]

Eight fossil tetrapod footprints from lake-shore deposits in the Lower Jurassic Moenave Formation at the St. George Dinosaur Discovery Site (SGDS) in southwestern Utah cannot be assigned to the prevalent dinosaurian (Anomoepus, Eubrontes, Gigandipus, Grallator, Kayentapus) or crocodyliform (Batrachopus) ichnotaxa at the site. The tridactyl and tetradactyl footprints are incomplete, consisting of digit- and digit-tip-only imprints. Seven of the eight are likely pes prints; the remaining specimen is a possible manus print. The pes prints have digit imprint morphologies and similar anterior projections and divarication angles to those of Brasilichnium, an ichnotaxon found primarily in eolian paleoenvironments attributed to eucynodont synapsids. Although their incompleteness prevents clear referral to Brasilichnium, the SGDS tracks nevertheless suggest a eucynodont track maker and thus represent a rare, Early Mesozoic occurrence of such tracks outside of an eolian paleoenvironment. [ABSTRACT FROM AUTHOR]

Himatiichnus mangano igen. et isp. nov., a new trace fossil from the late Ediacaran Huns Member of the Urusis Formation, southern Namibia, comprises intertwining tubes exhibiting dual lineation patterns and reminiscent of both modern and early Cambrian examples of priapulid worm burrows. These similarities support the interpretation of a total-group scalidophoran tracemaker for H. mangano, thus providing direct evidence for the first appearance date of Scalidophora in the late Ediacaran ca 539 Ma. This new material is thus indicative of the presence of total-group scalidophorans below the Cambrian boundary and supports inference of a lengthy Precambrian fuse for the Cambrian explosion.

A dinosaur track was recently discovered at Buarcos (Figueira da Foz, Portugal). The stratigraphic level is in the upper part of the Boa Viagem Sandstone Formation, and the specimen is the first evidence for the presence of middle Kimmeridgian dinosaurs in the Cabo Mondego area. This track reveals a medium size theropod estimated with one meter height to the hip. Moderate dinoturbation indicate the presence of more than one dinosaur at that time. This finding suggests that Buarcos area may have a relevant ichnological fossil record, highlighting the importance of further works in this formation. It's also a good indicator for the presence of dinosaur remains which are poorly known in this time interval. Based on the currently known stratigraphic distribution of the theropod fossil record in the Upper Jurassic of the Lusitanian Basin, the trackmaker could have been either Ceratosaurus, Lourinhanosaurus or Allosaurus. The paleoenvironment is interpreted as a deltaic alluvial plain, with small to medium size migrating channels and flooding areas. The footprint has also didactic and aesthetic features which, on display in a museum, contribute to enhance cultural and educational activities. The context of the discovery of this specimen allows to address issues on the geological heritage. [ABSTRACT FROM AUTHOR]

In this study, the focus is directed towards terracotta building materials with "traces," which were disregarded as defective and unworthy of consideration until recently. Samples have been examined through the lens of ichnoarchaeology, revealing that every material unearthed has the potential to provide information about the past, support existing theories, or facilitate novel interpretations. A total of fifty-three samples from two ancient cities were analyzed in this study. The findings of this research support the scholars' thesis that the climatic conditions in Anatolia in the 2nd century AD were similar to those of today. Moreover, it was concluded that the environment surrounding the brick workshop in Aizanoi was markedly more severe compared to that of Perge. The examined traces also enabled certain evaluations concerning social life during the Ancient Period. [ABSTRACT FROM AUTHOR]

We propose a spit bar setting as the possible palaeoenvironment of the basal Late Cretaceous transgressive sequence in NW Bohemia. A new Cenomanian transgression model for the Bohemian Basin is also proposed. The uppermost Devět Křížů Sandstone, which has been conventionally referred to the Bohdašín Formation, probably represents the middle or lower upper Cenomanian (Upper Cretaceous), not the Triassic as previously supposed. We assume that this controversial unit was deposited before the main latest Cenomanian-early Turonian transgression. The spit bars were likely overgrown by vascular plants during their emergence in the late Cenomanian, and then inundated during the latest Cenomanian and early Turonian transgressive phases. The studied deposits had been intensively bioturbated, and the cf. Taenidium suite was recognized for the first time in them alongside the Thalassinoides assemblage (T. paradoxicus, T. suevicus, Thalassinoides isp., cf. Thalassinoides), which are characteristic of the Scoyenia and Glossifungites ichnofacies, respectively. The bioturbated, rhizolith-bearing horizon was presumably a paleosol. [ABSTRACT FROM AUTHOR]

Taxonomy is a dynamic and evolving scientific field in biological and paleontological research, which describes and systematises species and other taxa and thus lays the foundation to solve and structure biological questions. The study of past (fossil) and modern (present) seafloor traces holds huge potential for understanding the composition, behavioural ecology, and ecosystem impact of benthic communities, e.g., in terms of bioturbation and carbon cycling. In trace fossil research (paleoichnology), ichnotaxonomical analysis is based on the application of ichnotaxobases, morphology being the most important and useful criterion. However, marine neoichnological analyses (modern traces; lebensspuren) have no standardised ichnotaxobases. In the literature, classification based on morphological descriptions or behavioural assignations can be found, but without consensus. This lack of standardised terminology hinders comparisons among studies and regions. Through this manuscript, we discuss the limitations of marine lebensspuren characterisation through underwater observations and how further classification could be done (i.e., possible ichnotaxobases). Considering that most of the classifications will be based on marine still images, we propose a classification for marine lebensspuren based on a combination of three labels: 1) morphology (e.g., M-ridged trail), 2) behaviour determination (e.g., locomotion and feeding), and 3) tracemaker taxonomy (e.g., Echinocrepis rostrata). Accordingly, the classification will be 1) M-ridged trail 2) Locomotion and feeding 3) Echinocrepsis rostrata. A set of recommendations is given to address all three labels. Also, we describe some of the contrasting positions of paleo- and neoichnology, particularly where a solution presently seems difficult to find, and argue that open nomenclature could be useful as still images contain large amounts of information. Finally, we provide examples of the usage of this classification for input to a marine lebensspuren online repository and how this nomenclature can help to compare worldwide lebensspuren in a consistent way. [ABSTRACT FROM AUTHOR]

Impressions of vertebrate bodies or their parts, such as trace fossils and natural molds of bones, are a valuable source of information about ancient faunas which may supplement the standard fossil record based on skeletal elements. Whereas trace fossils of animal activity are relatively common and actively studied within the field of ichnology, and natural impressions of internal or external surfaces are a frequent preservation mode in fossil invertebrates, natural molds of bones are comparatively rare and less extensively documented and discussed. Among them, internal molds (steinkerns) of turtle shells are a relatively well-known form of preservation, but the mechanisms and taphonomic prerequisites leading to their formation are poorly studied. External shell molds are even less represented in the literature. Herein, we describe a historic specimen of a natural external turtle plastron mold from the Triassic (Norian) Löwenstein Formation of Germany–a formation which also yielded a number of turtle steinkerns. The specimen is significant not only because it represents an unusual form of preservation, but also due to its remarkably large size and the presence of a potential shell pathology. Although it was initially interpreted as Proterochersis sp., the recent progress in the knowledge of proterochersid turtles leading to an increase in the number of known taxa within that group allows us to verify that assessment. We confirm that the specimen is morphologically consistent with the genus and tentatively identify it as Proterochersis robusta, the only representative of that genus from the Löwenstein Formation. We note, however, that its size exceeds the size observed thus far in Proterochersis robusta and fits within the range of Proterochersis porebensis from the Grabowa Formation of Poland. The marks interpreted as shell pathology are morphologically consistent with Karethraichnus lakkos–an ichnotaxon interpreted as a trace of ectoparasites, such as leeches. This may support the previously proposed interpretation of Proterochersis spp. as a semiaquatic turtle. Moreover, if the identification is correct, the specimen may represent a very rare case of a negative preservation of a named ichnotaxon. Finally, we discuss the taphonomy of the Löwenstein Formation turtles in comparison with other Triassic turtle-yielding formations which show no potential for the preservation of internal or external shell molds and propose a taphonomic model for the formation of such fossils. [ABSTRACT FROM AUTHOR]

Extreme hypersaline environments are known to be challenging ecosystems for the survival of organisms. These extreme environments are characterized by high evaporation, resulting in a drastic reduction in the ichnological and bioturbational diversity. Moreover, such environments are poorly understood on account of limited documentation in rock records. The Great Rann of Kachchh forms an exclusive salt-encrusted geomorphic facet and is India's most extensive exposure to hypersaline deposits. The area is inundated by tidal ingress from the Arabian Sea during the monsoon, followed by an evaporative period. Moreover, tidal ingress in the Rann of Kachchh and its effect on the ecology ispoorly documented. Ichnological investigations of the hypersaline Great Rann of Kachchh revealed four recurring trace fossils, Arenicolites, Palaeophycus, Polykladichnus, and Skolithos, with annelids, and crustaceans as the most likely producers. Furthermore, the existence of their juvenile forms is indicated by the presence of small and tiny subsurface burrows. Hence, in the present research, we used ichnology to document the limit and mechanism of tidal ingress to demarcate the tidal inundation boundary up to the east of Khadir Island. We propose a hypothesis identifying the tidal inundation limit by larval recruits burrows and present an ichnological model for a hypersaline environment. [ABSTRACT FROM AUTHOR]

A slab with three tetradactyl avian footprints was excavated from the Agha Jari Formation (Mio-Pliocene) in the Zagros Mountains, southwest Iran, in the early last century and named as Urmiornis abeli. The name Urmiornis had been used for the didactyl bird fossil and ichnogenus name was later revised to Iranipeda. Validity of Iranipeda abeli has been discussed by authors in recent decades, and revision of the original material is necessary. Based on re-examination the holotype I. abeli reveals that this name is valid and it differs by long hallux, separate digit imprints and size of lateral digit II and IV traces with other large wading bird footprints. Iranipeda include three ichnospecies: I. abeli and I. millumi and I. intermedia by emended diagnosis of Iranipeda. Ciconiidae is the nearest track-maker candidate for Iranipeda. I. abeli type specimen has been collected from the lower part of the Agha Jari Formation and based on lithostratigraphic position and radiometric data, it is of Late Miocene age. [ABSTRACT FROM AUTHOR]

Eight fossil tetrapod footprints from lake-shore deposits in the Lower Jurassic Moenave Formation at the St. George Dinosaur Discovery Site (SGDS) in southwestern Utah cannot be assigned to the prevalent dinosaurian (Anomoepus, Eubrontes, Gigandipus, Grallator, Kayentapus) or crocodyliform (Batrachopus) ichnotaxa at the site. The tridactyl and tetradactyl footprints are incomplete, consisting of digit- and digit-tip-only imprints. Seven of the eight are likely pes prints; the remaining specimen is a possible manus print. The pes prints have digit imprint morphologies and similar anterior projections and divarication angles to those of Brasilichnium, an ichnotaxon found primarily in eolian paleoenvironments attributed to eucynodont synapsids. Although their incompleteness prevents clear referral to Brasilichnium, the SGDS tracks nevertheless suggest a eucynodont track maker and thus represent a rare, Early Mesozoic occurrence of such tracks outside of an eolian paleoenvironment.

This paper presents explication on how paleontologists reconstruct the past using fossils when good modern analogues are not available. I call these pastist methods to differentiate them from presentist methods in which such analogues are available. I do so by presenting two fossil cases: the problematica and graphoglyptids. I describe a forgotten heuristic, "analogue chaining," that involves jumping from fossil anomaly to fossil anomaly using one to make sense of the other in successive fashion, using the relations between fossils to guide reconstruction. I relate this to the philosophy of historical sciences in four ways. First, that methods like analogue chaining have a "linearity" meaning that there are limited ways in which to learn about specimens using analogues. Second, that they are intrinsically difficult to notice, i.e. invisible. Third, that linearity and invisibility put pressure on some accounts of optimism about historical sciences. Fourth, our cases provide novel forms of optimism based on epistemic enhancement: the phenomena that some questions regarding an event are better answered millions of years after its occurrence. [ABSTRACT FROM AUTHOR]

An association between round or oval features and linear features has been noted in South African Pleistocene coastal deposits, in apparent association with elephant tracks. The round or oval features sometimes exhibit concentric rings, and the latter often comprise near-parallel grooves and ridges. In one case the concentric rings and parallel grooves are closely connected. Such an association requires interpretation, even if this remains hypothetical until further sites are identified. Elephants are the heaviest extant land mammals, and their capacity to impart substantial forces onto the substrates on which they tread is well documented. Such forces include a seismic component, and seismic communication between elephants has received considerable attention in recent decades. Comparisons with dinosaur tracks are instructive in interpreting the available ichnological evidence. In the absence of plausible alternatives, the possibility that the noted features represent an ichnological signature of elephant seismicity or seismic communication needs to be considered. The rock art record in southern Africa suggests that ancestral humans were aware of elephant seismic communication. A comprehensive approach to elephant seismicity can involve not just research into the habits of extant elephants, but also the rock art record and the trace fossil record. To illustrate these concepts, findings from South African trace fossil sites and rock art sites are presented. [ABSTRACT FROM AUTHOR]

This commentary critiques a scientific paper on the fossil flora of the Azores, pointing out inaccuracies and inconsistencies. The authors dispute the claim that there are no fossil plants on certain islands and provide evidence to the contrary. They also highlight errors in geological maps, taxonomic determinations, and descriptions of geological formations. The critique emphasizes the need for more accurate research, including detailed photographic evidence and replication of results. The authors encourage further study but urge improvements in taxonomy, geological descriptions, and evidence presentation. [Extracted from the article]

The sedimentary basins in the Continental Rift of Southeastern Brazil (CRSB) provide an opportunity for ichnological analyses due to its well-known facies relationships and paleoenvironmental interpretations. This study reports invertebrate trace fossils from the Neogene fluvial deposits (Floriano Formation) and applies integrated ichnological and facies analyses to reconstruct the environmental conditions recorded in this lithostratigraphic unit. Fieldworks revealed a rich ichnofauna in the Floriano Formation, whose facies associations have been interpreted as indicative of meandering river environments. Four sedimentary facies were identified, including bioturbated sandstone, horizontally stratified sandstone, laminated sandstone, and mudstone. Six ichnogenera were identified, Arenicolites, Beaconites, Camborygma, Palaeophycus, Skolithos, and Taenidium. Those ichnogenera occur as Skolithos, Taenidium, and Beaconites ichnocoenoses. The Skolithos ichnocoenosis is primarily represented within sand bar deposits, indicating arthropod colonization in abandoned channels. The Taenidium ichnocoenosis, which is observed within mudstone layers and presents Camborygma burrows, suggests transitional environments between aquatic and subaerial conditions, locally with high water table levels. The Beaconites ichnocoenosis indicates changes in substrate consistency associated with progressive desiccation and extended exposure time. Therefore, the identified ichnocoenoses, combined with the analysis of physical sedimentary structures, suggest generally humid conditions during colonization by invertebrates of the meandering river deposits of the Floriano Formation. [ABSTRACT FROM AUTHOR]

Integrated sedimentological and ichnological studies in deltaic systems are key to determine whether a delta is river‐dominated, tide‐dominated, wave‐dominated or hybrid, and thus predict the distribution of their geometries and main reservoirs. The Austral Basin is one of the most important oil and gas basins from Argentina, and the Upper Cretaceous La Anita Formation has shown excellent attributes as a hydrocarbon reservoir. Analysis of eleven cores, supplemented by a large volume of well logging data and two‐dimensional and three‐dimensional seismic, allowed to recognize a river‐dominated deltaic system affected by hyperpycnal discharges and storm events. Four main facies associations were recognized (offshore, prodelta, delta front and interdistributary bay), being the delta front facies associations, the most recurrent facies and constituting the major reservoir of the La Anita Formation. Three types of deltaic mouth bars have been characterized in the delta front. Type I corresponds to active mouth bars with preservation of sedimentary structures and bioturbated by suspension and deposit feeding organisms. Type II represents the stopped progradation and the abandonment in the construction of mouth bars, which are completely reworked by suspension and deposit feeding organisms and, in some cases, affected by fair‐weather or storm‐wave processes at the top. Type III comprises hyperpycnal mouth bars characterized by transitional and recurrent intervals of sedimentary structures, high concentration of phytodetritus, and paucity of bioturbation. The amalgamation and coalescence of these three types of sandy mouth bars produce lobe‐like geometries and are the main processes of delta front construction and progradation. This proposed model allows to explain the principal mechanism of construction of the delta front and can be applied to the analysis of other reservoirs where mouth bar architectural elements are dominant. [ABSTRACT FROM AUTHOR]

A purported cemented sand sculpture found in Pleistocene aeolianite deposits on the Cape south coast of South Africa resembles a stingray (minus a tail) in outline. Symmetry is evident in the rock's shape and the pattern of grooves on its surface. It is postulated that it may be a three-dimensional example of representational art of another species. Optically stimulated luminescence studies of rocks in the vicinity indicate that it dates to the Middle Stone Age, most probably during Marine Isotope Stage 5 (when high sea levels imply a nearby coastline). The correspondence in shape between the purported sand sculpture and the blue stingray (Dasyatis chrysonota) suggests that it may have been traced from a fresh specimen. Tracings on sand are postulated as a possible 'stepping stone' between abstract early palaeoart and representational rock art. Features of the rock suggest that the creation of a stingray sand sculpture may conceivably have been followed by symbolically wounding it and amputating its lethal end. Identification of further ammoglyphs will be important in refining the analysis of this newly identified form of early palaeoart. [ABSTRACT FROM AUTHOR]

Following various assignments to Archaeocyatha, worm tubes, and finally incertae sedis, the enigmatic Ediacaran–Cambrian taxon Archaeichnium haughtoni has in recent years come to represent somewhat of a wastebasket taxon to which the indeterminate tapering tubular forms common across this interval are assigned. This 'catch‐all' status has been aided in part by both suboptimal specimen photography and the temporary loss of the holotype after its second redescription in 1978. Recent rediscovery of the A. haughtoni holotype in the collections of the Iziko South African Museum in Cape Town has enabled a much‐needed re‐assessment of this critical and cryptic taxon, with results suggesting that this material from the latest Ediacaran or earliest Cambrian of Namibia is among the earliest fossil record examples of marine worm burrow linings, and the oldest examples of linings robust enough to withstand exhumation and current transport. These traces indicate the emergence of this important animalian ecosystem engineering behaviour closer to the Ediacaran–Cambrian boundary than previously thought. [ABSTRACT FROM AUTHOR]

The Upper Red Formation has extensive outcrops in the southern and western parts of the Zanjan province, northwestern Iran. Here, we studied a sequence of lowermost part of this formation near Mehr)Abad village, northwestern Zanjan. Lithostratigraphy, sedimentology and ichnology of the URF have been studied in recent decades but palynology of this formation has not been investigated. This article is a preliminary report of miospores. The palynofloras comprise thirty species including three algae spores (in three genera), seven fern species (in seven genera), various type of gymnosperm (thirteen species designated to nine genera), and angiosperm pollen species (seven species designated to six genera); for example, Botryococcus sp., Closteritetrapidites magnus, and Diagonalites diagonalis of algal spores; Echinatisporis muelleri, Magnastriatites sp. cf. M. grandiosus, and Polyapodiaceoisporites potoniei of fern; Cathayapollis scheuringii, Cedripites sp., Ephedripites tertiarius, Pinuspollenites spp., Cupressacites spp., Tsugapollenites spp. of gymnosperm, and Acidanthera brevicollis, Calliandra spp., Fagopsis longifolia, Monoporopollenites sp., and Retitricolporites sp. of angiosperm evidenced herein. Moreover, botanical affinity of miospores considered. Therefore, Botryococcaceae/ Dictyosphaeriaceae, Closteriaceae, Zygnemataceae (algae); Marattiaceae, Pteridaceae, Polypodiaceae (fern); Cupressaceae, Ephedraceae, Pinaceae (gymnosperm), and Fagaceae, Fabaceae, Iridaceae, and Poaceae (angiosperm) identified. [ABSTRACT FROM AUTHOR]

A new ichnospecies of the ichnogenus Nummipera Hölder, 1989 has been documented in the carbonate packstone and wackestone of the Ypresian (early Eocene) Naredi Formation from the western Kutch (Kachchh) Basin, India. This new ichnospecies is distinguished from Nummipera eocenica (the existing sole ichnospecies of ichnogenus Nummipera) on the basis of the burrow orientation, taxonomy and orientation of foraminifera lining the burrow walls, and burrow filling. Nummipera saraswatii isp. nov. represents the earliest occurrence of Nummipera. It is a horizontal to gently inclined, straight to feebly curved, intermittently vertically flattened tubular burrow closed at one end, displaying circular to elliptical cross-sections, and representing three-distinct morphotypes. The analyzed specimens are characterized by walls mostly lined with unbroken and well-sorted megalospheric tests of Assilina laxispira. Burrows are characterized by active massive fill akin to the host material consisting of organic-rich muddy material and bioclasts or active concentric fill displaying a distinct outer and inner lumen, filled with organic-rich materials of different grain-sizes varying from mud to sand. Crustaceans and vermiform animals can be envisaged as the probable producers based on the distinctive morphotypes and ethological affinity. The shallow-tier N. saraswatii shows association with the deep-tier Cylindrichnus concentricus. The association manifests key features of a stressed Cruziana Ichnofacies and characterizes an Assilina bank of a proximal carbonate open shelf setting. [ABSTRACT FROM AUTHOR]

The Buda Formation is a coccolith-rich carbonate unit deposited in lagoonal waters of the Comanche Shelf during the early Cenomanian. This unit constitutes a long-lived hydrocarbon reservoir and an important regional marker in the Texas Gulf Coast Basin. Several sedimentological and stratigraphic studies have been carried out on this formation but debates regarding its depositional conditions persist. The Buda Formation is characterized by a high degree of bioturbation intensity; however, comprehensive ichnological analyses focused on elucidating its depositional conditions have not been performed yet. Here, we report the Buda Formation ichnofauna comprising twenty ichnotaxa and widely dominated by Thalassinoides isp. and Chondrites isp. The ichnological analysis allowed us to recognize nine ichnofabrics, which reflect changing palaeoecological and palaeoenvironmental conditions during the deposition of this unit. In general, the different ichnofabric expressions throughout this formation reflect fluctuating levels of exchange of waters between the Buda lagoon and the open sea, based on the inherent changes in physicochemical parameters, such as oxygenation levels and salinity. In addition, the concept of taphonomic pathways is underscored for accuracy in palaeoecological reconstructions, as well as the need for integrating diagenetic processes, particularly when applying this concept to carbonate rocks. [ABSTRACT FROM AUTHOR]

In most oxygen-deficient ancient successions, Chondrites and Zoophycos are typical and recurrent trace fossils that are the last to disappear during deoxygenation events. Here, we report an unusual case of an oxygen-deficient ichnofauna lacking Chondrites and showing scarce Zoophycos, from the Upper Jurassic-Lower Cretaceous Vaca Muerta Formation of Argentina. One outcrop and cores from nine wells were analysed. The succession comprises fine-grained, mixed carbonate-siliciclastic deposits accumulated in marginal-marine, basin, drift, slope, and outer ramp environments. It displays abundant biodeformational structures mostly producing irregular-laminated and massive fabrics in fine to medium mudstone. However, discrete trace fossils can be found within interbedded coarser-grained intervals, namely (in order of decreased ichnogen- era abundance), Teichichnus, Alcyonidiopsis, Coprulus, Phycosiphon, Planolites, Lockeia, Thalassinoides, Palaeophycus, Nereites, Crininicaminus, Zoophycos, Diplocraterion, and ?Skolithos. Considering all ichnotaxa, the Vaca Muerta Formation may be seen as hosting a relatively diverse ichnofauna, yet, this is misleading because most occurrences are of low diversity. This atypical ichnofauna may be explained by either a lack of strong seasonality and existence of background food-rich environments, or by salinity variations, precluding the specialized feeding style of the Chondrites and Zoophycos producers. The dominance of feeding trace fossils with spreite (Teichichnus) and the low ichnodiversity suggest that the studied ichnofauna belongs to the Zoophycos Ichnofacies. [ABSTRACT FROM AUTHOR]

Abstract The sedimentary basins in the Continental Rift of Southeastern Brazil (CRSB) provide an opportunity for ichnological analyses due to its well-known facies relationships and paleoenvironmental interpretations. This study reports invertebrate trace fossils from the Neogene fluvial deposits (Floriano Formation) and applies integrated ichnological and facies analyses to reconstruct the environmental conditions recorded in this lithostratigraphic unit. Fieldworks revealed a rich ichnofauna in the Floriano Formation, whose facies associations have been interpreted as indicative of meandering river environments. Four sedimentary facies were identified, including bioturbated sandstone, horizontally stratified sandstone, laminated sandstone, and mudstone. Six ichnogenera were identified, Arenicolites, Beaconites, Camborygma, Palaeophycus, Skolithos, and Taenidium. Those ichnogenera occur as Skolithos, Taenidium, and Beaconites ichnocoenoses. The Skolithos ichnocoenosis is primarily represented within sand bar deposits, indicating arthropod colonization in abandoned channels. The Taenidium ichnocoenosis, which is observed within mudstone layers and presents Camborygma burrows, suggests transitional environments between aquatic and subaerial conditions, locally with high water table levels. The Beaconites ichnocoenosis indicates changes in substrate consistency associated with progressive desiccation and extended exposure time. Therefore, the identified ichnocoenoses, combined with the analysis of physical sedimentary structures, suggest generally humid conditions during colonization by invertebrates of the meandering river deposits of the Floriano Formation.

Abstract Storm‐flood‐dominated deltas are sedimentary systems in which a complex interplay of hydrodynamic processes occurs during storms (e.g. tropical cyclones) due to the coeval action of continental and oceanic processes. This paper reports on a superbly exposed, 135.5 m thick stratigraphic succession of the Pleistocene Cholan Formation exposed along the Da'an River, Taiwan. The sedimentary succession comprises alternating mudstone and sandstone, is mostly fine‐grained, and exhibits multiple event beds that record deposition during tropical cyclones and post‐depositional deformation features produced during earthquakes. Detailed facies analyses reveal that deposition towards the base of the succession occurred in the palaeo‐Taiwan Strait in storm‐flood‐dominated prodelta and delta‐front environments passing upwards into delta‐plain environments. Tropical cyclone beds are encountered throughout the subaqueous storm‐flood delta successions, and are identified by (i) trough cross‐stratified sandstone bedsets with erosive bases that contain both mud clasts and mudstone beds, (ii) sandstone with aggrading wave ripples and (iii) hummocky cross‐stratified sandstone with rare gutter casts filled with coal fragments and shell remains. Tropical cyclone deposits are either top‐down burrowed or capped by massive or laminated mudstone. Seismites are rare and are mainly recognised through soft‐sediment deformation of beds; they do not show evidence of slope failure. Compared to storm‐flood delta successions described elsewhere, the Cholan Formation shows significantly fewer oscillatory‐generated sedimentary structures and gutter casts. This difference is attributed to the Cholan Formation being deposited in and along the margin of a strait characterised by strong shore‐parallel currents and relatively small storm waves due to its position between Taiwan and mainland China. This study refines depositional process interpretations of the Cholan Formation, provides criteria for recognising storm‐flood delta deposits in tectonically active straits with multiple sediment sources fed by steep drainages and short river catchments, and provides additional criteria for recognising tropical cyclone deposits in shallow‐marine settings.

The lower Maastrichtian chalk of the Isle of Rügen was deposited in a pelagic setting in the aphotic zone. Its rich fossil content has attracted research attention for centuries, whereas its ichnological characteristics remain poorly understood, even though horizons with intense bioturbation and occurrences of trace fossils in flint are common. The enhanced colour contrast of smooth chalk faces reveals repeated phases of benthic colonisation; larger burrows are commonly subject to silicification, while flint nodules also can preserve burrows in chalk. A total of 37 ichnogenera, including 47 ichnospecies of bioturbation and bioerosion trace fossils have been recognised; these are here briefly described, in addition to indeterminate material. Many ichnotaxa are recorded for the first time from the Rügen chalk. Bioerosion is restricted mainly to local hardgrounds in the form of biogenic components (such as shells and belemnite guards).

The stratigraphic framework in the southern portion of the Paraná Basin, represented by the Devonian System strata, preserves a rich fossil deposit. This deposit is marked by the presence of a paleofauna commonly referred to as endemic, composed of benthicorganisms from the Malvinocaffric Realm. The present study constitutes the interpretation of a new depositional section, and for this purpose, the new areas were visited in the field and described in terms of facies, ichnology, and taphonomy. The research resulted in the interpretation of facies from a marine environment influenced by storms in a situation of ecological stress established immediately before the Kačák extinction event

Zagros Mountains in the southwest Iran was created by the closure of the Neo-Tethys and collision of Arabian and Eurasian plates. The Fars Group (Miocene to Pliocene) formed during this collision. The Agha Jari Formation (upper Miocene- lower Pliocene) is uppermost rock unit of the Fars Group, which has high potential for terrestrial vertebrate ichnology. This formation mostly deposited in the continental environment and a section of the formation studied in the east Gotvand, north Khuzestan province, southwest Iran. Agha Jari Formation, includes alternations of sandstone, siltstone, and marl in red to brown colour layers in the studied section. Numerous vertebrate footprints have been reported from the middle part of the formation in Gotvand section, among which artiodactyl footprints are abundant and diverse. Re-examination of artiodactyl footprints led to the discovery of a new ichnogenus and ichnospecies, Pazhanipeda kiyani, characterised by small-sized didactyl hooves, asymmetric and gracile imprints, and a wide interdigital angle. Based on the comparison of size, morphology and asymmetry of digit imprints with artiodactyl hooves, goats were considered as track makers of Pazhanipeda kiyani. [ABSTRACT FROM AUTHOR]

Trace fossils record the interactions between organisms and their surroundings, and can therefore provide unique insights into the coevolution of trace makers and the environment. However, identifying the producers of trace fossils is challenging because different animals can create very similar traces and many ichnotaxa can therefore only be attributed to broad morphological grades. For example, simple horizontal traces like Gordia are generally suggested to have been produced by vermiform organisms, potentially encompassing a range of animal phyla. This uncertainty makes it difficult to decipher their palaeobiological significance through major evolutionary events and episodes of environmental change. We have developed new mathematical approaches for identifying previously unrecognized signatures left by the trace makers of simple marine locomotory traces. We calculated the deviation angle series of self‐crossing traces made by extant isopods, polychaetes, gastropods and nematodes, computing the frequency spectrum and autocorrelation function in each case. The results reveal that each of these taxa left unique markers during the trace‐making process, reflecting differences in their anatomy and locomotory behaviour. We were able to identify the possible trace makers of several early Palaeozoic Gordia specimens, demonstrating that ichnospecies within the same ichnogenus can be created by distantly related animals with very different morphologies and/or behaviours. This novel mathematical framework has great potential for identifying the possible producers of diverse trace fossils through deep time, helping to uncover the earliest evidence of certain animals or behaviours. It also has great potential for quantifying ichnotaxonomy, consolidating the link between ichnology and palaeobiology. [ABSTRACT FROM AUTHOR]

The Gansfontein palaeosurface (Fraserburg, Karoo, South Africa), which is correlated with the stratigraphic lowermost part of the continental Middle–Upper Permian Teekloof Formation, is revisited. This treasure trove of peculiar and exquisitely preserved sedimentary structures and invertebrate and vertebrate traces serves as a document of a set of fluvial paleoenvironments ranging from small ponds to marginal lacustrine and muddy riverine outer banks. It represents an isolated and relatively small "oasis" within the dominating sedimentary environments of the Teekloof Formation characterized by fine and medium-grained siliciclastics related to repeated higher-energy flooding events. The vertebrate traces include abundant therapsid trackways and, locally, tetrapod swimming traces. Tetrapod footprints show a very variable preservation in different areas of the palaeosurface, and it also changed based on the time of impression. Fish trails (Undichna) are relatively common. The invertebrate ichnofauna is comprised of abundant arthropod traces and horizontal burrows; however, the palaeosurface was not intersected by intense bioturbation. The occurrence of this scenario of abundant life reflects complex interaction among different tracemakers with the substrate and is evidence of a relatively quiet palaeoenvironment, which was suddenly submerged and sealed during a flooding event. Sedimentological and ichnological insights from such a palaeosurface, therefore, opens a rare window into Middle Permian ecosystems in southernmost Gondwana. [ABSTRACT FROM AUTHOR]

Tooth-marked bones provide important evidence for feeding choices made by extinct carnivorous animals. In the case of the dinosaurs, most bite traces are attributed to the large and robust osteophagous tyrannosaurs, but those of other large carnivores remain underreported. Here we report on an extensive survey of the literature and some fossil collections cataloging a large number of sauropod bones (68) from the Upper Jurassic Morrison Formation of the USA that bear bite traces that can be attributed to theropods. We find that such bites on large sauropods, although less common than in tyrannosaur-dominated faunas, are known in large numbers from the Morrison Formation, and that none of the observed traces showed evidence of healing. The presence of tooth wear in non-tyrannosaur theropods further shows that they were biting into bone, but it remains difficult to assign individual bite traces to theropod taxa in the presence of multiple credible candidate biters. The widespread occurrence of bite traces without evidence of perimortem bites or healed bite traces, and of theropod tooth wear in Morrison Formation taxa suggests preferential feeding by theropods on juvenile sauropods, and likely scavenging of large-sized sauropod carcasses. [ABSTRACT FROM AUTHOR]

Storm‐flood‐dominated deltas are sedimentary systems in which a complex interplay of hydrodynamic processes occurs during storms (e.g. tropical cyclones) due to the coeval action of continental and oceanic processes. This paper reports on a superbly exposed, 135.5 m thick stratigraphic succession of the Pleistocene Cholan Formation exposed along the Da'an River, Taiwan. The sedimentary succession comprises alternating mudstone and sandstone, is mostly fine‐grained, and exhibits multiple event beds that record deposition during tropical cyclones and post‐depositional deformation features produced during earthquakes. Detailed facies analyses reveal that deposition towards the base of the succession occurred in the palaeo‐Taiwan Strait in storm‐flood‐dominated prodelta and delta‐front environments passing upwards into delta‐plain environments. Tropical cyclone beds are encountered throughout the subaqueous storm‐flood delta successions, and are identified by (i) trough cross‐stratified sandstone bedsets with erosive bases that contain both mud clasts and mudstone beds, (ii) sandstone with aggrading wave ripples and (iii) hummocky cross‐stratified sandstone with rare gutter casts filled with coal fragments and shell remains. Tropical cyclone deposits are either top‐down burrowed or capped by massive or laminated mudstone. Seismites are rare and are mainly recognised through soft‐sediment deformation of beds; they do not show evidence of slope failure. Compared to storm‐flood delta successions described elsewhere, the Cholan Formation shows significantly fewer oscillatory‐generated sedimentary structures and gutter casts. This difference is attributed to the Cholan Formation being deposited in and along the margin of a strait characterised by strong shore‐parallel currents and relatively small storm waves due to its position between Taiwan and mainland China. This study refines depositional process interpretations of the Cholan Formation, provides criteria for recognising storm‐flood delta deposits in tectonically active straits with multiple sediment sources fed by steep drainages and short river catchments, and provides additional criteria for recognising tropical cyclone deposits in shallow‐marine settings. [ABSTRACT FROM AUTHOR]

The Horseshoe Canyon Formation has provided a wealth of vertebrate skeletal fossils over the past 100 years of collection. Vertebrate trace fossils such as footprints and trackways, however, have been markedly underrepresented. Trackways can provide a wealth of information regarding behaviour and soft tissues reflective of autopodial anatomy. Discovery of several giant, high-fidelity ichnites in series from the Morrin Member represents the first definitive dinosaur trackway reported from the Horseshoe Canyon Formation. The trackway is composed of three footprint casts in series, alongside 22 associated ichnites. The ichnites were formed in soft sediment molds along a non-uniform walking surface. The deep substrates allowed for the preservation of both the plantar surface and dorsal components of the trackmakers' feet. Some ichnites show soft tissue morphologies like interdigital webbing, toe pads, and skin impressions. Presence of these features and small kidney-shaped forelimb prints allow referral to Hadrosauropodus langstoni. The preservation of the trackway demonstrates asymmetries useful for comparison of the relief and impression surfaces of prints using both discrete and morphometric characteristics, improving confidence in identifying partial or isolated Hadrosauropodus prints of various modes of formation. [ABSTRACT FROM AUTHOR]

The Quaternary vertebrate paleontology of the Brazilian Intertropical Region is well-known, but there are only a few publications on bone ichnology. In this paper, we analyzed trace fossils in 23 bones of the Gruna das Três Cobras, Complexo Suíço, and F3 caves, which are located in Bahia and Rio Grande do Norte states, in the Brazilian Intertropical Region. We discovered gnaw marks assigned to Machichnus and bite marks attributed to Nihilichnus, as well as insect modifications referring to single (Cuniculichnus, Gunnellichnus, Karethraichnus, and Osteocallis) and multiple behaviors (Munitusichnus, and Taotieichnus). Additionally, we proposed the new ichnospecies Nihilichnus sulcatus n. isp. (bite mark) and Cuniculichnus cascudoi n. isp. (insect feeding mark). Regarding the predation/scavenger marks, Protocyon troglodytes was the probable primary modification agent, but some traces may also be attributed to Smilodon populator and Caiman latirostris. Cuniculichnus, Karethraichnus, Munitusichnus, and Osteocallis are attributed to dermestids, whereas termites probably produced Gunnelichnus and Taotieichnus. [ABSTRACT FROM AUTHOR]

Twelve new avian ichnosites have been identified on South Africa's Cape south coast, adding to the 29 sites previously identified. More than half of these 41 avian ichnosites are found along a 9-km stretch of coastline east of Still Bay. The new sites provide the first southern African trace fossil records of the dove, stork and heron families, as well as a possible ostrich trackway and evidence of probable ostrich eggshell fragments. They buttress the previous inference of large avian chronospecies during the Pleistocene. The preponderance of large- and mediumsized tracks can be attributed to a bias whereby fossil tracks of larger, heavier birds are easier to recognise and interpret. Four of the longest fossil avian trackways ever to be identified occur within a 350-m stretch of coastline in the Driefontein area, east of Still Bay. The new findings provide an enhanced picture of the Pleistocene avifauna of the region. Many of the new sites are fragile and have limited prospects to endure, emphasising the need to document them through photogrammetry, and to regularly explore the coastline in high-yield areas in search of further sites. [ABSTRACT FROM AUTHOR]

Tracking technologies have revolutionized zoological research in recent decades; however, technologically simple methods of tracking spoor should not be removed from the researcher's arsenal. Tracking spoor, or field signs, is an old human skill, considered to be fundamental to our evolution as an intelligent species. It comprises finding and categorizing footprints, droppings and other animal-related signs, such as trampled paths and nests. Zoologists have been using traditional tracking methods as research tools for many years and still use them today. Tracking is being used mainly in the fields of animal behaviour and conservation. In animal behaviour studies, tracking is an important tool to measure behavioural responses while in conservation efforts, tracking is often an effective survey method compared to other methods. In this paper, we briefly review the history of tracking in human culture and zoology and present the different uses and methods of tracking employed in behavioural studies and wildlife surveys. We discuss the advantages and disadvantages of the methods and present the conditions required for each method to be effectively applied. Our main goal is to encourage researchers to use spoor tracking, as it is reliable, easy and cheap to use and can be incorporated with modern methods to gain otherwise unachievable information. • Tracking spoor is an ancient skill which may have had a role in human evolution. • It is not an outdated method, despite technological advancements. • We review the different implementations of tracking spoor in zoological research. • We suggest how spoor tracking can be combined with modern technologies. • We hope this paper will inspire researchers to incorporate tracking in their studies. [ABSTRACT FROM AUTHOR]

Despite the absence of cuttlefish in Aotearoa New Zealand waters, cuttlebones and cuttlebone fragments have been reported and collected in the country since the early twentieth century. Not all could be reliably identified. As such, here we review all cuttlebone material collected from New Zealand shores available in natural history collections, as well as literature and online records. Species were identified, through morphological features and, for the first time, DNA barcoding, as: the Australian endemic Sepia apama Gray, 1849 (and possibly S. grahami A. Reid, 2001) and the widely distributed Indo-Pacific S. latimanus Quoy & Gaimard, 1832. In addition, the predation/scavenging marks (praedichnia) left on the cuttlebones by other organisms are assigned to four major types and attributed to albatrosses, sharks, and dolphins. The successful extraction of DNA from cuttlebones has potential future applications, including the examination of type specimens, since species were described based only on cuttlebones. [ABSTRACT FROM AUTHOR]

Polychaetes, echinoids and gastropods have been proposed as tracemakers for Bolonia Meunier, an elongate positive epirelief trace fossil characterized by two lobes composed of biserial, subtriangular pads and a mostly heart‐shaped cross‐section. Here, the internal structure and micromorphology of Bolonia are described for the first time using serial thin sections from shallow‐marine Lower Cretaceous intervals of the Agrio Formation (Neuquén Basin, Argentina). In vertical thin sections, a conical structure of variable width extends centrally from the base to the top of the trace. In horizontal thin sections, grains are reoriented and reworked, forming a central zigzag structure. The organic matter and clays form grain aggregates representing the internal structure of individual pads of the trace fossil. The sediment has mostly been reoriented, with grains making up subcircular pods. We interpret the central conical structure as the collapse of the medial zone of the trace fossil, which could have destroyed drain tubes, especially in the absence of early cementation. Studying horizontal thin sections, we reconstruct the diagnostic biserial pads as biserial concave structures. These are interpreted as backfilling structures produced by the aboral and lateral spines of irregular echinoids, which worked together to compact the sediment anteroposteriorly and moved alternatively, explaining the zigzag pattern in the menisci. We propose Spatangoidea or Cassiduloidea (or a closely related group) with a similar burrowing ability and spine movement as tracemakers of these Bolonia specimens. [ABSTRACT FROM AUTHOR]

Abstract An enigmatic transition from the storm‐dominated, offshore to lower shoreface deposits of the Redwater Shale Member (Sundance Formation) to the overlying mixed tidal and aeolian Windy Hill Sandstone (Morrison Formation) in the Oxfordian of the North American Western Interior has long been a source of intrigue. Previously proposed drivers include the progradation of a large, tide‐dominated delta onto a storm‐dominated shelf, a complete reorganisation of the basin's hydrodynamics and climate, or the development of a regional unconformity (termed the J‐5). In south‐eastern Wyoming, the Redwater Shale is characterised as an offshore to distal shoreface deposit with glauconitic siltstones and sandstones punctuated by coquinoid and sandy tempestites and hosting a Cruziana Ichnofacies. The Windy Hill Sandstone, a time‐transgressive, sand‐rich, intertidal succession with classic Pteraichnus and stressed Skolithos Ichnofacies, sharply overlies the Redwater Shale and records an abrupt basinward shift in facies that accompanied at least tens of metres of sea‐level fall. New, detailed sedimentological, ichnological and architectural data collected across this transition in the study area provide fresh insights into the depositional history of these units and demonstrates the existence locally of a composite J‐5 unconformity. The unconformity developed as tectonically driven, prograding shoreline trajectories of the Redwater Shale gave way to degrading trajectories of the Windy Hill Sandstone, leading to a forced regression and formation of a regressive surface of marine erosion. The sharp juxtaposition of intertidal flat facies (Pteraichnus Ichnofacies) directly upon offshore to lower shoreface deposits (Cruziana Ichnofacies) is the key to recognising the unconformity and proves the value of the previously underutilised ichnological data.

Tooth-marked bones provide important evidence for feeding choices made by extinct carnivorous animals. In the case of the dinosaurs, most bite traces are attributed to the large and robust osteophagous tyrannosaurs, but those of other large carnivores remain underreported. Here we report on an extensive survey of the literature and some fossil collections cataloging a large number of sauropod bones (68) from the Upper Jurassic Morrison Formation of the USA that bear bite traces that can be attributed to theropods. We find that such bites on large sauropods, although less common than in tyrannosaur-dominated faunas, are known in large numbers from the Morrison Formation, and that none of the observed traces showed evidence of healing. The presence of tooth wear in non-tyrannosaur theropods further shows that they were biting into bone, but it remains difficult to assign individual bite traces to theropod taxa in the presence of multiple credible candidate biters. The widespread occurrence of bite traces without evidence of perimortem bites or healed bite traces, and of theropod tooth wear in Morrison Formation taxa suggests preferential feeding by theropods on juvenile sauropods, and likely scavenging of large-sized sauropod carcasses.

Because almost all marine trace fossils were produced in underwater settings such as shoreface, offshore, continental shelf, slope, trench, and abyssal plain, investigating their modern analogues in these settings is important. In this discussion, I delve into a range of recent developments in the field of underwater neoichnology, concentrating on both my own contributions and those of fellow researchers. These advancements have been achieved through investigations conducted in various underwater settings, spanning from shallow coastal waters to the depths of the ocean floor. Our research methods have involved SCUBA diving as well as participation in submersible scientific expeditions. [ABSTRACT FROM AUTHOR]

When and where did humans first fashion footwear? Ichnology holds the potential to answer this unresolved question in palaeoanthropology. The global record of sites from which shod-hominin tracks have been considered is sparse. Consideration of proxies for footwear use, in conjunction with areas of known Middle Stone Age/Middle Paleolithic hominin tracksites, suggests two suitable regions in which to search for shod-hominin tracks of this age: southern Africa and Western Europe. Inhabitants of these areas in the Middle Stone Age would have had the means, motive and opportunity to fashion footwear. Ichnological evidence from three palaeosurfaces on South Africa's Cape coast, in conjunction with neoichnological study, suggests that humans may indeed have worn footwear while traversing dune surfaces during the Middle Stone Age. The hominin track record may be biased towards identification of tracks made by barefoot individuals, therefore the development of criteria for the identification of shod-hominin tracks should aid in future interpretation efforts. [ABSTRACT FROM AUTHOR]

The identification of presumed tetrapod tracks is not always unequivocal. Other sedimentary structures have been repeatedly mistaken for tracks, including other trace fossils such as arthropod tracks, burrows and fish feeding traces; erosional features; and human-made traces. We here review instances of difficult, ambiguous, or controversial cases that have been discussed in the literature. We then discuss four main criteria for the verification of tetrapod tracks: (1) preservation of regular trackway morphology, (2) preservation of track morphology, (3) deformation structures (best seen in cross-section) and (4) the temporal or environmental context. Of these criteria, criterion 1 is the most unambiguous and has rarely been challenged. We apply these criteria to a new site located within the city of Al-Bireh, Palestine, which belongs to the Lower Cretaceous (Albian) Soreq Formation. The site preserves a surface with many indistinct depressions that lack anatomical detail. Two unequivocal trackways are identified per criterion 1, demonstrating the first known occurrence of dinosaur fossils in Palestine. The tracksite is part of the late Lower Cretaceous carbonate platform of the eastern Levant, demonstrating temporal emergence of the platform above sea level and a connection to the mainland. [ABSTRACT FROM AUTHOR]