Ichnology

Different kinds of Paramoudras, cannonballs and related concretions in sandstone of Eocene age are described. The Paramoudras adopt spherical, subcylindrical, serpent and sponge shapes, and aggregate masses or magmas, with odd designs. These concretions present conspicuous tubular drillings and structures. Their morphology and spatial development are described on the basis of field observations and experimental sections. The ichnofossils of Paramoudras, probably of marine polychaetes, contain tubular drillings and structures with glauconite and magnesite. It is also probable the presence of iron and
manganese oxides. The concretions don’t have a concentric structure but their external cover may present Liesegang bandings. Several aspects about their origin, characteristics and bioichnology are discussed.

Spiral-shaped foraging trace fossils, assigned to the graphoglyptid cf. Spirorhaphe azteca, are reported from an Early Permian intertidal flat in the Robledo Mountains of southern New Mexico, USA. Remarkably similar spiral-shaped structures are produced in modern intertidal flats by the paraonid polychaete Paraonis fulgens, and function as traps to capture mobile microorganisms migrating in the sediment in response to tides. We envisage a similar function for the Early Permian trace fossils. Previous studies have suggested that the lack of P. fulgens–type traces from ancient intertidal deposits indicates that such behavior only evolved geologically recently in such settings. However, this report demonstrates that such specialized foraging behavior was present in intertidal settings by at least the Early Permian. Graphoglyptids are typical of deep-marine settings, and characteristic of the Nereites ichnofacies. This represents their first undoubted occurrence in intertidal facies in the geological record. We postulate that the occurrence of graphoglyptids in deep-marine and intertidal settings is related to the predictability of resources. The scarcity of intertidal graphoglyptids in the geological record is most likely a preservational effect.

Members of several insect orders are known to modify osseous vertebrate remains postmortem, whether for nutritional or habitational purposes. Recognizing the appearance of these taphonomic traces is important in the evaluation of skeletal remains recov- ered from forensic and archaeological contexts. Thus far, ants (Hymenoptera: Formicidae) have only been anecdotally noted in the litera- ture to modify bone as a presumed food resource and have not yet been shown to modify human bone. This paper presents a contemporary case where a colony of ants was directly observed nesting inside human bone and describes the appearance of modi ed entrances into their repurposed medullary cavity dwellings. This case may prompt further considerations of ants as agents of bone modi cation, how and why such behaviors occur, and how to recognize these ichnological traces.

The  rock  succession  belonging  to  Middle  Bhuban  Unit  of  Bhuban  Formation,  Surma  Group  (Lower  to  Middle Miocene)  is  the thickest  lithostratigraphic  unit  in  Mizoram.  A  ~120  m  thick  sequence  comprising  sandstone,  siltstone  and  shale  belonging  to  Middle
Bhuban Unit of Bhuban Formation, Surma Group along Bawngkawn-Edenthar road section in Aizawl, Mizoram is rich in trace fossils. This succession  has  yielded  23  ichnotaxa,  including  vertical  burrows,  horizontal  simple  burrows  and  trails,  horizontal  branched  burrows  and bilobate  structures.  Eight  ichnospecies  out  of  these  were  previously  described  and  the  remaining  16  are  being  described  for  the  first  time. These  ichnospecies  belong  to  6  ichno-assemblages,  namely,  Archaeonassa,  Ophiomorpha,  Palaeophycus,  Phycodes,  Skolithos  and
Thalassinoides. Occurrence of Skolithos, Cruziana and at places Skolithos-Cruziana ichnofacies suggests that the rocks of Middle Bhuban Unit  exposed  along  Bawngkawn-Edenther  section  were  deposited  under  high  energy  conditions  and  sandy  shifting  substrate  in  foreshore zone  and  unconsolidated,  poorly  sorted,  soft  substrate  and  low  energy  condition  in  the  shoreface  to  offshore  zone,  respectively.

La série mésocrétacée (Albien supérieur-Cénomanien inférieur) des monts des Ouled Naïl (Atlas saharien oriental, Algérie) est représentée par des alternances marno-calcaires qui sont caractérisées par une bioturbation modérée à faible. Cette dernière comprend Gyrolithes isp., Oichnus isp., Planolites isp., Skolithos isp., Thalassinoides isp., T. paradoxicus Woodward, 1830, T. suevicus Rieth, 1930 et Tisoa siphonalis de Serres, 1840. L'ichnoassemblage enregistré ici est représenté par des traces d'habitat (domichnia), de nutrition (fodinichnia) et de prédation (praedichnia), produites essentiellement par des crustacés décapodes, des vers (surtout des polychètes) et des gastéropodes naticidés. Il reflète les ichnofaciès à Skolithos et à Glossifungites. Aussi, les terriers de Thalassinoides paradoxicus et la trace bioérosive (boring) Oichnus sont enregistrés pour la première fois en Algérie. Sédimentologiquement, quinze (15) faciès-types ont été décrits et interprétés sur le plan environnemental. Les données sédimentologiques et l'évolution verticale des traces fossiles corroborent un milieu marin très peu profond à influence tidale dans la partie basale de la série, qui est caractérisée par l'abondance des trois ichnoespèces de Thalassinoides et par la présence des séquences loféritiques. Un approfondissement a eu lieu dans la partie centrale de la série, marquée surtout par la dominance des calcaires micritiques, la rareté de la faune benthique et la présence de la trace bioérosive Oichnus. L'étude sédimentologique de la partie sommitale de la série suggère un environnement marin peu profond, soumis à l'action des vagues de tempêtes et de marées, indiqué par la fréquence des figures sédimentaires (HCS, SCS, laminations entrecroisées…) et des traces fossiles qui supportent des conditions pareilles (ex. Skolithos isp., Tisoa siphonalis).

Lower Cretaceous trackways assignable to xiphosurids were recently found in tidally influenced marginal-marine deposits of the Agrio Formation (Patagonia, Argentina). The aim of this paper is to describe these trace fossils in detail, discuss their conditions of preservation, make palaeoecological and taphonomic inferences from them, and analyse the importance of their palaeogeographic location. These trace fossils are assigned to Kouphichnium, and five track morphotypes are established. Microbially induced sedimentary structures (MISS) are associated with the trackways. Scanning electron microscope (SEM) studies document the involvement of microbial mats in the preservation of the trackways by the presence of cyanobacteria-like filament sheaths. The microbial mats enabled preservation of the tracks by binding and biostabilisation of the sediment surface. The mostly likely producers of the trackways are from the subfamily Limulinae. The studied surface could represent a high-tide mating ground associated with a very shallow water deposit on a warm Cretaceous tidal flat. These records are the first convincingly documented trackways produced by xiphosurids in the Early Cretaceous worldwide and the second fossil record of this group from the Cretaceous in the Southern Hemisphere

The  combination  of  archaeoentomological  and  forensic  analyses,  known  as  "Funerary Archaeoentomology", yields important new insights into our knowledge of past burial practices: secondary body handling, taphonomy of the grave, delayed burial, grave reopening and anthropogenic
mummification processes. After a detailed review of the sampling methods for insect remains retrieval, diagnostic identification criteria for the archaeoentomofauna are provided for a better understanding and interpretation of grave taphocenosis. The second part of this paper highlights
how the ichnological approach, namely the study of trace fossils present on bones and on some various exogenous materials present in the grave, proved to be an efficient new tool to improve our knowledge of pre- and post-depositional taphonomic processes.

Dinosaur tracks are biogenic, sedimentary structures and not body fossils or biological objects in the common sense. They result from the complex interaction of the kinematics of the trackmaker, its foot anatomy, and the substrate properties, and from taphonomic processes acting prior to the incorporation of the tracks into the sedimentary record. The objective of this work is an interdisciplinary study of a large sample of dinosaur tracks and trackways linking sedimentology with vertebrate ichnology, palaeontology, and palaeoecology.

Excellent conditions are provided by the Late Jurassic (Kimmeridgian) Chevenez—Combe Ronde tracksite, which is one of several tracksites located on the future course of the Transjurane highway near Porrentruy (Canton Jura, NW Switzerland). Here, eight superimposed dinosaur track-bearing surfaces were systematically excavated level-by-level within a 0,65 m thick laminite interval, unearthing almost 1400 dinosaur tracks. The main track level, located at the base of the interval, is the most diverse ichnoassemblage composed of 14 trackways of tiny (Pes Length < 25 cm) and small (25 cm < PL < 50 cm) sauropods and 43 trackways of minute (PL < 10 cm), small (10 cm < PL < 20 cm), and medium-sized
(20 cm < PL < 30 cm) bipedal, tridactyl dinosaurs.

The main issues are: (1) identification of true tracks, undertracks, and overtracks, and their relationships with substrate properties, their link with the exposure index, and their utility in the reconstruction of the palaeoenvironment; (2) implications of the main track level ichnoassemblage for dinosaur behaviour, the terrestrial palaeoecosystem, and vertebrate ichnofacies; (3) relationships between variability in trackway patterns and configurations with locomotion speed, behaviour, and substrate properties as well as implications for locomotion capabilities; (4) Quantification and relevance of sauropod trackway gauge; and (5) interpretation of manus-dominated and pes-only sauropod trackways.

The approach is first actualistic by studying human footprints and processes acting during their formation and preservation on modern tidal-flats. In these highly structured environments, microbial mats are ubiquitous, strongly facies-specific, and occupy a key position during and after footprint formation. Undertracks readily form in biolaminated sediment, whilst underprints and deep tracks are common in unlaminated, water-saturated sediment. Most consolidated vertebrate tracks are affected by taphonomic processes, including renewed and/or repeated growth of microbial mats leading to the formation of modified true tracks, internal overtracks (track fills), and overtracks.

The sauropod tracks and the encasing laminite interval of the Combe Ronde site are then subject of detailed sedimentological and taphonomical analyses. This discloses the sediment properties at the time of track formation and reveals the processes modifying the tracks during subaerial exposure and integrating them into the sedimentary record. Track morphology, associated track features, and sedimentary features can be linked with the exposure index, identifying the palaeoenvironment as a supratidal flat not located in close proximity to a coastline. These flats were susceptible for track recording only during short periods after wetting due to a rainy period or due to occasional storms. Longer periods of subaerial exposure prior to burial are indicated by the presence of internal overtracks and/or overtracks, and rapid covering up is indicated by the lack of overtracks on top of tracks with large displacement rims. Cross-sections of sauropod tracks provide insight into the consolidation history of the substrate prior to track formation and into the walking dynamics of dinosaurs, confirming that sauropods put their hindfeet in a pronounced plantigrade way on the ground.

The level-by-level superimposition of the studied surfaces enables to identify true tracks, undertracks, and overtracks. The best-defined true tracks (anatomical morphotypes) of the main track level are then used for ichnotaxonomy and trackmaker identification, and the detailed analyses of trackway parameters, including trackway gauge, provide insight into the locomotion capabilities of dinosaurs.

The best-defined minute and small tridactyl tracks can be assigned to the ichnogenus Carmelopodus, extending it from the Middle Jurassic into the Late Jurassic. These tracks were likely left by a small theropod dinosaur similar in size to Compsognathus or Juravenator. The medium-sized tridactyl tracks of morphotype II exhibit some of the typical features of the ichnogenus Therangospodus (attributed to large and robust theropods) but also some of ornithopod ichnotaxa.

The sauropod trackways show a wide range of patterns and configurations but are all medium- to wide-gauge. Therefore, they are assigned tentatively to the ichnogenus Brontopodus attributed to derived “brachiosaurid” or “titanosaurid” dinosaurs. The variability of the trackways reflects the general locomotion capabilities of the trackmakers and is an expression of individual walking style and behaviour, which may be related to substrate properties. Trackway patterns (the degree of manus overprinting by the pes) and different trackway configurations including trackway gauge are not only related to locomotion speed, and they provide no evidence of a relationship with ontogeny.

The gauge of sauropod trackways can be quantified with the pes trackway ratio and the here defined [WAP/PL]-ratio (Width of the pes Angulation Pattern / Pes Length). Gauge is possibly related to the substrate and the behaviour of the trackmaker adapting to it, but this does not change the overall medium-gauge to wide-gauge appearance of the trackways. The manus-dominated and pes-only sauropod trackways of the Combe Ronde site are explained by trackmakers exerting more pressure on the manus than the pes, and by overprinting of the manus by the pes, respectively.

The alignment of trackways on the main track level shows no evidence of a nearby shoreline and of interactions between the different groups of dinosaurs. It indicates gregarious behaviour amongst tiny and small sauropods, and suggests that minute and small bipedal dinosaurs were frequent visitors on the supratidal flats.

The ichnoassemblage of the main track level is the first one found in the Jura Mountains displaying abundant minute and small tridactyl tracks. This is also typical for the other Ajoie ichnoassemblages, which further exhibit tracks of tiny to large (up to 1,1 m PL) sauropods, and tracks of medium-sized to large (up to 0,8 m PL) bipedal dinosaurs. Sauropod trackways include narrow-gauge and wide-gauge trackways indicating the presence of “basal” and derived sauropods. This suggests that dwarfed insular animals can be excluded as trackmakers of the tiny and small sauropod trackways of the Ajoie ichnoassemblages and the Combe Ronde tracksite and that the Jura carbonate platform was connected with the landmasses of the London-Brabant Massif and the Massif Central during periods of emersion. Dinosaurs used the Jura carbonate platform for the establishment of in situ, predominantly saurischian dinosaur populations, but also as a migration corridor between the massifs.

Because the Ajoie ichnoassemblages are dominated by small tridactyl tracks, they differ from other Jurassic tetrapod ichnofacies in carbonate settings, notably from the Brontopodus ichnofacies. In the case of those ichnoassemblages commonly attributed to the Brontopodus ichnofacies, the lack or rareness of small tridactyl tracks may indicate the absence of small trackmakers in those palaeoenvironments or unsuitable conditions for the formation and preservation of small tracks.

This study highlights the benefits of systematic and interdisciplinary analyses of dinosaur tracks, which disclose variations related to behaviour and to differences in substrate. This allows recognizing anatomical morphotypes and trackway configurations representative of typical trackmaker behaviour. The latter can then also be used in ichnotaxonomical classification. Similar approaches should be in the focus of future work and performed on the other tracksites and ichnoassemblages of the Ajoie. Together with the evidence from other tracksites of the Jura Mountains, this will contribute towards a better understanding of the terrestrial palaeoenvironments and palaeogeography, and of dinosaur palaeoecology and palaeobiogeography on the Jura carbonate platform.

The Messinian diatomaceous deposits are widely exposed in the Lower Chelif Basin (NW-Algeria). The upper part of the Diatomaceous Formation is intercalated by four diatomaceous beds rich in Zoophycos and Chondrites. Both these traces were produced by the members of endo-benthonic fauna adapted to nutrient exploitation within sediments. In the Diatomaceous Formation, larger dark-coloured Chondrites targionii cross-cuts smaller C. in-tricatus, which could indicate ecological succession perhaps due to conditions getting less oxygenated and causing the need for larger burrows. Size increase of Zoophycos upwards in the section may indicate that environment became less stressed, shallower and likely had a higher nutrient content or alternatively there was a change in the trace-maker biological affinity. The depositional environment shows some evidence of low-oxy-genated to dysoxic conditions, because abundant Chondrites occurs without any other trace fossils with the exception of Zoophycos. Chondrites trace-makers likely maintained a connection to oxygenated water but penetrate into anoxic sediments rich in sulfides or ammonium that are required for microbe-breeding and feeding. Most likely studied Zoophycos-Chondrites and pure Zoophycos associations of the Upper Member of the Diatomaceous Formation are of deeper shelf origin. The diatomaceous volcanic ash beds of the upper part of the formation are intensively bioturbated by a horizontal network of large-size Thalassinoides, which represents domichnial and fodinichnial structures, and suggesting an enough oxygenated environment with sufficient nutrients. Thalassinoides level likely represents shallower water conditions (shallow shelf) than the underlying levels characterised with Zoophycos-Chondrites and Zoophycos associations.

The remarkably extensive and abundant Mesozoic-aged exposures on public lands around Moab have made this region well known for ichnofossils. The nearly complete record of Upper Triassic through Lower Cretaceous rocks exposed in this area is well known for its sheer abundance of tracks and traces. This three-day field trip will visit many important classic and new sites exposed in the Bureau of Land Management’s Canyon Country District. This field trip guidebook will give one an overview of the major sites we will visit, as well as a brief summary of work previously done in these areas.

Fosil jejak merupakan hasil dari proses jejak-jejak makhluk hidup yang telah terbentuk pada sedimen yang belum terkompaksi. Berdasarkan hasil penelitian fosil jejak dapat sebagai penciri dari kebiasaan makhluk hidup pembentuknya. Pada pengamatan yang tedapat di sungai banyumenng banyak terdapat fosil jejak sehingga kita dapat menggamati dengan baik dan juga dapat kita temukan dibatuan sedimen karena hasil jejak jejak tersebut tersedimentasi dan bahkan terisi oleh mineral- mineral. Dan kesimpulan bahwa dalam kita mempelajari ichnofosil ini berarti kita menandakan bahwa adanya aktifitas makhluk hidup yang terjadi pada jaman dahulu yang dimana aktifitas mahkluk hidup tersebut diakibatkan oleh organisme yang membentuk jejak jejak makhluk hidup. Fosil jejak yang terdapat pada sungai banyumeneng berada pada persilangan lanau dan pasir yang menandakan formasi kerek.

Phycosiphon-like trace fossils are some of the most common and important ichnofabric forming trace fossils in marine facies characterized by fine-grained sediments such as mudstones and siltstones. This study aims to reconstruct the three-dimensional morphology of Phycosiphon-like trace fossils from three locations
of different geological age in order to test the validity of criteria used to recognize such fossils in vertical cross section. It also presents methodology to create digital volumetric models of trace fossils which geometry was computer-modeled using series of consecutive images obtained by serial grinding and measured in 3D software.

Organism-substrate interactions and their products – biogenic structures – are important biosignatures on Earth. This study discusses the application of ichnology – the study of organism-substrate interactions – to the search for present and past life beyond Earth. Three main questions are addressed: (1) Why to look for biogenic structures (i.e. traces and ichnofabrics) beyond Earth? (2) What biogenic structures to expect on other planets, moons and asteroids? (3) How to study extraterrestrial biogenic structures? Review of terrestrial evidence highlights a set of properties that make traces and ichnofabrics important for the search of potential extraterrestrial life: trace fossils preserve the activity of soft-bodied organisms; biogenic structures are resilient to processes that obliterate other biosignatures (i.e. mechanical and chemical degradation , diagenesis, tectonism and metamorphism); traces are very visible biosignatures; traces indicate environment and behaviour; traces can be universal biosignatures, i.e., biosignatures ideally suited for detecting any type of life. A model of organism-substrate interactions beyond Earth is here proposed. Expected extraterrestrial traces are those that manifest behaviours that allow to maintain homeostasis: excavations, meandering traces and biodeposition structures. Most of the existing rovers and orbiters provide basic instruments for searching these traces. It is here suggested that the search for extraterrestrial biogenic structures by rovers would also benefit from artificial adjustable lighting, GPR, LiDAR, and drilling equipment with optical televiewer. In this study, open-access databases of rover and orbiter imagery have been searched for traces and ichno-fabrics, but no unquestionable evidence of biogenic structures beyond Earth has been found besides those produced by humans. This sounds along the lines of the famous Fermi Paradox: if the universe is teeming with aliens, where are their traces? Results of this search show that habitable environments are not the only place to look for biogenic structures; non-habitable environments such as moons without atmosphere can favour the preservation of shallow-tier traces. The better preservation potential of traces compared to other biosignatures greatly widens the issue of planetary protection, including the interaction between astronauts or vehicles and the substrate may produce disturbances. Although this study highlights a new direction of study with the tools and concepts of ichnology, dialogue MARK between the astrobiological and ichnological communities is needed to use its full potential and possibly answer one of the major questions of science: Does life exist beyond Earth?

Dinosaur tracks in Portugal are known from Bajocian-Bathonian (Jurassic) through middle Cenomanian (Cretaceous) rocks. The Portuguese track record includes two outstanding Middle Jurassic track sites both in Central W Portugal: the Vale de Meios track site, showing dozens of parallel theropod trackways, and the Galinha site, where several long sauropod trackways can be seen. There are two other major areas with important dinosaur track sites: SW Algarve (S Portugal), Lower Cretaceous, and the Sesimbra region (Central W Portugal), Upper Jurassic-Lower Cretaceous. Huge track sites such as the Vale de Meios and Galinha sites can not be excavated and removed into museums; therefore, they must be preserved in situ, to be studied and visited in their original geological context. Track sites such as these are important not only for their scientific, ichnological, significance; they are also valuable for science popularization and to stimulate public interest for the preservation of the geological/palaeontological heritage. In Portugal, in 1996 and 1997, five dinosaur track sites have been declared natural monuments. In such sites it is possible to teach and show Palaeontology, as well as other aspects of Earth sciences in their original geological context, to children from different school levels and to a broad public with different scientific backgrounds. Educational programmes for school children and the general public are paramount in order to elucidate them about dinosaurs and their tracks, but also to improve their attitude towards the scientific and cultural value of this palaeontological ichnoheritage. Educational activities are essential to the success of geoconservation. They boost public awareness, which, in turn, is fundamental for the protection and valorisation of the geological and palaeontological heritage. When local communities are conscious of the scientific and cultural value of the natural heritage in their home region they become proud of it and this fact dramatically increases the odds of its effective protection. Nevertheless, up until now the Galinha track site is the only Portuguese track site prepared to receive visitors and to offer them palaeontological educational programmes.

Tetrapod swim tracks attributed to reptiles occur abundantly throughout Lower to Middle Triassic deposits across the western United States. In central and southern Utah these swim track localities are stratigraphically restricted to the upper portion of the Torrey Member of the Moenkopi Formation. Here they show detailed features such as longitudinal striae and disc-shaped claw impressions that must have required specific substrate conditions in order to be produced and preserved. A suite of sedimentologic and ichnologic observations at several swim track localities demonstrates the widespread development and persistence of subaqueous firmground substrates buried by crevasse splay deposits in the interdistributary areas of a large lower delta plain. The heterolithic stratigraphy is typical of interdistributary bays and channels and generally consists of decimeter-scale fining-upward cycles of mud- and siltstone beds below the track-bearing horizons and thicker, massive or cross-bedded sandstones above. Siltstone and sandstone beds show low angle accretion sets, vary laterally in thickness, and commonly pinch out so that they cannot be correlated regionally. Common sedimentary structures indicate predominately quiet subaqueous conditions with periodic higher energy events. These include trough cross stratification, climbing ripples, rip-up clasts, and soft sediment deformation. Track surfaces often exhibit localized dewatering structures and load casts in addition to flute casts and current crescents indicating unidirectional current flow. Mudcracks are rare. The low diversity invertebrate ichnoassemblage is comprised of locally high densities of relatively diminutive traces and reflects stressed brackish water faunas. These characteristics are almost certainly augmented by delayed biotic recovery following the end-Permian mass extinction and resulted in extremely low degrees of bioturbation. This lack of biogenic mixing promoted semi-consolidation of dewatered mud substrates resulting in the widespread production and persistence of firmgrounds capable of recording and maintaining detailed swim tracks. The subsequent burial of these firmground surfaces under coarser-grained crevasse splay deposits resulted in sharp heterolithic contacts further facilitating the preservation of detailed track features.