A trace fossil, also known as an ichnofossil, is a fossil record of biological activity by lifeforms but not the preserved remains of the organism itself. Trace fossils contrast with body fossils, which are the fossilized remains of parts of organisms' bodies, usually altered by later chemical activity or mineralization. The study of such trace fossils is ichnology and is the work of ichnologists.
Protichnites is an ichnogenus of trace fossil consisting of the imprints made by the walking activity of certain arthropods. It consists of two rows of tracks and a medial furrow between the two rows. This furrow, which may be broken, set at an angle, and of varying width and depth, is thought to be the result of the tail region contacting the substrate.
Zoophycos is a somewhat cosmopolitan ichnogenus thought to be produced by moving and feeding polychaete worms.
The Dakota is a sedimentary geologic unit name of formation and group rank in Midwestern North America. The Dakota units are generally composed of sandstones, mudstones, clays, and shales deposited in the Mid-Cretaceous opening of the Western Interior Seaway. The usage of the name Dakota for this particular Albian-Cenomanian strata is exceptionally widespread; from British Columbia and Alberta to Montana and Wisconsin to Colorado and Kansas to Utah and Arizona. It is famous for producing massive colorful rock formations in the Rocky Mountains and the Great Plains of the United States, and for preserving both dinosaur footprints and early deciduous tree leaves.
Skolithos is a common trace fossil ichnogenus that is, or was originally, an approximately vertical cylindrical burrow. It is produced by a variety of organisms in shallow marine environments globally and appear as lineated features in sedimentary rocks.
Rhizocorallium is an ichnogenus of burrow, the inclination of which is typically within 10° of the bedding planes of the sediment. These burrows can be very large, over a meter long in sediments that show good preservation, e.g. Jurassic rocks of the Yorkshire Coast, but the width is usually only up to 2 cm, restricted by the size of the organisms producing it. It is thought that they represent fodinichnia as the animal scoured the sediment for food.
Beaconella is an ichnogenus comprising a wide trace thought to be constructed by a burrowing arthropod ploughing through the sediment for food, leaving a mound of piled sediment at the end of each trace.
Radulichnus is an ichnogenus of trace fossil which resembles the marks produced by the action of a mollusc's radula on sediment. As an ichnogenus, its classification is based solely on appearance, and does not necessarily imply anything of the affinity of the organism which produced the trace. However, fossils of Kimberella have been found at or near the ends of Radulichnus traces, leading to the possibility that some traces were made by Kimberella.
Spirorhaphe is an ichnogenus of spiraling burrows. It is associated with the Nereites ichnofacies, which is interpreted as an indicator of deep-sea, pelagic, turbidity current-dominated systems. It is one of the most common graphoglyptid traces found in modern ocean beds.
Kouphichnium is an ichnogenus that has been attributed to limulids. Kouphichnium fossils resemble the footprints of birds, sometimes in conjunction with a medial line, and were initially thought to be bird or pterosaur tracks. The footprints are now believed to be the imprints of specialized limulid appendages, called pushers, terminating in four plates, used to push against the sediment. The medial line is left by the animal's telson. This ichnogenus is registered in the Carboniferous to the Cretaceous, in marine marginal environments in Tennessee, the United States and in Poland, as well as non-marine environments of Argentina and England, among others. The genus contains five species, K. arizonae, K. cordifomnis, K. lithographicum, K. minusculum and K. walchi.
The Höganäs Formation is a Late Triassic to Early Jurassic geologic formation in Skåne, Sweden. The formation is mostly known for its incredible flora collection from the Bjuv member, composed of over 110 species, and also includes several vertebrate remains, such as fishes, amphibians and dinosaur tracks & remains, although none have yet been referred to a specific genus.
Komlosaurus is an ichnogenus of theropod dinosaur from the Early Jurassic of Baranya, Hungary. The type species, Komlosaurus carbonis, was described by Kordos in 1983. The type remains come from the Mecsek Coal Formation, from the Middle Hettangian to the Early Sinemurian, and comprise several footprints.
Chondrites is a trace fossil ichnogenus, preserved as small branching burrows of the same diameter that superficially resemble the roots of a plant. The origin of these structures is currently unknown. Chondrites is found in marine sediments from the Cambrian period of the Paleozoic onwards. It is especially common in sediments that were deposited in reduced-oxygen environments.
Paleontology in Colorado refers to paleontological research occurring within or conducted by people from the U.S. state of Colorado. The geologic column of Colorado spans about one third of Earth's history. Fossils can be found almost everywhere in the state but are not evenly distributed among all the ages of the state's rocks. During the early Paleozoic, Colorado was covered by a warm shallow sea that would come to be home to creatures like brachiopods, conodonts, ostracoderms, sharks and trilobites. This sea withdrew from the state between the Silurian and early Devonian leaving a gap in the local rock record. It returned during the Carboniferous. Areas of the state not submerged were richly vegetated and inhabited by amphibians that left behind footprints that would later fossilize. During the Permian, the sea withdrew and alluvial fans and sand dunes spread across the state. Many trace fossils are known from these deposits.
Paleontology in Utah refers to paleontological research occurring within or conducted by people from the U.S. state of Utah. Utah has a rich fossil record spanning almost all of the geologic column. During the Precambrian, the area of northeastern Utah now occupied by the Uinta Mountains was a shallow sea which was home to simple microorganisms. During the early Paleozoic Utah was still largely covered in seawater. The state's Paleozoic seas would come to be home to creatures like brachiopods, fishes, and trilobites. During the Permian the state came to resemble the Sahara desert and was home to amphibians, early relatives of mammals, and reptiles. During the Triassic about half of the state was covered by a sea home to creatures like the cephalopod Meekoceras, while dinosaurs whose footprints would later fossilize roamed the forests on land. Sand dunes returned during the Early Jurassic. During the Cretaceous the state was covered by the sea for the last time. The sea gave way to a complex of lakes during the Cenozoic era. Later, these lakes dissipated and the state was home to short-faced bears, bison, musk oxen, saber teeth, and giant ground sloths. Local Native Americans devised myths to explain fossils. Formally trained scientists have been aware of local fossils since at least the late 19th century. Major local finds include the bonebeds of Dinosaur National Monument. The Jurassic dinosaur Allosaurus fragilis is the Utah state fossil.
Tanytrachelos is an extinct genus of tanystropheid archosauromorph reptile from the Late Triassic of the eastern United States. It contains a single species, Tanytrachelos ahynis, which is known from several hundred fossil specimens preserved in the Solite Quarry in Cascade, Virginia. Abundant fossils of Tanytrachelos are found in a series of lakebed sediments that were deposited over the course of about 350 thousand years in a lake which existed approximately 230 million years ago. Some fossils are very well-preserved and include the remains of soft tissues. Tanytrachelos is the most likely trackmaker of the ichnogenus Gwyneddichnium.
Spreite, meaning leaf-blade in German is a stacked, curved, layered structure that is characteristic of certain trace fossils. They are formed by invertebrate organisms tunneling back and forth through sediment in search of food. The organism moves perpendicularly just enough at the start of each back-and-forth pass so that it avoids reworking a previously tunneled area, thereby ensuring that it only makes feeding passes through fresh, unworked sediment.
Alierasaurus is an extinct genus of caseid synapsid that lived during the early Middle Permian (Roadian) in what is now Sardinia. It is represented by a single species, the type species Alierasaurus ronchii. Known from a very large partial skeleton found within the Cala del Vino Formation, Alierasaurus is one of the largest known caseids. It closely resembles Cotylorhynchus, another giant caseid from the San Angelo Formation in Texas. The dimensions of the preserved foot elements and caudal vertebrae suggest an estimated total length of about 6 or 7 m for Alierasaurus. In fact, the only anatomical features that differ between Alierasaurus and Cotylorhynchus are found in the bones of the feet; Alierasaurus has a longer and thinner fourth metatarsal and it has ungual bones at the tips of the toes that are pointed and claw-like rather than flattened as in other caseids. Alierasaurus and Cotylorhynchus both have very wide, barrel-shaped rib cages indicating that they were herbivores that fed primarily on high-fiber plant material.
Cheliceratichnus, meaning trace of a chelicerate arthropod, is an ichnogenus erected for a body imprint discovered in the Lower Jurassic East Berlin Formation of Holyoke, Massachusetts. The specimen is now housed at the Springfield Science Museum, which is one of multiple museums on the Quadrangle. Considering that only a single specimen was found, the ichnogenus is monospecific, with the species name lockleyi honoring paleontologist and ichnologist Martin Lockley. In trace fossil classification schemes based on behavior, the body imprint is considered a cubichnion, or resting trace. Cheliceratichnus lockleyi exhibits the tagma characteristic of arthropods, with the trace divided into anterior, central, and posterior regions. Dalman and Lucas (2015) interpreted these regions as imprints of the chelicerae, prosoma, and opisthosoma, respectively, of a chelicerate arthropod. Additionally, imprints of the animal's legs and telson were identified. These authors noted that, in general, the pattern of the trace was similar to the body plan of the Solifugae, or camel spiders, but also noted that the presence of a telson imprint rules out that group because these animals lack telsons. Consequently, they attributed the trace to a solifuge-like arthropod without being more committal on what made it. In addition to the body imprint, the animal produced a trackway, called Acanthichnus cursorius, leading away from the body imprint, which demonstrates that the animal was alive at the time its body imprinted the sediment.
Gwyneddichnium is an ichnogenus from the Late Triassic of North America and Europe. It represents a form of reptile footprints and trackways, likely produced by small tanystropheids such as Tanytrachelos. Gwyneddichnium includes a single species, Gwyneddichnium major. Two other proposed species, G. elongatum and G. minore, are indistinguishable from G. major apart from their smaller size and minor taphonomic discrepancies. As a result, they are considered junior synonyms of G. major.
