Ichnite

An ichnite (Greek "ιχνιον" (ichnion) – a track, trace or footstep) is a fossilised footprint. This is a type of trace fossil. Over the years, many ichnites have been found, around the world, giving important clues about the behaviour (and foot structure and stride) of the animals that made them. For instance, multiple ichnites of a single species, close together, suggest 'herd' or 'pack' behaviour of that species.

Combinations of footprints of different species provide clues about the interactions of those species. Even a set of footprints of a single animal gives important clues, as to whether it was bipedal or quadrupedal. In this way, it has been suggested that some pterosaurs, when on the ground, used their forelimbs in an unexpected quadrupedal action.

Special conditions are required, in order to preserve a footprint made in soft ground (such as an alluvial plain or a formative sedimentary deposit). A possible scenario is a sea or lake shore that became dried out to a firm mud in hot, dry conditions, received the footprints (because it would only have been partially hardened and the animal would have been heavy) and then became silted over in a flash storm.

The first ichnite found was in 1800 in Massachusetts, USA, by a farmer named Pliny Moody, who found 1-foot (31 cm) long fossilized footprints. They were thought by Harvard and Yale scholars to be from "Noah's Raven." [1]

A famous group of ichnites was found in a limestone quarry at Ardley, 20 km Northeast of Oxford, England, in 1997. They were thought to have been made by Megalosaurus and possibly Cetiosaurus. There are replicas of some of these footprints, set across the lawn of Oxford University Museum of Natural History (OUMNH).

A creature named Cheirotherium was, for a long time and still may be, only known from its fossilised trail. Its footprints were first found in 1834, in Thuringia, Germany, dating from the Late Triassic Period.

The largest known dinosaur footprints, belonging to sauropods and dating from the early Cretaceous were found to the north of Broome on the Dampier Peninsula, Western Australia, with some footprints measuring 1.7m.[2][3]

JialingpusYuechiensis(Ichnite)-PaleozoologicalMuseumOfChina-May23-08
A reverse ichnite of the impression of Jialingpus yuechiensis, on display at the Paleozoological Museum of China.

Gallery of images

Cheirotherium prints possibly Ticinosuchus

Cheirotherium trace fossil, displayed in Oxford University Museum of Natural History.

MammothFootImpressions25

Cross-section of Pleistocene mammoth footprints at The Mammoth Site, Hot Springs, South Dakota.

Eubrontes01

Eubrontes, a dinosaur footprint in the Lower Jurassic Moenave Formation at the St. George Dinosaur Discovery Site at Johnson Farm, southwestern Utah.

Gigandipus

Gigandipus, a dinosaur footprint in the Lower Jurassic Moenave Formation at the St. George Dinosaur Discovery Site at Johnson Farm, southwestern Utah.

CamelFootprintBarstowMiocene

Cameloid footprint (Lamaichnum alfi Sarjeant and Reynolds, 1999; convex hyporelief) from the Barstow Formation (Miocene) of Rainbow Basin, California.

Saurichnites intermedius

Saurichnites intermedius

See also

References

  1. ^ "Noahs Raven".
  2. ^ Devlin, Hannah; agencies (2017-03-28). "World's largest dinosaur footprints discovered in Western Australia". The Guardian. ISSN 0261-3077. Retrieved 2017-12-01.
  3. ^ Salisbury, Steven W.; Romilio, Anthony; Herne, Matthew C.; Tucker, Ryan T.; Nair, Jay P. (2016-12-12). "The Dinosaurian Ichnofauna of the Lower Cretaceous (Valanginian–Barremian) Broome Sandstone of the Walmadany Area (James Price Point), Dampier Peninsula, Western Australia". Journal of Vertebrate Paleontology. 36 (sup1): 1–152. doi:10.1080/02724634.2016.1269539. ISSN 0272-4634.

External links

Chirotherium

Chirotherium, also known as Cheirotherium (‘hand-beast’), is a Triassic trace fossil consisting of five-fingered (pentadactyle) footprints and whole tracks. These look, by coincidence, remarkably like the hands of apes and bears, with the outermost toe having evolved to extend out to the side like a thumb, although probably only functioning to provide a firmer grip in mud. Chirotherium tracks were first found in 1834 in Lower Triassic sandstone (Buntsandstein) in Thuringia, Germany, dating from about 243 million years ago (mya).

The creatures who made the footprints and tracks were probably pseudosuchian archosaurs related to the ancestors of the crocodiles. They likely belonged to either prestosuchidae or rauisuchidae groups, which were both large carnivores with semi-erect gaits.

Jurassic Museum of Asturias

The Jurassic Museum of Asturias (Spanish: Museo del Jurásico de Asturias; MUJA) is located in the area of Rasa de San Telmo near the parish (administrative division) of Llastres in the municipality of Colunga, Asturias, Spain. Though the municipality of Ribadesella was initially proposed, Colunga was chosen for the building site in the late 1990s. Several landmarks are visible from the museum including the Bay of Biscay, the Sierra del Sueve, and the Picos de Europa. Strategically located over a mount on the Rasa de San Temo, the museum is in the midst the Jurassic Asturias.The museum displays and collections cover 3,500 million years, and although they emphasize the three stages of the Mesozoic (Triassic, Jurassic and Cretaceous), information is also presented on the preceding and subsequent periods. Different stages of the Jurassic geologic period and system are on display. Corridors contain over 20 dinosaur replicas; measuring over 12 metres (39 ft) in height, their weight would exceed ten tons if the replicas were real. A rich collection of footprints and fossils found in the Asturian Jurassic coastline from ten paleontological sites are exhibited in the exposition halls and are said to be "the most complete informative and representative collection of dinosaur remains in the world."Founded March 31, 2004 and representing an investment of 12 million euros, MUJA belongs to the Asturian network of public museums. The museum's goal is to illustrate the factors involved in the composition of life on Earth. The palaeontologist José Carlos García-Ramos from the University of Oviedo leads the museum's scientific team.

Trace fossil

A trace fossil, also ichnofossil ( ; from Greek: ἴχνος ikhnos "trace, track"), is a geological record of biological activity. Ichnology is the study of such traces, and is the work of ichnologists. Trace fossils may consist of impressions made on or in the substrate by an organism: for example, burrows, borings (bioerosion), urolites (erosion caused by evacuation of liquid wastes), footprints and feeding marks, and root cavities. The term in its broadest sense also includes the remains of other organic material produced by an organism—for example coprolites (fossilized droppings) or chemical markers—or sedimentological structures produced by biological means—for example, stromatolites. Trace fossils contrast with body fossils, which are the fossilized remains of parts of organisms' bodies, usually altered by later chemical activity or mineralization.

Sedimentary structures, for example those produced by empty shells rolling along the sea floor, are not produced through the behaviour of an organism and not considered trace fossils.

The study of traces - ichnology - divides into paleoichnology, or the study of trace fossils, and neoichnology, the study of modern traces. Ichnological science offers many challenges, as most traces reflect the behaviour—not the biological affinity—of their makers. Accordingly, researchers classify trace fossils into form genera, based on their appearance and on the implied behaviour, or ethology, of their makers.

Winton Formation

The Winton Formation is a Cretaceous formation in central-western Queensland, Australia. It is late Albian to early Turonian in age.The formation is a rock unit that blankets large areas of central-western Queensland. It consists of sedimentary rocks such as sandstone, siltstone and claystone. The sediments that make up these rocks represent the remnants of the river plains that filled the basin left by the Eromanga Sea - an inland sea that covered large parts of Queensland and central Australia at least four times during the Early Cretaceous. Great meandering rivers, forest pools and swamps, creeks, lakes and coastal estuaries all left behind different types of sediment.

In some areas, the Winton Formation is over 400 metres thick. To bring with them such a huge amount of sediment, the rivers that flowed across these plains must have been comparable in size to the present-day Amazon or Mississippi rivers. As more and more sediment was brought in, the margins of the inland sea slowly contracted. By around 95 million years ago, the deposition was complete and the inland sea would never be seen again.

By virtue of its age and the environmental conditions under which the rocks it consists of were deposited, the Winton Formation represents one of the richest sources of dinosaur fossils anywhere in Australia.

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