Ichnite
Encyclopedia
Ancient Greek
Ancient Greek is the stage of the Greek language in the periods spanning the times c. 9th–6th centuries BC, , c. 5th–4th centuries BC , and the c. 3rd century BC – 6th century AD of ancient Greece and the ancient world; being predated in the 2nd millennium BC by Mycenaean Greek...
"ιχνιον" (ichnion) – a track, trace or footstep) is a fossilised footprint. This is a type of trace fossil
Trace fossil
Trace fossils, also called ichnofossils , are geological records of biological activity. Trace fossils may be impressions made on the substrate by an organism: for example, burrows, borings , urolites , footprints and feeding marks, and root cavities...
. 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 biped
Biped
Bipedalism is a form of terrestrial locomotion where an organism moves by means of its two rear limbs, or legs. An animal or machine that usually moves in a bipedal manner is known as a biped , meaning "two feet"...
al or quadruped
Quadruped
Quadrupedalism is a form of land animal locomotion using four limbs or legs. An animal or machine that usually moves in a quadrupedal manner is known as a quadruped, meaning "four feet"...
al. In this way, it has been suggested that some pterosaur
Pterosaur
Pterosaurs were flying reptiles of the clade or order Pterosauria. They existed from the late Triassic to the end of the Cretaceous Period . Pterosaurs are the earliest vertebrates known to have evolved powered flight...
s, 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
Alluvial plain
An alluvial plain is a relatively flat landform created by the deposition of sediment over a long period of time by one or more rivers coming from highland regions, from which alluvial soil forms...
or a formative sedimentary
Sedimentary rock
Sedimentary rock are types of rock that are formed by the deposition of material at the Earth's surface and within bodies of water. Sedimentation is the collective name for processes that cause mineral and/or organic particles to settle and accumulate or minerals to precipitate from a solution....
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."
A famous group of ichnites was found in a limestone quarry at Ardley
Ardley
Ardley is a village in Ardley with Fewcott civil parish in Oxfordshire, England, about northwest of Bicester. The parish includes the village of Fewcott that is now contiguous with Ardley.-History:...
, 20 km Northeast of Oxford
Oxford
The city of Oxford is the county town of Oxfordshire, England. The city, made prominent by its medieval university, has a population of just under 165,000, with 153,900 living within the district boundary. It lies about 50 miles north-west of London. The rivers Cherwell and Thames run through...
, England
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
, in 1997. They were thought to have been made by Megalosaurus
Megalosaurus
Megalosaurus is a genus of large meat-eating theropod dinosaurs of the Middle Jurassic period of Europe...
and possibly Cetiosaurus
Cetiosaurus
Cetiosaurus meaning 'whale lizard', from the Greek cetus/κητος meaning 'sea monster' and saurus/σαυρος meaning 'lizard', was a sauropod dinosaur from the Mid to Late Jurassic Period in what are now Europe and Africa. It is estimated to have been about long and to have weighed roughly...
. There are replicas of some of these footprints, set across the lawn of Oxford University Museum of Natural History
Oxford University Museum of Natural History
The Oxford University Museum of Natural History, sometimes known simply as the Oxford University Museum, is a museum displaying many of the University of Oxford's natural history specimens, located on Parks Road in Oxford, England. It also contains a lecture theatre which is used by the...
(OUMNH).
A creature named Cheirotherium
Chirotherium
Chirotherium, also known as Cheirotherium , is the name of a Triassic archosaur known only from fossil imprints of its tracks...
was, for a long time and still may be, only known from its fossilised trail. Its footprints were first found in 1834, in Thuringia
Thuringia
The Free State of Thuringia is a state of Germany, located in the central part of the country.It has an area of and 2.29 million inhabitants, making it the sixth smallest by area and the fifth smallest by population of Germany's sixteen states....
, Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
, dating from the Late Triassic
Triassic
The Triassic is a geologic period and system that extends from about 250 to 200 Mya . As the first period of the Mesozoic Era, the Triassic follows the Permian and is followed by the Jurassic. Both the start and end of the Triassic are marked by major extinction events...
Period.