A mortichnia is the "death march", or last walk, of a living creature.
These are sometimes preserved as
fossil footprints
A fossil track or ichnite (Ancient Greek, Greek "''ιχνιον''" (''ichnion'') – a track, trace or footstep) is a fossilized footprint. This is a type of trace fossil. A fossil trackway is a sequence of fossil tracks left by a single organism ...
.
Notable examples
In 2002 the mortichnia of a
horseshoe crab
Horseshoe crabs are marine and brackish water arthropods of the family Limulidae and the only living members of the order Xiphosura. Despite their name, they are not true crabs or crustaceans: they are chelicerates, most closely related to arachn ...
was found in
lithographic limestone
Lithographic limestone is hard limestone that is sufficiently fine-grained, homogeneous and defect free to be used for lithography.
Geologists use the term "lithographic texture" to refer to a grain size under 1/250 mm.
The term "sublithog ...
in
Bavaria
Bavaria ( ; ), officially the Free State of Bavaria (german: Freistaat Bayern, link=no ), is a state in the south-east of Germany. With an area of , Bavaria is the largest German state by land area, comprising roughly a fifth of the total lan ...
,
Germany
Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwe ...
.
The trail measured 9.7m and was left about 150 million years ago when the crab died in an
anoxic
The term anoxia means a total depletion in the level of oxygen, an extreme form of hypoxia or "low oxygen". The terms anoxia and hypoxia are used in various contexts:
* Anoxic waters, sea water, fresh water or groundwater that are depleted of diss ...
lagoon
A lagoon is a shallow body of water separated from a larger body of water by a narrow landform, such as reefs, barrier islands, barrier peninsulas, or isthmuses. Lagoons are commonly divided into ''coastal lagoons'' (or ''barrier lagoons'') a ...
.
The footprints left enough evidence for researchers to determine that the creature probably fell into the lagoon upside-down, righted itself, and started walking before succumbing to the
anoxic conditions of the water.
The trackway is currently exhibited at the
Wyoming Dinosaur Center
The Wyoming Dinosaur Center is located in Thermopolis, Wyoming and is one of the few dinosaur museums in the world to have excavation sites within driving distance. The museum displays the Thermopolis Specimen of '' Archaeopteryx'', which is the o ...
.
See also
* ''
Kouphichnium
''Kouphichnium'' is an ichnogenus that has been attributed to limulids (horseshoe crabs). ''Kouphichnium'' fossils resemble the footprints of birds, sometimes in conjunction with a medial line, and were initially thought to be bird or pterosaur ...
'', an
ichnogenus
An ichnotaxon (plural ichnotaxa) is "a taxon based on the fossilized work of an organism", i.e. the non-human equivalent of an artifact. ''Ichnotaxa'' comes from the Greek ίχνος, ''ichnos'' meaning ''track'' and ταξις, ''taxis'' meaning ...
attributed to horseshoe crabs
References
Walking
Anoxic waters
Trace fossils
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