The Early Triassic is the first of three
epoch
In chronology and periodization, an epoch or reference epoch is an instant in time chosen as the origin of a particular calendar era. The "epoch" serves as a reference point from which time is measured.
The moment of epoch is usually decided b ...
s of the
Triassic
The Triassic ( ; sometimes symbolized đ) is a geologic period and system which spans 50.5 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.4 Mya. The Triassic is t ...
Period of the
geologic timescale
The geologic time scale or geological time scale (GTS) is a representation of time based on the rock record of Earth. It is a system of chronological dating that uses chronostratigraphy (the process of relating strata to time) and geochron ...
. It spans the time between 251.9
Ma and Ma (million years ago). Rocks from this epoch are collectively known as the Lower Triassic
Series
Series may refer to:
People with the name
* Caroline Series (born 1951), English mathematician, daughter of George Series
* George Series (1920â1995), English physicist
Arts, entertainment, and media
Music
* Series, the ordered sets used i ...
, which is a unit in
chronostratigraphy
Chronostratigraphy is the branch of stratigraphy that studies the ages of rock strata in relation to time.
The ultimate aim of chronostratigraphy is to arrange the sequence of deposition and the time of deposition of all rocks within a geological ...
. The Early Triassic is the oldest epoch of the
Mesozoic
The Mesozoic Era is the Era (geology), era of Earth's Geologic time scale, geological history, lasting from about , comprising the Triassic, Jurassic and Cretaceous Period (geology), Periods. It is characterized by the dominance of archosaurian r ...
Era
An era is a span of time.
Era or ERA may also refer to:
* Era (geology), a subdivision of geologic time
* Calendar era
Education
* Academy of European Law (German: '), an international law school
* ERA School, in Melbourne, Australia
* E ...
. It is preceded by the
Lopingian
The Lopingian is the uppermost series/last epoch of the Permian. It is the last epoch of the Paleozoic. The Lopingian was preceded by the Guadalupian and followed by the Early Triassic.
The Lopingian is often synonymous with the informal te ...
Epoch (late
Permian
The Permian ( ) is a geologic period and System (stratigraphy), stratigraphic system which spans 47 million years, from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.902 Mya. It is the s ...
,
Paleozoic
The Paleozoic ( , , ; or Palaeozoic) Era is the first of three Era (geology), geological eras of the Phanerozoic Eon. Beginning 538.8 million years ago (Ma), it succeeds the Neoproterozoic (the last era of the Proterozoic Eon) and ends 251.9 Ma a ...
Era
An era is a span of time.
Era or ERA may also refer to:
* Era (geology), a subdivision of geologic time
* Calendar era
Education
* Academy of European Law (German: '), an international law school
* ERA School, in Melbourne, Australia
* E ...
) and followed by the
Middle Triassic
In the geologic timescale, the Middle Triassic is the second of three epoch (geology), epochs of the Triassic period (geology), period or the middle of three series (stratigraphy), series in which the Triassic system (stratigraphy), system is di ...
Epoch. The Early Triassic is divided into the
Induan
The Induan is the first age of the Early Triassic epoch in the geologic timescale, or the lowest stage of the Lower Triassic series in chronostratigraphy. It spans the time between 251.9 Ma and 249.9 Ma (million years ago). The Induan is so ...
and
Olenekian
In the geologic timescale, the Olenekian is an age (geology), age in the Early Triassic epoch (geology), epoch; in chronostratigraphy, it is a stage (stratigraphy), stage in the Lower Triassic series (stratigraphy), series. It spans the time betw ...
age
Age or AGE may refer to:
Time and its effects
* Age, the amount of time someone has been alive or something has existed
** East Asian age reckoning, an Asian system of marking age starting at 1
* Ageing or aging, the process of becoming older
...
s. The Induan is subdivided into the
Griesbachian
The Induan is the first age of the Early Triassic epoch in the geologic timescale, or the lowest stage of the Lower Triassic series in chronostratigraphy. It spans the time between 251.9 Ma and 249.9 Ma (million years ago). The Induan is someti ...
and
Dienerian subages and the Olenekian is subdivided into the
Smithian and
Spathian subages.
The Lower Triassic series is coeval with the Scythian Stage, which is today not included in the official timescales but can be found in older literature. In Europe, most of the Lower Triassic is composed of
Buntsandstein
The Buntsandstein (German for ''coloured'' or ''colourful sandstone'') or Bunter sandstone is a lithostratigraphy, lithostratigraphic and allostratigraphy, allostratigraphic unit (a sequence of rock strata) in the Subsurface (geology), subsurface ...
, a
lithostratigraphic
Lithostratigraphy is a sub-discipline of stratigraphy, the geological science associated with the study of strata or rock layers. Major focuses include geochronology, comparative geology, and petrology.
In general, strata are primarily igneous ...
unit of continental
red beds
Red beds (or redbeds) are sedimentary rocks, typically consisting of sandstone, siltstone, and shale, that are predominantly red in color due to the presence of ferric oxides. Frequently, these red-colored sedimentary strata locally contain t ...
.
The Early Triassic and partly also the
Middle Triassic
In the geologic timescale, the Middle Triassic is the second of three epoch (geology), epochs of the Triassic period (geology), period or the middle of three series (stratigraphy), series in which the Triassic system (stratigraphy), system is di ...
span the interval of biotic recovery from the
Permian-Triassic extinction event, the most severe
mass extinction
An extinction event (also known as a mass extinction or biotic crisis) is a widespread and rapid decrease in the biodiversity on Earth. Such an event is identified by a sharp fall in the diversity and abundance of multicellular organisms. It occ ...
event in Earth's history.
A second extinction event, the
Smithian-Spathian boundary event, occurred during the Olenekian. A third extinction event occurred at the Olenekian-Anisian boundary, marking the end of the Early Triassic epoch.
Early Triassic climate
The climate during the Early Triassic Epoch (especially in the interior of the supercontinent
Pangaea
Pangaea or Pangea ( ) was a supercontinent that existed during the late Paleozoic and early Mesozoic eras. It assembled from the earlier continental units of Gondwana, Euramerica and Siberia during the Carboniferous period approximately 335 mi ...
) was generally arid, rainless and dry and deserts were widespread; however the poles possessed a
temperate climate
In geography, the temperate climates of Earth occur in the middle latitudes (approximately 23.5° to 66.5° N/S of the Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ra ...
. The pole-to-equator
temperature gradient
A temperature gradient is a physical quantity that describes in which direction and at what rate the temperature changes the most rapidly around a particular location. The temperature spatial gradient is a vector quantity with Dimensional analysis, ...
was temporally flat during the Early Triassic and may have allowed tropical species to extend their distribution poleward. This is evidenced by the global distribution of
ammonoids
Ammonoids are extinct, (typically) coiled-shelled cephalopods comprising the subclass Ammonoidea. They are more closely related to living octopuses, squid, and cuttlefish (which comprise the clade Coleoidea) than they are to nautiluses (family N ...
.
The extremely hot ocean temperatures facilitated extremely powerful hurricanes that frequently hit the coast of North China.
The mostly hot climate of the Early Triassic may have been caused by late volcanic eruptions of the
Siberian Traps
The Siberian Traps () are a large region of volcanic rock, known as a large igneous province, in Siberia, Russia. The massive eruptive event that formed the trap rock, traps is one of the largest known Volcano, volcanic events in the last years ...
,
which had probably triggered the
Permian-Triassic extinction event and accelerated the rate of
global warming
Present-day climate change includes both global warmingâthe ongoing increase in global average temperatureâand its wider effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes ...
into the Triassic.
Studies suggest that Early Triassic climate was very volatile, punctuated by a number of relatively rapid global temperature changes, marine anoxic events, and
carbon cycle
The carbon cycle is a part of the biogeochemical cycle where carbon is exchanged among the biosphere, pedosphere, geosphere, hydrosphere, and atmosphere of Earth. Other major biogeochemical cycles include the nitrogen cycle and the water cycl ...
disturbances,
which led to subsequent extinction events in the aftermath of the
Permian-Triassic extinction event.
On the other hand, an alternative hypothesis proposes these Early Triassic climatic perturbations and biotic upheavals that inhibited the recovery of life following the P-T mass extinction to have been linked to forcing driven by changes in the Earth's obliquity defined by a roughly 32.8 thousand year periodicity with strong 1.2 million year modulations. According to proponents of this hypothesis, radiometric dating indicates that major activity from the Siberian Traps ended very shortly after the end-Permian extinction and did not span the entire Early Triassic epoch, thus not being the primary culprit for the climatic changes throughout this epoch.
Early Triassic life
Fauna and flora

The Triassic Period opened in the aftermath of the
PermianâTriassic extinction event
The PermianâTriassic extinction event (also known as the PâT extinction event, the Late Permian extinction event, the Latest Permian extinction event, the End-Permian extinction event, and colloquially as the Great Dying,) was an extinction ...
. The massive extinctions that ended the
Permian
The Permian ( ) is a geologic period and System (stratigraphy), stratigraphic system which spans 47 million years, from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.902 Mya. It is the s ...
Period (and with that the
Paleozoic
The Paleozoic ( , , ; or Palaeozoic) Era is the first of three Era (geology), geological eras of the Phanerozoic Eon. Beginning 538.8 million years ago (Ma), it succeeds the Neoproterozoic (the last era of the Proterozoic Eon) and ends 251.9 Ma a ...
Era
An era is a span of time.
Era or ERA may also refer to:
* Era (geology), a subdivision of geologic time
* Calendar era
Education
* Academy of European Law (German: '), an international law school
* ERA School, in Melbourne, Australia
* E ...
) caused extreme hardships for the surviving species.
The Early Triassic Epoch saw the biotic recovery of life after the biggest mass extinction event of the past, which took millions of years due to the severity of the event and the harsh Early Triassic climate. Many types of
coral
Corals are colonial marine invertebrates within the subphylum Anthozoa of the phylum Cnidaria. They typically form compact Colony (biology), colonies of many identical individual polyp (zoology), polyps. Coral species include the important Coral ...
s,
brachiopod
Brachiopods (), phylum (biology), phylum Brachiopoda, are a phylum of animals that have hard "valves" (shells) on the upper and lower surfaces, unlike the left and right arrangement in bivalve molluscs. Brachiopod valves are hinged at the rear e ...
s,
molluscs
Mollusca is a phylum of protostome, protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant taxon, extant species of molluscs are recognized, making it the second-largest animal phylum ...
,
echinoderm
An echinoderm () is any animal of the phylum Echinodermata (), which includes starfish, brittle stars, sea urchins, sand dollars and sea cucumbers, as well as the sessile sea lilies or "stone lilies". While bilaterally symmetrical as ...
s, and other
invertebrate
Invertebrates are animals that neither develop nor retain a vertebral column (commonly known as a ''spine'' or ''backbone''), which evolved from the notochord. It is a paraphyletic grouping including all animals excluding the chordata, chordate s ...
s had disappeared. The Permian vegetation, which was dominated by ''
Glossopteris'' in the Southern Hemisphere, ceased to exist.
Other groups, such as
Actinopterygii
Actinopterygii (; ), members of which are known as ray-finned fish or actinopterygians, is a class (biology), class of Osteichthyes, bony fish that comprise over 50% of living vertebrate species. They are so called because of their lightly built ...
, appear to have been less affected by this extinction event and body size was not a selective factor during the extinction event.
Animals that were most successful in the Early Triassic were those with high metabolisms.
Different patterns of recovery are evident on land and in the sea. Early Triassic faunas lacked biodiversity and were relatively homogeneous due to the effects of the extinction. The ecological recovery on land took 30 million years, well into the
Late Triassic
The Late Triassic is the third and final epoch (geology), epoch of the Triassic geologic time scale, Period in the geologic time scale, spanning the time between annum, Ma and Ma (million years ago). It is preceded by the Middle Triassic Epoch a ...
.
Two Early Triassic
lagerstätten stand out due to their exceptionally high
biodiversity
Biodiversity is the variability of life, life on Earth. It can be measured on various levels. There is for example genetic variability, species diversity, ecosystem diversity and Phylogenetics, phylogenetic diversity. Diversity is not distribut ...
, the
Dienerian aged
Guiyang biota and the earliest
Spathian aged
Paris biota.
Terrestrial biota
The most common land vertebrate was the small
herbivorous
A herbivore is an animal anatomically and physiologically evolved to feed on plants, especially upon vascular tissues such as foliage, fruits or seeds, as the main component of its diet. These more broadly also encompass animals that eat n ...
synapsid
Synapsida is a diverse group of tetrapod vertebrates that includes all mammals and their extinct relatives. It is one of the two major clades of the group Amniota, the other being the more diverse group Sauropsida (which includes all extant rept ...
''
Lystrosaurus
''Lystrosaurus'' (; 'shovel lizard'; proper Ancient Greek is ''lĂstron'' âtool for leveling or smoothing, shovel, spade, hoeâ) is an extinct genus of herbivorous dicynodont therapsids from the late Permian and Early Triassic epochs (arou ...
''. Often interpreted as a
disaster taxon (although this view was questioned), ''Lystrosaurus'' had a wide range across Pangea. In the southern part of the supercontinent, it co-occurred with the non-mammalian
cynodont
Cynodontia () is a clade of eutheriodont therapsids that first appeared in the Late Permian (approximately 260 Megaannum, mya), and extensively diversified after the PermianâTriassic extinction event. Mammals are cynodonts, as are their extin ...
s ''
Galesaurus
''Galesaurus'' (from the Greek roots for 'weasel' and 'lizard') is an extinct genus of carnivorous cynodont therapsid that lived between the Induan and the Olenekian stages of the Early Triassic in what is now South Africa. It was incorrectly cl ...
'' and ''
Thrinaxodon
''Thrinaxodon'' is an extinct genus of cynodonts which lived in what are now South Africa and Antarctica during the Late Permian - Early Triassic. ''Thrinaxodon'' lived just before, during, and right after the PermianâTriassic mass extinction ...
'', early relatives of
mammal
A mammal () is a vertebrate animal of the Class (biology), class Mammalia (). Mammals are characterised by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three ...
s. The first
archosauriforms appeared, such as ''
Erythrosuchus
''Erythrosuchus'' (from , 'red' and , 'crocodile') is an extinct genus of archosauriform reptiles from the early Triassic of South Africa. Remains have been found from the Cynognathus Assemblage Zone of the Beaufort Group in the Karoo of South ...
'' (
Olenekian
In the geologic timescale, the Olenekian is an age (geology), age in the Early Triassic epoch (geology), epoch; in chronostratigraphy, it is a stage (stratigraphy), stage in the Lower Triassic series (stratigraphy), series. It spans the time betw ...
-
Ladinian
The Ladinian is a stage and age in the Middle Triassic series or epoch. It spans the time between Ma and ~237 Ma (million years ago). The Ladinian was preceded by the Anisian and succeeded by the Carnian (part of the Upper or Late Triassic ...
). This group includes the ancestors of
crocodile
Crocodiles (family (biology), family Crocodylidae) or true crocodiles are large, semiaquatic reptiles that live throughout the tropics in Africa, Asia, the Americas and Australia. The term "crocodile" is sometimes used more loosely to include ...
s and
dinosaurs
Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic Geological period, period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the #Evolutio ...
(including
birds
Birds are a group of warm-blooded vertebrates constituting the class (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard-shelled eggs, a high Metabolism, metabolic rate, a fou ...
). Fossilized
foot prints of
dinosauromorphs are known from the Olenekian. The Early Triassic entomofauna is very poorly understood because of the paucity of insect fossils from this epoch.
The
flora
Flora (: floras or florae) is all the plant life present in a particular region or time, generally the naturally occurring (indigenous (ecology), indigenous) native plant, native plants. The corresponding term for animals is ''fauna'', and for f ...
was
gymnosperm
The gymnosperms ( ; ) are a group of woody, perennial Seed plant, seed-producing plants, typically lacking the protective outer covering which surrounds the seeds in flowering plants, that include Pinophyta, conifers, cycads, Ginkgo, and gnetoph ...
-dominated at the onset of the Triassic, but changed rapidly and became
lycopod-dominated (e.g. ''
Pleuromeia
''Pleuromeia'' is an extinct genus of lycophytes related to modern quillworts (''Isoetes''). ''Pleuromeia'' dominated vegetation during the Early Triassic all over Eurasia and elsewhere, in the aftermath of the PermianâTriassic extinction eve ...
'') during the Griesbachian-Dienerian
ecological crisis
An ecological or environmental crisis occurs when changes to the environment of a species or population destabilizes its continued survival. Some of the important causes include:
* Degradation of an abiotic ecological factor (for example, incr ...
. This change coincided with the extinction of the Permian ''
Glossopteris'' flora.
In the
Spathian subage, the flora changed back to gymnosperm and
pteridophyte
A pteridophyte is a vascular plant (with xylem and phloem) that reproduces by means of spores. Because pteridophytes produce neither flowers nor seeds, they are sometimes referred to as " cryptogams", meaning that their means of reproduction is ...
dominated. These shifts reflect global changes in
precipitation
In meteorology, precipitation is any product of the condensation of atmospheric water vapor that falls from clouds due to gravitational pull. The main forms of precipitation include drizzle, rain, rain and snow mixed ("sleet" in Commonwe ...
and temperature.
Floral diversity was overall very low during the Early Triassic, as plant life had yet to fully recover from the Permian-Triassic extinction.
Microbially induced sedimentary structures (MISS) are common in the fossil record of North China in the immediate aftermath of the Permian-Triassic extinction, indicating that
microbial mats
A microbial mat is a multi-layered sheet or biofilm of microbial colony (biology), colonies, composed of mainly bacteria and/or archaea. Microbial mats grow at interface (chemistry), interfaces between different types of material, mostly on submer ...
dominated local terrestrial ecosystems following the Permian-Triassic boundary. The regional prevalence of MISS is attributable to a decrease in bioturbation and grazing pressure as a result of aridification and temperature increase.
MISS have also been reported from Early Triassic fossil deposits in Arctic Canada. The disappearance of MISS later in the Early Triassic has been interpreted as a signal of increased bioturbation and recovery of terrestrial ecosystems.
Aquatic biota
In the oceans, the most common Early Triassic hard-shelled marine invertebrates were
bivalves
Bivalvia () or bivalves, in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of aquatic molluscs (marine and freshwater) that have laterally compressed soft bodies enclosed by a calcified exoskeleton consis ...
,
gastropods
Gastropods (), commonly known as slugs and snails, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda ().
This class comprises snails and slugs from saltwater, freshwater, and from the land. Ther ...
,
ammonoids,
echinoids
Sea urchins or urchins () are echinoderms in the class (biology), class Echinoidea. About 950 species live on the seabed, inhabiting all oceans and depth zones from the intertidal zone to deep seas of . They typically have a globular body cove ...
, and a few articulate
brachiopod
Brachiopods (), phylum (biology), phylum Brachiopoda, are a phylum of animals that have hard "valves" (shells) on the upper and lower surfaces, unlike the left and right arrangement in bivalve molluscs. Brachiopod valves are hinged at the rear e ...
s.
Conodonts
Conodonts, are an extinct group of marine jawless vertebrates belonging to the Class (biology), class Conodonta (from Ancient Greek ÎşáżśÎ˝ÎżĎ (''kĹnos''), meaning "cone", and á˝Î´ÎżĎĎ (''odoĂşs''), meaning "tooth"). They are primarily known ...
experienced a revival in diversity following a
nadir
The nadir is the direction pointing directly ''below'' a particular location; that is, it is one of two vertical directions at a specified location, orthogonal to a horizontal flat surface.
The direction opposite of the nadir is the zenith.
Et ...
during the Permian.
The first
oyster
Oyster is the common name for a number of different families of salt-water bivalve molluscs that live in marine or brackish habitats. In some species, the valves are highly calcified, and many are somewhat irregular in shape. Many, but no ...
s (''
Liostrea'') appeared in the Early Triassic. They grew on the shells of living ammonoids as epizoans.
Microbial reefs were common, possibly due to lack of competition with
metazoan
Animals are multicellular, eukaryotic organisms in the biological kingdom Animalia (). With few exceptions, animals consume organic material, breathe oxygen, have myocytes and are able to move, can reproduce sexually, and grow from a ho ...
reef builders as a result of the extinction. However, transient metazoan
reef
A reef is a ridge or shoal of rock, coral, or similar relatively stable material lying beneath the surface of a natural body of water. Many reefs result from natural, abiotic component, abiotic (non-living) processes such as deposition (geol ...
s reoccurred during the Olenekian wherever permitted by environmental conditions.
Ammonoids
Ammonoids are extinct, (typically) coiled-shelled cephalopods comprising the subclass Ammonoidea. They are more closely related to living octopuses, squid, and cuttlefish (which comprise the clade Coleoidea) than they are to nautiluses (family N ...
show blooms followed by extinctions during the Early Triassic.
Aquatic vertebrates diversified after the extinction:
* Fishes: Many species of fish had a
worldwide distribution during the Early Triassic.
Typical Triassic
ray-finned fishes, such as ''
Australosomus'', ''
Birgeria'', ''
Bobasatrania
''Bobasatrania'' is an extinct genus of prehistoric marine Actinopterygii, ray-finned fish that survived the Permian-Triassic extinction event. Fossils of ''Bobasatrania'' were found in beds of Changhsingian (Lopingian, late Permian) to Ladinian ...
'', ''
Boreosomus'', ''
Pteronisculus'',
Parasemionotidae and ''
Saurichthys
''Saurichthys'' (from , 'lizard' and 'fish') is an extinct genus of predatory Actinopterygii, ray-finned fish from the Triassic period (geology), Period. It is the type genus of the family (taxonomy), family Saurichthyidae (Changhsingian-Ju ...
'' appeared close to the Permian-Triassic boundary, whereas
neopterygians (including
stem
Stem or STEM most commonly refers to:
* Plant stem, a structural axis of a vascular plant
* Stem group
* Science, technology, engineering, and mathematics
Stem or STEM can also refer to:
Language and writing
* Word stem, part of a word respon ...
teleosts) diversified later during the Triassic, though the pattern of the Triassic diversification of
bony fishes
Osteichthyes ( ; ), also known as osteichthyans or commonly referred to as the bony fish, is a diverse clade of vertebrate animals that have endoskeletons primarily composed of bone tissue. They can be contrasted with the Chondrichthyes (cartila ...
is not well understood due to a
taphonomic megabias (Spathian-Bithynian Gap, SBG) in the late Early Triassic and early Middle Triassic. The earliest large durophagous neopterygian is known from this gap, suggesting an early onset in feeding specializations of this group. Most bony fish reached large body sizes during the Early Triassic.
Coelacanth
Coelacanths ( ) are an ancient group of lobe-finned fish (Sarcopterygii) in the class Actinistia. As sarcopterygians, they are more closely related to lungfish and tetrapods (the terrestrial vertebrates including living amphibians, reptiles, bi ...
s show a peak in their diversity during this epoch, including new modes of life, such as the fork-tailed ''
Rebellatrix''.
Chondrichthyes
Chondrichthyes (; ) is a class of jawed fish that contains the cartilaginous fish or chondrichthyans, which all have skeletons primarily composed of cartilage. They can be contrasted with the Osteichthyes or ''bony fish'', which have skeleto ...
are represented by
Hybodontiformes like ''
Palaeobates'', ''
Omanoselache'', ''
Lissodus'', some
Neoselachii
Elasmobranchii () is a subclass of Chondrichthyes or cartilaginous fish, including modern sharks ( division Selachii), and batomorphs (division Batomorphi, including rays, skates, and sawfish). Members of this subclass are characterised by h ...
, as well as a few last survivors of the
Eugeneodontida (''
Caseodus'', ''
Fadenia
''Fadenia'' is an extinct genus of eugeneodontid holocephalian chondrichthyan from the Carboniferous Period of Missouri (United States), the Permian period of Greenland, and the Early Triassic epoch of British Columbia, Canada ( Sulphur Mount ...
'').
*
Amphibian
Amphibians are ectothermic, anamniote, anamniotic, tetrapod, four-limbed vertebrate animals that constitute the class (biology), class Amphibia. In its broadest sense, it is a paraphyletic group encompassing all Tetrapod, tetrapods, but excl ...
s: Relatively large, marine
temnospondyl
Temnospondyli (from Greek language, Greek ĎÎΟνξΚν, ''temnein'' 'to cut' and ĎĎĎνδĎ
ΝοĎ, ''spondylos'' 'vertebra') or temnospondyls is a diverse ancient order (biology), order of small to giant tetrapodsâoften considered Labyrinth ...
amphibians, such as ''
Aphaneramma'' or ''
Wantzosaurus'', were geographically widespread during the
Induan
The Induan is the first age of the Early Triassic epoch in the geologic timescale, or the lowest stage of the Lower Triassic series in chronostratigraphy. It spans the time between 251.9 Ma and 249.9 Ma (million years ago). The Induan is so ...
and
Olenekian
In the geologic timescale, the Olenekian is an age (geology), age in the Early Triassic epoch (geology), epoch; in chronostratigraphy, it is a stage (stratigraphy), stage in the Lower Triassic series (stratigraphy), series. It spans the time betw ...
ages. The fossils of these crocodile-shaped amphibians were found in
Greenland
Greenland is an autonomous territory in the Danish Realm, Kingdom of Denmark. It is by far the largest geographically of three constituent parts of the kingdom; the other two are metropolitan Denmark and the Faroe Islands. Citizens of Greenlan ...
,
Spitsbergen
Spitsbergen (; formerly known as West Spitsbergen; Norwegian language, Norwegian: ''Vest Spitsbergen'' or ''Vestspitsbergen'' , also sometimes spelled Spitzbergen) is the largest and the only permanently populated island of the Svalbard archipel ...
,
Pakistan
Pakistan, officially the Islamic Republic of Pakistan, is a country in South Asia. It is the List of countries and dependencies by population, fifth-most populous country, with a population of over 241.5 million, having the Islam by country# ...
and
Madagascar
Madagascar, officially the Republic of Madagascar, is an island country that includes the island of Madagascar and numerous smaller peripheral islands. Lying off the southeastern coast of Africa, it is the world's List of islands by area, f ...
.
* Reptiles: In the oceans, the first marine reptiles appeared during the Early Triassic.
Their descendants ruled the oceans during the Mesozoic.
Hupehsuchia,
Ichthyopterygia
Ichthyopterygia ("fish flippers") was a designation introduced by Richard Owen, Sir Richard Owen in 1840 to designate the Jurassic ichthyosaurs that were known at the time, but the term is now used more often for both true Ichthyosauria and their ...
and
sauropterygians are among the first marine reptiles to enter the scene in the Olenekian (e.g. ''
Cartorhynchus'', ''
Chaohusaurus'', ''
Utatsusaurus
''Utatsusaurus hataii'' is the earliest-known ichthyopterygian which lived in the Early Triassic period (c. 245â250 million years ago). It was nearly long with a slender body. The first specimen was found in Utatsu-cho (now part of Minamisa ...
'', ''
Hupehsuchus'', ''
Grippia
''Grippia'' is a genus of early ichthyopterygian, an extinct group of reptiles that resembled dolphins. Its only species is ''Grippia longirostris''. It was a relatively small ichthyopterygian, measuring around long. Fossil remains from Svalba ...
'', ''
Omphalosaurus'', ''
Corosaurus''). Other marine reptiles such as ''
Tanystropheus'', ''
Helveticosaurus'', ''
Atopodentatus'',
placodont
Placodonts (" tablet teeth") are an extinct order of marine reptiles that lived during the Triassic period, becoming extinct at the end of the period. They were part of Sauropterygia, the group that includes plesiosaurs. Placodonts were generall ...
s or the
thalattosaurs followed later in the Middle Triassic.
The
Anisian
In the geologic timescale, the Anisian is the lower stage (stratigraphy), stage or earliest geologic age, age of the Middle Triassic series (stratigraphy), series or geologic epoch, epoch and lasted from million years ago until million years ag ...
aged
ichthyosaur
Ichthyosauria is an order of large extinct marine reptiles sometimes referred to as "ichthyosaurs", although the term is also used for wider clades in which the order resides.
Ichthyosaurians thrived during much of the Mesozoic era; based on fo ...
''
Thalattoarchon'' was one of the first marine macropredators capable of eating prey that was similar in size to itself, an ecological role that can be compared to that of modern
orca
The orca (''Orcinus orca''), or killer whale, is a toothed whale and the largest member of the oceanic dolphin family. The only extant species in the genus '' Orcinus'', it is recognizable by its black-and-white-patterned body. A cosmopol ...
s.
Fossil gallery
File:PMS - spodnjetriasni kaÄjerepi (Ophiuroidea).jpg, Early Triassic brittle star
Brittle stars, serpent stars, or ophiuroids (; ; referring to the serpent-like arms of the brittle star) are echinoderms in the class Ophiuroidea, closely related to starfish. They crawl across the sea floor using their flexible arms for locomot ...
s (echinoderms)
File:Claraia Clarai Museum GrĂśden.jpg, Fossils of the bivalve
Bivalvia () or bivalves, in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class (biology), class of aquatic animal, aquatic molluscs (marine and freshwater) that have laterally compressed soft bodies enclosed b ...
'' Claraia clarai''
File:Hedenstroemiidae_-_Hedenstroemia_tscherskii.JPG, Early Triassic ammonoid '' Hedenstroemia''
File:Candelarialepis argentus.png, Fossil of the Early Triassic neopterygian '' Candelarialepis argentus''
File:HupehsuchusNanchangensis-PaleozoologicalMuseumOfChina-May23-08.jpg, Early Triassic '' Hupehsuchus'' fossil in the Paleozoological Museum of China
The Paleozoological Museum of China (PMC; ) is a museum in Beijing, China. The same building also houses the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences. The museum contains exhibition halls with s ...
File:Erythrosuchus africanus 34.jpg, Skull of the Early Triassic archosauriform ''Erythrosuchus
''Erythrosuchus'' (from , 'red' and , 'crocodile') is an extinct genus of archosauriform reptiles from the early Triassic of South Africa. Remains have been found from the Cynognathus Assemblage Zone of the Beaufort Group in the Karoo of South ...
''
File:Lystrosaurus hedini.JPG, ''Lystrosaurus
''Lystrosaurus'' (; 'shovel lizard'; proper Ancient Greek is ''lĂstron'' âtool for leveling or smoothing, shovel, spade, hoeâ) is an extinct genus of herbivorous dicynodont therapsids from the late Permian and Early Triassic epochs (arou ...
hedini'' skeleton at the Museum of Paleontology in TĂźbingen
See also
*
Geologic time scale
The geologic time scale or geological time scale (GTS) is a representation of time based on the rock record of Earth. It is a system of chronological dating that uses chronostratigraphy (the process of relating strata to time) and geochro ...
*
Triassic
The Triassic ( ; sometimes symbolized đ) is a geologic period and system which spans 50.5 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.4 Mya. The Triassic is t ...
*
Mass extinction
An extinction event (also known as a mass extinction or biotic crisis) is a widespread and rapid decrease in the biodiversity on Earth. Such an event is identified by a sharp fall in the diversity and abundance of multicellular organisms. It occ ...
References
Further reading
*
External links
GeoWhen Database â Early Triassic(archived 2 January 2006)
{{Geological history, p, m
*01
Geological epochs
*01
de:Buntsandstein