In 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 geochronol ...
, the Middle Triassic is the second of three
epochs of the
Triassic period or the middle of three
series in which the Triassic
system
A system is a group of Interaction, interacting or interrelated elements that act according to a set of rules to form a unified whole. A system, surrounded and influenced by its environment (systems), environment, is described by its boundaries, ...
is divided in
chronostratigraphy. The Middle Triassic spans the time between
Ma and Ma (million years ago). It is preceded by the
Early Triassic Epoch and followed by the
Late Triassic Epoch. The Middle Triassic is divided into the
Anisian and
Ladinian ages Ages may refer to:
*Advanced glycation end-products, known as AGEs
*Ages, Kentucky, census-designated place, United States
* ''Ages'' (album) by German electronic musician Edgar Froese
*The geologic time scale, a system of chronological measuremen ...
or
stages
Stage or stages may refer to:
Acting
* Stage (theatre), a space for the performance of theatrical productions
* Theatre, a branch of the performing arts, often referred to as "the stage"
* ''The Stage'', a weekly British theatre newspaper
* S ...
.
Formerly the middle series in the Triassic was also known as
Muschelkalk. This name is now only used for a specific unit of
rock strata
In geology and related fields, a stratum ( : strata) is a layer of rock or sediment characterized by certain lithologic properties or attributes that distinguish it from adjacent layers from which it is separated by visible surfaces known as ei ...
with approximately Middle Triassic age, found in western Europe.
Middle Triassic fauna
Following the
Permian–Triassic extinction event, the most devastating of all mass-extinctions, life recovered slowly. In the Middle Triassic, many groups of organisms reached higher diversity again, such as the marine
reptiles
Reptiles, as most commonly defined are the animals in the Class (biology), class Reptilia ( ), a paraphyletic grouping comprising all sauropsid, sauropsids except birds. Living reptiles comprise turtles, crocodilians, Squamata, squamates (lizar ...
(e.g.
ichthyosaurs,
sauropterygians
Sauropterygia ("lizard flippers") is an extinct taxon of diverse, aquatic reptiles that developed from terrestrial ancestors soon after the end-Permian extinction and flourished during the Triassic before all except for the Plesiosauria became ...
,
thallatosaurs),
ray-finned fish and many
invertebrate groups like
mollusc
Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is esti ...
s (
ammonoids,
bivalves
Bivalvia (), in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of marine and freshwater molluscs that have laterally compressed bodies enclosed by a shell consisting of two hinged parts. As a group, bival ...
,
gastropods).
During the Middle Triassic, there were no flowering plants, but instead there were ferns and mosses. Small dinosauriforms began to appear, like ''
Nyasasaurus'' and the ichnogenus ''
Iranosauripus
''Iranosauripus'' is an ichnogenus of dinosaur footprint discovered in Iran that supposedly belonged to a theropod. ''Iranosauripus'' supposedly existed during Middle Triassic-Early Jurassic, although the first true dinosaurs, such as ''Eoraptor'' ...
''.
File:Mixosaurus BW.jpg, ''Mixosaurus cornalianus
''Mixosaurus'' is an extinct genus of Middle Triassic (Anisian to Ladinian, about 250-240 Mya) ichthyosaur. Its fossils have been found near the Italy– Switzerland border and in South China.
The genus was named in 1887 by George H. Baur. ...
'' restoration, a Middle Triassic ichthyosaur
References
GeoWhen Database - Middle Triassic
*02
Geological epochs
*02
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