Ptychopariina is an extinct suborder of
trilobite
Trilobites (; meaning "three-lobed entities") are extinction, extinct marine arthropods that form the class (biology), class Trilobita. One of the earliest groups of arthropods to appear in the fossil record, trilobites were among the most succ ...
s of the order
Ptychopariida
Ptychopariida is a large, heterogeneous order of trilobite containing some of the most primitive species known. The earliest species occurred in the second half of the Lower Cambrian, and the last species did not survive the Ordovician–Siluria ...
.
[Swinnerton HH, 1915. Suggestions for a Revised Classification of trilobites. ''Geological Magazine''.] Also known as the ''primitive
Ptychopariida
Ptychopariida is a large, heterogeneous order of trilobite containing some of the most primitive species known. The earliest species occurred in the second half of the Lower Cambrian, and the last species did not survive the Ordovician–Siluria ...
'', they are a notably wide and varied
taxon
In biology, a taxon (back-formation from ''taxonomy''; : taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular name and ...
.
Some of the representative
genera
Genus (; : genera ) is a taxonomic rank above species and below family as used in the biological classification of living and fossil organisms as well as viruses. In binomial nomenclature, the genus name forms the first part of the binomial s ...
include ''
Elrathia'', ''
Densonella'', ''
Norwoodia'', ''
Tricrepicephalus'', ''
Conocoryphe'', and ''
Modocia''.
Description
Specialization is common in the Ptychopariina, which has made it difficult for authors to develop a single
type
Type may refer to:
Science and technology Computing
* Typing, producing text via a keyboard, typewriter, etc.
* Data type, collection of values used for computations.
* File type
* TYPE (DOS command), a command to display contents of a file.
* ...
that can distinguish Ptychopariina from other
clade
In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...
s. The thorax tends to be relatively long, with the pygidium generally smaller in size than the thorax.
References
External links
''Ptychopariida fact sheet'' (trilobites.info)*
Ptychopariina'
*
Ptychopariina'
Cambrian trilobites
Ptychopariida
Arthropod suborders
{{Ptychopariida-stub