Ptychopariina is an extinct suborder of
trilobite
Trilobites (; meaning "three lobes") are extinct marine arthropods that form the class Trilobita. Trilobites form one of the earliest-known groups of arthropods. The first appearance of trilobites in the fossil record defines the base of the ...
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–Silurian ...
.
[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–Silurian ...
'', they are a notably wide and varied
taxon
In biology, a taxon ( back-formation from '' taxonomy''; plural 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 n ...
.
Some of the representative
genera include ''
Elrathia
''Elrathia'' is a genus of trilobite belonging to Ptychopariacea known from the mid- Cambrian of Laurentia (North America). ''E. kingii'' is one of the most common trilobite fossils in the USA locally found in extremely high concentrations wit ...
'', ''
Densonella'', ''
Norwoodia'', ''
Tricrepicephalus'', ''
Conocoryphe'', and ''
Modocia''.
Description
Specialization
Specialization or Specialized may refer to:
Academia
* Academic specialization, may be a course of study or major at an academic institution or may refer to the field in which a specialist practices
* Specialty (medicine), a branch of medical ...
is common in the Ptychopariina, which has made it difficult for authors to develop a single
type that can distinguish Ptychopariina from other
clades. 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