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 extinction event.
Asaphiscus wheeleri, a Cambrian trilobite of the Superfamily Ptychoparioidea
Trilobites have facial sutures that run along the margin of the glabella and/or fixigena to the shoulder point where the cephalon meets the thorax. These sutures outline the cranidium, or the main, central part of the head that does not include the librigena (free cheeks). The eyes are medial along the glabella on the suture line (and some species have no eyes). The fossils of the moults of trilobites can often be told from the fossils of the actual animals by whether the librigena are present. (The librigena, or cheek spines, detach during moulting.) In ptychopariids, short bladelike genal spines are often present on the tips of the librigena.
The thorax is large and is typically made up of eight or more segments. The thorax is usually much longer than the pygidium, which is usually small. In some species the pygidium is outlined with a flat border.
The Subclass Librostoma was recently erected to encompass several related orders, including Ptychopariida, Asaphida, Proetida, Harpetida, and possibly Phacopida. These are now known as the "Librostome Orders". Trilobites of the orders Proetida, Harpetida, and of the family Damesellidae were originally placed in Ptychopariida.
Ptychopariida is a large, heterogeneous order of trilobite containing some of the most primitive species known. The earliest species occurred in the second...
diversified into the major orders that typified the Cambrian—Redlichiida, Ptychopariida, Agnostida, and Corynexochida. The first major crisis in the trilobite...
small. The families of Harpetida were formerly included in the order Ptychopariida, but were recently given their own order (Ebach & McNamara 2002). The...
on the taxonomy and localities of Ordovician trilobites (Trilobita: Ptychopariida: Illaenidae, Panderidae) of Leningrad Region". BarSU Herald. Biological...
record along with trilobites from the Redlichiida, Corynexochida, and Ptychopariida orders, and were highly diverse throughout the Cambrian. Agnostidan...
and planktonic forms like graptolites. The trilobites Agnostida and Ptychopariida completely died out, and the Asaphida were much reduced. Brachiopods...
Conocoryphidae is a family of trilobites within the order Ptychopariida. Members of this family have been recorded from the Cambrian to early Ordivician...
Diceratocephalidae is a family of trilobites belonging to the order Ptychopariida. Cyclolorenzella Diceratocephalus Fenghuangella Tholifrons Trigocephalus...
event. These typically small trilobites resemble those of the order Ptychopariida, from which the new order Proetida was separated in 1975 by Fortey and...
candidates for the first trilobites being librostomes in the order ptychopariida; and all post-Devonian trilobites being in the order proetida, whom...
2011. Archived from the original on 2020-11-12. Retrieved 2023-01-21. "Order Ptychopariida". A Guide to the Orders of Trilobites. Sam Gon III. 2009....
this order. The first representatives of the orders Corynexochida and Ptychopariida also appear very early on and may prove to be even earlier than any...
†Redlichiida Order †Lichida Order †Phacopida Order †Proetida Order †Ptychopariida Order †Isoxyida Order †Hymenocarina Order †Mollisoniida Order †Bradoriida...
Cambrian Period and disappeared (possibly by evolving into members of the Ptychopariida order) at the end of the middle Cambrian. Cephalon: Opisthoparian facial...
Yunnanocephalidae, although it is now thought the superfamily is within the Ptychopariida Agraulidae is a family of trilobites within the superfamily Ellipsocephaloidea...
Diaphanometopidae are thought to have been an early transitional group between the Ptychopariida ancestors and all other Phacopina. Diaphanometopidae, are found in the...
the Phacopida order and shares some characteristics with the order Ptychopariida, though it is not included in the subclass Librostoma. Phacopida was...
(2015). "Systematic revision of the genus Solenopleura Angelin, 1854, Ptychopariida, Trilobita, Cambrian Series 3". Annales de Paléontologie. 101 (3): 185–192...
Ptychoparioidea is a superfamily of the Ptychopariida order of trilobites. Family Acrocephalitidae Family Alokistocaridae Family Antagmidae Family Asaphiscidae...
trilobites in the fossil record as members of Redlichiina, although Ptychopariida and Eodiscina follow soon after. The suborder died out when the Lower...
and is the type genus of the family Ptychopariidae, and the order Ptychopariida. Fossils of the various species are found in Middle Cambrian-aged marine...
burlingiids. Early scholars tentatively positioned the burlingiids in the Ptychopariida. The burlingiids have many more characters in common with the Redlichiina...
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