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Topic: Proetida

Related Topics

Ptychopariida

Corynexochida

Lichida

Nektaspida

Harpetida

Phacopida

Asaphida

Agnostida

Redlichiida

	PROETIDA FACT SHEET
		The family Proetidae can not be readily derived from that ancestor, suggesting another sister group among the late Cambrian ptychoparioids may be responsible.
		The status of the order Proetida introduced by Fortey and Owens (1975) has been questioned by Bergström (1977) who pointed out that many characters used for the original definition of the order Proetida were general characters seen in many other trilobite taxa.
		This particular ontogeny is characterized by bubble-shaped and almost smooth anaprotaspides bearing three pairs of marginal spines, associated with a particularly broad ovoid hypostome provided with at least one prominent postero-medial spine, and followed by a maximum of two almost smooth adult-like metaprotaspid stages.
	www.trilobites.info /ordproetida.htm (1168 words)

	Journal of Paleontology: Ontogenies of some Ordovician Telephinidae from Argentina, and larval patterns in the Proetida ...
		These larval types are important for understanding the systematics and life cycles of the Proetida.
		The best larval synapomorphy for the Proetida is the distinctive metaprotaspid larval type, which is absent in very few proetides (some Telephinidae), perhaps as a result of heterochronic displacement of this stage into the meraspid period.
		Some of the most important arguments in favor of the Proetida as a natural group are based on similarities of small growth stages.
	www.findarticles.com /p/articles/mi_qa3790/is_199903/ai_n8843427 (1336 words)

	In order to distinguish trilobites from one another
		, and Proetida have in common species with a natant hypostomal condition.
		The recognition of Asaphida, Proetida, and Harpetida as orders is relatively recent, as in the 1959 Treatise they were all included within the very large order Ptychopariida.The Ptychopariida and Harpetida maintained the natant state until their extinction at the end of the
		The great extinction event at the end of the Ordovician period greatly affected trilobites, as this caused the extinction of the Olenina order, Agnostida order, and the vast majority of the Asaphida order.
	www.k12.nf.ca /gc/Science/Geology03/trilobites/Orders.htm (564 words)

	High Level Trilobite Systematics (Site not responding. Last check: 2007-10-14)
		The last four orders listed – Ptychopariida, Harpetida, Asaphida and Proetida – share (at least in primitive forms) a natant hypostomal condition, leading Fortey 1990 to propose a phylogenetic relationship between these forms and a new subclass, Libristoma, to group them.
		A subclass-level organisation for the remaining orders has not emerged.
		In 1975, several member groups of the Illaenina were reassigned to a newly erected order, Proetida, by Richard Fortey and R. Owens (Fortey and Owens 1975).
	www.peripatus.gen.nz /Taxa/Arthropoda/Trilobita/TriSys.html (2651 words)

	Bathyurus extans Trilobite Canada
		Description: A fine example of a member of the Order Proetida, Family Bathyuidae, this is Bathyurus extans.
		This trilobite is a member of the last surviving order of trilobites, the Proetida.
		It has the characteristic swept-back genals, one of which is partially obscured.
	www.fossilmall.com /EDCOPE_Enterprises/trilobites/Trilobite-36/Trilobite-36.htm (152 words)

	Palaeos Invertebrates : Arthropoda : Trilobita : Harpetida Fact Sheet (Site not responding. Last check: 2007-10-14)
		Fortey erected the Librostoma (1990) to act as a high-level monophyletic group containing all of the "ptychopariid" (sensu Treatise 1959) orders and suborders.
		As Proetida, Asaphida, and now Harpetida are distinguished from the old Ptychopariida clade, the subclass Librostoma serves to highlight the shared Ptychoparioid ancestry.
		A note on the name Harpidae: Harpidae was once used as the name for the trilobite family containing the type genus Harpes.
	www.palaeos.com /Invertebrates/Arthropods/Trilobita/Harpetida.html (316 words)

	Mahaska County Conservation - News - Article
		The smallest known trilobite species is just under a millimeter long, while the largest include species from one to two feet long.
		The Phillipsia trilobites of the order Proetida are the type found in the Ste.
		These are tiny compared to other trilobites known from Iowa, only about 1/4 inch long.
	www.mahaskaconservation.com /newsletter/article.php?id=25 (199 words)

	Journal of Paleontology: Ontogeny and systematics of Toernquistiidae (Trilobita, Proetida) from the Ordovician of the ...
		Journal of Paleontology: Ontogeny and systematics of Toernquistiidae (Trilobita, Proetida) from the Ordovician of the Argentine Precordillera
		Ontogeny and systematics of Toernquistiidae (Trilobita, Proetida) from the Ordovician of the Argentine Precordillera
		Journal of Paleontology, Mar 1998 by Chatterton, Brian D E, Edgecombe, Gregory D, Waisfeld, Beatriz G, Vaccari, Norberto E
	www.findarticles.com /p/articles/mi_qa3790/is_199803/ai_n8793729/pg_13 (652 words)

	paleolab9trilobites
		Only two orders survived the Late -Devonian extinction events, the Phacopida and the Proetida.
		These two orders continued through late Paleozoic time, although became only a rare component of the marine benthic fauna, and typically associated with reef environments.
		The Order Proetida was the last group of trilobites to survive through the Paleozoic, becoming extinct in the Permo-Triassic extinction events.
	www.personal.kent.edu /~alisonjs/paleo/paleolab9trilobites.htm (854 words)

	Among My Trilobites (Site not responding. Last check: 2007-10-14)
		Yahoo Trilobite Club member Sam Gon III has done a great job of presenting the salient points of current trilobite classification according to his synthesis of the current, but incomplete Treatise on Invertebrate Paleontology with its 1959 predecessor, the original Treatise.
		The list of orders includes: Agnostida, Redlichida, Corynexochida, Lichida, Phacopida, Proetida, Asaphida, and Ptychoparida.
		Most orders did not exist throughout the entire Paleozoic, but several did have members extending through several eras.
	www.nctimes.net /~tyra-rex/t.html (1089 words)

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