Ptychoparioidea

	Ptychoparioidea Ptychoparioidea is a superfamily of the Ptychopariida order of trilobites.Pour M. G., Popov L. E. (2009) Silicified Middle Cambrian trilobites from Kyrgyzstan, Palaeontology, 1039-1056 Taxonomy Family Acrocephalitidae Family Alokistocaridae Family Antagmidae Family Asaphiscidae Family Atopidae Family Bolaspididae Family Cedariidae Family Changshaniidae Family Conocoryphidae Family Conokephalinidae Family Crepicephalidae Family Diceratocephalidae Family Elviniidae Family Eulomidae Family Holocephalinidae Family Ignotogregatidae Family Inouyiidae Family Isocolidae Family Kingstoniidae Family Liostracinidae Family Llanoaspididae Family Lonchocephalidae Family Lorenzellidae Family Mapaniidae Family Marjumiidae Family Menomoniidae Family Nepeidae Family Norwoodiidae Family Papyriaspididae Family Phylacteridae Family Proasaphiscidae Family Ptychopariidae Ptychopariidae is a family of trilobites, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	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 extinction event. 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. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Nepeidae The Nepeidae are a family of trilobites, that lived during the late Middle Cambrian - earliest Upper Cambrian in what are today Australia, Antarctica, China and New Zealand. The Nepeidae can be recognized by a vaulted area between the front of the glabella and the frontal border, eye ridges that extend outward and slightly forward from the front of the glabella, and fixed cheeks that cut into the free cheeks at the inside of the eye, and that extend backwards, forming the inner base of the genal spines. The genal spines, however, are part of the free cheeks and extend backward at least half the length of the thorax. The thorax has at least 20 segments. The tail shield (or pygidium The pygidium (plural pygidia) is the posterior body part or shield of crustaceans and some other arthropods, such as insects and the extinct trilobites. In groups other than insects, it contains the anus and, in females, the ovipositor. It is compo ...) is small. References Ptychoparioidea Tril ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Alokistocaridae Alokistocaridae is a family of ptychopariid trilobites that lived from the Botomian epoch of the Early Cambrian until the Late Cambrian. Alokistocarids were particle feeders and left small furrows which are occasionally preserved.Coppold, Murray and Wayne Powell (2006). ''A Geoscience Guide to the Burgess Shale'', p.54. The Burgess Shale Geoscience Foundation, Field, British Columbia. . Their remains are found worldwide. ''Elrathia kingii'', one of the most collected trilobites in the world, is a typical alokistocarid. Description Alokistocarids have an exoskeleton that is elongated ovate to inverted egg-shaped. The headshield (or cephalon) is semicircular and has a well-defined border. The central raised area of the cephalon (or glabella) is somewhat tapering forward, generally with 3 or 4 pairs of more or less distinct lateral furrows. The front of the glabella is rounded or truncate, and is separated from the border by a wide, moderately convex to flat (or rarely concave) so- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]