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The trilobite body is divided into three major sections : 1 – cephalon; 2 – thorax; 3 – pygidium. Trilobites are so named for the three longitudinal lobes: 4 – right pleural lobe; 5 – axial lobe; 6 – left pleural lobe; the antennae and legs are not shown in these diagrams.
Most trilobites with this life history strategy lived in warm, low latitude waters, in which planktonic, non-adult like larvae may be ideal at surviving in. During the Ordovician-Silurian extinction event, the widespread onset of cold water conditions and anoxia may have instead favoured species that produced small numbers of large eggs, from ...
Pages in category "Trilobites of North America" The following 33 pages are in this category, out of 33 total. This list may not reflect recent changes. A.
Elrathia is a genus of trilobite belonging to Ptychopariacea known from the mid-Cambrian of Laurentia (North America). [2] E. kingii is one of the most common trilobite fossils in the USA [3] locally found in extremely high concentrations within the Wheeler Formation in the U.S. state of Utah. [4] E. kingii has been considered the most ...
Dalmanites is genus of trilobites with an average (about 8 centimetres or 3.1 inches long), moderately vaulted exoskeleton with an inverted egg-shaped outline (about 1.5× longer than wide). Its headshield (or cephalon ) is semicircular, with robust (genal) spines extending from the side of the cephalon back to approximately the 8th thorax segment.
Thysanopyge is an extinct genus from a well-known class of fossil marine arthropods, the trilobites.It lived in what is now South America during the early part of the Arenig stage of the Ordovician Period, [1] a faunal stage which lasted from approximately 478 to 471 million years ago.
Eldredgeops rana (formerly Phacops rana) is a species of trilobite from the middle Devonian period. Their fossils are found chiefly in the northeastern United States , and southwestern Ontario . Because of its abundance and popularity with collectors, Eldredgeops rana was designated the Pennsylvania state fossil by the state's General Assembly ...
Trinucleidae is a family of small to average size asaphid trilobites that first occurred at the start of the Ordovician and became extinct at the end of that period. It contains approximately 227 species divided over 51 genera in 5 subfamilies. [1] The most conspicuous character is the wide perforated fringe of the head.