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Exactly why the trilobites became extinct is not clear; with repeated extinction events (often followed by apparent recovery) throughout the trilobite fossil record, a combination of causes is likely. After the extinction event at the end of the Devonian period, what trilobite diversity remained was bottlenecked into the order Proetida.
Olenoides followed the basic structure of all trilobites — a cephalon (head shield), a thorax with seven jointed parts, and finally a semicircular pygidium. Its antennae were long, and curved back along its sides. Its thin legs show that it was no swimmer, instead crawling along the sea floor in search of prey.
The Artiopoda is a grouping of extinct arthropods that includes trilobites and their close relatives. It was erected by Hou and Bergström in 1997 [5] to encompass a wide diversity of arthropods that would traditionally have been assigned to the Trilobitomorpha. Trilobites, in part due to abundance of findings owing to their mineralized ...
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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 ...
Asaphellus is an extinct genus of trilobites reported from the Ordovician. It is seen in Argentina, Bolivia, Mexico, America, Algeria, Iran, Spain, Portugal, France, Great Britain, Czech Republic, Norway, Sweden and China. [1] [2] [3]
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.
The Mesonacinae comprise an extinct subfamily of trilobites that lived during the Botomian, found in North-America, Greenland and North-Western Scotland. The two genera in this subfamily are Mesonacis and Mesolenellus. [1]