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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.
Bathyuriscus is an extinct genus of Cambrian trilobite. It was a nektobenthic predatory carnivore. The genus Bathyuriscus is endemic to the shallow seas that surrounded Laurentia. [3] Its major characteristics are a large forward-reaching glabella, pointed pleurae or pleurae with very short spines, and a medium pygidium with well-impressed ...
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 ...
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
A 2019 study of adult specimens with preserved soft tissue from the Burgess Shale found that agnostidans shared morphological similarities to trilobites and other related artiopodans like nektaspids, and their placement as stem-crustaceans was unsupported. The study recovered agnostidans as the sister group to other trilobites within the Artiopoda.
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 ...
Paraphillipsia is a genus of proetid trilobite in the family Phillipsiidae. [1] [2] It is notable for being one of the last trilobites to go extinct during the Permian–Triassic extinction event. [3]
In other trilobites, dorsal sutures may be opisthoparian, gonatoparian, proparian or they may be lost secondarily. The absence in the fossil record of the earliest larval stage, the protaspid, suggests that it may have been uncalcified, which would be a second unique character that distinguishes the Olenellina from all other trilobites.