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Asaphiscus wheeleri, a trilobite from the Cambrian Wheeler shale of Utah. This list of trilobites is a comprehensive listing of all genera that have ever been included in the Arthropod class Trilobita, excluding purely vernacular terms.
The females and larvae have a flattened, dark body with large scales over the head, resembling trilobites, hence the informal names trilobite beetle, trilobite larva or Sumatran trilobite larva. In contrast, the males are much smaller, 8–9 mm, resembling other lycid beetles. Species are found in tropical forests of India and South-east Asia.
Trilobite exoskeletons show a variety of small-scale structures collectively called prosopon. Prosopon does not include large scale extensions of the cuticle (e.g. hollow pleural spines) but to finer scale features, such as ribbing, domes, pustules, pitting, ridging and perforations.
Shallow shelf trilobite faunas were hit particularly hard. Trilobites that inhabited the outer edges of shelf environments and slope environments, on the other hand, were minimally impacted by the event. [1] Many trilobites appear to have been adapted to the anoxic conditions of the Cambrian through symbiosis with the sulfur-oxidizing bacteria. [6]
A natant hypostome is not attached to the anterior doublure, with support assumed to be provided by a non-mineralised membrane.Natant hypostomes appear to have been conservative over the course of the evolution of trilobites [2] with overall form and shape of a simple ovoid without posterior extensions or ornamentation. [1]
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.
Balnibarbi is an extinct genus of trilobites in the family Olenidae. They are known from fossils excavated in Norway. They lived during the early part of the Arenig stage of the Ordovician Period, a faunal stage that occurred about 479 to 472 million years ago. [2] The genus is ancestral to, and co-existed sympatrically with, the better-known ...
Cotton & Braddy (2000) place it in a new "Trilobite clade" containing the Trilobita, recognizing the close affinities of the nektaspids to trilobites. However this necessitates the inclusion of genera that look very little like trilobites., [ 4 ] it was formerly placed in the stem-group to the chelicerata subdivision of the Arthropoda phylum. [ 5 ]