| Norasaphus monroeae Temporal range: Arenig | |
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| Species: | N. monroeae |
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| Norasaphus monroeae | |
Norasaphus monroeae is a species of asaphid trilobites named after Marilyn Monroe for its hourglass-like shaped glabellum. [2] [3] [4] Its fossils are found in Arenig-aged marine strata from the Nora Formation, in the Georgina Basin, situated between the Northern Territory and Queensland, Australia.
Trilobites are extinct marine arthropods that form the class Trilobita. Trilobites form one of the earliest known groups of arthropods. The first appearance of trilobites in the fossil record defines the base of the Atdabanian stage of the Early Cambrian period and they flourished throughout the lower Paleozoic before slipping into a long decline, when, during the Devonian, all trilobite orders except the Proetida died out. The last extant trilobites finally disappeared in the mass extinction at the end of the Permian about 251.9 million years ago. Trilobites were among the most successful of all early animals, existing in oceans for almost 270 million years, with over 22,000 species having been described.
Richard Alan Fortey is a British palaeontologist, natural historian, writer and television presenter, who served as president of the Geological Society of London for its bicentennial year of 2007.
Dalmanites is a genus of trilobite in the order Phacopida. They lived from the Late Ordovician to Middle Devonian.
Walliserops is a genus of spinose phacopid trilobite, of the family Acastidae, found in Lower to Middle Devonian age rocks from the Anti-Atlas Mountains of Morocco. All species of Walliserops possess a three-pronged "trident" that protrudes from the glabella. Walliserops is most closely related to the genus Comura.
Cloacaspis is an extinct genus of Olenid Ptychopariid trilobite. It lived during the early part of the Arenig stage of the Ordovician Period, a faunal stage which lasted from approximately 478 to 471 million years ago. Richard Fortey has proposed that these particular trilobites lived in anoxic regions of the ocean floor, and cultivated symbiotic, sulfur-metabolizing bacteria.
Chelediscus Rushton, 1966, is a genus of Eodiscinid trilobite belonging to the family Weymouthiidae Kobayashi T. (1943), Order Agnostida Salter (1864). The Treatise assigns this genus to the Calodiscidae; Cotton and Fortey (2005) however move it to the Weymouthiidae. Chelediscus lived during the later part of the Botomian stage.
Pytine is an extinct genus of asaphid trilobites. Species lived during the later part of the Arenig stage of the Ordovician Period, approximately 478 to 471 million years ago. Various species are found in the Svalbard, Valhallfonna Formation, Olenidsletta, Member, of Spitzbergen, Norway, the Megistaspis (Paramegistaspis) planilimbata Zone of the 'Shumardia Shale' of Sweden, Jujuy Province, Argentina, early Arenig-aged strata of Jiangxi province, China, and Darriwilian-aged strata in Western Hunan province, China. The type species, P. graia, has seven thorax segments, and lacks the rapier-like glabellar spine, that occurs in many other raphiophorids. The Chinese species, by contrast, have only six thoracic segments. So far, only the type species, and one of the Chinese species, P. laevigata, are known from complete specimens.
Erbenochile is a genus of spinose phacopid trilobite, of the family Acastidae, found in Lower to Middle Devonian age rocks from Algeria and Morocco. Originally described from an isolated pygidium, the first complete articulated specimen of E. erbeni revealed the presence of extraordinarily tall eyes:
"Straight-sided towers of lenses... with [up to] 18 lenses in a vertical file"
Cheirurus is a genus of phacopid trilobites that lived from the Ordovician to the Devonian. Its remains have been found in Africa, Asia, Australia, Europe, and North America. Cheirurus is the type genus of Cheiruridae.
Acernaspis is an extinct genus of trilobite that is known from the Silurian. It contains two species, A. elliptifrons, and A. salmoensis. It is sometimes found preserved in burrows of various forms, sometimes in association with multiple moults, suggesting that it used tunnels as refuges whilst in its vulnerable moulting stage.
Brianurus is a genus of Silurian trilobites known from Canada. It was originally described from the Whittaker Formation. It is named after Professor Brian D. E. Chatterton from the University of Alberta.
The cephalon is the head section of an arthropod. It is a tagma, i.e., a specialized grouping of arthropod segments. The word cephalon derives from the Greek κεφαλή (kephalē), meaning "head".
Buenaspis is a genus of small nektaspid arthropod, that lived during the early Cambrian period. Fossil remains of Buenaspis were collected from the Lower Cambrian Sirius Passet Lagerstätte of North Greenland. Buenaspis looks like a soft eyeless trilobite. It has a headshield slightly larger than the tailshield (pygidium), and in between them six thoracic body segments (somites). The genus is monotypic, its sole species being Buenaspis forteyi.
Annamitella Mansuy 1916 is a genus of trilobite, extinct marine arthropods. Annamitella lived from the Arenig to the Llandeilo age of the Ordovician Period from 478.6 to 460.9 million years ago.
Trinodus is a very small to small blind trilobite, a well known group of extinct marine arthropods, which lived during the Ordovician, in what are now the Yukon Territories, Virginia, Italy, Czech Republic, Poland, Denmark, Sweden, Svalbard, Ireland, Scotland, Wales, Iran, Kazakhstan and China. It is one of the last of the Agnostida order to survive.
Prospectatrix is a genus of trilobites of average size, that lived in the Lower Ordovician and is probably ancestral to the other genera of the Cyclopygidae family. Its eyes are only moderately enlarged and it has six or seven thorax segments.
Carolinites is a genus of trilobite, assigned to the Telephinidae family, that occurs during the Lower and Middle Ordovician. Carolinites had a pantropical distribution, and there is evidence that it lived in upper parts of the water column. The free cheeks of Carolinites are largely covered by its huge eyes, except for the attachment of large genal spines that extend downward, backward and lateral and gradually curving further backward. The glabella is slightly bulbous, the occipital ring is well defined, but further transglabellar furrows are lacking. The thorax has 10 segments. The axis of the pygidium is highly vaulted, with a curved spine emerging almost perpendicular to the midline and ending parallel to it and a node on each of the other three segments. Carolinites is known from what are today Australia (Tasmania), Canada (Alberta), China, France, Spitsbergen, and the United States (Utah).
Raphiophoridae is a family of small to average-sized trilobites that first occurred at the start of the Ordovician and became extinct at the end of the Middle Silurian.
A trilobite is a type of extinct marine arthropod.
Aponileus is an extinct genus of trilobites. Chung-Hung Hu circumscribed the genus in 1963. The genus was once considered a junior subjective synonym of the genus Psephosthenaspis but it is considered to be a distinct genus again. As of 2021, fossils have been found in Greenland, Texas, and Utah. They all date to the Upper Floian (Blackhillsian) within the Ordovician Period.
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