| Pagetia Temporal range: | |
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| A heavily eroded specimen of Pagetia taijiangensis, 6 mm, from Kaili, Guizhou, China | |
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| Genus: | Pagetia |
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Eopagetia, Mesopagetia | |
Pagetia is a genus of small trilobite, assigned to the Eodiscinid family Pagetiidae and which had global distribution during the Middle Cambrian. The genus contains 55 currently recognized species, each with limited spatial and temporal ranges.
Pagetia bootes Walcott, 1916, from the middle Cambrian (late Wuliuan or base Drumian) Burgess Shale fossil Lagerstätte. The species occurs with Ptychagnostus praecurrens and derives originally from the "greater phyllopod bed" of Walcott quarry on "Fossil Ridge" between Wapta Mountain and Mount Field, approximately 5 kilometres north of Field, British Columbia in the Canadian Rocky Mountains. The presence of Pt. praecurrens, indicates correlation with the Swedish praecurrens Biozone (Baltoparadoxides pinus Biosubzone, A2 of Westergård 1946, pp. 98–100) in the upper part of the oelandicus Superzone. [5]
Order: Agnostida Salter, 1864. [6] Suborder: Eodiscina Kobayashi, 1939. [7] Family: PAGETIIDAE Kobayashi 1935. Genus: Pagetia Walcott, 1916. (op. cit.).
A genus of the Family Pagetiidae and mainly differentiated from members of the Eodiscidae in having eyes and proparian facial sutures. In the type species, Pagetia bootes Walcott, 1916, there is a well-defined preglabellar median furrow separating the genae. Glabella is well defined, tapers slightly forward and has a well developed spine extending rearwards from the glabella. Anterior border is crenulated, which is common amongst both Eodiscidae and Pagetiidae. No genal spines. Thorax of two segments; pleurae fulcrate with anterior pleural tips pointing backwards and those of the posterior segment directed forwards to enable enrolment. Pygidial axis is well defined, reaching or overhanging the posterior border, usually with five rings and commonly extending backwards into a prominent postaxial spine. [8]
The hypostome is a convex subquadrate plate, positioned directly under frontal part of the glabella. It is comparable to the hypostoma of other trilobites and provides an argument that Agnostida can be regarded as specialized, simplified trilobites. [9]
The ontogenetic (or growth) series of Pagetia vinusta Lu and Qian in Lu et al., 1974 was described in a research paper by Cui et al. (2019) on the basis of numerous articulated individuals and many disarticulated sclerites from the Cambrian (Wuliuan) Kaili Formation, Guizhou, southwestern China. [10]
Several species of Pagetia are known from the Burgess Shale. 1022 specimens of Pagetia are known from the Greater Phyllopod bed, where they comprise 1.94% of the community. [11] and its remains have been found in the otherwise-empty tubes of the polychaete worm Selkirkia . [12] [13]
The Burgess Shale is a fossil-bearing deposit exposed in the Canadian Rockies of British Columbia, Canada. It is famous for the exceptional preservation of the soft parts of its fossils. At 508 million years old, it is one of the earliest fossil beds containing soft-part imprints.
Marrella is an extinct genus of marrellomorph arthropod known from the middle Cambrian Burgess Shale of British Columbia. It is the most common animal represented in the Burgess Shale, with tens of thousands of specimens collected. Much rarer remains are also known from deposits in China.
Wiwaxia is a genus of soft-bodied animals that were covered in carbonaceous scales and spines that protected it from predators. Wiwaxia fossils – mainly isolated scales, but sometimes complete, articulated fossils – are known from early Cambrian and middle Cambrian fossil deposits across the globe. The living animal would have measured up to 5 cm (2 inch) when fully grown, although a range of juvenile specimens are known, the smallest being 2 millimetres (0.079 in) long.
Sidneyia is an extinct arthropod known from fossils found from the Early to the Mid Cambrian of China and the Mid Cambrian Burgess Shale of British Columbia, Canada.
Ottoia is a stem-group archaeopriapulid worm known from Cambrian fossils. Although priapulid-like worms from various Cambrian deposits are often referred to Ottoia on spurious grounds, the only clear Ottoia macrofossils come from the Burgess Shale of British Columbia, which was deposited 508 million years ago. Microfossils extend the record of Ottoia throughout the Western Canada Sedimentary Basin, from the mid- to late- Cambrian. A few fossil finds are also known from China.
Choia is a genus of extinct demosponge ranging from the Cambrian until the Lower Ordovician periods. Fossils of Choia have been found in the Burgess Shale in British Columbia; the Maotianshan shales of China; the Wheeler Shale in Utah; and the Lower Ordovician Fezouata formation. It was first described in 1920 by Charles Doolittle Walcott.
Olenoides was a trilobite from the Cambrian period. Its fossils are found well-preserved in the Burgess Shale in Canada. It grew up to 10 cm long.
Acidiscus Rasetti, 1966, is a genus of Eodiscinid trilobite belonging to the family Weymouthiidae Kobayashi T. (1943), Order Agnostida Salter (1864). It lived during the Botomian stage = late Lower Cambrian Stage 4 ; the upper Botomian boundary corresponds to base of the Middle Cambrian, Miaolingian Series and Wuliuan stage.
Acimetopus Rasetti, 1966, is a genus of Eodiscinid trilobite belonging to the family Weymouthiidae Kobayashi (1943), Order Agnostida Salter (1864). It lived during the Botomian stage. = late Lower Cambrian Stage 4 ; the upper Botomian boundary corresponds to base of the Middle Cambrian, Miaolingian Series and Wuliuan stage.
Analox Rasetti, 1966 is a genus of Eodiscinid trilobites belonging to the family Weymouthiidae Kobayashi T. (1943), Order Agnostida It lived during the Botomian stage. It can easily be distinguished from other trilobites by the two furrows that extend forwards and sidewards from the front of the glabella.
Stigmadiscus Rasetti, 1966, is a genus of Lower Cambrian Eodiscinid trilobite belonging to the family Weymouthiidae Kobayashi (1943) Order Agnostida It lived during the Botomian stage, = late Lower Cambrian Stage 4 ; the upper Botomian Stage boundary corresponds to base of both the Middle Cambrian Wuliuan stage and Miaolingian Series.
Tsunyidiscus is a trilobite belonging to the Suborder Eodiscina. Tsunyidiscus appeared near the end of the Lower Cambrian, during the late Atdabanian stage of geologic time and some collections suggest it may have survived into the Botomian. The genus is very small, oculate and isopypous with a narrow dome-shaped glabella and a narrow bullet-shaped pygidial axis. Thorax consists of three segments. Tsunyidiscus is the only genus currently attributed to the family Tsunyidiscidae.
Helmetia is an extinct genus of arthropod from the middle Cambrian. Its fossils have been found in the Burgess Shale of Canada and the Jince Formation of the Czech Republic.
Hurdia is an extinct genus of hurdiid radiodont that lived 505 million years ago during the Cambrian Period. Fossils have been found in North America, China and the Czech Republic.
Emeraldella is a genus of arthropod known from the Middle Cambrian of North America. The type species E. brocki was described in 1912 from the Burgess Shale. 21 specimens of Emeraldella are known from the Greater Phyllopod bed, where they comprise < 0.1% of the community. A re-study on the species was done in 2012. A second species E. brutoni is known from the Wheeler Shale, which was described in 2011. An additional specimen of E. brutoni was described in 2019, which revealed more of the anatomy. It has been placed as a basal member of the clade Vicissicaudata within Artiopoda, a group of arthropods containing trilobites and their relatives.
Ptychagnostus is a member of the agnostida that lived during the Cambrian period. Ptychagnostidae generally do not exceed one centimetre in length. Their remains are rarely found in empty tubes of the polychaete worm Selkirkia. The genus probably ranged throughout the water column. It has two glabellar lobes, and three pygidial lobes.
The Marjum Formation is a Cambrian geological formation that overlies the Wheeler Shale in the House Range, Utah. It is named after its type locality, Marjum Pass, and was defined in 1908. The formation is known for its occasional preservation of soft-bodied tissue, and is slightly younger than the Burgess Shale, falling in the Ptychagnostus praecurrens trilobite zone.
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. Its major characteristics are a large forward-reaching glabella, pointed pleurae or pleurae with very short spines, and a medium pygidium with well-impressed furrows. Complete specimens have never reached the size of 7 cm predicted by the largest pygidium found. Bathyuriscus is often found with the free cheeks shed, indicating a moulted exoskeleton. An average specimen will in addition have a furrowed glabella, crescent-shaped eyes, be semi-circular in overall body shape, have 7 to 9 thoracic segments, and a length of about 1.5 inches.
Eodiscina is trilobite suborder. The Eodiscina first developed near the end of the Lower Cambrian period and became extinct at the end of the Middle Cambrian. Species are tiny to small, and have a thorax of two or three segments. Eodiscina includes six families classified under one superfamily, Eodiscoidea.
Ptychagnostidae is a family of agnostid trilobites from the 5th Stage to the Paibian Age of the Cambrian. The family includes several important index fossils.