''Pagetia'' Walcott, 1916. is a small genus of trilobite, assigned to the Eodiscinid family Pagetiidae and which had global distribution during the

Middle Cambrian Middle or The Middle may refer to: * Centre (geometry), the point equally distant from the outer limits. Places * Middle (sheading), a subdivision of the Isle of Man * Middle Bay (disambiguation) * Middle Brook (disambiguation) * Middle Creek ...

. The genus contains 55 currently recognized species, each with limited spatial and temporal ranges.

Type species

''Pagetia bootes'' Walcott, 1916, from the middle Cambrian (late

Wuliuan The Wuliuan stage is the fifth stage of the Cambrian, and the first stage of the Miaolingian Series of the Cambrian. It was formally defined by the ICS in 2018. Its base is defined by the first appearance of the trilobite species '' Oryctoceph ...

or base

Drumian The Drumian is a stage of the Miaolingian Series of the Cambrian. It succeeds the Wuliuan and precedes the Guzhangian. The base is defined as the first appearance of the trilobite '' Ptychagnostus atavus'' around million years ago. The top i ...

) Burgess Shale fossil Lagerstätte. The species occurs with ''

Ptychagnostus ''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 gen ...

praecurrens'' and derives originally from the "greater

phyllopod bed The Phyllopod bed, designated by USNM locality number 35k, is the most famous fossil-bearing member of the Burgess Shale fossil ''Lagerstätte''. It was quarried by Charles Walcott from 1911–1917 (and later named Walcott Quarry), and was t ...

" 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.

Taxonomy

Order: Agnostida Salter, 1864. Suborder: Eodiscina Kobayashi, 1939. Family: PAGETIIDAE Kobayashi 1935. Genus: Pagetia Walcott, 1916. (''op. cit''.).

Species previously assigned to Pagetia

* ''P. attleborensis'' = '' Hebediscus attleborensis'' * ''P. jinnanensis'' = '' Sinopagetia jinnanensis'' * ''P. maladensis'' = '' Macannaia maladensis'' * ''P. medicinalis'' (plant, Rutaceae) = ''

Bosistoa medicinalis ''Bosistoa medicinalis'', commonly known as the northern towra or Eumundi bosistoa, is a species of small to medium-sized rainforest tree that is endemic to Queensland. It has simple and pinnate leaves with two or three leaflets and panicles of ...

'' * ''P. monostylis'' (plant, Rutaceae) = ''

Description

A genus of the Family Pagetiidae and mainly differentiated from members of the

Eodiscidae Eodiscidae is a family of agnostid trilobites that lived during the final Lower Cambrian (late Toyonian) and the Middle Cambrian. They are small or very small, and have a thorax of two or three segments. Eodiscidae includes nine genera (see box). ...

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. 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.

Ontogeny

The

ontogenetic Ontogeny (also ontogenesis) is the origination and development of an organism (both physical and psychological, e.g., moral development), usually from the time of fertilization of the egg to adult. The term can also be used to refer to the st ...

(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 (

) Kaili Formation,

Guizhou Guizhou (; formerly Kweichow) is a landlocked province in the southwest region of the People's Republic of China. Its capital and largest city is Guiyang, in the center of the province. Guizhou borders the autonomous region of Guangxi to the ...

, southwestern China.

Ecology

Several species of ''Pagetia'' are known from the

Burgess Shale 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 old (middle Cambrian), it is one of the earliest fo ...

. 1022 specimens of ''Pagetia'' are known from the Greater

Phyllopod bed The Phyllopod bed, designated by USNM locality number 35k, is the most famous fossil-bearing member of the Burgess Shale fossil ''Lagerstätte''. It was quarried by Charles Walcott from 1911–1917 (and later named Walcott Quarry), and was t ...

, where they comprise 1.94% of the community. and its remains have been found in the otherwise-empty tubes of the polychaete worm '' Selkirkia''.COPPOLD, MURRAY and POWELL (2006). ''A Geoscience Guide to the Burgess Shale'', p.56. The Burgess Shale Geoscience Foundation, Field, British Columbia. .

References

External links

* {{Taxonbar, from=Q7124337 Burgess Shale fossils Eodiscina Agnostida genera Cambrian trilobites Cambrian trilobites of Australia Fossils of China Fossils of Canada Fossils of Russia Fossil taxa described in 1916 Paleozoic life of Newfoundland and Labrador Paleozoic life of Quebec Cambrian genus extinctions