Terreneuvian

The Terreneuvian is the lowermost and oldest series of the Cambrian geological system.[1] Its base is defined by the first appearance datum of the trace fossil Treptichnus pedum around 541 million years ago. Its top is defined as the first appearance of trilobites in the stratigraphic record around 521 million years ago.[2] This series was formally ratified by the International Commission on Stratigraphy in 2012.[3]

The Fortunian stage and presently unnamed Cambrian Stage 2 are the stages within this series. The Terreneuvian corresponds to the pre-trilobitic Cambrian.[4]

The name Terreneuvian is derived from Terre Neuve, a French name for the island of Newfoundland, Canada, where many rocks of this age are found, including the type section.[1][2]

Coordinates: 47°04′34″N 55°49′52″W / 47.0762°N 55.8310°W

Fortune Head GSSP, Newfoundland
Delegates from the Ichnia 2012 conference inspect the Global Boundary Stratotype Section and Point (GSSP) for the Ediacaran-Cambrian boundary at Fortune Head Ecological Reserve, Newfoundland, Canada. The boundary is defined on the appearance of the complex, vertical trace fossil Treptichnus (formerly Phycodes) pedum.

Type locality

The type locality (GSSP) of the Terreneuvian is in Fortune Head, at the northern edge of the Burin Peninsula, Newfoundland, Canada (47°04′34″N 55°49′52″W / 47.0762°N 55.8310°W). The outcrops show a carbonate-siliciclastic succession which is mapped as the Chapel Island Formation. The formation is divided into the following members that are composed of peritidal sandstones and shales (Member 1), muddy deltaic and shelf sandstones and mudstones (Member 2A), laminated siltstones (Member 2B and 3) and mudstones and limestones of the inner shelf (Member 4). The Precambrian-Cambrian boundary lies 2.4 m above the base of the second member, which is the lowest occurrence of Treptichnus pedum. The traces can be seen on the lower surface of the sandstone layers. The first calcareous shelled skeletal fossils (Ladatheca cylindrica) are 400 m above the boundary. The first trilobites appear 1400 m above the boundary, which corresponds to the beginning of the Branchian Series.[5]

References

  1. ^ a b Landing, E., Peng, S., Babcock, L. E., Geyer, G., & Moczydlowska-Vidal, M. (2007). Global standard names for the lowermost Cambrian series and stage. Episodes, 30(4), 287.
  2. ^ a b PENG, S.C. & BABCOCK, L.E. 2011. Continuing progress on chronostratigraphic subdivision of the Cambrian System. Bulletin of Geosciences 86(3), 391–396 (1 figure). Czech Geological Survey, Prague. ISSN 1214-1119.
  3. ^ http://www.stratigraphy.org/column.php?id=Chart/Time%20Scale
  4. ^ Li, G. "The Fad of Watsonella Crosbyi". Retrieved 10 November 2012.
  5. ^ Brasier, Martin; John Cowie; Michael Taylor (1994). "Decision on the Precambrian-Cambrian boundary stratotype" (PDF). Episodes. 17 (1–2): 95–100. Retrieved 14 September 2012.

See also

Barskovia

Barskovia is a torted conical shell known from earliest Cambrian small skeletal fossils, interpreted as a helcionelloid.

Cambrian Series 2

Cambrian Series 2 is the unnamed 2nd series of the Cambrian. It lies above the Terreneuvian series and below the Miaolingian. Series 2 has not been formally defined by the International Commission on Stratigraphy, lacking a precise lower boundary and subdivision into stages. The proposed lower boundary is the first appearance of trilobites which is estimated to be around 521 million years ago.

Cambrian Stage 2

Stage 2 of the Cambrian is the unnamed upper stage of the Terreneuvian series. It lies atop the Fortunian and below Stage 3 of the Cambrian. It is commonly referred to as the Tommotian, after the Cambrian stratigraphy of Siberia. Neither the upper nor lower boundary has yet been defined by the International Commission on Stratigraphy.

The preferred definitions for the lower boundary are the first appearance of the molluscs Watsonella crosbyi or Aldanella attleborensis around 529 million years ago. The proposed upper boundary might be the first appearance of trilobites around 521 million years ago.Possible candidates for a GSSP include the first appearance of Watsonella crosbyi in the Zhujiaqing Formation in Yunnan, China or the Pestrotsvet Formation near the Aldan River on the Siberian Platform.

Cambrian Stage 3

Cambrian Stage 3 is the still unnamed third stage of the Cambrian. It succeeds Cambrian Stage 2 and precedes Cambrian Stage 4, although neither its base nor top have been formally defined. The plan is for its lower boundary to correspond approximately to the first appearance of trilobites, about 521 million years ago, though the globally asynchronous appearance of trilobites warrants the use of a separate, globally synchronous marker to define the base. The upper boundary and beginning of Cambrian Stage 4 is informally defined as the first appearance of the trilobite genera Olenellus or Redlichia around 514 million years ago.

Chordate

A chordate () is an animal of the phylum Chordata ([kɔrˈdata]). During some period of their life cycle, chordates possess a notochord, a dorsal nerve cord, pharyngeal slits, an endostyle, and a post-anal tail: these five anatomical features define this phylum. Chordates are also bilaterally symmetric; and have a coelom, metameric segmentation, and a circulatory system.

The Chordata and Ambulacraria together form the superphylum Deuterostomia. Chordates are divided into three subphyla: Vertebrata (fish, amphibians, reptiles, birds, and mammals); Tunicata or Urochordata (sea squirts, salps); and Cephalochordata (which includes lancelets). There are also extinct taxa such as the Vetulicolia. Hemichordata (which includes the acorn worms) has been presented as a fourth chordate subphylum, but now is treated as a separate phylum: hemichordates and Echinodermata form the Ambulacraria, the sister phylum of the Chordates. Of the more than 65,000 living species of chordates, about half are bony fish that are members of the superclass Pisces, class Osteichthyes.

Chordate fossils have been found from as early as the Cambrian explosion, 541 million years ago. Cladistically (phylogenetically), vertebrates – chordates with the notochord replaced by a vertebral column during development – are considered to be a subgroup of the clade Craniata, which consists of chordates with a skull. The Craniata and Tunicata compose the clade Olfactores. (See diagram under Phylogeny.)

Eolympia

Eolympia (meaning "dawn (Greek word ‘eos’) + Olympic games") is interpreted as an extinct monospecific genus of sea anemone which existed in what is now Ningqiang, Shaanxi Province, China during the lower Cambrian period (Fortunian Stage of the Terreneuvian Series - the lower unit of the Lower Cambrian). Its fossils have been recovered from the Kuanchuanpu Formation. The pedicle (after which E. pediculata is named) is long, suggesting the animal engaged in sexual intercourse, though marked perforations imply that reproduction by transverse fission was also quite likely as a more primitive backup.The fossil may alternatively represent a scalidophoran worm.

Fallotaspidoidea

The ”Fallotaspidoidea” are a superfamily of trilobites, a group of extinct marine arthropods. It lived during the Lower Cambrian (Atdabanian) and species occurred on all paleocontinents except for the Gondwana heartland (currently Latin America, most of Africa, Australia, Antarctica, India and China). A member of this group, Profallotaspis jakutensis, has long been the earliest known trilobite, but recently the redlichiid Lemdadella has been claimed as occurring even earlier.

Fortunian

The Fortunian stage marks the beginning of the Phanerozoic eon, the Paleozoic era, and the Cambrian period. It is the first of the two stages of the Terreneuvian series. Its base is defined as the first appearance of the trace fossil Treptichnus pedum 541 million years ago. The top of the Fortunian which is the base of the Stage 2 of the Cambrian has not been formally defined yet, but will correspond to the appearance of an Archeocyatha species or "Small shelly fossils" approximately 529 million years ago.The name Fortunian is derived from a part of the Burin Peninsula, the town of Fortune near the GSSP and Fortune Bay.

Franco-Newfoundlander

Franco-Newfoundlanders, also known as Franco-Terreneuvians in English or Franco-Terreneuviens in French, are francophone and/or French Canadian residents of the Canadian province of Newfoundland and Labrador. The name Franco-Terreneuvian derives from Terre-Neuve, the French name of Newfoundland.

The Franco-Newfoundlander community is most prominently associated with the Port au Port area near Stephenville, in communities such as Trois-Cailloux, Cap-Saint-Georges, La Grand'Terre, L'Anse-aux-Canards and Maisons-d'Hiver. This region is unique as the only area in the province that is officially designated by provincial law as a bilingual district. However, francophone communities are also present throughout the province, particularly in St. John's, Labrador City and Happy Valley-Goose Bay.Newfoundland and Labrador's francophone community and its culture derive from a unique mix of influences and immigrants from Quebec, Acadia, St. Pierre and Miquelon, Brittany and the Basque Country, much of it predating Newfoundland's admission as a Canadian province in 1949. Some aspects of the community's unique culture, however, have been lost or threatened as the community became more closely integrated into the mainstream of French Canadian culture and society after 1949.

Holmiidae

Holmiidae is a family of trilobites, that lived during the Lower Cambrian (Atdabanian). The Holmiidae is a diverse family of eight genera containing at least 17 species. It includes some of the earliest trilobites of Baltica. Holmiidae occur throughout Baltica (Scandinavia and the eastern seaboard of the Baltic Sea) and Western Laurentia (in the Great Basin of the USA and northwestern Canada), and also in Morocco.

Judomioidea

The Judomioidea are a superfamily of trilobites, a group of extinct marine arthropods. Its species lived during the Lower Cambrian (Atdabanian).

Mickwitzia

Mickwitziids are a Cambrian group of shelly fossils with originally phosphatic valves, belonging to the Brachiopod stem group, and exemplified by the genus Mickwitzia – the other genera are Heliomedusa (a possible junior synonym of Mickwitzia?) and Setatella.

The family Mickwitziidae is conceivably paraphyletic with respect to certain crown-group brachiopods.

Naraoiidae

Naraoiidae is a family, of extinct, soft-shelled trilobite-like arthropods, that belongs to the order Nectaspida. Species included in the Naraoiidae are known from the second half of the Lower Cambrian to the end of the Upper Silurian. The total number of collection sites is limited and distributed over a vast period of time: Maotianshan Shale and Balang Formation (China), Burgess Shale and Bertie Formation (Canada), the Šárka Formation (Czech Republic), Emu Bay Shale (Australia), Idaho and Utah (USA). This is probably due to the rare occurrence of the right circumstances for soft tissue preservation, needed for these non-calcified exoskeletons.

Redlichiida

Redlichiida is an order of trilobites, a group of extinct marine arthropods. Species assigned to the order Redlichiida are among the first trilobites to appear in the fossil record, about halfway during the Lower Cambrian. Due to the difficulty to relate sediments in different areas, there remains some discussion, but among the earliest are Fallotaspis (suborder Olenellina), and Lemdadella (suborder Redlichiina), both belonging to this order. The first representatives of the orders Corynexochida and Ptychopariida also appear very early on and may prove to be even earlier than any redlichiid species. In terms of anatomical comparison, the earliest redlichiid species are probably ancestral to all other trilobite orders and share many primitive characters. The last redlichiid trilobites died out before the end of the Middle Cambrian.

Sandbian

The Sandbian is the first stage of the Upper Ordovician. It follows the Darriwilian and is succeeded by the Katian. Its lower boundary is defined as the first appearance datum of the graptolite species Nemagraptus gracilis around 458.4 million years ago. The Sandbian lasted for about 5.4 million years until the beginning of the Katian around 453 million years ago.

Tommotiid

Tommotiids are Cambrian (Terreneuvian) shelly fossils thought to belong to the Brachiopod + Phoronid lineage (Brachiozoa).The majority of tommotiids are mineralised with calcium phosphate rather than calcium carbonate. although silicified examples hint that some species bore carbonate or carbonaceous sclerites.Micrina and Paterimitra possess bivalved shells in their larval phases, which preserve characters that might position them in the Linguliformea and Rhynchonelliformea stem lineages respectively. This would indicate that the brachiopod shell represents the retention of a larval character.For a long part of their history, the tommotiids were only known from disarticulated shells - a complete organism had not been found. The 2008 discovery of Eccentrotheca offered the first insight into a complete organism, and permitted a reconstruction of the animal as a sessile, tube-like animal made up of a spiral of overlapping plates.Articulated specimens of Paterimitra, discovered a year later, suggest a similar form and lifestyle - it is possible that many tommotiids need redescribing as sessile tube-dwellers.These discoveries have produced an alternative model for the origin of the brachiopods; it suggested that they evolved by the reduction of sessile tube-like organisms, until only two shells were left. This contrasts with the brachiopod fold hypothesis which suggests that they formed by the folding of a halkieriid-like organism.

Vertebrate

Vertebrates comprise all species of animals within the subphylum Vertebrata (chordates with backbones). Vertebrates represent the overwhelming majority of the phylum Chordata, with currently about 69,963 species described. Vertebrates include such groups as the following:

jawless fishes

jawed vertebrates, which include the cartilaginous fishes (sharks, rays, and ratfish)

tetrapods, which include amphibians, reptiles, birds and mammals

bony fishesExtant vertebrates range in size from the frog species Paedophryne amauensis, at as little as 7.7 mm (0.30 in), to the blue whale, at up to 33 m (108 ft). Vertebrates make up less than five percent of all described animal species; the rest are invertebrates, which lack vertebral columns.

The vertebrates traditionally include the hagfish, which do not have proper vertebrae due to their loss in evolution, though their closest living relatives, the lampreys, do. Hagfish do, however, possess a cranium. For this reason, the vertebrate subphylum is sometimes referred to as "Craniata" when discussing morphology.

Molecular analysis since 1992 has suggested that hagfish are most closely related to lampreys, and so also are vertebrates in a monophyletic sense. Others consider them a sister group of vertebrates in the common taxon of craniata.

Watsonella

Watsonella is a genus of 'mollusc' known from early (Terreneuvian) Cambrian strata.

The genus is closely related to Anabarella, with which it bears many morphological similarities, including a laminar internal shell microstructure said to connect it with the early bivalves Fordilla and Pojetaia.

Xenusion

Xenusion auerswaldae is an early arthropod/onychophore known from two specimens found in glacial debris in Germany. They probably originated in the Kalmarsund Sandstone of Southern Sweden (Jaeger and Martinsson 1966), which was deposited in the Lower Cambrian (Upper Tommotian–Lower Atdabanian; Stages 2→3). The specimens are not especially well preserved. The older specimen is 10 cm or so in length with a narrow, weakly segmented body. A depression runs up the bottom on all but the rearmost segments. There is a slightly bulbous tail, and each segment beyond that seems to have a single pair of tapering annulated legs similar to the modern onychophore, but without claws. Nine segments are present. There is a spine on each body bump and faint transverse parallel striations on the annulations on the legs. The legs of what is possibly the foremost segments are either missing or not preserved. The head is believed to be missing or is poorly preserved. If Xenusion is an arthropod/onychophore, it is one of the oldest currently known fossils of a mobile, modern animal.

It's been said to have a long narrow proboscis, but this is probably a preservational artefact.Xenusion has been reinterpreted as an Ediacaran frond animal by Tarlo, and a drawing of that interpretation has been presented by McMenamin. Assuming that the creature is actually a lobopodian, the original specimen would appear to be part of an animal about 20 cm in length.

In a photograph presented in The Treatise on Invertebrate Paleontology Volume O, the organism's appearance seems to support the original interpretation more. Further studies of Xenusiid close the possibility of a Rangeomorphy affinity.

Cenozoic era
(present–66.0 Mya)
Mesozoic era
(66.0–251.902 Mya)
Paleozoic era
(251.902–541.0 Mya)
Proterozoic eon
(541.0 Mya–2.5 Gya)
Archean eon (2.5–4 Gya)
Hadean eon (4–4.6 Gya)

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