| Saukiella Temporal range: | |
|---|---|
 | |
| S. pepinensis from Wisconsin | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | † Trilobita |
| Order: | † Asaphida |
| Family: | † Saukiidae |
| Genus: | † Saukiella Ulrich & Resser, 1933 |
| Species | |
| |
Saukiella is a genus of trilobites of the Saukiidae family.
These fast-moving low-level epifaunal deposit feeders lived in the Cambrian and Ordovician periods, from 498.5 to 478.6 Ma. [1] [2]
Fossils of species within this genus have been found in the Ordovician sediments of Russia and in the Cambrian sediments of Canada, China, Kazakhstan and United States. [1]
The Ordovician is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period 485.4 million years ago (Mya) to the start of the Silurian Period 443.8 Mya.
The Silurian is a geologic period and system spanning 24.6 million years from the end of the Ordovician Period, at 443.8 million years ago (Mya), to the beginning of the Devonian Period, 419.2 Mya. The Silurian is the shortest period of the Paleozoic Era. As with other geologic periods, the rock beds that define the period's start and end are well identified, but the exact dates are uncertain by a few million years. The base of the Silurian is set at a series of major Ordovician–Silurian extinction events when up to 60% of marine genera were wiped out.
Trilobites are a group of 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 252 million years ago. Trilobites were among the most successful of all early animals, existing in oceans for almost 270 million years, with over 20,000 species having been described.
Acritarchs are organic microfossils, known from approximately 1800 million years ago to the present. The classification is a catch all term used to refer to any organic microfossils that cannot be assigned to other groups. Their diversity reflects major ecological events such as the appearance of predation and the Cambrian explosion.
A trace fossil, also ichnofossil, is a fossil record of biological activity but not the preserved remains of the plant or animal itself. Trace fossils contrast with body fossils, which are the fossilized remains of parts of organisms' bodies, usually altered by later chemical activity or mineralization. The study of such trace fossils is ichnology and is the work of ichnologists.
The Rostroconchia is a class of extinct molluscs dating from the early Cambrian to the Late Permian. They were initially thought to be bivalves, but were later given their own class. They have a single shell in their larval stage, and the adult typically has a single, pseudo-bivalved shell enclosing the mantle and muscular foot. The anterior part of the shell probably pointed downward and had a gap from which the foot could probably emerge. Rostroconchs probably lived a sedentary semi-infaunal lifestyle. There were probably more than 1,000 species of members of this class.
The Tremadocian is the lowest stage of Ordovician. Together with the later Floian Stage it forms the Lower Ordovician Epoch. The Tremadocian lasted from 485.4 to 477.7 million years ago. The base of the Tremadocian is defined as the first appearance of the conodont species Iapetognathus fluctivagus at the Global Boundary Stratotype Section and Point (GSSP) section on Newfoundland.
Dikelocephalus is a genus of very large trilobites of up to 50 cm (20 in) long, that lived during the last 3 million years of the Cambrian (Sunwaptan). Their fossils are commonly found as disarticulated sclerites, in the upper Mississippi Valley and in Canada (Alberta). The exoskeleton is rounded anteriorly, with the thorax and sides of the tailshield slightly tapering to about ⅔× of the width across the base of the spines at the back of the headshield. At the side corners of the pygidium there may be triangular or hooked spines, pointing backwards, while between the spines the posterior margin is at a 30-75° angle with the lateral margin, gently convex or nearly straight. If pygidial spines are lacking, the margin is gradually rounded. The thorax has 12 segments.
The Ordovician radiation, or the Great Ordovician Biodiversification Event (GOBE), was an evolutionary radiation of animal life throughout the Ordovician period, 40 million years after the Cambrian explosion, whereby the distinctive Cambrian fauna fizzled out to be replaced with a Paleozoic fauna rich in suspension feeder and pelagic animals.
Clarkoceras is a genus of breviconic ellesmerocerid cephalopods, one of only two genera known to have crossed from the Late Cambrian, Trempealeauan, into the Early Ordovician, Gasconadian. ; the other being Ectenolites.
The Kirengellids are a group of problematic Cambrian fossil shells of marine organisms. The shells bear a number of paired muscle scars on the inner surface of the valve.
Salterella is an enigmatic Cambrian genus with a small, conical, calcareous shell that appears to be septate, but is rather filled with stratified laminar deposits. The shell contains grains of sediment, which are obtained selectively by a manner also observed in foramanifera. The genus was established by Elkanah Billings in 1861, and was named after the English palaeontologist John William Salter.
The Upper and Lower Fezouata Formations of Morocco are Burgess shale-type deposits dating to the Early Ordovician, filling an important preservational window between the common Cambrian Lagerstätten and the Late Ordovician Soom Shale. Found fossilized fauna were numerous organisms previously thought to have died out after the mid-Cambrian.
The Hebridean Terrane is one of the terranes that form part of the Caledonian orogenic belt in northwest Scotland. Its boundary with the neighbouring Northern Highland Terrane is formed by the Moine Thrust Belt. The basement is formed by Archaean and Paleoproterozoic gneisses of the Lewisian complex, unconformably overlain by the Neoproterozoic Torridonian sediments, which in turn are unconformably overlain by a sequence of Cambro–Ordovician sediments. It formed part of the Laurentian foreland during the Caledonian continental collision.
The geology of the Isle of Skye in Scotland is highly varied and the island's landscape reflects changes in the underlying nature of the rocks. A wide range of rock types are exposed on the island, sedimentary, metamorphic and igneous, ranging in age from the Archaean through to the Quaternary.
Saukiidae is a family of trilobites of the Asaphida order.
The Deadwood Formation is a geologic formation of the Williston Basin and Western Canada Sedimentary Basin. It is present in parts of North and South Dakota and Montana in the United States, and in parts of Alberta, Saskatchewan, and southwestern corner of Manitoba in Canada. It is of Late Cambrian to Early Ordovician age and was named for exposures in Whitewood Creek near Deadwood, South Dakota. It is a significant aquifer in some areas, and its conglomerates yielded significant quantities of gold in the Black Hills of South Dakota.
The Famatinian orogeny is an orogeny that predates the rise of the Andes and that took place in what is now western South America during the Paleozoic, leading to the formation of the Famatinian orogen also known as the Famatinian belt. The Famatinian orogeny lasted from the Late Cambrian to at least the Late Devonian and possibly the Early Carboniferous, with orogenic activity peaking about 490 to 460 million years ago. The orogeny involved metamorphism and deformation in the crust and the eruption and intrusion of magma along a Famatinian magmatic arc that formed a chain of volcanoes. The igneous rocks of the Famatinian magmatic arc are of calc-alkaline character and include gabbros, tonalites and granodiorites. The youngest igneous rocks of the arc are granites.
The Timanide Orogen is a pre-Uralian orogen that formed in northeastern Baltica during the Neoproterozoic in the Timanide orogeny. The orogen is about 3000 km long. Its extreme points include the southern Urals in the south and the Polar Urals, the Kanin and Varanger peninsulas in the north. The Timan Ridge is the type area of the orogen. To the west, at the Varanger Peninsula, the north-west oriented Timanide Orogen is truncated by the younger Scandinavian Caledonide Orogen that has an oblique disposition. The northeastern parts of the orogen are made up of volcanic and sedimentary rocks, granitoids and few ophiolites. In contrast the southwestern part of the orogen is made up mostly of sedimentary rocks. I and A type granitoids and volcanic rocks are common in the orogen.
The geology of Jordan includes thick sedimentary sequences of sandstone, marl and evaporites atop ancient Precambrian crystalline igneous and metamorphic basement rock.
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