| Redlichia chinensis | |
|---|---|
 | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | † Trilobita |
| Order: | † Redlichiida |
| Family: | † Redlichiidae |
| Genus: | † Redlichia |
| Species: | †R. chinensis |
| Binomial name | |
| †Redlichia chinensis (Walcott, 1905) | |
Redlichia chinensis is an extinct species of trilobite that existed from 526 million years ago to 513 million years ago in the early Cambrian period (4th stage). [1]
The species is a nektobenthic deposit feeder.
R. chinensis was discovered by Chang in 1966 in the Balang formation, China. 19 fossils have been discovered. [2] [3]
R. chinensis has a wide cephalon with a border and the glaella tapers forwards. The hypostoma has been pushed through from the underside and the genal spines are not at the occipital edge. The thorax narrows to a small pygidium and the pleurae terminate in short spines. R. chinensis is 7.5 centimeters long. [4]
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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 252 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.
Paradoxides is a genus of large to very large trilobite found throughout the world during the Middle Cambrian period. One record-breaking specimen of Paradoxides davidis, described by John William Salter in 1863, is 37 cm (15 in). The cephalon was semicircular with free cheeks ending in long, narrow, recurved spines. Eyes were crescent shaped providing an almost 360° view, but only in the horizontal plane. Its elongate thorax was composed of 19-21 segments and adorned with longish, recurved pleural spines. Its pygidium was comparatively small. Paradoxides is a characteristic Middle-Cambrian trilobite of the 'Atlantic' (Avalonian) fauna. Avalonian rocks were deposited near a small continent called Avalonia in the Paleozoic Iapetus Ocean. Avalonian beds are now in a narrow strip along the East Coast of North America, and in Europe.
Olenellina is a suborder of the order Redlichiida of trilobites that occurs about halfway during the Lower Cambrian, at the start of the stage called the Atdabanian. The earliest trilobites in the fossil record are arguably Olenellina, although the earliest Redlichiina and Eodiscina follow quickly. The suborder died out when the Lower passed into the Middle Cambrian, at the end of the stage called Toyonian. A feature uniting the Olenellina is the lack of rupture lines in the headshield, which in other trilobites assist the periodic moulting, associated with arthropod growth. Some derived trilobites have lost facial sutures again, but all of these are blind, while all Olenellina have eyes.
Redlichia is a genus of redlichiid trilobite in the family Redlichiidae, with large to very large species. Fossils of various species are found in Lower Cambrian (Toyonian)-aged marine strata from China, Korea, Pakistan, the Himalayas, Iran, Spain, southern Siberia, and Antarctica, and from Middle Cambrian (Ordian)-aged marine strata of Australia.
The Emu Bay Shale is a geological formation in Emu Bay, South Australia, containing a major Konservat-Lagerstätte. It is one of two in the world containing Redlichiidan trilobites. The Emu Bay Shale is dated as Cambrian Series 2, Stage 4, correlated with the upper Botomian Stage of the Lower Cambrian.
Anomalocaris is a genus of extinct invertebrates that lived during the Cambrian Period. The fossils, known from the Burgess Shale fauna in Canada, Emu Bay Shale of Australia, and Chengjiang biota in China, represent "the largest Cambrian animal", measuring about half a meter in length. Originally classified as crustaceans, they are now regarded as a distinct group of early-diverging stem-group arthropods, for which the order Radiodonta and subphylum Dinocaridida were created.
Ampyx is an Ordovician-Silurian genus of Asaphid trilobites of the family Raphiophoridae. Species of Ampyx are characterized by three extended spines on the head-shield, one spine derived from each free cheek, and one spine emanating from the glabellum. Species include Ampyx linleyensis.
Resserops is an extinct genus from a well-known class of fossil marine arthropods, the trilobites. It lived during the middle of the Atdabanian or the early part of the Botomian stage, which lasted from approximately 524 to 518.5 million years ago. This faunal stage was part of the Cambrian Period. It has been found in Spain and southern Morocco. It can be recognised by the sabre-like spines of the headshield that are a smooth continuation of the frontal edge, and the enlarged spines on the 9th segment of the thorax.
Meteoraspis is an extinct genus of ptychopariid trilobites of the family Tricrepicephalidae. The various species lived from 501 to 490 million years ago during the Dresbachian faunal stage of the late Cambrian Period. Fossils of Meteoraspis are characteristic of Late Cambrian strata in North America, though they are found in Late Cambrian strata elsewhere in the world, such as M. nevensis from Victoria Land, Antarctica.
A number of assemblages bear fossil assemblages similar in character to that of the Burgess Shale. While many are also preserved in a similar fashion to the Burgess Shale, the term "Burgess Shale-type fauna" covers assemblages based on taxonomic criteria only.
The Cambrian explosion, Cambrian radiation,Cambrian diversification, or the Biological Big Bang refers to an interval of time approximately 538.8 million years ago in the Cambrian Period when practically all major animal phyla started appearing in the fossil record. It lasted for about 13 – 25 million years and resulted in the divergence of most modern metazoan phyla. The event was accompanied by major diversification in other groups of organisms as well.
Kuamaia is an extinct genus of artiopodan in the phylum Arthropoda. Fossils of the type species K. lata were discovered in the Chengjiang biota. The other species in the genus,K. muricata has also been identified there, but neither species has been found elsewhere.
Eoredlichia is an extinct genus of trilobite of average to large size. It lived during the early Cambrian in the Chengjiang fauna of Yunnan, China, and in Australia and Thailand. Eoredlichia is compounded of the Greek ἠώς and Redlichia, a later but related genus, so it means "early Redlichia". The species epithet intermedia means intermediate, indicating it is morphologically intermediate between other species. Eofallotaspis gives rise to Lemdadella, and thence to Eoredlichia and the other Redlichiidae.
Lochmanolenellus is an extinct genus of trilobites, fossil marine arthropods, with one small species, L. mexicana. It lived during the Botomian stage (Olenellus-zone), 522–513 million years ago, in the South-West of the former continent of Laurentia, in what are today Mexico, and the South-Western United States.
Cambrian Stage 4 is the still unnamed fourth stage of the Cambrian and the upper stage of Cambrian Series 2. It follows Cambrian Stage 3 and lies below the Wuliuan. The lower boundary has not been formally defined by the International Commission on Stratigraphy. One proposal is the first appearance of two trilobite genera, Olenellus or Redlichia. Another proposal is the first appearance of the trilobite species Arthricocephalus chauveaui. Both proposals will set the lower boundary close to 514 million years ago. The upper boundary corresponds to the beginning of the Wuliuan.
Angelina Salter, 1859, is a genus of ptychopariid trilobite belonging to the Family Olenidae, Suborder olenina. It lived during the Tremadocian Stage, lowermost of the two standard worldwide divisions forming the Lower Ordovician Series and lowest of the seven stages within the Ordovician System. It encompasses all rocks formed during Tremadocian times, which spanned the interval between 485.4 million and 477.7 million years ago. Fossilized remains of Angelina are known from Wales, Central and South America. It differs from most other Triarthrinae in being larger, with a relatively narrow glabella, the occipital ring poorly defined, and lateral glabellar furrows relatively obscure. Eyes are placed midlength that of the cephalon and the facial sutures converge on the front border at the midline. Species also have long genal spines.
Genevievella is a genus of trilobites with a short inverted egg-shaped outline, a wide headshield, small eyes, and long genal spines. The backrim of the headshield is inflated and overhangs the first of the 9 thorax segments. The 8th thorax segment from the front bears a backward directed spine that reaches beyond the back end of the exoskeleton. It has an almost oval tailshield with 5 pairs of pleural furrows. It lived during the Upper Cambrian in what are today Canada and the United States.
Tricrepicephalus is an extinct genus of ptychopariid trilobites of the family Tricrepicephalidae with species of average size. Its species lived from 501 to 490 million years ago during the Dresbachian faunal stage of the late Cambrian Period. Fossils of Tricrepicephalus are widespread in Late Cambrian deposits in North America, but is also known from one location in South-America. Tricrepicephalus has an inverted egg-shaped exoskeleton, with three characteristic pits in the fold that parallels the margin of the headshield just in front of the central raised area. The articulating middle part of the body has 12 segments and the tailshield carries two long, tubular, curved pygidial spines that are reminiscent of earwig's pincers that rise backwards from the plain of the body at approximately 30°.
Serrodiscus Richter and Richter 1941. is a genus of Eodiscinid trilobite belonging to the family Weymouthiidae Kobayashi T. (1943), Order Agnostida. It lived during the late Lower Cambrian, with remains found in Canada, China (Gansu), The United Kingdom (England), Germany (Silesia), Poland, the Russian Federation, and the United States. It is named for the spines on the ventral side of the pygidium, which give it a serrated impression.
Erratus is an extinct genus of marine arthropod from the Cambrian of China. Its type and only species is Erratus sperare. Erratus is likely one of the most basal known arthropods, and its discovery has helped scientists understand the early evolution of arthropod trunk appendages. Some of the stem-arthropods like radiodonts did not have legs, instead they had flap like appendages that helped them swim. Erratus on the other hand had not only flaps but also a set of primitive legs. It also supported the theory that the gills of aquatic arthropods probably evolved into the wings and lungs of terrestrial arthropods later in the Paleozoic.