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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. Description Most redlichiids are rather flat (or have low dorso–ventral convexity) and their exoskeleton typically has an oval ou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trilobite
Trilobites (; meaning "three-lobed entities") are extinction, extinct marine arthropods that form the class (biology), class Trilobita. One of the earliest groups of arthropods to appear in the fossil record, trilobites were among the most successful of all early animals, existing in oceans for almost 270million years, with over 22,000 species having been described. Because trilobites had wide diversity and an easily fossilized mineralised exoskeleton made of calcite, they left an extensive fossil record. The study of their fossils has facilitated important contributions to biostratigraphy, paleontology, evolution, evolutionary biology, and plate tectonics. Trilobites are placed within the clade Artiopoda, which includes many organisms that are morphologically similar to trilobites, but are largely unmineralised. The relationship of Artiopoda to other arthropods is uncertain. Trilobites evolved into many ecological niches; some moved over the seabed as predators, scavengers, or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Emu Bay Shales
The Emu Bay Shale is a geological formation in Emu Bay, South Australia, containing a major Konservat-Lagerstätte (fossil beds with soft tissue preservation). 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. Its mode of preservation is the same as the Burgess shale, but the larger grain size of the Emu Bay rock means that the quality of preservation is lower. More than 50 species of trilobites, non-biomineralized arthropods (including megacheirans, nektaspids, and hymenocarines), radiodonts, palaeoscolecids, a lobopodian, a polychaete, vetulicolians, nectocaridids, hyoliths, brachiopods, sponges, chancelloriids, several problematica and a chelicerate are known from the Emu Bay Shale. Description The Emu Bay Shale of Kangaroo Island, South Australia, is Australia's only known Burgess-Shale-type Konservat-Lagerstätte, and includes f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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. Description Most redlichiids are rather flat (or have low dorso–ventral convexity) and their exoskeleton typically has an oval ou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Redlichiina
Redlichiina is a suborder of the order Redlichiida of Trilobites. The suborder contains three superfamilies: Emuelloidea, Redlichioidea and Paradoxidoidea. These trilobites are some of the oldest trilobites known. They originated at the beginning of the Cambrian The Cambrian ( ) is the first geological period of the Paleozoic Era, and the Phanerozoic Eon. The Cambrian lasted 51.95 million years from the end of the preceding Ediacaran period 538.8 Ma (million years ago) to the beginning of the Ordov ... Period and disappeared (possibly by evolving into members of the Ptychopariida order) at the end of the middle Cambrian. Physiology Cephalon: Opisthoparian facial sutures. Early forms tend to have tapering, conical glabella with furrows extending far backwards while later forms with glabella expanding forwards to inflated frontal lobe. The hypostome is conterminant (e.g., Redlichia) or natant (e.g., Dolerolenus). The rostral plate is narrower than in suborder ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lemdadella
''Lemdadella'' is an extinct genus of redlichiid trilobites that lived during the late Atdabanian stage, which lasted from 521 to 514 million years ago during the early part of the Cambrian Period. Distribution * ''Lemdadella'' sp. occurs in the Lower Cambrian of Morocco (Botomian, Ounein A bioherm, Lemdad 1 section, High Atlas) * ''Lemdadella linaresae'' was collected in the Lower Cambrian of Spain (Atdabanian, Pedroche Formation, Member 1, Puente de Hierro Section) * ''Lemdadella sp.'' was found in the Lower Cambrian of Antarctica (Toyonian, Shackleton Limestone; BC-BD collections) * ''Lemdadella antarcticae'' occurs in the Lower Cambrian of Antarctica (Atdabanian, Shackleton Limestone; BC-BD collections) Description Glabella gently tapered forward. At the midline, a ridge between the glabella and the border of the cephalon (a so-called plectrum) may be present. Crescent-shaped eye-ridges. Thorax not divided in prothorax and opisthothorax, no macropleural segment. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fallotaspis
''Fallotaspis'' is a genus of redlichiid trilobites found in Early Cambrian-aged strata of the United States and Morocco Morocco, officially the Kingdom of Morocco, is a country in the Maghreb region of North Africa. It has coastlines on the Mediterranean Sea to the north and the Atlantic Ocean to the west, and has land borders with Algeria to Algeria–Morocc .... Etymology The generic name, Fallotaspis, is a compound crassis word that honors Paul Fallot (1889-1960), a French paleontologist who researched Cambrian fossils in Spain, in combination with the Greek language, Greek word ἀσπίς, ''aspis'', meaning shield. Description As with most early trilobites, ''Fallotaspis'' has an almost flat exoskeleton, that is only thinly calcified, and has crescent-shaped eye ridges. As part of the Olenellina suborder, ''Fallotaspis'' lacks dorsal sutures. As part of the superfamily Fallotaspidoidea ''Fallotaspis'' can be distinguished from Olenelloidea, Judomioidea and N ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Olenellina
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. Olenellina are arguably the earliest trilobites in the fossil record as members of Redlichiina, although Ptychopariida and Eodiscina follow soon after. The suborder died out when the Lower Cambrian passed into the Middle Cambrian, at the end of the stage called Toyonian. A feature uniting the Olenellina is the lack of rupture lines (or Trilobite#Dorsal sutures, sutures) in the headshield, which in other trilobites assist the periodic moulting (or ecdysis), associated with arthropod growth. Some derived trilobites have lost facial sutures again (some Eodiscina, all Agnostina, and a few Phacopina), but all of these are blind, while all Olenellina have eyes. Taxonomy The suborder contains four superfamilies: Olenelloidea (with 3 families and 5 stemgroup genera), Judomioidea (with 1 family and 3 stemgroup genera), Nevad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Treatise On Invertebrate Paleontology
The ''Treatise on Invertebrate Paleontology,'' published from 1953–2007 by the Geological Society of America and the University of Kansas, then 2009–present by the University of Kansas Paleontological Institute, is a definitive multi-authored work of currently 55 volumes, written by more than 300 paleontologists, and covering every phylum, class, order, family, and genus of fossil and extant (still living) invertebrate animals. The prehistoric invertebrates are described as to their taxonomy, morphology, paleoecology, stratigraphic and paleogeographic range. However, taxa with no fossil record whatsoever have just a very brief listing. Publication of the decades-long ''Treatise on Invertebrate Paleontology'' is a work-in-progress; and therefore it is not yet complete: For example, there is no volume yet published regarding the post- Paleozoic era caenogastropods (a molluscan group including the whelk and periwinkle). Furthermore, when needed, previously published vol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypostome (trilobite)
The hypostome is the hard mouthpart of trilobites found on the ventral side of the cephalon (head). The hypostome can be classified into three types based on whether they are permanently attached to the rostrum or not and whether they are aligned to the anterior dorsal tip of the glabella. Morphology The center of the hypostome is an ovoid, typically convex part called the median body, often divided into an anterior lobe and a posterior lobe. Either side of the median body is a border with various extensions, including anterior and posterior wings, sometimes bearing knob-like processes. The hypostome is hollow, and encloses the mouthparts, the anterior digestive tract, and the bases of the antennae. Trilobite antennae pass through notches between the anterior and posterior wings, then forward. The anterior wings are designed to rest firmly against internal structures (ventral apodemes) on the glabella. Variation in trilobite hypostome morphology is crucial in modern discussi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cambrian
The Cambrian ( ) is the first geological period of the Paleozoic Era, and the Phanerozoic Eon. The Cambrian lasted 51.95 million years from the end of the preceding Ediacaran period 538.8 Ma (million years ago) to the beginning of the Ordovician Period 486.85 Ma. Most of the continents lay in the southern hemisphere surrounded by the vast Panthalassa Ocean. The assembly of Gondwana during the Ediacaran and early Cambrian led to the development of new convergent plate boundaries and continental-margin arc magmatism along its margins that helped drive up global temperatures. Laurentia lay across the equator, separated from Gondwana by the opening Iapetus Ocean. The Cambrian marked a profound change in life on Earth; prior to the Period, the majority of living organisms were small, unicellular and poorly preserved. Complex, multicellular organisms gradually became more common during the Ediacaran, but it was not until the Cambrian that fossil diversity seems to rapidly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Olenellus Chiefensis CRF
''Olenellus'' is an extinct genus of redlichiid trilobites, with species of average size (about long). It lived during the Botomian and Toyonian stages of the Lower Cambrian (''Olenellus''-zone), , in what is currently North America, part of the palaeocontinent Laurentia. Etymology ''Olenellus fowleri'' was named in honor of Ed Fowler''Olenellus'' means small ''Olenus'', after a genus belonging to the Ptychopariida, to which the type species ''O. thompsoni'' was originally assigned. The name Olenus refers to a mythological figure who was turned to stone by the gods. The names of the species have the following derivations. * ''agellus'' comes from the Latin word for field or hamlet. * ''chiefensis'' refers to the Chief Range, which includes the Ruin Wash section, that holds the last of the Olenellina. * ''fowleri'' was named in honor of Ed Fowler, whose quarrying skills exposed the type locality of this species. * ''getzi'' is called afteNoah L. Getz on whose Lancaster ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
