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Eocrinoidea
The Eocrinoidea are an extinct class of echinoderms that lived between the Early Cambrian and Late Silurian periods. They are the earliest known group of stalked, arm-bearing echinoderms, and were the most common echinoderms during the Cambrian. Eocrinoids were a paraphyletic group that may have been ancestral to six other classes: Rhombifera, Diploporita, Coronoidea, Blastoidea, Parablastoidea, and Paracrinoidea. They may also be the progenitors of the cystoids, who are believed to be ancestral to modern crinoids. The earliest genera had a short holdfast and irregularly structured plates. Later forms had a fully developed stalk with regular rows of plates. They were benthic suspension feeders, with five ambulacra on the upper surface, surrounding the mouth and extending into a number of narrow arms. An unusual Ordovician form was the conical '' Bolboporites'' with its single brachiole.Rozhnov, S.V. and Kushlina, V.B. 1994. Interpretation of new data on ''Bolboporites'' Pande ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhombifera
The Eocrinoidea are an extinct class of echinoderms that lived between the Early Cambrian and Late Silurian periods. They are the earliest known group of stalked, arm-bearing echinoderms, and were the most common echinoderms during the Cambrian. Eocrinoids were a paraphyletic group that may have been ancestral to six other classes: Rhombifera, Diploporita, Coronoidea, Blastoidea, Parablastoidea, and Paracrinoidea. They may also be the progenitors of the cystoids, who are believed to be ancestral to modern crinoids. The earliest genera had a short holdfast and irregularly structured plates. Later forms had a fully developed stalk with regular rows of plates. They were benthic suspension feeders, with five ambulacra on the upper surface, surrounding the mouth and extending into a number of narrow arms. An unusual Ordovician form was the conical '' Bolboporites'' with its single brachiole.Rozhnov, S.V. and Kushlina, V.B. 1994. Interpretation of new data on ''Bolboporites'' Pan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Echinodermata Orders
This List of echinoderm orders concerns the various classes and orders into which taxonomists categorize the roughly 7000 extant species as well as the extinct species of the exclusively marine phylum Echinodermata. Subphylum Crinozoa Class Crinoidea * Subclass Articulata (540 species) ** Order Bourgueticrinida ** Order Comatulida ** Order Cyrtocrinida ** Order Hyocrinida ** Order Isocrinida ** Order Millericrinida * Subclass †Flexibilia * Subclass † Camerata * Subclass †Disparida Image:Comaster schlegelii.JPG, '' Comaster schlegelii'' (Comatulida) Image:Holopus 2.jpg, ''Holopus sp.'' (Cyrtocrinida) Image:Encrinus liliiformis 4.JPG, '' Encrinus liliiformis'' ( Encrinida) Image:Calamocrinus diomedæ (Plate XXVIII) BHL4232451.jpg, '' Calamocrinus diomedae'' ( Hyocrinida) Image:Proisocrinus ruberrimus.jpg, '' Proisocrinus ruberrimus'' (Isocrinida) Image:Liliocrinus polydactylus MHNT.jpg, '' Liliocrinus polydactylus'' (Millericrinida) Class Paracrinoidea † N ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crinoids
Crinoids are marine animals that make up the class Crinoidea. Crinoids that are attached to the sea bottom by a stalk in their adult form are commonly called sea lilies, while the unstalked forms are called feather stars or comatulids, which are members of the largest crinoid order, Comatulida. Crinoids are echinoderms in the phylum Echinodermata, which also includes the starfish, brittle stars, sea urchins and sea cucumbers. They live in both shallow water and in depths as great as . Adult crinoids are characterised by having the mouth located on the upper surface. This is surrounded by feeding arms, and is linked to a U-shaped gut, with the anus being located on the oral disc near the mouth. Although the basic echinoderm pattern of fivefold symmetry can be recognised, in most crinoids the five arms are subdivided into ten or more. These have feathery pinnules and are spread wide to gather planktonic particles from the water. At some stage in their lives, most crinoids have a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Echinoderm
An echinoderm () is any member of the phylum Echinodermata (). The adults are recognisable by their (usually five-point) radial symmetry, and include starfish, brittle stars, sea urchins, sand dollars, and sea cucumbers, as well as the sea lilies or "stone lilies". Adult echinoderms are found on the sea bed at every ocean depth, from the intertidal zone to the abyssal zone. The phylum contains about 7,000 living species, making it the second-largest grouping of deuterostomes, after the chordates. Echinoderms are the largest entirely marine phylum. The first definitive echinoderms appeared near the start of the Cambrian. The echinoderms are important both ecologically and geologically. Ecologically, there are few other groupings so abundant in the biotic desert of the deep sea, as well as shallower oceans. Most echinoderms are able to reproduce asexually and regenerate tissue, organs, and limbs; in some cases, they can undergo complete regeneration from a single li ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diploporita
Diploporita is an extinct class of blastozoan that ranged from the Ordovician to the Devonian. These echinoderms are identified by a specialized respiratory structure, called diplopores. Diplopores are a double pore system that sit within a depression on a single thecal (body) plate; each plate can contain numerous diplopore pairs. The diploporitans likely represent a polyphyletic group. The evidence for this claim lies within the highly morphologically diverse body plans of the diploporitans: there are major differences in the makeup of the attachment structure (e.g., stem or holdfast), in the makeup of the feeding grooves, and even major differences in the construction of the group-defining diplopore respiratory structures. The only phylogenetic analysis of Diploporita to date indicates that Diploporita is not a natural evolutionary group. Rather, Diploporita is an artificial grouping based on the presence of diplopores, that have re-evolved multiple times throughout the echi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blastozoa
Blastozoa is a subphylum of extinct animals belonging to Phylum Echinodermata. This subphylum is characterized by the presence of specialized respiratory structures and brachiole plates used for feeding. This subphylum ranged from the Cambrian to the Permian The Permian ( ) is a geologic period and stratigraphic system which spans 47 million years from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.9 Mya. It is the last period of the Paleo .... References External linksHarvard: Subphylum Blastozoa Paleozoic echinoderms Cambrian echinoderms Silurian echinoderms Ordovician echinoderms Devonian echinoderms Permian echinoderms Animal subphyla {{paleo-echinoderm-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bolboporites
''Bolboporites'' is an extinct genus of conical echinoderms that lived in the Ordovician of Europe and North America. They are interpreted to have lived on the seafloor with the pointed end of the cone down in the sediment and the broad end upwards. A single brachiole extended from a hole in this top surface and bent into the current like the arms of crinoids (Rozhnov and Kushlina, 1994). It is likely an eocrinoid which diversified in the Baltic region The terms Baltic Sea Region, Baltic Rim countries (or simply the Baltic Rim), and the Baltic Sea countries/states refer to slightly different combinations of countries in the general area surrounding the Baltic Sea, mainly in Northern Europe. ... and then migrated to North America (Rozhnov, 2009). References Rozhnov, S.V. 2009. Eocrinoids and paracrinoids of the Baltic Ordovician basin: a biogeographical report. IGCP Meeting, Ordovician palaeogeography and palaeoclimate, Copenhagen, p. 16. Rozhnov, S.V. and Kushlina, V ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Holdfast (biology)
A holdfast is a root-like structure that anchors aquatic sessile organisms, such as seaweed, other sessile algae, stalked crinoids, benthic cnidarians, and sponges, to the substrate. Holdfasts vary in shape and form depending on both the species and the substrate type. The holdfasts of organisms that live in muddy substrates often have complex tangles of root-like growths. These projections are called haptera and similar structures of the same name are found on lichens. The holdfasts of organisms that live in sandy substrates are bulb-like and very flexible, such as those of sea pens, thus permitting the organism to pull the entire body into the substrate when the holdfast is contracted. The holdfasts of organisms that live on smooth surfaces (such as the surface of a boulder) have flattened bases which adhere to the surface. The organism derives no nutrition from this intimate contact with the substrate, as the process of liberating nutrients from the substrate requires ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Otto Jaekel
Otto Max Johannes Jaekel (21 February 1863 – 6 March 1929) was a German paleontologist and geologist. Biography Jaekel was born in Neusalz (Nowa Sól), Prussian Silesia, the son of a builder and the youngest of seven children. He studied at the ''Ritterakademie'' in Liegnitz (Legnica). After graduating in 1883, he came to study geology and paleontology under Ferdinand Roemer in Breslau (Wrocław) until 1885. Karl von Zittel awarded a PhD to Jaekel in Munich in 1886. Between 1887 and 1889, Jaekel was an assistant of E.W. Benecke at the Geologisch-Paläontologisches Institut in Straßburg, where he received his Habilitation. He worked at the Friedrich-Wilhelms-Universität Berlin and at the Geologisch-Paläontologisches Museum (a combined post) from 1894. Jaekel was considered as an ordinary professor of geology at the University of Vienna in 1903, but this was blocked by intrigue. Between 1906 and 1928, Jaekel was a professor at the University of Greifswald, where he fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silurian Echinoderms
The Silurian ( ) is a geologic period and system spanning 24.6 million years from the end of the Ordovician Period, at million years ago ( Mya), to the beginning of the Devonian Period, 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. One important event in this period was the initial establishment of terrestrial life in what is known as the Silurian-Devonian Terrestrial Revolution: vascular plants emerged from more primitive land plants, dikaryan fungi started expanding and diversifying along with glomeromycotan fungi, and three groups of arthropods ( myriapods, arachnids and hexapods) became fully terrestrialized. A significant evolutionary milestone durin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cambrian Echinoderms
The Cambrian Period ( ; sometimes symbolized Ꞓ) was the first geological period of the Paleozoic Era, and of the Phanerozoic Eon. The Cambrian lasted 53.4 million years from the end of the preceding Ediacaran Period 538.8 million years ago (mya) to the beginning of the Ordovician Period mya. Its subdivisions, and its base, are somewhat in flux. The period was established as "Cambrian series" by Adam Sedgwick, who named it after Cambria, the Latin name for 'Cymru' (Wales), where Britain's Cambrian rocks are best exposed. Sedgwick identified the layer as part of his task, along with Roderick Murchison, to subdivide the large "Transition Series", although the two geologists disagreed for a while on the appropriate categorization. The Cambrian is unique in its unusually high proportion of sedimentary deposits, sites of exceptional preservation where "soft" parts of organisms are preserved as well as their more resistant shells. As a result, our understanding of the Cambrian biol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paleozoic Echinoderms
The Paleozoic (or Palaeozoic) Era is the earliest of three geologic eras of the Phanerozoic Eon. The name ''Paleozoic'' ( ;) was coined by the British geologist Adam Sedgwick in 1838 by combining the Greek words ''palaiós'' (, "old") and ''zōḗ'' (), "life", meaning "ancient life" ). It is the longest of the Phanerozoic eras, lasting from , and is subdivided into six geologic periods (from oldest to youngest): # Cambrian # Ordovician # Silurian # Devonian # Carboniferous # Permian The Paleozoic comes after the Neoproterozoic Era of the Proterozoic Eon and is followed by the Mesozoic Era. The Paleozoic was a time of dramatic geological, climatic, and evolutionary change. The Cambrian witnessed the most rapid and widespread diversification of life in Earth's history, known as the Cambrian explosion, in which most modern phyla first appeared. Arthropods, molluscs, fish, amphibians, reptiles, and synapsids all evolved during the Paleozoic. Life began in the ocean but event ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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