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Hemicidaridae
''Hemicidaridae'' is a family of extinct sea urchins characterized by large, massive, club-shaped spines. These epifaunal grazer-deposit feeders lived in Jurassic and Cretaceous ages (from 189.6 to 112.6 Ma). Taxonomy List of genera and subfamilies: * Subfamily Hemicidarinae Wright, 1857 †:''Asterocidaris ''Asterocidaris'' is a genus of fossils sea urchins in the family Hemicidaridae. These epifaunal grazer-deposit feeders lived in the Middle and Upper Jurassic age (from 171.6 to 161.2 Ma). Species * ''Asterocidaris besairiei'' Lambert, 1936 †...'' Cotteau, 1859 †:'' Gymnocidaris'' L. Agassiz, 1838 †: '' Hemicidaris'' L. Agassiz, 1838 †* Subfamily Pseudocidarinae Smith & Wright, 1993 †:'' Cidaropsis'' Cotteau, 1863 †:'' Pseudocidaris'' Pomel, 1883 †:'' Gymnocidaris'' L. Agassiz, 1838 †: '' Hemicidaris (Sphaerotiaris)'' Lambert & Thiéry, 1914 †Distribution Fossils of species within this genus have been found in the Jurassic and Cretaceous ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asterocidaris
''Asterocidaris'' is a genus of fossils sea urchins in the family Hemicidaridae ''Hemicidaridae'' is a family of extinct sea urchins characterized by large, massive, club-shaped spines. These epifaunal grazer-deposit feeders lived in Jurassic and Cretaceous ages (from 189.6 to 112.6 Ma). Taxonomy List of genera and subfa .... These epifaunal grazer-deposit feeders lived in the Middle and Upper Jurassic age (from 171.6 to 161.2 Ma). Species * ''Asterocidaris besairiei'' Lambert, 1936 †* ''Asterocidaris meandrina'' (Agassiz 1840) †* ''Asterocidaris ragoti'' Lambert, 1936 †Description These fossil spined echinoid sea urchins can reach a diameter of about , with spicules of about 69x60mm. They are hemispherical, flattened beneath, with small apical disc. Distribution Fossils of species within this genus have been found in the Middle to Upper Jurassic sediments (Bajocian-Oxfordian) in Europe, Madagascar and Africa ( Morocco).Smith, A. B. & Kroh, A. (editor) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jurassic
The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The Jurassic constitutes the middle period of the Mesozoic, Mesozoic Era and is named after the Jura Mountains, where limestone strata from the period were first identified. The start of the Jurassic was marked by the major Triassic–Jurassic extinction event, associated with the eruption of the Central Atlantic magmatic province, Central Atlantic Magmatic Province. The beginning of the Toarcian Stage started around 183 million years ago and is marked by an extinction event associated with widespread Anoxic event, oceanic anoxia, ocean acidification, and elevated temperatures likely caused by the eruption of the Karoo-Ferrar, Karoo-Ferrar large igneous provinces. The end of the Jurassic, however, has no clear boundary with the Cretaceous and i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cretaceous
The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of the entire Phanerozoic. The name is derived from the Latin ''creta'', "chalk", which is abundant in the latter half of the period. It is usually abbreviated K, for its German translation ''Kreide''. The Cretaceous was a period with a relatively warm climate, resulting in high eustatic sea levels that created numerous shallow inland seas. These oceans and seas were populated with now- extinct marine reptiles, ammonites, and rudists, while dinosaurs continued to dominate on land. The world was ice free, and forests extended to the poles. During this time, new groups of mammals and birds appeared. During the Early Cretaceous, flowering plants appeared and began to rapidly diversify, becoming the dominant group of plants across the Earth b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sea Urchin
Sea urchins () are spiny, globular echinoderms in the class Echinoidea. About 950 species of sea urchin live on the seabed of every ocean and inhabit every depth zone from the intertidal seashore down to . The spherical, hard shells (tests) of sea urchins are round and spiny, ranging in diameter from . Sea urchins move slowly, crawling with tube feet, and also propel themselves with their spines. Although algae are the primary diet, sea urchins also eat slow-moving (sessile) animals. Predators that eat sea urchins include a wide variety of fish, starfish, crabs, marine mammals. Sea urchins are also used as food especially in Japan. Adult sea urchins have fivefold symmetry, but their pluteus larvae feature bilateral (mirror) symmetry, indicating that the sea urchin belongs to the Bilateria group of animal phyla, which also comprises the chordates and the arthropods, the annelids and the molluscs, and are found in every ocean and in every climate, from the tropics to the pol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hemicidaris
''Hemicidaris'' is an extinct genus of echinoids that lived from the Middle Jurassic to the Early Cretaceous. Its remains have been found in Africa, Asia, and Europe. Sources * ''Fossils'' (Smithsonian Handbooks) by David Ward (Page 178) External links''Hemicidaris''in the Paleobiology Database The Paleobiology Database is an online resource for information on the distribution and classification of fossil animals, plants, and microorganisms. History The Paleobiology Database (PBDB) originated in the NCEAS-funded Phanerozoic Marine Pale ... Hemicidaroida Prehistoric echinoid genera Jurassic echinoderms Cretaceous echinoderms Prehistoric echinoderms of Africa Prehistoric echinoderms of Asia Prehistoric echinoderms of Europe Middle Jurassic genus first appearances Early Cretaceous genus extinctions Fossil taxa described in 1838 {{paleo-echinoidea-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prehistoric Echinoderm Families
Prehistory, also known as pre-literary history, is the period of human history between the use of the first stone tools by hominins 3.3 million years ago and the beginning of recorded history with the invention of writing systems. The use of symbols, marks, and images appears very early among humans, but the earliest known writing systems appeared 5000 years ago. It took thousands of years for writing systems to be widely adopted, with writing spreading to almost all cultures by the 19th century. The end of prehistory therefore came at very different times in different places, and the term is less often used in discussing societies where prehistory ended relatively recently. In the early Bronze Age, Sumer in Mesopotamia, the Indus Valley Civilisation, and ancient Egypt were the first civilizations to develop their own scripts and to keep historical records, with their neighbors following. Most other civilizations reached the end of prehistory during the following Iron Age. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
