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Rotulidae
Rotulidae is a family of small sand dollars native to the Atlantic coast of Africa, with 3 genera, with ''Rotula'' and ''Heliophora'' being extant, the other, ''Rotuloidea'', being extinct since the Pliocene, but all three being found in the fossil record along the Atlantic African coast since the Miocene. Morphology The generalized rotulid has a circular to oval-shaped test, and indentations starting along the posterior edge. In ''Heliophora'', the indentations may remain restricted to the posterior edge, or they may reach to the anterior edges of the test. Depending on the individual, the indentations may be very shallow, or very deep, forming very long "fingers," or digits. While rotulids are very distinctive in appearance, they are also highly morphic, with a tremendous diversity seen in individual specimens. That the digits are very fragile, and prone to breaking off and regenerating only adds to individual variations. In the genus ''Heliophora'', the test is extremely v ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heliophora
''Heliophora orbicularis'', also known as the West African Sand Dollar, is a small sand dollar in to the family Rotulidae, and the only species in the genus ''Heliophora''. It, and other members of Rotulidae have been found in West African marine strata from the Late Miocene onward. Like the related , it is still extant. Description Individuals of ''H. orbicularis'' are very distinctive in appearance and also highly morphic, with a remarkable diversity in individual specimens. This genus has an extremely variable circular to oval-shaped test. The indentations may remain restricted to the posterior edge or may be found along the entire margin of the test. The indentations may be very shallow or quite deep, forming long "fingers," or digits. The digits are very fragile, and prone to breaking off. Ecology and feeding ''Heliophora orbicularis'' live in large groups in very shallow water of lagoons and estuaries, usually lightly buried in mud. Food particles are picked out of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heliophora Orbiculus
''Heliophora orbicularis'', also known as the West African Sand Dollar, is a small sand dollar in to the family Rotulidae, and the only species in the genus ''Heliophora''. It, and other members of Rotulidae have been found in West African marine strata from the Late Miocene onward. Like the related , it is still extant. Description Individuals of ''H. orbicularis'' are very distinctive in appearance and also highly morphic, with a remarkable diversity in individual specimens. This genus has an extremely variable circular to oval-shaped test. The indentations may remain restricted to the posterior edge or may be found along the entire margin of the test. The indentations may be very shallow or quite deep, forming long "fingers," or digits. The digits are very fragile, and prone to breaking off. Ecology and feeding ''Heliophora orbicularis'' live in large groups in very shallow water of lagoons and estuaries, usually lightly buried in mud. Food particles are picked out of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clypeasteroida
Sand dollars (also known as a sea cookie or snapper biscuit in New Zealand, or pansy shell in South Africa) are species of flat, burrowing sea urchins belonging to the order Clypeasteroida. Some species within the order, not quite as flat, are known as '' sea biscuits''. Sand dollars can also be called "sand cakes" or "cake urchins". Anatomy Sand dollars are small in size, averaging from three to four inches. As with all members of the order Clypeasteroida, they possess a rigid skeleton called a test. The test consists of calcium carbonate plates arranged in a fivefold symmetric pattern. The test of certain species of sand dollar have slits called lunules that can help the animal stay embedded in the sand to stop it from being swept away by an ocean wave. In living individuals, the test is covered by a skin of velvet-textured spines which are covered with very small hairs (cilia). Coordinated movements of the spines enable sand dollars to move across the seabed. The velvety ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sand Dollar
Sand dollars (also known as a sea cookie or snapper biscuit in New Zealand, or pansy shell in South Africa) are species of flat, burrowing sea urchins belonging to the order Clypeasteroida. Some species within the order, not quite as flat, are known as '' sea biscuits''. Sand dollars can also be called "sand cakes" or "cake urchins". Anatomy Sand dollars are small in size, averaging from three to four inches. As with all members of the order Clypeasteroida, they possess a rigid skeleton called a test. The test consists of calcium carbonate plates arranged in a fivefold symmetric pattern. The test of certain species of sand dollar have slits called lunules that can help the animal stay embedded in the sand to stop it from being swept away by an ocean wave. In living individuals, the test is covered by a skin of velvet-textured spines which are covered with very small hairs (cilia). Coordinated movements of the spines enable sand dollars to move across the seabed. The velvety ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rotula Deciesdigitatus
''Rotula deciesdigitatus'' is a species of echinoderm in the monotypic genus ''Rotula'', belonging to the family Rotulidae Rotulidae is a family of small sand dollars native to the Atlantic coast of Africa, with 3 genera, with ''Rotula'' and ''Heliophora'' being extant, the other, ''Rotuloidea'', being extinct since the Pliocene, but all three being found in the fos .... The species is found in Europe and Western Africa. References Clypeasteroida Animals described in 1778 {{echinoidea-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Miocene
The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recent" because it has 18% fewer modern marine invertebrates than the Pliocene has. The Miocene is preceded by the Oligocene and is followed by the Pliocene. As Earth went from the Oligocene through the Miocene and into the Pliocene, the climate slowly cooled towards a series of ice ages. The Miocene boundaries are not marked by a single distinct global event but consist rather of regionally defined boundaries between the warmer Oligocene and the cooler Pliocene Epoch. During the Early Miocene, the Arabian Peninsula collided with Eurasia, severing the connection between the Mediterranean and Indian Ocean, and allowing a faunal interchange to occur between Eurasia and Africa, including the dispersal of proboscideans into Eurasia. During the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MNHN
The French National Museum of Natural History, known in French as the ' (abbreviation MNHN), is the national natural history museum of France and a ' of higher education part of Sorbonne Universities. The main museum, with four galleries, is located in Paris, France, within the Jardin des Plantes on the left bank of the River Seine. It was formally founded in 1793 during the French Revolution, but was begun even earlier in 1635 as the royal garden of medicinal plants. The museum now has 14 sites throughout France. History 17th–18th century File:Jardin du roi 1636.png, The Royal Garden of Medicinal Plants in 1636 File:Buffon statue dsc00979.jpg, Statue of Georges-Louis Leclerc, Comte de Buffon in the formal garden File:Buffon, Georges Louis - Leclerc, comte de – Histoire naturelle, générale et particuliére, 1763 – BEIC 8822844.jpg, Buffon's "Natural History" (1763) File:MNHN-logo.jpg, The museum's seal, designed in 1793, illustrates the three realms of Nature, Collectiv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rotula
A ''rotulus'' (plural ''rotuli'') or ''rotula'' (pl. ''rotulae'') is often referred to as a "vertical roll," is a long and narrow strip of writing material, historically papyrus or parchment, that is wound around a wooden axle or rod. Rotuli are unwound vertically so that the writing runs parallel to the rod, unlike the other kind of roll, called a " scroll", whose writing runs perpendicular to the rod in multiple columns. Historical Use Specific legal records in Europe, from which is still derived the title of the judicial functionary denominated the "Master of the Rolls", and the Byzantine Empire. Rotuli also have been used as Liturgical manuscripts, e.g., those used for chanting the '' Exultet''. Additionally, mortuary rolls, i.e., documents memorializing the names of all the deceased members of a monastery or other institution, which were banded together and circulated so that they could mutually pray for the repose of each other's decedents. See also * Codex * S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
