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Branchiostoma Bennetti
''Branchiostoma bennetti'', the mud lancelet, is a lancelet of the genus '' Branchiostoma'' endemic to the Gulf of Mexico, where it is found in the northern part. Description Like other lancelets in the genus ''Branchiostoma'', ''B. bennetti'' occurs in inshore waters where it burrows into sand or muddy sand at depths down to about . The body is laterally flattened and pointed at both ends. It has a long dorsal fin and another fin on its ventral surface, and a caudal fin at the rear end. ''B. bennetti'' differs from other western Atlantic lancelets for having the longest buccal cirri Buccal cirri are feeding structures found in the oral hood of primitive jawless organisms called amphioxus. The word buccal is derived from the term ''bucca'' which means "cheek" and cirri is derived from the Latin word ''cerrus'' meaning a tendril ... among them. These cirri are further unique in this region because of their extended lateral projections. It is presumed that these unique buccal ci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lancelet
The lancelets ( or ), also known as amphioxi (singular: amphioxus ), consist of some 30 to 35 species of "fish-like" benthic filter feeding chordates in the order Amphioxiformes. They are the modern representatives of the subphylum Cephalochordata. Lancelets closely resemble 530-million-year-old ''Pikaia'', fossils of which are known from the Burgess Shale. Zoologists are interested in them because they provide evolutionary insight into the origins of vertebrates. Lancelets contain many organs and organ systems that are closely related to those of modern fish, but in more primitive form. Therefore, they provide a number of examples of possible evolutionary exaptation. For example, the gill-slits of lancelets are used for feeding only, and not for respiration. The circulatory system carries food throughout their body, but does not have red blood cells or hemoglobin for transporting oxygen. Lancelet genomes hold clues about the early evolution of vertebrates: by comparing genes from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Branchiostoma
''Branchiostoma'' is one of the few living genus, genera of lancelets (order (biology), order Amphioxiformes). It is the type (zoology), type genus of family (biology), family Branchiostomatidae. These small vaguely eel- or snake-like animals are close relatives of vertebrates. The scientific name means "gill-mouth", referring to their anatomy – unlike vertebrates, they do not have a true head (with a skull capsule, eyes, nose, a well-developed brain etc.), but merely a mouth adjacent to the gill-slits, with the slightly enlarged anterior end of the dorsal nerve cord above and in front of them. It dislikes the light. Like all lancelets, they are filter feeders that hide in the sediment most of the time. The genus inhabits coastal waters throughout the world. Species * ''Branchiostoma africae'' Hubbs, 1927 * ''Branchiostoma arabiae'' Webb, 1957 * ''Branchiostoma bazarutense'' Gilchrist, 1923 * ''Branchiostoma belcheri'' Gray, 1847 (Belcher's lancelet) * ''Branchiostoma ben ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endemism
Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsewhere. For example, the Cape sugarbird is found exclusively in southwestern South Africa and is therefore said to be ''endemic'' to that particular part of the world. An endemic species can be also be referred to as an ''endemism'' or in scientific literature as an ''endemite''. For example ''Cytisus aeolicus'' is an endemite of the Italian flora. ''Adzharia renschi'' was once believed to be an endemite of the Caucasus, but it was later discovered to be a non-indigenous species from South America belonging to a different genus. The extreme opposite of an endemic species is one with a cosmopolitan distribution, having a global or widespread range. A rare alternative term for a species that is endemic is "precinctive", which applies t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gulf Of Mexico
The Gulf of Mexico ( es, Golfo de México) is an ocean basin and a marginal sea of the Atlantic Ocean, largely surrounded by the North American continent. It is bounded on the northeast, north and northwest by the Gulf Coast of the United States; on the southwest and south by the Mexican states of Tamaulipas, Veracruz, Tabasco, Campeche, Yucatan, and Quintana Roo; and on the southeast by Cuba. The Southern U.S. states of Texas, Louisiana, Mississippi, Alabama, and Florida, which border the Gulf on the north, are often referred to as the " Third Coast" of the United States (in addition to its Atlantic and Pacific coasts). The Gulf of Mexico took shape approximately 300 million years ago as a result of plate tectonics.Huerta, A.D., and D.L. Harry (2012) ''Wilson cycles, tectonic inheritance, and rifting of the North American Gulf of Mexico continental margin.'' Geosphere. 8(1):GES00725.1, first published on March 6, 2012, The Gulf of Mexico basin is roughly ov ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Buccal Cirri
Buccal cirri are feeding structures found in the oral hood of primitive jawless organisms called amphioxus. The word buccal is derived from the term ''bucca'' which means "cheek" and cirri is derived from the Latin word ''cerrus'' meaning a tendril or a small and flexible appendage. Structure Cirri, plural for cirrus, are small, filament-like appendages that act like tentacles. Tentacles are elongated appendages from the cephalic region of organisms that aid in sensory and locomotive abilities. Buccal cirri extend from the oral hood on the anterior portion of the organism. The buccal cirri possess receptors, some of which are believed to be mechanoreceptors. Mechanoreceptors are sensory receptors on the surface of the body. The presence of external particles can be detected by an organism possessing buccal cirri due to the sensory abilities associated with the mechanoreceptors. Additionally, the touch and pressure sensory receptors aid in the mechanical sorting of food particles. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cephalochordata
A cephalochordate (from Greek: κεφαλή ''kephalé'', "head" and χορδή ''khordé'', "chord") is an animal in the chordate subphylum, Cephalochordata. They are commonly called lancelets. Cephalochordates possess 5 synapomorphies, or primary characteristics, that all chordates have at some point during their larval or adulthood stages. These 5 synapomorphies include a notochord, dorsal hollow nerve cord, endostyle, pharyngeal slits, and a post-anal tail (see chordate for descriptions of each). The fine structure of the cephalochordate notochord is best known for the Bahamas lancelet, ''Asymmetron lucayanum''. Cephalochordates are represented in modern oceans by the Amphioxiformes and are commonly found in warm temperate and tropical seas worldwide. With the presence of a notochord, adult amphioxus are able to swim and tolerate the tides of coastal environments, but they are most likely to be found within the sediment of these communities. Cephalochordates are segmented mar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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