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Pentapycnon Geayi
''Pentapycnon geayi'' is a species of sea spider (class Pycnogonida) in the family Pycnogonidae. As the genus name ''Pentapycnon'' suggests, the sea spider ''P. geayi'' is among the seven species of sea spiders with five pairs of legs in adults rather than the usual four leg pairs. The species ''P. geayi'' is found in the Caribbean Sea, the tropical Atlantic Ocean, and the Mediterranean Sea. This species is one of only two species of polymerous (i.e., extra-legged) sea spiders found outside the Southern Ocean. Discovery This species was first described in 1911 by the French zoologist Eugène Louis Bouvier. He based the original description of this species on numerous specimens including both sexes found off the coast of French Guiana near the city of Cayenne. He named this species in memory of the late French naturalist Martin François Geay, who collected these specimens. Description This species is small, with the average trunk measuring only 3.5 mm in length. This sea sp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eugene Louis Bouvier
Eugene may refer to: People and fictional characters * Eugene (given name), including a list of people and fictional characters with the given name * Gene Eugene, stage name of Canadian born actor, record producer, engineer, composer and musician Gene Andrusco (1961–2000) * Eugene (wrestler), professional wrestler Nick Dinsmore * Eugene (actress) (born 1981), Kim Yoo-jin, South Korean actress and former member of the singing group S.E.S. Places Canada * Mount Eugene, in Nunavut; the highest mountain of the United States Range on Ellesmere Island United States * Eugene, Oregon, a city ** Eugene, OR Metropolitan Statistical Area ** Eugene (Amtrak station) * Eugene Apartments, NRHP-listed apartment complex in Portland, Oregon * Eugene, Indiana, an unincorporated town * Eugene, Missouri, an unincorporated town Business * Eugene Green Energy Standard, or EUGENE, an international standard to which electricity labelling schemes can be accredited to confirm that they pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
French Guiana
French Guiana, or Guyane in French, is an Overseas departments and regions of France, overseas department and region of France located on the northern coast of South America in the Guianas and the West Indies. Bordered by Suriname to the west and Brazil to the east and south, French Guiana covers a total area of and a land area of . As of January 2025, it is home to 292,354 people. French Guiana is the second-largest Regions of France, region in France, being approximately one-seventh the size of metropolitan France, European France, and the largest Special member state territories and the European Union, outermost region within the European Union. It has a very low population density, with only . About half of its residents live in its capital, Cayenne. Approximately 98.9% of French Guiana is covered by forests, much of it Old-growth forest, primeval Tropical rainforest, rainforest. Guiana Amazonian Park, the largest national park in the European Union covers 41% of French ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pycnogonum Reticulatum
''Pycnogonum'' is a genus of sea spiders in the family Pycnogonidae. It is the type genus of the family. Etymology The generic name (biology), generic name literally means “dense knees”. ''Pycnogonum'' combines the prefix ' (from ‘dense’ in Greek) with the Greek word for "knee": (). Characteristics Members of the genus ''Pycnogonum'' have squarish bodies with a tough integument and a few hairs. The cephalon (the anterior end of the body which is fused with the first segment of the trunk) has a long smooth proboscis and a low tubercle on which the eyes are set. There are no chelicerae or Pedipalp, palps and these sea spiders use their proboscis to suck juices from their Predation, prey. On the first segment of the trunk of males there are small ovigerous legs with nine segments. The larvae are carried around by the males on these appendages. The four pairs of ambulatory legs are short but strong, with well-developed terminal claws. The genital openings are on the second ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyphyly
A polyphyletic group is an assemblage that includes organisms with mixed evolutionary origin but does not include their most recent common ancestor. The term is often applied to groups that share similar features known as homoplasies, which are explained as a result of convergent evolution. The arrangement of the members of a polyphyletic group is called a polyphyly .. ource for pronunciation./ref> It is contrasted with monophyly and paraphyly. For example, the biological characteristic of warm-bloodedness evolved separately in the ancestors of mammals and the ancestors of birds; "warm-blooded animals" is therefore a polyphyletic grouping. Other examples of polyphyletic groups are algae, C4 photosynthetic plants, and edentates. Many taxonomists aim to avoid homoplasies in grouping taxa together, with a goal to identify and eliminate groups that are found to be polyphyletic. This is often the stimulus for major revisions of the classification schemes. Researchers concerned m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paraphyly
Paraphyly is a taxonomic term describing a grouping that consists of the grouping's last common ancestor and some but not all of its descendant lineages. The grouping is said to be paraphyletic ''with respect to'' the excluded subgroups. In contrast, a monophyletic grouping (a clade) includes a common ancestor and ''all'' of its descendants. The terms are commonly used in phylogenetics (a subfield of biology) and in the tree model of historical linguistics. Paraphyletic groups are identified by a combination of synapomorphies and symplesiomorphies. If many subgroups are missing from the named group, it is said to be polyparaphyletic. The term received currency during the debates of the 1960s and 1970s accompanying the rise of cladistics, having been coined by zoologist Willi Hennig to apply to well-known taxa like Reptilia (reptiles), which is paraphyletic with respect to birds. Reptilia contains the last common ancestor of reptiles and all descendants of that ancest ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sister Group
In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and taxon B are sister groups to each other. Taxa A and B, together with any other extant or extinct descendants of their most recent common ancestor (MRCA), form a monophyletic group, the clade AB. Clade AB and taxon C are also sister groups. Taxa A, B, and C, together with all other descendants of their MRCA form the clade ABC. The whole clade ABC is itself a subtree of a larger tree which offers yet more sister group relationships, both among the leaves and among larger, more deeply rooted clades. The tree structure shown connects through its root to the rest of the universal tree of life. In cladistic standards, taxa A, B, and C may represent specimens, species, genera, or any other taxonomic units. If A and B are at the same taxono ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pycnogonum Cesairei
''Pycnogonum'' is a genus of sea spiders in the family Pycnogonidae. It is the type genus of the family. Etymology The generic name literally means “dense knees”. ''Pycnogonum'' combines the prefix ' (from ‘dense’ in Greek) with the Greek word for "knee": (). Characteristics Members of the genus ''Pycnogonum'' have squarish bodies with a tough integument and a few hairs. The cephalon (the anterior end of the body which is fused with the first segment of the trunk) has a long smooth proboscis and a low tubercle on which the eyes are set. There are no chelicerae or palps and these sea spiders use their proboscis to suck juices from their prey. On the first segment of the trunk of males there are small ovigerous legs with nine segments. The larvae are carried around by the males on these appendages. The four pairs of ambulatory legs are short but strong, with well-developed terminal claws. The genital openings are on the second segment of the posterior pair of legs. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clade
In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach to taxonomy adopted by most biological fields. The common ancestor may be an individual, a population, or a species (extinct or Extant taxon, extant). Clades are nested, one in another, as each branch in turn splits into smaller branches. These splits reflect evolutionary history as populations diverged and evolved independently. Clades are termed ''monophyletic'' (Greek: "one clan") groups. Over the last few decades, the cladistic approach has revolutionized biological classification and revealed surprising evolutionary relationships among organisms. Increasingly, taxonomists try to avoid naming Taxon, taxa that are not clades; that is, taxa that are not Monophyly, monophyletic. Some of the relationships between organisms that the molecul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phylogenetic Tree
A phylogenetic tree or phylogeny is a graphical representation which shows the evolutionary history between a set of species or taxa during a specific time.Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, MA. In other words, it is a branching diagram or a tree showing the evolutionary relationships among various biological species or other entities based upon similarities and differences in their physical or genetic characteristics. In evolutionary biology, all life on Earth is theoretically part of a single phylogenetic tree, indicating common ancestry. Phylogenetics is the study of phylogenetic trees. The main challenge is to find a phylogenetic tree representing optimal evolutionary ancestry between a set of species or taxa. Computational phylogenetics (also phylogeny inference) focuses on the algorithms involved in finding optimal phylogenetic tree in the phylogenetic landscape. Phylogenetic trees may be rooted or unrooted. In a ''rooted'' p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pycnogonum
''Pycnogonum'' is a genus of sea spiders in the family Pycnogonidae. It is the type genus of the family. Etymology The generic name (biology), generic name literally means “dense knees”. ''Pycnogonum'' combines the prefix ' (from ‘dense’ in Greek) with the Greek word for "knee": (). Characteristics Members of the genus ''Pycnogonum'' have squarish bodies with a tough integument and a few hairs. The cephalon (the anterior end of the body which is fused with the first segment of the trunk) has a long smooth proboscis and a low tubercle on which the eyes are set. There are no chelicerae or Pedipalp, palps and these sea spiders use their proboscis to suck juices from their Predation, prey. On the first segment of the trunk of males there are small ovigerous legs with nine segments. The larvae are carried around by the males on these appendages. The four pairs of ambulatory legs are short but strong, with well-developed terminal claws. The genital openings are on the second ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phylogenetics
In biology, phylogenetics () is the study of the evolutionary history of life using observable characteristics of organisms (or genes), which is known as phylogenetic inference. It infers the relationship among organisms based on empirical data and observed heritable traits of DNA sequences, protein amino acid sequences, and morphology. The results are a phylogenetic tree—a diagram depicting the hypothetical relationships among the organisms, reflecting their inferred evolutionary history. The tips of a phylogenetic tree represent the observed entities, which can be living taxa or fossils. A phylogenetic diagram can be rooted or unrooted. A rooted tree diagram indicates the hypothetical common ancestor of the taxa represented on the tree. An unrooted tree diagram (a network) makes no assumption about directionality of character state transformation, and does not show the origin or "root" of the taxa in question. In addition to their use for inferring phylogenetic pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pentapycnon Charcoti
''Pentapycnon charcoti'' is a species of sea spider (class Pycnogonida) in the family Pycnogonidae. As the genus name ''Pentapycnon'' suggests, the sea spider ''P.'' ''charcoti'' is among the seven species of sea spiders with five pairs of legs in adults rather than the usual four leg pairs. This species is found in the Southern Ocean. Discovery This species was first described in 1911 by the French zoologist Eugène Louis Bouvier based on three specimens, including an adult male type specimen. He originally described the other two specimens as females but later found them to be male juveniles. These three specimens were dredged from a depth of 420 meters below the surface in Admiralty Bay on King George Island in the South Shetland Islands of Antarctica. Bouvier named this species for the French scientist Jean-Baptiste Charcot, who led the Antarctic expedition on the ship '' Pourquoi-Pas'' that collected these specimens. The first female specimens on record were described in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
