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Sharpsnout Stingray
The sharpsnout stingray or wingfin stingray (''Dasyatis geijskesi'') is a species of stingray in the family Dasyatidae, found from off Venezuela to northern Brazil. It inhabits shallow, brackish water, shifting towards the coast in the dry season and away from it in the rainy season. Typically measuring across, this dark brown ray is easily identifiable by its long, projecting snout and elongated, acutely pointed pelvic fins. Its diet consists of bottom-dwelling invertebrates. Reproduction is aplacental viviparous, with females bearing one to three pups annually. Naturally uncommon and slow-reproducing, the sharpnose stingray is under pressure by both artisanal and commercial fisheries, leading the International Union for Conservation of Nature (IUCN) to assess it as critically endangered. Taxonomy and phylogeny Dutch ichthyologist Marinus Boeseman described the sharpsnout stingray in a 1948 issue of the scientific journal ''Zoologische Mededelingen'', based on a juvenile male c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marinus Boeseman
Marinus may refer to: *Marinus (crater), a crater on the Moon *Marinus (given name) Marinus is a male given name, derived from Latin ''marinus'' meaning "marine; of or pertaining to the sea". It is used in the Netherlands as a given name, though most people use a short form in daily life, like ''Marijn'', ''Mario'', '' René'', '' ..., for people named Marinus *Dr. Marinus, a recurring character in the novels of David Mitchell See also *'' The Keys of Marinus'', a serial in the ''Doctor Who'' TV series {{disambig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ichthyologist
Ichthyology is the branch of zoology devoted to the study of fish, including bony fish (Osteichthyes), cartilaginous fish (Chondrichthyes), and jawless fish (Agnatha). According to FishBase, 33,400 species of fish had been described as of October 2016, with approximately 250 new species described each year. Etymology The word is derived from the Greek words wikt:ἰχθύς, ἰχθύς, ''ikhthus'', meaning "fish"; and wikt:-λογία, λογία, ''logia'', meaning "to study". History The study of fish dates from the Upper Paleolithic, Upper Paleolithic Revolution (with the advent of "high culture"). The science of ichthyology was developed in several interconnecting epochs, each with various significant advancements. The study of fish receives its origins from humans' desire to feed, clothe, and equip themselves with useful implements. According to Michael Barton (professor), Michael Barton, a prominent ichthyologist and professor at Centre College, "the earliest ichthyolo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Outgroup (cladistics)
In cladistics or phylogenetics, an outgroup is a more distantly related group of organisms that serves as a reference group when determining the evolutionary relationships of the ingroup, the set of organisms under study, and is distinct from sociological outgroups. The outgroup is used as a point of comparison for the ingroup and specifically allows for the phylogeny to be rooted. Because the polarity (direction) of character change can be determined only on a rooted phylogeny, the choice of outgroup is essential for understanding the evolution of traits along a phylogeny. History Although the concept of outgroups has been in use from the earliest days of cladistics, the term "outgroup" is thought to have been coined in the early 1970s at the American Museum of Natural History. Prior to the advent of the term, various other terms were used by evolutionary biologists, including "exgroup", "related group", and "outside groups". Choice of outgroup The chosen outgroup is hypothe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Smooth Butterfly Ray
The smooth butterfly ray (''Gymnura micrura'') is a species of cartilaginous fish in the family Gymnuridae. It is a member of the order Myliobatiformes, which contains 10 total families. Its natural habitats are shallow seas, subtidal aquatic beds, estuarine waters, and coastal saline lagoons. Its common name is derived from its compressed body, pectoral fins that are wider than their length, and overall diamond shape. Taxonomy Gymnura is derived from Greek roots and translates into 'naked tail'. They belong to a monophyletic group of Batoid fish. This group contains over 500 other elasmobranch fishes which includes electric rays, sawfishes, guitarfishes, skates, and stingrays. They are a part of Order Myliobatiformes and are characterized by their pectoral fins being widely expanded and fused to their heads. The family Gymnuridae contains 2 genera which encompass 12 different species. Description These are broad diamond-shaped rays with a short tail that has low ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Himantura Gerrardi
The whitespotted whipray or sharpnose stingray (''Maculabatis gerrardi'') is a species of stingray in the family Dasyatidae. It is found in coastal regions including estuaries, in the Indo-Pacific, and has also been recorded in the Ganges River.Ishihara, H. & Taniuchi, T. & Tanaka, Sho & Srivastava, M.P. (1998) Investigation of the freshwater elasmobranchs in the River Ganges. In Adaptability and conservation of freshwater elasmobranchs. Report of Research Project, Grant–in–Aid for International Scientific Research(Field Research) in the financial year of 1996 and 1997: 41–55 It reaches a maximum disc width of . As presently defined, it is probably a species complex. Etymology The Stingray is named in honor of Edward Gerrard (1810-1910), a taxidermist at the British Museum The British Museum is a public museum dedicated to human history, art and culture located in the Bloomsbury area of London. Its permanent collection of eight million works is among the largest an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pearl Stingray
The pearl stingray (''Dasyatis margaritella'') is a little-known species of stingray in the family Dasyatidae, found in shallow coastal waters from Mauritania to Angola. Growing to across, this species has a rounded pectoral fin disc with a pointed snout, and a wide band of dermal denticles over the back in adults. It closely resembles and is often confused for the much larger daisy stingray (''D. margarita''); both species are characterized by the presence of an enlarged, nacreous denticle in the middle of the back called a "pearl spine". The International Union for Conservation of Nature (IUCN) assesses the pearl stingray's conservation status as Near Threatened, but it is likely that most of the historically reported fishery catches of the daisy stingray were in fact of this species. Taxonomy and phylogeny Prior to being described by Leonard Compagno and Tyson Roberts, in a 1984 paper for the ''Proceedings of the California Academy of Sciences'', the pearl stingray was g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pale-edged Stingray
The pale-edged stingray or sharpnose stingray (''Dasyatis zugei'') is a species of stingray in the family Dasyatidae, found in the Indian and Pacific Oceans from India to the western Malay Archipelago and southern Japan. This bottom-dwelling ray is most commonly found over sandy areas shallower than , as well as in estuaries. Measuring up to across, the pale-edged stingray has a diamond-shaped pectoral fin disc, a long projecting snout, small eyes, and a whip-like tail with both dorsal and ventral fin folds. It is chocolate brown above and white below. The diet of the pale-edged stingray consists mainly of small crustaceans and fishes. Reproduction is aplacental viviparous, with females bearing litters of 1–3 young. Caught as bycatch and utilized for its meat, this species is threatened by heavy fishing pressure throughout its range and has been assessed as Vulnerable by the International Union for Conservation of Nature (IUCN). Taxonomy and phylogeny German biologists ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clade
A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, the equivalent Latin term ''cladus'' (plural ''cladi'') is often used in taxonomical literature. The common ancestor may be an individual, a population, or a species (extinct or 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 taxa that are not clades; that is, taxa that are not monophyletic. Some of the relationships between org ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sister Species
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] |
Longnose Stingray
The longnose stingray (''Dasyatis guttata'') is a species of stingray in the family Dasyatidae, native to the western Atlantic Ocean from the southern Gulf of Mexico to Brazil. Found in coastal waters no deeper than , this demersal species favors muddy or sandy habitats. The longnose stingray is characterized by its angular, rhomboid pectoral fin disc, moderately projecting snout, and whip-like tail with a dorsal keel and ventral fin fold. It typically grows to across and is brownish above and light-colored below. Longnose stingrays feed mainly on bottom-dwelling invertebrates and small bony fishes. Reproduction is aplacental viviparous, with females bearing two litters of 1–2 pups per year. The young are born in relatively fresh water, move into saltier water as juveniles, and then back into fresher water as adults. This species is valued by commercial and recreational fishers in many parts of its range, and utilized for meat, gelatin, oil, and even the aquarium trade. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Morphology (biology)
Morphology is a branch of biology dealing with the study of the form and structure of organisms and their specific structural features. This includes aspects of the outward appearance ( shape, structure, colour, pattern, size), i.e. external morphology (or eidonomy), as well as the form and structure of the internal parts like bones and organs, i.e. internal morphology (or anatomy). This is in contrast to physiology, which deals primarily with function. Morphology is a branch of life science dealing with the study of gross structure of an organism or taxon and its component parts. History The etymology of the word "morphology" is from the Ancient Greek (), meaning "form", and (), meaning "word, study, research". While the concept of form in biology, opposed to function, dates back to Aristotle (see Aristotle's biology), the field of morphology was developed by Johann Wolfgang von Goethe (1790) and independently by the German anatomist and physiologist Karl Fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phylogenetic
In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups of organisms. These relationships are determined by Computational phylogenetics, phylogenetic inference methods that focus on observed heritable traits, such as DNA sequences, protein amino acid sequences, or morphology. The result of such an analysis is a phylogenetic tree—a diagram containing a hypothesis of relationships that reflects the evolutionary history of a group of organisms. The tips of a phylogenetic tree can be living taxa or fossils, and represent the "end" or the present time in an evolutionary lineage. A phylogenetic diagram can be rooted or unrooted. A rooted tree diagram indicates the hypothetical common ancestor of the tree. An unrooted tree diagram (a network) makes no assumption about the ancestral line, and does ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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