Information AboutHolotype |
| CATEGORIES ABOUT HOLOTYPE | |
| zoological nomenclature | |
| botanical nomenclature | |
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For example, the holotype for the Butterfly ''Lycaeides idas longinus'' is held by the Museum of Comparative Zoology at Harvard University , and the holotype for the extinct Mammal Cimolodon is at the University Of Alberta . A holotype is not necessarily "typical" of that taxon, although ideally it should be. Sometimes just a fragment of an organism is the holotype, for example in the case of a rare Fossil . The holotype of ''Pelorosausus humerocristatus'', a large Herbivore Dinosaur from the early Jurassic period, is a fossil leg bone stored at the Natural History Museum in London . Even if a better specimen is subsequently found, the holotype is not superseded. In the absence of a holotype (e.g. it was lost) another type may be selected, out of a range of different kinds of type, depending on the case. A type is what fixes a name to a taxon. Note that in the ''ICBN'' and ''ICZN'' the definitions of types are similar but not identical. For example in both the ''ICBN'' and the ''ICZN'' a "neotype" is a type that was later appointed in the absence of original material. Additionally, under the ''ICZN'' the Commission is empowered to replace a holotype with a "neotype", when the holotype turns out to lack important diagnostic features needed to distinguish the species from its close relatives. For example, the crocodile-like Archosaur ian reptile ''Parasuchus hislopi'' Lydekker , 1885 was described based on a pre Maxilla ry Rostrum (part of the snout), but this is no longer sufficient to distinguish ''Parasuchus'' from its close relatives. This made the name ''Parasuchus hislopi'' a nomen dubium. Texan paleontologist Sankar Chatterjee proposed that a new type specimen, a complete skeleton, be designated. The International Commission On Zoological Nomenclature considered the case and agreed to replace the original type specimen with the proposed neotype.. Under the ''ICBN'', also, a replacement type could be appointed by such a procedure, but this would be called a "conserved type". However a conserved type would not be appointed in the case of a type that is insufficiently clear: in that case an additional and clarifying type could be designated, a so-called "epitype". Great care must be used in speaking of types, as definitions are very precise. REFERENCES |
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