Use of type specimens Type (biology)

1 use of type specimens

1.1 holotype
1.2 paratype
1.3 allotype
1.4 neotype
1.5 syntype
1.6 lectotype
1.7 paralectotype
1.8 hapantotype
1.9 ergatotype
1.10 alternatives preserved specimens
1.11 formalisation of type system

use of type specimens

type illustration of mormopterus acetabulosus

although in reality biologists may examine many specimens (when available) of new taxon before writing official published species description, nonetheless, under formal rules naming species (the international code of zoological nomenclature), single type must designated, part of published description.

a type description must include diagnosis (typically, discussion of similarities , differences closely related species), , indication of type specimen or specimens deposited examination. geographical location type specimen found known type locality. in case of parasites, term type host (or symbiotype) used indicate host organism type specimen obtained.

zoological collections maintained universities , museums. ensuring types kept in condition , made available examination taxonomists 2 important functions of such collections. and, while there 1 holotype designated, there can other type specimens, following of formally defined:

holotype

when single specimen designated in original description, specimen known holotype of species. holotype typically placed in major museum, or similar well-known public collection, freely available later examination other biologists.

paratype

when original description designated holotype, there may still additional specimens listed in type series , termed paratypes. these not name-bearing types.

allotype

an allotype specimen of opposite sex holotype, designated among paratypes. formerly used specimen shows features not seen in holotype of fossil. term not regulated iczn.

neotype

a neotype specimen later selected serve single type specimen when original holotype has been lost or destroyed or original author never cited specimen.

syntype

a syntype 1 of 2 or more specimens listed in species description no holotype designated; historically, syntypes explicitly designated such, , under present iczn requirement, modern attempts publish species description based on syntypes frowned upon practicing taxonomists, , gradually being replaced lectotypes. still exist still considered name-bearing types.

lectotype

a lectotype specimen later selected serve single type specimen species described set of syntypes. in zoology, lectotype kind of name-bearing type. when species described on basis of name-bearing type consisting of multiple specimens, 1 of may designated lectotype. having single name-bearing type reduces potential confusion, considering not uncommon series of syntypes contain specimens of more 1 species.

a notable example carl linnaeus lectotype species homo sapiens.

paralectotype

a paralectotype additional specimen among set of syntypes, after lectotype has been designated among them. these not name-bearing types.

hapantotype

a special case in protistans type consists of 2 or more specimens of directly related individuals representing distinct stages in life cycle ; these collectively treated single entity, , lectotypes cannot designated among them.

ergatotype

an ergatotype specimen selected represent worker member in hymenopterans have polymorphic castes.

alternatives preserved specimens

type illustrations have been used zoologists, in case of réunion parakeet, known historical illustrations , descriptions.

recently, species have been described type specimen released alive wild, such bulo burti boubou (a bushshrike), described laniarius liberatus, in species description included dna sequences blood , feather samples. assuming there no future question status of such species, absence of type specimen not invalidate name, may necessary in future designate neotype such taxon, should questions arise. however, in case of bushshrike, ornithologists have argued specimen rare , hitherto unknown color morph of long-known species, using available blood , feather samples. while there still debate on need deposit actual killed individuals type specimens, can observed given proper vouchering , storage, tissue samples can valuable should disputes validity of species arise.

formalisation of type system

the various types listed above necessary because many species described 1 or 2 centuries ago, when single type specimen, holotype, not designated. also, types not preserved, , intervening events such wars , fires have resulted in destruction of original type material. validity of species name rests upon availability of original type specimens; or, if type cannot found, or 1 has never existed, upon clarity of description.

the iczn has existed since 1961, when first edition of code published. iczn not demand type specimen historical validity of species, , many type-less species exist. current edition of code, article 75.3, prohibits designation of neotype unless there exceptional need clarifying taxonomic status of species (article 75.2).

there many other permutations , variations on terms using suffix -type (e.g., allotype, cotype, topotype, generitype, isotype, isoneotype, isolectotype, etc.) these not formally regulated code, , great many obsolete and/or idiosyncratic. however, of these categories can potentially apply genuine type specimens, such neotype; e.g., isotypic/topotypic specimens preferred other specimens, when available @ time neotype chosen (because same time and/or place original type).

the term fixation used code declaration of name-bearing type, whether original or subsequent designation.