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Type species

In biological nomenclature, a is the nominal species designated as the name-bearing type for a genus or subgenus, serving as the permanent reference point that anchors the genus name to a specific taxon and ensures nomenclatural stability. This concept is fundamental to the International Code of Zoological Nomenclature (ICZN), where the type species is typically one of the originally included species in the genus description, fixed either by monotypy (when only one species is included), by explicit original designation, or by later fixation if not originally specified. For example, if a genus is established with multiple species but no type designated, the type species can be selected subsequently from those originally included to resolve ambiguity. The role of the type species extends beyond to other domains of biological , including an analogous provision in the International Code of for algae, fungi, and plants (ICN), where the type of a name is specified as a species (referred to as the type species) within that genus, ensuring consistent application of names across revisions. In practice, the type species itself has a name-bearing type specimen (such as a ), which physically links the nomenclature to observable characteristics, allowing taxonomists to evaluate whether other species belong to the same based on shared traits with this reference. This system promotes objectivity and prevents disputes by tying abstract names to concrete evidence, though misidentifications of the type species can occur and are addressed through specific ICZN provisions for correction while preserving stability. The importance of type species lies in their contribution to taxonomic reliability, as all species assigned to a must align with the diagnostic features of the type species, facilitating evolutionary studies and inventories. Without a designated type species, names risk instability, potentially leading to nomenclatural revisions by bodies like the . In modern , of type species has become crucial for resolving long-standing uncertainties, integrating molecular data with traditional to refine boundaries.

Definition and Importance

Definition

In biological , a is the nominal designated as the name-bearing type for a or , thereby permanently linking the name to that and its associated type specimen or illustration. This designation ensures that the name applies unambiguously to the encompassing the , providing a fixed reference point for taxonomic stability. The type species anchors the identity of the : if the species is later reclassified into another due to taxonomic revisions, the original name follows it, maintaining nomenclatural continuity. This mechanism plays a crucial role in stabilizing biological classification by preventing arbitrary shifts in and facilitating consistent identification across . The concept is formalized in the (ICZN) for animals, where it explicitly serves as the type for genus-group taxa, and is adapted in the International Code of Nomenclature for , fungi, and plants (ICN) for plants, fungi, and , with the type defined as the type of a specific included name.

Importance in Nomenclature

The serves as a fixed point for a name, ensuring nomenclatural stability by preventing arbitrary reassignments of to genera and facilitating the resolution of synonymy disputes through a permanent taxonomic anchor. By tying the genus name objectively to a specific nominal , it provides a concrete basis for defining boundaries, promoting consistent during taxonomic revisions and minimizing subjective interpretations across different researchers. In the absence of a designated type species, genera become untypified, leading to ambiguity in their application and potential nomenclatural instability, with many such cases persisting in zoological and complicating systematic studies. This backlog of untypified genera underscores the ongoing challenges in achieving full typification, as failure to address it can result in unresolved taxonomic uncertainties that hinder effective documentation. Beyond core , the type species contributes to international consistency in scientific naming by establishing universal standards. In contexts, this stability aids legal and frameworks by providing reliable identifiers for protected .

Designation of Type Species

Original Designation

The original designation of a type species occurs when the author of a new explicitly selects and indicates a nominal as the type in the original establishing the genus-group . This is typically done by clearly stating the binomen of the chosen species, using phrases such as "type species" or "designated as type," ensuring the fixation is unambiguous and binding for nomenclatural purposes. The designated species must be a validly published binomen included in the protologue of the genus, serving as the nomenclatural anchor to maintain stability in classification. In cases of monotypic genera, where the original publication includes only a single under the new , that species automatically becomes the type species by monotypy without requiring an explicit statement, provided it is validly included. This method implicitly fixes the type through the structure of the description itself, prioritizing the sole nominal as the representative. The practice of original designation became prevalent in the early 19th century, establishing nomenclatural stability from the outset of genus publication.

Subsequent Designation

When no type species is designated in the original publication of a genus, a subsequent author may fix one through explicit selection from the originally included nominal species, a process known as subsequent designation or lectotypification for genus-group taxa. This method ensures stability by binding the genus name to a specific species, and the first valid such designation by a subsequent author is definitive, rendering later attempts invalid. Under the International Code of Zoological Nomenclature (ICZN), this applies primarily to genera established before 1931, as later ones require original fixation, though exceptions exist for certain ichnotaxa. Another mechanism is fixation by subsequent monotypy, where, after the genus's establishment, only one nominal remains included, automatically becoming the type without explicit statement. However, fixation by elimination—transferring all but one originally included out of the genus—does not constitute valid designation. Eligible for fixation include those originally cited, even if under incorrect spellings, synonyms, replacement names, or misidentifications, provided the intent links to an original element. In botanical nomenclature, analogous lectotypification occurs under the International Code of Nomenclature for , fungi, and (ICN), selecting a type from original material to resolve ambiguity. For cases of lost, destroyed, or highly ambiguous type material leading to nomenclatural instability, a neotype-like replacement for the type species may be proposed, but this requires approval by the using its plenary powers, rather than routine designation. Such actions address challenges like , where a junior homonym genus necessitates a new name with potential refixation of the type species, or , where fixing a junior synonym binds the genus to its senior equivalent. Procedures for all subsequent designations mandate explicit statement of the fixation, publication in a or work that permanently records nomenclatural acts, and inclusion of a rationale justifying the choice, often prioritizing species with well-preserved types or nomenclatural . Conditions for conservation, such as prevailing usage, may also apply to maintain established .

Application in Zoology

Rules under ICZN

The (ICZN), in its Fourth Edition effective from 1 January 2000, establishes a comprehensive framework for the fixation and designation of type species to ensure stability and universality in . Article 42 specifically governs the type species for genus-group nominal taxa, mandating that every such name published after 31 December 1930 must have a type species fixed either by original designation or subsequently. The type species serves as the name-bearing type for the or , providing an objective standard for the application of the name, and it must be a nominal originally included in the . Exceptions apply to collective groups of species, which lack type species, and to pre-1931 names that may remain unfixed unless subsequently designated. Valid designation of a type species requires in a work that meets the criteria of Article 8, including issuance for permanent public scientific record in numerous identical copies, with explicit indication of the new name and its type fixation under Articles 11 and 16. For original designations, the author must explicitly state the type species in the establishing the genus-group name. Subsequent designations, such as lectotype selection under Article 67, occur when no type was originally fixed or when the original series is ambiguous; a lectotype must be designated from syntypes with an express statement of intent and purpose, and the first reviser to do so validly prevails. Neotypes, addressed in Article 75, may be designated to replace lost, destroyed, or inadequately defined original types when there is an exceptional need for stability and the neotype conforms to the original type locality and description; however, if a presumed lost original type is later rediscovered and causes confusion, approval is required to maintain the neotype. When citing a type species, the original binomen must be used, including authorship and date, even if it is now considered a of another species; for instance, the type species of the genus Weber, 1795, is cited as Astacus marinus Fabricius, 1775, despite being a of (Linnaeus, 1758). This obligation ensures traceability to the original description and maintains nomenclatural continuity under Articles 50 and 51. Under the Principle of Typification (Article 61), the name of a genus-group is permanently attached to its , such that any taxonomic revision or reclassification of the automatically determines the application and validity of the name; changes to the taxon's content do not affect this linkage. For stability, Article 23.9 allows reversal of precedence: a junior synonym or may be given over a senior name if the junior has been used consistently in at least 25 works by at least 10 authors over 50 years, provided the senior name has not been used since 1899, thereby protecting prevailing usage. The Fourth Edition introduced requirements for explicit type fixation in new names post-1999 and expanded valid publication criteria to include works deposited in major libraries. A key came via Declaration 44 in 2003, which modified Article 74.7.3 to require an express statement of deliberate intent in lectotype and similar subsequent designations, enhancing clarity and preventing inadvertent fixations. No further amendments affecting type species rules have been enacted as of 2025.

Examples in Zoology

One prominent example in involves the Monacha Fitzinger, 1833, a group of terrestrial gastropods in the family Hygromiidae. The type species is Monacha cartusiana (Müller, 1774), originally described as Helix cartusiana O. F. Müller, 1774, which serves as the nomenclatural anchor for the genus. This designation, fixed by monotypy in the original publication, has ensured amid taxonomic rearrangements, as subsequent studies reclassified related snails while preserving the link to this Mediterranean species known for its cream-colored shell and habitat in dry grasslands. In , the Homarus Weber, 1795, exemplifies the persistence of type species through . The type species is Astacus marinus Fabricius, 1775, subsequently recognized as a subjective of Cancer gammarus Linnaeus, 1758, now known as Homarus gammarus (Linnaeus, 1758), the European lobster. Designated by subsequent fixation under ICZN Article 69, this original name maintains its role in defining the despite the , highlighting how type citations endure to link the nominal taxon to its historical basis in Atlantic and Mediterranean waters. Paleontological nomenclature demonstrates the type species' role in reclassification debates with the genus Osborn, 1905, typified by Osborn, 1905, based on the holotype specimen AMNH 973, a partial from Montana's . This designation influences genus stability; for example, a 2022 proposal to split T. rex fossils into three species (T. imperator, T. regina, and T. rex) argued for distinct morphologies, but the type species requirement under ICZN Article 67 would retain the name for the including the , constraining any taxonomic moves and sparking widespread debate among paleontologists. Contemporary challenges persist with untypified genera, especially in Coleoptera, where a 2023 study identified 112 untypified type genera requiring type species fixation under ICZN Articles 68–70 to resolve ambiguities in family-group , with ongoing ICZN applications addressing subsets like and Carabidae to stabilize suprageneric taxa.

Application in Botany

Rules under ICN

Under the International Code of Nomenclature for , fungi, and (ICN), the typification of genus names is primarily addressed in Article 10, which establishes that the type of a name of a or any subdivision of a is the type of the name of one of the included in it at the time of its original publication, except in cases specified by Article 10.4 where a specimen or illustration may be directly designated by conservation. This framework ties the stability of generic names to a specific nomenclatural type element—typically a specimen or illustration serving as the type of the selected —rather than emphasizing the species name itself as the fixed bearer. When citing the type, the (the original validly published name) of the is included if the name has been legitimately changed, ensuring traceability to the original description. Original designation of the type occurs through explicit indication by the author in the protologue (the original publication), such as by naming a particular species, or automatically via monotypy if the genus is described with only one species. The selected species must be one originally included in the genus, meaning it is either explicitly cited or unambiguously combinable from the protologue. For subsequent designation, when no original type is indicated, lectotypification under Article 9 is applied: a lectotype is selected from the original material associated with the species name, prioritizing elements like syntypes or illustrations that best represent the taxon as understood at the time of publication. Neotypification may be used if no original material exists, but it requires justification and is generally avoided if lectotypification is possible. In comparison to zoological nomenclature under the ICZN, the ICN framework de-emphasizes the as the primary nomenclatural anchor, instead centering on the underlying type element (specimen or illustration), and permits direct typification of genera by such elements in conserved cases without mandating a fixation. This approach accommodates the historical reliance on illustrations in botanical descriptions and allows flexibility for genera lacking formally named at establishment. Refinements in the Shenzhen Code (2018) enhanced these rules by explicitly accepting electronic publications for valid type designations and permitting digital images or descriptions of specimens as surrogates for physical types, provided the original material is clearly referenced and accessible. The subsequent Madrid Code (2025) retained these provisions with minor clarifications on data exchange for digital nomenclatural resources, including improved indexing of type specimens to facilitate global access without altering core typification procedures.

Examples in Botany

In botany, the type species serves to fix the application of a generic name under the International Code of Nomenclature for algae, fungi, and (ICN), ensuring stability amid taxonomic revisions. A prominent example is the genus L. (Rosaceae), where Rosa cinnamomea L. was conserved as the type species by the 2005 Vienna to resolve ambiguities from Linnaeus's original description, which included multiple ; this designation anchors the genus to the cinnamon rose, preventing nomenclatural disruption for over 150 of roses. Subsequent designation via lectotypification is common when original material is ambiguous or lost, as seen in the genus Poa L. (Poaceae). The type species Poa pratensis L. (Kentucky bluegrass) was lectotypified by George V. Nash in 1913, selecting a specimen from Linnaeus's material to clarify the genus's circumscription among approximately 500 grass species; this fixation resolved confusion from Linnaeus's brief diagnosis, emphasizing the ICN's provisions for stabilizing polytypic genera. In fungi, governed by the same ICN with adaptations for non-vascular organisms, the type species exemplifies kingdom-specific adjustments to nomenclature. For the genus Agaricus L. (Agaricaceae), Agaricus campestris L. (field mushroom) serves as the type, designated to retain the genus's application to edible gilled mushrooms despite Linnaeus including disparate taxa like A. muscarius L. (now Amanita muscaria (L.) Lam.); this choice highlights how typification prevents misapplication across fungal lineages, supporting over 500 species in the genus. Contemporary practices reflect technological advances under the 2018 Shenzhen Code, which permits high-resolution digital images of specimens as types if they enable unambiguous identification (Art. 9.13). In fern taxonomy, such digital typification has been applied post-2018, for instance, in lectotypifying names in the genus L. (Aspleniaceae) using scanned sheets from global collections, facilitating access for researchers studying over 700 species without physical exchange of fragile materials.

Historical Background

Origin of the Concept

The concept of the type species emerged in the early as taxonomists sought to address the instability in generic nomenclature following the explosion of species descriptions after Carl Linnaeus's establishment of in (10th edition, 1758). Linnaeus's system provided a foundation for naming but lacked a mechanism to permanently link a to a specific species, leading to frequent reassignments as new material was described. built on this in his extensive works on , such as Systema Entomologiae (1775), by classifying insects based on Linnaean species but without formal fixation of types, which contributed to ongoing nomenclatural confusion. Pierre André formalized the type species idea in his 1810 work Considérations générales sur l'ordre naturel des animaux composant les classes des crustacés, des arachnides, et des insectes, where he first employed the term "espèce type" to designate a representative as the fixed anchor for a . , a pioneering entomologist, argued that selecting such a type would prevent arbitrary shifts in generic boundaries, particularly in the classes he studied, thereby promoting objectivity in classification. This innovation directly responded to the post-Linnaean "nomenclatural chaos," where the rapid influx of new threatened the coherence of higher taxa. The concept quickly spread within specialized fields like and during the 1820s, as taxonomists recognized its utility for resolving ambiguities in generic definitions. Key early adopters included Jean Victor Audouin, who applied type designations in his 1826 descriptions of arachnids and , and , who integrated the approach in his 1820s–1830s works on mollusks and to standardize revisions amid expanding collections. Overall, the motivation behind the type species was to impose fixity and stability on , ensuring that generic names retained verifiable referents despite the accelerating pace of discoveries and taxonomic debates in the post-Linnaean era.

Evolution of the Rules

The formal codification of the type species concept in zoological began with the 1905 Règles Internationales de la Zoologique, which introduced typification as a to stabilize genus names by designating a type , building on earlier informal practices. This early code, drafted by an committee under the International Congress of Zoology, emphasized and fixity to resolve nomenclatural disputes arising from Linnaean binomials. In parallel, botanical saw its foundational rules emerge from Alphonse de Candolle's 1867 Lois de la Botanique, which laid groundwork for typification, though full awaited later congresses. The 1930 International Code of , adopted at the Fifth Botanical Congress in , explicitly incorporated type designation for genera, marking a shift toward systematic stability in . The (ICZN) evolved through successive editions, with the first modern version published in 1961, replacing provisional rules and clarifying type fixation procedures to enhance universality. This edition established core principles for type species selection, including subsequent designation when not originally specified. The fourth edition in 1999 introduced enhanced stability provisions, such as expanded plenary powers for the (ICZN) to conserve names and types in cases of instability, reflecting a response to accumulated nomenclatural conflicts. Ongoing ICZN activities, including amendments and opinions, continue to refine these rules, as seen in post-1999 declarations addressing electronic publications. Botanical rules developed concurrently through International Botanical Congresses, starting from de Candolle's 1867 framework and progressing through revisions that integrated type species more rigorously. The International Code of Nomenclature for , fungi, and (ICN) reached its current form with the 2025 Madrid Code, adopted at the Twentieth in , . This evolution paralleled zoological efforts, with the International Association for overseeing updates to promote global consistency. Key refinements across both codes shifted from rigid priority-based systems to more flexible mechanisms, such as neotype approvals, to accommodate lost or ambiguous types while preserving nomenclatural stability. In the ICZN, neotype designation under Article 75 requires exceptional need and oversight, a provision strengthened in later editions to allow evidence-based substitutions. Similarly, the ICN permits neotypes when original material is unavailable, emphasizing diagnostic utility. The digital era introduced further adaptations, including mandatory electronic registration for new names since in and provisions for digital types in , to address backlogs in typification and facilitate amid vast digitized collections. These changes underscore a commitment to balancing historical fixity with modern accessibility.

Type Specimens

Type specimens serve as the foundational nomenclatural standards in biological , providing the physical or illustrative basis for the scientific names of and, through the type species, for genera. In zoological nomenclature, they are defined as specimens belonging to the type series of a nominal species-group , with name-bearing types (such as holotypes or syntypes) fixing the application of the name. Similarly, in , a type specimen or is cited in the protologue to unambiguously apply the name to the . These specimens link directly to the type species, as the name-bearing type of the type species anchors the genus name's application. The primary types include the , which is a single specimen designated in the original publication as the name-bearer; syntypes, a series of specimens from the original material when no was designated; lectotypes, selected subsequently from the syntype series or original material to serve as the single name-bearer; and neotypes, designated to replace a lost or destroyed holotype, lectotype, or syntypes when no original material remains. In , an additional category, the epitype, may be selected to provide clearer interpretation of an existing ambiguous type. These designations ensure stability in by tying names to verifiable exemplars. Selection of type specimens requires that they adequately represent the morphological and anatomical features of the , typically chosen from well-preserved material collected during the original description. They must be deposited in recognized public institutions, such as museums or herbaria, to facilitate access for verification and study by the . For instance, holotypes are preferred when possible to avoid , and post-1999 zoological publications their explicit fixation. Type specimens are crucial for providing objective, verifiable evidence in species identification and taxonomic revisions, serving as the ultimate reference against which other specimens are compared. This role has been enhanced since the early 2000s through standards, which recommend high-resolution scans (at least 300-600 dpi), lossless formats like , and standardized (e.g., DIG35) to enable global access via like GBIF without risking physical damage. Projects such as the European Network for Information (ENBI) have established best practices for imaging, including color-managed and automontage for depth-of-field enhancement. Challenges in maintaining type specimens include physical deterioration from age, environmental factors, or improper storage, as well as outright loss due to disasters like fires or wars, which can necessitate neotypification to restore nomenclatural stability. Guidelines from the ICZN emphasize designating neotypes only when original material is irretrievably lost and under strict conditions to avoid taxonomic confusion.

Other Types of Types

In zoological nomenclature, typification extends beyond the species level to higher taxonomic ranks through the designation of type genera for family-group taxa. A family-group name, such as Felidae, is based on the stem of its type genus, Felis, which provides the nomenclatural anchor for the entire group, ensuring that changes in the genus's application do not destabilize the family name unless explicitly ruled otherwise by the International Commission on Zoological Nomenclature. Similarly, in botanical nomenclature under the International Code of Nomenclature for algae, fungi, and plants (ICN), family names like Fabaceae are formed from the genitive of a type genus such as Faba, linking the family directly to that genus for stability. For even higher ranks, such as orders, both codes establish a type family as the nomenclatural reference; for instance, the order Rosales in botany has Rosaceae as its type family, cascading the typification upward from species through genus and family. Variant types of name-bearing elements supplement primary types, particularly in cases involving multiple specimens or ambiguities. In , a is any specimen from the original type series excluding the (or syntypes), serving to corroborate the without bearing the name itself; for example, paratypes of a newly described might include additional individuals collected alongside the holotype to illustrate morphological variation. In , an epitype is a modern supplementary specimen designated to clarify or reinforce an existing holotype, lectotype, or neotype when the original material is incomplete, lost, or poorly preserved, such as designating an epitype for a historical based on to resolve identification uncertainties. These variants enhance taxonomic precision without altering the core nomenclatural type. Across disciplinary codes, typification adapts to the nature of organisms: in , the International Code of Nomenclature of Prokaryotes (ICNP) uses type strains—viable cultures deposited in recognized collections—as the nomenclatural standard for bacterial and archaeal , analogous to type specimens but suited to culturable microbes; for instance, the type strain of is ATCC 11775, which defines the and contrasts with the type species concept that fixes genera in and . This approach highlights domain-specific adaptations while maintaining the principle of a single reference point for . The interconnections among these types form a cascading that underpins nomenclatural stability: a type species fixes the application of a name, that then serves as the type for a , and the anchors higher ranks like orders, preventing arbitrary reclassification and ensuring universal reference across taxonomic levels in both zoological and botanical systems. This structure, rooted in type specimens as the foundational elements, propagates upward to maintain consistency in the Linnaean .

References

  1. [1]
    Article 70. Identification of the type species
    A natural taxon of animals (which may, or may not, have had a name applied to it). taxonomy, n. (taxonomic, a.) The theory and practice of classifying organisms ...
  2. [2]
    67.8. Type species of nominal genus-group taxa denoted by new ...
    A nominal species is only eligible to be fixed as the type species of a nominal genus or subgenus if it is an originally included nominal species.
  3. [3]
    Article 69. Type species not fixed in the original publication
    An originally included nominal species is eligible for subsequent fixation as type species even if it is the type species of another genus-group taxon.
  4. [4]
    Rules of Nomenclature with Recommendations - NCBI - NIH
    The nomenclatural type of a genus or subgenus is the type species, that is, the single species or one of the species included when the name was originally ...
  5. [5]
    Type specimens - Purdue Agriculture
    Jun 28, 2023 · A type specimen is a physical specimen, usually in a museum, that is the basis for a taxon's scientific name and is crucial for biological ...
  6. [6]
    GEOL 104 Taxonomy and Species
    Aug 5, 2025 · Each genus has a type species: all other species are assigned to the genus based on their similarity to the type species;. Linnaean taxonomy has ...
  7. [7]
    Attaching Names to Biological Species: The Use and Value of Type ...
    Jan 11, 2021 · There are various kinds of type specimens, such as holotype, paratype, syntype, lectotype, neotype, and hapanotype. The value and status of such ...Nomenclatural Types · The Type Method · Diagnosing SpeciesMissing: nomenclature - - | Show results with:nomenclature - -<|control11|><|separator|>
  8. [8]
    Article 10
    ### Summary of Definitions and Provisions Related to Type Species or Nomenclatural Types for Genera in the ICN (Article 10)
  9. [9]
    Pierre-André Latreille | Insect Taxonomy, Arthropod ... - Britannica
    Oct 23, 2025 · He was responsible for the first detailed classification of crustaceans and insects. Quick Facts. Born: Nov. 29, 1762, Brive- ...Missing: 1810 | Show results with:1810
  10. [10]
    61.2. Name-bearing types of nominotypical taxa
    Objectivity provided by typification is continuous through the hierarchy of names. It extends in ascending order from the species group to the family group.<|control11|><|separator|>
  11. [11]
  12. [12]
    Article 68. Type species fixed in the original publication
    If a species is qualified for fixation as the type species in more than one of the ways provided for in this Article, only the valid fixation need be cited.Missing: 1810 | Show results with:1810
  13. [13]
    Type species of genera in zoological nomenclature | Bionomina
    Jun 8, 2022 · Abstract. A basic concept of zoological nomenclature is that of onomatophore, called 'name-bearing type' in the Code.
  14. [14]
  15. [15]
    International Code of Zoological Nomenclature
    Names proposed or used for collective groups are treated as genus-group names but special provisions apply to them (see Article 42.2.1). ... A taxon or assemblage ...
  16. [16]
    Article 42. The genus group
    The genus group, which is next below the family group and next above the species group in the hierarchy of classification, encompasses all nominal taxa.
  17. [17]
    Article 8 - International Code of Zoological Nomenclature
    ... Article 23.9.2 does not take precedence over a younger synonym or homonym in ... precedence under Article 24.2) can be made available. [amendment] 8.8 ...
  18. [18]
    74.5. Lectotype designations before 2000
    A lectotype may be designated from syntypes to become the unique bearer of the name of a nominal species-group taxon and the standard for its application.
  19. [19]
    Article 75. Neotypes - International Code of Zoological Nomenclature
    A neotype is the name-bearing type of a nominal species-group taxon designated under conditions specified in this Article when no name-bearing type specimen
  20. [20]
    [PDF] International Code of Zoological Nomenclature - Bio-Nica.info
    For species and subspecies this name-bearing type is either a single specimen or a number of specimens that together constitute the name-bearer; for genera and ...
  21. [21]
    Article 51. Citation of names of authors
    The name of an author follows the name of the taxon without any intervening mark of punctuation, except in changed combinations as provided in Article 51.3.Missing: Astacus marinus<|control11|><|separator|>
  22. [22]
    Article 23. Principle of priority
    The valid name of a taxon is the oldest available name applied to it, unless that name has been invalidated or another name is given precedence.
  23. [23]
    Declaration 44 – Amendment of Article 74.7.3
    Declaration 44 was published in 2003, BZN 60(4): 263 and may be accessed via the BHL. ICZN is supported by the Lee Kong Chian Natural History Museum ...
  24. [24]
    Monacha cartusiana (O. F. Müller, 1774) - MolluscaBase
    Monacha cartusiana (O. F. Müller, 1774) ; Status. accepted ; Rank. Species ; Parent. Monacha Fitzinger, 1833 ; Original name. Helix cartusiana O. F. Müller, 1774.
  25. [25]
    Homarus gammarus (Linnaeus, 1758) - WoRMS
    Sep 2, 2020 · Homarus gammarus (Linnaeus, 1758) ; Astacus europeus Couch, 1837 · junior subjective synonym ; Astacus marinus Fabricius, 1775 · junior subjective ...
  26. [26]
  27. [27]
    They Want to Break T. Rex Into 3 Species. Paleontologists Aren't ...
    Feb 28, 2022 · Three researchers argue that the animal we currently call Tyrannosaurus rex should actually be split into three separate species.
  28. [28]
  29. [29]
    10 - International Code of Nomenclature for algae, fungi, and plants
    Article 10. 10.1. The type of a name of a genus or of any subdivision of a genus is the type of a name of a species (except as provided by Art. 10.4).
  30. [30]
    The International Code of Nomenclature for algae, fungi, and plants
    The International Code of Nomenclature for algae, fungi, and plants, known as “the Code,” is the set of internationally agreed rules and recommendations that ...
  31. [31]
    International Code of Nomenclature for algae, fungi, and plants
    ### Summary of Article 9: Rules for Lectotypification and Application to Genera and Species
  32. [32]
    The importance of type species and their correct identification: A key ...
    Jul 9, 2021 · We first outline the main principles of typification and neotypification. We then discuss a critical case, using a current example from the marine planktonic ...
  33. [33]
    Shenzhen Code (2018)
    HTML-edition of the 2018 Shenzhen Code, with changes with the previous Code marked, hyperlinked with the 2012 Code.
  34. [34]
    The Madrid Nomenclature Section: outcomes and important ...
    Jul 14, 2025 · (2025). The Madrid Nomenclature Section: outcomes and important changes to the Code following the XXth International Botanical Congress.
  35. [35]
    Rosa | International Plant Names Index
    Jarvis's (Taxon 41: 568. 1992) proposal to conserve the genus name Rosa with R. cinnamomea L. as the type species was approved at the July 2005 Vienna Congress.
  36. [36]
    Poa - FNA - Flora of North America
    Aug 21, 2024 · Poa includes about 500 species. It grows throughout the world, principally in temperate and boreal regions. Sixty-one species and five hybrid ...
  37. [37]
    [PDF] A review of genus Agaricus in tropical and humid subtropical ...
    Jul 26, 2016 · Agaricus is a genus of saprobic mushrooms that includes economically important species such as A. bisporus, the button mushroom (Savoie et al. ...
  38. [38]
  39. [39]
    John Edward Gray (1800–1875): his malacological publications and ...
    Feb 29, 2012 · The type species of five genus-group names introducd by Gray are fixed under Article 70.3.2: Euthria, Pirenella,Pusionella, Rissoella, and ...
  40. [40]
    [PDF] The International Code of Zoological Nomenclature must be ...
    Feb 18, 2011 · The Code provides precise Rules for this subsequent restriction, both in the species-series (Art. 74) and in the genus-series (Art. 69).
  41. [41]
    [PDF] BULLETIN OF ZOOLOGICAL NOMENCLATURE Volume ... - Biotaxa
    Jun 30, 2009 · As stated in Article 70 of the Code of Zoological Nomenclature, when a type species is misidentified the case is to be referred to the ...
  42. [42]
    International Code of Nomenclature for algae, fungi, and plants
    Jul 21, 2025 · The International Code of Nomenclature for algae, fungi, and plants is the set of internationally agreed rules and recommendations that ...Missing: type | Show results with:type
  43. [43]
    Brief history of the Code
    The Code's history started in 1867, divided into French (1906-1935), Dutch (ca. 1950-1983), and English-only (ca. 1988 onwards) periods.
  44. [44]
    International Code of Zoological Nomenclature: Fourth Edition
    Aug 1, 2000 · —The much awaited fourth edition of the International Code of Zoological Nomenclature (called the “Code” hereafter) was issued in August 1999, ...
  45. [45]
    The Code Online | International Commission on Zoological ...
    Article 10. Provisions ... Nominal species that are already type species · 67.12. Type species of nominal genera and subgenera first denoted by synonyms ...
  46. [46]
    International Code of Nomenclature for algae, fungi, and plants
    The International Code of Nomenclature for algae, fungi, and plants is the set of rules and recommendations that govern the scientific naming of all organisms
  47. [47]
    Zoological nomenclature in the digital era - PMC - PubMed Central
    Feb 4, 2013 · Creation and use of the scientific names of animals are ruled by the International Code of Zoological Nomenclature.Missing: typification | Show results with:typification
  48. [48]
    [PDF] Challenges for the future of taxonomy - Biotaxa
    Jan 31, 2020 · Metadata from museum collections are being databased all over the world and are accessible via the Global Biodiversity Information Facility ( ...Missing: era | Show results with:era
  49. [49]
    Article 29. Family-group names
    Names in the genus and species groups which have endings identical with those of the suffixes of family-group names are not affected by this Article. Examples.
  50. [50]
    Article 65. Identification of the type genus
    In zoological works genus-group names are often abbreviated to one or two letters; such abbreviations should always be followed by a full stop (period), and ...Missing: untypified | Show results with:untypified
  51. [51]
    Article 72. General provisions
    Holotypes, syntypes, lectotypes and neotypes are the bearers of the scientific names of all nominal species-group taxa (and indirectly of all animal taxa).