Taxonomy MarBEF/IODE training workshop Oostende, March 2007

Taxonomy  Science concerned with Nomenclature: give ‘scientific’ names to species Strictly regulated, different ‘codes’ for botany, zoology, bacteria Classification: create and name groups, ‘taxa’  ‘Systematics’ is often used as an equivalent

Scientific names  In principle, Latin or Latinised names  Regulated by the codes: Codes are drafted and maintained by Commissions International Code for Zoological Nomenclature International Code for Botanical Nomenclature International Code for Bacterial Nomenclature Commissions are arbiter in case of disputes  Problem: many unicellular organisms are neither plants nor animals, have two names

Classification  1,700,000 names! We need a system to organise this information Hierarchical classification  Classification is based on phylogeny (common descent) Hypothesis: life only originated once; all organisms descend from a single ancestor Basis of objectivity in classification

Hierarchy: common descent Animalia ArthropodaEchinodermata CrinoideaHolothuroideaAsteroideaOphiuroideaEchinoidea Chordata…

Hierarchy: sub-sets Biota Animalia Arthropoda Crustacea … Echinodermata Fungi … … Plantae … … … …

Hierarchy: ranks Regnum: Animalia, Plantae… Phylum: Arthropoda, Echinodermata… Classis: Crustacea, Insecta… Ordo: Decapoda, Amphipoda, Isopoda… Familia: Xanthidae, Diogenidae… Genus: Xantho, Progeryon… Species: Xantho granulicarpus, Xantho hydrophilus…

Extra ranks  ‘Super-’, ‘Sub-’, ‘Infra-’ Subordo, infraordo, superfamilia… Not for genus and species (except subspecies)  Tribus: between family and genus  Infraspecific Subspecies only rank recognised in zoology Botany: varietas, forma  Botany: ‘Divisio’ instead of ‘Phylum’

Standard endings RankBotanyBacteriologyZoology Divisio(-phyta/-mycota) Subdivisio(-phytina/-mycotina) Classis(-phyceae/-mycetes/-opsida) Subclassis (-phycidae/-mycetidae/-idae) Ordo-ales-ales Subordo-ineae-ineae Superfamilia(-oidea) Familia-aceae-aceae-idae Subfamilia-oideae-oideae-inae Tribus-eae-eae(-ini) Subtribus-inae-inae

Uni-, bi- et multinomens  Names of rank of genus and above consist of a single part E.g. ‘Hominidae’, ‘Homo’  Names of rank species and below consist of several parts E.g. ‘Homo sapiens’  Subspecies… indicated with extra parts E.g. ‘Homo sapiens erectus’  Several name parts, one name

Format of taxonomic names  Names of genera and lower are often written in italics E.g. ‘Homo’ and ‘Homo sapiens’  Subgenus is written between brackets between genus and specific epitheton Holothuria (Thymiosicya) impatiens  Subgenus and above are written with initial capital  Genus name often abbreviated to first character at subsequent mentions E.g. H. sapiens

Specific epitheton  Second part of species name  Is often an adjective Takes gender from the genus name (which is always a noun)  Can be other than adjective Noun in apposition Locality Named after a person genitive

Classification can change  Phylogeny = scientific study, Research results can alter understanding Interpretation of facts can be different between scientists  Difficult to construct a complete and consistent classification  Can result in name changes Species moves from one genus to another… Epitheton changes when genus has other gender

Nomenclature  Publication To be valid, name has to be published in a publication acceptable to the code  Name has to be unique within the domain of the code Zoological name can be same as botanical  Typification Name has to be supported by a type

Publication  Names have to be published to be valid Rules for validity are part of the code No thesis, nor WWW! Date of publication determines seniority of the name Important in case of dispute  Start of the nomenclature: Zoology: Linnaeus (1758). Systema naturae… 10 th ed. Botany: Linnaeus (1753). Species plantarum. 1 st ed.

Authority  Author of the publ ication that contains the description becomes ‘author’ of the taxon name  Date of description is the date that the publication became publicly available Not necessarily the same as the date on the cover of the publication Journals have a tendency to be published late Differences in calendars (e.g. Russia in the beginning of the 20 th century)

Authority  Authority is very important in taxonomy, often added to the name For many journals mandatory for taxa of rank genus and below E.g. Homo sapiens Linnaeus, 1758 Zoology: with year of publication E.g. Zostera noltii Hornemann Botany: without year

Names are unique…  … but not absolutely so Botanical name can be same as zoological There is no central register (yet), so this leaves a lot of scope for mistakes ‘Preoccupied name’  Has to be replaced with another name – ‘replacement name’

Name changes  If a species is transferred from one genus to another, the species’ name changes  Zoology: the original author’s name is placed between brackets Spongia aurea Montagu, 1818 Hymeniacidon aurea (Montagu, 1818)  Botany: parentheses + author of the new ‘combination’ Halophila stipulacea (Forsskål) Ascherson

Name changes  Specific epitheton is often adjective, has to be declined according to rules of latin grammar Turbo littoreus Linnaeus, 1758 Littorina littorea (Linnaeus, 1758)  Specific epitheton can be noun, which has its own gender Tellina (Moerella) pygmaeus Lovén, 1846 Taxonomists, but especially other users of taxonomic names, are often mistaken! Tellina pygmaea: wrong!!

Typification  Type serves as an anchor, to stabilise taxonomy  Type of a species: specimen  Zoology Type of a genus: species Type of a family: genus  Botany: type is always a specimen

Synonyms  Objective synonyms Preoccupied name… Objective synonyms have the same type  Subjective synonyms An author has described a taxon, but a subsequent author has stated that the specimens of that species actually belong to a taxon that has been described before

Interpretation of the literature  Difference between misidentifications and synonyms not always clear List of names below a taxonomic name in a taxonomic revision often contain both!  Different authors use different classifications  Importance of having an intelligent database, that aids in interpreting names Has to have information on synonyms, spelling variations…

Types of tax info systems  ‘Nomenclators’: list of names  Taxonomic List of names, plus taxonomic information (author, reference for description publication…) Who’s valid??  Species database Information on biology, identification…  Distribution For a group of species or for a region

Nomenclators  Index Fungorum  Animals Nomenclator Zoologicus (genus level) Index Animalium  Plants International Plant Names Index

Taxonomic databases  Global Integrated Taxonomic Information System (ITIS) Species 2000 Systema Naturae 2000 UNESCO Register of Marine Organisms  Regional Species 2000 Europe, European Register of Marine Species (ERMS) Marine Species Database for Eastern Africa (MASDEA)  Taxonomic Fungi…

Biogeographical DBs  Global Biodiversity Information Facility (GBIF)  OBIS And its regional nodes  Taxonomic names are not always integrated

Species databases  FishBase  Hexacorallia, Algaebase, CephBase, Brachnet, NeMys…   Tree of Life project