The document discusses the International Code of Zoological Nomenclature (ICZN) which provides rules for formally naming animal species. It is published by the International Commission on Zoological Nomenclature and aims to ensure every animal has a unique and universally accepted scientific name. The ICZN has six main principles including binomial nomenclature, priority, coordination, and typification to determine the correct scientific name of animal taxa. It also outlines how names are structured at different taxonomic ranks from species to orders.

1. GOPIKA V NAIR
1ST MSc ZOOLOGY
MAHATMA GANDHI COLLEGE,
THIRUVANANTHAPURAM

2. 
 Widely accepted convention of zoology that rules the formal
scientific naming of animals.
 Also known as ICZN Code.
 Published by International Commission on Zoological
Nomenclature [ICZN] takes its power from International Union
of Biological Sciences [IUBS].
 Ensures that every animal has a unique & universally accepted
scientific name.
WHAT IS ICZN?

3. 
 System of rules & recommendations
 Fundamental Goal : provide maximum continuity in the
naming of all animals with
 Uniqueness
 Universality &
 Stability
 Guide only the nomenclature of animals, leaves zoologist the
freedom in classifying new taxa.
WHAT IS ICZN?

4. 
 First introduced by a British ornithologist, zoologist &
palaeontologist Hugh E. Strickland, conceived a code for
introducing uniformity in international nomenclature it was
modified & evolved to the present systems
 1st edition - 1961
 4th edition – 1999
 ICZN is independent from other nomenclature systems like
Botanical nomenclature (ICBN).
 E.g. :
 Fig Shell (Gastropod animal) & Fig Tree (Plant)
 Genus Abronia in both plants & animals
BRIEF HISTORY

5. 
 Consist of 3 main parts :
 The Code Proper
 Includes ‘Preamble’ followed by 90 consecutively numbered
‘Article’ grouped in 18 chapters.
 Appendices
 3 appendices, first 2 having status of recommendations & 3rd is the
constitution of the Commission.
 Glossary
 Terms used in the text are clearly defined in the ‘Glossary’.
PARTS OF ICZN

6. 
 The rules principally regulate :
 How names are correctly established in the frame of
binomial nomenclature.
 Which name must be used in case of name conflicts.
 How scientific literature must cite names.
PRINCIPLES OF ICZN

7. 
 There are six basic principles :
1) Principle of binomial nomenclature.
2) Principle of priority.
3) Principle of co-ordination.
4) Principle of the first reviser.
5) Principle of homonymy.
6) Principle of typification.
PRINCIPLES OF ICZN

8. 
1) PRINCIPLE OF BINOMIAL NOMENCLATURE
 Name of species is composed of a combination of two name
(Binomen).
 Generic name
 Specific Epithet
E.g. Homo sapiens
 Rules for Binomial Nomenclature
 Names must either be Latin or Latinised.
 1st letter of genus name - capital
 1st letter of species name – small
 While typing – names italicized.
 When written with free hands – names separately underlined.
PRINCIPLES OF ICZN

9. 
2) PRINCIPLE OF PRIORITY
 First formulated in 1842
 Correct formal scientific name for an animal taxon is the oldest
available valid name.
 1815 George Ord named a species of Pronghorn – Antilocapra americana
 1855 John Edward Gray published same species – Antilocapra anteflexa
 Here, based on Principle of priority the name Antilocapra americana
takes priority & Antilocapra anteflexa becomes a junior synonym.
PRINCIPLES OF ICZN

10. 
3) PRINCIPLE OF CO-ORDINATION
 Publishing a new zoological name automatically & simultaneously
establishes all corresponding names in the relevant other ranks
with the same type.
 E.g. 1 – Publishing a species name (binomen) – Homo sapiens also
establishes the sub-species name (trinomen) – Homo sapiens sapiens
 E.g. 2 – Publishing a family name – Giraffidae also establishes the
super-family name – Giraffoidea & the sub-family name -
Giraffinae
PRINCIPLES OF ICZN

11. 
4) PRINCIPLE OF THE FIRST REVISER
 Supplements the Principle of Priority
 Deals with situations that cannot be resolved by priority
 Two or more different names for same taxon –
 In 1758 Linnaeus established Strix scandiaca & Strix noctua as two
different species of Aves.
 Both taxa later turned out a same species, the Snowy owl.
 In 1931 Lonnberg acted as first reviser & selected Strix scandiaca to
have precedence.
PRINCIPLES OF ICZN

12. 
5) PRINCIPLE OF HOMONYMY
 The name of each taxon must be unique.
 A name that is a homonym of another name must not be used as a
valid name.
 E.g. – In 1773 Drury established Cerambyx maculatus (Coleoptera) for a
species from Jamaica. In 1775 Fueblin established Cerambyx maculatus
for a different species from Switzerland.
 Principle of Priority apply here and Drury’s name gets precedence &
Fueblin’s name becomes homonym.
PRINCIPLES OF ICZN

13. 
6) PRINCIPLE OF TYPIFICATION
 Any family group name must have a type genus.
 Any genus group name must have a type species.
 Any species group name can (not must) have one or more type
specimens usually deposited in a museum collection.
PRINCIPLES OF ICZN

14. 
 UNINOMIAL NOMENCLATURE
 From subgenera & above
 Utilize a single word
 Plural nouns for names above genus & singular nouns for genus &
subgenus
 Written with initial capital letter.
 Zoological code stipulates standard endings for the names of
 Superfamily (-oidea) – hominoidea
 Family (-idae) – hominidae
 Subfamily (-inae) – hominae
 Tribe (-ini)
 Rarely Subtribe (-ina)
UNINOMIAL & TRINOMIAL
NOMENCLATURE

15. 
 TRINOMIAL NOMENCLATURE
 Used when species further subdivided
 Extends the standard system of binomial nomenclature by adding a third
epithet
 E.g. – Columbia livia domestica (domestic pigeon), Homo sapiens sapiens
 In botany, species further divided into any of subspecies, variety, sub
variety/form whereas in zoology usually subdivided into subspecies level
only. Trinomial name usually includes a qualifier.
 E.g. – Astrophytum myriostigma subvar.glabrum (where ‘subvar’ is the qualifier)
UNINOMIAL & TRINOMIAL
NOMENCLATURE