4.(c) Write down the salient features of zoological nomenclature.

The International Code of Zoological Nomenclature (ICZN) outlines a comprehensive set of rules and recommendations designed to promote stability, universality, and uniqueness in the scientific naming of animals. These rules are crucial for maintaining order in taxonomy and ensuring consistent identification across the global scientific community. The salient features are built upon several fundamental principles and specific naming conventions.

Fundamental Principles of Zoological Nomenclature

• Principle of Binomial Nomenclature: This is a cornerstone of the system, stating that the scientific name of a species must consist of two parts: a generic name and a specific name. For example, Homo sapiens. This principle ensures uniqueness, as the combination of two names makes the species name distinct. For subspecies, a trinomen (three names) is used.
• Principle of Priority: This is the most important principle for stability. It dictates that the valid name for an animal taxon is the oldest available name that applies to it. If multiple names have been published for the same taxon, the earliest published valid name takes precedence. The starting date for zoological nomenclature under the Code is January 1, 1758, coinciding with the 10th edition of Linnaeus's Systema Naturae.
• Principle of Homonymy: This principle asserts that the name of each taxon must be unique. A name that is a junior homonym (identical spelling to an earlier established name) must not be used as a valid name within the same group (family-group, genus-group, or species-group). This prevents identical names from being applied to different taxa, thus avoiding confusion.
• Principle of Typification: Every nominal taxon in the family-group, genus-group, and species-group must have a name-bearing type (e.g., holotype, type species, type genus). This "type" physically anchors the name to a specimen or a lower-ranked taxon, ensuring that the application of the name is unambiguous and objective.
• Principle of Coordination: When a new zoological name is published, it automatically establishes corresponding names in relevant ranks. For example, the publication of a new species name automatically creates the genus name, and vice versa, if not already existing, within the same family group.
• Principle of the First Reviser: In cases where two or more names or acts of nomenclature simultaneously appear, or where there is ambiguity, the first subsequent author (the "First Reviser") to cite them and choose one over the other establishes the precedence.

Specific Rules and Conventions

• Language and Format: Scientific names must be either Latin or Latinized. They are typically written in italics, with the generic name capitalized and the specific name in lowercase (e.g., Panthera tigris). When handwritten, they should be underlined.
• Ranks of Names:
  • Names of taxa higher than species (e.g., family, order, class) are uninominal (single name) and are not italicized.
  • A species name is a binomen (e.g., Apis mellifera).
  • A subspecies name is a trinomen (e.g., Canis lupus familiaris for the domestic dog).
  • A subgenus name is placed in parenthesis between the genus and species names, e.g., Xorides (Gonophonus) nigrus.
• Endings for Higher Taxa: Family names typically end in "-idae" (e.g., Felidae), and subfamily names end in "-inae" (e.g., Felinae).
• Gender Agreement: The specific name, if an adjective, must agree in gender with the generic name (e.g., Drosophila obscura).
• Independence of Codes: Zoological nomenclature operates independently of other codes of nomenclature, such as botanical nomenclature. This means a generic name can be the same for an animal and a plant (e.g., Ficus for a genus of fig trees and a genus of fig shells).
• Author Citation: The author's name (the person who first described the species) and the year of publication can be appended to the scientific name, but it is not formally part of the name and its use is optional (e.g., Cancer pagurus Linnaeus, 1758).
• Synonymy and Homonymy: The Code provides rules for dealing with synonyms (different names for the same taxon) and homonyms (identical names for different taxa), prioritizing the oldest valid name and rejecting junior homonyms.

These features collectively ensure that the naming system is robust, unambiguous, and capable of accommodating the discovery of new species and reclassification of existing ones while maintaining historical accuracy and stability.