(Translations may not be accurate.)

Glossary of Scientific Terms Used on AmphibiaWeb

Amphibians: A group of vertebrates including frogs, salamanders and caecilians. Amphibians usually have aquatic larvae and terrestrial adults. Read more.

Advertisement Calls: Calls used by frogs to define their territories and to attract female frogs during breeding season.

Aggressive Calls: Males usually make these calls, when other males are trying to occupy their territory or are very close to their territory.

Amplexus: Sexual embrace of amphibians; the grasping of the female's body by the male's forelimbs from a dorsal position. The grip is strong, and is not released until oviposition is completed. There are two principal types: axillary (pectoral), in which the grip is just behind the forelimbs, and inguinal (pelvic), with the grip just before the hindlimbs.

Barbels: A fleshy, tubular extension of the skin, usually on the head or the neck, which appear to be sensory, probable tactile in function.

Brumation: Time period when frogs and other ectotherms become inactive in they hide in a leaf litter or take refuge in ponds to cope with the cold, dry and harsh temperatures.

Brachial: Pertaining to or located on the upper or the humeral part of the forelimb.

Call: The noise, cry, whistle or song of an anuran, usually confined to males. In a very few species, the female has a voice.

Courtship Calls: Calls that are given by both males and females just before amplexus.

Cloaca: The common chamber into which the intestinal, urinary and reproductive duct discharge their contents, opening to the outside through the anus.

Choana: Internal opening of the nasal passage in the roof of the mouth (plural: choanae).

Defensive calls: The adults of both sexes and juveniles make these calls when startled or attacked by the potential predator.

Eclosion: The emerging of an insect from the pupa case or the emergence of larva from the egg.

Guttural Resonator: Referring to the sound coming out of throat; harsh sound.

Holotype: The specimen that is the legal bearer of the name of the species, according to the International Code of Zoological Nomenclature.

Interorbital: The measurement between the eyes, usually taken across the top of the head.

Larva: An embryo which becomes self-sustaining and independent before it has acquired the characteristic features of its parents. In frogs, may also be known as tadpole.

Labia: Lip-like structure.

Labial Tooth Row Formula (or LTRF): The formula describes the dentition of tadpoles and is written as a fraction designating the location and number of labial tooth rows. See this detailed description of the tooth rows and the formula.

Lissamphibians: A subclass of amphibians that includes all the living amphibians in the order Anura, Urodela and Apoda.

Metamorphosis: The process of changing from one form to another during development. In amphibians it is usually associated with a switch from an aquatic larval stage to a terrestrial adult phase.

Metapodials: Any one of the bones of a limb lying between the mesopodials and phalanges; the long bones making up the proximal part of a digit, lying in the fleshy part of the foot. There are two types: metacarpals and metatarsals (Peters, 1964).

Metatarsal: Any one of the metapodial bones in the hind foot.

Metacarpal: The rod-shaped bones of the forefoot of tetrapods, articulating with the carpal bones proximally and with the phalanges distally.

Neotropical: Including, belonging to, or characteristic of, tropical South America as a zoogeographical region. Means "new" tropics, referring to American continents as the "new world."

Ossified: Made or converted into bone.

Papilla: A small, nipple-like or pimple-like skin projection; usually fleshy and pliable.

Paratype: Specimen other than the holotype that the author uses when describing the species.

Periosteum: The connective tissue covering a bone.

Pollywogs: Referring to a particular type of tadpole: one that has a narrow fin restricted to the tail or extending only a slight distance onto the posterior part of the body.

Parotid Glands: Poison glands that are used for defense mechanism. They are usually located on the dorsal surface of the body behind the head.

Sexual Dimorphism: Referring to the differences in males and females in addition to sex organs, such as different size or color in males and females. Read more

Snout-vent length (or SVL): The body length measured as the distance between the tip of the snout and the end of the anus (vent).

Spermatophores: A clump or packet of sperm encapsulated in mucoid material. In amphibains, only salamanders produce spermatophoes, and then only by some salamanders (all the ones with internal fertilization, i.e., in all but Hynobiidae, Cryptobranchidae and Sirenidae).

Sternum: The bone that is present on the mid-ventral surface of the chest.

Subgular: Below the throat.

Synanthropization: Living jointly with humans, also human commensal

Tarsus: Posterior part of the foot. This term is used to describe the bones that make up the posterior part of the foot.

Terra typica: The native habitat for a species, or the typical habitat where the species can be found.

Trogloxene: Any organism that spends some of its time in dark caves.

Tibia: The bone on the medial side of the lower leg, in line with the first digit.

Tubercle: A small, rounded projection or protuberance on the surface of the body.

Tympanum: The membrane covering the external opening of the middle ear chamber or vestibule.

Vocal Cords: These are pair of elastic fibers stretched across the larynx in amphibians, reptiles and birds. The cords produce sounds as air is expelled.

Vomerine teeth: These teeth are borne on the vomer and are used for holding food. Vomer refers to the bone in the front part of the mouth.

Urostyle: Spike-like caudal part of the frog's vertebral column. It consists of two fused caudal vertebrae and serves as the attachment point for muscles used in jumping.

Zygote: Cell that is formed by the fusion of the sperm and the egg: fertilized egg cell.


Holmes, Sandra. 1988. Henderson's Dictionary of Biological Terms. Longman Group Limited.

Peters, J. 1964. Dictionary of Herpetology. Hafner Publishing Company, New York & London.