Frog   Glossary   T

Taxonomy: The science of classification of plants and animals.
Terrestrial: Land-dwelling. Toads are an example of an amphibian that prefers land, and could be lightly referred to as a more terrestrial amphibian than a frog; although the toad must still have a nearby source of water and a chance to keep his skin moist.
Thermoregulate: To regulate (body) temperature by choosing a warmer or cooler climate or environment.
Thigmothermic: Pertaining to a species (often nocturnal) that thermoregulates by being in contact with a warm surface such as a boulder or tarred road surface. (We often see turtles "sunning themselves" by climbing from a cool deep lake onto a large stone on the banks.)
Topical: Referring to the surface part of the body, as in "skin". Can also be referring to a treatment or drug applied to the skin surface.
Trematodes: trematodes are parasitic flatworms that involve two or more hosts. Species in the genus Ribeiroia use three hosts: snails, larval amphibians or fish, and birds or mammals. Snails function as the first hosts, in which the parasite undergoes asexual reproduction (i.e. does not need another worm to mate) to produce free-swimming cercariae. Cercariae then infest themselves within the developing limbs of larval amphibians. Here they rest and begin to interfere with the amphibians' limb development. This will take them to the next stage in this parasitic soup.

For the parasite to complete its life cycle, the infected amphibian must be full of the parasites. Some of them such as the Ribeiroia will now leave the frog and seek out birds such as herons, raptors, or waterfowl within which the adult parasite now reproduces sexually and releases eggs in the host feces. Eggs hatch in water, releasing free-swimming miracidia that infect planorbid snails, continuing the cycle.

Malformations, which are suspected to increase the susceptibility of infected frogs to predation, may actually enhance transmission of Ribeiroia between its second intermediate (amphibians) and definitive hosts (birds). A variety of other parasites with complex life cycles are known to alter either the appearance or behavior of their second intermediate hosts, effectively rendering them more vulnerable to predatory definitive hosts. See also: Cercariae, monogenea(Fish and amphibians as hosts) and Planorbid  (snail) and Trypanosomatidae right below this term.

Trypanosomatidae: A family of protozoa containing flagellated parasites which have the ability to change their morphology. Their hosting stages can include one or all three hosts including plant, invetebrate and veterbrate. The genus most infecting amphibians is found in Africa.

For more information and the source of the above information, please see Trematode Parasite infestation








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