The yellow-throated frog, Trinidadian stream frog, or Trinidad poison frog (''Mannophryne trinitatis)'' is a diurnal species of

frog A frog is any member of a diverse and largely semiaquatic group of short-bodied, tailless amphibian vertebrates composing the order (biology), order Anura (coming from the Ancient Greek , literally 'without tail'). Frog species with rough ski ...

in the family Aromobatidae that is endemic to the island of

Trinidad Trinidad is the larger, more populous island of the Republic of Trinidad and Tobago, the country. The island lies off the northeastern coast of Venezuela and sits on the continental shelf of South America. It is the southernmost island in ...

in the

Republic of Trinidad and Tobago Trinidad and Tobago, officially the Republic of Trinidad and Tobago, is the southernmost island country in the Caribbean, comprising the main islands of Trinidad and Tobago, along with several List of islands of Trinidad and Tobago, smaller i ...

. Trinidad poison frogs can be found in rocky streams in moist

montane Montane ecosystems are found on the slopes of mountains. The alpine climate in these regions strongly affects the ecosystem because temperatures lapse rate, fall as elevation increases, causing the ecosystem to stratify. This stratification is ...

forests. The species has cryptic coloration and is sexually dimorphic. ''Mannophryne venezuelensis'' from the

Paria Peninsula The Paria Peninsula () is a large peninsula on the Caribbean Sea, in the state of Sucre in northern Venezuela. Geography Separating the Caribbean Sea from the Gulf of Paria, the peninsula is part of the mountain range, in the Venezuelan Coa ...

Venezuela Venezuela, officially the Bolivarian Republic of Venezuela, is a country on the northern coast of South America, consisting of a continental landmass and many Federal Dependencies of Venezuela, islands and islets in the Caribbean Sea. It com ...

were also formerly included in this species. Currently this species is listed as of "Least Concern" on IUCN, but there is a general lack of understanding of its distribution. The frog experiences habitat loss. Both sexes are territorial and provide parental care together.

Description

Adult Trinidad poison frogs are a relatively small and diurnal species. Their dorsal surface is brown and dark and their flanks are mottled. The Trinidad poison frog is sexually dimorphic. Adult males have grey throats and average 25 mm in snout-vent length. Females have bright yellow throats and average 28 mm. Adult males can also change their skin color from pale brown to jet black when they engage in mate-calling to attract females.Downie, J. R., & Cormack, S. R. L. A. J. R. (2001). Selection of tadpole deposition sites by male Trinidadian stream frogs, Mannophryne trinitatis (Dendrobatidae) an example of antipredator behaviour. Herpetological Journal, 11(3), 91–100.

Tadpole A tadpole or polliwog (also spelled pollywog) is the Larva, larval stage in the biological life cycle of an amphibian. Most tadpoles are fully Aquatic animal, aquatic, though some species of amphibians have tadpoles that are terrestrial animal, ...

s, in contrast, start around 14 mm to 16 mm in length and later grow to around 37 mm after metamorphosing. The Trinidad poison frog has a well-defined and solid pigmented collar and a solid brown dorsum. It has well defined pale dorsolateral stripes and dark pigmentation around the external margin of its soles and palms. It also has a well-defined pale inguinal stripe, bandlike concentrations of melanophores along the anterior arms, and dark pigmentation on the metatarsal and subarticular tubercles of its toes.

Habitat and distribution

The Trinidad poison frog is only found in the

of Northern

and the Northern and Central Ranges of

, West Indies.Jowers, M., & Downie, J. (2004). Distribution of the frog Mannophryne trinitatis (Anura: Dendrobatidae) in Trinidad, West Indies. Living World, 2004. The frog can live anywhere ranging from sea level to extremely high elevations and prefers to reside around rocky streams in valleys, mountain slopes, or undisturbed moist montane forests. The streams are typically narrow and shallow with slow, clear running waters and contain deeper pools where frogs can deposit and develop their

tadpole A tadpole or polliwog (also spelled pollywog) is the Larva, larval stage in the biological life cycle of an amphibian. Most tadpoles are fully Aquatic animal, aquatic, though some species of amphibians have tadpoles that are terrestrial animal, ...

s. Frogs will sometimes transport their tadpoles from these streams to live in other pools such as phytotelmata if a large number of predators exist nearby.

Conservation

The Trinidad poison frog is currently listed on the

IUCN Red List The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is an inventory of the global conservation status and extinction risk of biological ...

as “least concern”, and is not present on the CITES Endangered Species List. However, a significant number of frogs have suffered regional

habitat loss Habitat destruction (also termed habitat loss or habitat reduction) occurs when a natural habitat is no longer able to support its native species. The organisms once living there have either moved elsewhere, or are dead, leading to a decrease ...

and degradation through pollution, deforestation, and

shifting cultivation Shifting cultivation is an agricultural system in which plots of land are cultivated temporarily, then abandoned while post-disturbance fallow vegetation is allowed to freely grow while the cultivator moves on to another plot. The period of cul ...

. Additionally, populations of the frog may be disappearing before they can be recorded due to a lack of population genetics analyses. One study from

, proposed direct conservation measures include forest preservation and strict regulations on agrochemical products used on coffee and cocoa plantations near streams.Manzanilla, J., Jowers, M., Marca, E., & García-París, M. (2007). Taxonomic reassessment of Mannophryne trinitatis (Anura: Dendrobatidae) with a description of a new species from Venezuela. The Herpetological Journal, 17, 31–42.

Home range and territoriality

Trinidad poison frogs engage in two types of territorial defense. The first involves nonreproductive regions where frogs will defend resource access to food, water, and shelter. The second involves large reproductive regions where frogs will defend against conspecific calling rivals during the breeding season.Pröhl, H. (2005). Territorial Behavior in Dendrobatid Frogs. Journal of Herpetology, 39(3), 354–365. Adult females engage in territorial defense more often than males.Cummins, C. P., & Swan, M. J. S. (1995). Variation in Reproductive Characteristics of the Stream Frog Colostethus trinitatis on the Island of Trinidad. Journal of Tropical Ecology, 11(4), 603–618. Adult female Trinidad poison frogs display territorial defense against other frogs through aggressive behaviors such as visual threat displays, wrestling, and chasing. During threat displays, females will reveal their bright yellow throats against intruders.Greener, M. S., Hutton, E., Pollock, C. J., Wilson, A., Lam, C. Y., Nokhbatolfoghahai, M., Jowers, M. J., & Downie, J. R. (2020). Sexual dichromatism in the neotropical genus Mannophryne (Anura: Aromobatidae). PLOS ONE, 15(7), e0223080. Adult males, in contrast, defend their territories against both predators and other male intruders by producing advertisement calls at their calling sites. Such defense is intended to deter competitors and attract females as potential mates.

Diet

Adult Trinidad poison frogs often feed on

arthropod Arthropods ( ) are invertebrates in the phylum Arthropoda. They possess an arthropod exoskeleton, exoskeleton with a cuticle made of chitin, often Mineralization (biology), mineralised with calcium carbonate, a body with differentiated (Metam ...

s and small insects such as ''

Drosophila ''Drosophila'' (), from Ancient Greek δρόσος (''drósos''), meaning "dew", and φίλος (''phílos''), meaning "loving", is a genus of fly, belonging to the family Drosophilidae, whose members are often called "small fruit flies" or p ...

'' ('' D. hydei'' and '' D. melanogaster'') and ''

Callosobruchus chinensis ''Callosobruchus chinensis'', also known as the adzuki bean weevil, pulse beetle, Chinese bruchid or cowpea bruchid, is a common species of beetle found in the bean weevil subfamily. Although it is commonly known as the "adzuki bean weevil" it i ...

''. In contrast, tadpoles are usually

herbivorous A herbivore is an animal anatomically and physiologically evolved to feed on plants, especially upon vascular tissues such as foliage, fruits or seeds, as the main component of its diet. These more broadly also encompass animals that eat n ...

and feed on algae and leaf litter. Frogs and tadpoles also consume bat

guano Guano (Spanish from ) is the accumulated excrement of seabirds or bats. Guano is a highly effective fertiliser due to the high content of nitrogen, phosphate, and potassium, all key nutrients essential for plant growth. Guano was also, to a le ...

and invertebrate infauna as food.

Reproduction and mating

Reproductive characteristics such as intraovarian clutch size and tadpole size for Trinidad poison frogs differ according to the frog's biogeography. In

, clutch size ranged from 6 in to 13 in from the

Northern Range The Northern Range is the range of tall hills across north Trinidad, the major island in the Republic of Trinidad and Tobago. The hills range from the Chaguaramas peninsula on the west coast to Toco in the east. The Northern Range covers appro ...

and 12 in to 26 in from the Tamana cave of the Central Range hills. Adult males court females from a distance by producing advertisement calls. Additionally, they engage in throat display and toe tip jumping. As they vocalize, their skin color changes from pale brown to jet black. When a nearby female receives a male's call signal or notices its skin coloration, the female will leave its territory and approach the calling male to engage in

amplexus Amplexus (Latin "embrace") is a type of Mating, mating behavior exhibited by some External fertilization, externally fertilizing species (chiefly amphibians, Amphipoda, amphipods, and horseshoe crabs) in which a male grasps a female with his fro ...

. The pair then moves to oviposition sites such as rock crevices or wet leaves near streams.

Parental care

Adult female Trinidad poison frogs lay their eggs near streams following increased humidity from rainfall.Praderio, M. J., & Robinson, M. D. (1990). Reproduction in the Toad Colostethus trinitatus (Anura: Dendrobatidae) in a Northern Venezuela Seasonal Environment. Journal of Tropical Ecology, 6(3), 333–341. Adult males then guard and tend to the eggs until they hatch after about 21 days. When predation risk is high, males will transport their tadpoles on their backs for long distances between 3 and 4 days and selectively deposit them into predator free pools. Such tadpole transportation does not incur significant costs on adult males in terms of reduced feeding. Males are unable to breed with females while transporting tadpoles.

Enemies

The Trinidad poison frog and its tadpoles are commonly preyed on by a killifish species ('' Anablepsoides hartii)'' and shrimp of the genus '' Macrobrachium''. The frog species also suffers from various intestinal parasites, or helminths, such as

cestodes Cestoda is a class of parasitic worms in the flatworm phylum (Platyhelminthes). Most of the species—and the best-known—are those in the subclass Eucestoda; they are ribbon-like worms as adults, commonly known as tapeworms. Their bodies con ...

nematode The nematodes ( or ; ; ), roundworms or eelworms constitute the phylum Nematoda. Species in the phylum inhabit a broad range of environments. Most species are free-living, feeding on microorganisms, but many are parasitic. Parasitic worms (h ...

s, and

acanthocephala Acanthocephala ( Greek , ' 'thorn' + , ' 'head') is a group of parasitic worms known as acanthocephalans, thorny-headed worms, or spiny-headed worms, characterized by the presence of an eversible proboscis, armed with spines, which it uses t ...

ns.Kaiser, H. (2002). Intestinal helminths of seven frog species from Trinidad and Tobago. Caribbean Journal of Science, 38(1-2), 147-150.

References

{{Taxonbar, from=Q1936453 trinitatis Amphibians of Trinidad and Tobago Endemic fauna of Trinidad and Tobago Taxa named by Samuel Garman Amphibians described in 1888 Taxonomy articles created by Polbot