Mannophryne trinitatis (Garman, 1888)

Common Name and Adult Activity

Adult Mannophryne trinitatis, commonly called the Trinidad poison frog, are a relatively small, diurnal species.

Dorsal and Flank Coloration

Their dorsal surface is dark brown, and their flanks are mottled.

Sexual Dimorphism

This species is sexually dimorphic: adult males have grey throats, with an average snout-vent length of 25 mm, while females have bright yellow throats, with an average snout-vent length of 28 mm.

Male Color Change During Calling

When adult males perform mate-calling to attract females, they can change their skin color from pale brown to jet black.

Life Stage Lengths

Newly metamorphosed individuals reach around 37 mm in length, while tadpoles measure between 14 mm and 16 mm at hatching.

Pigmented Collar and Dorsum

This species has a well-defined, solidly pigmented collar and a solid brown dorsum.

Markings and Pigmentation Patterns

It also has well-defined pale dorsolateral stripes, dark pigmentation around the outer edge of its soles and palms, a well-defined pale inguinal stripe, band-like clusters of melanophores along the front of the arms, and dark pigmentation on the metatarsal and subarticular tubercles of the toes.

Species Distribution

The Trinidad poison frog is found only on the Paria Peninsula of northern Venezuela, and in the Northern and Central Ranges of Trinidad, West Indies.

Elevation and Habitat Preferences

It inhabits areas from sea level up to very high elevations, and prefers habitats around rocky streams in valleys, mountain slopes, or undisturbed moist montane forests.

Breeding Stream Characteristics

These streams are typically narrow, shallow, with slow-moving clear water, and contain deeper pools where frogs deposit and raise their tadpoles.

Tadpole Transport Behavior

If there are many predators in the original stream, adults will sometimes transport their tadpoles to other pools, such as phytotelmata.

Territorial Defense Forms

Trinidad poison frogs use two forms of territorial defense.

Nonreproductive Territory Purpose

The first occurs in nonreproductive areas, where frogs defend access to resources including food, water, and shelter.

Reproductive Territory Purpose

The second occurs in large reproductive areas, where frogs defend their space against calling conspecific rivals during the breeding season.

Territorial Defense Frequency by Sex

Adult females engage in territorial defense more frequently than males.

Female Aggressive Defense Behaviors

Adult females use aggressive behaviors including visual threat displays, wrestling, and chasing to defend territories against other frogs.

Female Threat Display Trait

During threat displays, females display their bright yellow throats to intruders.

Male Territory Defense Method

In contrast, adult males defend their territories against both predators and other male intruders by producing advertisement calls from their calling sites.

Male Call Functions

This defense both deters competitors and attracts females as potential mates.

Biogeographic Variation in Reproductive Traits

Reproductive traits of the Trinidad poison frog, including intraovarian clutch size and tadpole size, vary based on the population's biogeography.

Clutch Size by Population

In Trinidad, clutch sizes range from 6 to 13 eggs for populations in the Northern Range, and from 12 to 26 eggs for populations in Tamana Cave in the Central Range hills.

Male Courtship Behaviors

Adult males court females from a distance by producing advertisement calls.

Additional Male Courtship Displays

They also perform throat displays and toe-tip jumping.

Male Color Change During Courtship

As they vocalize, their skin changes color from pale brown to jet black.

Female Response to Courtship

When a nearby female detects a male's call or notices his skin color change, she leaves her own territory, approaches the calling male, and engages in amplexus.

Oviposition Site Movement

The pair then moves to an oviposition site such as a rock crevice or wet leaf near a stream.