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Mimic poison dart frog
Tarapoto dart
Physical description
Binomial nameRanitomeya imitator
HabitatTropical rainforest
Lifespan8-12 years
Average Size1.3 cm (0.5 in)
Average weight1.25 grams
DietInsectivorous
Conservational Status
StatusLeast concern
IUCN status3.1
Scientific classification
PhylumChordata
ClassAmphibia
OrderAnura
FamilyDendrobatidae
GenusRanitomeya
SpeciesR. imitator
Distribution
Distribution of speciesEastern Peru, possibly Brazil

The mimic poison dart frog, Ranitomeya imitator, is a species of poison dart frog native to the tropical rainforests of eastern Peru and possibly western Brazil as well. As both its common and scientific names indicate, it bears a close resemblance to Ranitomeya ventrimaculata and Ranitomeya variabilis. It is threatened by habitat loss.

Poison

Like many Ranitomeya species, the mimic poison dart frog's toxins are relatively weak. Its skin secretes pumiliotoxin C, a less-potent version of the pumiliotoxins secreted by the Dendrobates and Oophaga species. Pumiliotoxin C, like other pumiliotoxins, interferes with muscle contraction in the heart and skeletal muscle. The very small amount of poison that the mimic poison dart frog carries is nonetheless enough to cause illness in humans.

Pumiliotoxin is deadly in high concentrations. Pumiliotoxin is weaker than allopumiliotoxin and especially batrachotoxin, with a lethal dose of 2 mg (R. imitator carries about a quarter milligram). There are three different types of this toxin A, B and C. The toxin works by affecting the calcium channels. Some of the symptoms of pumiliotoxins are partial paralysis, having difficulty moving, being hyperactive and in some cases it can result in death.

Description

The mimic poison dart frog is very similar to Zimmermann's poison dart frog, but slightly smaller, at around 1.3 cm in length. It is also bulkier, having a somewhat pudgy appearence. It possesses toe discs, a feature not seen in R. variabilis.

Climbimi

Female specimen demonstrating this species' highly arboreal tendencies.

It is difficult to decide whether R. imitator should be referred to as primarily black or primarily green or orange. The black areas are usially prominent, rounded, and widely separated by a reticulum of the conteasting color. The secondary colour is often yellowish-green, but may also be lime green, pale green, yellow, orange, or even copper-coloured. The limbs bear tiny, fragmented spots of black separated by a reticulum of blue or green.

As it is somewhat variable, R. imitator can be extremely difficult to differentiate from R. variabilis. The former is generally smaller than the latter, but there is some overlap in size. A more consistent means of differentiation is the number of spots on the nose (Ranitomeya imitator has two while R. variabilis only has one).

Reproduction

thumb|300px|left|Male calling from a bromeliad. As with most dendrobatine poison dart frogs, groups of mimic poison frogs gather in large, relatively dense breeding groups. Like most Ranitomeya species, they are highly arboreal and so the breeding territories are usually three-dimensional. Each male will clear a territory of one or two cubic metres, attacking any intruders, and calling to females with a pleasing trill.

Once a male has caught the attention of a female, they court in the same fashion as R. reticulata. Eventually, she will lay a clutch of five to seven eggs, which are then fertilized by the male. Amplexus is absent in the mimic poison dart frog, which is another difference between it and Zimmermann's poison dart frog.

Ranitomeya imitator and related frogs exhibit a degree of parental care, with the female laying feeder eggs for the tadpoles to eat. However, unlike the strawberry poison dart frog and related species, this behavior is not required and tadpoles can survive on invertebrates, algae, and detritus.

In captivity

The mimic poison dart frog thrives in captivity in small colonies and breeding is easily achieved once animals reach sexual maturity, usually in less than six months. Though they are small frogs, they will make use of all the vivarium space provided them.

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