Eleutherodactylus thorectes

Geographic Range

Macaya breast-spot frogs (Eleutherodactylus thorectes) live in the Neotropics. They live in a very restricted area of Haiti. They are endemic to the Massif de la Hotte mountain range, on the peaks of Forman and Macaya. This habitat is critical to their survival because of their incredibly small size and critically endangered population. (Hedges, et al., 2010)

Habitat

Macaya breast-spot frogs inhabit the subtropical climate of the Massif de la Hotte mountain range. This habitat is referred to as a cloud forest, at an elevation of 1,700 to 2,340 m above sea level. This landscape consists of pines, ferns, shrubs, and bamboo. They are primarily terrestrial and do not need large bodies of water in which to lay their eggs. Macaya breast-spot frogs have such a specific habitat because their survival depends on such specific conditions. (Hedges, et al., 2010)

  • Range elevation
    1,700 to 2,340 m
    to ft
  • Average elevation
    2,020 m
    ft

Physical Description

Macaya breast-spot frogs are some of the smallest amphibians in the world, with an average snout-vent length (SVL) of 12 to 15 mm. Their bodies are slimmer than their heads, and they are longer in length than they are in width. Macaya breast-spot frogs have brown and orange coloring to blend into their terrestrial surroundings. Since they are critically endangered, there is not much information on their appearance in the wild, but female and males seem to share most of the same characteristics. Macaya breast-spot frogs have dark, spotted patterns on their heads, backs, and even their breasts, which is where they get their nickname. (Sartore, 2020; "Taxonomy browser (Eleutherodactylus thorectes)", 2010)

  • Sexual Dimorphism
  • sexes alike
  • Range length
    12 to 15 mm
    0.47 to 0.59 in

Development

Macaya breast-spot frogs go through direct development. They hatch from eggs looking like a smaller version of adults and grow until they reach their mature size of about 12 to 15 mm. Sex is determined in a homomorphic process, which means that sex is determined in the early stages of development.

Most amphibians, including Macaya breast-spot frogs, can switch from one sex to another by stimulation with sex steroids. The gender of these frogs can be changed in a relatively short amount of time if environmental pressures call for either more females or males to balance a population. ("Taxonomy browser (Eleutherodactylus thorectes)", 2010)

Reproduction

Macaya breast-spot frogs are polygynandrous, meaning both males and females have multiple different mates within one lifetime. Females lay their eggs on the damp forest floor. Researchers have discovered that Macaya breast-spot frogs are the smallest of all oviparous (egg-laying) amphibians. (Green and Sessions, 1991; Hedges, 1988)

There is barely any information on the mating habits of Macaya breast-spot frogs. It is extremely hard to observe them in the wild because of their critically endangered status and their very small size. Upon birth, young are immediately independent. ("Taxonomy browser (Eleutherodactylus thorectes)", 2010)

  • Breeding interval
    Thought to be multiple times a year during warmer seasons.
  • Breeding season
    Specifics are unknown.
  • Range number of offspring
    1 to 3

Macaya breast-spot frogs do not exhibit any parental investment. After she lays her eggs, mothers will leave and not return. Once eggs hatch, offspring separate from their siblings and go off to develop into adults and mate on their own. ("Eleutherodactylus thorectes Hedges, 1988", 2020; Hedges, et al., 2010)

  • Parental Investment
  • no parental involvement
  • pre-hatching/birth

Lifespan/Longevity

Not much is known about the lifespan of Macaya breast-spot frogs, since they are very hard to track and observe over long periods of time. Macaya breast-spot frogs are critically endangered, primarily from habitat loss. This habitat loss is due to the pressure on Haiti to produce charcoal, lumber, and agricultural land. Statistical data from 2016 stated that there would be an 80% decline in the Macaya breast-spot frog population in the next 10 years. (Hedges, 1988; Hedges, et al., 2010)

  • Range lifespan
    Status: captivity
    1 to 5 years
  • Average lifespan
    Status: captivity
    2.5 years
  • Typical lifespan
    Status: wild
    5 to 10 years
  • Typical lifespan
    Status: captivity
    2 to 5 years

Behavior

Macaya breast-spot frogs are a solitary species. They have long, muscular legs, which help them move through their environment. Macaya breast-spot frogs can jump almost 20 times their own body length. At night they forage, move to safer grounds, or lay eggs. ("Eleutherodactylus thorectes Hedges, 1988", 2020; Smith and Sutherland, 2014; "Taxonomy browser (Eleutherodactylus thorectes)", 2010)

Home Range

Macaya breast-spot frogs live in the Massif de la Hotte mountain range in Haiti. Since they are so small, they do not cover a large amount of land in their lifetimes. From what researchers say, Macaya breast-spot frogs are able to live in a range with other frogs of the same species. (Hedges and Powell, 1998; Moore, 2008; Rittmeyer, et al., 2012)

Communication and Perception

Macaya breast-spot frogs primarily use acoustic communication, but this is mostly restricted to mating calls. These mating calls can only be produced by males, and resemble a soft clucking produced at a fast frequency. (Moore, 2008)

  • Other Communication Modes
  • duets

Food Habits

The diet of Macaya breast-spot frogs mainly consists of small insects that also reside in the Massif de la Hotte region of Haiti. They forage nocturnally and do not need very feed often.

  • Animal Foods
  • insects

Predation

The extremely small size of Macaya breast-spot frogs is their biggest anti-predator adaptation. They are able to blend into surrounding terrain and not be seen by predators. During the day, Macaya breast-spot frogs use their surroundings to hide on land and rest while diurnal predators. (Hedges and Powell, 1998; Rittmeyer, et al., 2012)

  • Anti-predator Adaptations
  • cryptic
  • Known Predators
    • Specific predators are unknown.

Ecosystem Roles

The effect that Macaya breast-spot frogs play on their environment is hard to measure. Since The Massif de la Hotte region in Haiti is threatened by coal mining and slash and burn agriculture, their habitat is already under stress and change. Without a stable environment, differences in the ecosystem made by one small species cannot be determined, due to the larger scale changes occurring simultaneously.

Commensal/Parasitic Species
  • possibly parasitic nematodes

Economic Importance for Humans: Positive

Macaya breast-spot frogs play a small role in the immense diversity of the Massif de la Hotte mountain range. They bring in eco-tourists from all over the world looking for an experience in the natural habitat. Now that this habitat is being destroyed, tourism is declining and creating an economic disparity for the companies and businesses that rely on revenue obtained from eco-tourists. ("Taxonomy browser (Eleutherodactylus thorectes)", 2010)

Economic Importance for Humans: Negative

There are no known negative economic effects of Macaya breast-spot frogs.

Conservation Status

Macaya breast-spot frogs are a critically endangered species according to the IUCN Red List. Their population has not been counted since some time between 1980 and 1990. However, there have been predictions of massive decline in the remaining amphibian populations in the Massif de la Hotte mountain region. Scientists think that more than 80% of the Macaya breast-spot frog has become extinct since 1990.

Other Comments

There is not much information on Macaya breast-spot frogs because they are extremely hard to observe in the wild. Most of the information known about them is from capture, observation, and research in lab conditions.

Contributors

Anna Waddell (author), Colorado State University, Brooke Berger (editor), Colorado State University, Galen Burrell (editor).

Glossary

Neotropical

living in the southern part of the New World. In other words, Central and South America.

World Map

acoustic

uses sound to communicate

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carnivore

an animal that mainly eats meat

cryptic

having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.

duets

to jointly display, usually with sounds in a highly coordinated fashion, at the same time as one other individual of the same species, often a mate

ecotourism

humans benefit economically by promoting tourism that focuses on the appreciation of natural areas or animals. Ecotourism implies that there are existing programs that profit from the appreciation of natural areas or animals.

ectothermic

animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

indeterminate growth

Animals with indeterminate growth continue to grow throughout their lives.

insectivore

An animal that eats mainly insects or spiders.

island endemic

animals that live only on an island or set of islands.

metamorphosis

A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

nocturnal

active during the night

polygynandrous

the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.

saltatorial

specialized for leaping or bounding locomotion; jumps or hops.

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

solitary

lives alone

terrestrial

Living on the ground.

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

visual

uses sight to communicate

References

Darrel Frost and The American Museum of Natural History. 2020. "Eleutherodactylus thorectes Hedges, 1988" (On-line). American Museum of Natural History. Accessed February 09, 2020 at http://research.amnh.org/vz/herpetology/amphibia/Amphibia/Anura/Brachycephaloidea/Eleutherodactylidae/Eleutherodactylinae/Eleutherodactylus/Eleutherodactylus-thorectes.

2010. "Taxonomy browser (Eleutherodactylus thorectes)" (On-line). NCBI. Accessed February 09, 2020 at https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=448498.

Green, D., S. Sessions. 1991. The influence of life history on karyotypic evolution in frogs. San Diego, California: Academic Press INC.. Accessed February 09, 2020 at https://books.google.com/books?The+influence+of+life+history+on+karyotypic+evolution+in+frogs.

Hedges, S. 1988. A new diminutive frog from Hispaniola (Leptodactylidae: Eleutherodactylus). Copeia, Issue 3: 636-641. Accessed March 01, 2020 at http://search.proquest.com/docview/15580697/.

Hedges, S., R. Powell. 1998. Eleutherodactylus thorectes. Catalogue of American Amphibians and Reptiles (CAAR), 677: 1-2.

Hedges, S., R. Thomas, R. Powell. 2010. "Eleutherodactylus thorectes" (On-line). Red List. Accessed February 09, 2020 at https://www.iucnredlist.org/species/57004/11563733.

Moore, R. 2008. "Eleutherodactylus thorectes" (On-line). Accessed February 09, 2020 at https://www.iucnredlist.org/species/57004/11563733.

Rittmeyer, E., A. Allison, M. Gr√ľndler, D. Thompson, C. Austin, W. Etges. 2012. Ecological Guild Evolution and the Discovery of the World's Smallest Vertebrate. PLoS ONE, Volume 7(1): all. Accessed March 01, 2020 at https://doi.org/10.1371/journal.pone.0029797.

Sartore, J. 2020. "Photo: Macaya breast-spot frog (Eleutherodactylus thorectes) at the Philadelphia Zoo. This species is found in Haiti and is critically endangered. ANI101-00268" (On-line). Joel Sartore. Accessed February 09, 2020 at https://www.joelsartore.com/ani101-00268/.

Smith, R., W. Sutherland. 2014. Amphibian Conservation: Global evidence for the effects of interventions. University of Cambridge: Pelagic Publishing. Accessed February 09, 2020 at https://books.google.com/books?id=4Ep_BAAAQBAJ&printsec=frontcover&dq=Amphibian+Conservation:+Global+evidence+for+the+effects+of+interventions.