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Edalorhina perezi

By Kelsey Bowe

Geographic Range

Perez's snouted frogs are found east of the Andes mountains in western Amazonia throughout Peru, Ecuador, southern Columbia, and western Brazil. (Bartlett and Bartlett, 2003; Duellman and Morales, 1990)

Habitat

Edalorhina perezi, commonly called Perez's snouted frogs or eyelashed forest frogs, lives in leaf litter in lowland tropical rain forests, premontane forests, and floodplain forests of the Amazon region. These are diurnal frogs that remain on the forest floor and are most active after rainfall. They are found from 200 to 1100 meters above sea level. Tadpoles develop in temporary pools of water on the forest floor. They are most often found in pools near tree falls, as the uprooted trees leave many holes for rainfall to collect. (Angulo, et al., 2004; Bartlett and Bartlett, 2003; Duellman and Morales, 1990; Murphy, 1999)

  • Aquatic Biomes
  • temporary pools
  • Range elevation
    200 to 1100 m
    656.17 to 3608.92 ft

Physical Description

Perez's snouted frogs are cryptic in their habitats and resemble a dead leaf when observed from above. These frogs have dorsolateral folds running from behind each eye to the hind leg insertions, making them appear flat from above. Dorsal color varies and is typically a mottling of gray with light and dark brown. Five to seven stripes may also be present on the dorsum. Dorsal skin texture can be smooth or contain anywhere from a few to many tubercles. Different populations exhibit particular patterns of color and texture, although overlapping body types within an area can occur. Sides of the body are black. The underside of the body and limbs is white with black blotches and can also contain bright yellow blotches. These patterns vary by individual and region and may be mostly white to completely black with only a white throat. Yellow coloring may be absent or abundant. Most individuals have a rounded orange area with a black spot in the groin. Perez's snouted frogs have a rounded snout and usually a cone shaped tubercle protrudes from the tip. This tubercle is prominent in some specimens from Ecuador, absent from some in Peru, while most individuals have an intermediate form of this structure. Members of this species also have three or more noticeable tubercles on the edge of their upper eyelids, looking like small horns or eyelashes. An oval shaped tympanum is visible behind the eye. The hind feet are slightly webbed. Jaws contain poorly developed vomerine teeth, where often they are only present on one of the two paired bones. A very small percent of individuals lack vomerine teeth altogether. Maxillary teeth are present in the jaw. (Bartlett and Bartlett, 2003; Cope, 1874; Duellman and Morales, 1990; Dunn, 1949)

  • Sexual Dimorphism
  • female larger
  • Range length
    24 to 37 mm
    0.94 to 1.46 in

Development

Perez's snouted frogs undergo complete metamorphosis. Tadpoles are initially white, but eventually become brown. On the first day after hatching they remain motionless in the water. Hatchlings still have their yolk sacs attached to them and have mouthparts with two rows of upper and lower denticles. Tadpoles have an average total length of 10.5 mm and an average body length of 4.1 mm. Tadpoles do not have external gills. Tadpoles begin feeding on their second day post-hatching. (Bartlett and Bartlett, 2003; Duellman and Morales, 1990; Schlüter, 1990)

Reproduction

Perez's snouted frogs are unique anurans in that they do not lay their eggs directly in water; instead they are laid in a foam nest constructed of secretions from the female. Males vocalize with advertisement calls, sounding like four or five short, whistle-like notes, to attract a female. Once a female chooses a mate, the pair begins axillary amplexus which can last for up to six days. When the female is ready to lay her eggs, she will move closer to the pool or water-filled log cavity where the eggs will be laid. The female initiates nest building during amplexus by arching her back, the male will then place his feet directly behind her cloaca and beat the secretions of the female into a foam; included in the secretions are the eggs which are fertilized as they are expelled from the cloaca. The male will beat the secretions for 10 to 12 seconds and then spread the surface of the foam by stretching his legs. Beating will resume when the female signals the male by arching her back again; this process continues until the nest is completed, which can take 30 minutes to 2 hours. Nests have been found between 60 and 70 mm in diameter and are hemispherical in shape. Average nests contain 30 to 40 eggs, but some have been found with as few as 12 and as many as 100. (Bartlett and Bartlett, 2003; Duellman and Morales, 1990; Schlüter, 1990)

Tadpoles hatch and emerge from their foam nests after three to five days, then drop into the pools of water under the nest. Time from hatching to complete metamorphosis is dependent on multiple factors. The depth, temperature, and drying rate of pools will affect tadpole development, as well as the amount of food sources in the pool. Density of predators and competing tadpoles may also play a role. It is difficult to measure the length of time for a tadpole to develop because many nests may surround a single pool and tadpoles will hatch at different times. Once many tadpoles are in a pool, individuals from certain nests cannot be distinguished. The estimated length of time for metamorphosis is 21 to 28 days based on lab observations. (Duellman and Morales, 1990; Murphy, 1999; Schlüter, 1990)

  • Breeding interval
    Usually a mating pair produces a single nest in a night, but can build as many as three in a single mating event (Schlüter, 1990).
  • Breeding season
    Breeding occurs during the daytime, throughout the rainy season in the species’ range (Schlüter, 1990). The rainy season occurs from late October to early April (Murphy, 2003). Females in a lab setting were able to lay clutches of eggs every four weeks, although this may vary in wild populations (Murphy, 1999).
  • Range number of offspring
    12 to 100
  • Average number of offspring
    30-40
  • Range time to hatching
    3 to 5 days
  • Range time to independence
    21 to 28 days

No records of post-nesting parental care have been documented. It is assumed that, after the nest has been created, neither the male nor the female guards it. Tadpoles hatch and develop in their aquatic habitat on their own. (Schlüter, 1990)

  • Parental Investment
  • pre-fertilization
    • provisioning
    • protecting
      • female

Lifespan/Longevity

No information was found on lifespan in this species.

Behavior

Non-breeding behavior has apparently been little-studied in this species.

Home Range

Exact size of territory needed for a single individual is unreported and the habitat size requirements need further study. Adult frogs travel between nearby breeding pools during the rainy season. (Duellman and Morales, 1990; Murphy, 1999)

Communication and Perception

Perez’s snouted frogs are vocal communicators, a behavior typical in most anurans. Males vocalize the most and can produce a variety of calls, usually from the edge of the chosen breeding pond or water-filled cavity. They produce a distinct advertisement call to attract females to their nesting site and to make their presence known to other calling males. The call has been described (Bartlett and Bartlett 2003) as four to five short whistled notes. Advertisement calling can be heard during the day and night. They also produce a separate courtship call right before mating occurs (Schlüter, 1990). (Bartlett and Bartlett, 2003; Duellman and Morales, 1990; Schlüter, 1990)

Food Habits

No specific research on feeding habits of adult Perez's snouted frogs has been reported. A closely related species, Physalaemus albonotatus (also in the family Leptodactylidae), that occupies a range farther east in Amazonia, is an opportunistic insectivore. Larger adults tend to prey on larger insects and are found to consume more prey in general than smaller adults and juveniles (Falico et al, 2012). Perez's snouted frogs most likely exhibit similar feeding behavior, as insectivory is a common behavior in most anurans. Living solely on the forest floor, they most likely forage in leaf litter and near fallen trees, as this is where they are most commonly found in the field. Tadpoles are herbivorous and eat plant material in temporary breeding pools (Murphy, 1999). (Duellman and Morales, 1990; Falico, et al., 2012; Murphy, 1999)

  • Animal Foods
  • insects
  • terrestrial non-insect arthropods

Predation

Tadpoles are heavily preyed on by insect larvae that often share their pools. Adult, aquatic insects, and rarely vertebrates will also prey on Perez's snouted frog tadpoles (Murphy, 1999). Being a small, presumably non-toxic vertebrate, they likely have many predators in their habitat, perhaps including snakes, birds, and mammals. Their cryptic coloration makes Perez's snouted frogs well-suited to hide from predators. Their leaf-shaped bodies allows for excellent camouflage on the forest floor. (Bartlett and Bartlett, 2003; Murphy, 1999)

  • Anti-predator Adaptations
  • cryptic
  • Known Predators
    • hawker dragonflies (g. Aeshna)
    • skimmer and percher dragonflies (g. Tramea)
    • giant water bugs (g. Belostoma)
    • whirligig beetles (Gryinidae)
    • backswimmers (Buenoa)
    • diving beetles (Dystiscidae)

Ecosystem Roles

Perez's snouted frogs function as small insectivorous predators of the leaf litter community in the rainforest. In turn, they are eaten by larger predators and undoubtedly have internal parasites, but no specific research on energy consumption or contribution was found.

Economic Importance for Humans: Positive

These frogs are presumably beneficial and probably eat insects that may be human pests, but are likely not sufficiently common to have a significant effect.

  • Positive Impacts
  • controls pest population

Economic Importance for Humans: Negative

Perez's snouted frogs are harmless to human interests.

Conservation Status

Perez's snouted frogs have a very wide distribution in western Amazonia and the species as a whole appears to be under no dire threats to extinction. They are a tolerant group of frogs and can survive some habitat disturbances, being found both in primary and secondary forests. Localized populations are in decline in areas of agriculture and logging. (Angulo, et al., 2004; Bartlett and Bartlett, 2003)

Contributors

Kelsey Bowe (author), Michigan State University, James Harding (editor), Michigan State University.

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.

diurnal
  1. active during the day, 2. lasting for one day.
ectothermic

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

external fertilization

fertilization takes place outside the female's body

fertilization

union of egg and spermatozoan

herbivore

An animal that eats mainly plants or parts of plants.

heterothermic

having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.

insectivore

An animal that eats mainly insects or spiders.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

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.

mountains

This terrestrial biome includes summits of high mountains, either without vegetation or covered by low, tundra-like vegetation.

native range

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

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

phytoplankton

photosynthetic or plant constituent of plankton; mainly unicellular algae. (Compare to zooplankton.)

polygynandrous

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

polymorphic

"many forms." A species is polymorphic if its individuals can be divided into two or more easily recognized groups, based on structure, color, or other similar characteristics. The term only applies when the distinct groups can be found in the same area; graded or clinal variation throughout the range of a species (e.g. a north-to-south decrease in size) is not polymorphism. Polymorphic characteristics may be inherited because the differences have a genetic basis, or they may be the result of environmental influences. We do not consider sexual differences (i.e. sexual dimorphism), seasonal changes (e.g. change in fur color), or age-related changes to be polymorphic. Polymorphism in a local population can be an adaptation to prevent density-dependent predation, where predators preferentially prey on the most common morph.

rainforest

rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.

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

tactile

uses touch to communicate

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

year-round breeding

breeding takes place throughout the year

References

Angulo, A., C. Azevedo-Ramos, L. Coloma, S. Ron. 2004. "Edalorhina perezi" (On-line). The IUCN Red List of threatened species. Accessed December 04, 2014 at http://www.iucnredlist.org/details/full/56385/0.

Bartlett, R., P. Bartlett. 2003. Reptiles and Amphibians of the Amazon. Gainesville: University Press of Florida.

Cope, E. 1874. On Some Batrachia and Nematognathi Brought from the Upper Amazon by Prof. Orton. Proceedings of the Academy of Natural Sciences of Philadelphia, 26: 120-137.

Duellman, W., V. Morales. 1990. Variation, Distribution, and Life History of Edalorhina perezi (Amphibia, Anura, Leptodactylidae). Studies on Neotropical Fauna and Environment, 25: 19-30.

Dunn, E. 1949. Notes on the South American Frog Genus Edalorhina. American Museum Novitates, 1416: 1-10.

Falico, D., . López, C. Antoniazzi, A. Beltzer. 2012. Interpopulation and ontogenetic variation in the diet of the menwig frog Physalaemus albonotatus (Anura: Leiuperidae). Revista mexicana de biodiversidad, 83/4: 1187-1193.

Murphy, P. 2003. Context-dependent reproductive site choice in a Neotropical frog. Behavioral Ecology, 14/5: 626-633.

Murphy, P. 1999. The Interplay Between Uncertain Juvenile Recruitment and Reproductive Strategy in the Neotropical Frog Edalhorina perezi. Duke University: Department of Zoology, Duke University.

Schlüter, A. 1990. Reproduction and Tadpole of Edalorhina perezi (Amphibia, Leptodactylidae). Studies on Neotropical Fauna and Environment, 25: 49-56.

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