Description
The species was described from an adult male holotype and two juvenile specimens. The snout-vent length in the adult male is 41 millimeters, and 23 millimeters and 36 millimeters in the two juveniles. The pointed head is square. The rostrum is flat but extends out over the mouth. It has no obvious cranial ridges, but it does have a temporal crest that stretches from the eye to the parotoid gland. The tympanum is not visible and the sub-triangular parotoids are about the same size as the eyes. It has a toothlike ridge on the sides of its back. Its fingers are webbed up to the metacarpals, with the first finger half as long as the second finger. No information on the relative digit lengths is available. The toes are about three-fourths webbed, but the webbing reaches different areas on each toe. There are two metatarsal tubercules per foot, with the inner tubercule larger than the outer. The dorsal side of is covered in tubercules, including the dorsal surface of the legs (Noble 1920).

Rhinella rostrata was originally thought to be closely related to Incilius coniferus (originally Bufo coniferous). Incilius coniferus has a different snout shape, a visible tympanum, and its digits have more webbing. The closest related species is now believed to be Rhinella truebae, originally named Rhamphophryne truebae. There are three major differences between the two species: ear morphology, vertebral counts, and sacrococcygeal articulation. The tympanum of R. truebae is visible, specifically from the ventral side. Rhinella truebae also has eight presacral vertebrae and the sacrum is combined with the coccyx to produce the sacrococcygeal articulation (Noble 1920, Lynch and Renjifo 1990).

In life, it is yellowish brown with dark brown markings that appear as crossbands on the legs. The frog has a yellowish white coloring with a dark brown reticulation on the ventral side. (Noble 1920).

Variation in this species is not well studied due to the low number of specimens found in the field. One juvenile specimen differed from the rest of the specimens in having an especially sharp canthus rostralis. Both of the smaller individuals have redder and less yellow coloring overall than the adult male holotype (Noble 1920).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Colombia

View distribution map in BerkeleyMapper.

All specimens of this species were found in the southern part of the Department of Antioquia, Colombia. Rhinella rostrata is located at the Santa Rita Creek, which is fourteen miles north of Mesopotamia at 2,472 meters above sea level. Santa Rita Creek is considered the frogs’ only habitat as not enough specimens have been found (Noble 1920, Bolivar and Lynch 2004).

Life History, Abundance, Activity, and Special Behaviors
Rhinella rostrata is considered a terrestrial species. Unlike many other species of frogs, R. rostrata is considered to be viviparous, not oviparous. Other reproductive behaviors cannot be determined because of an insufficient amount of specimens (Graybeal and Cannatella 1995).

Trends and Threats
Only two (Bolivar and Lynch 2004) or three (Noble 1920) individuals of this species have been found since 1914. Rhinella rostrata is extremely rare and may even be extinct. Threats include logging, increasing human populations, introduced plant species such as illegal crops, and the repercussions of trying to maintain the introduced species (Noble 1920, Bolivar and Lynch 2004).

Possible reasons for amphibian decline

Habitat modification from deforestation, or logging related activities
Urbanization
Local pesticides, fertilizers, and pollutants

Comments
The species authority is: Noble, G.K. 1920. Two new Batrachians from Colombia. Bulletin of the American Museum of Natural History 42(9): 441-446.

Rhinella rostrata is a sister species to Rhinella truebae. Rhinella rostrata was originally ascribed the genus name “Bufo”, and subsequently the genus name “Rhamphophryne” (Lynch and Renjifo 1990).

Rhinella comes from the Greek words “rhinos” and “ella” and translates into “little nose” (Dodd 2013). The species name rostrata has not been defined by the species authority, but comes from the Latin word “rostratus” which translates to “having a beak, hooked, with a crooked point” (Lewis 1890).

References

Bolivar, W. and Lynch, J. 2004. Rhinella rostrata. The IUCN Red List of Threatened Species. Version 2014.3. iucnredlist.org.

Dodd, C. K. 2013. Frogs of the United States and Canada. John Hopkins University: JHU Press.

Graybeal, A., Cannatella, D.C. (1995). ''A new taxon of Bufonidae from Peru, with descriptions of two new species and a review of the phylogenetic status of supraspecific bufonid taxa.'' Herpetologica, 51(2), 105-131.

Lewis, C. T. 1890. An Elementary Latin Dictionary. New York, Cincinnati, and Chicago. American Book Company.

Lynch, J. D. and Renjifo, J.M. (1990). ''Two new toads (Bufonidae: Rhamphophryne) from the Northern Andes of Colombia.'' Journal of Herpetology, 24(4), 364-371.

Noble, G. K. 1920. Two new Batrachians from Colombia. Bulletin of the American Museum of Natural History 42.9: 441-446.

Species Account Citation: AmphibiaWeb 2015 Rhinella rostrata: Mesopotamian Beaked Toad <https://amphibiaweb.org/species/417> University of California, Berkeley, CA, USA. Accessed May 7, 2025.

Citation: AmphibiaWeb. 2025. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 7 May 2025.

AmphibiaWeb's policy on data use.