Species Description: SPIX, J.B., 1824 - Animalia Nova Sive Species Novae Testudinum et Ranarum Quas in Itinere per Brasiliam Annis MDCCCXVII-MCCCCXX Jussu et Auspidis Maximiliani Joseph I. Bavarie Regis. Monachii: S. Hübschmanni.
Taxonomic Notes: Rhinella ornata Spix 1824. Removed from synonymy of Rhinella (Bufo) crucifer by Baldiserri, Caramaschi and Haddad 2004, Arquivos do Museu Nacional. Rio de Janeiro 62:255-282.
Description Rhinella ornata is a robust, medium-sized toad characterized by a snout-vent length range of 54.5 - 76.4 mm in males and 60.4 - 88.1 in females. Their head is wider than long and is easily distinguished from the body in the dorsal view. In the dorsal view, the snout is rounded to sub-elliptical and in the lateral view it is sub-acute. The nostrils are protuberant and the area between them is flat with a distance that is approximately the same length as the diameter of the tympanum. The canthal ridge is straight, and the loreal region is concave. The distance from eye to nostril is about 73% of the eye diameter. The protuberant eyes have moderate pre-orbital ridges. The width of the toad’s upper eyelid is 65% of the interorbital distance. The distance between the toad’s eye and distinct tympanum is 1.0 - 3.5 mm. When the supratympanic ridge is present the tympanum is elliptical, but if not, it is circular. The species has moderate cranial crests and the top of the head is depressed, forming a concave region with the orbital ridges. The oval parotids do not extend past the lateral edges of the body in the dorsal view and are not subdivided. There is a lateral row of tubercles that connect to the parotoid gland. There is also a row of keratinized tubercles connecting the corner of the mouth and the insertion of the arm. The forelimbs are long with the robust forearm being shorter than the upper arm. The hands are large. The inner carpal tubercle is slightly elevated, keratinized, and elliptical. The outer metacarpal tubercle is flat and can range from triangular, circular, or elliptical. The long fingers are slightly fringed, but have no webbing, and their relative lengths are II ≈ IV < I < III. The subarticular tubercles are well-defined, rounded, and elevated. The length of the thigh is shorter than the tibia and together the hind limb is about 86% of the snout-vent length. The elevated inner metatarsal tubercle is elliptical and the outer metatarsal tubercle is rounded. A row of small tubercles, which do not form a fringe, can be found starting near the inner metatarsal tubercle and extending along the foot to the tibia-heel articulation. The long toes have a relative length of I < II < V < III < IV and basal webbing with a formula of I 1 - 2 II 1 ½ - 3 III 2 ½ - 4 IV 4 - 2 V. The toes also possess small, elevated subarticular tubercles. Males have a moderately developed, single, subgular vocal sac (Baldissera et al. 2004).
DIAGNOSIS:
Rhinella ornata has a shorter snout-vent length than the morphologically similar R. crucifer and R. pombali. Rhinella ornata has an average snout-vent length of 63.6 mm versus 81.6 mm in R. crucifer, and 73.3 mm in R. pombali. However, R. ornata has a longer snout-vent length than R. henseli, whose average snout-vent length is 58.3 mm. Furthermore, R. crucifer has parotoid glands that overhang the dorsal edge of the body, but R. ornata lacks these overhanging glands. The elliptical shape of the parotoid glands further differentiates R. ornata from the more narrow and long shape in R. henseli. The moderate cranial crests found in R. ornata also differentiate it from R. henseli. Rhinella ornata lacks fringe on the ventral surface of the tarsus, which are present in R. crucifer and R. pombali, instead having a row of distinct tubercles. The presence of these tubercles also differentiate R. ornata from R. henseli, which have tiny tubercles. Lastly, the lack of yellow spots near the cloaca and on the posterior thigh in R. ornata differentiates it from R. crucifer, R. henseli and R. pombali, all of which have spots (Baldisseri et al. 2004).
COLORATION:
In life, the dorsal side R. ornata of varies from an ochre to olive to dark brown and sometimes even a brick red. If there is a brick red coloring to the dorsal side, then R. ornata will appear almost velvet-like in texture. There is always a vertebral line, which begins in the rostral region and terminates at the urostyle, but the line can range from thin to thick and vary in color from a yellow to a deep orange or almost brown. If the line is thicker than usual, it is accompanied by symmetrical black markings outlining the vertebral line. Transverse stripes are present on the limbs, especially on the forelimbs. The ventral area varies from ochre to cream with sprinkles of orange, yellow, or gray marks that become fainter towards the thighs. When R. ornata is preserved the dorsal coloration is dark olive or dark beige and the vertebral line becomes faint. A light colored, hazy sub-ocular band, which may form a triangle, is also visible. The subgular vocal sac may become a darker gray than the abdomen in some males (Baldissera et al. 2004).
VARIATION:
Rhinella ornata is highly polymorphic, leading to several synonymies and taxonomic challenges (see comments section). The dorsal color varies from an olive to dark brown and sometimes even a brick red. The ventral color range from a deep orange or yellow to gray dots. In males, the subgular region tends to be a darker color than in the females (Baldissera et al. 2004). Rhinella ornata also shows examples of island dwarfism. Populations on the mainland, Seropédica, of the State of Rio de Janeiro, Brazil have a larger snout-vent length than species on islands surrounding the mainland. The island farthest away, Ilha Grande, has the smallest individuals of R. ornata (Montesinos et al. 2011). In addition, populations on Ilha Grande reach sexual maturity earlier than populations on the mainland (Reboucas et al. 2019).
Rhinella ornata has a fairly limited range. The species can be found in lowland Atlantic rainforest, ranging from the Brazilian State of Espirito Santo to the northern State of Rio Grande do Sul and west to Paraná State. The species can also be found in northeastern Argentina contained within the provinces of Missions and Corrientes. The species can be found in forested and disturbed edges of forests (Baldissera et al. 2004), but can also be found in mixed agricultural and forested areas (IUCN 2023). Rhinella ornata also lives on the mainland and land-bridge islands in the State of Rio de Janeiro (Montesinos et al. 2011). Some of the toad populations are isolated due to the removal of the land-bridges to the islands. This species is most often found in the leaf litter of the forest (Maia-Carneiro et al. 2011) and typically resides in forests and inland wetlands from about sea level to 1,000 m in elevation (Baldissera 2010).
Life History, Abundance, Activity, and Special Behaviors Rhinella ornata can be found in different forest microhabitats, but generally occupy the leaf litter. As a terricolous species, R. ornata is somewhat dependent on forested areas (Maia-Carneiro et al. 2011).
This toad tends to be most active at night, owing to the avoidance of warm temperatures and low humidity during the day. Despite this, some juveniles can be active during the daytime (Maia-Carneiro et al. 2011).
Rhinella ornata consumes a range of prey items, primarily insects and is likely an opportunistic foragers whose diets vary with prey availability (Maia-Carneiro et al. 2011).
Rhinella ornata is preyed on by introduced red swamp crayfish (Procambarus clarkii) during the reproductive season has been documented at the Lymington Foundation reserve in the Atlantic Forest at Juquitiba, São Paulo (Banci et al. 2013).
Larva The tadpoles of R. ornata are small, as is characteristic of the family Bufonidae (Fernandez and de Oliveira 2017).
High species richness in their habitat subjects tadpoles to a variety of predators (Fernandez and de Oliveira 2017).
Trends and Threats Rhinella ornata is of “Least Concern” on the IUCN Red List because of its wide range and tolerance to some habitat modification (IUCN 2023). However it is still threated by urbanization, the harvesting of non-timber crops, plantation conversion, livestock farming, and logging. Conservation sites are identified over the entire range (Baldissera 2010, IUCN 2023).
Relation to Humans Rhinella toad venom is used as a traditional medicine to treat cancer and skin infections in Paraguay. Specifically, R. ornata, R. scitula, and R. schneideri venom modifies the cell cycle proliferation, which affects the increase of cancer cells (Schmeda-Hirschmann et al. 2017).
Possible reasons for amphibian decline
General habitat alteration and loss Habitat modification from deforestation, or logging related activities Intensified agriculture or grazing Urbanization
Comments Parsimony and Maximum Likelihood analyses of 4474 base pairs of mtDNA and 3631 base pairs of nDNA were performed, with the two types of DNA independently and together to identify nuclear-mitochondrial discordance that may have arisen due to hybridization and introgression in the genus. Further analyses also included morphological data. These analyses found that R. ornata was sister to R. inopina with the next closest species being R. crucifer. However, the support for R. ornata being monophyletic was weak (Pereyra et al. 2021).
Rhinella ornata has gone through several taxonomic changes and because of its polymorphic character has had several species synonymized with it. The species was first named Bufo ornatus in 1824 by J.B. Spix, however, because of the taxonomic confusion with several South American toads, many were synonymized with Bufo crucifer. Baldissera et al. (2004) revalidated R. ornata (then as Bufo ornatus) based on morphological evidence and described two more species as B. abei and B. pombali. However, molecular and morphological evidence later combined R. abei into R. ornata and found that R. pombali was a hybrid of R. crucifer and R. ornata (Thomé et al. 2010, 2012, Pereyra et al. 2021). As of 2021, it’s unclear if R. pombali is a species of hybrid origin or should just be considered hybrids of the parental species (Pereyra et al. 2021).
Video from Amphibians of Rio Claro Farm by Fabio Maffei and Flavio Ubaid (2014):
For additional resources see:
Costa, F.R., Moura, P.H.A.G., and Nunes, I. (2020). On the courtship, breeding behaviour and vocalisation of Rhinella ornata (Spix, 1824) (Anura, Bufonidae): a well-marked escalated behaviour in a lek-like system. acta ethol 23, 69–77.
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Neto, A.P., and Bertoluci, J. (2021). Rhinella icterica and Rhinella ornata (Anura: Bufonidae) tadpoles do not recognise siblings. The Herpetological Journal 31(October 2021), 214-220.
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References Baldissera, F. A., Caramaschi, U., and Haddad, C. F. B. (2004). Review of the Bufo crucifer species group, with descriptions of two new related species (Amphibia, Anura, Bufonidae). Arquivos do Museu Nacional, 62(3), 255-282.
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Banci, K. R. S., Torello Viera, N. F., Marinho, P. S., de O. Calixto, P., and Marques, O. A. V. (2013). Predation of Rhinella ornata (Anura, Bufonidae) by the alien crayfish (Crustacea, Astacidae) Procambarus clarkii (Girard, 1852) in Sao Paulo, Brazil. Herpetology Notes, 6, 339-341.
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Fernandez, J.M.C., and de Oliveira, M.Z.T. (2017). Predation and schooling influence on the primary response of individuals of Rhinella ornata (Spix, 1824) (Anura: Bunonidae): an experimental assessment of habitat selection. South American Journal of Herpetology, 12(1), 57-60.
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Baldissera, F. 2010. Rhinella ornata. The IUCN Red List of Threatened Species 2010: e.T61754A12554682. https://dx.doi.org/10.2305/IUCN.UK.2010-2.RLTS.T61754A12554682.en. Downloaded on 17 February 2020.
Maia-Carneiro, T., Kiefer, M. C., Van Sluys, M., and Rocha, C. F. D. (2013). Feeding habits, microhabitat use, and daily activity period of Rhinella ornata (Anura, Bufonidae) from three Atlantic rainforest remnants in southeastern Brazil. North-Western Journal of Zoology, 9(1), 157-165.
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Montesinos, R., Ricardo da Silva, H., and Gomes de Carvalho, A. L. (2011). The ‘Island Rule’ acting on anuran populations (Bufonidae: Rhinella ornata) of the Southern Hemisphere. Biotropica, 44(4), 506-511.
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Pereyra, M. O., B. L. Blotto, D. Baldo, J. C. Chaparro, S. R. Ron, A. J. Elias-Costa, P. P. Iglesias, P. J. Venegas, M. T. C. Thomé, J. J. Ospina-Sarria, N. M. Maciel, M. Rada, F. Kolenc, C. Borteiro, M. Rivera-Correa, F. J. M. Rojas-Runjaic, J. Moravec, I. De la Riva, W. C. Wheeler, S. Castroviejo-Fisher, T. Grant, C. F. B. Haddad, and J. Faivovich. (2021). Evolution in the genus Rhinella: A total evidence phylogenetic analysis of Neotropical True Toads (Anura: Bufonidae). Bulletin of the American Museum of Natural History 447(1), 1–156.
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Reboucas, R., de Silva, H.R., Sanuy, D., and Solé, M. (2019). Sexual maturity and growth of male toads (Rhinella ornata): a comparison between Insular and mainland Populations. Zoologischer Anzeiger, 283, 12-19.
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Schmeda-Hirschmann, G., Gomez, C. V., Rojas de Arias, A., Burgos-Edwards, A., Alfonso, J., Rolon, M., Brusquetti, F., Netto, F., Urra, F. A., and Cardenas, C. (2017). The Paraguayan Rhinella toad venom: implications in the traditional medicine and proliferation of breast cancer cells. Journal of Ethnopharmacology, 199, 106-118.
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Thomé, M.T.C., K.R. Zamudio, Giovanelli, J.G.R., Baldissera Jr., F.A., Haddad, C.F.B., and Alexandrino, J. (2010). Phylogeography of endemic toads and Post-Pliocene persistence of the Brazilian Atlantic Forest. Molecular Phylogenetics and Evolution 55(3), 1018–1031.
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Thomé, M.T.C., Zamudio, K.R., Haddad, C.F.B., and Alexandrino, J. (2012). Delimiting genetic units in Neotropical toads under incomplete lineage sorting and hybridization. BMC Evolutionary Biology 12, 242.
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Species Account Citation: AmphibiaWeb 2024 Rhinella ornata <https://amphibiaweb.org/species/6832> University of California, Berkeley, CA, USA. Accessed Dec 25, 2024.
Map of Life