Description
[Description originally from Rhinella jimi, now a synonym of R. diptycha (Pereyra et al. 2021).]

This is a large, stout toad with a snout-vent length of approximately 147 mm (standard deviation of 16.34) in males and 134 mm (standard deviation of 29.71) in females. The body of is wider than long, with a rounded snout when viewed from the side and exhibits a semicircular shape when viewed ventrally. The head is very wide and has thick and discernible cranial crests. The cranial crest on the snout is similarly thick and somewhat projected from the snout. The nostrils are protuberant and directed posteriorly towards the back of the head. There are short, thick arcs above the lips. The canthal ridge is distinct, and the loreal region protrudes slightly. The eyelids are thick with projected edges and keratinized spines along the edges. It has a distinctly rounded tympanum with a few keratinized points. There are parotoid glands behind the supra-tympanic crests; these crests are broad when viewed from the front but are slender when viewed from behind. Elongated tubercles are situated behind each parotoid gland, and these tubercles reach to the median inguinal region. The dorsal surface has many tubercles of varying sizes, and there are keratinized spines on the skin. On males, these points have small spines and make the skin feel similar to sandpaper; females do not have these spines and feels smoother. There are two visible clusters of glands on both sides of the cloaca that are present on every individual. Males have strong, somewhat wide arms, whereas females have slimmer arms. This species has well-defined forearm glands when viewed dorsally. They have rounded inner metacarpal tubercles. The larger outer metacarpal tubercle is also rounded, and followed by a line of smaller, slightly keratinized tubercles along the ventral surface of the forearms. The species has no finger webbing, and their relative lengths are as follows: III > IV > I > II. The fingers have divided subarticular tubercles. The legs are short and thick with hard-to-define, irregular tibiae glands. The metatarsal fold is low, thick, and covered by a line of keratinized points. The feet are longer than wide with an oval-shaped inner metatarsal tubercle. The feet have a main, well-defined gland that reaches to the fifth toe when viewed from the side; in addition, there’s a less-defined gland within the metatarsal region. The toes are webbed proximally, but are distally fringed. The toe lengths are as follows: IV > III > V > II > I. The singular subarticular tubercles are small and rounded (Stevaux 2002).

Rhinella icterica does not have the tibial glands that R. diptycha does, but they share similar osteological, reproductive, and morphological traits. Rhinella marina and R. poeppigii represent a more basal clade, and, along with R. rubescens and R. arenarum, have smaller parotoid glands and more elongated skulls (Stevaux 2002).

In preservation, the dorsum of R. diptycha is a grayish-beige and dappled with almost-symmetrical dark brown spots from the parotoid glands to the posterior region on both sides of the body. The parotoid glands appear orange. While most of the body is beige, the ventral surface is lighter than the dorsum. The head is very dark, and is almost black in some individuals. Brown spots are more concentrated around the head and are scarcely present along the back (Stevaux 2002).

The species displays sexual dimorphism. Males have spines on the keratinized spikes on their skin, while females do not. This is most evident in the smoother skin texture of females (Stevaux 2002).

In the original description of Rhinella jimi, Stevaux (2002) noted that it is likely a species within the Rhinella schneideri species complex, which is largely distributed around South America. Rhinella jimi is sympatric with R. schneideri in the northeastern region of Brazil, but they clearly represent differentiated species. Because both R. jimi and R. schneideri both have tibial glands and a similar parotoid gland shape, implying a close phylogenetic relationship. However, R. jimi has a forearm gland, an external gland on its feet, and gland conglomerates on either side of its cloaca, all of which are absent in R. schneideri. Rhinella jimi has slightly shorter eyelids, a smaller eye diameter, smaller hands, and a slightly larger metatarsal fold length (Stevaux 2002).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Argentina, Bolivia, Brazil, Paraguay, Uruguay

	View distribution map in BerkeleyMapper.
	View Bd and Bsal data (3 records).

Rhinella diptycha can be found across the entire northeastern region of Brazil at low altitudes (from sea level to 500 m). Rhinella diptycha has been specifically found between the State of Maranhão to the State of Bahia. The species can be found in the northern rainforest areas along the Atlantic coast, in the areas of caatinga (a type of vegetation found in deserts) in Maracás, and in the dry areas of Cabaceiras in Paraíba (Stevaux 2002).

Life History, Abundance, Activity, and Special Behaviors
As R. jimi, Rhinella diptycha is reported to breed in both permanent and temporary ponds (Andrade and Carnaval 2004).

Rhinella diptycha stores bufotoxins in its parotoid glands; when ingested, these toxins can cause paralysis, tremors, and death in predators. One of the main predators is Athene cunicularia, a burrowing owl that can be found in North and South America. Because there have been few other observed predators of Cope's Toad, it is thought that its bufotoxins are an effective defensive mechanism (Protázio et. al 2011).

Trends and Threats
The current IUCN status of Rhinella diptycha is “Data Deficient” and the IUCN status lists no current threats to this species (Andrade and Carnaval 2004; Scott et al 2004). However, one danger facing its synonymized Rhinella jimi population is railroad collisions. Railroad segments pass through the Amazon in Brazil, but it is otherwise an undisturbed landscape. Researchers found a variety of toad carcasses along the railroad tracks, including R. jimi. While some of the individuals died from direct train collisions, others were killed by barotrauma. Barotrauma occurs when moving trains quickly change the air pressure around the toad, pushing air against them and fatally pushing their stomachs through their mouths. Some smaller toad carcasses were found dried out along the tracks. This is likely due to their inability to cross the tracks and find a suitably moist shelter. Toads are most vulnerable to railroad deaths during their migration period between the dry and wet seasons. The researchers found that railroads result in over 10,000 railroad fatalities annually (Dornas et al. 2019).

Current conservation efforts in Brazil include designated conservation sites and protected areas of R. diptycha's habitats (Andrade and Carnaval 2004).

Relation to Humans
See Threats above.

Possible reasons for amphibian decline

Disturbance or death from vehicular traffic

Comments
In 2021, Pereyra et al. reviewed the entire genus Rhinella presenting comprehensive datasets in a phylogenetic analysis. By implication from several previous works, Rhinella diptycha includes the synonyms: Rhinella jimi (Pereyra et al. 2021), Rhinella schneideri (Chaparro et al 2007), Bufo pisanoi (Casamiquela 1967); but see Amphibian Species of the World for complete bibliography (link at top left).

This species was featured in News of the Week October 18, 2021:

Amphibians are known for their very permeable skin that functions in gas and water exchange. Frogs, in particular, have colonized very dry habitats worldwide that would create seemingly conflict between the need for oxygen uptake (required for metabolism) and water loss (potential desiccation). To better understand how frogs, and especially their skin, cope with dry habitats, Mailho-Fontana et al. (2021) compared the skin, physiology, and behavior of two closely related toad species, the Yellow Cururu Toad and Cope's Toad (Rhinella icterica and R. jimi, which is now known as R. diptycha, respectively) that experience different climates. The authors found that the Cope's Toad from drier climate regions had thicker and more glandular skin, showed lower rates of water loss and displayed stereotyped behaviors to increase water uptake when dehydrated. These findings link differences in form, function, and behavior to illuminate strategies for desiccation resistance in frogs. (MWomack)

References

Andrade, G., Carnaval, A. C. (2004). “Rhinella jimi.” The IUCN Red List of Threatened Species 2004: e.T54674A11184744. https://dx.doi.org/10.2305/IUCN.UK.2004.RLTS.T54674A11184744.en. [link]

Casamiquela, R. M. (1967). "Sobre un nuevo Bufo fósil de la provincia de Buenos Aires (Argentina)." Ameghiniana. Buenos Aires, 5, 161–168.

Chaparro, J. C., J. B. Pramuk, and A. G. Gluesenkamp (2007). "A new species of arboreal Rhinella (Anura: Bufonidae) from cloud forest of southeastern Peru." Herpetologica, 63, 203–212.

Dornas, R. A.P., Teixeira, F.Z., Gonsioroski, G., Nóbrega, R.A.A. (2019). ''Strain by the train: Patterns of toad fatalities on a Brazilian Amazonian railroad.'' Science of The Total Environment, 660, 493-500. [link]

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, 1–156. [link]

Protázio, A., Carvalho, S., Protázio, A., Mesquita, D. (2011). ''Rhinella jimi (Cururu Toad) Predation.'' Herpetological Bulletin, 118, 40-41. [link]

Scott, N., Aquino, L., Angulo, A. 2004. Rhinella diptycha. The IUCN Red List of Threatened Species 2004: e.T54628A11177973. https://dx.doi.org/10.2305/IUCN.UK.2004.RLTS.T54628A11177973.en. Downloaded on 15 July 2021.

Stevaux, M. N. (2002). ''A new species of Bufo Laurenti (Anura, Bufonidae) from northeastern Brazil.'' Revista Brasileira de Zoologia, 19, 235–242. [link]

Species Account Citation: AmphibiaWeb 2021 Rhinella diptycha: Cope's Toad <https://amphibiaweb.org/species/162> University of California, Berkeley, CA, USA. Accessed Nov 24, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 24 Nov 2024.

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