Calyptocephalella

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Calyptocephalella
Temporal range: Maastrichtian–Recent
Calyptocephalella gayi foto.jpg
Calyptocephalella gayi
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Amphibia
Order: Anura
Family: Calyptocephalellidae
Genus: Calyptocephalella
Strand, 1928
Species:
C. gayi
Binomial name
Calyptocephalella gayi
(Duméril & Bibron, 1841)
Calyptocephalella gayi.svg
Range in red
Synonyms
  • Caudiverba caudiverba

Calyptocephalella is a genus of frogs in the family Calyptocephalellidae. It is represented by a single living species, Calyptocephalella gayi, commonly known as the helmeted water toad, Chilean helmeted bull frog, or wide-mouthed toad. Additionally, there are a few extinct species that are only known from Late Cretaceous and Paleogene fossil remains from Patagonia in South America and the Antarctic Peninsula (at times when it was warmer and wetter). [2] [3] The helmeted water toad living today is aquatic to semi-aquatic, and found in deep ponds and reservoirs in central Chile and possibly adjacent west-central Argentina. [1] [4]

Contents

This very large toad typically weighs up to 0.5–1 kg (1.1–2.2 lb), but sometimes considerably more. It is the world's second largest frog after the goliath frog. [5] It is threatened by capture for human consumption, habitat loss, pollution, introduced species and the disease chytridiomycosis. It is often kept in herpetoculture, mostly locally where it is farmed for food, but also in other countries as a pet. [1]

Characteristics

Brown individual; the color of this species is quite variable Calyptocephallela gayi02.jpg
Brown individual; the color of this species is quite variable

The helmeted water toad is a robust species with a broad head and large mouth. [6] It is very large, and can reach a snout–to–vent length of up to 15.5 cm (6.1 in) in males and 32 cm (12.6 in) in females. [4] [7] The typical maximum weight is 0.5–1 kg (1.1–2.2 lb), [8] [9] but exceptionally large individuals can reach 3 kg (6.6 lb). [1] Such giants are essentially unheard of today, although there are recent records of several individuals weighing 1.2–1.3 kg (2.6–2.9 lb). [10] [11] It is the largest anuran (frogs and toads) of the Americas, surpassing other large species like the Blomberg's, cane, Colorado River, cururu and smooth-sided toads, and the American bull-, Lake Junin, mountain chicken and Titicaca water frogs. [6] The maximum snout–to–vent is similar to that of the world's largest frog, the African goliath frog (Conraua goliath), which however can weigh more. [12] Helmeted water toads are colored yellow, brown and green, with light green in mature specimens, while the oldest are gray, or have gray patches on a dark background. The olive-brown to dusky tadpoles also grow unusually large, typically exceeding lengths of 10 cm (3.9 in) and reaching up to 15 cm (5.9 in). [4] [9]

Behavior

Reproduction and aggressive behavior

The helmeted water toad breeds in the South Hemisphere spring (September–October) when males call. [6] The female lays between 1,000 and 16,000 eggs in shallow, well-vegetated water. [6] [7] Although many eggs never hatch, captive studies have shown that a single spawning may result in more than 1,000 tadpoles. [7] Typical larval (tadpole) life lasts five months to a year, but up to two years. [6] [9] After hatching, larval survival depends on the presence of vegetation as the existence of movements in the body of water maintain good oxygenation, but the presence of seasonal ponds with some degree of drainage is essential for hatching, as these sites contain fewer predators to the larvae. Then, the transport of larvae from ponds, to larger bodies of water during the rains, or transport of these among several bodies of water facilitates the survival and allows a good development of populations. The larvae prefer cooler areas of the body of water and protective aquatic vegetation, unlike toad larvae that occupy the same sites and have a higher degree of pigmentation that protects them from the solar rays.[ citation needed ] While the species is almost entirely aquatic, especially young helmeted water toads that are recently metamorphosed from the tadpole stage often can be seen on land. [13] In captivity, they can breed when 2 years old and a female was able to breed until 24 years old. [1]

The helmeted water toad is quite aggressive and it has an aggressive call specifically directed at other individuals of the same species. During encounters with conspecifics they inflate their body, open their large mouth and may jump forward towards an opponent. The same behavior can be directed at potential predators, including humans, although they may choose to escape silently by diving into the water. [13]

Feeding

Their food in the tadpole stage is vegetation and detritus. [9] Adults feed on virtually any animal they can overpower and swallow, including fish, invertebrates, small birds, small mammals and other frogs. [4] [6] Cannibalism also occurs. [13]

Conservation status

The helmeted water toad is a vulnerable species according to IUCN due to capture for human consumption (to a lesser degree also to supply the pet trade), habitat loss, pollution, introduced species (especially trout and African clawed frog) and the disease chytridiomycosis (caused by Batrachochytrium dendrobatidis ). [1] The species is kept in frog farms that supply the food market, but helmeted water toads take three years to reach a marketable size; they have been unable to produce enough to meet the demand and the farms have not been lucrative. [1] [14] Despite being illegal in Chile, wild caught individuals are still frequently sold for food in the country and control is insufficient. [14] International trade require a permit, as the species is listed on CITES Appendix III. [15]

On average, helmeted water toads experience water temperatures of about 10 °C (50 °F) in the winter and 20 °C (68 °F) in the summer. [16] While their tolerance is broader, [16] they already have an increased mortality rate at 25 °C (77 °F) and are entirely unable to cope with temperatures of c.30 °C (86 °F) or warmer. [7] [17] It is projected that a significant percentage of the population will disappear before the year 2100 due to global warming. [17] In some places where water levels have been greatly reduced due to a combination of climate change (drought) and extraction for agriculture, mass deaths of helmeted water toads have already been recorded. [7] [10]

It is also threatened by the introduction of the African clawed frog (known in Chile as the African toad), a species that has affected, as in other parts of the world, local amphibians when carrying the chytrid fungus Batrachochytrium dendrobatidis, which passes through the skin of amphibians not adapted to it. Their cells react to the pathogen, causing hardening and, therefore, hyperkeratosis and death by asphyxiation. The fungus has been classified as a major factor in the decline in amphibian populations worldwide, but in Chile has been reported recently, in 2009. Other causes cited are competition that occurs between African clawed frog and helmeted water toad, introduced for sale in the market for frog legs.

See also

Related Research Articles

<span class="mw-page-title-main">Amphibian</span> Class of ectothermic tetrapods

Amphibians are ectothermic, anamniotic, four-limbed vertebrate animals that constitute the class Amphibia. In its broad sense, it is paraphyletic group encompassing all tetrapods excluding the amniotes. All extant (living) amphibians belong to the monophyletic subclass Lissamphibia, with three living orders: Anura (frogs), Urodela (salamanders), and Gymnophiona (caecilians). Evolved to be mostly semiaquatic, amphibians have adapted to inhabit a wide variety of habitats, with most species living in freshwater, wetland or terrestrial ecosystems. Their life cycle typically starts out as aquatic larvae with gills known as tadpoles, but some species have developed behavioural adaptations to bypass this.

<span class="mw-page-title-main">Frog</span> Order of amphibians

A frog is any member of a diverse and largely carnivorous group of short-bodied, tailless amphibians composing the order Anura. The oldest fossil "proto-frog" Triadobatrachus is known from the Early Triassic of Madagascar, but molecular clock dating suggests their split from other amphibians may extend further back to the Permian, 265 million years ago. Frogs are widely distributed, ranging from the tropics to subarctic regions, but the greatest concentration of species diversity is in tropical rainforest. Frogs account for around 88% of extant amphibian species. They are also one of the five most diverse vertebrate orders. Warty frog species tend to be called toads, but the distinction between frogs and toads is informal, not from taxonomy or evolutionary history.

<span class="mw-page-title-main">Tadpole</span> Larval stage in the life cycle of an amphibian

A tadpole is the larval stage in the biological life cycle of an amphibian. Most tadpoles are fully aquatic, though some species of amphibians have tadpoles that are terrestrial. Tadpoles have some fish-like features that may not be found in adult amphibians such as a lateral line, gills and swimming tails. As they undergo metamorphosis, they start to develop functional lungs for breathing air, and the diet of tadpoles changes drastically.

<span class="mw-page-title-main">Common frog</span> Species of amphibian

The common frog or grass frog, also known as the European common frog, European common brown frog, European grass frog, European Holarctic true frog, European pond frog or European brown frog, is a semi-aquatic amphibian of the family Ranidae, found throughout much of Europe as far north as Scandinavia and as far east as the Urals, except for most of the Iberian Peninsula, southern Italy, and the southern Balkans. The farthest west it can be found is Ireland. It is also found in Asia, and eastward to Japan. The nominative, and most common, subspecies Rana temporaria temporaria is a largely terrestrial frog native to Europe. It is distributed throughout northern Europe and can be found in Ireland, the Isle of Lewis and as far east as Japan.

<span class="mw-page-title-main">Goliath frog</span> Species of amphibian

The goliath frog, otherwise known commonly as the giant slippery frog and the goliath bullfrog, is a species of frog in the family Conrauidae. The goliath frog is the largest living frog. Specimens can grow up to 32 centimetres (12.6 in) in length from snout to vent, and weigh up to 3.25 kilograms (7.2 lb). This species has a relatively small habitat range in Cameroon and Equatorial Guinea. Its numbers are dwindling due to habitat destruction, collection for food, and the pet trade.

<i>Telmatobufo</i> Genus of amphibians

Telmatobufo is a genus of frogs endemic to southern Chile. Their closest living relative is the monotypic helmeted water toad, Calyptocephalella gayi. These frogs were recently removed from the Leptodactylidae and placed in a new family, the Calyptocephalellidae. All three species of Telmatobufo that have been assessed by the IUCN are considered threatened.

<i>Conraua</i> Genus of amphibians

Conraua, known as slippery frogs or giant frogs is a genus of large frogs from sub-Saharan Africa. Conraua is the only genus in the family Conrauidae. Alternatively, it may be placed in the family Petropedetidae.

Bullfrog is a common English language term to refer to large, aggressive frogs, regardless of species.

<i>Telmatobius macrostomus</i> Species of amphibian

Telmatobius macrostomus, also known as the Lake Junin (giant) frog or Andes smooth frog, is a very large and endangered species of frog in the family Telmatobiidae. This completely aquatic frog is endemic to lakes and associated waters at altitudes of 4,000–4,600 m (13,100–15,100 ft) in the Andes of Junín and Pasco in central Peru. It has been introduced to slow-moving parts of the upper Mantaro River, although it is unclear if this population still persists.

Telmatobius dankoi, also known as the Loa water frog, is a species of critically endangered aquatic frog in the family Telmatobiidae. It is endemic to Chile and is only known from its type locality near Calama, in the El Loa province. Only 14 individuals are known from captivity following the destruction of its habitat prior to 2019, so it may already be extinct in the wild. However, it is doubtfully distinct from Telmatobius halli and thus may not be a distinct species.

<span class="mw-page-title-main">Petropedetidae</span> Family of amphibians

The Petropedetidae are a family of frogs containing three genera and 12 species. They are found in sub-Saharan tropical Africa and are sometimes known under common name African torrent frogs.

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<span class="mw-page-title-main">African bullfrog</span> Species of frog

The African bullfrog, also known as the Giant bullfrog or the South African burrowing frog, is a species of frog in the family Pyxicephalidae. It is also known as the pixie frog due to its scientific name. It is found in Angola, Botswana, Kenya, Malawi, Mozambique, Namibia, South Africa, Tanzania, Uganda, Zambia, Zimbabwe, and possibly the Democratic Republic of the Congo. It has been extirpated from Eswatini. It has long been confused with the edible bullfrog, and species boundaries between them, including exact range limits, are not fully understood. Additionally, P. angusticeps of coastal East Africa only was revalidated as a separate species in 2013.

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<i>Telmatobius culeus</i> Species of amphibian

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<span class="mw-page-title-main">Calyptocephalellidae</span> Family of amphibians

The Calyptocephalellidae are a family of toads found in Chile containing two living genera, Calyptocephalella and Telmatobufo.

<span class="mw-page-title-main">Australobatrachia</span> Clade of frogs

Australobatrachia is a clade of frogs in the suborder Neobatrachia. It comprises three families of frogs with a Gondwanan distribution, being known from Chile, Australia, and New Guinea. Together, they form the sister group to the superfamily Hyloidea.

References

  1. 1 2 3 4 5 6 7 IUCN SSC Amphibian Specialist Group. (2019). "Calyptocephalella gayi". IUCN Red List of Threatened Species . 2019: e.T4055A85633603. doi: 10.2305/IUCN.UK.2019-1.RLTS.T4055A85633603.en . Retrieved 14 June 2023.
  2. ↑ Gómez, R.O.; A.M. Báez; P. Muzzopappa (2011). "A new helmeted frog (Anura: Calyptocephalellidae) from Eocene subtropical lake in northwestern Patagonia, Argentina". Journal of Vertebrate Paleontology. 31 (1): 50–59. doi:10.1080/02724634.2011.539654. hdl: 11336/98850 . S2CID   86761696.
  3. ↑ Mörs, T.; M. Reguero; D. Vasilyan (2020). "First fossil frog from Antarctica: implications for Eocene high latitude climate conditions and Gondwanan cosmopolitanism of Australobatrachia". Scientific Reports. 10 (1): 5051. Bibcode:2020NatSR..10.5051M. doi: 10.1038/s41598-020-61973-5 . PMC   7181706 . PMID   32327670.
  4. 1 2 3 4 AmphibiaWeb: Calyptocephalella gayi. Retrieved 21 March 2015.
  5. ↑ Macle, Adam (January 22, 2017). "10 Largest Frogs and Toads in the World". Gone Froggin. Retrieved 29 May 2021.
  6. 1 2 3 4 5 6 Halliday, T. (2016). The Book of Frogs: A Life-Size Guide to Six Hundred Species from around the World. University Of Chicago Press. p. 89. ISBN   978-0-226-18465-4.
  7. 1 2 3 4 5 Acuña-O., P.L.; C.Ma. Vélez-R.; C.E. Mizobe; C. Bustos-López; M. Contreras-López (2014). "Mortalidad de la poblacíon de rana grande chilena, Calyptocephalella gayi (Calyptocephalellidae), en la laguna Matanzas, del Humedal El Yali, en Chile Central". Anales Museo de Historia Natural de Valparaíso. 27: 35–50.
  8. ↑ Toledo; Suazo; and Viana (2014). Formulated diets for giant Chilean frog Calyptocephalella gayi tadpoles. Cien. Inv. Agr. 41(1): 13-20.
  9. 1 2 3 4 Castañeda, L.E.; P. Sabat; S.P. Gonzalez; R.F. Nespolo (2006). "Digestive Plasticity in Tadpoles of the Chilean Giant Frog (Caudiverbera caudiverbera): Factorial Effects of Diet and Temperature" (PDF). Physiological and Biochemical Zoology. 79 (5): 919–926. doi:10.1086/506006. PMID   16927238. S2CID   20547056. Archived from the original (PDF) on 2020-06-26.
  10. 1 2 Mizobe, C.E.; M. Contreras-López; P.L. Acuña-O.; C.Ma. Vélez-R.; C. Bustos-López (2014). "Mortalidad masiva de la rana grande chilena (Calyptocephalella gayi) en la Reserva Nacional El Yali". Biodiversidata. 2: 30–34.
  11. ↑ "Rana Gigante aparece en Leyda en San Antonio". radiofestival.cl. 28 December 2015. Retrieved 6 January 2020.
  12. ↑ Sabater-Pi, J. (1985). "Contribution to the biology of the Giant Frog (Conraua goliath, Boulenger)". Amphibia-Reptilia. 6 (1): 143–153. doi:10.1163/156853885x00047.
  13. 1 2 3 Veloso M., A. (1977). "Aggressive Behavior and the Generic Relationships of Caudiverbera caudiverbera (Amphibia:Leptodactylidae)". Herpetologica. 33 (4): 434–442.
  14. 1 2 "Expertos advierten que rana chilena está en peligro de desaparecer". Chile Desarrollo Sustentable. 5 August 2014. Retrieved 6 January 2020.
  15. ↑ "Calyptocephalella gayi". CITES. Retrieved 9 January 2020.[ permanent dead link ]
  16. 1 2 Cortes, P.A.; H. Puschel; P. Acuña; J.L. Bartheld; F. Bozinovic (2016). "Thermal ecological physiology of native and invasive frog species: do invaders perform better?". Conserv Physiol. 4 (1): cow056. doi: 10.1093/conphys/cow056 . PMC   5141634 . PMID   27933168.
  17. 1 2 Vidal, M.A.; F. Novoa-Muñoz; E. Werner; C. Torres; R. Nova (2017). "Modeling warming predicts a physiological threshold for the extinction of the living fossil frog Calyptocephalella gayi". J Therm Biol. 69: 110–117. doi:10.1016/j.jtherbio.2017.07.001. PMID   29037370.
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