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Holdridge's toad

March 10, 2023

Holdridge's toad (Incilius holdridgei), formerly Bufo holdridgei, is a species of toad endemic to Costa Rica.[2] In October 2008, it was declared extinct by the International Union for Conservation of Nature in its Red List since the species had not been seen since 1987, despite years of extensive searches. However, the species was rediscovered in 2010 by a Costa Rican herpetologist[3] and is now classified as critically endangered.[1] It is believed that the species is most threatened by the presence of the chytrid fungus in its habitat.[4]

Holdridge's toad
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Amphibia
Order: Anura
Family: Bufonidae
Genus: Incilius
Species:
I. holdridgei
Binomial name
Incilius holdridgei
(Taylor, 1952)
Synonyms

Bufo holdridgei Taylor, 1952
Cranopsis holdridgei (Taylor, 1952)

Description

Taxonomy

Originally found on Barva Volcano in Cordillera Central, Costa Rica, the Holdridge's toad is still endemic to that particular small area of Costa Rica's rainforests. It is named after the research scientist Holdridge for its discovery. It can be distinguished in classification from other toads by its morphological differences. For example, Incilius holdridgei differs from Incilius fastidiosus because of the different cranial crests and from Incilius peripetates due to the different sizes at the adult age.[5]

Morphology

The adult male is between 32 and 46 mm snout vent length (SVL). The adult female is slightly larger, measuring between 38 and 53 mm SVL. Both the male and female have similar dorsum coloration ranging from black to light brown with a lighter colored venter. The limbs, as well as the dorsal and lateral surfaces are spotted with reddish warts of varying sizes. The head is broad with low crests, excluding the thicker supratympanic crest. The reddish colored parotoid gland is smooth and globular. Limbs are shortened and feature fleshy hands and feet that are moderately webbed and lack tubercles. Both males and females of the species lack structures of the ear, causing deafness. Males lack vocal slits and sac, and have unusually hypertrophied testes.[6]

Incilius holdridgei tadpoles are small in size with ovoid-shaped bodies that are dark brown in color and feature a lighter venter surface. The tail and caudal fins are rounded. The mouth is directed ventrally and the oral disc has beaks and 2 to 3 rows of denticles which are bordered by a row of large papillae.[4][6]

Behavior

Incilius holdridgei are fossorial, and remain relatively inactive while burrowed underground. During seasons of heavy rain, they can be found underneath layers of forest floor debris. During dryer periods, they can be found near stream banks. Members of the species become more active during the daytime when they are above ground [6] or crepuscular time. Due to their morphology, Incilius holdridgei are deaf and mute; they apparently do not communicate through sound or have mating calls- a rarity among frogs and toads. Before 1986, the species had been relatively easy to spot during its two-month mating season from April to May when males and females became more active and gathered in the hundreds. However, outside of the mating season, the toads were very difficult to locate.[7] Since 1987, the species has declined in numbers and currently exists in a critically endangered state.[1] Since it was re-discovered in 2010, just few individuals have seen again, for that reason this species is one of the most threatened in the world.

Habitat

Holdridge's toads have been mainly observed in the rainforests of the Central Mountain Range of Costa Rica.[7] The species has recently been found living in open grassy areas.[1] The Holdridge's Toad is a species that exists in montane rainforest of Costa Rica. This class of toads settles below the surfaces’ rubbish inside the forest during the duration of excessive rainfall. They are classified as a fossorial species due to the act of digging or burrowing themselves. When they are not avoiding the heavy rainfall, they favor massy stream banks.[6] The forest, wetlands, and/or pasturelands are sufficient enough for the Holdridge's Toad.[1]

Diet

Due to the fact that the Holdridge's toad is reappearing from assumed extinction, research is beginning on this small organism. Revival of past research gives current research scientists direction of what to discover and learn from this toad. From collected past and new research along, as the Holdridge's is exposed to Costa Rica's rainforests’ bacteria and fungus, the diet can be inferred. The Holdridge's toads' diet includes a broad range of arthropod invertebrates, among them spiders, larval stages of moths and butterflies (lepidopterans), flies, beetles, earwigs (dermoptera), ants, and mites (Savage 2002).[4]

Reproduction

The average age for sexual maturity of Incilius holdridgei is probably about two years. Due to the lack of development of vocal slits and tympana Incilius holdridgei do not have a breeding call. This species is an explosive breeder that lays clutches of large eggs in pools of water on the forest floor, they are also known to lay eggs in man-made drainage ditches.[4] Historically however, Incilius holdridgei were known to breed in more open areas such as pastures, but due to habitat conservation efforts these pastures are now evolving back into forests.[1] The males are known to arrive to these breeding pools following periods of heavy rain around early to mid-April and wait for the arrival of the females. At one time there were so many of them that some of the toads would try to mate with other species during these mating frenzies.[4][7] It is also believed that the females only stay at the breeding pool for about only an hour or so.[4]

In reference to the reproduction of the Holdridge's toad, it was expressed as an “explosive breeder”[8] It acquired this title because it produced eggs in forest floor pools.[9] This species is known to reproduce in big collections in pools in open pastures.[1]

History

Until 2009 the toad had not been observed since 1986. Due to the toad not being observed for over twenty years, the International Union for Conservation of Nature declared the species extinct.[7] Between 1968 and 2009 there were no sightings of Holdridge's toad in their natural environment. Extensive searches were led to determine if the species was extinct. The searches lasted for seven years before the toad was declared extinct.[1] Multiple causes are believed to have led to the toad's presumed extinction, including chytridiomycosis, climate change, and deforestation.[5] The main threat to Holdridge's toad is thought to be chytridiomycosis, a fungal pathogen, Batrachochytrium dendrobatidis, that causes an infections disease in amphibians. The fungus keratinizes any keratin-containing skin layers in both the tadpoles and adult frogs.[10] High levels of this fungus were detected in the breeding grounds of Holdridge's toad before and after the species appeared to vanish.[5] In 2009, tadpole and adult toads were discovered in two separate ponds that reclassified the species as critically endangered.[1]

From 2008 to 2010, there was extensive searching efforts for the species. The search suggested that the adult population is less than 50 mature individuals, leading to its listing as Critically Endangered.[11] Juveniles were found, indicating relatively recent reproductive activity, but no large aggregations were seen; this species should be considered Critically Endangered.[12] The entire known range of Incilius holdridgei falls within a protected area: Parque Nacional Braulio Carrillo. However, breeding ponds in Alto El Roble are near the main road and may be under threat from increasing tourism.[13]

Conservation efforts

The toad was added to the Red List of Endangered Species in 2006.[7] Of the forty recorded visits, Holdridge's toad has been observed on twenty-two occasions, accounting for sixty-seven organisms.[14] Much of the known range of this species is protected in Parque Nacional Braulio Carrillo, 20 km north-east of the capital of San José. The two sites where the species is known to persist in 2010 are located in the Cerro Dantos and Jaguarundi Refuges, neither of which has the same protection status as a national park. Even with the lower protection status, the forest cover of these refuges remains intact and seemingly not threatened. Although one might think that the population of Incilius holdridgei is recovering, information on the only known populations is still very limited; there needs to be more research on the population dynamics, environmental factors of the breeding sites, population health and genetics.[1]

A monitoring project is being carried out under the auspices of the Foundation Mohamed Bin Zayed Species Conservation Fund.[15]

It is believed that the major cause of the toad's decrease in population is chytridiomycosis, an infectious disease that affects amphibians caused by the chytrid fungus. The increase of the chytrid fungus has been connected to global warming.[1]

References

  1. ^ a b c d e f g h i j k NatureServe.; IUCN SSC Amphibian Specialist Group (2020). "Incilius holdridgei". IUCN Red List of Threatened Species. 2020: e.T54664A54358615. doi:10.2305/IUCN.UK.2020-3.RLTS.T54664A54358615.en. Retrieved 18 November 2021.
  2. ^ Frost, Darrel R. (2015). "Incilius holdridgei (Taylor, 1952)". Amphibian Species of the World: an Online Reference. Version 6.0. American Museum of Natural History. Retrieved 5 November 2015.
  3. ^ "Reconsidering Extinction: Rediscovery of Incilius holdridgei (Anura: Bufonidae) in Costa Rica After 25 Years". ResearchGate. Retrieved 27 December 2015.
  4. ^ a b c d e f Incilius holdridgei. AmphibiaWeb (4 October 2011). Retrieved on 2013-01-01.
  5. ^ a b c Incilius holdridgei . Retrieved 2014-10-23
  6. ^ a b c d Holdridge's Toad. Encyclopedia of Life. Retrieved on 2014-10-19.
  7. ^ a b c d e Costa Rica's Holdridge Toad Declared Extinct. ECO PRESERVATION SOCIETY (16 October 2008). Retrieved on 2014-10-15. (with image visible)
  8. ^ Humans, pets and fungi the latest species killers. Retrieved 2014-10-23
  9. ^ . Retrieved 2014-10-23
  10. ^ An Overview of Chytridiomycosis. Retrieved 2014-10-23
  11. ^ NatureServe & IUCN SSC Amphibian Specialist Group, 2012. Incilius holdridgei. The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 24 October 2014
  12. ^ "Conservation Status and Ecological Notes of the Previously Extinct Toad Incilius holdridgei (Taylor, 1952), Costa Rica". ResearchGate. Retrieved 27 December 2015.
  13. ^ Life History, Abundance, Activity, and Special Behaviors[1]. Retrieved 2014-10-23
  14. ^ . Retrieved on 2014-10-15
  15. ^ "Holdridge's Toad Conservation Case Study | The Mohamed bin Zayed Species Conservation Fund". www.speciesconservation.org. Retrieved 27 December 2015.

Further reading

  • Frost, D. R.; Grant, T.; Faivovich, J. N.; Bain, R. H.; Haas, A.; Haddad, C. L. F. B.; De Sá, R. O.; Channing, A.; Wilkinson, M.; Donnellan, S. C.; Raxworthy, C. J.; Campbell, J. A.; Blotto, B. L.; Moler, P.; Drewes, R. C.; Nussbaum, R. A.; Lynch, J. D.; Green, D. M.; Wheeler, W. C. (2006). "The Amphibian Tree of Life". Bulletin of the American Museum of Natural History. 297: 1–291. doi:10.1206/0003-0090(2006)297[0001:TATOL]2.0.CO;2. hdl:2246/5781. S2CID 86140137.
  • Pauly, G. B., D. M. Hillis, and D. C, Cannatella. (2004) The history of a Nearctic colonization: Molecular phylogenetics and biogeography of the Nearctic toads (Bufo). Evolution 58: 2517–2535.  
  • Abarca, J.; G. Chaves, A. García-Rodríguez and R. Vargas. 2010. Reconsidering extinction: Rediscovery of Incilius holdridgei (Anura, Bufonidae) in Costa Rica After 25 years. Herpetological review. 41(2): 150–152.
  • Abarca, J. 2012. Conservation Status and Ecological Notes of the Previously Extinct Toad Incilius holdridgei (Taylor, 1952), Costa Rica. Froglog 20(3): 10–12.

External links

 
Wikispecies has information related to Incilius holdridgei.

March 10, 2023
holdridge, toad, this, article, require, cleanup, meet, wikipedia, quality, standards, specific, problem, much, repetition, loose, please, help, improve, this, article, november, 2015, learn, when, remove, this, template, message, incilius, holdridgei, formerl. This article may require cleanup to meet Wikipedia s quality standards The specific problem is Too much repetition loose Please help improve this article if you can November 2015 Learn how and when to remove this template message Holdridge s toad Incilius holdridgei formerly Bufo holdridgei is a species of toad endemic to Costa Rica 2 In October 2008 it was declared extinct by the International Union for Conservation of Nature in its Red List since the species had not been seen since 1987 despite years of extensive searches However the species was rediscovered in 2010 by a Costa Rican herpetologist 3 and is now classified as critically endangered 1 It is believed that the species is most threatened by the presence of the chytrid fungus in its habitat 4 Holdridge s toadConservation statusCritically Endangered IUCN 3 1 1 Scientific classificationKingdom AnimaliaPhylum ChordataClass AmphibiaOrder AnuraFamily BufonidaeGenus InciliusSpecies I holdridgeiBinomial nameIncilius holdridgei Taylor 1952 SynonymsBufo holdridgei Taylor 1952Cranopsis holdridgei Taylor 1952 Contents 1 Description 1 1 Taxonomy 1 2 Morphology 1 3 Behavior 1 4 Habitat 1 5 Diet 1 6 Reproduction 2 History 2 1 Conservation efforts 3 References 4 Further reading 5 External linksDescription EditTaxonomy Edit Originally found on Barva Volcano in Cordillera Central Costa Rica the Holdridge s toad is still endemic to that particular small area of Costa Rica s rainforests It is named after the research scientist Holdridge for its discovery It can be distinguished in classification from other toads by its morphological differences For example Incilius holdridgei differs from Incilius fastidiosus because of the different cranial crests and from Incilius peripetates due to the different sizes at the adult age 5 Morphology Edit The adult male is between 32 and 46 mm snout vent length SVL The adult female is slightly larger measuring between 38 and 53 mm SVL Both the male and female have similar dorsum coloration ranging from black to light brown with a lighter colored venter The limbs as well as the dorsal and lateral surfaces are spotted with reddish warts of varying sizes The head is broad with low crests excluding the thicker supratympanic crest The reddish colored parotoid gland is smooth and globular Limbs are shortened and feature fleshy hands and feet that are moderately webbed and lack tubercles Both males and females of the species lack structures of the ear causing deafness Males lack vocal slits and sac and have unusually hypertrophied testes 6 Incilius holdridgei tadpoles are small in size with ovoid shaped bodies that are dark brown in color and feature a lighter venter surface The tail and caudal fins are rounded The mouth is directed ventrally and the oral disc has beaks and 2 to 3 rows of denticles which are bordered by a row of large papillae 4 6 Behavior Edit Incilius holdridgei are fossorial and remain relatively inactive while burrowed underground During seasons of heavy rain they can be found underneath layers of forest floor debris During dryer periods they can be found near stream banks Members of the species become more active during the daytime when they are above ground 6 or crepuscular time Due to their morphology Incilius holdridgei are deaf and mute they apparently do not communicate through sound or have mating calls a rarity among frogs and toads Before 1986 the species had been relatively easy to spot during its two month mating season from April to May when males and females became more active and gathered in the hundreds However outside of the mating season the toads were very difficult to locate 7 Since 1987 the species has declined in numbers and currently exists in a critically endangered state 1 Since it was re discovered in 2010 just few individuals have seen again for that reason this species is one of the most threatened in the world Habitat Edit Holdridge s toads have been mainly observed in the rainforests of the Central Mountain Range of Costa Rica 7 The species has recently been found living in open grassy areas 1 The Holdridge s Toad is a species that exists in montane rainforest of Costa Rica This class of toads settles below the surfaces rubbish inside the forest during the duration of excessive rainfall They are classified as a fossorial species due to the act of digging or burrowing themselves When they are not avoiding the heavy rainfall they favor massy stream banks 6 The forest wetlands and or pasturelands are sufficient enough for the Holdridge s Toad 1 Diet Edit Due to the fact that the Holdridge s toad is reappearing from assumed extinction research is beginning on this small organism Revival of past research gives current research scientists direction of what to discover and learn from this toad From collected past and new research along as the Holdridge s is exposed to Costa Rica s rainforests bacteria and fungus the diet can be inferred The Holdridge s toads diet includes a broad range of arthropod invertebrates among them spiders larval stages of moths and butterflies lepidopterans flies beetles earwigs dermoptera ants and mites Savage 2002 4 Reproduction Edit The average age for sexual maturity of Incilius holdridgei is probably about two years Due to the lack of development of vocal slits and tympana Incilius holdridgei do not have a breeding call This species is an explosive breeder that lays clutches of large eggs in pools of water on the forest floor they are also known to lay eggs in man made drainage ditches 4 Historically however Incilius holdridgei were known to breed in more open areas such as pastures but due to habitat conservation efforts these pastures are now evolving back into forests 1 The males are known to arrive to these breeding pools following periods of heavy rain around early to mid April and wait for the arrival of the females At one time there were so many of them that some of the toads would try to mate with other species during these mating frenzies 4 7 It is also believed that the females only stay at the breeding pool for about only an hour or so 4 In reference to the reproduction of the Holdridge s toad it was expressed as an explosive breeder 8 It acquired this title because it produced eggs in forest floor pools 9 This species is known to reproduce in big collections in pools in open pastures 1 History EditUntil 2009 the toad had not been observed since 1986 Due to the toad not being observed for over twenty years the International Union for Conservation of Nature declared the species extinct 7 Between 1968 and 2009 there were no sightings of Holdridge s toad in their natural environment Extensive searches were led to determine if the species was extinct The searches lasted for seven years before the toad was declared extinct 1 Multiple causes are believed to have led to the toad s presumed extinction including chytridiomycosis climate change and deforestation 5 The main threat to Holdridge s toad is thought to be chytridiomycosis a fungal pathogen Batrachochytrium dendrobatidis that causes an infections disease in amphibians The fungus keratinizes any keratin containing skin layers in both the tadpoles and adult frogs 10 High levels of this fungus were detected in the breeding grounds of Holdridge s toad before and after the species appeared to vanish 5 In 2009 tadpole and adult toads were discovered in two separate ponds that reclassified the species as critically endangered 1 From 2008 to 2010 there was extensive searching efforts for the species The search suggested that the adult population is less than 50 mature individuals leading to its listing as Critically Endangered 11 Juveniles were found indicating relatively recent reproductive activity but no large aggregations were seen this species should be considered Critically Endangered 12 The entire known range of Incilius holdridgei falls within a protected area Parque Nacional Braulio Carrillo However breeding ponds in Alto El Roble are near the main road and may be under threat from increasing tourism 13 Conservation efforts Edit The toad was added to the Red List of Endangered Species in 2006 7 Of the forty recorded visits Holdridge s toad has been observed on twenty two occasions accounting for sixty seven organisms 14 Much of the known range of this species is protected in Parque Nacional Braulio Carrillo 20 km north east of the capital of San Jose The two sites where the species is known to persist in 2010 are located in the Cerro Dantos and Jaguarundi Refuges neither of which has the same protection status as a national park Even with the lower protection status the forest cover of these refuges remains intact and seemingly not threatened Although one might think that the population of Incilius holdridgei is recovering information on the only known populations is still very limited there needs to be more research on the population dynamics environmental factors of the breeding sites population health and genetics 1 A monitoring project is being carried out under the auspices of the Foundation Mohamed Bin Zayed Species Conservation Fund 15 It is believed that the major cause of the toad s decrease in population is chytridiomycosis an infectious disease that affects amphibians caused by the chytrid fungus The increase of the chytrid fungus has been connected to global warming 1 References Edit a b c d e f g h i j k NatureServe IUCN SSC Amphibian Specialist Group 2020 Incilius holdridgei IUCN Red List of Threatened Species 2020 e T54664A54358615 doi 10 2305 IUCN UK 2020 3 RLTS T54664A54358615 en Retrieved 18 November 2021 Frost Darrel R 2015 Incilius holdridgei Taylor 1952 Amphibian Species of the World an Online Reference Version 6 0 American Museum of Natural History Retrieved 5 November 2015 Reconsidering Extinction Rediscovery of Incilius holdridgei Anura Bufonidae in Costa Rica After 25 Years ResearchGate Retrieved 27 December 2015 a b c d e f Incilius holdridgei AmphibiaWeb 4 October 2011 Retrieved on 2013 01 01 a b c Incilius holdridgei Retrieved 2014 10 23 a b c d Holdridge s Toad Encyclopedia of Life Retrieved on 2014 10 19 a b c d e Costa Rica s Holdridge Toad Declared Extinct ECO PRESERVATION SOCIETY 16 October 2008 Retrieved on 2014 10 15 Archived with image visible Humans pets and fungi the latest species killers Retrieved 2014 10 23 Humans pets and fungi the latest species killers Retrieved 2014 10 23 An Overview of Chytridiomycosis Retrieved 2014 10 23 NatureServe amp IUCN SSC Amphibian Specialist Group 2012 Incilius holdridgei The IUCN Red List of Threatened Species Version 2014 2 lt www iucnredlist org gt Downloaded on 24 October 2014 Conservation Status and Ecological Notes of the Previously Extinct Toad Incilius holdridgei Taylor 1952 Costa Rica ResearchGate Retrieved 27 December 2015 Life History Abundance Activity and Special Behaviors 1 Retrieved 2014 10 23 FrogLog Panama Amphibian Rescue and Conservation Project Retrieved on 2014 10 15 Holdridge s Toad Conservation Case Study The Mohamed bin Zayed Species Conservation Fund www speciesconservation org Retrieved 27 December 2015 Further reading EditFrost D R Grant T Faivovich J N Bain R H Haas A Haddad C L F B De Sa R O Channing A Wilkinson M Donnellan S C Raxworthy C J Campbell J A Blotto B L Moler P Drewes R C Nussbaum R A Lynch J D Green D M Wheeler W C 2006 The Amphibian Tree of Life Bulletin of the American Museum of Natural History 297 1 291 doi 10 1206 0003 0090 2006 297 0001 TATOL 2 0 CO 2 hdl 2246 5781 S2CID 86140137 Pauly G B D M Hillis and D C Cannatella 2004 The history of a Nearctic colonization Molecular phylogenetics and biogeography of the Nearctic toads Bufo Evolution 58 2517 2535 Abarca J G Chaves A Garcia Rodriguez and R Vargas 2010 Reconsidering extinction Rediscovery of Incilius holdridgei Anura Bufonidae in Costa Rica After 25 years Herpetological review 41 2 150 152 Abarca J 2012 Conservation Status and Ecological Notes of the Previously Extinct Toad Incilius holdridgei Taylor 1952 Costa Rica Froglog 20 3 10 12 External links Edit Wikispecies has information related to Incilius holdridgei Photo at The Guardian Retrieved from https en wikipedia org w index php title Holdridge 27s toad amp oldid 1139124241, wikipedia, wiki, book, books, library,

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