True toad

Summary

A true toad is any member of the family Bufonidae, in the order Anura (frogs and toads). This is the only family of anurans in which all members are known as toads, although some may be called frogs (such as harlequin frogs). The bufonids now comprise more than 35 genera, Bufo being the best known.

True toads
Temporal range: Late Paleocene – Recent[1]57–0 Ma
Common toad or European toad, Bufo bufo
Territorial call of an Atelopus franciscus male
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Amphibia
Order: Anura
Superfamily: Hyloidea
Family: Bufonidae
Gray, 1825
Genera
Over 35 see text
Native distribution of Bufonidae (in black)
Song of Common toad or European toad, Bufo bufo.
Common toad, female and male on her back.

History edit

 
American toad (Anaxyrus americanus)

Bufonidae is thought to have originated in South America. Some studies date the origin of the group to after the breakup of Gondwana, about 78–98 million years ago in the Late Cretaceous.[2] In contrast, other studies have dated the origin of the group to the early Paleocene.[3] The bufonids likely radiated out of South America during the Eocene, with the entire radiation occurring during the Eocene to Oligocene, marking an extremely rapid divergence likely facilitated by the Paleogene's changing climatic conditions.[3]

Taxonomy edit

The following phylogeny of most genera in the family is based on Portik and Papenfuss, 2015:,[4] Chan et al., 2016,[5] Chandramouli et al., 2016,[6] and Kok et al., 2017[3]

Melanophryniscus

Ingerophrynus alongside Leptophryne was grouped as basal to the clade containing all other Southeast Asian toad genera and Ghatophryne by Portik and Papenfuss, but was found to group with Phrynoidis and Rentapia by Chan et al. Ghatophryne was grouped with Phrynoidis and Rentapia by Portik and Papenfuss but was found to group with Pelophryne and Ansonia by Chan et al. In addition, Sabahphrynus was grouped with Strauchbufo and Bufo by Portik and Papenfuss but was found to group with Pelophryne, Ansonia, and Ghatophryne by Chan et al.

Characteristics edit

True toads are widespread and are native to every continent except Australia and Antarctica, inhabiting a variety of environments, from arid areas to rainforest. Most lay eggs in paired strings that hatch into tadpoles, although, in the genus Nectophrynoides, the eggs hatch directly into miniature toads.[1]

All true toads are toothless and generally warty in appearance. They have a pair of parotoid glands on the back of their heads. These glands contain an alkaloid poison which the toads excrete when stressed. The poison in the glands contains a number of toxins causing different effects. Bufotoxin is a general term. Different animals contain significantly different substances and proportions of substances. Some, like the cane toad Rhinella marina, are more toxic than others. Some "psychoactive toads", such as the Colorado River toad Incilius alvarius,[7] have been used recreationally for the effects of their bufotoxin.

Depending on the species, male or female toads may possess a Bidder's organ, a trait unique to all bufonids except genera Melanophryniscus and Truebella.[8] Under the right conditions, the organ becomes an active ovary.[9]

The loss of teeth has arisen in frogs independently over 20 times. Notably, all members of Bufonidae are toothless. Another Anuran family with a comparable degree of edentulism is the family Microhylidae.[10]

Reproduction edit

Internal fertilization occurs in four bufonid genera.[11]

Ascaphus (all species) and Eleutherodactylus (two species, E. coqui and E. jasperi) are the only other frog genera that have internal fertilization.[11] Limnonectes larvaepartus also has internal fertilization.[12]

Taxonomy and genera edit

The family Bufonidae contains over 570 species among 52 genera.

Genus name and author Common name Species
Adenomus Cope, 1861 Dwarf toads
2
Altiphrynoides Dubois, 1987 Ethiopian toads
2
Amazophrynella Fouquet et al., 2012
12
Anaxyrus Tschudi, 1845
23
Ansonia Stoliczka, 1870 Stream toads
34
Atelopus Duméril & Bibron, 1841 Stubfoot toads
96
Barbarophryne Beukema, de Pous, Donaire-Barroso, Bogaerts, Garcia-Porta, Escoriza, Arribas, El Mouden, and Carranza, 2013 (1 sp.) Tiznit toad; Brongersma's toad
1
Blythophryne Chandramouli et al., 2016[13] Andaman bush toads
1
Bufo Garsault, 1764 Toads
18
Bufoides Pillai & Yazdani, 1973 Mawblang toads; Rock toads
2
Bufotes Rafinesque, 1815 Palearctic green toads
15
Capensibufo Grandison, 1980 Cape toads
5
Churamiti Channing & Stanley, 2002
1
Dendrophryniscus Jiménez de la Espada, 1871 Tree toads
16
Didynamipus Andersson, 1903 Four-digit toad
1
Duttaphrynus Frost et al., 2006 Dutta's toads
23
Epidalea Cope, 1864 Natterjack toad
1
Firouzophrynus Safaei-Mahroo and Ghaffari, 2020 Firouz's toads
5
Frostius Cannatella, 1986 Frost's toads
2
Ghatophryne Biju, Van Bocxlaer, Giri, Loader, and Bossuyt, 2009
2
Incilius Cope, 1863 Central American toads; Middle American toads; Cerro Utyum toads
39
Ingerophrynus Frost, Grant, Faivovich, Bain, Haas, Haddad, de Sá, Channing, Wilkinson, Donnellan, Raxworthy, Campbell, Blotto, Moler, Drewes, Nussbaum, Lynch, Green, and Wheeler, 2006 Hainan toads
12
Laurentophryne Tihen, 1960 Parker's tree toad
1
Leptophryne Fitzinger, 1843 Indonesia tree toads
3
Melanophryniscus Gallardo, 1961 South American redbelly toads
29
Mertensophryne Tihen, 1960 Snouted frogs
14
Metaphryniscus Señaris, Ayarzagüena & Gorzula, 1994
1
Nannophryne Günther, 1870
4
Nectophryne Buchholz & Peters, 1875 African tree toads
2
Nectophrynoides Buchholz & Peters, 1875 African live-bearing toads
13
Nimbaphrynoides Dubois, 1987 Nimba toads
1
Oreophrynella Boulenger, 1895 Bush toads
8
Osornophryne Ruiz-Carranza & Hernández-Camacho, 1976 Plump toads
11
Parapelophryne Fei, Ye & Jiang, 2003
1
Pedostibes Günther, 1876 Asian tree toads
1
Pelophryne Barbour, 1938 Flathead toads
13
Peltophryne Fitzinger, 1843 Caribbean toads
14
Phrynoidis Fitzinger in Treitschke, 1842 Rough toads
2
Poyntonophrynus Frost, Grant, Faivovich, Bain, Haas, Haddad, de Sá, Channing, Wilkinson, Donnellan, Raxworthy, Campbell, Blotto, Moler, Drewes, Nussbaum, Lynch, Green, and Wheeler, 2006 Pygmy toads
11
Pseudobufo Tschudi, 1838 False toad
1
Rentapia Chan, Grismer, Zachariah, Brown, and Abraham, 2016
2
Rhaebo Cope, 1862 Cope toads
13
Rhinella Fitzinger, 1826 Beaked toads
94
Sabahphrynus Matsui, Yambun, and Sudin, 2007 Sabah earless toad
1
Schismaderma Smith, 1849 African split-skin toad
1
Sclerophrys Tschudi, 1838
44
Sigalegalephrynus Smart, Sarker, Arifin, Harvey, Sidik, Hamidy, Kurniawan, and Smith, 2017 Puppet toads
5
Strauchbufo Fei, Ye, and Jiang, 2012 Siberian toad; Mongolian toad
1
Truebella Graybeal & Cannatella, 1995
2
Vandijkophrynus Frost, Grant, Faivovich, Bain, Haas, Haddad, de Sá, Channing, Wilkinson, Donnellan, Raxworthy, Campbell, Blotto, Moler, Drewes, Nussbaum, Lynch, Green, and Wheeler, 2006 Van Dijk's toads
6
Werneria Poche, 1903 Smalltongue toads
6
Wolterstorffina Mertens, 1939 Wolterstorff toads
3
Xanthophryne Biju, Van Bocxlaer, Giri, Loader & Bossuyt, 2009
2

The family also contains an incertae sedis species, "Bufo" scorteccii Balletto & Cherchi, 1970.

References edit

  1. ^ a b Zweifel, Richard G. (1998). Cogger, H.G.; Zweifel, R.G. (eds.). Encyclopedia of Reptiles and Amphibians. San Diego: Academic Press. pp. 91–92. ISBN 978-0-12-178560-4.
  2. ^ Pramuk, Jennifer B.; Robertson, Tasia; Sites, Jack W.; Noonan, Brice P. (2008). "Around the world in 10 million years: biogeography of the nearly cosmopolitan true toads (Anura: Bufonidae)". Global Ecology and Biogeography. 17 (1): 72–83. doi:10.1111/j.1466-8238.2007.00348.x. ISSN 1466-8238.
  3. ^ a b c Kok, Philippe J. R.; Ratz, Sebastian; MacCulloch, Ross D.; Lathrop, Amy; Dezfoulian, Raheleh; Aubret, Fabien; Means, D. Bruce (2018). "Historical biogeography of the palaeoendemic toad genus Oreophrynella (Amphibia: Bufonidae) sheds a new light on the origin of the Pantepui endemic terrestrial biota". Journal of Biogeography. 45 (1): 26–36. doi:10.1111/jbi.13093. ISSN 1365-2699. S2CID 90886846.
  4. ^ Portik, Daniel M.; Papenfuss, Theodore J. (2015-08-06). "Historical biogeography resolves the origins of endemic Arabian toad lineages (Anura: Bufonidae): Evidence for ancient vicariance and dispersal events with the Horn of Africa and South Asia". BMC Evolutionary Biology. 15 (1): 152. doi:10.1186/s12862-015-0417-y. ISSN 1471-2148. PMC 4527211. PMID 26245197.
  5. ^ Chan, Kin Onn; Grismer, L. Lee; Zachariah, Anil; Brown, Rafe M.; Abraham, Robin Kurian (2016-01-20). "Polyphyly of Asian Tree Toads, Genus Pedostibes Günther, 1876 (Anura: Bufonidae), and the Description of a New Genus from Southeast Asia". PLOS ONE. 11 (1): e0145903. Bibcode:2016PLoSO..1145903C. doi:10.1371/journal.pone.0145903. ISSN 1932-6203. PMC 4720419. PMID 26788854.
  6. ^ Chandramouli, S. R.; Vasudevan, Karthikeyan; Harikrishnan, S.; Dutta, Sushil Kumar; Janani, S. Jegath; Sharma, Richa; Das, Indraneil; Aggarwal, Ramesh (2016-01-20). "A new genus and species of arboreal toad with phytotelmonous larvae, from the Andaman Islands, India (Lissamphibia, Anura, Bufonidae)". ZooKeys (555): 57–90. Bibcode:2016ZooK..555...57C. doi:10.3897/zookeys.555.6522. ISSN 1313-2970. PMC 4740822. PMID 26877687.
  7. ^ "The IUCN Red List of Threatened Species". IUCN Red List of Threatened Species. Retrieved 2019-01-19.
  8. ^ Piprek, Rafal P., et al. “Bidder's Organ – Structure, Development and Function.” The International Journal of Developmental Biology, vol. 58, no. 10-11–12, 2014, pp. 819–27. Crossref, doi:10.1387/ijdb.140147rp.
  9. ^ Brown, Federico D.; Del Pino, Eugenia M.; Krohne, Georg (December 2002). "Bidder's organ in the toad Bufo marinus: Effects of orchidectomy on the morphology and expression of lamina-associated polypeptide 2". Development, Growth & Differentiation. 44 (6): 527–535. doi:10.1046/j.1440-169X.2002.00665.x. ISSN 1440-169X. PMID 12492511. S2CID 44753338.
  10. ^ Paluh, Daniel J., et al. “Rampant Tooth Loss Across 200 Million Years of Frog Evolution.” BioRxiv, 2021. Crossref, doi:10.1101/2021.02.04.429809.
  11. ^ a b Vitt, Laurie J.; Caldwell, Janalee P. (2014). Herpetology: An Introductory Biology of Amphibians and Reptiles (4th ed.). Academic Press. p. 122.
  12. ^ Iskandar, D. T.; Evans, B. J.; McGuire, J. A. (2014). "A novel reproductive mode in frogs: a new species of fanged frog with internal fertilization and birth of tadpoles". PLOS ONE. 9 (12): e115884. Bibcode:2014PLoSO...9k5884I. doi:10.1371/journal.pone.0115884. PMC 4281041. PMID 25551466.
  13. ^ S. R. Chandramouli, Karthikeyan, Vasudevan, S Harikrishnan, Sushil Kumar Dutta, S Jegath Janani, Richa Sharma, Indraneil Das, Ramesh Aggarwal. “A new genus and species of arboreal toad with phytotelmonous larvae, from the Andaman Islands, India (Lissamphibia, Anura, Bufonidae)” ZooKeys (2016) 555: 57-90, https://doi.org/10.3897/zookeys.555.6522
  • "Amphibian Species of the World 5.1 - Bufonidae". Archived from the original on 2012-07-15. Retrieved 2008-04-10.
  • Stebbins, Robert. Western Reptiles & Amphibians (3rd ed.). Houghton Mifflin Co., 2003.
  • Halliday, Tim R., and Kraig Adler (editors). The New Encyclopedia of Reptiles & Amphibians. Facts on File, New York, 2002.

External links edit