Bufonids are the true toads, although some are not particularly toadlike. The large genus Bufo has over 200 species and is naturally cosmopolitan except for Australia. The other genera are distributed in three tropical areas: South America, Africa, and southeast Asia. Some of these other genera are clearly derived from Bufo, but others belong to a major evolutionary lineage that is distinct from Bufo and its allies.
Bufonids range in size from 20 to more than 200 mm. No bufonids have teeth, although the absence of teeth occurs sporadically in other frog groups. Also, many bufonids (but not all) have a Bidder's organ, which is a mass of gonadal tissue in males that has the appearance of an immature testis. If the testis of a male is surgically removed, the Bidder's organ will enlarge and differentiate into a functional ovary.
Most toads of the genus Bufo are dull. However, Bufo periglenes is brightly colored and exhibits extreme color dimorphism between males and females. This rare toad lives in the cool wind-swept cloud forests of Costa Rica near Monteverde. It has not been observed in several years and may be extinct.
Species of the genus Atelopus, also called Harlequin Frogs, are brightly colored. Atelopus zeteki from Panama have skin toxins (Brown et al. 1977). Bufo spinulosus is among the highest ranging amphibians; it is known from about 5000 m elevation in the Andes of South America.
Evolution and Systematics
Discussion of Phylogenetic Relationships
- Altiphrynoides malcolmi
- Atelophryniscus chrysophorus
- Bufoides meghalayanus
- Crepidophryne epiotica
- Didynamipus sjostedti
- Frostius pernambucensis
- Mertensophryne micranotis
- Laurentophryne parkeri
- Metaphryniscus sosae
- Parapelophryne scalptus
- Pseudobufo subasper
- Schismaderma carens
- Spinophrynoides osgoodi
Ford and Cannatella (1993) defined Bufonidae as the node-based name for the most recent common ancestor of living bufonids (Bufo, Frostius, etc., as listed in Frost ), and all its descendants. Putative synapomorphies of Bufonidae are the presence of Bidder's organ (Duellman and Trueb, 1986); a unique pattern of insertion of the hyoglossus muscle; absence of the posterior constrictor muscle (Trewavas, 1933); the absence of teeth; origin of depressor mandibulae muscle solely from the squamosal, and associated angle of orientation of the squamosal (Griffiths, 1954; Starrett, 1968); and the presence of the "otic element," an independent ossification in the temporal region that fuses to the otic ramus of the squamosal (Griffiths, 1954).
The distribution of Bidder's organ was summarized by Roessler et al. (1990), and knowledge of the taxonomic distribution is reasonably good. No bufonids are known to have teeth, but teeth are absent in unrelated taxa, including some basal telmatobiine leptodactylids with no clear relationships to other taxa. Barring the close relationship of any of these taxa to Bufonidae, the absence of teeth is tentatively considered a synapomorphy of Bufonidae. The conformation of the hyoglossus muscle and absence of the constrictor posterior muscle were listed by Trewavas (1933) as possible diagnostic features of Bufonidae. These characters are virtually unique in bufonids among frogs, and Cannatella has confirmed the presence of these in several other bufonid genera, but greater taxonomic coverage is needed. Griffiths (1954) stated that the "otic element" is diagnostic of bufonids, but his observations on its development were limited to seven species of Bufo and two species of Atelopus.
Graybeal and Cannatella (1995) discussed the phylogenetic status of all of the bufonid genera.
Molecular Biology and Genetics
Statistics of barcoding coverage
|Specimen Records:||2,715||Public Records:||402|
|Specimens with Sequences:||2,061||Public Species:||42|
|Specimens with Barcodes:||1,727||Public BINs:||69|
|Species With Barcodes:||166|
The true toads are the family Bufonidae, members of the order Anura (frogs and toads). They are the only family of anurans in which all members are known as "toads". The bufonids now comprise more than 35 genera, Bufo being the most widespread and well known.
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.
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 Bufo marinus, are more toxic than others. Some "psychoactive toads", such as the Colorado River toad Bufo alvaris, have been used recreationally for the effects of their bufotoxin.
The Bufonidae family contains about 500 species among 37 genera.
|Genus Latin name and author||Common name||Species|
|Adenomus Cope, 1861||Dwarf toads|
|Altiphrynoides Dubois, 1987||Ethiopian toads|
|Amietophrynus Frost et al., 2006|
|Andinophryne Hoogmoed, 1985||Andes toads|
|Ansonia Stoliczka, 1870||Stream toads|
|Atelopus Duméril & Bibron, 1841||Stubfoot toads|
|Bufo Laurenti, 1768||Toads|
|Bufoides Pillai & Yazdani, 1973||Mawblang toad|
|Capensibufo Grandison, 1980||Cape toads|
|Churamiti Channing & Stanley, 2002|
|Crepidophryne Cope, 1889||Cerro Utyum toads|
|Dendrophryniscus Jiménez de la Espada, 1871||Tree toads|
|Didynamipus Andersson, 1903||Four-digit toad|
|Duttaphrynus Frost et al., 2006|
|Epidalea Cope, 1864||Natterjack toad|
|Frostius Cannatella, 1986||Frost's toads|
|Ingerophrynus Frost et al., 2006|
|Laurentophryne Tihen, 1960||Parker's tree toad|
|Leptophryne Fitzinger, 1843||Indonesia tree toads|
|Melanophryniscus Gallardo, 1961||South American redbelly toads|
|Mertensophryne Tihen, 1960||Snouted frogs|
|Metaphryniscus Señaris, Ayarzagüena & Gorzula, 1994|
|Nectophryne Buchholz & Peters, 1875||African tree toads|
|Nectophrynoides Noble, 1926||African live-bearing toads|
|Nimbaphrynoides Dubois, 1987||Nimba toads|
|Oreophrynella Boulenger, 1895||Bush toads|
|Osornophryne Ruiz-Carranza & Hernández-Camacho, 1976||Plump toads|
|Parapelophryne Fei, Ye & Jiang, 2003|
|Pedostibes Günther, 1876||Asian tree toads|
|Pelophryne Barbour, 1938||Flathead toads|
|Pseudepidalea Frost, et al. 2006|
|Pseudobufo Tschudi, 1838||False toad|
|Rhinella Fitzinger, 1826||Beaked toads|
|Schismaderma Smith, 1849||African split-skin toad|
|Truebella Graybeal & Cannatella, 1995|
|Werneria Poche, 1903||Smalltongue toads|
|Wolterstorffina Mertens, 1939||Wolterstorff toads|
- Zweifel, Richard G. (1998). Cogger, H.G. & Zweifel, R.G., ed. Encyclopedia of Reptiles and Amphibians. San Diego: Academic Press. pp. 91–92. ISBN 0-12-178560-2.
- Brown, Federico D., Eugenia M. Del Pino, and Georg Krohne. "Bidder's organ in the toad Bufo marinus: Effects of orchidectomy on the morphology and expression of lamina-associated polypeptide 2." Development, Growth & Differentiation. Wiley Online Library. Volume 44, Issue 6, pages 527–535, December 2002.
- "Amphibian Species of the World 5.1 - Bufonidae". 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.