There are around 6000 species of frogs and toads that inhabit almost all parts of the world, except the Antarctica. This article provides a brief overview about them.
The smallest known vertebrate in the world is a frog with a body length of around seven millimeters. Named Paedophryne amauensis, this frog was discovered in Papua New Guinea.
From the smallest frog Paedophryne amauensis to the largest Conraua goliath, there are thousands of frog and toad species with varying sizes and features. They belong to the order Anura, which is the most diverse order of amphibians. According to the ITIS (Integrated Taxonomic Information System), there are 47 families in the order Anura, which has around 6000 species. The order is divided into three suborders – Archaeobatrachia,Mesobatrachia and Neobatrachia.
Even though, toads are considered as frogs, there are some differences between them. While most of the frogs have a smooth, thin, and slimy skin; toads are rough and warty. Frogs are mostly found near water sources. Toads have short and stocky hind legs that are meant for hopping, whereas frogs have long, strong hind legs that help them jump. True toads belong to the family Bufonidae, but families, like Bombinatoridae, Alytidae, Pelobatidae, Rhinophrynidae, Scaphiopodidae, Microhylidae etc., have some toad species. Given below is a list of different types of frogs and toads, along with their pictures. This classification is based on their common features.
Midwife Toads and Painted Frogs
The family Alytidae consists of two genera – Alytes and Discoglossus. This family of primitive frogs was earlier known as Discoglossidae, which has another name – Colodactylidae. The members of the genus Alytes are called midwife toads, as the male members carry eggs on their backs. They live on land, and are found in Europe and some parts of Africa. The members of the genus Discoglossus are also found in these regions. This genus has six species, which are known as painted frogs that are mostly found near water bodies. They have pointed snouts and big eyes. Most of the painted frogs have patches on their backs.
Screeching Frogs or Squeakers
As the name rightly suggests, these frogs are known for their calls. Though they produce high-pitched calls, these frogs are small, and have a maximum body length of two inches. Usually found in leaf litter, they belong to the genus Arthroleptis in the subfamily Arthroleptinae. This subfamily has six other genera including Trichobatrachus, which has the unique hairy frog named Trichobatrachus robustus. The subfamily Arthroleptinae belongs to the family Arthroleptidae, which has another subfamily called Leptopelinae. The latter has a single genus Leptopelis. Peacock tree frogs belong to this genus and they are known for their high pitched calls. In fact, this frog produces two different types of sounds. One type is used to prevent other males from entering the territory, whereas the other type is used to attract females.
These toads have bright colored marks on their bellies, and hence, the name. Most of them have black markings with red and yellow patterns. As in many other animal species, these bright colors indicate the toxicity of these aquatic toads. When threatened by predators, they arch their backs and display their bellies, as a warning sign. These toads belong to the genus Bombina and family Bombinatoridae. This family has another genus named Barbourula with two species, which are known as jungle toads. They are seen in Philippines and Borneo Islands, whereas members of the genus Bombina are found throughout Eurasia. Both jungle toads and fire-bellied toads have flattened bodies. The mating calls of these toads resemble dog barking, but the sounds are very low to be heard properly. These toads are kept as exotic pets.
These bright-colored toads belong to the genus Brachycephalus in the family Brachycephalidae. They are small-sized toads with a body length of around one inch. In fact, the smallest frog of the Southern Hemisphere belongs to this family. It is none other than the Izecksohn’s toad Brachycephalus didactylus or the Brazilian gold toad. Found in the Atlantic forest of Brazil, most of the saddleback toads are bright yellow in color. The bright color denotes its toxicity. Unlike most of the other frogs, saddlebacks have three toes and three fingers each on their feet and hands respectively. Recently, another genus was added to this family. This genus, called Ischnocnema, has some frogs from Brazil and Argentina.
Illustration of the Brazilian gold frog (Brachycephalus didactylus) on a fingernail.
It is one of the smallest frogs in the world.
They belong to the family Bufonidae, which has around 45 genera with more than 500 species. Most of the members of this family are typical toads with a dry warty skin. They have parotid glands behind their eyes, and most of them are toothless. The parotid glands secrete toxins, when these toads are threatened. The toxins secreted by Bufo guttatus or smooth-sided toad is lethal enough to cause heart failure in humans (if ingested). Even cane toad is toxic enough to cause human deaths, if consumed. Male members of this family have the Bidder’s organ, a spherical part located near the kidney. This organ turns into an ovary, if the testes stop functioning properly. True toads are found in almost all parts of the world, except Australia and Antarctica.
Glass Frogs/Leaf Frogs
Most of these frogs are arboreal; and are found in various regions, like Mexico, Venezuela, Brazil, Argentina, etc. Many of them are light green, and have translucent skin on their bellies. Some of these frogs have transparent skin on their bellies. In such frogs, the internal organs can be seen, and hence, the name glass frogs. They are small-sized frogs that may resemble tree frogs that belong to the family Hylidae. Tree frogs have eyes that bulge sideways, whereas the eyes of glass frogs face forward. Glass frogs belong to the family Centrolenidae, with two subfamilies – Allophryninae and Centroleninae. While Allophryninae has a single genus Allophryne, with a single species; Centroleninae has four genera.
These small frogs are found in certain parts of South America. There are two species that belong to the genus Rhinoderma. Discovered by Charles Darwin, these frogs have a proboscis-like elongation on the tips of their noses. They are seen in green or brown colors, with dark undersides. Some of them have white blotches on their bellies. The male members have unusually large vocal sacs, which they use for carrying tadpoles. These frogs belong to the Subfamily Cycloramphinae in the family Cycloramphidae, which has another subfamily Alsodinae and genus Rupirana. The family was earlier known as Rhinodermatidae.
Poison Dart Frogs
These frogs produce toxic secretions and are brightly colored to warn predators. They belong to the family Dendrobatidae with three subfamilies – Colostethinae, Dendrobatinae, and Hyloxalinae. Those belonging to the genus Phyllobates in the subfamily Dendrobatinae are found to be highly poisonous. The indigenous people of Americas used blowdarts tipped with the toxic secretions of these frogs, and hence, the name. The golden poison dart frog (Phyllobates terribilis) produces enough venom to kill ten adult humans. The level of toxicity may vary from one species to another. It has been observed that the highly toxic species have only one predator – Leimadophis epinephelus, a snake which is immune to these toxins. Many species of poisonous dart frogs are raised as exotic pets; and the captive ones are found to be less poisonous, as compared to the wild ones.
Found in the mountain streams of South Africa, ghost frogs belong to the family Heleophrynidae, which has two genera – Hadromophryneand Heleophryne. While the genus Hadromophryne has a single species, there are six species in the genus Heleophryne. Most of them have transparent white skin on their bellies. The internal organs can be seen through this skin. This could be a reason for the name of these frogs. These frogs are found in the Skeleton Gorge in the Table Mountain, where the local people brought dead bodies. This is another possible reason for the name, ghost frogs. Their bodies are flattened, so that they can easily accommodate themselves in rock crevices. They have toe discs to help them attach to rocks. Even the tadpoles have sucking mouth parts, with which they cling to rocks.
These frogs are known for their parental care. Females carry eggs on their backs, till they hatch. Sometimes froglets are also seen carried by these frogs. Even the males are actively involved in proper placing of the eggs. Native to South and Central America, these frogs belong to the family Hemiphractidae, which has five genera. They includeCryptobatrachus, Flectonotus, Gastrotheca, Hemiphractus, andStefania. Around 80% of the marsupial frogs belong to the genus Gastrotheca.
There are two species of tailed frogs that belong to the genus Ascaphus. Both the mountain tailed frog (Ascaphus montanus) and the coastal tailed frog (Ascaphus truei) have distinct tails. In fact, the tail is an extension of the male cloaca. With the extended cloaca, internal fertilization is possible, and the chances of sperm loss are less. These frogs inhabit mountain streams, and their tadpoles have suckers to attach themselves to the rocks in streams. They are found in Northwest United States and British Columbia. Though they were earlier classified under the family Ascaphidae, now the genus is placed in the family Leiopelmatidae, along with the genus Leiopelma. Like tailed frogs, the members of this genus have additional vertebrae, but they lack the tail. However, they have remains of tail muscles. This genus has four species that are known as Newzealand primitive frogs.
From the very name, it is evident that these frogs live in leaf litter. In fact, many of them live in forest floors and have excellent camouflaging skills. They look like dead leaves with leaf-like veins, patterns, and color. A species named Megophrys nasuta does not look like frog, as it has projections that extend from the eyes and nose. Hence, the frog is also known as long-nosed horned frog. Litter frogs are found in Southeast Asia, and they belong to the family Megophryidae that has ten genera. They include Borneophrys, Brachytarsophrys, Leptobrachella, Leptobrachium, Leptolalax, Megophrys, Ophryophryne, Oreolalax, Scutiger, and Xenophrys.
European Spadefoot Toads
Four species of the genus Pelobates of the family Pelobatidae are known as European spadefoot toads. They have round bodies and smooth skin. European spadefoots are often found in dull brown mottled skin with stocky bodies and big eyes that bulge out. They have vertical pupils. The name is derived from the sharp, bony protrusions on their hind feet. This structure helps them to dig soil, as they are also known as burrowing toads. They are found in Europe and certain parts of Asia and Africa.
Parsley frogs belong to the genus Pelodytes, in the family Pelodytidae. The name is derived from the green marks on the body of the common parsley frog. Three different species of parsley frogs are found in green and brown colors. The coloring of these frogs does not play a major role in camouflaging, as seen in litter frogs. These slender flogs have slightly flattened bodies and small warts. The large eyes have vertical pupils. They are mostly found in Southwest Europe.
These frogs belong to the family Pipidae, which has five genera –Hymenochirus, Pipa, Pseudhymenochirus, Silurana, and Xenopus. The members of this family are toothless and tongueless. These aquatic frogs have flattened bodies, webbed feet, and claws on the hind feet. They lack ears, but have special adaptations that enable them to hear sounds when they are under water. The lateral lines that run through the sides of their bodies help them sense sounds and movements under water. These primitive frogs do not have vocal cords, but they produce sounds with the bony rods in the larynx. Those belonging to the genus Pipa is found in the tropical regions of South America, whereas those in the other genera are found in Africa.
Mexican Burrowing Toads
These round, fat toads (Rhinophrynus dorsalis) spend most of the time in their burrows. Their characteristic feature is the reddish-orange or yellowish line that runs through the dorsal sides of their bodies. These toads have sharp claws on their feet, and these appendages help them in burrowing soil. Unlike other frogs that have their tongues attached to the tip of the mouth, these burrowing toads have their tongues attached to the back of their mouth. Their calls are very loud and distinct. They inflate themselves while calling or when they are alarmed. The inflated body looks like a slightly flattened balloon with a pointed nose. So they are also called nose toads. They are found in regions like, Texas, Honduras, Mexico, and Costa Rica. These toads comprise the only species of the genus Rhinophrynus, which is the lone genus in the family Rhinophrynidae.
American Spadefoot Toads
Found in Canada, United States, and Mexico, these toads are burrowing in nature. They have a spade-like appendage on their hind feet, and this helps them in digging. They are stocky, and have bulging eyes with vertical pupils. They are mostly found in arid regions, and spend most of their time in their burrows. These toads belong to the family Scaphiopodidae, which has two genera – Scaphiopus and Spea. The genus Scaphiopus has southern spadefoot toads with three species, and the genus Spea has four species that are known as western spadefoot toads.
These frogs have prominent noses, and hence, the name. While most of the burrowing frogs dig rear-first, shovelnose frogs burrow head-first. They have a smooth skin, round bodies, and short and stocky legs. Eggs are laid in underground burrows. Once they hatch, the female either makes a tunnel to the water source or carry the tadpoles to the water. There are nine species of shovelnose frogs that belong to the single genus Hemisus in the family Hemisotidae. These frogs are found in savannahs, marshes, grasslands, and swamps of Africa.
These frogs belong to the family Hylidae with three subfamilies –Hylinae, Pelodryadina, and Phyllomedusinae. Many of them live on trees and tall vegetation. Being small-sized, they can easily move on slender branches and twigs. They have bulging eyes with binocular vision, and adhesive toe pads that help them to climb and move on tree branches. However, some members of this family are terrestrial or semi-aquatic. Tree frogs are found in shades of green, white, gray, yellow, and brown. The body color and pattern helps them in camouflaging. They are mostly found in forests, woodlands, and marshes. These smooth skinned frogs can be found in varying sizes. Their body length ranges between 3 to 14 centimeters. They are carnivorous and feed on insects, worms, and even small frogs. The most popular among them are green tree frogs, which are raised as pets. Another common tree frog is gray tree frog or North American tree frog, which come out during spring for mating. The color of their warty skin may vary between green and gray, according to the background. Found in most parts of the United States, the northern cricket frog (Acris crepitans) is a tree frog that does not inhabit trees. They are very small and grow up to 1.5 inches in length. The dorsal skin of northern cricket frogs carry blotchy patterns and a color that ranges between gray, green, or brown. Their mating call resembles the sounds produced by crickets and hence, the name.
African Reed Frogs and Running Frogs
Otherwise known as hyperolids, these frogs have a brightly-patterned skin. They have a body length that ranges between 1. 5 to 10 centimeters. They belong to the family Hyperoliidae, which has 17 genera. There are around 100 species of reed frogs that belong to some of these genera, especially, Hyperolius. Reed frogs are very popular as pets. Usually, male argus reed frogs are green and females are reddish-brown with colorful marks. While most of the members of this family are found in Africa, those belonging to the genus Heterixalus are found in Madagascar only. Those in the genus Tachycnemis are only seen in the Seychelles Islands. While some inhabit trees, some are completely terrestrial. There are around 30 species in the genus Afrixalus, and they are called banana frogs. They make nests by folding leaves that grow above water bodies. Members of the genus Kassina are known as running frogs, due to their distinctive walking pattern, using their hind legs. More than half of the species of this family belong to the genus Hyperolius.
Southern or Tropical Frogs
These frogs belong to the family Leptodactylidae, which has four genera. They include Hydrolaetare, Leptodactylus, Paratelmatobius,and Scythrophrys. White-lipped frogs belong to the genusLeptodactylus, and the name is derived from their white upper lip. They are also known as ditch frogs, as they are found in marshes, ditches, and muddy areas. This genus makes up a major part of the family Leptodactylidae. Most of the frogs in this family make foam nests in which eggs are laid. Such nests can be seen on the ground, surface of water bodies, or cracks and crevices. Tadpoles live in these nests, till they metamorphize. Most of them come in shades of gray, green, and brown. Some species like the gold striped frog, have bright lines and spots that are used for tricking predators, because bright colors indicate toxicity. The size and features of leptodactylids vary drastically. Another notable species in the family is the Surinam horned frog Ceratophrys cornuta, which has an unusually wide mouth and horns above the eyes.
These frogs belong to the family Mantellidae, which has three subfamilies – Boophinae, Laliostominae, and Mantellinae. This family has numerous species that have little similarities between them. While some are arboreal or aquatic, most of them are terrestrial. These frogs are found in Madagascar and Mayotte Island. The subfamily Boophinae has a single genus named Boophis. The members of this genus resemble tree frogs. Some of them have transparent bellies, like glass frogs, and are called skeleton frogs. While Laliostominae has two genera and four species, Mantellinae forms a major part of the family. This subfamily has two genera – Mantella and Mantidactylus. Those in the genus Mantellaare like poison dart frogs. These small-sized frogs are brightly colored and they produce toxins too.
These frogs have wide bodies and narrow mouths, and they belong to the family Microhylidae. The family has numerous species that are classified under 11 subfamilies (Cophylinae, Dyscophinae, Gastrophryninae, Hoplophryninae, Kalophryninae, Melanobatrachinae, Microhylinae, Otophryninae, Phrynomerinae, and Scaphiophryninae). Apart from these subfamilies, this family has 12 other genera. All microhylids are not narrowmouthed. Some of them have normal body proportions. For example, those belonging to the subfamilies Brevicipitidae, Gastrophryninae, and Microhylinae are narrowmouthed. While most of these frogs are found in New Guinea and Madagascar, they can be seen in some parts of Central and South America, Asia, and Australia. Their body length ranges from 1.5 to 10 centimeters. There are three species of tomato frogs that belong to the genus, which is the sole genus in the subfamily Dyscophinae. Tomato frogs are natives to Madagascar.
True frogs belong to the family Ranidae, and are found in almost all parts of the world, except Antarctica. While most of them are aquatic, some are arboreal, and others are terrestrial. You may also find some amphibians and burrowers in this family. These frogs have a smooth and moist skin, webbed feet, narrow waists, and long and strong legs. Some of them are live-bearers. This family has the following genera – Amolops, Babina, Clinotarsus, Glandirana, Huia, Humerana, Hylarana, Lithobates, Meristogenys, Odorrana, Pelophylax, Pseudorana, Pterorana, Rana, Sanguirana, and Staurois.
The wood frog is a common Ranidae species, which has a mask-like marking over the eyes. It is said that the wood frog tadpoles can identify their siblings. The American bullfrog (Rana catesbeiana) can be found across North America. They are found in large numbers and are voracious eaters. Like the American bullfrogs, the African ones are also very large and are commonly found in many African countries. Their habitat includes freshwater lakes, pastures, canals, ditches, dry savanna, and moist savanna. In some countries, these bull frogs are grown as pets. The northern leopard frog (Lithobates pipiens) are common in the United States. They are fairly large and are often found near water bodies with dense aquatic plants. The dorsal part of their bodies are green to brown with large round spots. These dark spots are bordered with light-colored rings. Their mating calls are like snores. Northern leopard frogs are used for research purposes.
Moss Frogs and Gliding Frogs
These frogs belong to the family Rhacophoridae, which has two subfamilies – Buergeriinae and Rhacophorinae. While the subfamily Buergeriinae has a single genus with a few species, the subfamily Rhacophorinae has 11 genera with numerous species. Most of these frogs in this family are arboreal, and they lay eggs in tree holes filled with water, or branches that are located above water sources. Some of them make foam nests on tree branches. Flying of gliding frogs belong to this family and they have specialized webbing in their fingers and toes. This feature enables them to glide in air. Some types of moss frogs, like Theloderma corticale are also found in this family. These frogs have a mottled and warty skin, and are seen in mossy habitats.
These frogs belong to the family Sooglossidae, which has two genera –Sechellophryne and Sooglossus. They have two species each. In other words, this family has only four species. Sooglossus gardineri or Gardiner’s frog is one of the smallest frogs in the world, and has a maximum length of 11 millimeters. Though this frog lacks middle ear cavity, it has the ability to hear. These frogs are golden brown with a dark line that extends from their mouths to legs. Seychelles frogs are often seen hiding in rock crevices or within fallen leaves on the ground.
African Torrent Frogs
Found in some parts of Africa, these frogs belong to the family Petropedetidae, which has two genera – Petropedetes and Conraua. While the genus Petropedetes has ten species, there are six species in Conraua. The largest frog in the world, named goliath frog, belongs to the genus Conraua. It can grow to a length of up to 33 inches and have a body weight of more than three kilograms. These giant frogs are mainly found in Cameroon and Equatorial Guinea.
You may come across different types of classification of amphibians, but none of them are conclusive. This article follows the Integrated Taxonomic Information System (ITIS). The above said are some of the common types of frogs and toads, classified on the basis of their features. Apart from those discussed above, there are some more families that are given below.
- Family Aromabatidae – Subfamilies Allobatinae, Anomaloglossinae, Aromobatinae.
- Family Calyptocephalellidae – Genera Calyptocephalella, Telmatobufo
- Family Ceratobatrachidae – Genera Batrachylodes, Ceratobatrachus, Discodeles, Palmatorappia, Platymantis
- Family Ceratophryidae – Subfamilies Batrachylinae, Ceratophryinae, Telmatobiinae
- Family Craugastoridae – Genera Craugastor, Haddadus
- Family Dicroglossidae – Subfamilies Dicroglossinae, Occidozyginae
- Family Eleutherodactylidae – Subfamilies Eleutherodactylinae, Phyzelaphryninae
- Family Hylodidae – Genera Crossodactylus, Hylodes, Megaelosia
- Family Leiuperidae – Genera Edalorhina, Engystomops, Eupemphix, Pleurodema, Pseudopaludicola, Somuncuria
- Family Limnodynastidae – Genera Adelotus, Heleioporus, Lechriodus, Limnodynastes, Neobatrachus, Notaden, Philoria, Platyplectrum
- Family Micrixalidae – Genus Micrixalus
- Family Nasikabatrachidae – Genus Nasikabatrachus
- Family Nyctibatrachidae – Genera Lankanectes, Nyctibatrachus
- Family Phrynobatrachidae – Genus Phrynobatrachus
- Family Ptychadenidae – Genera Hildebrandtia, Lanzarana, Ptychadena
- Family Pyxicephalidae – Subfamilies Cacosterninae, Pyxicephalinae
- Family Ranixalidae – Genus Indirana
- Family Rhacophoridae – Subfamilies Buergeriinae, Rhacophorinae
- Family Strabomantidae – Subfamilies Holoadeninae, Strabomantinae.
As mentioned above, there are around 6000 species of frogs and toads with varying features. While some are less than ten millimeters, some are more than 33 inches in length. Some are brightly colored, some others are dull. You may find some unique and beautiful members, whereas weird ones are also not uncommon.