Mexican Burrowing Toad
Encyclopedia
The Mexican Burrowing Toad (Rhinophrynus dorsalis) is the only species in the genus Rhinophrynus and the family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

 Rhinophrynidae of order
Order (biology)
In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...

 Anura
Frog
Frogs are amphibians in the order Anura , formerly referred to as Salientia . Most frogs are characterized by a short body, webbed digits , protruding eyes and the absence of a tail...

. These frogs live from the southern Texas
Texas
Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...

 through Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...

, Guatemala
Guatemala
Guatemala is a country in Central America bordered by Mexico to the north and west, the Pacific Ocean to the southwest, Belize to the northeast, the Caribbean to the east, and Honduras and El Salvador to the southeast...

, Honduras
Honduras
Honduras is a republic in Central America. It was previously known as Spanish Honduras to differentiate it from British Honduras, which became the modern-day state of Belize...

, El Salvador
El Salvador
El Salvador or simply Salvador is the smallest and the most densely populated country in Central America. The country's capital city and largest city is San Salvador; Santa Ana and San Miguel are also important cultural and commercial centers in the country and in all of Central America...

 to Nicaragua
Nicaragua
Nicaragua is the largest country in the Central American American isthmus, bordered by Honduras to the north and Costa Rica to the south. The country is situated between 11 and 14 degrees north of the Equator in the Northern Hemisphere, which places it entirely within the tropics. The Pacific Ocean...

 and Costa Rica
Costa Rica
Costa Rica , officially the Republic of Costa Rica is a multilingual, multiethnic and multicultural country in Central America, bordered by Nicaragua to the north, Panama to the southeast, the Pacific Ocean to the west and the Caribbean Sea to the east....

. The family was once more widespread, including species ranging as far north as Canada, but these died out in the Oligocene
Oligocene
The Oligocene is a geologic epoch of the Paleogene Period and extends from about 34 million to 23 million years before the present . As with other older geologic periods, the rock beds that define the period are well identified but the exact dates of the start and end of the period are slightly...

.

Physical description

The Mexican Burrowing Toad grows to 8 cm (3.1 in) in length, and usually has red spots on its bloated body with a red stripe along the center of its back. It has short legs, and a small, pointed head. Its feet have horny, shovel-like appendages which, along with the short, powerful legs, aid it in digging. Its eyes are relatively small, and the tympanum
Tympanum (zoology)
The tympanum is an external hearing structure in animals such as frogs, toads, insects, and mammals, to name a few.-Anurans:In frogs and toads, it is located just behind the eye. It does not actually process sound waves; it simply transmits them to the amphibian's inner ear, which is protected...

 is not visible. Unique among the frogs, the Mexican Burrowing Toad's tongue is projected directly out the front of the mouth, instead of being flipped out, as in all other frogs.

Ecology and behavior

As the name suggests, the Mexican Burrowing Toad is a burrowing animal (fossorial
Fossorial
A fossorial organism is one that is adapted to digging and life underground such as the badger, the naked mole rat, and the mole salamanders Ambystomatidae...

), and it spends a large part of its life underground. After a large period of rain, it will emerge from the soil and lay eggs in a water source. They will travel up to 1.6 km (0.994196378639691 mi) to find a suitable water source. Due to the unpredictability of rain, the frog will call and mate during any time of the year. It will burrow into soft soil with its short legs once the environment has dried up. The egg and tadpole
Tadpole
A tadpole or polliwog is the wholly aquatic larval stage in the life cycle of an amphibian, particularly that of a frog or toad.- Appellation :...

 stages of the life cycle are relatively short. The eggs take only a few days to hatch, and the tadpoles develop over one to three months.

The call is a loud, low pitched "wh-o-o-o-a". When it is calling or alarmed, the body becomes inflated. The Mexican Burrowing Toad eats insects, primarily ant
Ant
Ants are social insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants evolved from wasp-like ancestors in the mid-Cretaceous period between 110 and 130 million years ago and diversified after the rise of flowering plants. More than...

s and termite
Termite
Termites are a group of eusocial insects that, until recently, were classified at the taxonomic rank of order Isoptera , but are now accepted as the epifamily Termitoidae, of the cockroach order Blattodea...

s.

Evolutionary independence

The Mexican Burrowing Toad is genetically unique in a number of ways. According to EDGE
Edge
- Aviation :* Leading edge, a line connecting the forward-most points of a wing's profile* Trailing edge, the rear edge of the wing* Zivko Edge 540, an aerobatic aircraft- Mathematics, science and technology :...

, Mexican Burrowing toads are:
"The only species, within the only genus of the family Rhinophrynidae, and with over 190 million years of independent evolution, the Mexican burrowing toad is the most evolutionarily distinct amphibian species on Earth today; a fruit bat, polar bear, killer whale, kangaroo and human are all more similar to one another than this species is to any other amphibian."
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