The Chaco tortoise (''Chelonoidis chilensis''), also known commonly as the Argentine tortoise, the Patagonian tortoise, or the southern wood tortoise, is a

species In biology, a species is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of ...

tortoise Tortoises () are reptiles of the family Testudinidae of the order Testudines (Latin: ''tortoise''). Like other turtles, tortoises have a shell to protect from predation and other threats. The shell in tortoises is generally hard, and like ot ...

in the

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Testudinidae. The species is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found els ...

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the souther ...

Geographic range

The Chaco tortoise is mainly found in

Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, t ...

, but also in

Bolivia , image_flag = Bandera de Bolivia (Estado).svg , flag_alt = Horizontal tricolor (red, yellow, and green from top to bottom) with the coat of arms of Bolivia in the center , flag_alt2 = 7 × 7 square p ...

and

Paraguay Paraguay (; ), officially the Republic of Paraguay ( es, República del Paraguay, links=no; gn, Tavakuairetã Paraguái, links=si), is a landlocked country in South America. It is bordered by Argentina to the south and southwest, Brazil to th ...

, mainly within the Chaco and Monte ecoregions. Its distribution is mainly limited by temperature-related variables, and precipitation in the reproductive period.

Taxonomy

The scientific name for this species, ''Chelonoidis chilensis'', is misleading because it is not native to

Chile Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the eas ...

. It occurs mainly in Argentina, Bolivia and neighboring Paraguay. When the species was first described by

Gray Grey (more common in British English) or gray (more common in American English) is an intermediate color between black and white. It is a neutral or achromatic color, meaning literally that it is "without color", because it can be composed ...

in 1870, he mistakenly thought that Mendoza was in Chile instead of Argentina ( the city was transfer in 1776), thus the misnomer. Sclater corrected Gray's mistake in the same year. However, the rules of

nomenclature Nomenclature (, ) is a system of names or terms, or the rules for forming these terms in a particular field of arts or sciences. The principles of naming vary from the relatively informal conventions of everyday speech to the internationally agre ...

give precedence to the name ''chilensis'', even though it was based on an erroneous assumption, and the name has persisted.

Description

The

carapace A carapace is a dorsal (upper) section of the exoskeleton or shell in a number of animal groups, including arthropods, such as crustaceans and arachnids, as well as vertebrates, such as turtles and tortoises. In turtles and tortoises, the und ...

of ''C. chilensis'' can measure up to 43.3 cm (but usually less than 25 cm) in a straight line, and may be either totally yellowish brown or have dark-brown to black rings surrounding a tan center on each

scute A scute or scutum (Latin: ''scutum''; plural: ''scuta'' "shield") is a bony external plate or scale overlaid with horn, as on the shell of a turtle, the skin of crocodilians, and the feet of birds. The term is also used to describe the anterior po ...

. Specimens found farther south tend to be much larger than those found in farther north populations. The rim of the shell is slightly serrated and has a dark wedge of pigment at the back edge of each scute. The plastron may be uniformly yellowish-brown or have a dark triangular wedge along the seams of each scute. The head, limbs and tail are greyish to yellowish-brown, with the front of each forelimb covered with large, angular scales and each thigh featuring several enlarged

tubercles In anatomy, a tubercle (literally 'small tuber', Latin for 'lump') is any round nodule, small eminence, or warty outgrowth found on external or internal organs of a plant or an animal. In plants A tubercle is generally a wart-like projection, ...

Diet

Like all tortoise species, the Chaco tortoise is primarily herbivorous, consuming grasses, shrubs, fruits, and cactus pads.

Species status

There is only one recognized species. However, some researchers believe ''C. chilensis'' should be divided into three species: ''C. chilensis'', ''C. petersi'', and ''C. donosobarrosi''. Some support ''C. donosobarrosi'' as a subspecies (''C. chilensis donosobarrosi''). There is research to indicate that it may qualify as a separate species, while ''C. petersi'' may just be a variant of ''C. chilensis'', the variances being clinal variations in adjacent populations. However, these taxa mentioned have all been formally synonymised and accepted. The morphological variation is explainable as a factor of elevation. Historically, these have been viewed as separate taxa, with little work done to confirm or deny it. Subsequent molecular analysis has found little to no genetic variation.

Etymology

The specific name (or

subspecific name In zoological nomenclature, a subspecific name is the third part of a trinomen. In zoology there is only one rank below that of species, namely " subspecies". In botanical nomenclature, there are several levels of subspecific names, such as ''v ...

), ''donosobarrosi'', is in honor of Chilean herpetologist

Roberto Donoso-Barros Roberto Donoso-Barros (October 5, 1921 – August 2, 1975) was a Chilean botanist, naturalist, and herpetologist. Early life and education Donoso-Barros was born in Santiago, Chile. He attended the University of Chile in Santiago, earning hi ...

, Beolens, Bo; Watkins, Michael; Grayson, Michael (2011). ''The Eponym Dictionary of Reptiles''. Baltimore: Johns Hopkins University Press. xiii + 296 pp. . (''Geochelone donosobarrosi'', p. 74). and ''petersi'' is in honor of American herpetologist James A. Peters.

References

;Bibliography * * Boulenger GA (1889). ''Catalogue of the Chelonians, Rhynchocephalians, and Crocodiles in the British Museum (Natural History). New Edition.'' London: Trustees of the British Museum (Natural History). (Taylor and Francis, printers). x + 311 pp. + Plates I-III. ("''Testudo argentina''", p. 159). * Gray JE (1870). "Notice of a new Chilian icTortoise (''Testudo chilensis'')". ''Ann. Mag. Nat. Hist., Fourth Series'' 6: 190. ''Testudo (Gopher) chilensis''", new species {{Taxonbar, from1=Q5066111, from2=Q1074424 Chelonoidis Reptiles of Argentina Reptiles of Bolivia Reptiles of Paraguay Reptiles described in 1870 Taxa named by John Edward Gray