The red-footed tortoise (Chelonoidis carbonarius) is a species of tortoise from northern South America. These medium-sized tortoises generally average 30 cm (12 in) as adults, but can reach over 40 cm (16 in). They have dark-colored (nearly black), “loaf”-shaped carapaces (top shell) with a lighter patch in the middle of each scute (shell segment), and a somewhat lighter-colored plastron (underbelly). They also have dark limbs dotted with brightly-colored scales, from which they get their name, that range from pale yellow to vivid or dark red. Visible differences are noted between red-footed tortoises from varying eco-regions. They are closely related to the more easterly-distributed yellow-footed tortoise (C. denticulatus) of the Amazon Basin. Their natural habitat ranges from savannah to forest edges around the Amazon Basin. They are omnivorous tortoises, consuming a wide assortment of plants, grasses, flowers, fruit and (notably) fungi, as well as the occasional earthworm or other invertebrate. When presented with the opportunity, many tortoises will also scavenge on carrion. They do not brumate, due to their equatorial home range, but may aestivate in the hotter, drier months. Red-footed (and yellow-footed) tortoises are popularly kept as pets. Over-collection of eggs, and the capturing of mature animals, from their native habitat has caused them to be listed as “vulnerable” to extinction, despite the relative ease of captive breeding and the availability of captive-bred tortoises. Additionally, many remote tribal groups living in South America still consider the tortoises a basic source of meat, and many are unaware of the species’ overall plight; many travelers and activists report seeing live red-footed tortoises for sale in markets where bushmeat and live animals are sold. Eggs, hatchlings, and even mature tortoises are food for many animal predators, including caimans, crocodiles and giant otters (if near water), as well as birds of prey, bushdogs, jaguars, jaguarundis, margays, certain monkeys, ocelots, pumas and tayras. Population density ranges from locally common to very scarce due, in-part, to habitat destruction and the aforementioned over-collection for food and the pet trade. The species name has often been misspelled as carbonaria, an error introduced in the 1980s when Chelonoidis was elevated to genus and mistakenly treated as feminine, an error recognized and fixed in 2017.
Names Red-footed tortoises have many common names: red-leg, red-legged, or red-foot tortoise (often without the hyphen) and the savanna tortoise, as well as local names, such as carumbe or karumbe, which means 'slow moving' (Brazil, Paraguay), wayapopi or morrocoy (Venezuela, Colombia), and variations of jabuti such as japuta and jabuti-piranga (Brazil, Argentina). In Portuguese, jabuti (jaboti) refers to both the red-footed tortoise and the yellow-footed tortoise. It is also called kati in Natú and sambó in Kiriri.
Taxonomy Red footed tortoises were originally assigned to the genus Testudo (named by Carl Linnaeus in 1758) for a short time, but it soon became the term for turtles with high-domed shells, elephantine legs, and completely terrestrial habits—the tortoises. In 1835, Leopold Fitzinger used Geochelone to differentiate some non-Mediterranean tortoises, apparently based on size and lack of specific identifying characteristics such as the hinged shell in the African hingeback tortoises. He used the term Chelonoidis as a subgenus for the species from South America. Few people used these terms until they were resurrected by Hewitt in 1933 and Loveridge and Williams in 1957. In 1982, Roger Bour and Charles Crumly each separated Geochelone into different genera based on anatomic differences, especially in the skulls. That resulted in the formation or restoration of several genera: Aldabrachelys, Astrochelys, Cylindraspis, Indotestudo, Manouria, and Chelonoidis. Chelonoidis was distinguished from other Geochelone by their South American location, as well as the absence of the nuchal scute (the marginal centered over the neck) and the presence of a large, undivided supracaudal (the scute or scutes directly over the tail), as well as differences in the skull. Many of these generic names are still debated; for example, no specific definition of Geochelone is given, and Chelonoidis is primarily used for geography rather than unique anatomic characteristics. The species name carbonarius means 'coal-like' referring to a dark coal with glowing patches. It was originally identified by Johann Baptist von Spix in 1824. The holotype was kept in the Zoologischen Sammlung des Bayerischen Staates in Munich, Germany, but was lost. Paulo Vanzolini believes it may have come from near the city of Manaus, Brazil, on the Rio Negro. No subspecies of red-footed tortoise are recognized, although many believe the species has five or more variants that may be subspecies or even separate species.
Description Red-footed tortoises show sex, regional, and individual variations in color, shell shape, and minor anatomical characteristics. Adult carapaces are generally an elongated oval with sides that are nearly parallel, although the sides of males may curve inwards. They are fairly highly domed and smooth with a rather flat back (although the scutes may be raised or 'pyramided' in some individuals, especially captive specimens). Often, a high point over the hips is seen, with a small sloped section over the neck. The vertebral and costal scutes (the scutes along the center and sides of the carapace) are black or dark brown with a pale yellow areole in the center. The marginals (scutes along the edge of the carapace) 'tuck under' along the sides and flare slightly over the limbs. They are dark with the pale aureole along the middle of the lower edge. The nuchal scute (the marginal over the neck) is absent, and the marginals over the tail are joined as one large supracaudal. Growth rings are clearly evident in most individuals, but become worn smooth with age.
The plastron (bottom shell) is large and thick along the edges. The gulars (frontmost pair of plastron scutes) do not protrude much past the front of the carapace. The plastron of a male is deeply indented, and the anal scutes (rearmost pair of plastron scutes) may be used to sex the animal while the color pattern varies by region.
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