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ZOOLOGY

The whereabouts of the small black tapir

A new and as-yet controversial species is more widely distributed in the Amazon than previously thought

Not quite in grasslands or in forests: the small black tapir is found in transitional areas between open vegetation and denser forests

Illustrations Sandro CastelliNot quite in grasslands or in forests: the small black tapir is found in transitional areas between open vegetation and denser forestsIllustrations Sandro Castelli

A new species of tapir living in the Amazon Region—the anta-pretinha, or small black tapir, as described in the December 2013 issue of the Journal of Mammalogy—has been hailed by many as the most extraordinary zoological discovery of this century. Indeed, it appears to be the first tapir species identified since 1865, and the largest animal discovered by scientists since 1992, when researchers described the saola, a bovine that lives in the forests of Vietnam and Cambodia.

The paper was the culmination of a 10-year effort on the part of a team headed by Mario Cozzuol, a paleontologist at the Federal University of Minas Gerais (UFMG). This month, he and his colleagues will reveal new data on the ecology and genetics of the small black tapir—which they have described and given the scientific name Tapirus kabomani—at the International Tapir Symposium of the International Union for Conservation of Nature (IUCN), to be held in Campo Grande, in the Brazilian state of Mato Grosso do Sul. The data will include photos, videos and unprecedented measurements of small black tapirs living in the states of Pará and Roraima and in Bolivia, suggesting that the animal is distributed across nearly the entire Brazilian Amazon and in neighboring countries.

This evidence also confirms that, unlike Tapirus terrestris, the best-known South American tapir, which chooses to live in either dense forests or open grasslands, T. kabomani prefers a more varied landscape that features a mosaic of both open and densely-vegetated areas. “All the places where we have found the species are like that,” Cozzuol says. “It could be coincidental, but T. kabomani may even behave differently from T. terrestris.”

Not all mammal experts are convinced that the small black tapir is a separate species. Some researchers believe they are likely just specimens of T. terrestris that are slightly shorter and darker than average. During the IUCN event, Cozzuol will participate in a roundtable on the validity of the new species. The discussion may seem to center around a byzantine taxonomic issue, but in fact it will attempt to answer a practical question: Is it worthwhile to include T. kabomani on the IUCN Red List of Threatened Species and, in an effort to protect it, to adopt measures other than those currently in use to preserve T. terrestris?

Although the new species is not at high risk of extinction, its savory meat, enormous size (it is the largest animal native to South America) and long gestation period make the Brazilian tapir highly vulnerable to overhunting and loss of habitat. The species is in serious danger of disappearing in several parts of the country in the next few decades, as has already occurred in the Northeast and much of the South and Southeast. Local extinction of the animal could affect the entire biodiversity of a region because, as a voracious herbivore, it helps disperse seeds in grasslands and forests.

The debate will in fact provide a live forum for continuing a discussion that began in writing, first in a closed group for researchers on Facebook, and subsequently in articles that appeared in the August 2014 issue of the Journal of Mammalogy. A group of researchers headed by Robert Voss, a zoologist at the American Museum of Natural History (AMNH), revisited some of the analyses carried out by Cozzuol’s team and maintains that the species is nonexistent.

“Have several generations of neotropical mammalogists really failed to recognize a species widely distributed in Amazonia?” Voss and his colleagues ask in their paper. “Yes, I’m afraid they failed,” replies Cozzuol, who refuted the criticism in that same issue of the journal. “It has happened before and it will happen again; it’s not a sin.”

Odd skull
The search for confirmation of the small black tapir’s existence began by chance in 2002 when Cozzuol, then a professor at the Federal University of Rondônia (UFIR), arranged for his undergraduate intern, Elizete Holanda—now a paleontologist at the Federal University of Roraima—to study a 45,000-year-old fossil skull, found in the Madeira River, that belonged to an extinct tapir species. While comparing the fossil with the skulls of other extinct and living species, Holanda discovered another skull in UFIR’s collection. It had odd dimensions that did not correspond to expectations for any known species.

The skull, collected in a fishing village north of Porto Velho, had a bullet hole and other marks made by hunters. Holanda’s father, who had been a rubber tapper, commented on another type of tapir he knew of, a small black one, that he used to hunt because its meat was tastier than that of the common tapir. “That was when we began to notice that everyone in the area was saying there were two kinds of tapir,” Cozzuol says.

“Most biologists who were working with mammals from the region knew about this, but they didn’t believe the people,” the paleontologist recalls. The main reason why the researchers ignored people’s observations was that tapir specimens of the same species exhibit a wide variety of colors and sizes. Furthermore, the researchers thought it unlikely that two very similar species would occupy the same habitat, because competition for food and space would bring one of them to extinction. “But since I’m a paleontologist and I know there are fossil records of different tapir species living simultaneously in the same region of the Americas, I’m not driven by that assumption,” Cozzuol comments.

Some confirmation was needed as to what is happening in nature today, but Cozzuol did not obtain a permit to capture a live specimen of the probable new species and compare it with the skull that Holanda had found. Only later did he obtain the resources to conduct expeditions in the Amazon, in collaboration with a team headed by geneticist Fabrício Santos and ecologist Flávio Rodrigues, both from UFMG. On these trips, the researchers met with local hunters to get their advice in the event they were to kill a small black tapir. In doing so, the researchers would be able to collect bones, hides and DNA samples of the meat. On their first encounter, a hunter led them to a carcass of one of the animals that had been killed a few weeks earlier. “The skull had the features we were expecting,” Cozzuol says.

Their suspicion was also confirmed during visits to Karitiana Indian villages in the state of Rondônia, where tribesmen stack the skulls obtained in their hunts as trophies. “There were two stacks for the tapirs, one of which had the dimensions expected for the small black tapir,” recalls Cozzuol, who named the species Arabo kabomani, in honor of the name given to it by the Paumari Indians.

The researchers knew, however, that they would need a lot more evidence to convince their colleagues that the hypothesis of a new species merited serious consideration. “A biological species is a group of populations that have an evolutionary history separate from other populations; it is not something that can be observed directly,” Cozzuol explains. “The hypothesis must be tested through integrated genetic, morphological and other types of analyses.”

To confirm the existence of the new species, the researchers compared skull measurements of small black tapirs with those of the skulls of four other living species and a number of tapir fossils. They also compared three gene sequences from the mitochondrial DNA of four small black tapirs with the same genes from dozens of tapirs of all species, obtained from the GenBank open database. “Most studies of tapirs use only one mitochondrial gene,” Cozzuol explains. In both the shape of its skull and its DNA, the small black tapir appeared to be different from the other species.

The study’s conclusion was a review of the natural history of tapirs. They are considered living fossils because they have changed little since they emerged 50 million years ago, having survived the extinction of the large animal fauna that inhabited the Americas until 10,000 years ago. Besides the new T. kabomani, there are only four species living today: the Asian tapir (T. indicus), in Malaysia; the Central American or Baird’s tapir (T. bairdii); the mountain tapir (T. pinchaque), which lives in the Andean habitats of Peru, Ecuador and Colombia; and the Brazilian tapir (T. terrestris), found in nearly every tropical biome of South America. The ancestors of T. kabomani likely separated from those of the Brazilian and mountain tapirs at least 300,000 years ago.

One need not be an Amazonian hunter to distinguish T. kabomani from T. terrestris with the naked eye. The small black tapir is much smaller and shorter, with shorter legs than T. terrestris. It has darker hair, a lower mane and a broader forehead. The males of all tapir species tend to be a little smaller than the females, and this size difference between the sexes is more pronounced among the small black tapirs. Another difference between the sexes is a white patch on the head that extends from the cheeks to the neck—which is an exclusive marking of the females. “Some T. terrestris individuals have patches on the cheeks, but they are indistinct, and can appear in both sexes,” Cozzuol explains.

Enough evidence?
Not at all convinced by the evidence of a new species, Voss and his colleagues dispute all of these conclusions. They re-examined the same genetic data using an alternate statistical method and concluded that the differences between the DNA sequences are too small to consider the small black tapir as a separate species.

Cozzuol explains that his team redid the analysis using the same technique as Voss, the details of which he was able to obtain only after the paper was published, and that therefore his reply does not appear in the same issue of the journal. His results were different, and they still confirm the existence of T. kabomani. “I still didn’t understand how they arrived at those findings,” Cozzuol says. He also objects that they criticized his skull measurement data without replicating them. “The AMNH has a much larger collection of T. terrestris than we do,” he says. “It would take less than a week to take the data and confirm our analysis.”

“I remain convinced that it is not a valid species,” Voss says. “The genetic evidence is inadequate.” He believes that the hypothesis should also be tested using DNA from the cell nuclei, in addition to the mitochondrial DNA already analyzed. Cozzuol and Santos are analyzing precisely that at present, but they have already concluded that it is not possible to distinguish any species of South American tapir by nuclear DNA genes normally used as markers in this type of study, which means they will need to look for differences in less-widely known nuclear DNA sequences. “His arguments are unsupported, and they go beyond reasonable requirements,” Cozzuol says. “I have no doubt that we could have done better, but other species have been described recently with much less detail and data.”

“The ethnographic evidence also leaves me unconvinced,” Voss comments. “Amazon Indians routinely overdifferentiate the large animals they hunt.” To support his point, Cozzuol received help from ethnozoologist Hugo Fernandes-Ferreira, who is expected to complete his doctoral dissertation this year at the Federal University of Paraíba on the history of hunting wild animals in Brazil. Fernandes-Ferreira explains that the overdifferentiation to which Voss refers is the tendency of indigenous people to assign different nomenclatures to animals they identify with different appearances, but that are actually only variations within the same species.

An example can be seen in light and dark jaguars, which belong to the same biological species but are considered different animals by most people in the Amazon. Tapirs, however, are hunted for their delicious meat and for parts of the animal that have medicinal, magical or religious uses. “People more carefully analyze animals they consider useful,” says Fernandes-Ferreira. “In addition, this differentiation between a large gray tapir and a small black one is widespread among nearly all Amazonian peoples.”

“I’ve always heard Indians, rubber tappers and farmers say there are two species of tapir,” Cozzuol says. “The Uru-Eu-Wau-Wau Indians, for example, live in an area where there is only one type of tapir, but they say that they know there are two types in other places.”

From other times
Fernandes-Ferreira also found historical records of hunters and naturalists mentioning two species of tapir in Brazil. The oldest is from 1794, in which Brazilian naturalist Alexandre Rodrigues Ferreira reports to the Portuguese crown about the existence of two species of tapir in the province of Grão-Pará, which is now the state of Amazonas.

Another significant historical account comes from U.S. President Theodore Roosevelt, who mentions in his reports of a 1912 visit to Brazil that he hunted a tapir in Mato Grosso, “a bull, very much smaller than the animal I had killed,” and that “the hunters said this was a distinct kind.”

The tapirs killed by Roosevelt were donated to the AMNH and analyzed in 1914 by zoologist Joel Allen, who considered the smaller animal to be just a variation of T. terrestris. “We had access to the measurements of that specimen, and they perfectly match what we expected from T. kabomani,” Cozzuol says.

“The position we will advocate on the IUCN panel is that, if there is the slightest possibility that a different species exists and we ignore it, we could end up condemning an important part of Amazonian biodiversity without even having known it properly,” Cozzuol explains. “In New Zealand, there was a similar case with the tuatara, a kind of primitive reptile related to the lizards. It was thought to be a single species, until conservation measures that worked in some areas failed in others. It was because there were actually two species of tuatara with different requirements.”

“Yes, if there really are two valid species of Amazonian tapir, then they should be managed separately,” Voss agrees. “On the other hand, since there is no effective management strategy for any Amazonian mammal, habitat protection seems to be the best approach.”

Scientific articles
COZZUOL, M. A. et al. A new species of tapir from the Amazon. Journal of Mammalogy. v. 94, n. 6, p. 1331-45. Dec. 2013.
VOSS, R. S. et al. Extraordinary claims require extraordinary evidence: a comment on Cozzuol et al. (2013). Journal of Mammalogy. v. 95, n. 4, p. 893-8. Aug. 2014.
COZZUOL, M. A. et al. How much evidence is enough evidence for a new species?Journal of Mammalogy. v. 95, n. 4, p. 899-905. Aug. 2014.

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