The Brazilian Galapagos
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_ EVOLUTION The Brazilian Galapagos Lizards from the sand dunes of the São Francisco River – some resembling snakes – express their own evolutionary histories Carlos Fioravanti hirty-two years after his first expe- From the very first trip he brought back a new dition to the sand dunes of the São species of lizard, today called Eurolophosaurus Francisco River, biologist Miguel amathites, which lives only there. On other expe- Trefaut Urbano Rodrigues, from the ditions, he and his team found animals that had University of São Paulo (USP), is still never been described, like a two-headed snake Tsurprised at “that crazy fauna,” as he puts it. and a subterranean snake, both with sister spe- In 1980, when he was 27 and even thinner than cies from the other side of the river. In the dunes he is today, he traveled under a merciless sun of the Brazilian Sahara, an area that measures throughout Santo Inácio, a city then made up 7,000 km2 and stretches along 120 km of river, of 200 inhabitants in northern Bahia state, and the team already identified nearly 30 species was astonished by the diversity of similar ani- and eight new exclusive genera of lizard (exclu- mals: the sister species had only small differences sive to the area), which is more than in all the in appearance or genetic make-up. The nearly deserts of North America or Africa. There, and identical creatures lived in the sand dunes on only there, lives a rodent that measures 20 cm, either side of the river. They had differentiated the rabo-de-facho (spiny rat), as well as a bacurau from a common ancestor and followed their own (nightjar) that measures 20 cm high, similarly S UE G I evolutionary paths from the time that the river adapted to the sand dunes of the São Francisco. R – which at that particular point is only 200-300 These dunes display a biological diversity that UEL RODUEL G meters wide – came to separate them. is comparable to the Galapagos archipelago, on MI 94 _ SPECIAL EDITION FAPESP 50 YEARS whose fauna Darwin based his development of She, along with Rodrigues and colleagues from the theory of human evolution. Yale University, presented these conclusions in In recent years, Rodrigues and his team of 20 the journal Evolution in 2006. They received so researchers have been explaining the genetic and much criticism that they had to publish a coun- evolutionary mechanisms that guided the dif- terargument in 2010, in an article that also ap- ferentiation of lizards measuring no more than peared in Evolution, as a way to settle the debate. 5 cm in length. The oldest species of the same “Based on the tools of statistical analysis we de- taxonomic genus of lizards still look like lizards; veloped,” Kohlsdorf says, “groups from other they have short bodies and, shall we say, normal countries began to show reversion of wings in limbs. The species that began to form over the insects and other animals.” last thousand years or so, however, started los- While the debate raged on, the USP biologists ing digits. Their limbs shrank or disappeared, confirmed that in at least two genera of lizards and their bodies became elongated, to the point exclusive to the sand dunes, Calyptommatus and where some species of lizards look like snakes Nothobachia, the loss of limbs is irreversible. The except for the small appendages that would have animals had only miniscule appendages of what been the front feet of their distant ancestors. the limbs had been and were similar in appear- The biologists believed that the loss of complex ance to snakes. Kohlsdorf admits, “We don’t structures like the limbs was irreversible – it is know why only the Bachias were able to reverse the so-called law of irreversibility of evolution, or the loss of limbs.” Dollo’s Law, in honor of Belgian naturalist Louis Juliana Rossito, a researcher in Rodrigues’ Dollo, who presented the theory in 1890. Howev- group, examined embryos and adults of the genus er, one of the lines of lizards with smaller limbs Calyptommatus at various stages of development showed that it is possible to get the limbs back. to understand how the loss of limbs might have Life in the sands of In collaboration with Rodrigues, Tiana Kohlsdorf, occurred. She observed that in the embryo, the northern Bahia state, along with her team from USP Ribeirão Preto, femur begins to form between the fifth and six- with and without studied 15 species of lizards of the genus Bachia teenth days, but then it disappears. Her analyses feet (from left to right): Tropidurus that live throughout South America. The oldest indicate that this genus of lizards is ready to be amathites from Santo among them had limbs with five toes and the more born in one month – and not six, as in the case Inácio; Nothobachia recent had four, then three, then two – and then of the closest species – perhaps as a result of ablephara and S three again. “There is a reversal, since the genetic the effects of temperature or the scarcity of wa- UE Calyptommatus G I R leiolepis from information was not lost, but rather, it evolved ter. Rodrigues adds, “This species found a way Alagoado; Tropidurus again, because the toes that reappeared are not to accelerate its development through natural UEL RODUEL G pinima from Santo MI exactly the same, “ says Kohlsdorf. selection.” Inácio PESQUISA FAPESP _ 95 ccording to Rodrigues, the reduction in the ards by comparing 10 genes. DNA analyses often number of feet and the elongation of the indicate that the analyses obtained on the basis Abody may have occurred during the evolu- of external features need to be revised. tionary history of lizards of the family Gymnoph- Rodrigues and his work group are seeing how talmidae, made up of 45 genera, including Bachia restricted environments are able to limit the de- and Calyptommatus, as a result of adaptations that velopment of new species with unique character- allowed them to avoid extreme temperatures. This istics and habits. The creatures that live in the process gave way to species that were able to bury sand dunes are so specialized that they do not themselves in order to escape predators, as well survive in – or even venture into – the neighbor- as the cold and heat, which can reach 50°C in the ing caatinga. Animals that are typically found sand. It is estimated that this process must have in the caatinga, in turn, only marginally venture occurred at least two dozen times throughout the into the sand dunes. Even among the animals history of these lizards. This in turn advanced themselves, specialization into different envi- the origin of unique and at times even repugnant ronments occurred. Some species of lizards live lizards as well as a group of animals with its own only on clusters of rocks and do not traverse the habits, famous in its own right – the snakes. caatinga areas that separate the rocky outcrops. In order to understand how and why the lizards are becoming able to live buried in tunnels or caves, FROM THE OTHER siDE OF THE ATLANtic Agustín Camacho filmed and analyzed hundreds Rodrigues observed the same phenomenon – iso- of tests that compared the locomotion, the abil- lated populations of Platysaurus, lizards from an- ity to escape and the feeding habits of 12 species other family, but who are very similar in appear- of lizards of the family Gymnophtalmidae using ance to those of one of the groups of Tropidurus, cameras placed in sand inside the laboratory. “The who also have flattened bodies and live only among elongated body and absence of feet seem to favor the stones – in Mozambique, where he went for the development of the fossorial lizards that are the first time in 2007. His plan is to go back there able to escape predators more quickly, feed more in 2013 to conduct a survey of lizards and snakes and bury themselves more easily than those with in the north and south of Mozambique in the com- feet,” he concluded. “But it’s still not possible to pany of other Brazilian and Mozambican biolo- say which morphotype is better adapted to life in gists. They want to see if the genera of this lizard the sand, because even the species with four feet population in Africa originated at the same time is abundant. They survive well and are seen by the as those in Northeastern Brazil. If so, biologists dozens in the sand dunes.” According to him, desert may be able to tell parallel stories of lands that lizards of Australia lived a similar evolutionary life. were close together millions of years ago. Camacho represents the second generation of biologists on the trail of strange creatures in the sands of northern Bahia state. He studied biology The lizards of Bahia in Andalusia, Spain, but “was passionate about coming to the tropics,” he says. He traveled to PERNAMBUCO PIAUÍ São Paulo in 2002 for a short course on venom- Toca da Cabocla ous animals and lizards, returned to Spain to fin- (Serra das Confusões) ish his studies, and in late 2003 moved to Salva- dor, Bahia, to work on his master’s degree at the Federal University of Bahia. His advisor, Pedro Alagoado Rocha, had completed a doctoral degree on the ecology of the lizards in the São Francisco sand Rio São Francisco dunes, advised by none other than Rodrigues. In late 2007, Camacho moved to São Paulo and is now pursuing his doctoral degree in an office BAHIA one floor above that of Miguel Rodrigues.