Fossils on the Move

PALEONTOLOGY y Fossils on the move 5 cm 3D reconstructions highlight new characteristics of crocodiles and dinosaurs that lived millions of years ago in Brazil Diego Freire PUblISHed IN OCtobeR 2017 inding fossils is an important—and that terrestrial locomotion was com- More than a decade after participat- perhaps the most celebrated— mon among an extinct crocodile species ing in the discovery of Montealtosuchus part of a paleontologist's work; discovered in Monte Alto, São Paulo, arrudacamposi crocodile fossils, paleon- Fhowever, in many cases, this ac- in 2004. This hypothesis is based on tologist Sandra Simionato Tavares, direc- tivity is only the first step in an intense anatomical analysis of the limbs of the tor of the Monte Alto Museum of Pale- effort to interpret the echoes of a past reptile, which lived 80 million years ontology, recreated the animal's muscle so distant that they are almost inaudible. ago. Another study by paleontologists system and joints. In partnership with Two recent studies by Brazilian teams from the Brazilian states of São Paulo researchers from the Institute of Radi- have shown how three-dimensional im- and Minas Gerais and from Germany ology at the University of São Paulo’s ages produced by tomography can be reconstructed the brain of a 230-million- School of Medicine (FM-USP), she ob- used to reinterpret the habits and char- year-old dinosaur found in Rio Grande tained tomographic images of different acteristics of known fossils, enabling do Sul State, Brazil, in the 1990s. In the parts of the fossil comprising skull frag- researchers to digitally reimagine the corresponding article, the authors argue ments, vertebrae, and a front limb. These probable movements of animals that that the dinosaur’s neck was so flexible, images were sent to research partners lived hundreds of millions of years ago. the species may have been carnivorous, at the Renato Archer Information Tech- A paper by paleontologists from rather than strictly herbivorous, as is nology Center (CTI) and the National São Paulo and Rio de Janeiro suggests typical of its genus. Synchrotron Light Laboratory (LNLS), 60 z DECEMBER 2018 both in Campinas, São Paulo, who were Tomographic able to recreate the reptile's movements images of the Montealtosuchus in a virtual environment. The results arrudacamposi of this study, which included work by crocodile and Fresia Ricardi Branco from the Insti- skeleton assembled tute of Geosciences at the University of using fossils of Campinas (UNICAMP), were published the reptile in the journal Cretaceous Research in July this year. "The studied crocodile shares some characteristics with current species and others with its more distant ancestors," says Tavares. The mandibular joints of Montealtosuchus were similar to those of modern-day crocodiles. However, the nostrils of the extinct species were positioned at the front of the snout, and the eyes were located on the sides of the head, suggesting that Montealtosuchus inhabited terrestrial environments. By examining the tomographic images, the research group led by Tavares looked beyond the described morphological characteristics of Montealtosuchus and gained a new understanding of the bio- mechanics of the animal. The results of the analyses indicated that the limb posture of Montealtosuchus was more up- right than that of its present-day coun- terparts, which are largely aquatic. The extinct crocodile, which mea- RCH RCH ea sured between 1.3 and 1.5 meters long, S Re weighed 25 to 50 kilograms. The digital US US eo C reconstruction suggests that the joints in eta R the pectoral girdle and anterior appen- C . / dicular skeleton, which support posture 5 cm ET AL . and movement, were distributed so that S , , S E the limbs of Montealtosuchus could be R positioned vertically below the body and TAVA S not to the side. The 3D reconstruction PHOTO of the bones suggests that the scapu- PESQUISA FAPESP z 61 Skull bones of the Saturnalia tupiniquim dinosaur, which lived 230 million years ago It was thanks to advances in computed tomography that researchers from the University of São Paulo in Ribeirão Preto and the Ludwig Maximilian University of Munich were able to analyze in more detail the fossils of the bones that sur- round the brain, known as the neurocranium, of Saturnalia tupiniquim. Found 1 in rocks from the Triassic period in the 20 cm Brazilian state of Rio Grande do Sul, S. tupiniquim is one of the oldest dinosaurs in the world. The species is part of the sauropodomorph genus, the a group that la, coracoid, and humerus were joined, includes the largest terrestrial animals and the metacarpals were more com- that ever inhabited the planet, namely, pressed and closer together than those long-necked herbivores that were up to of present-day crocodiles, meaning the Brain structure 40 meters long and weighed as much as extinct crocodile was able to travel long 90 tons. Unlike its more famous rela- distances on land in search of prey with- suggests that tions, however, the Brazilian dinosaur out depending on large bodies of water the Saturnalia was small, averaging approximately 1.5 or wet environments. meters in length. In addition to plants, was a predator S. tupiniquim may have eaten small ani- ur understanding of past life on mals. For S. tupiniquim, reconstruct- Earth must transcend the simple and not strictly ing the internal structure of the skull “Oknowledge of the diversity of ex- allowed scientists to estimate the size, isting forms of life," says paleontologist a herbivore shape, and formation of the brain, shed- Ismar Carvalho, who is from the Insti- ding light on the animal's eating habits. tute of Geosciences at the Federal Uni- The analyses provided additional evi- versity of Rio de Janeiro (UFRJ) and dence that earlier sauropodomorphs one of the coauthors of the paper. He may also have been predators. believes that evaluating the mechanics of movement and the physiology of extinct animals allows us to improve eco- 2 logical interpretations. "The anatomical and physiological solutions identified in animals reflect the ecological spaces in which they lived, but our knowledge is limited by difficulties in extracting information from fossils without dam- aging them. Tomographic images allow us to model muscle arrangements and insertions, aspects that are difficult to evaluate by simply observing fossil re- cords," he reports. Paleontological site in Rio Grande do Sul, Brazil, where the dinosaur was found 62 z DECEMBER 2018 3 Artistic aleontologist Sérgio Alex Azeve- reconstruction do, from the UFRJ National Mu- of the seum, who did not participate in dinosaur P and modeling the studies on the Monte Alto crocodile of its skull or the Brazilian dinosaur, believes that while the use of tomography in paleontological research is not new, the technique has become more effective with the development of higher-resolution technologies. The more sophisticat- ed equipment is capable of providing greater detail than medical CT scanners. With fossils, there is no need to worry about strictly controlling radiation lev- els, since no living organisms are being examined. "Tomography is a noninvasive technique that does not alter the form 4 of the object under analysis. This is fun- damental when dealing with materials at risk of natural deterioration, which Using digital reconstruction, research- According to Max Cardoso Langer, must not be subjected to mechanical ers filled in the fossilized neurocranium from the Department of Biology at USP's damage. The technique gives us access of S. tupiniquim and noticed that certain Ribeirão Preto School of Philosophy, to a whole range of previously unavail- areas, such as the flocculus and parafloc- Sciences, and Languages and Literature able information, such as the structures culus, which are part of the cerebellum (FFCLRP-USP), this is the first time that of internal cavities," he explains. n and are related to the control of vision parts of the brain of such an ancient di- and head and neck movements, certain nosaur have been digitally reconstructed. A IR areas were larger than expected. "Such "This study allowed us to better under- E Project U og developed structures suggest that the stand habits that are closely related to The origin and dispersal of dinosaurs in Gondwana (Neo- N O F animal may have exhibited behavior typ- the evolution of life on Earth and that triassic – Eojurassic) (No. 14/03825-3); Grant Mechanism ical of predators, who use rapid neck are usually inferred based only on the Thematic Project; Principal Investigator Max Langer Rodol (USP); Investment R$1,959,890.17. 4 morphology of teeth and other parts of D and head movements to catch small and N A Scientific articles 3 agile prey," says paleontologist Mario the skeleton," says the researcher, who p TAVARES, S. et al. The morphofunctional design of Mon- -R Bronzati Filho, the lead author of the was involved in the discovery of the di- P tealtosuchus arrudacamposi (Crocodyliformes, Upper US 2 article, which includes the results of the nosaur in the 1990s. Paleontologist Jon- Cretaceous) of the Bauru Basin, Brazil. Cretaceous Re- IR A analysis and was published in Scientific athas de Souza Bittencourt Rodrigues, search. July 11. 2017. N BRONZATI, M. et al. Endocast of the Late Triassic (Car- ay J Reports in September. Bronzati is cur- from the Federal University of Minas 1 nian) dinosaur Saturnalia tupiniquim: implications for the s rently studying a doctorate at the Lud- Gerais (UFMG), also participated in the evolution of brain tissue in Sauropodomorpha. Scientific PHOTO wig Maximilian University of Munich. Saturnalia study. Reports. v. 7, 11931, 20 Sept. 2017. PESQUISA FAPESP z 63.

Load more