The idea that birds descended from dinosaurs is quite old and was first proposed by Huxley Since that time there has been a hot debate about avian origins see Witmer for a review , which has still not completely ended e. Nevertheless, the findings of several new specimens, which include "feathered dinosaurs'' from Late Jurassic or Early Cretaceous strata of China Caudipteryx and Protoarchaeopteryx that occupy a more basal position in the Maniraptora than Archaeopteryx Ji et al. The clade Aves follows the traditional use of the term "bird'' and can be defined as a group formed by all the descendants of the most common ancestor of Archaeopteryx and modern birds.
Most synapomorphies of Aves are found in the hand and wrist Sereno The oldest record of this group is still Archaeopteryx discovered in the Late Jurassic Strata of Solnhofen, southern Germany. From there on this group became gradually more diversified, particularly in the Cretaceous with the Enantiornithes Chiappe Despite being present since the Jurassic, birds were not the most common volant vertebrates during the Mesozoic, but are outnumbered by pterosaurs in the quantity of specimens and diversity.
It is also interesting to note that where pterosaur remains are common, birds are either absent or extremely rare, particularly in deposits formed near the ancient shorelines. The fact that the Enantiornithes, perhaps the most diversified Mesozoic group of birds were recovered mainly from continental deposits Chiappe seems to support this hypothesis.
Dinosaur Systematics Approaches and Perspectives Vertebrate Biological Sciences
No osteological materials of Brazilian Mesozoic birds were recovered so far. All have been regarded as avian, but the recent discoveries of feathered dinosaurs cast some doubts about those identifications. Scale bar: 1mm. Observe the dark and lighter bands, indicating the color pattern. Scale bar: 5mm. The down feathers e. The same is true for the only recorded flight feather, since the strong asymmetry of the vanes is more consistent with a good flying avian animal Fig.
The nature of the remaining feathers is inconclusive, but, to our knowledge, semiplumes are also not known in non-avian maniraptoran dinosaurs. Contour feathers could belong to birds or non-avian theropods, although none showing the color pattern were reported in feathered non-avian dinosaurs. In any case, the feathers found in the Crato Member indicate that early birds already possessed an effective thermoregulatory insulation cover with down feathers Kellner et al.
Those specimens further show that some animals dinosaurs or birds also had developed a distinct color pattern in their contour feathers, which in modern birds play several roles, particularly in behavior and communication. Likely these or similar kinds of mechanisms were present in the dinosaur evolutionary history. Ichnofossils are defined as any record preserved in the rocks that indicates the activity of one organism.
Dinosaur Systematics: Approaches And Perspectives
Therefore, once present, they tend to be found in comparatively large quantities. In Brazil dinosaur traces are present in several basins see Leonardi for a review.
One of the most recent reports were the discovery of dinosaur footprints in the more basal stratigraphical unit of the Araripe Basin, called Cariri or Tacaratu Formation Carvalho et al. Braun Fieldwork in the area done by one of the authors in Kellner , however, did not identify any structure that could be referred to dinosaur footprints. Unfortunately no casts are available of those supposed dinosaur footprints. Therefore, although those strata might be indeed Cretaceous in age Berthou , there is presently no conclusive paleontological evidence for that.
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Some of those tracks are regarded as belonging to ornithischian dinosaurs Fig. The identification of those tracks are not very easy and in some cases their affinities had been reinterpreted e. Those tracks were found in the strata of the Sousa Formation: 1 - Sousaichnium pricei Leonardi , attributed to Iguanodontidae; 2 and 3 - Moraesichnium barberenae Leonardi , attributed to a theropod; 4 - Staurichnium diogenis Leonardi , attributed to Iguanodontidae from Leonardi Trackways 1 and 4 are regarded as evidences of the presence of Ornithischian dinosaurs in Brazil Leonardi , Also regarded as ichnofossils but less common are dinosaur eggs.
They are found in several parts of the world and their study has advanced very much in the last decades e. In Brazil there are only two published reports of such fossils. The first one consists of a rounded, comparatively large egg referred to titanosaurs, which was found in Mangabeira, north of Uberaba, Minas Gerais Price The second consists of three elongated eggs Fig.
In this chapter we summarize the information regarding dinosaur localities from Brazil Fig. We do not include in this list the localities with ichnofossils except eggs that were already recently listed and discussed by Leonardi The information is presented here according to the geological age, geographic location, and lithoestratigraphic unit.
All published and some unpublished records are listed and, where pertinent, commented.
Santa Maria Formation 1. Alemoa, Santa Maria Colbert Theropoda Staurikosaurus pricei Colbert The specimen consists of an incomplete skeleton formed by lower jaws, cervical, dorsal, sacral and caudal vertebrae, part of scapula and humerus, pelvis, femura, tibiae, and fibulae, collected by Llewellyn Ivor Price in Dinosauria incertae sedis Spondylosoma absconditum Huene The specimen consists of the distal part of left scapula, proximal end of right humerus, distal part of left femur, fragment of left tibia, and eight vertebrae.
Huene has regarded it as a saurischian, but its dinosaurian nature has been questioned Sues Colbert mentioned that two laterally compressed serrated teeth might be associated with this specimen. Wald Sanga on the outskirts of the town Santa Maria Langer et al. Sauropodomorpha Saturnalia tupiniquim Langer, Abdala, Richter and Benton Three incomplete skeletons lacking the skull that are regarded as belonging to a primitive sauropodomorph.
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The close relationships of this taxon within this clade, however, are yet to be established. Caturrita Formation 4.
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Theropoda incertae sedis Guaibasaurus candelarai Bonaparte et al. One consists essentially of an incomplete skeleton with dorsal and caudal vertebrae, incomplete pelvis, and parts of the hind limbs; the second is an incomplete hind limb. Due to the anatomical characteristics of the foot, a prosauropod nature of Guaibasaurus cannot be disregarded at this point.
The material consists of the most complete Triassic dinosaur collected from Brazil so far including an incomplete skull and is being presently prepared and studied Azevedo et al.
Crato Member, Santana Formation 6. Down feather Kellner et al. So far the only dinosaur material known from the Crato Member are feathers, first reported by Martins Neto and Kellner About two dozen of feathers from this unit have been found, but the exact site where they were collected is unknown. In the past, all outcrops of the Crato Member were located around the town of Nova Olinda and were mined for industrial and construction purposes, leading to the suspicion that all published specimens have come from this area.
However, with the expansion of the quarrying activities in this region, several new mining pits were opened around Santana do Cariri and along the road Nova Olinda - Santana do Cariri. Therefore it is likely that some new specimens might have come from those.
In any case, there are several sites where feathers are found around Nova Olinda. Romualdo Member, Santana Formation 7. Theropoda, Spinosauridae Irritator challengeri Martill et al. The only site reported in the literature is the Ladeira do Berlenga , where Price collected the holotype of the crocodilian Araripesuchus gomesii , still the only tetrapod known from this region. A recent exploratory expedition to this region was carried out by one of the authors Kellner , revealing that it is limited to one outcrop cut by a road.
Dinosaur Systematics: Approaches and Perspectives
Abundant fish material was collected there but it is unlikely that any dinosaur specimen or pterosaurs known so far comes from this site. The Pernambuco State shows several outcrops of the Romualdo Member, mainly at mines that quarry gypsum. Some are very rich in fossil fishes and show potential for the findings of tetrapods. However, very limited collecting was done in those areas so far and it is also unlikely that any dinosaur material presently known comes from this region.
This activity which under Brazilian law is illegal is done primarily around the towns and villages of Santana do Cariri, Porteiras, and Jardim. Based on the sediments where the dinosaur remains are preserved indicate that there are at least two localities. Specimens like Santanaraptor were found in beige-colored, poorly laminated calcareous nodules, which are very rich in ostracods and fish remains. Those correspond to the "Santana concretions'', which are very common around Santana do Cariri see Maisey Other dinosaur remains e.
This kind of concretions is found around the municipality of Porteiras. In any case, no typical "dinosaur bone-bed'' is known in any region of the Araripe Basin. Those reptiles are very rare, contrary to other fossil vertebrates like pterosaurs and for all fishes.
Itapecuru Formation Cenomanian - Santonian 9. Itapecuru Mirim River Ferreira et al. Theropoda indet Sauropoda indet Only teeth form the theropod material, while the sauropod specimen consists of a few incomplete remains, including vertebrae. The latter has been first interpreted as a theropod dinosaur Ferreira et al. Cretaceous Strata This is one of the few bone-beds known in Brazil.
Dinosauria indet. Bauru Group Titanosauria indet "Antarctosaurus'' brasiliensis Arid and Vizotto Dinosauria indet Isolated dinosaur remains Ihering Adamantina Maciel Ribs and femur Maciel Pacaembu Paulista Mezzalira Sauropod teeth Mezzalira Colina Pacheco Isolated femur Pacheco Some of those isolated remains were attributed to different European dinosaur taxa e.
Unfortunately the whereabouts of many of those specimens, particularly the older occurrences, is unknown. State of Minas Gerais Uberaba Formation Upper portion of the Bauru Group Titanosauridae indet. Uberaba Price Several isolated titanosaurid remains.
This town is actually build over fossiliferous rocks of the Bauru Group. Mangabeira, north of Uberaba Price One titanosaurid egg Price Isolated remains of titanosaurids Price Morro da Galga, close to Uberaba. Ponte Alta, 35 km East of Uberaba. Road about 45 km between Campina Verde and Prata. Titanosaurid remains Henriques et al.