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1.
《Gondwana Research》2006,9(4):473-477
Titanosaur remains are common findings at the paleontological site of Peirópolis in Uberaba. Among those remains, two osteoderms referred to titanosaur sauropods were reported. Both dermal bones share many features, such as the coarse texture, parallel ventral grooves, lack of the cingulum and presence of a ventral ridge (crest). Armored titanosaurs had wide distribution in the Upper Cretaceous, and have been reported from Argentina, Brazil, France, Madagascar, Malawi, Romania and Spain. In the present work we describe and compare the Brazilian titanosaur osteoderms found thus far. 相似文献
2.
Titanosaur remains are common findings at the paleontological site of Peirópolis in Uberaba. Among those remains, two osteoderms referred to titanosaur sauropods were reported. Both dermal bones share many features, such as the coarse texture, parallel ventral grooves, lack of the cingulum and presence of a ventral ridge (crest). Armored titanosaurs had wide distribution in the Upper Cretaceous, and have been reported from Argentina, Brazil, France, Madagascar, Malawi, Romania and Spain. In the present work we describe and compare the Brazilian titanosaur osteoderms found thus far. 相似文献
3.
The upper Campanian-lower Maastrichtian site of Lo Hueco (Cuenca, Spain) has provided a set of well-preserved partial skeletons in anatomical connection or with a low dispersion of their skeletal elements. One partial skeleton is herein described and a new titanosaurian sauropod is established, Lohuecotitan pandafilandi. This titanosaur is diagnosed by eight autapomorphic features: dorsally and ventrally widened or bifurcated posterior centrodiapophyseal lamina in anterior and middle dorsal vertebrae; short postspinal lamina with a transversely expanded distal end represented by smooth scars in the dorsal vertebrae; anteriormost caudals with the medial spinoprezygapophyseal and medial spinopostzygapophyseal laminae ventrally connected with the prespinal and postspinal laminae, respectively; anterior caudal neural spines with a dorsal projection of the prespinal and postspinal laminae; anterior caudal neural spines bears a “greek-cross”-like cross-section; middle caudal centra having two round and rough structures in the dorsal edge of the posterior articulation, which extends to the dorsal surface of the centrum; the articular ends of the rami of the haemal arches are divided in two articular surfaces; and tuberosity between the anterior and the lateral trochanter of the fibula. The herein performed phylogenetic analysis considered L. pandafilandi as a member of Lithostrotia more derived than Malawisaurus. The known palaeodiversity of the Late Cretaceous Ibero-Armorican titanosaurs is increasing, and further analyses focused on this group will be necessary to better understand the evolutionary history of European titanosaurs and to clarify their relationships within Titanosauria. 相似文献
4.
We describe a juvenile specimen of a titanosaurian sauropod dinosaur consisting of two dorsal and three caudal vertebral centra, an ilium fragment, and an ischium unearthed in 1991 from Site Km 153.5 at BR-050 highway in the Serra da Galga region, municipality of Uberaba, state of Minas Gerais, Brazil. The outcrop at the site is assigned to the Serra da Galga Member of the Marília Formation (Bauru Basin: Bauru Group; Upper Cretaceous: Maastrichtian). Although the material is very incomplete, features such as strongly procoelous caudal centra suggest an affinity with the titanosaurian clade Lithostrotia. The extensive vertebral pneumaticity with deep pleurocoels and well-developed camerae supports the hypothesis that, in titanosaurs, the air sac system was already present and fully developed even at early ontogenetic stages. 相似文献
5.
Among titanosaurs, osteoderms are morphologically diverse and have been reported from deposits in South America, Africa, Madagascar, Eurasia and Oceania. In Brazil, titanosaur osteoderms are rare and have only been recorded from Bauru Basin sedimentary rocks. Here, we describe a keeled titanosaur osteoderm, which is the first occurrence of an osteoderm specimen in the São Luís Basin, Northeastern Brazil. This osteoderm is characterized by an external bulb, an internal root, and a very rugose cingulum limiting the external and internal surfaces. These characteristics are typical of Titanosauria dermal bones, and this specimen strengthens the idea that the armored sauropods were present during the early Late Cretaceous of Northeastern Brazil, extending their distribution in the northernmost portion of South America. 相似文献
6.
An isolated titanosaur femur recovered from the Javelina Formation (Maastrichtian) of Big Bend National Park, Texas is the most complete example yet reported from North America. The specimen is likely referable to Alamosaurus sanjuanensis, the only titanosaur thus far known from Upper Cretaceous strata in North America, but cannot be attributed with certainty to that taxon. Compared to femora from other titanosaurs, the specimen has a relatively reduced abductor crest, a less elevated femoral head, and a distal joint surface that is orthogonal to the long axis of the shaft. These differences suggest that the Big Bend femur pertains to a species where hindlimb stance was closer to vertical, and with a comparatively narrower gait than other titanosaurids. 相似文献
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There are 24 known localities for skeletal remains of sauropod dinosaurs in the republics of Central Asia (Kazakhstan, Kyrgyzstan, Tajikistan, and Uzbekistan). Sauropod remains are very rare at all these localities and represented usually only by isolated teeth. Only narrow-crowned teeth are known from the Cretaceous of Central Asia. The oldest record of such teeth is from the Aptian Sultanbobo Formation of Uzbekistan. Exposures of the Turonian Bissekty Formation at the most productive vertebrate locality in the region, Dzharakuduk in Uzbekistan, has yielded many isolated teeth and a few skeletal remains that can be attributed to a non-lithostrotian titanosaur. Similar narrow-crowned, cylindrical teeth from Cenomanian-to Coniacian-age strata in the Kyzylkum Desert, Uzbekistan, may belong to a closely related taxon. Another taxon, with teeth that are pentagonal in cross-section, is known from the Santonian Yalovach and Bostobe formations of Tajikistan and western Kazakhstan, respectively. A femur reported from the Santonian Syuksyuk Formation of southern Kazakhstan possibly belongs to a lithostrotian titanosaur. The change in tooth structure at the Coniacian–Santonian boundary in the region possibly suggests replacement of non-lithostrotian titanosaurs by lithostrotians. The titanosaur from the Bissekty Formation is similar to Dongyangosaurus sinensis from the Cenomanian–Turonian of Zhejiang (China) in the extensive pneumatization of the neural arch on the anterior caudal vertebrae with several fossae. It also resembles Baotianmansaurus henanensis from the Cenomanian of Henan (China) in the possession of very short anterior caudal centra. These three taxa possibly represent an as yet formally unrecognized endemic clade of Asian non-lithostrotian titanosaurs. 相似文献
9.
Saltasaurine titanosaurs are characterized by their relatively small size compared to other sauropods, extreme postcranial pneumaticity, and dermal armour covering the body. This group has been reported in the Upper Cretaceous of the Lecho, Allen, and Anacleto formations of Argentina. We describe here a new saltasaurine specimen (MACN-Pv RN 233) from the Campanian of the Angostura Colorada Formation (Río Negro Province) that is represented by eight caudal vertebrae and six osteoderms. This specimen is described in detail and its phylogenetic relationships with the other three known saltasaurines, as well as its implications to the knowledge of caudal vertebra and osteoderm anatomy, are discussed. Our results place MACN-Pv RN 233 more closely related to Saltasaurus loricatus and Rocasaurus muniozi than to Neuquensaurus australis. MACN-Pv RN 233 possesses a combination of features that differ from other saltasaurines, but because of the fragmentary nature of the specimen we decided for the sake of taxonomic stability to not erect a new taxon. This specimen shows the first unambiguous evidence of chevron pneumatisation for a sauropodomorph, implying a broader osteological invasion of the diverticula from the abdominal air sac than previously thought for this group of dinosaurs. MACN-Pv RN 233 preserves two osteoderm morphotypes, one similar to those reported for Neuquensaurus australis and Saltasaurus loricatus. This new specimen expands the distribution of the group to a new geological unit and increases the dinosaur diversity known for the Angostura Colorada Formation. 相似文献
10.
The Late Cretaceous (Santonian) continental vertebrate locality of Iharkút, western Hungary has provided numerous azhdarchid pterosaur remains including the recently described, Bakonydraco galaczi. Since the first report of these fossils, additional remains have been discovered that improve considerably our knowledge of some aspects of the anatomy of azhdarchid pterosaurs. New cranial material described here indicates an edentulous, non-crested premaxillary rostrum in Bakonydraco similar to that of Quetzalcoatlus and reveals that this rostrum was considerably thinner and more lightly built than the relatively massive, pointed mandibular symphysis. In addition, the contact surface of the upper and lower jaws of Bakonydraco at least in the symphyseal region was more similar to Tapejara wellnhoferi than to other azdarchids: the contact is irregular and the premaxilla does not fit closely the rostral part of the mandible. Among the postcranial material the atlas-axis complex possessing lateral pneumatic foramina is of great importance because it further supports the notion of interspecific variability of vertebral pneumaticity among pterosaurs. 相似文献
11.
Dental histology of periodontal tissues (cementum, periodontal ligament and alveolar bone) has been studied in mammals, crocodylians and some basal tetrapods, but these structures have never been studied in titanosaur sauropods. The goal of this work was to study the structures of dental insertion in Titanosaurs. Like many physiological processes, histological analysis of titanosaur teeth shows hard tissue formation, characterized by a circadian rhythm. From thin sections it was possible to observe microstructures such as incremental lines of von Ebner, dentinal tubules and cross striations, all key to the understanding of developmental tooth dynamics. The structural and histological analyses carried out here on teeth of Late Cretaceous titanosaurs reveals the presence of acellular and cellular cementum, periodontal ligament, and alveolar bone, all structures necessary for a truly thecodont dentition. This is the first time documented for a dinosaur via histological tissue, and is an important finding that will help elucidate aspects of dinosaurian dentition, tooth replacement rate, feeding strategy, metabolism, and general biology. 相似文献
12.
Saurabh Pal 《Geology Today》2023,39(1):31-35
Titanosaurs were a globally distributed group of sauropod dinosaurs. They had diverse forms and a wide-gauge stance, with a few of their species reaching immense sizes, such as Argentinosaurus huinculensis and Patagotitan mayorum (reaching >35 m in length). There are about 100 valid titanosaur species known so far, but most of the originally described species are no longer valid, due to the incomplete nature of fossil materials. Our understanding of titanosaur skull morphology is based on very few incomplete fragmented cranial materials and findings of the complete skull are even rarer. Understanding the skull morphology of extinct animals helps palaeontologists make deductions of feeding mechanisms and also provide an idea about their appearance when they were alive. Diversity in titanosaur skull morphology is greater than that of any other sauropod clade, indicating diversity in feeding mechanism among these dinosaurs. Titanosaurs were the last surviving clade of sauropod dinosaurs, occupying nearly every ecological niche around the world during the Late Cretaceous, and resulting in a rich diversity in this group. This article highlights diversity in the basic structure of sauropods with special emphasis on titanosaur skull morphology. 相似文献
13.
Here we describe the first sauropod skeletal remains from the Italian peninsula that also represent the earliest record of titanosaurs in Southern Europe. Scattered bones, including an almost complete anterior caudal vertebra, were found in Cretaceous (Aptian–Albian) marine deposits, some 50 km East of Rome. The vertebra shows a bizarre and perhaps unique orientation of the zygapophyseal articular facets that renders their interpretation problematic. Phylogenetic retrofitting tests support the placement of the Italian titanosaur among basal lithostrotians. Palaeobiogeographic analysis based on the resulting phyletic relationships suggests an Afro-Eurasian route for the ancestors of the Italian titanosaur, a scenario compatible with the palaeogeographic evolution of the Italian microplates during the Cretaceous. Together with previously recorded titanosaurian-like ichnites from a Cenomanian locality in Latium, this new find suggests a quite long emersion for the Apenninic carbonate platform. We suggest that the Italian titanosaur was member of a population that crossed the western Tethys Sea through a “filtering bridge” composed of a chain of ephemeral islands and peninsulae, known as Periadriatic (Adria) carbonate platforms, that connected sporadically Africa and Europe since the Early Cretaceous. 相似文献
14.
The idea that titanosaurs had osteoderms was proposed in the late nineteenth century by Depéret. However, this idea was given little credence by other researchers until 1980 when unequivocal evidence of armoured titanosaurs was reported. Since then, many discoveries of titanosaurian osteoderms have been made worldwide. In this work, seven osteoderms are described from the Allen Formation (upper Campanian–lower Maastrichtian), Salitral Moreno locality, Río Negro Province, Argentina. Among the described osteoderms it was possible to recognize three morphologies (keeled, ellipsoidal and cylindrical), with the first of these being most prevalent. Although the osteoderms from Salitral Moreno resemble osteoderms found in other parts of the world, no osteoderms of a similar morphotype are known from this locality, or from Lago Pellegrini or Cinco Saltos. 相似文献
15.
We evaluated 193 K-Ar ages (10 newly determined) of basaltic and differentiated rocks of the Serra Geral (Paraná) flood-basalt province for indications of magmatism occurring systematically with progressive rifting and complete separation ( ≈130-105 Ma) of South America from Africa. The K-Ar ages represent basalt emplacement between 35° and 19°S covering about 1,200,000 km2. We note that volcanism appears ubiquitous across the province between about 140 and 115 Ma, and that there are no significant age differences within that relate directly to progressive south-to-north tectonism. On the other hand, the oldest samples, about 140–160 Ma, are among those nearest the Brazil coastline (rift margin), perhaps suggesting migration of activity away from the rift with time. Studies of other flood-basalt provinces now indicate short (<3 m.y.) eruption periods, thereby pointing to the need for re-examination of Serra Geral ages by 40Ar-39Ar incremental heating techniques. 相似文献
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Within the past decade exceptional preservation of original organic components have been reported from several dinosaurian families, including members of Sauropodomorpha. Here we document the partial preservation of a vertebral ligament in the dorsal and sacral series of a titanosaur. Unlike other cases of tissue preservation, this structure does not represent biomineralization of the original organic components. Histology, morphology, and comparative anatomy from extant taxa as well as the preferential placement on the vertebral column suggests that it represents the partial preservation of the nuchal ligament. While preservation of other sauropod connective tissues are known, this case represents the first reported non-biomineralized tissue from a sauropod. In consideration of the location and external and internal morphologies compared to modern vertebral ligaments, we believe this structure to be the micritic replacement of the original tissue via microbially-mediated processes. Along with the suggestive external morphology, internally we interpret some of the unusual structures to represent the remnants of the collagen and elastin fascicles that are strongly overprinted by a clotted, thrombolytic-like fabric recording microbial activity and deposition of micrite prior to lithification. In consideration of the interpreted depositional history, we theorize that post-deposition, bacteria deposited the micrite as a byproduct of metabolization. Subsequently, the recognition of this structure as a vertebral ligament, the largest of such thus documented, substantiates previous findings on the morphological attributes of sauropod vertebral ligaments. 相似文献
18.
The Serra Pelada Au-PGE-rich deposit is located in the Serra dos Carajás, a leading mining area in Brazil. This region is characterised by a complex geological and structural framework and is affected by deep lateritisation which has lasted for more than 70 Ma. The Serra Pelada deposit is emplaced in a late-Archean low-grade metasedimentary sequence (Rio Fresco/Águas Claras Formation) which is host to other gold deposits in the region (Igarapé Bahia, Águas Claras). The Rio Fresco/Águas Claras sequence was deposited in tectonic basins developed on Archean basement and Au-bearing greenstone terranes which were intruded by PGE-rich layered mafic complexes (e.g. Luanga). The Serra Pelada mineralisation is located along a regional, complex system of strike-slip faults (Cinzento-Carajás systems) which were active during the late Archean to early Proterozoic. The mineralisation appears to be concentrated along a faulted hinge zone of a fold. Ore zone rock facies are dominated by low-grade ferruginous to carbonaceous metasiltstones and minor sandstones, locally brecciated and cemented by quartz (-sulphide) stockwork. Supergene alteration led to partial to total transformation into friable aggregates of kaolinite, Fe oxide-hydroxides, silica and secondary phosphate-sulphates even at depths exceeding 200 m. Precious metals are exceptionally enriched, with up to more than 1,000 ppm Au+PGE in some peculiar ferruginous-graphitic zones locally called "hidrotermalito". Geochemistry shows complex patterns of major and trace elements, particularly rare-earth elements (REE), in mineralised vs. nonmineralised samples. These patterns are interpreted in terms of variable degree of superposition of hydrothermal and supergene alteration. Precious metals show progressive increase from samples with hydrothermal imprint to samples with supergene imprint. The geological evolution of the Carajás region and the characteristics of mineralisation at Serra Pelada may suggest a composite mineralising process: hydrothermal activity (by fluids likely originated from granitoids) was followed by supergene alteration during long-lasting lateritisation to develop extreme precious metal enrichments in a geological context probably already anomalous for Au and PGE. 相似文献
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Sclerorhynchiform sawfishes are a diverse and extinct clade of elasmobranchs that is restricted to the Cretaceous. Most taxa are known only by isolated rostral spines, whereas skeletal remains are rare and have been reported from a small number of Upper Cretaceous localities. Here, we describe skeletal remains of the giant sclerorhynchiform Onchosaurus pharao for the first time, which provides new morphological information. The single specimen comes from middle-basal upper Turonian strata of the Lessini Mountains in northeastern Italy and represents the first record of this genus from Italy. The specimen consists of unidentifiable cranial remains, several diagnostic rostral spines, the rostrum with fragments of tessellated calcified cartilage, and 87 disarticulated vertebrae. The rostrum preserves the characteristic sensory system of sclerorhynchiforms. It is devoid of any lateral sockets indicating that rostral spines were attached laterally to its surface. This pattern is identical to most sclerorhynchiforms and extant pristiophoriformes implying also similar replacement patterns as in most other sclerorhynchiforms with the exception for Schizorhiza. Additionally, the bases of two longitudinally arranged rows of ventral rostral spines are identifiable concurring with patterns seen in Sclerorhynchus. The axial skeleton is partly preserved. Re-arranging the disarticulated vertebrae according to their life position in combination with measures of the size and thickness of preserved vertebral centra, and the ratio rostrum length/body size depending on the number of vertebral centra indicate that the specimen was ca. 450 cm long. Growth rings in the vertebral centra show that the specimen was about four years old and thus probably not yet fully sexual mature when it died. This age assumption corresponds well with the calculated size when compared with complete skeletons of extinct sclerorhynchiforms and extant pristiforms. The size of the specimen and its occurrence in hemipelagic rocks corroborates previous assumptions that this sclerorhynchiform was a large and pelagic sawfish. 相似文献