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1.
A new ornithopod dinosaur from the Upper Cretaceous (Maastrichtian) Snow Hill Island Formation, at James Ross Island, Antarctica is here described. This new taxon, named as Morrosaurus antarcticus gen. et sp. nov., is represented by a fragmentary right hind limb belonging to a medium-sized individual. Our phylogenetic analysis nests the new taxon in a monophyletic clade of Southern Hemisphere ornithopods that includes most Patagonian and Antarctic ornithopods. Several members of this group share a slender and bunched foot with narrow metatarsal IV, expanded chevrons, and bowed humerus without deltopectoral crest. Several features indicate that these ornithopods exhibit adaptations for a specialized cursorial mode of life. The recognition of Patagonian and Antarctic Ornithopoda belonging to a monophyletic clade reinforces palaeobiogeographical signals indicating that Patagonia, Antarctica and Australia shared a common Late Cretaceous terrestrial fauna. 相似文献
2.
A complete and well-preserved right ankylosaurian humerus from the Upper Cretaceous (Santonian) Csehbánya Formation of Iharkút, western Hungary is described here. Based on its osteological features and 21.5 cm adult length, the new specimen is markedly different from the slender humerus of Hungarosaurus, the previously known ankylosaur from the locality, and more similar to that of Struthiosaurus. Thus, the new Hungarian specimen is tentatively assigned here to cf. Struthiosaurus thereby dating back the first occurrence of this genus to the Santonian. The new fossil demonstrates the sympatric co-existence of two different nodosaurid ankylosaurs (a smaller, robust form with 2–2.5 m total body length and a larger, cursorial form with 4–4.5 m body length) in the Iharkút fauna. This also suggests that the pattern of the European ankylosaur diversity was more complex than previously thought. 相似文献
3.
《Cretaceous Research》2012,33(6):774-780
Rebbachisauridae is a poorly understood clade of diplodocoid sauropod dinosaurs, currently known only from the Cretaceous of Africa, Europe and South America. European representatives are particularly rare and fragmentary. Here, we report an anterior caudal vertebra from the Barremian (Early Cretaceous) Wessex Formation of the Isle of Wight, off the southern coast of England. This specimen possesses several features known only in rebbachisaurids and shares two synapomorphies with the Afro-European taxa Demandasaurus darwini and Nigersaurus taqueti, both pertaining to the morphology of the neural spine. These features are the development of triangular lateral processes and the presence of an elliptical fossa on the lateral surface, bounded by the lateral lamina and postspinal rugosity. The Isle of Wight specimen also shares several features solely with Demandasaurus, indicating a close relationship with the Spanish taxon. These include the presence of a hyposphenal ridge, as well as an anteriorly excavated caudal rib that is restricted almost entirely to the neural arch. However, it differs from Demandasaurus in a number of ways, including the lack of excavation on the posterior surface of the caudal rib, the orientation of the neural spine, and the composition and morphology of the lateral lamina. In addition, the Isle of Wight vertebra possesses one potential autapomorphy: bifurcation of the elliptical fossa on the neural spine. However, because of the fragmentary nature of the material, a new name is not erected. Along with Demandasaurus and Histriasaurus boscarollii, this caudal vertebra indicates the presence of at least three European rebbachisaurid taxa and provides new anatomical information on this enigmatic clade of sauropod dinosaurs. 相似文献
4.
Verónica Díez Díaz Géraldine Garcia Fabien Knoll Xabier Pereda Suberbiola Xavier Valentin 《Proceedings of the Geologists' Association. Geologists' Association》2012,123(4):626-637
The Fox-Amphoux Syncline of the Aix Basin (SE France) has yielded a diverse Late Cretaceous vertebrate assemblage, including several taxa of dinosaurs. Here, we report on cranial material of titanosaurian sauropods, which consist of a partial braincase, two fragmentary skull roofs, and nine teeth, from the Métisson locality (Var Department). The braincase differs from those found previously in Europe (i.e., Ampelosaurus atacis, Lirainosaurus astibiae, and an unnamed juvenile skull from Romania) as well as from other titanosaurian braincases in having a groove that extends along the ventral surface of the occipital condyle neck (this feature may be autapomorphic). One of the fragmentary skull roofs may belong to the same taxon, whereas the other suggests the presence of a second titanosaur at Métisson very close to Ampelosaurus. Two dental morphologies are present in the sample; one of them includes teeth of different sizes. We suggest that this could be accounted for by age differences within a single taxon, or be due to different positions in the tooth row. The presence of a new, still unnamed titanosaurian taxon in the Ibero-Armorican Island supports previous works indicating a high titanosaurian diversity during the Campanian-Maastrichtian in southern Europe. 相似文献
5.
A new ornithopod dinosaur from Antarctica, Trinisaura santamartaensis n. gen. et n. sp. is diagnosed by a unique combination of characters that includes a scapula with a spike-like acromial process with a strong and sharp lateral crest and longer than other ornithopods, a humerus with a rudimentary deltopectoral crest represented as a thickening on the anterolateral margin of the humerus, and shaft strongly bowed laterally, and an ischium gently curved along its entire length. The holotype specimen comprises vertebral and appendicular elements. The presence of axially elongate distal caudal vertebrae, pubis with long prepubic and postpubic processes, as well as a femur with a distinct anterior trochanter, pendant 4th trochanter and shallow anterior intercondylar groove constitute a combination of characters present in the Late Cretaceous Patagonian Gasparinisaura, Anabisetia and Talenkahuen. The materials were found on the surface enclosed in a hard sandstone concretion collected near the Santa Marta Cove, James Ross Island, from the lower levels of the Snow Hill Island Formation (Campanian). This is the first ornithopod taxon identified from this unit, and the second ornithischian dinosaur, after the ankylosaur Antarctopelta oliveroi. However, other ornithopod reports from nearby localities of James Ross and Vega islands in outcrops of the overlying Lopez de Bertodano Formation suggest that this clade was widely represented in the Campanian and Maastrichtian of the James Ross Basin, Antarctic continent. 相似文献
6.
WANG Xuri Jingmai K. O’Connor ZHAO Bo Luis M. Chiappe Gao Chunling Cheng Xiaodong 《《地质学报》英文版》2010,84(2):247-256
<正>We report on a new species of enantiornithine bird from the Lower Cretaceous Qiaotou Formation of northern Hebei,China.The new taxon,Shenqiornis mengi gen.et sp.nov.,possesses several enantiornithine synapomorphies but is unique from other known species.The specimen has a well-preserved skull that reveals new information about enantiornithine cranial morphology.The new taxon possesses a large postorbital with a long tapering jugal process indicating that some enantiornithines may have had a fully diapsid skull,as in Confuciusornis.The tooth morphology of the specimen is unique and likely represents a previously unknown trophic specialization within Enantiornithes. 相似文献
7.
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
8.
Rico Stecher 《Swiss Journal of Geoscience》2008,101(1):185-201
A new basal non-pterodactyloid pterosaur, Raeticodactylus filisurensis gen. et sp. nov., is reported. It has been discovered in shallow marine sediments from the Upper Triassic of the lowest Kössen beds (late Norian/early Rhaetian boundary) in the central Austroalpine of Canton Grisons (Switzerland). The disarticulated specimen is comprised of an almost complete skull and a partial postcranial skeleton. A high and thin bony, sagittal cranial crest characterizes the anterodorsal region of the skull. The large mandible, with an additional keel-like expansion at the front, partly matches the enlarged sagittal cranial crest. A direct and close relationship to Austriadactylus cristatus, the only known Triassic pterosaur with a bony cranial crest so far, cannot be established. The teeth of the premaxilla are monocuspid and exhibit very strongly bowed enamel wrinkles on the lingual side whereas the enamel is smooth on the labial side. These monocuspid teeth are large and fang-like. The numerous smaller teeth of the maxilla show three, four and five cusps. These are very similar to the teeth of the Triassic pterosaur Eudimorphodon ranzii. The humerus shows a thinner construction than that seen in other Triassic pterosaurs. The femur is quite unusual with a caput femoris perpendicular to the shaft. The bones of the extremities are almost twice as long as the ones from the largest Triassic specimen E. ranzii (MCSNB 2888). The newly described pterosaur is an adult, with a wingspan of approximately 135 cm. A morphofunctional analysis suggests that R. filisurensis was a highly specialized piscivore and possibly a skim-feeder. 相似文献
9.
Cervical vertebrae of elasmosaurids (Sauropterygia, Plesiosauroidea) have proven to be informative even at family level. The present paper uses a previously developed methodology based on bivariate graphic analysis that evaluates the proportion indices of cervical vertebrae in elasmosaurids, which is applied to a well-preserved postcranial specimen of this group recovered from upper Maastrichtian beds of central Chile. The plotting of such indices groups the Chilean material with other specimens from the Late Cretaceous of Argentina and Antarctica, the latter referred to the genus Aristonectes. This result allows us to identify the first relatively complete individual of the genus based on non-cranial characters. The identification of the Chilean specimen as Aristonectes sp. provides important new data on the postcranial skeleton of the genus, that has remained poorly known until now. 相似文献
10.
New coelacanth material from the Middle Triassic Prosanto Formation of the Ducan and Landwasser area near Davos in eastern Switzerland, Canton Graubünden, is described. A sub-complete individual is visible in ventral view, and shows details of its branchial apparatus. In particular, it possesses relatively large teeth on the ceratobranchials, and possible ossified hypobranchials. Few diagnostic characters are observable, and most of them are visible on the mandibles preserved in lateral view. This specimen shares characters with Ticinepomis peyeri, a smaller form from the Middle Triassic of Monte San Giorgio, whose holotype is re-described in part here. A second specimen, a fragmentary caudal skeleton shows the typical supplementary lobe of coelacanths, and meristic characters indicating probable close affinities with T. peyeri. We refer this material to Ticinepomis cf. T. peyeri. Because the new specimen is larger than the holotype, we refute the possible juvenile status of the small specimen from Monte San Giorgio. The new material of Ticinepomis from Canton Graubünden shows anatomical features not preserved on the holotype and allows the addition of new characters to a previously published data matrix of actinistians. A phylogenetic analysis is performed, which supports that Ticinepomis is nested among the Latimeriidae. The diversity of post-Palaeozoic coelacanths is assessed. The taxic diversity of observed occurrences shows a peak in the Early Triassic and a peak in the Late Jurassic, as detected in previous studies. When ghost lineages are included in the computation, the Late Jurassic peak is smoothened. By comparing the taxic diversity curves with the curve of average ghost lineage duration, we conclude that the Early Triassic peak of diversity was probably caused by a biological radiation, whereas the Late Jurassic peak of observed diversity is probably the result of a Lagerstätten effect. 相似文献
11.
Rupa Ghosh R. K. Sehgal Pradeep Srivastava U. K. Shukla A. C. Nanda D. S. Singh 《Journal of the Geological Society of India》2016,88(5):559-568
We describe an elephant skull recovered from a cliff section of Dhasan river of Marginal Ganga Plain. The dental morphology and cranial features of the skull have been compared with the known species of Elephas from the Indian subcontinent. Although it shows very near resemblance to Elephas namadicus, but being an isolated specimen its specific identity cannot be proclaimed with certainty. As such, the specimen is provisionally referred as E. cf. namadicus. The Optically Stimulated Luminescence ages place this find at ~56 ka BP. This is the first chronologically well constrained report of E. cf. namadicus from the Ganga Plain. 相似文献
12.
Rebbachisauridae is a poorly understood clade of diplodocoid sauropod dinosaurs, currently known only from the Cretaceous of Africa, Europe and South America. European representatives are particularly rare and fragmentary. Here, we report an anterior caudal vertebra from the Barremian (Early Cretaceous) Wessex Formation of the Isle of Wight, off the southern coast of England. This specimen possesses several features known only in rebbachisaurids and shares two synapomorphies with the Afro-European taxa Demandasaurus darwini and Nigersaurus taqueti, both pertaining to the morphology of the neural spine. These features are the development of triangular lateral processes and the presence of an elliptical fossa on the lateral surface, bounded by the lateral lamina and postspinal rugosity. The Isle of Wight specimen also shares several features solely with Demandasaurus, indicating a close relationship with the Spanish taxon. These include the presence of a hyposphenal ridge, as well as an anteriorly excavated caudal rib that is restricted almost entirely to the neural arch. However, it differs from Demandasaurus in a number of ways, including the lack of excavation on the posterior surface of the caudal rib, the orientation of the neural spine, and the composition and morphology of the lateral lamina. In addition, the Isle of Wight vertebra possesses one potential autapomorphy: bifurcation of the elliptical fossa on the neural spine. However, because of the fragmentary nature of the material, a new name is not erected. Along with Demandasaurus and Histriasaurus boscarollii, this caudal vertebra indicates the presence of at least three European rebbachisaurid taxa and provides new anatomical information on this enigmatic clade of sauropod dinosaurs. 相似文献
13.
New theropod remains with abelisaurid affinities from the Upper Cretaceous (Anacleto Formation, lower Campanian), NW Patagonia, Argentina, are here described. The specimen (MPCN-PV 69) consists of a partial premaxilla, fragmentary vertebrae, proximal portion of both humeri, distal portion of the pubis, and an incomplete pedal ungual. Characters linking with Abelisauridae are a premaxilla with a subquadrangular body, externally ornamented, and paradental plates with a striated surface; and humerus with bulbous proximal head, conical internal tuberosity, and reduced greater tubercle. The humerus is similar to those of Carnotaurus and Aucasaurus, due to the presence of a bulbous head and a discontinuity between the head and the internal tuberosity, but also differs from both taxa in the more distal location of the greater tubercle with respect to the internal tuberosity. Aucasaurus also comes from Anacleto Formation, but differences in the humeri suggest that MPCN-PV 69 is a different taxon. The phylogenetic analysis performed supports the affiliation to Abelisauridae, but fails to determinate a more precise relationship with others abelisaurids. However, a majority rule consensus of the analysis shows a position within Brachyrostra. Despite being fragmentary, MPCN-PV 69 probably represents a new abelisaurid from the Anacleto Formation, thus increasing the knowledge and diversity of Late Cretaceous South American abelisaurids. 相似文献
14.
Weishampel David B. Mulder Eric W.A. Dortangs Rudi W. Jagt John W.M. Jianu Coralia-Maria Kuypers Marcel M.M. Peeters Hans H.G. Schulp Anne S. 《Geologie en Mijnbouw》1999,78(3-4):357-365
Isolated cranial and post-cranial remains of hadrosaurid dinosaurs have been collected from various outcrops in the type area of the Maastrichtian stage during the last few years. In the present contribution, dentary and maxillary teeth are recorded from the area for the first time. Post-cranial elements comprise a newly collected, fragmentary, large right metatarsal III and a broken ?right humerus, recently recognised in the collections of Teylers Museum (Haarlem). Unfortunately, none of these remains can be identified to species level. The available material suggests, however, that more than one taxon of non-lambeosaurine hadrosaurid and a possible euhadrosaurian are represented. Most of the new finds are stratigraphically well documented, which means that they may be linked to the recently published sequence-stratigraphic interpretation of the type Maastrichtian. Dinosaur remains recorded previously from the Maastrichtian type area are tabulated.
相似文献15.
The systematics of elasmosaurids are not well resolved partially because of the scarcity of well-preserved skull material. Among Weddellian elasmosaurids, one exception to this is the holotype of Tuarangisaurus keyesi from upper Campanian–lower Maastrichtian levels of the Maungataniwha Sandstone Member of the Tahora Formation, Mangahouanga Stream, inland Hawke's Bay, New Zealand. The material preserves an almost complete cranium and mandible. This material is re-described here, based on new observations and digital reconstruction of the internal anatomy. The result adds one new autapomorphy to the diagnosis of the taxon: ectopterygoid with large boss on the ventral surface and a posteriorly directed process. Additionally new features are recorded: presence of stapes; pterygoid overlapping the vomer, medial sulcus on the dorsal surface of the vomer, parasphenoid–basisphenoid complex covering the ventral surface of the body of the basioccipital. The presence of stapes in Tuarangisaurus keyesi is surprising as they were previously considered absent among elasmosaurids. Phylogenetic analysis indicates a clear elasmosaurid affinity, although there is low resolution within the Elasmosauridae. The previously proposed close relationship with the early Aptian Callawayasaurus colombiensis is rejected. 相似文献
16.
Recent work in the Tropic Shale by the Museum of Northern Arizona reveals a high biodiversity for plesiosaurs along the western margin of the Cretaceous Western Interior Seaway during the Cenomanian and the Turonian. This paper describes a new species of polycotylid plesiosaur from the Tropic Shale, Dolichorhynchops tropicensis, which adds to the known biodiversity from this time period. The identification is based on two specimens, a well-preserved, nearly complete skeleton including the skull and an additional specimen with only fragmentary skeletal elements. The material shares several synapomorphic characters with Dolichorhynchops, including the shape of the temporal fenestrae, the shape of the sagittal crest, the trend of the ectopterygoids, the morphology of the teeth, and the number of teeth within the mandibular symphysis. D. tropicensis differs from other species of Dolichorhynchops in a greater size range of the teeth, moderately constricted dorsal vertebrae, angled anterior processes on the coracoids, and the presence of well-defined facets on the propodials. The specimens are of Early Turonian age (based primarily on ammonite biostratigraphy and bentonite marker beds), and their discovery extends the known stratigraphic range for Dolichorhynchops back by approximately seven million years. This suggests that Dolichorhynchops tropicensis and Trinacromerum bentonianum, a closely related polycotylid, co-existed in the Western Interior Seaway. 相似文献
17.
New Middle Turonian mosasauroid remains were discovered in the same large-sized nodule that yielded a specimen referred to Tethysaurus nopcsai Bardet et al., 2003, from the Goulmima region (southern Morocco). They comprise isolated, fragmentary cranial elements (skull and mandible) and some vertebrae. Their very small size suggests a juvenile condition, an observation supported also by anatomical (spongious nature of numerous bone parts), micro-anatomical (loose inner spongiosa) and histological (numerous remains of calcified cartilage deep into the centrum; radial vascular canals) data. These bones belonged to a basal mosasauroid that cannot be distinguished from Tethysaurus nopcsai to which taxon we tentatively assign the material. 相似文献
18.
This study deals with the biogeography of Antarctic microflora （Antarctica acts as best model to study microbial biogeography） such as cyanobacteria and selected halophiles with special emphasis on Halomonas variabilis and Bacillus licheniformis.Halophiles are known to be resistant not only to salt stress,but also to extreme temperature,pressure,and aridity and they are capable of surviving in harsh environments such as polar regions,deep-sea habitats,and deserts.Many microbes are known to be resistant to hostile environmental conditions,and are capable of surviving in harsh environments.Our group has isolated 444 strains belonging to 28 genera of halophiles from various environments around the world.The 16S rRNA gene sequences revealed that many of the isolated strains from geographically distant habitats having different environmental conditions,were closely related to each other,with some strains possessing 100％ identical sequences.Organisms possessing survival mechanism such as spore formation are usually ubiquitous.The genus Halomonas is represented by potentially endemic strains and the ubiquitous H.variabilis,while spore-forming B.licheniformis showed cosmopolitan distribution.One potentially endemic （moderate endemicity that is regional and/or continental distribution） strain was reported from Syowa station,East Antarctica,and Mario Zucchelli station,West Antarctica,which are geographically separated by 3000 km.Moreover,15 strains having 100％ similarity with B.licheniformis were considered cosmopolitans.The results of this work provide support for the middle-ground model that some microbes have moderate endemicity and others have cosmopolitan distribution.These results will contribute to a greater understanding of microbial biogeography with special emphasis on Antarctica. 相似文献
19.
A Corythosaurus skull (UALVP 13) was collected in 1920 from what is now Dinosaur Provincial Park in southern Alberta, Canada and was designated the holotype of Corythosaurus excavatus, a new hadrosaur species by Gilmore (1923). In 1992, a previously uncovered, weathered, headless skeleton was found. This was collected in 2012 by the University of Alberta as there was potential it could belong to the holotype skull. In addition, an isolated hadrosaur dentary had been found in 1992 close to the articulated postcranial skeleton and may be one of the missing jaws of Corythosaurus excavatus. The hypothesis that it may be the skeleton of the holotype of Corythosaurus excavatus is tested using anatomical information and statistical analyses. Statistical comparisons suggest it is possible that the skull and dentary belong to the same specimen. Furthermore, bivariate plots and percentage prediction errors also indicate that the postcranial material could belong to the UALVP 13 skull. Because many large vertebrate fossil specimens (even types) are not always collected in their entirety, this method may be used as a line of evidence to determine whether independently collected specimens potentially belong to the same individual. The problems described herein highlight the need to collect specimens in their entirety, and for good field documentation, including the spatial and stratigraphic context of all finds. 相似文献
20.
Megaraptoridae comprises a clade of enigmatic Gondwanan theropods with characteristic hypertrophied claws on the first and second manual digits. The majority of megaraptorids are known from South America, although a single genus (Australovenator) plus additional indeterminate material is also known from Australia. This clade has a controversial placement among theropods, and recently has been interpreted alternatively as a carcharodontosaurian or a tyrannosauroid lineage. We describe new fragmentary but associated postcranial remains from the opal fields of Lightning Ridge (middle-Albian, Griman Creek Formation) in north-central New South Wales. The new unnamed taxon exhibits a number of unusual features that suggest the presence of a hitherto unrecognised Australian megaraptorid. From an Australian perspective, the Lightning Ridge taxon predates Australovenator by ca. 10 Ma and is minimally coeval with megaraptoran material reported from the Eumeralla Formation of Victoria (but potentially 6.1–9.5 Ma younger). It is also notable as the largest predatory dinosaur yet identified from Australia and is only the second theropod known from more than a single element. A Bayesian phylogenetic approach integrating morphological, stratigraphic and palaeogeographic information tested both the carcharodontosaurian and tyrannosauroid placements for Megaraptora. Regardless of the preferred placement among Tetanurae, rigorous palaeobiogeographic analyses support an Asian origin of Megaraptora in the latest Jurassic (about 150–135 Ma), an Early Cretaceous (about 130–121 Ma) divergence of the Gondwanan lineage leading to Megaraptoridae, and an Australian root for megaraptorid radiation. These results indicate that Australia's Cretaceous dinosaur fauna did not comprise simply of immigrant taxa but was a source for complex two-way interchange between Australia–Antarctica–South America leading to the evolution of at least one group of apex predatory dinosaurs in Gondwana. 相似文献