A New Eusauropod Dinosaur from the Lower Cretaceous of Guangxi Province, Southern China

<正>A new sauropod dinosaur,Liubangosaurus hei gen.et sp.nov.,is erected based on a specimen represented by five articulated middle-caudal dorsal vertebrae,which was discovered in the Lower Cretaceous Napai Formation of Guangxi Province,southern China.This new taxon is diagnosed by a unique combination of derived features:prezygapophysis closely contacts with parapophysis,with the prdl and prpl absent;presence of cavity on the dorsal surface of the diapophysis;neural spine very low,with its distal end level with that of diapophysis;distal end of the neural spine strongly expanded laterally to form a platform;marked fossa formed between the infradiapophyseal lamina and the parapophysis;broad,flat area of featureless bone on lateral surface of neural arch;vertically directed infradiapophyseal lamina expands or bifurcates ventrally to form a inverted "Y";highly positioned parapophyses large and tear-drop in shape.The discovery of this new taxon increases the diversity of sauropods in China during the Early Cretaceous.     

A new ornithomimid dinosaur from the Upper Cretaceous Packard Shale formation (Cabullona Group) Sonora,México

New ornithomimid material discovered from the Upper Cretaceous Packard Shale Formation, (Cabullona Group) of Sonora, Mexico is described. The material includes a partial skeleton, which is assigned to a new genus and species, Tototlmimus packardensis. This new taxon differs from other ornithomimids in having five unique characteristics that separate it from other Northamerican ornithomimids: (1) a distinctively articulation between metatarsals, where the distal ends of metatarsals II and IV contact directly with the distal facet of metatarsal III; (2) a metatarsal III with a weakly ginglymoid distal articular face; (3) the medial and lateral sides of metatarsal III are shaped into the form of metatarsals II and IV, so all distal ends fit together when they articulate; (4) an asymmetrical and narrow pedal ungual with shallow grooves in both medial and lateral sides; and finally, (5) the presence of a deep sulcus on the ventromedial edge, close to the articular end. Phylogenetic analysis suggests that Tototlmimus packardensis corresponds to a derived ornithomimid included in the Northamerican clade, forming a monophyly with Ornithomimus. Tototlmimus packardensis is the first definitive ornithomimid described for Mexico, and represents one of the southernmost occurrences in the Western Interior Basin of North America.     

New rebbachisaurid (Dinosauria: Sauropoda) material from the Wessex Formation (Barremian,Early Cretaceous), Isle of Wight,United Kingdom

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.     

Small-sized abelisaurid (Theropoda: Ceratosauria) remains from the Upper Cretaceous of northwest Patagonia,Argentina

A new abelisaurid theropod from the Cenomanian of Candeleros Formation (Neuquén Province, NW Patagonia, Argentina) is described. It includes an isolated frontal, partial pelvis, two fused sacral centra, femoral shaft, rib fragments, partial metatarsal II and shaft of metatarsal III. A paleohistological analysis shows that MMCh-PV 69 was somatically mature at time of death. The prevalence of relatively ordered intrinsic fibers in the primary bone indicates a relatively lower growth rate of MMCh-PV 69 compared with other abelisauroids, such as Aucasaurus garridoi. Phylogenetic analysis found MMCh-PV 69 as a basal abelisaurid, sister group of the node formed by Majungasaurinae and Brachyrostra. We estimated the body mass of MMCh-PV 69 in 240 kg, which makes it one of the smallest abelisaurids recorded. This new form adds to the extensive theropod fauna of the Candeleros Formation, probably the most diverse association of meat-eating dinosaurs recorded in a Cretaceous Formation from South America.     

New Material of Pterosaur Sinopterus （Reptilia： Pterosauria） from the Early Cretaceous Jiufotang Formation, Western Liaoning, China

1 Introduction The Jiufotang Formation is one of the most fossil- productive Early Cretaceous deposits of China. It overlies the famous Yixian Formation from which many important taxa were found (Ji et al., 2004; Chang et al., 2003; Zhou et al., 2003). In addition to other vertebrates, pterosaurs, the first flying reptiles in Earth history, are also abundant in the Jiufotang Formation. At present, nine species belonging to five genera have been reported from the Jiufotang Formation. The…     

Postcranial Anatomy of the Mesozoic Dalinghosaurus (Squamata): Evidence from a New Specimen of Western Liaoning

The postcranial skeleton of a new specimen of the long-tailed lizard Dalinghosaurus longidigitus was excavated from the Yixian Formation in Lingyuan, western Liaoning. The new specimen provides more anatomical information about this species, especially about the anterior dorsal vertebrae, shoulder girdle and forelimbs. This lizard can be included within the clade Scleroglossa by its 27 or more presacrals, moderately long pubis, and gently notched distal end of tibia. But the detailed systematic position for this taxon remains undetermined. The features of the much longer hind limbs and pes compared with forelimbs and manus, metatarsal Ⅳ longer than Ⅲ, pedal phalanges robust, and penultimate phalanx not longer than other phalanges etc. suggest that this lizard was a running and ground swelling animal.     

Anurans from the Candeleros Formation (?Cenomanian-Turonian) of west-central Argentina: new evidence for pipoid evolution

The fluvio-lacustrine deposits of the ?Cenomanian-Turonian Candeleros Formation in the northwestern fringe of Patagonia have yielded numerous remains of vertebrates, including anurans. A new, partially articulated immature specimen of a small pipimorph pipoid from the upper part of this unit is described herein. Although incompletely preserved, the morphology and proportions of the skeleton are strongly reminiscent of corresponding elements of the holotype of Avitabatrachus uliana from the lower section of the same formation at a nearby locality, thus suggesting that these specimens might represent the same, or a closely related, taxon. The new specimen is a metamorphosing individual: it has a zygapophyseal articulation between the sacrum and the neural arch of a postsacral vertebra that bears conspicuous transverse processes, and four pairs of ribs. These traits are not present in the available material of A. uliana, but they might have occurred within the normal range of variation of a single species. Although the generic and specific allocation of the new material is uncertain, a parsimony analysis performed to clarify the relationships of A. uliana supports a phylogenetic placement of this taxon outside the crown Pipidae. The evidence provided by the Candeleros anurans confirms the presence of stem pipids in Patagonia in the early Late Cretaceous.     

First occurrence of a tyrannosaurid dinosaur from the Mesaverde Group (Neslen Formation) of Utah: Implications for upper Campanian Laramidian biogeography

Although upper Campanian dinosaur assemblages are well-known from Alberta, Montana, southern Utah, and New Mexico, specimens from Wyoming and central and eastern Utah are very rare. This area constitutes a biogeographic break between northern and southern biogeographic provinces, so any specimens from this region are critical to understanding the origin, evolution, and limits of upper Campanian biogeographic zones on the west margin of the Western Interior Seaway. We report the discovery of a theropod dinosaur partial hindlimb from the Book Cliffs area northeast of Green River, Utah. The specimen was recovered from the Palisade coal zone in the Neslen Formation (Mesaverde Group), which is dated to the mid-Campanian based on ammonite biostratigraphy and radioisotopic age constraints. The specimen, comprising a partial fibula, the distal half of metatarsal II, a complete metatarsal IV, and a partial metatarsal V, can be assigned to Tyrannosauridae based on a number of synapomorphies, including a bipartite iliofibularis tubercle on the fibula and a teardrop shaped articular surface for metatarsal III on the medial surface of the distal portion of metatarsal IV. This is the first unambiguous tyrannosaurid dinosaur reported from the Mesaverde Group and represents an important biogeographic record situated between northern and southern upper Campanian vertebrate assemblages. Specifically, we identify morphological evidence on the pes that separates northern (Montana and Alberta) and southern (southern Utah and New Mexico) tyrannosaurid dinosaurs, and suggests that the Book Cliffs specimen belongs to the northern group. This implies that either the biogeographic boundary between the northern and southern Campanian assemblages lies somewhere between central and southern Utah or that the Book Cliffs taxon represents a northern emigrant in the southern assemblage.     

New rebbachisaurid (Dinosauria: Sauropoda) material from the Wessex Formation (Barremian, Early Cretaceous), Isle of Wight, United Kingdom

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.     

An unusual modification of the jaws in cf. Alanqa,a mid-Cretaceous azhdarchid pterosaur from the Kem Kem beds of Morocco

A jaw bone attributed to the mid-Cretaceous azhdarchid pterosaur Alanqa saharica Ibrahim et al., 2010 is described. The new specimen from the Kem Kem beds of south eastern Morocco is unusual for the presence of expanded rostral bones that protrude above the occlusal surface of the jaws. The function of this unusual osteological modification is uncertain, but it is considered likely that it served a role in food processing, or perhaps jaw stability.     

A densely feathered ornithomimid (Dinosauria: Theropoda) from the Upper Cretaceous Dinosaur Park Formation,Alberta, Canada

A recently discovered articulated partial skeleton of Ornithomimus from the Upper Cretaceous Dinosaur Park Formation of Alberta, Canada is remarkable in the extent and quality of preservation of integumentary structures including feathers. It is the first ornithomimid to preserve a tail bearing extensive plumaceous feathers that are slightly more elongate in comparison to those present on the remainder of the body. However, the underside of the tail and the hind limb distal to the middle of the femur appear devoid of plumage. Overall, the plumage pattern in Ornithomimus is similar to that of Struthio camelus (ostrich) and other large palaeognaths, indicating a probable function in thermoregulation. The specimen also preserves the body outline around the legs, including a skin contour anterior to the femur, analogous to skin webs in extant birds. Whereas the knee web of birds bridges the knee to the abdomen, in Ornithomimus it spans from the mid-femoral shaft to the abdomen, and is herein referred to as an anterior femoral web. This is the first report of such soft tissue structures in non-avian theropods. It may indicate that the resting position of the femur was positioned more anteroventrally in ornithomimids than in most theropods, and in that sense may have been transitional to the situation in modern birds.     

Ornithomimidae (Dinosauria: Theropoda) from the Bissekty Formation (Upper Cretaceous: Turonian) of Uzbekistan

The stratigraphically oldest remains of ornithomimid theropod dinosaurs are known from the Cenomanian Khodzhakul Formation and the Turonian Bissekty Formation of Uzbekistan. The ornithomimid from the Bissekty Formation is documented by more than 800 isolated bones that represent much of the skeleton. It shows at least three unambiguous synapomorphies of Ornithomimidae: length of anterior cervical centra three to five times greater than transverse width; low and rounded fibular crest of tibia; metatarsal III pinched between metatarsals II and IV; and proximal end of metatarsal III not visible in anterior view. Phylogenetic analysis, based on a dataset with 568 morphological characters and including all known ornithomimosaurian taxa, places the ornithomimid from the Bissekty Formation near the base of the ornithomimid radiation, between Archaeornithomimus asiaticus and Sinornithomimus dongi.     

A Basal Titanosauriform from the Early Cretaceous of Guangxi, China

Based on a partial postcranial skeleton collected from the Lower Cretaceous Napai Formation of Guangxi, China, we erect a new sauropod taxon, Fusuisaurus zhaoi gen. et sp. nov. The holotype specimen consists of the left ilium, left pubis, anterior caudals, most of the dorsal ribs and distal end of the left femur. Fusuisaurus zhaoi is diagnosed by a unique combination of character states among the known sauropods. It displays several synapomorphies of Titanosauriformes but lacks many derived features seen in other titanosauriforms, suggesting that the new taxon represents the basalmost known titanosauriform and providing new evidence that Titanosauriformes originated from Asia. A size comparison suggests that Fusuisaurus zhaoi is among the largest Early Cretaceous sauropods, providing an important addition to the Early Cretaceous Chinese sauropod diversity.     

New material of the large-bodied caenagnathid Caenagnathus collinsi from the Dinosaur Park Formation of Alberta,Canada

A reexamination of large caenagnathid material from the Upper Cretaceous (Campanian) Dinosaur Park Formation of Alberta, Canada, reveals undescribed material referable to Caenagnathus collinsi. A femur, two astragalocalcanei, two metatarsals, two unguals, and a caudal vertebra provide anatomical information on Caenagnathus collinsi. Estimates of femoral length based on the proportions of other oviraptorids suggest that the non-femoral material represents a taxon intermediate in size between Chirostenotes pergracilis from the Dinosaur Park Formation and Anzu wyliei from the Maastrichtian Hell Creek Formation. The femur is within the range of predictions, and confirms the body size estimates based on the other material. The large size of the material and a number of morphological characters distinguish the material from Chirostenotes pergracilis and suggest that it is referable to Caenagnathus collinsi. The relative diversity of caenagnathids in the Dinosaur Park Formation is likely underestimated.     

First Lower Cretaceous record of Podocarpaceae wood associated with dinosaur remains from Patagonia,Neuquén Province,Argentina

The first Podocarpaceae wood record is described from the Mulichinco Formation (Valanginian, Lower Cretaceous), Neuquén Basin, Argentina. The specimen was directly associated with a middle caudal vertebra of a diplodocid sauropod dinosaur. A new species – Podocarpoxylon prumnopityoides – is proposed based on features that include the presence of abietinean wood type (tracheid radial pitting), plus podocarpoid (cupressoid type) and some dacrydioid (taxodioid type) cross-field pits, diffuse axial parenchyma and low rays. This combination of anatomical characters is comparable to both Prumnopitys and Podocarpus, whereas the type of pits in the cross-fields resembles some members of the extant Prumnopitys. This is the first unequivocal record of the Family Podocarpaceae in the Valanginian of South America and confirms the hypothesis that the divergence between the “Podocarpoid-Dacrydioid” and “Prumnopityoid” clades occurred earlier than the Early Cretaceous.     

A saltasaurine titanosaur (Sauropoda: Titanosauriformes) from the Angostura Colorada Formation (upper Campanian,Cretaceous) of northwestern Patagonia,Argentina

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.     

A possible azhdarchid pterosaur (Pterosauria,Azhdarchidae) in the Durlston Formation (Early Cretaceous,Berriasian) of southern England

A new specimen of pterosaurian metacarpal IV from the Early Cretaceous (Berriasian) Durlston Formation of Dorset, southern England, closely resembles those of the Chinese dsungaripterid Dsungaripterus weii Young, 1964 and the Central Asian azhdarchid Azhdarcho lancicollis Nessov, 1984. However, the new specimen lacks the thickened bony wall typical of Dsungaripteridae and is therefore regarded as azhdarchoid. An mcIV with a markedly offset distal condyle with well-developed diaphyseal constriction behind the distal condyle and asymmetrical condylar margins may be an autapomorphy of Dsungaripteridae + Azhdarchoidea, while the same condition with bone thickening may typify Dsungaripteridae. The new specimen also provides osteological evidence supporting claims for large wing-spanned pterosaurs in the Berriasian of southern England based previously only on ichnological finds. The new specimen suggests a wingspan of between 2.9 and 3.7 m and represents the largest pterosaur from the Berriasian.     

New evidence for the possible occurrence of Tyrannosaurus in West Texas,and discussion of Maastrichtian tyrannosaurid dinosaurs from Big Bend National Park

Speculation regarding Tyrannosaurus in West Texas has been largely based upon a sub-adult tyrannosaurid maxilla from the Javelina Formation (Late Cretaceous–Maastrichtian) of Big Bend National Park. However, a very large anterior caudal vertebra, recently collected from the Javelina Formation, exhibits a morphology that can confidently be assigned to Tyrannosauridae and, because of its size, likely pertains to an adult Tyrannosaurus. The stratigraphic position of the specimen is closely bracketed by titanosaurid remains and further supports coexistence of these taxa. The stratigraphic position of the specimen possibly records one of the earliest occurrences of Tyrannosaurus. If so, Tyrannosaurus likely existed during roughly equivalent temporal intervals in disparate paleobiomes in both northern and southern late Maastrichtian faunal realms of North America.