A New Sauropod Dinosaur from the Middle Jurassic of the United Kingdom

A new record of a sauropodomorph dinosaur is here described from the Middle Jurassic (Aalenian) Saltwick Formation of Whitby (Yorkshire), UK. A single caudal vertebra represents an early sauropodomorph and signifies the earliest recognised eusauropod dinosaur from the United Kingdom. The absence of pleurocoels and a narrow, dorsoventrally deep, but craniocaudally short centrum, suggests a primitive sauropodomorph. Distinct spinopostzygopophyseal laminae rise from the lateral margins of the postzygapophyses and pass caudally along what remains of the neural spine, a character unique to a subgroup of sauropods that includes Barapasaurus, Omeisaurus and other neosauropods and eusauropods. The lack of phylogenetically robust characters in sauropod caudal vertebrae usually makes it difficult to establish affinities, but the absence of mild procoely excludes this specimen from both Diplodocoidea and Lithostrotia. The vertebra cannot be further distinguished from those of a wide range of basal sauropods, cetiosaurids and basal macronarians. However, this plesiomorphic vertebra still signifies the earliest stratigraphic occurrence for a British sauropod dinosaur.     

A New Basal Sauropodomorph Dinosaur from the Lower Jurassic Navajo Sandstone of Southern Utah

Background

Basal sauropodomorphs, or ‘prosauropods,’ are a globally widespread paraphyletic assemblage of terrestrial herbivorous dinosaurs from the Late Triassic and Early Jurassic. In contrast to several other landmasses, the North American record of sauropodomorphs during this time interval remains sparse, limited to Early Jurassic occurrences of a single well-known taxon from eastern North America and several fragmentary specimens from western North America.

Methodology/Principal Findings

On the basis of a partial skeleton, we describe here a new basal sauropodomorph dinosaur from the Lower Jurassic Navajo Sandstone of southern Utah, Seitaad ruessi gen. et sp. nov. The partially articulated skeleton of Seitaad was likely buried post-mortem in the base of a collapsed dune foreset. The new taxon is characterized by a plate-like medial process of the scapula, a prominent proximal expansion of the deltopectoral crest of the humerus, a strongly inclined distal articular surface of the radius, and a proximally and laterally hypertrophied proximal metacarpal I.

Conclusions/Significance

Phylogenetic analysis recovers Seitaad as a derived basal sauropodomorph closely related to plateosaurid or massospondylid ‘prosauropods’ and its presence in western North America is not unexpected for a member of this highly cosmopolitan clade. This occurrence represents one of the most complete vertebrate body fossil specimens yet recovered from the Navajo Sandstone and one of the few basal sauropodomorph taxa currently known from North America.     

A New Taxon of Basal Ceratopsian from China and the Early Evolution of Ceratopsia

Ceratopsia is one of the best studied herbivorous ornithischian clades, but the early evolution of Ceratopsia, including the placement of Psittacosaurus, is still controversial and unclear. Here, we report a second basal ceratopsian, Hualianceratops wucaiwanensis gen. et sp. nov., from the Upper Jurassic (Oxfordian) Shishugou Formation of the Junggar Basin, northwestern China. This new taxon is characterized by a prominent caudodorsal process on the subtemporal ramus of the jugal, a robust quadrate with an expansive quadratojugal facet, a prominent notch near the ventral region of the quadrate, a deep and short dentary, and strongly rugose texturing on the lateral surface of the dentary. Hualianceratops shares several derived characters with both Psittacosaurus and the basal ceratopsians Yinlong, Chaoyangsaurus, and Xuanhuaceratops. A new comprehensive phylogeny of ceratopsians weakly supports both Yinlong and Hualianceratops as chaoyangsaurids (along with Chaoyangsaurus and Xuanhuaceratops), as well as the monophyly of Chaoyangosauridae + Psittacosaurus. This analysis also weakly supports the novel hypothesis that Chaoyangsauridae + Psittacosaurus is the sister group to the rest of Neoceratopsia, suggesting a basal split between these clades before the Late Jurassic. This phylogeny and the earliest Late Jurassic age of Yinlong and Hualianceratops imply that at least five ceratopsian lineages (Yinlong, Hualianceratops, Chaoyangsaurus + Xuanhuaceratops, Psittacosaurus, Neoceratopsia) were present at the beginning of the Late Jurassic.     

Hettangian (Early Jurassic) Dinosaur Tracksites from the Mecsek Mountains,Hungary

A rare example of a North American Jurassic hardground is found in the Carmel Formation of southwestern Utah. The Carmel hard‐ground was formed across a carbonate lagoon from an oolitic shoal seaward to a subtidal shelly facies landward. It has an abundant bivalve fauna consisting of thick layers of encrusters (the oyster Liostrea and the plicatulid Plicatula), borers (the ichnofossil Gastro‐chaenolites with the mytilid Lithophaga often preserved inside), and nestlers (the mytilid Modiolus). A rare soft‐bodied bryozoan (Arach‐nidium) is preserved by bioimmuration in the attachment scars of Liostrea; this is the first bioimmuration recorded from the Jurassic of North America, and the first bioimmuration recorded from a hard‐ground. The phoronid boring Talpina is present in some Liostrea shells; it was apparently excavated after the death of these oysters. The Carmel hardground community does not contain other fossils, such as serpulids, brachiopods, foraminiferans, and skeletal bryo‐zoans, typical of Jurassic hardgrounds elsewhere. It represents a low diversity molluscan community developed in a restricted marine environment.     

A Giant Dinosaur from the Earliest Jurassic of South Africa and the Transition to Quadrupedality in Early Sauropodomorphs

1. Download high-res image (220KB)
2. Download full-size image

     

A Sauropod Dinosaur tooth from the Lower Cretaceousof Galve (Province of Teruel,Spain)

A sauropod tooth, from the Barremian-Aptian ofGalve (Teruel), is described in Spain for the first time. This tooth probably belongs to the sauropod reported by A.F. de Lapparent (1), a Brachiosaurinae different of that reported by J.V. Santafé, M.L. Casanovas & J.L. Sanz (2) and J.L. Sanz, J.V. Santafé & M.L. Casanovas (3) from Morella (Castellón, Spain), Lower Aptian in age. It is probably a lower left piece with a developped worn surface. The subfamily Brachiosaurinae-sensuR. Steel, 1970 (4)-has a certain coherence of tooth morphology in respect of other Camarasauridae-sensuR. Steel, 1970 (4). The piece from Galve belongs to a Brachiosaurinae close to Brachiosaurus, though could differ of this genus in the structure and distribution of enamel ornamentation.     

Middle and Late Jurassic terebratulides from New Zealand

Terebratulide brachiopods are found throughout the New Zealand Mesozoic, and by the Jurassic are second only to rhynchonellides in abundance and diversity. Only two species have been described from the Late Jurassic, Kutchithyris hendersoni Marwick, 1953 and Holcothyris (?) kaiwaraensis Campbell, 1965. In this study, one new genus and 14 new species are described, and three additional forms placed in open nomenclature.Nearly all the material comes from the Murihiku Terrane on the west coast of the North Island south of Auckland, and most from a small number of shellbeds with diverse faunas. Two key localities for Middle Jurassic (Bajocian–Bathonian) brachiopods are Opuatia Cliff at Port Waikato, and a quarry in the Marokopa Valley. Two species of fairly large terebratulide, Loboidothyris waitomoensis n. sp. and L. grantmackiei n. sp. are tentatively assigned to the genus Loboidothyris. A further species which may also belong to this genus, L. awakinoensis n. sp. is found in the Awakino Valley to the south. Two species of Zeilleria, Z. opuatiaensis n. sp. and Z. waiohipaensis n. sp. and one of Aulacothyris, A. waikatoensis n. sp. are also recognised. A new species of Kutchithyris, K. marokopaensis n. sp., less strongly folded than K. hendersoni, is also present.Captain King's Shellbed is a metre-thick Oxfordian shellbed that can be traced from Kawhia to the Awakino Valley. It has a rich and diverse fauna in which terebratulides are prominent. Kutchithyris hendersoni is the most abundant, followed by Crispithyris nauarchus n. gen. n. sp. The fauna also includes the same two species of Zeilleria as in the Middle Jurassic, and the costellate terebratulide Terebratulina leeae n. sp.Brachiopods are much less common in the later part of the Jurassic (Kimmeridgian and Tithonian). A further species of Kutchithyris, K. challinori n. sp., a second species of Terebratulina, T. putiensis n. sp. and one of Zeilleria (Z. sp.) are present. A rare form is the small subcircular Disculina mancenidoi n. sp. Holcothyris kaiwaraensis is known only from the Late Jurassic Pahau Terrane of North Canterbury, but a second species of Holcothyris, H. campbelli n. sp. is present in the Late Oxfordian and Kimmeridgian of the Kawhia area.Aulacothyris, Terebratulina, and Zeilleria are cosmopolitan. Kutchithyris and Holcothyris are Tethyan. Loboidothyris is more widely distributed but generally Tethyan. Disculina is described from Southern England and France, but has since been recognised in the Caucasus and Japan, and may also have a Tethyan distribution.     

A New Hadrosauroid Dinosaur from the Early Late Cretaceous of Shanxi Province,China

Background

The origin of hadrosaurid dinosaurs is far from clear, mainly due to the paucity of their early Late Cretaceous close relatives. Compared to numerous Early Cretaceous basal hadrosauroids, which are mainly from Eastern Asia, only six early Late Cretaceous (pre-Campanian) basal hadrosauroids have been found: three from Asia and three from North America.

Methodology/Principal Findings

Here we describe a new hadrosauroid dinosaur, Yunganglong datongensis gen. et sp. nov., from the early Late Cretaceous Zhumapu Formation of Shanxi Province in northern China. The new taxon is represented by an associated but disarticulated partial adult skeleton including the caudodorsal part of the skull. Cladistic analysis and comparative studies show that Yunganglong represents one of the most basal Late Cretaceous hadrosauroids and is diagnosed by a unique combination of features in its skull and femur.

Conclusions/Significance

The discovery of Yunganglong adds another record of basal Hadrosauroidea in the early Late Cretaceous, and helps to elucidate the origin and evolution of Hadrosauridae.     

A Diplodocid Sauropod Survivor from the Early Cretaceous of South America

Diplodocids are by far the most emblematic sauropod dinosaurs. They are part of Diplodocoidea, a vast clade whose other members are well-known from Jurassic and Cretaceous strata in Africa, Europe, North and South America. However, Diplodocids were never certainly recognized from the Cretaceous or in any other southern land mass besides Africa. Here we report a new sauropod, Leikupal laticauda gen. et sp. nov., from the early Lower Cretaceous (Bajada Colorada Formation) of Neuquén Province, Patagonia, Argentina. This taxon differs from any other sauropod by the presence of anterior caudal transverse process extremely developed with lateroventral expansions reinforced by robust dorsal and ventral bars, very robust centroprezygapophyseal lamina in anterior caudal vertebra and paired pneumatic fossae on the postzygapophyses in anterior-most caudal vertebra. The phylogenetic analyses support its position not only within Diplodocidae but also as a member of Diplodocinae, clustering together with the African form Tornieria, pushing the origin of Diplodocoidea to the Middle Jurassic or even earlier. The new discovery represents the first record of a diplodocid for South America and the stratigraphically youngest record of this clade anywhere.     

A Basal Lithostrotian Titanosaur (Dinosauria: Sauropoda) with a Complete Skull: Implications for the Evolution and Paleobiology of Titanosauria

We describe Sarmientosaurus musacchioi gen. et sp. nov., a titanosaurian sauropod dinosaur from the Upper Cretaceous (Cenomanian—Turonian) Lower Member of the Bajo Barreal Formation of southern Chubut Province in central Patagonia, Argentina. The holotypic and only known specimen consists of an articulated, virtually complete skull and part of the cranial and middle cervical series. Sarmientosaurus exhibits the following distinctive features that we interpret as autapomorphies: (1) maximum diameter of orbit nearly 40% rostrocaudal length of cranium; (2) complex maxilla—lacrimal articulation, in which the lacrimal clasps the ascending ramus of the maxilla; (3) medial edge of caudal sector of maxillary ascending ramus bordering bony nasal aperture with low but distinct ridge; (4) ‘tongue-like’ ventral process of quadratojugal that overlaps quadrate caudally; (5) separate foramina for all three branches of the trigeminal nerve; (6) absence of median venous canal connecting infundibular region to ventral part of brainstem; (7) subvertical premaxillary, procumbent maxillary, and recumbent dentary teeth; (8) cervical vertebrae with ‘strut-like’ centroprezygapophyseal laminae; (9) extremely elongate and slender ossified tendon positioned ventrolateral to cervical vertebrae and ribs. The cranial endocast of Sarmientosaurus preserves some of the most complete information obtained to date regarding the brain and sensory systems of sauropods. Phylogenetic analysis recovers the new taxon as a basal member of Lithostrotia, as the most plesiomorphic titanosaurian to be preserved with a complete skull. Sarmientosaurus provides a wealth of new cranial evidence that reaffirms the close relationship of titanosaurs to Brachiosauridae. Moreover, the presence of the relatively derived lithostrotian Tapuiasaurus in Aptian deposits indicates that the new Patagonian genus represents a ‘ghost lineage’ with a comparatively plesiomorphic craniodental form, the evolutionary history of which is missing for at least 13 million years of the Cretaceous. The skull anatomy of Sarmientosaurus suggests that multiple titanosaurian species with dissimilar cranial structures coexisted in the early Late Cretaceous of southern South America. Furthermore, the new taxon possesses a number of distinctive morphologies—such as the ossified cervical tendon, extremely pneumatized cervical vertebrae, and a habitually downward-facing snout—that have rarely, if ever, been documented in other titanosaurs, thus broadening our understanding of the anatomical diversity of this remarkable sauropod clade. The latter two features were convergently acquired by at least one penecontemporaneous diplodocoid, and may represent mutual specializations for consuming low-growing vegetation.     

陕西子洲中侏罗世早期恐龙足迹初步研究

陕西子洲县中侏罗统延安组砂岩中,同一地点共厚约1.7 m的5个层面发现4种食肉类恐龙足迹,自上而下分别为:1)第5层面大型三趾型足迹,实雷龙足迹科王氏子洲足迹(新遗迹属、新遗迹种)Zizhoupus wangi ichnogen.et ichnosp,nov.;2)第4和第3层面中型三趾型足迹,实雷龙足迹科龙尾峁张北足迹(新遗迹种)Changpeipus longweimaoensis inchnosp.nov.;3)第2层面小型三趾或四趾型足迹,虚骨龙类小理河陕西足迹(新遗迹种)Shensipus xiaoliheensis inchnosp.nov.;4)第1层面小型三趾型足迹,虚骨龙类的铜川陕西足迹Shensipus tungchuanensis.     

陕西子洲中侏罗世早期恐龙足迹初步研究（英文）

陕西子洲县中侏罗统延安组砂岩中,同一地点共厚约1.7 m的5个层面发现4种食肉类恐龙足迹,自上而下分别为:1)第5层面大型三趾型足迹,实雷龙足迹科王氏子洲足迹(新遗迹属、新遗迹种)Zizhoupus wangi ichnogen.et ichnosp.nov.;2)第4和第3层面中型三趾型足迹,实雷龙足迹科龙尾峁张北足迹(新遗迹种)Changpeipus longweimaoensis inchnosp.nov.;3)第2层面小型三趾或四趾型足迹,虚骨龙类小理河陕西足迹(新遗迹种)Shensipus xiaoliheensis inchnosp.nov.;4)第1层面小型三趾型足迹,虚骨龙类的铜川陕西足迹Shensipus tungchuanensis。     

Extramorphological Features of Sauropod Dinosaur Tracks in the Uhangri Formation (Cretaceous), Korea

Sauropod footprints in the Uhangri Formation (Cretaceous) of Korea exhibit an unusual pattern of morphology, with the interior of each print partitioned into a series of pockets by conspicuous radial crests. The crests are evidently extramorphological features and have been interpreted as upwellings of sediment extruded through the floor of the footprint following its fracture by impact of the trackmaker's foot. That explanation entails some inconsistencies, and an alternative explanation is proposed here. The alternative explanation envisages delamination of a superficial sheet of sediment that was lifted into a canopy, which subsequently collapsed in radiating folds. The superficial sheet of sediment might have been lifted by either or both of two mechanisms—by adhering to the underside of the trackmaker's foot or by being forced upward into a blister-like dome by the backflow of water previously displaced by impact of the trackmaker's foot. These alternative explanations draw attention to minor morphological features that were previously unexplained.     

Bird-Like Anatomy,Posture, and Behavior Revealed by an Early Jurassic Theropod Dinosaur Resting Trace

Background

Fossil tracks made by non-avian theropod dinosaurs commonly reflect the habitual bipedal stance retained in living birds. Only rarely-captured behaviors, such as crouching, might create impressions made by the hands. Such tracks provide valuable information concerning the often poorly understood functional morphology of the early theropod forelimb.

Methodology/Principal Findings

Here we describe a well-preserved theropod trackway in a Lower Jurassic (∼198 million-year-old) lacustrine beach sandstone in the Whitmore Point Member of the Moenave Formation in southwestern Utah. The trackway consists of prints of typical morphology, intermittent tail drags and, unusually, traces made by the animal resting on the substrate in a posture very similar to modern birds. The resting trace includes symmetrical pes impressions and well-defined impressions made by both hands, the tail, and the ischial callosity.

Conclusions/Significance

The manus impressions corroborate that early theropods, like later birds, held their palms facing medially, in contrast to manus prints previously attributed to theropods that have forward-pointing digits. Both the symmetrical resting posture and the medially-facing palms therefore evolved by the Early Jurassic, much earlier in the theropod lineage than previously recognized, and may characterize all theropods.