Predation upon Hatchling Dinosaurs by a New Snake from the Late Cretaceous of India

A new snake from Upper Cretaceous rocks in India is found with hatchling sauropod dinosaurs, demonstrating that large, gape-limited snakes were probably capable of taking in moderate-sized vertebrate prey

A Nomenclature for Vertebral Fossae in Sauropods and Other Saurischian Dinosaurs

The axial skeleton of extinct saurischian dinosaurs (i.e., theropods, sauropodomorphs), like living birds, was pneumatized by epithelial outpocketings of the respiratory system. Pneumatic signatures in the vertebral column of fossil saurischians include complex branching chambers within the bone (internal pneumaticity) and large chambers visible externally that are bounded by neural arch laminae (external pneumaticity). Although general aspects of internal pneumaticity are synapomorphic for saurischian subgroups, the individual internal pneumatic spaces cannot be homologized across species or even along the vertebral column, due to their variability and absence of topographical landmarks. External pneumatic structures, in contrast, are defined by ready topological landmarks (vertebral laminae), but no consistent nomenclatural system exists. This deficiency has fostered confusion and limited their use as character data in phylogenetic analysis.We present a simple system for naming external neural arch fossae that parallels the one developed for the vertebral laminae that bound them. The nomenclatural system identifies fossae by pointing to reference landmarks (e.g., neural spine, centrum, costal articulations, zygapophyses). We standardize the naming process by creating tripartite names from “primary landmarks,” which form the zygodiapophyseal table, “secondary landmarks,” which orient with respect to that table, and “tertiary landmarks,” which further delineate a given fossa.The proposed nomenclatural system for lamina-bounded fossae adds clarity to descriptions of complex vertebrae and allows these structures to be sourced as character data for phylogenetic analyses. These anatomical terms denote potentially homologous pneumatic structures within Saurischia, but they could be applied to any vertebrate with vertebral laminae that enclose spaces, regardless of their developmental origin or phylogenetic distribution

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.Fil: Martínez, Rubén Darío. Universidad Nacional de la Patagonia; ArgentinaFil: Lamanna, Matthew C.. Carnegie Museum Of Natural History; Estados UnidosFil: Novas, Fernando Emilio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "bernardino Rivadavia"; ArgentinaFil: Ridgely, Ryan C.. Ohio University College Of Osteopathic Medicine; Estados UnidosFil: Casal, Gabriel. Universidad Nacional de la Patagonia; ArgentinaFil: Martínez, Javier E.. Hospital Regional de Comodoro Rivadavia; ArgentinaFil: Vita, Javier R.. Resonancia Magnética Borelli; ArgentinaFil: Witmer, Lawrence M.. Ohio University College Of Osteopathic Medicine; Estados Unido

Paleobiology of titanosaurs: reproduction, development, histology, pneumaticity, locomotion and neuroanatomy from the South American fossil record

Fil: García, Rodolfo A.. Instituto de Investigación en Paleobiología y Geología. Museo Provincial Carlos Ameghino. Cipolletti; ArgentinaFil: Salgado, Leonardo. Instituto de Investigación en Paleobiología y Geología. General Roca. Río Negro; ArgentinaFil: Fernández, Mariela. Inibioma-Centro Regional Universitario Bariloche. Bariloche. Río Negro; ArgentinaFil: Cerda, Ignacio A.. Instituto de Investigación en Paleobiología y Geología. Museo Provincial Carlos Ameghino. Cipolletti; ArgentinaFil: Carabajal, Ariana Paulina. Museo Carmen Funes. Plaza Huincul. Neuquén; ArgentinaFil: Otero, Alejandro. Museo de La Plata. Universidad Nacional de La Plata; ArgentinaFil: Coria, Rodolfo A.. Instituto de Paleobiología y Geología. Universidad Nacional de Río Negro. Neuquén; ArgentinaFil: Fiorelli, Lucas E.. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica. Anillaco. La Rioja; Argentin

Correction: Evolution of high tooth replacement rates in theropod dinosaurs.

[This corrects the article DOI: 10.1371/journal.pone.0224734.]

Flowchart explaining the construction of simple bipartite and tripartite names for fossae on neural arches.

<p>These decision trees show how to name fossae. Rounded rectangles are starting/stopping points, and diamonds represent decisions. Starting from the upper left, primary, secondary, and tertiary landmarks are identified in succession. The majority of landmark-bounded fossae can be identified by one of the tripartite names created by combining one of three primary landmarks (diapophysis, prezygapophysis, postzygapophysis), one of two secondary landmarks (neural spine, centrum), and one of three tertiary landmarks (parapophysis, prezygapophysis, postzygapophysis). The resultant named fossae recognized here are shown at the bottom of the flowchart. Diapophyseal fossae are in blue, prezygapophyseal fossae are in green, and postzygapophyseal fossae are in yellow. The fossae that are not possible because they involve landmarks at opposite ends of the vertebra (e.g., prcpof, paspof) are rendered semi-transparent.</p

Representative vertebrae of <i>Apatosaurus louisae</i>.

<p>Anterior (top), left lateral (middle), and posterior (bottom) views of anterior cervical (cv 6), posterior cervical (cv 11), anterior dorsal (dv 3), posterior dorsal (dv 8), and anterior caudal (ca 2) vertebrae representing a single individual (CM 3018) and are to scale. Important changes along the column include the loss of the sprf and spof in bifid-spined posterior cervical and anterior dorsal vertebrae, appearance of the prcprf in posterior cervical vertebrae, and the division of the cdf into the cdf and cpaf in mid- and posterior dorsal vertebrae. Images modified from <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0017114#pone.0017114-Gilmore1" target="_blank">[52]</a>:pls. 24–26). Abbreviations and color scheme as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0017114#pone-0017114-g007" target="_blank">Figure 7</a>.</p

Configuration of vertebral laminae and fossae associated with the parapophysis in presacral vertebrae.

<p>Left, a cervical or anterior dorsal vertebra, in which the parapophysis is positioned on the centrum. Two laminae extend ventrally from the diapophysis (acdl, pcdl), helping to bound three fossae (prcdf, cdf, pocdf). Center, a simple mid- or posterior dorsal vertebra in which the parapophysis has risen onto the neural arch and is connected to the diapophysis and anterior centrum via two complementary laminae (ppdl, acpl). The configuration of fossae and their nomenclature, however, remains the same: the three fossae are still bounded by the zygapophyses, diapophysis, and centrum. Right, a complex mid- or posterior dorsal vertebra in which the parapophysis has risen onto the neural arch and four, rather than two, laminae extend from it (ppdl, acpl, pcpl, prpl). The addition of two laminae bisects the fossae between the diapophysis and centrum (cdf) and between the diapophysis, centrum, and prezygapophysis (prcdf). Four fossae are created, two of which require special naming (noted by asterisks). The fossa between the parapophysis and centrum does not contact the zygodiapophyseal table and thus lacks a primary landmark; in this case the parapophysis is enlisted as a primary landmark (cpaf). The fossa between the diapophysis, parapophysis, and prezygapophysis is not bounded by a secondary landmark (i.e., neural spine or centrum), and the parapophysis is enlisted as a secondary landmark (prpadf).</p

Representative vertebrae of <i>Brachiosaurus brancai</i>.

<p>Anterior (top), left lateral (middle), and posterior (bottom) views of anterior cervical (cv 3), middle cervical (cv 5), anterior dorsal (?dv 5), posterior dorsal (?dv 12), and anterior caudal (ca 1) vertebrae. Specimens come from several skeletally mature individuals (MB.R. 2180, MB.R. 3824, MB.R. 3822, MB.R. no number, see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0017114#pone.0017114-Janensch1" target="_blank">[45]</a>: pl. 2) and are to scale. Important changes along the column include the appearance of numerous irregular fossae in the sdf of cervical vertebrae and the absence of a cpaf in mid-dorsal vertebrae. Green/blue gradient in the lateral view of ca 1 indicates an undistinguishable pocdf + posdf. Photographs of ?dv 12 and ca 1 have been reversed. Abbreviations and color scheme as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0017114#pone-0017114-g007" target="_blank">Figure 7</a>.</p