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Dinosaur news
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An early Late Triassic long-necked reptile with a bony pectoral shield and gracile appendages
Ozimek volans Dzik & Sulej, 2016  *This image is copyright of its original author  *This image is copyright of its original author Abstract: "Several partially articulated specimens and numerous isolated bones of Ozimek volans gen. et sp. nov., from the late Carnian lacustrine deposits exposed at Krasiejów in southern Poland, enable a reconstruction of most of the skeleton. The unique character of the animal is its enlarged plate-like coracoids presumably fused with sterna. Other aspects of the skeleton seem to be comparable to those of the only known specimen of Sharovipteryx mirabilis from the latest Middle Triassic of Kyrgyzstan, which supports interpretation of both forms as protorosaurians. One may expect that the pectoral girdle of S. mirabilis, probably covered by the rock matrix in its only specimen, was similar to that of O. volans gen. et sp. nov. The Krasiejów material shows sharp teeth, low crescent scapula, three sacrals in a generalized pelvis (two of the sacrals being in contact with the ilium) and curved robust metatarsal of the fifth digit in the pes, which are unknown in Sharovipteryx. Other traits are plesiomorphic and, except for the pelvic girdle and extreme elongation of appendages, do not allow to identify any close connection of the sharovipterygids within the Triassic protorosaurians."
A Feathered Dinosaur Tail with Primitive Plumage Trapped in Mid-Cretaceous Amber Xing et al., 2016
 *This image is copyright of its original author Figure 1 Photomicrographs and SR X-Ray μCT Reconstructions of DIP-V-15103 (A) Dorsolateral overview. (B) Ventrolateral overview with decay products (bubbles in foreground, staining to lower right). © Caudal exposure of tail showing darker dorsal plumage (top), milky amber, and exposed carbon film around vertebrae (center). (D–H) Reconstructions focusing on dorsolateral, detailed dorsal, ventrolateral, detailed ventral, and detailed lateral aspects of tail, respectively. Arrowheads in (A) and (D) mark rachis of feather featured in Figure 4A. Asterisks in (A) and © indicate carbonized film (soft tissue) exposure. Arrows in (B) and (E)–(G) indicate shared landmark, plus bubbles exaggerating rachis dimensions; brackets in (G) and (H) delineate two vertebrae with clear transverse expansion and curvature of tail at articulation. Abbreviations for feather rachises: d, dorsal; dl, dorsalmost lateral; vl, ventralmost lateral; v, ventral. Scale bars, 5 mm in (A), (B), (D), and (F) and 2 mm in ©, (E), (G), and (H). Highlights: • The first non-avialan theropod fragments preserved in amber are described • Vertebral outlines, curvature, and plumage suggest a source within Coelurosauria • Branching structure in the feathers supports a barbule-first evolutionary pattern • Iron within carbonized soft tissue suggests traces of original material are present Summary: "In the two decades since the discovery of feathered dinosaurs [1, 2, 3], the range of plumage known from non-avialan theropods has expanded significantly, confirming several features predicted by developmentally informed models of feather evolution [4, 5, 6, 7, 8, 9, 10]. However, three-dimensional feather morphology and evolutionary patterns remain difficult to interpret, due to compression in sedimentary rocks [9, 11]. Recent discoveries in Cretaceous amber from Canada, France, Japan, Lebanon, Myanmar, and the United States [12, 13, 14, 15, 16, 17, 18] reveal much finer levels of structural detail, but taxonomic placement is uncertain because plumage is rarely associated with identifiable skeletal material [14]. Here we describe the feathered tail of a non-avialan theropod preserved in mid-Cretaceous (∼99 Ma) amber from Kachin State, Myanmar [17], with plumage structure that directly informs the evolutionary developmental pathway of feathers. This specimen provides an opportunity to document pristine feathers in direct association with a putative juvenile coelurosaur, preserving fine morphological details, including the spatial arrangement of follicles and feathers on the body, and micrometer-scale features of the plumage. Many feathers exhibit a short, slender rachis with alternating barbs and a uniform series of contiguous barbules, supporting the developmental hypothesis that barbs already possessed barbules when they fused to form the rachis [19]. Beneath the feathers, carbonized soft tissues offer a glimpse of preservational potential and history for the inclusion; abundant Fe2+ suggests that vestiges of primary hemoglobin and ferritin remain trapped within the tail. The new finding highlights the unique preservation potential of amber for understanding the morphology and evolution of coelurosaurian integumentary structures." Other articles related: First Dinosaur Tail Found Preserved in Amber Amber specimen offers rare glimpse of feathered dinosaur tail
Molecular evidence of keratin and melanosomes in feathers of the Early Cretaceous bird Eoconfuciusornis Pan et al., 2016
 *This image is copyright of its original author Significance: "We report fossil evidence of feather structural protein (beta-keratin) from a 130-My-old basal bird (Eoconfuciusornis) from the famous Early Cretaceous Jehol Biota, which has produced many feathered dinosaurs, early birds, and mammals. Multiple independent molecular analyses of both microbodies and associated matrix recovered from the fossil feathers confirm that these microbodies are indeed melanosomes. We use transmission electron microscopy and immunogold to show localized binding of antibodies raised against feather protein to matrix filaments within these ancient feathers. Our work sheds new light on molecular constituents of tissues preserved in fossils." Abstract: "Microbodies associated with feathers of both nonavian dinosaurs and early birds were first identified as bacteria but have been reinterpreted as melanosomes. Whereas melanosomes in modern feathers are always surrounded by and embedded in keratin, melanosomes embedded in keratin in fossils has not been demonstrated. Here we provide multiple independent molecular analyses of both microbodies and the associated matrix recovered from feathers of a new specimen of the basal bird Eoconfuciusornis from the Early Cretaceous Jehol Biota of China. Our work represents the oldest ultrastructural and immunological recognition of avian beta-keratin from an Early Cretaceous (∼130-Ma) bird. We apply immunogold to identify protein epitopes at high resolution, by localizing antibody–antigen complexes to specific fossil ultrastructures. Retention of original keratinous proteins in the matrix surrounding electron-opaque microbodies supports their assignment as melanosomes and adds to the criteria employable to distinguish melanosomes from microbial bodies. Our work sheds new light on molecular preservation within normally labile tissues preserved in fossils." Other articles related: Keratin and melanosomes preserved in 130-million-year-old bird fossil Feathers on This 130-Million-Year-Old Fossil Still Contain Traces of Color
Reappraisal of Europe’s most complete Early Cretaceous plesiosaurian: Brancasaurus brancai Wegner, 1914 from the “Wealden facies” of Germany Sachs, Hornung & Kear, 2016
 *This image is copyright of its original author Figure 2: Brancasaurus brancai Wegner, 1914, Isterberg Formation, upper Berriasian of Gronau (Westfalen), North Rhine-Westphalia. GPMM A3.B4 (holotype), mounted skeleton as originally displayed at the Geological-Palaeontological Museum in Münster (from Wegner, 1914): (A) Lateral and (B) dorsal views. Scale bar = 500 mm.  *This image is copyright of its original author Reconstruction credits: Joschua Knüppe Abstract "The holotype of Brancasaurus brancai is one of the most historically famous and anatomically complete Early Cretaceous plesiosaurian fossils. It derived from the Gerdemann & Co. brickworks clay pit near Gronau (Westfalen) in North Rhine-Westphalia, northwestern Germany. Stratigraphically this locality formed part of the classic European “Wealden facies,” but is now more formally attributed to the upper-most strata of the Bückeberg Group (upper Berriasian). Since its initial description in 1914, the type skeleton of B. brancai has suffered damage both during, and after WWII. Sadly, these mishaps have resulted in the loss of substantial information, in particular many structures of the cranium and limb girdles, which are today only evidenced from published text and/or illustrations. This non-confirmable data has, however, proven crucial for determining the relationships of B. brancai within Plesiosauria: either as an early long-necked elasmosaurid, or a member of the controversial Early Cretaceous leptocleidid radiation. To evaluate these competing hypotheses and compile an updated osteological compendium, we undertook a comprehensive examination of the holotype as it is now preserved, and also assessed other Bückeberg Group plesiosaurian fossils to establish a morphological hypodigm. Phylogenetic simulations using the most species-rich datasets of Early Cretaceous plesiosaurians incorporating revised scores for B. brancai, together with a second recently named Bückeberg Group plesiosaurian Gronausaurus wegneri (Hampe, 2013), demonstrated that referral of these taxa to Leptocleididae was not unanimous, and that the topological stability of this clade is tenuous. In addition, the trait combinations manifested by B. brancai and G. wegneri were virtually identical. We therefore conclude that these monotypic individuals are ontogenetic morphs and G. wegneri is a junior synonym of B. brancai. Finally, anomalies detected in the diagnostic features for other “Wealden” plesiosaurians have prompted reconsiderations of interspecies homology versus intraspecific variability. We therefore propose that the still unresolved taxonomy of B. brancai should emphasize only those character states evident in the examinable fossil material, and specifically accommodate for growth-related modifications delimited via osteologically mature referred specimens." Other articles related: Brancasaurus - a forgotten and beaten beauty
A bizarre Early Cretaceous enantiornithine bird with unique crural feathers and an ornithuromorph plough-shaped pygostyle
Cruralispennia multidonta Wang, O’Connor, Pan & Zhou, 2017  *This image is copyright of its original author Figure 1: Cruralispennia multidonta holotype (IVPP V21711). (a) Photograph; (b) line drawing. ca, caudal vertebra; cv, cervical vertebra; il, ilium; is, ischium; lad, left alular digit; lco, left coracoid; lde, left dentary; lfe, left femur; lhu, left humerus; lmd, left major digit; lpd; left pedal digits; lra, left radius; lta, left tarsometatarsus; lti, left tibiotarsus; lul, left ulna; pu, pubis; py, pygostyle; qu, quadrate; rco, right coracoid; rfe, right femur; rhu, right humerus; rmd, right major digit; rpd, right pedal digits; rra, right radius; rsc, right scapula; rta, right tarsometatarsus; rti, right tibiotarsus; rul, right ulna; sk, skull; st, sternum; sy, synsacrum; tv, thoracic vertebra. The white circles (numbered 1–5) and box indicate the locations of the feather and histological samples, respectively. Scale bar, 10 mm. Abstract: "Enantiornithes are the most successful clade of Mesozoic birds. Here, we describe a new enantiornithine bird, Cruralispennia multidonta gen. et sp. nov., from the Protopteryx-horizon of the Early Cretaceous Huajiying Formation of China. Despite being among the oldest known enantiornithines, Cruralispennia displays derived morphologies that are unexpected at such an early stage in the evolution of this clade. A plough-shaped pygostyle, like that of the Ornithuromorpha, evolved convergently in the Cruralispennia lineage, highlighting the homoplastic nature of early avian evolution. The extremely slender coracoid morphology was previously unknown among Early Cretaceous enantiornithines but is common in Late Cretaceous taxa, indicating that by 131 million years ago this clade had already experienced considerable morphological differentiation. Cruralispennia preserves unusual crural feathers that are proximally wire-like with filamentous distal tips, a new morphotype previously unknown among fossil or modern feathers, further increasing the known diversity of primitive feather morphologies."
Neck biomechanics indicate that giant Transylvanian azhdarchid pterosaurs were short-necked arch predators Naish & Witton, 2017
 *This image is copyright of its original author Figure 9: Diversity in predicted life appearance and ecologies for giant azhdarchid pterosaurs. (A) two giant, long-necked azhdarchids—the Maastrichtian species Arambourgiania philadelphiae—argue over a small theropod; (B) the similarly sized but more powerful Maastrichtian, Transylvanian giant azhdarchid pterosaur Hatzegopteryx sp. preys on the rhabdodontid iguanodontian Zalmoxes. Because large predatory theropods are unknown on Late Cretaceous Haţeg Island, giant azhdarchids may have played a key role as terrestrial predators in this community. Abstract: "Azhdarchid pterosaurs include the largest animals to ever take to the skies with some species exceeding 10 metres in wingspan and 220 kg in mass. Associated skeletons show that azhdarchids were long-necked, long-jawed predators that combined a wing planform suited for soaring with limb adaptations indicative of quadrupedal terrestrial foraging. The postcranial proportions of the group have been regarded as uniform overall, irrespective of their overall size, notwithstanding suggestions that minor variation may have been present. Here, we discuss a recently discovered giant azhdarchid neck vertebra referable to Hatzegopteryx from the Maastrichtian Sebeş Formation of the Transylvanian Basin, Romania, which shows how some azhdarchids departed markedly from conventional views on their proportions. This vertebra, which we consider a cervical VII, is 240 mm long as preserved and almost as wide. Among azhdarchid cervicals, it is remarkable for the thickness of its cortex (4–6 mm along its ventral wall) and robust proportions. By comparing its dimensions to other giant azhdarchid cervicals and to the more completely known necks of smaller taxa, we argue that Hatzegopteryx had a proportionally short, stocky neck highly resistant to torsion and compression. This specimen is one of several hinting at greater disparity within Azhdarchidae than previously considered, but is the first to demonstrate such proportional differences within giant taxa. On the assumption that other aspects of Hatzegopteryx functional anatomy were similar to those of other azhdarchids, and with reference to the absence of large terrestrial predators in the Maastrichtian of Transylvania, we suggest that this pterosaur played a dominant predatory role among the unusual palaeofauna of ancient Haţeg."
A new basal titanosaur (Dinosauria, Sauropoda) from the Lower Cretaceous of Brazil
Triunfosaurus leonardii Carvalho et al., 2017  *This image is copyright of its original author Highlights • A new Gondwanan Early Cretaceous (Berriasian – early Hauterivian) dinosaur species is described. • The specimen comes from the Rio Piranhas Formation, Triunfo Basin - Brazil. • It is one of the oldest described basal titanosaur ever recorded in Gondwana. • The discovery reinforces the South American origin for Titanosauria during the early Cretaceous. Abstract: "Although dinosaurian ichnofaunas are common in the Northeastern Brazilian Interior Basins, osteological remains are poorly represented in these areas. One of the main challenges in vertebrate paleontology in the Lower Cretaceous of this region is to recognize body-fossils, which can unveil the anatomy, functional morphology and paleoecological aspects of the dinosaurian fauna recorded until now only by footprints and trackways. The discovery of a new dinosaur specimen in the Rio Piranhas Formation of the Triunfo Basin opens new perspectives into the comprehension of paleogeographical and temporal distribution of the titanosaur sauropods. Titanosaurs are common in Upper Cretaceous rocks of Brazil and Argentina. The age of the Rio Piranhas Formation is considered to range from Berriasian to early Hauterivian. Thus, the description of this new species opens new viewpoints concerning the paleobiogeographical aspects of these sauropod dinosaurs." Full Article
Mexican ceratopsids: Considerations on their diversity and biogeography
Yehuecauhceratops mudei Rivera-Sylva, Frey, Stinnesbeck, Guzmán-Gutiérrez & González-Gonzáleza, 2017  *This image is copyright of its original author Abstract: "During the past decade, three taxa of ceratopsid ornithischians have been described from Mexico. Apparently, this group experienced a regional diversification in this area. To date Mexican Ceratopsia are represented by three species, one of which is a centrosaurine and two are chasmosaurines. Here we provide a critical review on Mexican ceratopsians and formally name a new centrosaurine ceratopsid species from the Campanian Aguja Formation as Yehuecauhceratops mudei. We also discuss possible causes for the rapid endemic diversification of Mexican ceratopsians." Full Article
A new basal sauropodiform dinosaur from the Lower Jurassic of Yunnan Province, China
Xingxiulong chengi Wang, You & Wang, 2017  *This image is copyright of its original author Figure 2: Representative elements of Xingxiulong chengi gen. et sp. nov. and reconstruction of the skeleton. (a) Cervical vertebrae of LFGT-D0001 (3–10); (b) articulated posterior dorsal vertebrae (10–14) and dorsosacral of LFGT-D0001 in lateral and dorsal views; © scapula with articulated dorsal vertebrae of LFGT-D0003 in left lateral view; (d) left humerus of LFGT-D0003 in posterior and anterior views; (e) left forelimb of LFGT-D0003 in medial view; (f) right articulated humerus, ulna and radius in medial view, and detail of the proximal end of ulna and radius; (g) left ilium of LFGT-D0002 (photograph and line drawing) in lateral view; (h) right ilium of LFGT-D0003 in lateral view; (i) right ischium of LFGT-D0002 in lateral view; (j) left femur of LFGT-D0002 in anterior, lateral, posterior and medial views; (k) distal end of left tibia of LFGT-D0003 in anterior and distal views; (l) left astragalus of LFGT-D0002 in posterior view; (m) left pes of LFGT-D0002 in lateral and ventral views; (n) right pes of LFGT-D0002 in dorsal and ventral views, with detailed metatarsal I in dorsal view; (o) reconstruction of the skeleton of Xingxiulong chengi gen. et sp. nov. (scaled to the size of the holotype). Abbreviations: 4t, fourth trochanter; alp, anterolateral process; ds, dorsosacral; epls, expanded plate-like summit; it, internal tuberosity; ls, longitudinal sulcus; lt, lesser trochanter; mt I, metatarsal I; mt V, metatarsal V; plp, posterolateral process; pmb, posterior median bulge; pop, postacetabular process; prp, preacetabular process. Dashed lines represent highlighting (c,b, and f) or reconstruction (g and h). Scale bars equal 10 cm in (a–n) and 1 m in (o). Abstract: "The Lufeng Formation in Lufeng Basin of Yunnan Province, southwestern China preserves one of the richest terrestrial Lower Jurassic vertebrate faunas globally, especially for its basal sauropodomorphs, such as Lufengosaurus and Yunnanosaurus. Here we report a new taxon, Xingxiulong chengi gen. et sp. nov. represented by three partial skeletons with overlapping elements. Xingxiulong possesses a number of autapomorphies, such as transversely expanded plate-like summit on top of the neural spine of posterior dorsal vertebrae, four sacral vertebrae, robust scapula, and elongated pubic plate approximately 40% of the total length of the pubis. Phylogenetic analysis resolves Xingxiulong as a basal member of Sauropodiformes, and together with another two Lufeng basal sauropodiforms Jingshanosaurus and Yunnanosaurus, they represent the basalmost lineages of this clade, indicating its Asian origin. Although being relatively primitive, Xingxiulong displays some derived features normally occurred in advanced sauropodiforms including sauropods, such as a four sacral-sacrum, a robust scapula, and a pubis with elongated pubic plate. The discovery of Xingxiulong increases the diversity of basal sauropodomorphs from the Lufeng Formation and indicates a more complicated scenario in the early evolution of sauropodiforms."
New evidence from China for the nature of the pterosaur evolutionary transition
Douzhanopterus zhengi Wang et al., 2017  *This image is copyright of its original author Figure 1: The holotype of Douzhanopterus zhengi gen. et sp. nov. (a) Part of the holotype; (b) close up of the tail, green arrows indicating the anterior and posterior ends of each caudal vertebra; © close up of the right foot. Scale bars are 50 mm, 10 mm, and 10 mm in (a,b and c), respectively. Abstract: "Pterosaurs are extinct flying reptiles, the first vertebrates to achieve powered flight. Our understanding of the evolutionary transition between basal, predominantly long-tailed forms to derived short-tailed pterodactyloids remained poor until the discovery of Wukongopterus and Darwinopterus in western Liaoning, China. In this paper we report on a new genus and species, Douzhanopterus zhengi, that has a reduced tail, 173% the length of the humerus, and a reduced fifth pedal digit, whose first phalange is ca. 20% the length of metatarsal III, both unique characters to Monofenestra. The morphological comparisons and phylogenetic analysis presented in this paper demonstrate that Douzhanopterus is the sister group to the ‘Painten pro-pterodactyloid’ and the Pterodactyloidea, reducing the evolutionary gap between long- and short-tailed pterosaurs."
A New Ophthalmosaurid (Ichthyosauria) from Svalbard, Norway, and Evolution of the Ichthyopterygian Pelvic Girdle
Keilhauia nui Delsett, Roberts, Druckenmiller & Hurum, 2017  *This image is copyright of its original author Reconstruction credits: Esther van Hulsen Abstract: "In spite of a fossil record spanning over 150 million years, pelvic girdle evolution in Ichthyopterygia is poorly known. Here, we examine pelvic girdle size relationships using quantitative methods and new ophthalmosaurid material from the Slottsmøya Member Lagerstätte of Svalbard, Norway. One of these new specimens, which preserves the most complete ichthyosaur pelvic girdle from the Cretaceous, is described herein as a new taxon, Keilhauia nui gen. et sp. nov. It represents the most complete Berriasian ichthyosaur known and the youngest yet described from the Slottsmøya Member. It is diagnosed on the basis of two autapomorphies from the pelvic girdle, including an ilium that is anteroposteriorly expanded at its dorsal end and an ischiopubis that is shorter or subequal in length to the femur, as well as a unique character combination. The Slottsmøya Member Lagerstätte ichthyosaurs are significant in that they represent a diverse assemblage of ophthalmosaurids that existed immediately preceding and across the Jurassic–Cretaceous boundary. They also exhibit considerable variation in pelvic girdle morphology, and expand the known range in size variation of pelvic girdle elements in the clade." Other articles related: Nyoppdaget fiskeøgle oppkalt etter Natur og Ungdom
A new polycotylid plesiosaur with extensive soft tissue preservation from the early Late Cretaceous of northeast Mexico
Mauriciosaurus fernandezi Frey et al., 2017  *This image is copyright of its original author Figure 3 : Mauriciosaurus fernandezi INAH CPC RFG 2544 P.F.1. A) Photograph of the specimen after preparation, B) interpretative line drawing. Note the massive tail base and the dorsal skin preserved between the ribs. Abstract: "A nearly complete skeleton of a polycotylid plesiosaur is described from the early Late Cretaceous laminated limestones at Vallecillo, northeast Mexico. It shows extensive soft tissue preservation. In some exceedingly well preserved areas there are transversely elongate rectangular to trapezoid millimetric scale-like structures arranged in longitudinal rows. The trailing edge skin flap preserves fibers and scale rows perpendicular to the trailing edge. A thick layer of subdermal tissue is present, especially along the tail base. It was responsible for the hydrodynamic drop-shaped body contour, with the body and tail forming a single unit. The body shape determined from the preserved soft tissues suggests a swimming speed similar to extant leatherback turtles. Based on the unique osteology of the palate, which is intermediate between Dolichorhynchops and Trinacromerum, and according to the unique morphology of the girdles and propodials as well as the medially converging gastralia, the new specimen is placed in a new genus and species of Polycotylidae, Mauriciosaurus fernandezi gen. et sp. nov." Other articles related: Paleo Profile: Mauricio Fernández's Plesiosaur
A new primitive Neornithischian dinosaur from the Jurassic of Patagonia with gut contents
Isaberrysaura mollensis Salgado et al., 2017  *This image is copyright of its original author Figure 3. Gut content of Isaberrysaura mollensis gen. et sp. nov. (a–c), seeds of cycads ©, and other seeds (s); rib ®. (d,e) Detail of seeds of cycads: sarcotesta (sa), sclerotesta (sc), coronula ©, nucellus (n). (f) Location of the gut content in the reconstructed skeleton of Isaberrysaura mollensis gen. et sp. nov. The drawings were processed using Adobe Photoshop CS2 Serial Number: 1045-1412-5685-1654-6343-1431. Abstract: "We describe a new species of an ornithischian dinosaur, Isaberrysaura mollensis gen. et sp. nov. The specimen, consisting in an almost complete skull and incomplete postcranium was collected from the marine-deltaic deposits of the Los Molles Formation (Toarcian-Bajocian), being the first reported dinosaur for this unit, one of the oldest from Neuquén Basin, and the first neornithischian dinosaur known from the Jurassic of South America. Despite showing a general stegosaurian appearance, the extensive phylogenetic analysis carried out depicts Isaberrysaura mollensis gen. et sp. nov. as a basal ornithopod, suggesting that both Thyreophora and neornithischians could have achieved significant convergent features. The specimen was preserved articulated and with some of its gut content place in the middle-posterior part of the thoracic cavity. Such stomach content was identified as seeds, most of them belonging to the Cycadales group. This finding reveals a possible and unexpected role of this ornithischian species as seed-dispersal agent."
Vegasaurus molyi, gen. et sp. nov. (Plesiosauria, Elasmosauridae), from the Cape Lamb Member (lower maastrichtian) of the Snow Hill Island Formation, Vega Island, Antarctica, and remarks on Wedellian Elasmosauridae
Vegasaurus molyi O'Gorman, Salgado, Olivero & Marenssi, 2017  *This image is copyright of its original author Abstract: "A new elasmosaurid, Vegasaurus molyi, gen. et sp. nov., from Vega Island, James Ross Archipelago, Antarctica, is described. The holotype and only specimen of this species (MLP 93-I-5-1) was collected from the lower Maastrichtian Cape Lamb Member of the Snow Hill Island Formation. Vegasaurus molyi is the only Antarctic elasmosaurid and one of only a few Late Cretaceous elasmosaurids from the Southern Hemisphere whose postcranial anatomy is well known. Vegasaurus molyi is distinguished from other elasmosaurids by the following combination of characters: cervical region with 54 vertebrae with elongated centra, dumbbell-shaped articular faces and lateral ridge present in the anterior and middle parts of the neck but absent in the posterior-most cervical vertebrae; scapula with ventral ramus bearing a strong ridge in the anteromedial corner of its dorsal surface; ilium shaft with expanded distal end, divided into two parts forming an angle of 140° opening anteriorly; and humerus with anterior knee and prominent posterior projection with accessory posterior articular facet. Preliminary phylogenetic analysis places V. molyi within a clade that includes the Late Cretaceous Wedellian aristonectine elasmosaurids, Aristonectes and Kaiwhekea. This indicates a close relationship between Aristonectinae and non-Aristonectinae Late Cretaceous Weddellian elasmosaurids and suggests a Weddellian origin for the Aristonectinae." Full Article Other articles related: Nueva especie de Plesiosaurio en Antártida Hallan una nueva especie de plesiosaurio en la Antártida
A new hypothesis of dinosaur relationships and early dinosaur evolution Baron, Norman & Barrett, 2017
 *This image is copyright of its original author Figure 1: Phylogenetic relationships of early dinosaurs. Time calibrated strict consensus of 94 trees from an analysis with 73 taxa and 457 characters (see Supplementary Information). A, the least inclusive clade that includes Passer domesticus, Triceratops horridus and Diplodocus carnegii—Dinosauria, as newly defined. B, the least inclusive clade that includes P. domesticus and T. horridus—Ornithoscelida, as defined. C, the most inclusive clade that contains D. carnegii, but not T. horridus—Saurischia, as newly defined. For further information on definitions see Table 1. All subdivisions of the time periods (white and grey bands) are scaled according to their relative lengths with the exception of the Olenekian (Early Triassic), which has been expanded relative to the other subdivisions to better show the resolution within Silesauridae and among other non-dinosaurian dinosauromorphs. Abstract: "For 130 years, dinosaurs have been divided into two distinct clades—Ornithischia and Saurischia. Here we present a hypothesis for the phylogenetic relationships of the major dinosaurian groups that challenges the current consensus concerning early dinosaur evolution and highlights problematic aspects of current cladistic definitions. Our study has found a sister-group relationship between Ornithischia and Theropoda (united in the new clade Ornithoscelida), with Sauropodomorpha and Herrerasauridae (as the redefined Saurischia) forming its monophyletic outgroup. This new tree topology requires redefinition and rediagnosis of Dinosauria and the subsidiary dinosaurian clades. In addition, it forces re-evaluations of early dinosaur cladogenesis and character evolution, suggests that hypercarnivory was acquired independently in herrerasaurids and theropods, and offers an explanation for many of the anatomical features previously regarded as notable convergences between theropods and early ornithischians." The old family tree structure. Credit: University of Cambridge  *This image is copyright of its original author The new family tree structure. Credit: University of Cambridge  *This image is copyright of its original author Other articles related: Shaking Up the Dinosaur Family Tree New study shakes up the dinosaur family tree Dinosaur family tree poised for colossal shake-up Ornithoscelida Rises: A New Family Tree for Dinosaurs New study shakes the roots of the dinosaur family tree New study shakes the roots of the dinosaur family tree A 130-Year-Old Fact About Dinosaurs Might Be Wrong New idea shakes up dinosaur family tree for T. Rex and pals A new theory could overturn one of the most central ‘facts’ about dinosaurs Radical shakeup of dinosaur family tree points to unexpected Scottish origins |
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