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RE: Dinosaur news - Ngala - 06-21-2016
Aquatic adaptations in the four limbs of the snake-like reptile Tetrapodophis from the Lower Cretaceous of Brazil Lee et al., 2016
*This image is copyright of its original author
Credits: Michael Caldwell and Alessandro Palci (University of Alberta/Flinders University & South Australian Museum)
*This image is copyright of its original author
Reconstruction credits: Alessandro Palci and Michael Lee (Flinders University & South Australian Museum)
*This image is copyright of its original author
Fig. 3. (A) Forelimbs and (B) Hindlimbs of Tetrapodophis; a terrestrial squamate (Varanus); a marine dolichosaur (Pontosaurus), a marine mosasauroid (Tylosaurus); and a marine rhynchocephalian (Pleurosaurus). Numbers 1–5 identify highly distinctive limb similarities between Tetrapodophis and marine forms, discussed in the main text. Sources: Tetrapodophis after Martill et al. (2015) and Museum Solnhofen BMMS BK 2-2, Varanus albigularis after University of Alberta Museum of Zoology 947, Pontosaurus kornhuberi after Museo di Storia Naturale di Milano V3662, Tylosaurus proriger after Russell (1967), Pleurosaurus goldfussi after Cocude-Michel (1963), and Chalcides ocellatus after Young et al. (2009) and Field Museum of Natural History 164674.
Abstract:
"The exquisite transitional fossil Tetrapodophis – interpreted as a stem-snake with four small legs from the Lower Cretaceous of Brazil – has been widely considered a burrowing animal, consistent with recent studies arguing that snakes had fossorial ancestors. We reevaluate the ecomorphology of this important taxon using a multivariate morphometric analysis and a reexamination of the limb anatomy. Our analysis shows that the body proportions are unusual and similar to both burrowing and surface-active squamates. We also show that it exhibits striking and compelling features of limb anatomy, including enlarged first metapodials and reduced tarsal/carpal ossification – that conversely are highly suggestive of aquatic habits, and are found in marine squamates. The morphology and inferred ecology of Tetrapodophis therefore does not clearly favour fossorial over aquatic origins of snakes."
Other articles related:
Did snakes evolve from ancient sea serpents?
RE: Dinosaur news - Ngala - 06-23-2016
A new pterodactyloid pterosaur from the Early Cretaceous of the western part of Liaoning Province, northeastern China
Pangupterus liui Lü, Liu, Pan & Shen, 2016
*This image is copyright of its original author
Abstract:
"Pangupterus liui gen. et sp. nov. from the Jiufotang Formation of Sihedang, Lingyuan City, Liaoning Province is erected based on a nearly complete lower jaw. It is characterized by having a total of 36 slender curved teeth with sharp tips, forming a distinct fish-grabbing mechanism; the teeth are well-spaced and are circular in section; the length ratio of the mandibular symphysis to the whole jaw is 20%; and the ratio of the tooth root width to tooth length is 12%. Toothed pterosaurs make up about 56.3% of the pterosaur assemblage from the Jiufotang Formation, which indicates that toothed forms played a key role in the ecosystem."
RE: Dinosaur news - Ngala - 06-29-2016
Mummified precocial bird wings in mid-Cretaceous Burmese amber Xing et al., 2016
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This nearly 100-million-year-old wing tip features bones, soft tissue, and feathers preserved in amber. It was nicknamed "Angel" because it was originally intended to be used in a pendant called "Angel's Wings." Photo credits: Ryan C. McKellar
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Fig.1: (a) Mummified DIP-V-15100, showing rachises, skin, muscle and claws. (b) Skeletal morphology of DIP-V-15100, using different density threshold. © Mummified DIP-V-15101, showing rachises, skin, muscle and claws. (d) Skeletal morphology of DIP-V-15101. (e) Reconstruction of osteology based on the CT data. al, alular digit; am, alular metacarpal; ma, major digit; mam, major metacarpal; mi, minor digit; mim, minor metacarpal; ra, radius; ul, ulna. Scale bars, 5 mm.
Abstract:
"Our knowledge of Cretaceous plumage is limited by the fossil record itself: compression fossils surrounding skeletons lack the finest morphological details and seldom preserve visible traces of colour, while discoveries in amber have been disassociated from their source animals. Here we report the osteology, plumage and pterylosis of two exceptionally preserved theropod wings from Burmese amber, with vestiges of soft tissues. The extremely small size and osteological development of the wings, combined with their digit proportions, strongly suggests that the remains represent precocial hatchlings of enantiornithine birds. These specimens demonstrate that the plumage types associated with modern birds were present within single individuals of Enantiornithes by the Cenomanian (99 million years ago), providing insights into plumage arrangement and microstructure alongside immature skeletal remains. This finding brings new detail to our understanding of infrequently preserved juveniles, including the first concrete examples of follicles, feather tracts and apteria in Cretaceous avialans."
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RE: Dinosaur news - Ngala - 07-16-2016
An Unusual New Theropod with a Didactyl Manus from the Upper Cretaceous of Patagonia, Argentina
Gualicho shinyae Apesteguía, Smith, Valieri & Makovicky, 2016
*This image is copyright of its original author
Reconstruction credits: Jorge Gonzalez & Pablo Lara
*This image is copyright of its original author
Fig.1: C: Skeletal reconstruction of Gualicho shinyae showing recovered elements in white and missing elements in grey shading. Artwork by J. González.
Abstract:
Background
Late Cretaceous terrestrial strata of the Neuquén Basin, northern Patagonia, Argentina have yielded a rich fauna of dinosaurs and other vertebrates. The diversity of saurischian dinosaurs is particularly high, especially in the late Cenomanian-early Turonian Huincul Formation, which has yielded specimens of rebacchisaurid and titanosaurian sauropods, and abelisaurid and carcharodontosaurid theropods. Continued sampling is adding to the known vertebrate diversity of this unit.
Methodology/Principal Findings
A new, partially articulated mid-sized theropod was found in rocks from the Huincul Formation. It exhibits a unique combination of traits that distinguish it from other known theropods justifying erection of a new taxon, Gualicho shinyae gen. et sp. nov. Gualicho possesses a didactyl manus with the third digit reduced to a metacarpal splint reminiscent of tyrannosaurids, but both phylogenetic and multivariate analyses indicate that didactyly is convergent in these groups. Derived characters of the scapula, femur, and fibula supports the new theropod as the sister taxon of the nearly coeval African theropod Deltadromeus and as a neovenatorid carcharodontosaurian. A number of these features are independently present in ceratosaurs, and Gualicho exhibits an unusual mosaic of ceratosaurian and tetanuran synapomorphies distributed throughout the skeleton.
Conclusions/Significance
Gualicho shinyae gen. et sp. nov. increases the known theropod diversity of the Huincul Formation and also represents the first likely neovenatorid from this unit. It is the most basal tetatanuran to exhibit common patterns of digit III reduction that evolved independently in a number of other tetanuran lineages. A close relationship with Deltadromaeus from the Kem Kem beds of Niger adds to the already considerable biogeographic similarity between the Huincul Formation and coeval rock units in North Africa.
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Meet Gualicho shinyae, the puny-armed distant relative of T. rex
RE: Dinosaur news - Ngala - 07-22-2016
A New Megaraptoran Dinosaur (Dinosauria, Theropoda, Megaraptoridae) from the Late Cretaceous of Patagonia
Murusraptor barrosaensis Coria & Currie, 2016
*This image is copyright of its original author
Reconstruction credits: Jan Sovak
*This image is copyright of its original author
Fig 1. A) Skull reconstruction of Murusraptor barrosaensis, MCF-PVPH-411. B) Body reconstruction of Murusraptor barrosaensis, MCF-PVPH-411.
Both illustrations show recovered elements in white. Scale bars: A = 10 cm, B = 1 m.
Abstract:
"A skeleton discovered in the Upper Cretaceous Sierra Barrosa Formation (Turonian-Coniacian) of Neuquén Province, Argentina represents a new species of theropod dinosaur related to the long snouted, highly pneumatized Megaraptoridae. The holotype specimen of Murusraptor barrosaensis n.gen et n.sp. (MCF-PVPH-411) includes much of the skull, axial skeleton, pelvis and tibia. Murusraptor is unique in having several diagnostic features that include anterodorsal process of lacrimal longer than height of preorbital process, and a thick, shelf-like thickening on the lateral surface of surangular ventral to the groove between the anterior surangular foramen and the insert for the uppermost intramandibular process of the dentary. Other characteristic features of Murusraptor barrosaensis n.gen. et n. sp.include a large mandibular fenestra, distal ends of caudal neural spines laterally thickened into lateral knob-like processes, short ischia distally flattened and slightly expanded dorsoventrally. Murusraptor belongs to a Patagonian radiation of megaraptorids together with Aerosteon, Megaraptor and Orkoraptor. In spite being immature, it is a larger but more gracile animal than existing specimens of Megaraptor, and is comparable in size with Aerosteon and Orkoraptor. The controversial phylogeny of the Megaraptoridae as members of the Allosauroidea or a clade of Coelurosauria is considered analyzing two alternative data sets."
Other articles related:
Another Brick in the “Murus”: Meet the newest Megaraptoran theropod, Murusraptor
RE: Dinosaur news - Ngala - 07-25-2016
Multivariate and Cladistic Analyses of Isolated Teeth Reveal Sympatry of Theropod Dinosaurs in the Late Jurassic of Northern Germany Gerke & Wings, 2016
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The theropods of northern Germany. Credits: Hyrotrioskjan from DeviantArt
Abstract:
"Remains of theropod dinosaurs are very rare in Northern Germany because the area was repeatedly submerged by a shallow epicontinental sea during the Mesozoic. Here, 80 Late Jurassic theropod teeth are described of which the majority were collected over decades from marine carbonates in nowadays abandoned and backfilled quarries of the 19th century. Eighteen different morphotypes (A—R) could be distinguished and 3D models based on micro-CT scans of the best examples of all morphotypes are included as supplements. The teeth were identified with the assistance of discriminant function analysis and cladistic analysis based on updated datamatrices. The results show that a large variety of theropod groups were present in the Late Jurassic of northern Germany. Identified specimens comprise basal Tyrannosauroidea, as well as Allosauroidea, Megalosauroidea cf. Marshosaurus, Megalosauridae cf. Torvosaurus and probably Ceratosauria. The formerly reported presence of Dromaeosauridae in the Late Jurassic of northern Germany could not be confirmed. Some teeth of this study resemble specimens described as pertaining to Carcharodontosauria (morphotype A) and Abelisauridae (morphotype K). This interpretation is however, not supported by discriminant function analysis and cladistic analysis. Two smaller morphotypes (N and Q) differ only in some probably size-related characteristics from larger morphotypes (B and C) and could well represent juveniles of adult specimens. The similarity of the northern German theropods with groups from contemporaneous localities suggests faunal exchange via land-connections in the Late Jurassic between Germany, Portugal and North America."
RE: Dinosaur news - Ngala - 08-02-2016
Phylogenetic relationships of the Cretaceous Gondwanan theropods Megaraptor and Australovenator: the evidence afforded by their manual anatomy Novas, Rolando & Agnolin, 2016
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Figure 3. Left manus of Megaraptor namunhuaiquii (MUCPv 341) in dorsal view (A) and schematic representation (B) . Scale bar: 1 cm.
Abstract:
"General comparisons of the manual elements of megaraptorid theropods are conducted with the aim to enlarge the morphological dataset of phylogenetically useful features within Tetanurae. Distinctive features of Megaraptor are concentrated along the medial side of the manus, with metacarpal I and its corresponding digit being considerably elongated. Manual ungual of digit I is characteristically enlarged in megaraptorids, but it is also transversely compressed resulting in a sharp ventral edge. We recognize two derived characters shared by megaraptorans and coelurosaurs (i.e., proximal end of metacarpal I without a deep and wide groove continuous with the semilunar carpal, and metacarpals I and II long and slender), and one derived trait similar to derived tyrannosauroids (i.e., metacarpal III length <0.75 length of metacarpal II). However, after comparing carpal, metacarpal and phalangeal morphologies, it becomes evident that megaraptorids retained most of the manual features present in Allosaurus. Moreover, Megaraptor and Australovenator are devoid of several manual features that the basal tyrannosauroid Guanlong shares with more derived coelurosaurs (e.g., Deinonychus), thus countering our own previous hypothesis that Megaraptora is well nested within Tyrannosauroidea."
RE: Dinosaur news - Ngala - 08-03-2016
Stenorhynchosaurus munozi, gen. et sp. nov. a new pliosaurid from the Upper Barremian (Lower Cretaceous) of Villa de Leiva, Colombia, South America
Stenorhynchosaurus munozi Páramo-Fonseca, Gómez-Pérez, Noé & Etayo-Serna, 2016
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Figure 1. VL17052004-1, holotype specimen of Stenorhynchosaurus munozi gen. and sp. nov. General view of the specimen in dorsal view. Photography in the field and interpretation of the skeleton.
Abstract:
"From one of the most complete Lower Cretaceous rock sequences in the world (in Villa de Leiva region, central Colombia), we describe a new genus and species of pliosaurid plesiosaur Stenorhynchosaurus munozi. Stenorhynchosaurus displays a series of features which differentiate it from all the other Cretaceous pliosaurid genera: the anterior of the vomer, in ventral view, posterior of the palatal premaxilla-maxilla suture, contacting the posterior palatal process of the premaxilla level with the third maxillary alveolus; rostrum narrow and elongated with straight sides in dorsal view; lacrimal forming the anterior border and greater part of the ventral border of the orbit and broadly borders the maxilla anteriorly; anterior interpterygoid vacuity present; internal nares located between vomer and maxilla at the level of 13th-15th maxillary alveoli; anterior of rostrum and mandible without lateral expansion or marked increase in size of the functional alveoli; penultimate premaxillary alveolus slightly larger than adjacent premaxillary alveoli; homodont maxillary functional alveoli, with fourth tooth positions very slightly enlarged with respect to the neighboring alveoli; homodont dentary dentition; and epipodials extremely short. Based on morphological analysis of phylogenetic characters, Stenorhynchosaurus most likely nests within the increasingly inclusive Pliosauridae and Pliosauroidea, however, as currently defined, firm inference for referral of Stenorhynchosaurus to Thalassophonea is much more problematic, but ultimately seems likely based on characters shared with Pliosaurus and Brachaucheninae. However, this uncertainty indicates Thalassophonea requires rigorous redefinition. As to whether Stenorhynchosaurus is a member of the currently exclusively Jurassic genus Pliosaurus, or the Cretaceous sub-family Brachaucheninae, remains equivocal."
RE: Dinosaur news - Ngala - 08-04-2016
Crouching theropod at the seaside. Matching footprints with metatarsal impressions and theropod authopods: a morphometric approach Romano & Pitton, 2016
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Figure 7. Main phases of the movement made by the Riomartino trackmaker.
(a) Resting phase in ‘crouched’ position; (b) the trackmaker walks in a ‘crouched position’, while the right footprint is being definitively impressed; © initial rising up and defin-itive impression of the second left footprint; (d) final kick-off. Artwork credits: Davide Bonadonna
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Struthiomimus altus. Reconstruction credits: Davide Bonadonna
Abstract:
"We compare theropod footprints with elongate metatarsal prints from central Italy with known autopod structures in major theropod groups, in order to more accurately define the trackmaker attribution. Our work, using morphometric analysis, shows the considerable potential of explorative methods such as PCA (principal component analysis) and cluster analysis when describing important characters for a given taxonomic group (body and ichnofossils) and identifying important anatomical regions. Moreover, the results of the analysis suggest that the putative trackmaker is likely a member of Ornithomimosauria, with significant affinities in the posterior autopod structure with the genus Struthiomimus. The fundamental importance of integrating both osteological and ichnological data, when investigating locomotor and behavioural hypotheses, is highlighted. This approach could also contribute positively to the complex cognitive process of trackmaker identification and be favourable for the attainment of a more natural definition of ichnotaxa."
Full article
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Teropodi al mare!!
RE: Dinosaur news - Ngala - 08-15-2016
A new titanosaur (Dinosauria, Sauropoda) from the Upper Cretaceous of Lo Hueco (Cuenca, Spain)
Lohuecotitan pandafilandi Díaz, Mocho, Páramo, Escaso, Marcos-Fernández, Sanz & Ortega, 2016
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Reconstruction credits: Francisco Ortega
Abstract:
"The upper Campanian-lower Maastrichtian site of Lo Hueco (Cuenca, Spain) has provided a set of well-preserved partial skeletons in anatomical connection or with a low dispersion of their skeletal elements. One partial skeleton is herein described and a new titanosaurian sauropod is established, Lohuecotitan pandafilandi. This titanosaur is diagnosed by eight autapomorphic features: dorsally and ventrally widened or bifurcated posterior centrodiapophyseal lamina in anterior and middle dorsal vertebrae; short postspinal lamina with a transversely expanded distal end represented by smooth scars in the dorsal vertebrae; anteriormost caudals with the medial spinoprezygapophyseal and medial spinopostzygapophyseal laminae ventrally connected with the prespinal and postspinal laminae, respectively; anterior caudal neural spines with a dorsal projection of the prespinal and postspinal laminae; anterior caudal neural spines bears a “greek-cross”-like cross-section; middle caudal centra having two round and rough structures in the dorsal edge of the posterior articulation, which extends to the dorsal surface of the centrum; the articular ends of the rami of the haemal arches are divided in two articular surfaces; and tuberosity between the anterior and the lateral trochanter of the fibula. The herein performed phylogenetic analysis considered L. pandafilandi as a member of Lithostrotia more derived than Malawisaurus. The known palaeodiversity of the Late Cretaceous Ibero-Armorican titanosaurs is increasing, and further analyses focused on this group will be necessary to better understand the evolutionary history of European titanosaurs and to clarify their relationships within Titanosauria."
RE: Dinosaur news - Ngala - 08-31-2016
A Jurassic pterosaur from Patagonia and the origin of the pterodactyloid neurocranium
Allkaruen koi Codorniú, Carabajal, Pol, Unwin & Rauhut, 2016
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Reconstruction credits: G. L. Lio
Abstract:
"Pterosaurs are an extinct group of highly modified flying reptiles that thrived during the Mesozoic. This group has unique and remarkable skeletal adaptations to powered flight, including pneumatic bones and an elongate digit IV supporting a wing-membrane. Two major body plans have traditionally been recognized: the primitive, primarily long-tailed paraphyletic “rhamphorhynchoids” (preferably currently recognized as non-pterodactyloids) and the derived short-tailed pterodactyloids. These two groups differ considerably in their general anatomy and also exhibit a remarkably different neuroanatomy and inferred head posture, which has been linked to different lifestyles and behaviours and improved flying capabilities in these reptiles. Pterosaur neuroanatomy, is known from just a few three-dimensionally preserved braincases of non-pterodactyloids (as Rhamphorhynchidae) and pterodactyloids, between which there is a large morphological gap. Here we report on a new Jurassic pterosaur from Argentina, Allkaruen koi gen. et sp. nov., remains of which include a superbly preserved, uncrushed braincase that sheds light on the origins of the highly derived neuroanatomy of pterodactyloids and their close relatives. A µCT ray-generated virtual endocast shows that the new pterosaur exhibits a mosaic of plesiomorphic and derived traits of the inner ear and neuroanatomy that fills an important gap between those of non-monofenestratan breviquartossans (Rhamphorhynchidae) and derived pterodactyloids. These results suggest that, while modularity may play an important role at one anatomical level, at a finer level the evolution of structures within a module may follow a mosaic pattern."
RE: Dinosaur news - Ngala - 09-02-2016
A new Jehol enantiornithine bird with three-dimensional preservation and ovarian follicles
Linyiornis amoena Wang et al., 2016
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FIGURE 2. Photograph of the holotype of Linyiornis amoena , gen. et sp. nov., STM11- 80. A , skeleton on the main slab; B , close-up of the traces of fossilized ovarian follicles.
Abstract:
"We report a new enantiornithine bird, Linyiornis amoena gen. et sp. nov., from the Lower Cretaceous Jiufotang Formation in northeastern China. Traces of ovarian follicles indicate that the specimen represents a female individual. The nearly three-dimensional preservation of the new specimen reveals morphological details rarely visible in other Early Cretaceous enantiornithines, allowing more detailed comparison with Late Cretaceous enantiornithines. Differences in the preserved morphology of the right and left coracoids suggest that the appearance of some features is strongly affected by preservation, indicating that the distribution of these features in compressed specimens may need to be reevaluated. Like Late Cretaceous enantiornithine specimens, the holotype of Linyiornis amoena preserves a hypertrophied pit for muscle attachment on the bicipital crest but clearly did not preserve a fossa for the capital ligament, present in Late Cretaceous taxa; we discuss the functional morphology and implications of these features in Linyiornis amoena."
Full Article
RE: Dinosaur news - Ngala - 09-04-2016
Fish Hunting Ankylosaurs (Dinosauria, Ornithischia) from the Cretaceous of China Ji et al., 2016
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Reconstruction of Liaoningosaurus paradoxus.
Abstract:
"All ornithischian dinosaurs are herbivorous or omnivorous. Ornithischian Liaoningosaurus paradoxus Xu et al., 2001 is an ankylosaur. Here we report a new specimen of L. paradoxus from China. It contains a number of fish skeletons. We interpret those remains as stomach or gut contents and hence as strong evidence for the meat-eating diet of the dinosaur. With elongate and fork-like denticles of cheek tooth crowns, L. paradoxus has a dentition capable of penetrating into animals like small fishes. The carnivorous adaptation of the dinosaur is also supported by the ungual modification to a sharp claw in both the fore-and hind-limbs. The evolution of a shield-like ventral armor plate and the loose sacrum-pelvic connection suggest that L. paradoxus may have adopted an aquatic way of life,using the ventral armor plate to protect the body from underwater attacks; as such,the open suture between the neural arch and centrum of the vertebrae cannot be used to indicate the juvenile nature of the type specimen. L. paradoxus is the first carnivorous ornithischian dinosaur since dinosaur was first known in the 18th century and represents not only the first aquatic or semi aquatic example of armored dinosaurs but also the smallest species of ornithischian dinosaur so far known."
RE: Dinosaur news - Ngala - 09-04-2016
A new megalosaurid theropod dinosaur from the late Middle Jurassic (Callovian) of north-western Germany: implications for theropod evolution and faunal turnover in the Jurassic
Wiehenvenator albati Rauhut, Hübner & Lanser, 2016
*This image is copyright of its original author
*This image is copyright of its original author
FIGURE 4. Tentative reconstruction of the skull of Wiehenvenator albati, with the recovered elements shown in their approximate relation to each other. Scale bar equals 10 cm.
Abstract:
"Fragmentary remains of a large, robustly built theropod dinosaur were recovered from the marine middle Callovian Ornatenton Formation of north-eastern Northrhine-Westphalia, Germany. The specimen includes a premaxilla, maxilla, lacrimal, postorbital, dentary, several caudal vertebrae, ribs, fibulae, astragalus, and partial calcaneum. It is here described as a new species of megalosauroid, Wiehenvenator albati n. gen. n. sp., diagnosed by a strongly reduced maxillary antorbital fossa on the base of the ascending process of the maxilla, a very short anterior ramus of the lacrimal with an additional pneumatic depression anteroventral to the lacrimal fenestra, a transversely expanded orbital facet in the postorbital, and a laterally flexed proximal end of the ascending process of the astragalus. Phylogenetic analysis recovers Wiehenvenator as a megalosaurine megalosaurid, sister taxon to the Late Jurassic genus Torvosaurus. It thus adds to the considerable diversity of megalosauroids in the Middle Jurassic. A time-calibrated phylogeny of theropods indicates a rapid radiation of averostran theropods between the Toarcian and the Bathonian. This radiation was probably triggered by the Pliensbachian-Toarcian extinction event, which might have been more important for theropod evolution than the Triassic-Jurassic extinction. The fossil record indicates a faunal turnover from megalosauroid dominated Middle Jurassic to allosauroid / coelurosaur dominated Late Jurassic faunas. However, differences in the Middle and Late Jurassic theropod fossil records both in respect to geographic distribution of localities, as well as sampled environments make this inference problematic, at least in respect to allosauroids. An analysis of environmental preferences of allosauroids and megalosauroids indicates that the former preferred inland environments, whereas the latter are more common in nearshore environments."
RE: Dinosaur news - Ngala - 09-07-2016
A small azhdarchoid pterosaur from the latest Cretaceous, the age of flying giants Martin-Silverstone, Witton, Arbour & Currie, 2016
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Reconstruction credits: M. Witton
*This image is copyright of its original author
Figure 6. Speculative restoration of a 1.4 m wingspan azhdarchid, representing the atypically diminutive Late Cretaceous azhdarchoid specimen RBCM.EH.2009.019.0001, against a modern housecat (ca 300 mm tall at shoulder). All other Campanian and Maastrichtian azhdarchids are famous for being much larger, the biggest being as tall as giraffes and, even at their smallest, comparable in size to the largest extant flying birds. The pterosaur is restored here with anatomical characteristics and body proportions predicted for neoazhdarchian and azhdarchid azhdarchoid pterosaurs [30,42]. Reconstruction credits: M. Witton
Abstract:
"Pterosaur fossils from the Campanian–Maastrichtian of North America have been reported from the continental interior, but few have been described from the west coast. The first pterosaur from the Campanian Northumberland Formation (Nanaimo Group) of Hornby Island, British Columbia, is represented here by a humerus, dorsal vertebrae (including three fused notarial vertebrae), and other fragments. The elements have features typical of Azhdarchoidea, an identification consistent with dominance of this group in the latest Cretaceous. The new material is significant for its size and ontogenetic stage: the humerus and vertebrae indicate a wingspan of ca 1.5 m, but histological sections and bone fusions indicate the individual was approaching maturity at time of death. Pterosaurs of this size are exceedingly rare in Upper Cretaceous strata, a phenomenon commonly attributed to smaller pterosaurs becoming extinct in the Late Cretaceous as part of a reduction in pterosaur diversity and disparity. The absence of small juveniles of large species—which must have existed—in the fossil record is evidence of a preservational bias against small pterosaurs in the Late Cretaceous, and caution should be applied to any interpretation of latest Cretaceous pterosaur diversity and success."
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Our new pterosaur fossil shows birds and small reptiles flew side by side