Dinosauria Research Papers - Academia.edu (original) (raw)

- by Philip J. Currie
- •
- Paleontology, Cannibalism, Vertebrate Paleontology, Multidisciplinary

At the end of the Cretaceous, 65.5 million years ago, the giant ceratopsids Triceratops and Torosaurus dominated North America’s dinosaur fauna. The origins of these giant ceratopsids, the Triceratopsini, are poorly understood. This paper describes Titanoceratops ouranos, a giant ceratopsid from the late Campanian (73–74 Ma) of New Mexico, and the earliest known triceratopsin. The holotype was previously interpreted as an aberrant and exceptionally large specimen of Pentaceratops sternbergi, but the animal does not show the diagnostic features of Pentaceratops. Instead, cladistic analysis shows that Titanoceratops is the sister taxon of a clade formed by Eotriceratops, Triceratops, and Torosaurus. With an estimated mass of 6.5 tons, Titanoceratops is among the largest dinosaurs known from the Campanian of North America, and rivaled Triceratops in size. The recognition of Titanoceratops suggests that giant chasmosaurines evolved once, among the Triceratopsini, and that the group evolved large size five million years earlier than previously thought. The giant horned dinosaurs probably originated in the southern part of the North American continent during the Campanian but only became widespread during the Maastrichtian.

- by Nicholas R Longrich
- •
- Geology, Dinosauria, Cretaceous, Body Size
- by Philip J. Currie
- •
- Biology, Dinosaur Paleontology, Theropoda, Dinosauria

A new alvarezsaur, Albertonykus borealis, is described from the Lower Maastrichtian of the Horseshoe Canyon Formation, Alberta, Canada. Forelimb and hindlimb elements from at least two individuals were recovered from the Albertosaurus bonebed at Dry Island Provincial Park, along with pedal phalanges from nearby localities. Phylogenetic analysis shows that Albertonykus is the sister taxon of the Asian clade Mononykinae, consistent with the hypothesis that the alvarezsaurs originated in South America, and then dispersed to Asia via North America. The discovery of Albertonykus provides important insights into the biology of the Alvarezsauridae. As in other alvarezsaurs, the forelimbs of Albertonykus are specialized for digging, but they are too short to permit burrowing; they were most likely used to dig into insect nests. Potential prey items are evaluated in light of the fossil record of social insects. Ants were a minor part of the ecosystem during the Cretaceous, and mound-building termites do not appear until the Eocene. This leaves the possibility that Albertonykus preyed on wood-nesting termites. We tested this hypothesis by examining silicified wood from the Horseshoe Canyon Formation. It was found that this wood frequently contains borings, which resemble the galleries of dampwood termites (Termopsidae).

- by Philip Currie and +1
- •
- Paleobiology, Geology, Vertebrate Paleontology, Theropods
- by Herve Bocherens
- •
- Biomolecular archaeology, Dinosaur Paleontology, Dinosauria, Dinosaurs

Tyrannosaurus rex was one of the largest terrestrial carnivores of all time, and consequently its ecology and diet have been the focus of much discussion. However, there is little direct evidence of diet or feeding habits in this species. Examination of museum collections has revealed four specimens of Tyrannosaurus rex that bear tooth marks made by large, carnivorous dinosaurs. Because Tyrannosaurus is the only large carnivore known from the Late Maastrichtian of western North America, we infer that Tyrannosaurus made these tooth marks. The marks are interpreted as feeding traces and these fossils therefore record instances of cannibalism. Given that this behavior has a low preservation potential, cannibalism seems to have been a surprisingly common behavior in Tyrannosaurus, and this behavior may have been relatively common in carnivorous dinosaurs.

- by Nicholas R Longrich and +1
- •
- Paleontology, Cannibalism, Vertebrate Paleontology, Multidisciplinary

The "Tooth Draw Deposit" is an extensive, high diversity, multitaxic, dinosaur-rich, bone bed in the latest Cretaceous, Hell Creek Formation. The mapped portions of the deposit show a complex channel lag formed by a combination of both abiotic and biotic processes, at least 40 meters wide and well over 180 meters long. It is composed of interbedded sandstones and conglomerates representing fluvial, riverine deposition, a portion of which shows evidence of hyper-concentrated or debris flow rates. This lag has been sampled in different locations including the main "Tooth Draw Quarry (TD)", "Tooth Draw West (TDW)", "Tooth Draw South (TDS)" and "Becca's Tooth Draw (BTD)". To date, several thousand vertebrate specimens have been recovered over the last 15 years of work. These elements include both dinosaur and non-dinosaur remains, showing a diverse fauna of at least 21 dinosaur and over 48 vertebrate genera. Taphonomic markers indicate that there are at least two distinct communities represented by the deposit. One that represents a more localized fauna, caught up in the initial formation of the lag and another that represents reworked, hydraulically emplaced elements, likely accumulating from further upstream (parautochthonous). Many of the reworked elements show pre-depositional breaks, spiral fractures, bite marks, insect borings, and evidence of sub-aerial exposure. Tyrannosaurid teeth make up over 30% of the logged specimens, over 700 teeth, with more added each year. Dromaeosaurid teeth are also fairly common with over 180 specimens to date. Given the high numbers of shed theropod teeth, and the broken and bite marked bones, the most parsimonious conclusion is that portions of the Tooth Draw assemblage represent the remains of multiple seasons of feeding activity a short distance upstream along the ancient river system.

- by Walter Stein
- •
- Vertebrate Paleontology, Cretaceous life, Dinosaur Paleontology, Dinosauria
- by Claudia Serrano
- •
- Paleobiology, Paleontology, Vertebrate Paleontology, Dinosaur Paleontology

L’appassionante vicenda della scoperta del sito a orme di dinosauri nella campagna molfettese ha inizio nella primavera del 2005. A partire dall’autunno del 2007, la notizia rimbalza diverse volte sui giornali locali, sia online sia sulla carta stampata, giungendo col tempo a occupare anche spazi d’approfondimento sui canali televisivi a livello regionale e nazionale.
Sebbene spesso abbia raccontato le circostanze che mi videro protagonista del rinvenimento di uno dei patrimoni più singolari della città di Molfetta, dal valore storico e scientifico inestimabile, ho sempre rimandato la stesura di uno scritto che raccontasse i fatti avvenuti prima che la notizia diventasse di dominio pubblico; il proposito di questo racconto, pertanto, è quello di fissare i ricordi e far luce sui fatti che portarono alla scoperta del sito ad orme di dinosauri nella cava in contrada San Leonardo, da tempo considerato tra i più importanti d’Italia e del mondo.

- by Cesare Davide Andriani
- •
- Geology, Ichnology, Vertebrate Ichnology, Vertebrate Paleontology

A nearly complete, well-preserved maxilla of an abelisaurid theropod from the early Late Cretaceous (middle Cenomanian-Turonian) Lower Member of the Bajo Barreal Formation of Chubut, Argentina represents the first definitive member of the abelisaurid clade from pre-Senonian (Coniacian–Maastrichtian) deposits. The new maxilla shares derived characters with the maxillae of Carnotaurus and Majungatholus, and with AMNH 1955, a maxilla previously referred to Indosuchus, suggesting that it pertains to the abelisaurid subclade Carnotaurinae. Abelisaurus shares apomorphic characters with Carnotaurinae, but many of these characters are also found in the carcharodontosaurid allosauroid Giganotosaurus. As it is known only from cranial material lacking carnotaurine synapomorphies, Abelisaurus may represent a late-surviving carcharodontosaurid derivative.
The presence of the Bajo Barreal predator in the early Late Cretaceous indicates that the origin of Abelisauridae had occurred by then. The occurrence of the new maxilla is nearly concurrent with the accepted interval of tectonic divergence between South America and Africa. Its discovery thus weakens support for the recent hypothesis that the abelisaurid clade could not have penetrated Africa. The known occurrence of Abelisauridae may reflect a former pan- Gondwanan distribution, and is thus of limited utility in the support of Late Cretaceous paleogeographic hypotheses.

- by Matthew Lamanna
- •
- Dinosaur Paleontology, Theropods, Dinosaurian Paleontology, Theropoda

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.

- by Hermínio Araújo-Júnior
- •
- Evolutionary Biology, Paleontology, Evolution, Dinosauria

Die cenomane Wadi Milk Formation des Sudan lieferte eine reiche kontinentale Wirbeltierfauna. Neben Fragmenten von großen Theropoden verweisen disartikulierte Fußphalangen-Elemente und ein Zahn auf die Existenz von dromaeosauriden Theropoden in der Oberkreide des Sudan; damit ist diese Theropodenfamilie zum ersten Mal auf den Gondwana-Kontinenten nachgewiesen. The Cenomanian Wadi Milk Formation in Sudan yielded a rich continental vertebrate fauna. Apart from big theropod fragments, some disarticulated elements of a pes and a tooth indicate the presence of a dromaeosaurid theropod in the Late Cretaceous of Sudan. This is the first record of this theropod family from Gondwanian continents.

- by Federico Fanti and +2
- •
- Geology, Brazil, Theropoda, Dinosauria

Впервые описанный 70 лет назад гадрозаврид Orthomerus weberi основан преимущественно на
костях нижнего отдела задней лапы из маастрихта (верхний мел) Крымского полуострова,
Россия. Отсутствие костей черепа, таза и позвоночного столба сильно усложняют
диагностирование Orthomerus weberi , однако, новые данные о утконосых динозаврах,
накопленные за эти десятилетия, а также сравнение крымских останков с другими
представителями Hadrosauria, показывают комбинацию уникальных признаков, позволяющих
создать для данного вида свой отдельный род Riabininohadros gen. nov.

- by Roman Ulansky
- •
- Dinosaur Paleontology, Dinosauria, Hadrosaurs

Herrerasauridae comprises a basal clade of dinosaurs best known from the Upper Triassic of Argentina and
Brazil, which have yielded remains of Herrerasaurus ischigualastensis and Staurikosaurus pricei, respectively.
Systematic opinion regarding the position of Herrerasauridae at the base of Dinosauria has varied. Here
we describe a new herrerasaurid, Sanjuansaurus gordilloi gen. n., sp. n., based on a partial skeleton from
Carnian-age strata of the the Upper Triassic Ischigualasto Formation of northwestern Argentina. Th e
new taxon is diagnosed by numerous features, including long, band-shaped and posterolaterally oriented
transverse process on the posterior cervical vertebrae; neural spines of the sixth to eighth dorsal vertebrae,
at least, bearing acute anterior and posterior processes; scapula and coracoid with everted lateral margins
of the glenoid; and short pubis (63% of the femoral length). Phylogenetic analysis placed Sanjuansaurus
within a monophyletic Herrerasauridae, at the base of Theropoda and including Herrerasaurus and Staurikosaurus.
Th e presence of Sanjuansaurus at the base of the Ischigualasto Formation, along with other
dinosaurs such as Herrerasaurus, Eoraptor, Panphagia, and Chromogisaurus suggests that saurischian dinosaurs
in southwestern Pangea were already widely diversifi ed by the late Carnian rather than increasing in
diversity across the Carnian-Norian boundary.

Matthew Grant Baron - PhD Thesis (University of Cambridge), Appendix 1 (Taxa)

- by Matthew Baron
- •
- Systematics (Taxonomy), Paleontology, Phylogenetics, Taxonomy

Although diplodocoid sauropods from Africa and the Americas are well known, their European record remains largely neglected. Here we redescribe Dinheirosaurus lourinhanensis from the Late Jurassic of Portugal. The holotype comprises two posterior cervical vertebrae, the dorsal series and a caudal centrum. Redescription demonstrates its validity on the basis of three autapomorphies:(1) posteriorly restricted ventral keel on posterior cervical vertebrae;(2) three small subcircular fossae posterior to the lateral coel ...

- by Paul Upchurch
- •
- Evolutionary Biology, Geology, Paleontology, Ecology
- by Elizabeth Freedman Fowler
- •
- Geology, Paleontology, Biomechanics, Functional Anatomy

Prosauropods are basal sauropodomorphs that were the major terrestrial faunal components from the
Norian until their extinction during the Toarcian. Their status as a natural group is debatable. In the present work I
describe Adeopapposaurus mognai, a new sauropodomorph from the Can˜o´n del Colorado Formation, in northwestern
Argentina. Diagnostic autapomorphies and combination of characters of Adeopapposaurus include a series of large
foramina in a sub-vertical row on the lateral surface of the premaxilla; strongly rugose depression bordered by a
protuberance with a series of foramina in a sub-vertical row, on the lateral surface of the anterior end of the dentary;
eleven anteroposteriorly elongated cervical vertebrae and thirteen dorsal vertebrae with neural arches taller than the
respective centra. Phylogenetically Adeopapposaurus is resolved as the sister group to Massospondylus; differing from the
latter based on differences in mandible and premaxilla and addition of one dorsal vertebra to the neck. The specimens
described here reveal numerous herbivorous adaptations, including the presence of a highly vascularized bony plate in the
premaxilla and dentary, which indicates that it had a horny beak.

Knowledge of dinosaur footprints has greatly changed how scientists reconstruct the palaeoenvironment and palaeogeography of the Mesozoic carbonate platforms of the Periadriatic area (Italy, Slovenia and Croatia). Geologists
considered those carbonate platforms as shallow marine, intraoceanic banks (i.e., surrounded by the Tethys Ocean) during
Cretaceous times. The discovery in the last 20 years of dinosaur fossils, mainly footprints, in many places and at different
stratigraphic levels has demonstrated that the “shallow seas” were repeatedly or continuously populated by large terrestrial
animals. Thus, the reconstructions of those carbonate platforms as a sort of Mesozoic “Bahamas Banks” was incorrect. The
new record allows also testing for congruence with palaeoenvironmental and palaeogeographic reconstructions. Areas where dinosaur fossils have been found are always considered as “shallow marine” in those reconstructions, very far away from continental areas during the Late Triassic and earliest Jurassic and surrounded by deep marine basins during Late Jurassic and Cretaceous times. The results of this research are a first step toward the understanding of those dinosaurs living “at the border”, but are obviously preliminary and subject to confirmation or confutation with increased fossil sampling. The ichnological sample and the palaeogeographic reconstructions can also stimulate some reflections about the biology of the extinct dinosaurian clades and give some suggestions for the development of future research.

Most non-avian theropod dinosaurs are characterized by fearsome serrated teeth and sharp recurved claws. Interpretation of theropod predatory ecology is typically based on functional morphological analysis of these and other physical features. The notorious hypertrophied ‘killing claw’ on pedal digit (D) II of the maniraptoran theropod Deinonychus (Paraves: Dromaeosauridae) is hypothesized to have been a predatory adaptation for slashing or climbing, leading to the suggestion that Deinonychus and other dromaeosaurids were cursorial predators specialized for actively attacking and killing prey several times larger than themselves. However, this hypothesis is problematic as extant animals that possess similarly hypertrophied claws do not use them to slash or climb up prey. Here we offer an alternative interpretation: that the hypertrophied D-II claw of dromaeosaurids was functionally analogous to the enlarged talon also found on D-II of extant Accipitridae (hawks and eagles; one family of the birds commonly known as “raptors”). Here, the talon is used to maintain grip on prey of subequal body size to the predator, while the victim is pinned down by the body weight of the raptor and dismembered by the beak. The foot of Deinonychus exhibits morphology consistent with a grasping function, supportive of the prey immobilisation behavior model. Opposite morphological trends within Deinonychosauria (Dromaeosauridae + Troodontidae) are indicative of ecological separation. Placed in context of avian evolution, the grasping foot of Deinonychus and other terrestrial predatory paravians is hypothesized to have been an exaptation for the grasping foot of arboreal perching birds. Here we also describe “stability flapping”, a novel behaviour executed for positioning and stability during the initial stages of prey immobilisation, which may have been pivotal to the evolution of the flapping stroke. These findings overhaul our perception of predatory dinosaurs and highlight the role of exaptation in the evolution of novel structures and behaviours.

- by Denver Fowler
- •
- Geology, Paleontology, Biomechanics, Functional Morphology
- by Richard L. Cifelli
- •
- Evolutionary Biology, Geology, Paleontology, Computed Tomography

Стегозавры (Dinosauria; Ornithischia) были широко распространены во множестве
наземных фаун с середины юрского периода и до конца мелового, и играют большую
роль в понимании эволюции динозавров и палеобиогеографического распределения.
Таксон Eurypoda является неуместным по причине спорных отличительных признаков
разных групп. Даны краткие и предварительные характеристики новых таксонов и
рассмотрены вопросы эволюции группы в целом. Многие североамериканские и
европейские ископаемые останки стегозавров должны быть ревизованы и заново
описаны на основе современных данных и сравнения с новыми находками. Большое
разнообразие азиатских, европейских и североамериканских стегозавров в конце
юрского периода говорит о благоприятных условиях существования для этой группы
в данный промежуток времени. Вместе с тем, многие представители стегозаврид
приспособились к довольно сложным условиям некоторых сред обитания.

- by Roman Ulansky
- •
- Dinosaurian Paleontology, Dinosauria, Dinosaurian Evolution, Dinosaurian Phylogeny
- by David Eliseo Rubilar Rogers and +6
- •
- Dinosaur Paleontology, Dinosaurian Paleontology, Dinosauria, Dinosaurs

Carcharodontosaurs were the largest predatory dinosaurs, and their early evolutionary history seems to be more intricate than was previously thought. Until recently, carcharodontosaurs were restricted to a group of large theropods inhabiting the Late Cretaceous Gondwanan land masses, but in the last few years Laurasian evidence has been causing a reevaluation of their initial diversification. Here we describe an almost complete and exquisitely preserved skeleton of a medium-sized (roughly six metres long) theropod from the Lower Cretaceous series (Barremian stage) Konservat-Lagerstätte of Las Hoyas in Cuenca, Spain. Cladistic analysis supports the idea that the new taxon Concavenator corcovatus is a primitive member of Carcharodontosauria, exhibiting two unusual features: elongation of the neurapophyses of two presacral vertebrae forming a pointed, hump-like structure and a series of small bumps on the ulna. We think that these bumps are homologous to quill knobs present on some modern birds; the knobs are related to the insertion area of follicular ligaments that anchor the roots of the flight feathers (remiges) to the arm. We propose that Concavenator has integumentary follicular structures inserted on the ulna, as in modern birds. Because scales do not have follicles, we consider the structures anchored to the Concavenator arms to be non-scale skin appendages homologous to the feathers of modern birds. If this is true, then the phylogenetic bracket for the presence of non-scale skin structures homologous to feathers in theropod dinosaurs would be extended to the Neotetanurae, enlarging the scope for explaining the origin of feathers in theropods.

- by Fernando Escaso
- •
- Morphology, Evolution, Palaeontology, Multidisciplinary

- by Adrian Hunt and +2
- •
- Evolutionary Biology, Paleobiology, Geology, Stratigraphy

- by Jose Ruben Guzman-Gutierrez
- •
- Paleobiology, Geology, Vertebrate Palaeontology, Dental microwear

Here we report new hadrosaur remains recovered from the Cerro del Pueblo Formation (Upper Cretaceous: Campanian) at La Parrita
locality, northeastern Mexico. Although the material is fragmentary, the identification of dental microwear in three out of the four teeth
collected is notable. This sample allows for a preliminary assessment of hadrosaur dental microwear from this geographic region and
time frame. The variables studied were the orientation and average count of scratches, average count of pits, and average microwear
feature width in an area of 400 X 400 μm at 35X magnification. The results show a predominance of dorsodistally-ventromesially
inclined scratches in all three teeth indicating that the mandible primarily moved in an orthopalinal direction during the power stroke.
The pattern of scratch orientation we recorded is comparable to that reported for different hadrosaur species from Alberta, Canada,
and Wyoming, U.S.A.; suggesting similar jaw mechanics in the hadrosaurs from Coahuila. In contrast, there are significant differences
in the average number of pits and microwear feature width between the Alberta and the Coahuila hadrosaurs samples, with the latter
presenting more pits and finer microwear features. Given the similar jaw mechanics between the Alberta and Coahuila hadrosaurs,
suggested by our analysis, the difference in average number of pits and microwear feature width is probably due to differences in diet
and/or the type and amount of grit ingested during feeding. The greater number of pits in the hadrosaurs from Coahuila might indicate
that these individuals ingested a greater proportion of hard food items than the Alberta hadrosaurs.

Chungkingosaurus (Dong, Zhou, and Zhang, 1983) – род китайских
верхнеюрских бронированных растительноядных динозавров из
инфраотряда Stegosauria. Название рода дано по месту находки, города
Chungqing (или Chungking), где в 1977 году были обнаружены кости.
Chungkingosaurus сосуществовал одновременно с несколькими другими
видами стегозавров, обитавших на территории современной провинции
Сычуань. Найденные недалеко друг от друга несколько экземпляров
Chungkingosaurus, по предположению авторов, непосредственно изучавших
материал (Dong, Zhou, and Zhang, 1983; Dong, 1990), могли представлять, по
меньшей мере, разные виды рода Chungkingosaurus, но этому мешал
слишком фрагментарный материал. Кроме типового вида с единственным
экземпляром скелета известно также три других отличительных
индивидуума, но фрагментарность останков позволяет провести сравнение
на основании лишь отдельных сопоставимых элементов скелета. Это кости
таза, бедра, плечевые кости и некоторые другие.

- by Roman Ulansky
- •
- Dinosauria, Stegosauria

В 1983 году в верхнеюрских отложениях провинции Сычуань в Китае
экспедицией под руководством Wan Jihou был выкопан скелет небольшого
стегозавра. Впервые имя этого стегозавра, Yingshanosaurus, упоминается в
1984 году в монографической статье Жоу (Zhou, 1984) с описанием
среднеюрского примитивного стегозавра Huayangosaurus. Какое либо
описание нового рода в данной работе отсутствовало, но автор представил
графические рисунки крестца и кожной пластины. В 1985 году также Жоу
(Zhou, 1985) использовал имя Yingshanosaurus jichuanensis во время
палеонтологического конгресса в Тулузе. Не смотря на то, что его лекция
была опубликовано в 1986 году, название оставалось nomen nudum из-за
недостаточного описания и отсутствия определения типового экземпляра.
Полное описание животного было опубликовано С. Жу (Zhu, 1994), на
китайском языке. По этой причине описание оставалось совершенно
незамеченным большинством палеонтологов за пределами Китая на
протяжении 20 лет.

- by Roman Ulansky
- •
- Dinosauria, Stegosauria, Dinosaur Anatomy
- by Roberto Díaz-Sibaja
- •
- Educación, Dinosauria, Dinosaurs, Divulgación Científica
- by Peter Galton and +1
- •
- Evolutionary Biology, Geology, Ecology, Vertebrate Paleontology

Postcranial skeletal pneumaticity (PSP) is a condition most notably found in birds, but that
is also present in other saurischian dinosaurs and pterosaurs. In birds, skeletal pneumatization
occurs where bones are penetrated by pneumatic diverticula, membranous extensions
that originate from air sacs that serve in the ventilation of the lung. Key questions that
remain to be addressed include further characterizing (1) the skeletal features that can be
used to infer the presence/absence and extent of PSP in birds and non-avian dinosaurs,
and (2) the association between vertebral laminae and specific components of the avian
respiratory system. Previous work has used vertebral features such as pneumatic foramina,
fossae, and laminae to identify/infer the presence of air sacs and diverticula, and to discuss
the range of possible functions of such features. Here, we tabulate pneumatic features in
the vertebral column of 11 avian taxa, including the flightless ratites and selected members
of semi-volant and semi-aquatic Neornithes. We investigate the associations of these osteological
features with each other and, in the case of Struthio camelus, with the specific presence
of pneumatic diverticula. We find that the mere presence of vertebral laminae does not
indicate the presence of skeletal pneumaticity, since laminae are not always associated
with pneumatic foramina or fossae. Nevertheless, laminae are more strongly developed
when adjacent to foramina or fossae. In addition, membranous air sac extensions and adjacent
musculature share the same attachment points on the vertebrae, rendering the use of
such features for reconstructing respiratory soft tissue features ambiguous. Finally, pneumatic
diverticula attach to the margins of laminae, foramina, and/or fossae prior to their
intraosseous course. Similarities in PSP distribution among the examined taxa are concordant
with their phylogenetic interrelationships. The possible functions of PSP are discussed
in brief, based upon variation in the extent of PSP between taxa with differing ecologies.

- by Naomi E Apostolaki and +1
- •
- Dinosaur Paleontology, Ornithischians, Dinosauria, Dinosaurs
- by Felipe Montenegro
- •
- Uruguay, Dinosauria, Sauropods, Titanosaur Sauropods

Assessments of dinosaur macroevolution at any given time can be biased by the historical publication record. Recent studies have analysed patterns in dinosaur diversity that are based on secular variations in the numbers of published taxa. Many of these have employed a range of approaches that account for changes in the shape of the taxonomic abundance curve, which are largely dependent on databases compiled from the primary published literature. However, how these 'corrected' diversity patterns are influenced by the history of publication remains largely unknown. Here, we investigate the influence of publication history between 1991 and 2015 on our understanding of dinosaur evolution using raw diversity estimates and shareholder quorum subsampling for the three major subgroups: Ornithischia, Sauropodomorpha, and Theropoda. We find that, while sampling generally improves through time, there remain periods and regions in dinosaur evolutionary history where diversity estimates are highly volatile (e.g. the latest Jurassic of Europe, the mid-Cretaceous of North America, and the Late Cretaceous of South America). Our results show that historical changes in database compilation can often substantially influence our interpretations of dinosaur diversity. 'Global' estimates of diversity based on the fossil record are often also based on incomplete, and distinct regional signals, each subject to their own sampling history. Changes in the record of taxon abundance distribution, either through discovery of new taxa or addition of existing taxa to improve sampling evenness, are important in improving the reliability of our interpretations of dinosaur diversity. Furthermore, the number of occurrences and newly identified dinosaurs is still rapidly increasing through time, suggesting that it is entirely possible for much of what we know about dinosaurs at the present to change within the next 20 years.

- by Matthew Baron
- •
- Diversity, Life history, Evolution, Dinosaur Paleontology
- by Fernando Escaso
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- Morphology, Evolution, Palaeontology, Multidisciplinary

It has become accepted in recent years that the fossil record can preserve labile tissues. We report here the highly detailed mineralization of soft tissues associated with a naturally occurring brain endocast of an iguanodontian dinosaur found in c. 133 Ma fluvial sediments of the Weal-den at Bexhill, Sussex, UK. Moulding of the braincase wall and the mineral replacement of the adjacent brain tissues by phosphates and carbonates allowed the direct examination of petrified brain tissues. Scanning electron microscopy (SEM) imaging and computed tomography (CT) scanning revealed preservation of the tough membranes (meninges) that enveloped and supported the brain proper. Collagen strands of the meningeal layers were preserved in collophane. The blood vessels , also preserved in collophane, were either lined by, or infilled with, microcrystalline siderite. The meninges were preserved in the hindbrain region and exhibit structural similarities with those of living archosaurs. Greater definition of the forebrain (cerebrum) than the hindbrain (cere-bellar and medullary regions) is consistent with the anatomical and implied behavioural complexity previously described in iguanodontian-grade ornithopods. However, we caution that the observed proximity of probable cortical layers to the braincase walls probably resulted from the settling of brain tissues against the roof of the braincase after inversion of the skull during decay and burial.

- by khaled magdy
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- Paleobiology, Paleontology, Vertebrate Paleontology, Dinosaur Paleontology

In a recent article in this journal, Fassett (2009) concludes that dinosaur fossils of Paleocene age are present in the San Juan Basin of New Mexico-Colorado. However, we argue that, based on existing data, Fassett has failed to produce compelling evidence to support this conclusion. In the San Juan Basin, only one arguably reworked dinosaur bone (an isolated hadrosaur femur) is stratigraphically above undisputed Paleocene pollen, so palynology does not demonstrate Paleocene dinosaurs in the San Juan Basin. Nor does magnetostratigraphy, because Fassett’s disregard of a major unconformity above the dinosaur-bearing Naashoibito Member renders questionable his use of an uninterrupted magnetostratigraphy to assign a Paleocene age to dinosaur fossils in that unit. Moreover, Fassett’s article failed to adequately dismiss the broadly held conclusions that: (1) the Cretaceous-Tertiary boundary is within the Ojo Alamo Sandstone; (2) the dinosaur-dominated vertebrate fossil assemblage of the lower Ojo Alamo Sandstone (Alamo Wash local fauna of the Naashoibito Member) is of Maastrichtian age; and (3) the isolated, water-worn and/or fragmentary dinosaur bones from the overlying Kimbeto Member are reworked from underlying Cretaceous strata.

- by Denver Fowler
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- Paleobiology, Stratigraphy, Biostratigraphy, Evolution

Wedel, M.J., Cifelli, R.L., & Sanders, R.K. 2000. Osteology, paleobiology, and relationships of the sauropod dinosaur Sauroposeidon. -Acta Palaeontologica Polonica 45,4, 343-388. Sauroposeidon proteles is a large brachiosaurid sauropod recently described from the Antlers Formation (Aptian-Albian) of southeastern Oklahoma. Sauroposeidon represents the culmination of brachiosaurid trends toward lengthening and lightening the neck, and its cervical vertebrae are characterized by extensive pneumatic structures. The elaboration of vertebral air sacs during sauropod evolution produced a variety of internal structure types. We propose anew classification system for this array of vertebral characters, using computed tomography (CT) of pneumatic internal structures. Comparisons with birds suggest that the vertebrae of sauropods were pneumatized by a complex system of air sacs in the thorax and abdomen. The presence of a thoraco-abdominal air sac system in sauropods would dramatically affect ...

- by Kent Sanders
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- Evolutionary Biology, Geology, Paleontology, Computed Tomography

THE Lower Cretaceous lithographic limestones from Las Hoyas (province of Cuenca, Spain) have yielded important vertebrate fossil remains. We report here a new specimen, the first ornithomimosaur theropod found in Europe. Pelecanimimus polyodon gen. et sp. nov., has some striking elements preserved, such as the hyoid, sternum and integumentary impressions. The fossil has revealed other unexpected features, including a derived hand in an ancient ornithomimosaur, and a large number of teeth (over 200) with a distinctive morphology. This specimen suggests an alternative evolutionary process towards the toothless condition in Ornithomi-mosauria, which could be explained by an exaptation. Pelecanimimus polyodon stresses the relationship between Troodontidae and Ornithomimosauria.

- by Francisco Ortega
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- Spain, Theropoda, Dinosauria, Cretaceous
- by Ricardo N. Martínez
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- Sedimentology, Stratigraphy, Dinosauria, Lower Jurassic

A new sauropod from the Middle Jurassic of Niger, Spinophorosaurus nigerensis n. gen. et sp., is the most complete basal sauropod currently known. The taxon shares many anatomical characters with Middle Jurassic East Asian sauropods,... more

- by Francisco Ortega
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- Africa, Niger, Jurassic, Dinosauria
- by Walter Stein
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- Dinosaur Paleontology, Dinosauria, Dinosaurs, Fossils

New material of the rare ankylosaurid dinosaur Nodocephalosaurus kirtlandensis Sullivan, 1999 is identified and described. Specimens include cephalic osteoderms, a cervical spine, and two caudal vertebrae. The caudal vertebrae are distinct from other known North American ankylosaurids (such as Euoplocephalus tutus), thus reinforcing their taxonomic assignment to N. kirtlandensis. Presently, N. kirtlandensis is known only from the De-na-zin Member of the Kirtland Formation, San Juan Basin, New Mexico.

- by Denver Fowler
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- Geology, Paleontology, Paleoecology, Taphonomy

Dinosaurs dominated Mesozoic terrestrial ecosystems globally. However, whereas a pole-to-pole geographic distribution characterized ornithischians and theropods, sauropods were restricted to lower latitudes. Here, we evaluate the role of climate in shaping these biogeographic patterns through the Jurassic–Cretaceous (201–66 mya), combining dinosaur fossil occurrences, past climate data from Earth System models, and habitat suitability modeling. Results show that, uniquely among dinosaurs, sauropods occupied climatic niches characterized by high temperatures and strongly bounded by minimum cold temperatures. This constrained the distribution and dispersal pathways of sauropods to tropical areas, excluding them from latitudinal extremes, especially in the Northern Hemisphere. The greater availability of suitable habitat in the southern continents, particularly in the Late Cretaceous, might be key to explaining the high diversity of sauropods there, relative to northern landmasses. Given that ornithischians and theropods show a flattened or bimodal latitudinal biodiversity gradient, with peaks at higher latitudes, the closer correspondence of sauropods to a subtropical concentration could hint at fundamental thermophysiological differences to the other two clades.

- by Alfio Alessandro Chiarenza
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- Climate Change, Ecology, Biogeography, Dinosaur Paleontology