Evidence of Parasites in Hadrosaurs From Campanian Cretaceous Canada

Trace fossils of possible parasites inside the gut contents of a hadrosaurid dinosaur, Upper Cretaceous Judith River Formation, Montana

Authors:

Tweet et al

Abstract:

Tiny sinuous trace fossils have been found within probable gut contents of an exceptionally preserved specimen of a hadrosaurid dinosaur, Brachylophosaurus canadensis, from the Judith River Formation of Montana. Approximately 280 examples of the trace fossils were observed in 19 samples of gut region material. The tubular structures typically are about 0.3 mm across. Many have thin calcareous linings or layers, and some exhibit fine surficial striae. At least two dozen of these trace fossils share walls with adjacent tubular traces, and this association can extend for several millimeters. While the trace fossils share some characteristics with fine rhizoliths, these features are most consistent with tiny burrows, or possibly body impressions, of worms (vermiform organisms) of uncertain biologic affinity. Such trace fossils have not been reported previously, and herein described as Parvitubulites striatus n. gen. n. sp. Either autochthonous (parasites) or allochthonous (scavengers) worms may have created the trace fossils, but taphonomic factors suggest that autochthonous burrowers are more likely. Several lines of evidence, such as constant diameters and matching directional changes, suggest that the paired trace fossils were made by two individuals moving at the same time, which implies sustained intraspecific contact. Parvitubulites striatus provides a rare record of interactions between terrestrial, meiofaunal-sized, soft-bodied invertebrates and a dinosaur carcass. The evidence that the worms may have parasitized a living hadrosaur and subsequently left traces of intraspecific behavior between individual worms adds unique information to our understanding of Mesozoic trophic interactions.

Blood Vessels From Campanian Cretaceous Hadrosaur Brachylophosaurus canadensis Confirmed

Researchers from North Carolina State University have confirmed that blood vessel-like structures found in an 80 million-year-old hadrosaur fossil are original to the animal, and not biofilm or other contaminants. Their findings add to the growing body of evidence that structures like blood vessels and cells can persist over millions of years, and the data not only confirm earlier reports of protein sequences in dinosaurs, they represent a significant advance in methodology.

Molecular paleontologist Tim Cleland, currently a postdoctoral researcher at the University of Texas at Austin, began the work while a graduate student at NC State. He demineralized a piece of leg bone from a Brachylophosaurus canadensis, a 30-foot-long hadrosaur that roamed what is now Montana around 80 million years ago. Cleland analyzed the demineralized bone with high resolution mass spectroscopy and found several distinct proteins from the cellular components of the blood vessels. One of these proteins, myosin, is found in the smooth muscles associated with the walls of blood vessels.

link.

Very Complete Hatchling Hadrosaur Saurolophus angustirostris Found From Upper Cretaceous Mongolia

Perinatal Specimens of Saurolophus angustirostris (Dinosauria: Hadrosauridae), from the Upper Cretaceous of Mongolia

Authors:

Dewaele et al

Abstract:

Background

The Late Cretaceous Nemegt Formation, Gobi Desert, Mongolia has already yielded abundant and complete skeletons of the hadrosaur Saurolophus angustirostris, from half-grown to adult individuals.

Methodology/Principal Findings

Herein we describe perinatal specimens of Saurolophus angustirostris, associated with fragmentary eggshell fragments. The skull length of these babies is around 5% that of the largest known S. angustirostris specimens, so these specimens document the earliest development stages of this giant hadrosaur and bridge a large hiatus in our knowledge of the ontogeny of S. angustirostris.

Conclusions/Significance

The studied specimens are likely part of a nest originally located on a riverbank point bar. The perinatal specimens were buried by sediment carried by the river current presumably during the wet summer season. Perinatal bones already displayed diagnostic characters for Saurolophus angustirostris, including premaxillae with a strongly reflected oral margin and upturned premaxillary body in lateral aspect. The absence of a supracranial crest and unfused halves of the cervical neural arches characterize the earliest stages in the ontogeny of S. angustirostris. The eggshell fragments associated with the perinatal individuals can be referred to the Spheroolithus oogenus and closely resemble those found in older formations (e.g. Barun Goyot Fm in Mongolia) or associated with more basal hadrosauroids (Bactrosaurus-Gilmoreosaurus in the Iren Dabasu Fm, Inner Mongolia, China). This observation suggests that the egg microstructure was similar in basal hadrosauroids and more advanced saurolophines.

Competing Interests

One of the authors (FE) is employed by the commercial organization Eldonia. Eldonia provided support in the form of a salary for FE, but did not have any additional role or influence in the study design, data collection and analysis, decision to publish, or preparation of the manuscript and it does not alter the authors’ adherence to all the PLoS ONE policies on sharing data and materials.

Late Cretaceous Hadrosaurs Confirmed to Herd

Herd structure in Late Cretaceous polar dinosaurs: A remarkable new dinosaur tracksite, Denali National Park, Alaska, USA

Authors:

Fiorillo et al

Abstract:

The discovery of a new tracksite of mostly hadrosaurid dinosaur footprints, made by a herd living in an ancient high-latitude continental ecosystem, provides insight into the herd structure and behavior of northern polar dinosaurs and perspective on populations of large-bodied herbivores in an Arctic greenhouse world. This tracksite occurs in the Upper Cretaceous Cantwell Formation in the Alaska Range (Denali National Park, Alaska, United States), and it is the largest tracksite known from this far north. Preservation of the tracksite is exceptional: most tracks, regardless of size, contain skin impressions and they co-occur with well-preserved plant fossils and invertebrate trace fossils of terrestrial and aquatic insects. Statistical analyses of the tracks show that individuals of four different age classes of hadrosaurids lived together in a large social group. Our research results independently corroborate the growth curve for hadrosaurids proposed by paleohistologists that suggests that these dinosaurs experienced a period of rapid growth early in their life history.

An AMAZING Juvenile Edmontosaurus from Late Maastrichtian Cretaceous North America

A juvenile Edmontosaurus from the late Maastrichtian (Cretaceous) of North America: Implications for ontogeny and phylogenetic inference in saurolophine dinosaurs

Author:

Prieto-Márquez

Abstract:

The anatomy of an articulated juvenile specimen of the saurolophine hadrosaurid dinosaur Edmontosaurus annectens, LACM 23504, is described in detail. This individual consists of a partial skull and nearly complete articulated postcranium, collected from upper Maastrichtian strata of the Hell Creek Formation of Montana, USA. This study aims to help understand the ontogenetic morphological changes occurring in the cranium and postcranium of saurolophine hadrosaurids using E. annectens as a case study. Emphasis is placed on those morphological attributes that are ontogenetically variable via comparative osteology between the juvenile and the available adult specimens. It is observed that much of the cranial ontogenetic variation relates to the elongation of the skull and mandible. In the postcranium, most of the ontogenetic variation concentrates in the pectoral and pelvic girdles and the stylopodia. Not all the identified patterns of ontogenetic variation may be generalized to all hadrosaurids. The impact of ontogenetic variation on phylogenetically informative characters of saurolophine hadrosaurids is evaluated. It is concluded that, at least for Edmontosaurus annectens (and perhaps other saurolophine hadrosaurids), most characters used in phylogenetic inference of these animals are not affected by ontogeny. Thus, juvenile specimens are still a source of substantial character data suitable for use in phylogenetic analyses of saurolophine relationships. Nevertheless, it is recommended that ontogenetically variable characters are left as missing data in a character–taxon matrix when only juvenile material is available for a given saurolophine taxon. Scoring those characters based solely on juveniles is likely to decrease the accuracy of the phylogenetic inference.

Hadrosaur Vertebra Found in Arctic Campanian Cretaceous Nunavut, Canada

A Hadrosaurid (Dinosauria: Ornithischia) from the Late Cretaceous (Campanian) Kanguk Formation of Axel Heiberg Island, Nunavut, Canada, and Its Ecological and Geographical Implications

Authors:

Vavrek et al

Abstract:

A hadrosaurid vertebra was recovered during a palynological survey of the Upper Cretaceous Kanguk Formation in the eastern Canadian Arctic. This vertebra represents the farthest north record of any non-avian dinosaur to date. Although highly abraded, the fossil nonetheless represents an interesting biogeographic data point. During the Campanian, when this vertebra was deposited, the eastern Canadian Arctic was likely isolated both from western North America by the Western Interior Seaway and from more southern regions of eastern North America by the Hudson Seaway. This fossil suggests that large-bodied hadrosaurid dinosaurs may have inhabited a large polar insular landmass during the Late Cretaceous, where they would have lived year-round, unable to migrate to more southern regions during winters. It is possible that the resident herbivorous dinosaurs could have fed on non-deciduous conifers, as well as other woody twigs and stems, during the long, dark winter months when most deciduous plant species had lost their leaves.

Edmontosauraus regalis: The Duck-billed Dinosaur who Sported a Chicken's Crest

A rare, mummified specimen of the duck-billed dinosaur Edmontosauraus regalis described in the Cell Press journal Current Biology on December 12 shows for the first time that those dinosaurs' heads were adorned with a fleshy comb, most similar to the roosters' red crest.

The most common dinosaurs in North America between 75 and 65 million years ago, duck-billed dinosaurs were gentle giants, about 12 meters long, and filled the same ecological role that kangaroos or deer play today. But no one had suspected that they—or other dinosaurs, for that matter—had fleshy structures on the tops of their heads.

"Until now, there has been no evidence for bizarre soft-tissue display structures among dinosaurs; these findings dramatically alter our perception of the appearance and behavior of this well-known dinosaur and allow us to comment on the evolution of head crests in this group," says Phil Bell from Australia's University of New England. "It also raises the thought-provoking possibility of similar crests among other dinosaurs."

The dinosaur specimen in question was found in deposits west of the city of Grande Prairie in west-central Alberta, Canada. Bell, along with Federico Fanti from the University of Bologna, Italy, knew they had something special when they found skin impressions on parts of the mummified body. But it wasn't until Bell put a chisel through the top of the crest that he realized they really had something incredible.

"An elephant's trunk or a rooster's crest might never fossilize because there's no bone in them," Bell explains. "This is equivalent to discovering for the first time that elephants had trunks. We have lots of skulls of Edmontosaurus, but there are no clues on them that suggest they might have had a big fleshy crest. There's no reason that other strange fleshy structures couldn't have been present on a whole range of other dinosaurs, including T. rex or Triceratops."

Of course, it's hard to tell what that cocks comb might have done for the duck-billed dinosaurs. In roosters and some other birds, bright red crests are a way to get the girls. "We might imagine a pair of male Edmontosaurus sizing each other up, bellowing, and showing off their head gear to see who was the dominant male and who is in charge of the herd," Bell says.

link.

Tsintaosaurus: The ‘Unicorn’ Dinosaur That Wasn’t

The ‘Unicorn’ Dinosaur That Wasn’t: A New Reconstruction of the Crest of Tsintaosaurus and the Early Evolution of the Lambeosaurine Crest and Rostrum

Authors:

Albert Prieto-Márquez and Jonathan R. Wagner

Abstract:

The lambeosaurine Tsintaosaurus spinorhinus has traditionally been reconstructed with an elevated, hollow, spike-like crest composed entirely of the nasal bones, although this has been disputed. Here, we provide a new reconstruction of the skull of this species based on reexamination and reinterpretation of the morphology and articular relationships of the type and Paratype skulls and a fragmentary crest. We confirm the presence of a supracranial crest composed of the elevated nasal bones, but also including the premaxillae. We hypothesize that the crest is a tall, lobate, hollow structure that projects dorsally and slightly caudally a distance greater than the height of the skull along the quadrate. In our reconstruction, the nasal passage passes through the crest, but enters the skull rostral to the tubular process of the nasals, not through it. Tsintaosaurus spinorhinus is rediagnosed on the basis of a suite of cranial autapomorphies including a circumnarial fossa subdivided into three accessory fossae, prefrontal with ascending rostral process and lateral flange, nasals fused sagittally to form elongate tubular process that rises dorsally from skull roof, each nasal being expanded rostrocaudally into a rhomboid distal process, and medial processes of premaxillae at the summit of the cranial crest inserted between rhomboid processes of nasals. Tsintaosaurus spinorhinus lacks characters that are present in more derived lambeosaurines (parasaurolophins and lambeosaurins), such as rotation of the caudal margin of the crest to an acute angle with the skull roof, lateral processes of the nasals that enclose part of the intracranial cavity and participate in the formation of the walls of the common median chamber, and a smooth narial fossa lacking ridges and accessory fossae. We hypothesize that ancestrally the rostrum of lambeosaurines may have been more similar to that in Saurolophinae, and became subsequently reduced in complexity during evolution of the group.

High School Kid Finds Joe the Parasaurolophus

A chance find by a high school student led to the youngest, smallest and most complete fossil skeleton yet known from the iconic tube-crested dinosaur Parasaurolophus. The discovery, announced today by the Raymond M. Alf Museum of Paleontology at The Webb Schools, shows that the prehistoric plant-eater sprouted its strange headgear before it celebrated its first birthday. Three-dimensional scans of nearly the entire fossil are freely available online, making this the most digitally-accessible dinosaur to date.

The fossil skeleton was discovered in 2009 by high school student Kevin Terris, within Grand Staircase-Escalante National Monument in southern Utah. Incredibly, the specimen was missed by two professional paleontologists, who walked within several feet of the exposed bones days prior to the discovery. "At first I was interested in seeing what the initial piece of bone sticking out of the rock was," commented Terris. "When we exposed the skull, I was ecstatic!" Excavation and subsequent cleaning of the fossil, nicknamed "Joe" after a long-time supporter of the Alf Museum whose family funded preparation of the fossil, revealed nearly the entire skeleton of a baby dinosaur measuring only six feet long when it died.

Detailed study of the skeleton of "Joe" identified it as the most complete specimen yet known for Parasaurolophus (pronounced PAIR-uh-SORE-AH-luf-us), a duck-billed (hadrosaurid) dinosaur that lived throughout western North America around 75 million years ago. The herbivore is notable for a long and hollow bony tube on the top of its skull, which scientists speculate was used like a trumpet to blast sound for communication, as well as a billboard for visual display. Although partial skulls and skeletons of full-grown Parasaurolophus have been known for over 90 years, scientists previously knew little about how Parasaurolophus grew up.

link. paper link.  SVOtW write up.

Lambeosaurine Hadrosaur Dinosaurs Spread into the European Archipelago From Asia?

Diversity, Relationships, and Biogeography of the Lambeosaurine Dinosaurs from the European Archipelago, with Description of the New Aralosaurin Canardia garonnensis

Authors:

1. Albert Prieto-Márquez
2. Fabio M. Dalla Vecchia
3. Rodrigo Gaete,
4. Àngel Galobart

Affiliations:

a. Bayerische Staatssammlung für Paläontologie und Geologie, Munich, Germany

b. Grup de Recerca del Mesozoic, Institut Català de Paleontologia Miquel Crusafont, Sabadell, Spain

c. Museu de la Conca Dellà, Isona, Spain

Abstract:

We provide a thorough re-evaluation of the taxonomic diversity, phylogenetic relationships, and historical biogeography of the lambeosaurine hadrosaurids from the European Archipelago. Previously published occurrences of European Lambeosaurinae are reviewed and new specimens collected from upper Maastrichtian strata of the south-central Pyrenees are described. No support is found for the recognition of European saurolophines in the available hadrosaurid materials recovered so far from this area. A new genus and species of basal lambeosaurine, Canardia garonnensis, is described on the basis of cranial and appendicular elements collected from upper Maastrichtian strata of southern France. C. garonnensis differs from all other hadrosaurids, except Aralosaurus tuberiferus, in having maxilla with prominent subrectangular rostrodorsal flange; it differs from A. tuberiferus in a few maxillary and prefrontal characters. Together with A. tuberiferus, C. garonnensis integrates the newly recognized tribe Aralosaurini. Inference of lambeosaurine interrelationships via maximum parsimony analysis indicates that the other three known European lambeosaurines are representatives of two additional subclades (tribes) of these hadrosaurids: Tsintaosaurini (Pararhabdodon isonensis) and Lambeosaurini (the Arenysaurus ardevoli-Blasisaurus canudoi clade). The tribes Aralosaurini, Tsintaosaurini, Lambeosaurini, and Parasaurolophini are formally defined and diagnosed for the first time. Three event-based quantitative methods of ancestral range reconstruction were implemented to infer the historical biogeography of European lambeosaurines: Dispersal-Vicariance Analysis, Bayesian Binary MCMC, and Dispersal-Extinction-Cladogenesis. The results of these analyses, coupled with the absence of pre-Maastrichtian lambeosaurines in the Mesozoic vertebrate fossil record of Europe, favor the hypothesis that aralosaurins and tsintaosaurins were Asian immigrants that reached the Ibero-Armorican island via dispersal events sometime during the Maastrichtian. Less conclusive is the biogeographical history of European lambeosaurins; several scenarios, occurring sometime during the Maastrichtian, are possible, from vicariance leading to the splitting of Asian or North American from European ranges to a dispersal event from North America to the European Archipelago.

Hardrosaur Trackways From the Late Maastrichtian Bolster Bollide Impact Extinction for KT/K-Pg Extinction

The Latest Succession of Dinosaur Tracksites in Europe: Hadrosaur Ichnology, Track Production and Palaeoenvironments

Authors:

1. Bernat Vila (a,b)
2. Oriol Oms (c)
3. Víctor Fondevilla (c)
4. Rodrigo Gaete (d)
5. Àngel Galobart (b)
6. Violeta Riera (c)
7. José Ignacio Canudo (a)

Affiliations:

a. Grupo Aragosaurus–IUCA, Paleontología, Facultad de Ciencias Universidad de Zaragoza, Zaragoza, Spain

b. Institut Català de Paleontologia Miquel Crusafont, Sabadell, Barcelona, Spain

c. Departament de Geologia (Estratigrafia), Facultat de Ciències Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain

d. Museu de la Conca Dellà, Isona i Conca Dellà, Lleida, Spain

Abstract:

A comprehensive review and study of the rich dinosaur track record of the Tremp Formation in the southern Pyrenees of Spain (Southwestern Europe) shows a unique succession of footprint localities prior to the end-Cretaceous mass extinction event. A description of some 30 new tracksites and data on sedimentary environments, track occurrence and preservation, ichnology and chronostratigraphy are provided. These new track localities represent various facies types within a diverse set of fluvial environments. The footprint discoveries mostly represent hadrosaurian and, less abundantly, to sauropod dinosaurs. The hadrosaur tracks are significantly smaller in size than, but morphologically similar to, those of North America and Asia and are attributable to the ichnogenus Hadrosauropodus. The track succession, with more than 40 distinct track levels, indicates that hadrosaur footprints in the Ibero-Armorican region occur predominantly in the late Maaastrichtian (at least above the early Maastrichtian–late Maastrichtian boundary). The highest abundance is found noticeably found in the late Maastrichtian, with tracks occurring in the C29r magnetochron, within about the latest 300,000 years of the Cretaceous.

paper link.

Brian's pop sci short write up.

Hadrosaurs Had Excellent Chewing Apparatus

A team of paleontologists and engineers has found that duck-billed dinosaurs had an amazing capacity to chew tough and abrasive plants with grinding teeth more complex than those of cows, horses, and other well-known modern grazers. Their study, which is published today in the journal Science, is the first to recover material properties from fossilized teeth.

Duck-bill dinosaurs, also known as hadrosaurids, were the dominant plant-eaters in what are now Europe, North America, and Asia during the Late Cretaceous about 85 million years ago. With broad jaws bearing as many as 1,400 teeth, hadrosaurids were previously thought to have chewing surfaces similar to other reptiles, which have teeth comprised of just two tissues—enamel, a hard hypermineralized material, and orthodentine, a soft bonelike tissue. But paleontologists who study the fossilized teeth of these animals in detail suspected that they were not that simple.

"We thought for a long time that there was more going on because you could just look at the surface of the tooth and see advanced topography, which suggests that there are many different tissues present," said Mark Norell, chair of the American Museum of Natural History's Division of Paleontology and an author on the paper.

To investigate the dinosaurs' dental structure and properties in depth, Norell worked with lead author Gregory Erickson, a biology professor at Florida State University, and a team of engineers on a series of novel experiments. Erickson sectioned the fossilized teeth and made microscope slides from them. These revealed that hadrosaurids actually had six different types of dental tissues—four more than reptiles and two more than expert mammal grinders like horses, cows, and elephants. Using a technique called nanoindentation, in which a diamond-tipped probe is indented and/or drawn across the fossilized teeth to mimic the grinding of abrasive food, the researchers determined the differential hardness and wear rates of the dental tissues.

Erickson, who describes hadrosaurid dinosaurs as "walking pulp mills," said, "We were stunned to find that the mechanical properties of the teeth were preserved after 70 million years of fossilization." He went on to comment that "if you put these teeth back into a living dinosaur they would function perfectly."

In addition to the four dental tissues found in mammals—enamel, orthodentine, secondary dentine that helps prevent cavities, and coronal cementum that supports the teeth's crests—the hadrosaurid teeth include giant tubules and a thick mantle dentine. These extra tissues are thought to provide additional prevention against abscesses. Also unlike mammalian teeth, the dental tissue distribution in hadrosaurids greatly varied in each tooth.

Together, these characteristics suggest that hadrosaurids evolved the most advanced grinding capacity known in vertebrate animals, which might have led to their extensive diversification.

"Duck-bills' advanced tissue modification appears to have allowed them to radiate into specialized ecological niches where they ate extremely tough plants like fern, horsetail, and ground cover that were not as easy for dinosaurs with shearing teeth to eat," Norell said. "Their complex dentition could have played a major role in keeping them on the planet for nearly 35 million years."

Alaskan Hadrosaurs Stayed Through the Winter

Duck-billed dinosaurs that lived within Arctic latitudes approximately 70 million years ago likely endured long, dark polar winters instead of migrating to more southern latitudes, a recent study by researchers from the University of Cape Town, Museum of Nature and Science in Dallas and Temple University has found.

The researchers published their findings, "Hadrosaurs Were Perennial Polar Residents," in the April issue of the journal The Anatomical Record: Advances in Integrative Anatomy and Evolutionary Biology. The study was funded through a grant from the National Science Foundation.

Anthony Fiorillo, a paleontologist at the Museum of Nature and Science, excavated Cretaceous Period fossils along Alaska's North Slope. Most of the bones belonged to Edmontosaurus, a duck-billed herbivore, but some others such as the horned dinosaur Pachyrhinosaurus were also found.

Fiorillo hypothesized that the microscopic structures of the dinosaurs' bones could show how they lived in polar regions. He enlisted the help of Allison Tumarkin-Deratzian, an assistant professor of earth and environmental science, who had both expertise and the facilities to create and analyze thin layers of the dinosaurs' bone microstructure.

Another researcher, Anusuya Chinsamy-Turan, a professor of zoology at the University of Cape Town, was independently pursuing the same analysis of Alaskan Edmontosaurus fossils. When the research groups discovered the similarities of their studies, they decided to collaborate and combine their data sets to provide a larger sampling. Half of the samples were tested and analyzed at Temple; the rest were done in South Africa.

"The bone microstructure of these dinosaurs is actually a record of how these animals were growing throughout their lives," said Tumarkin-Deratzian. "It is almost similar to looking at tree rings."

What the researchers found was bands of fast growth and slower growth that seemed to indicate a pattern.

"What we found was that periodically, throughout their life, these dinosaurs were switching how fast they were growing," said Tumarkin-Deratzian. "We interpreted this as potentially a seasonal pattern because we know in modern animals these types of shifts can be induced by changes in nutrition. But that shift is often driven by changes in seasonality."

The researchers questioned what was causing the dinosaurs to be under stress at certain times during the year: staying up in the polar region and dealing with reduced nutrition during the winter or migrating to and from lower latitudes during the winter.

They did bone microstructure analysis on similar duck-billed dinosaur fossils found in southern Alberta, Canada, but didn't see similar stress patterns, implying that those dinosaurs did not experience regular periodic seasonal stresses. "We had two sets of animals that were growing differently," said Tumarkin-Deratzian.

Since the Alaska fossils had all been preserved in the same sedimentary horizon, Fiorillo examined the geology of the bonebeds in Alaska where the samples were excavated and discovered that these dinosaurs had been preserved in flood deposits.

"They are very similar to modern flood deposits that happen in Alaska in the spring when you get spring melt water coming off the Brooks Mountain Range," said Fiorillo. "The rivers flood down the Northern Slope and animals get caught in these floods, particularly younger animals, which appear to be what happened to these dinosaurs.

"So we know they were there at the end of the dark winter period, because if they were migrating up from the lower latitudes, they wouldn't have been there during these floods," he said.

There's not a lot of endotherms of size in the very northern latitudes that winter over.

HPC Meet Paleontology: Simulating the Gait of Hadrosaurs

The team – from The University of Manchester, University of Oregon and Yale - set up the ‘dinosaur dressage’ with the help of Hector, the UK Research Council’s supercomputer, currently the 20th fastest super computer in the world.

They found that hopping hadrosaurs were fastest but – for safety reasons - a two-legged running gait was most likely. In the same way that we can all muster a John Cleese ‘silly walk’ few can sustain it!

In addition the team, funded by National Geographic and The Natural Environment Research Council, has shown how more research can be done to find out how large and fast animals moved, both living and extinct.

In the meantime, Jurassic fanatics can simulate their very own dinosaur as the software (Windows, Mac, Linux) and models are freely available to download from http://www.animalsimulation.org.

Team leader Dr Bill Sellers, whose results are published in Palaeontologica Electronica this week, explains: “Everyone knows that dinosaurs come in all shapes and sizes. Most don't look like anything that's alive today and some are just plain bizarre. One group that fit this description well is the duck-billed dinosaurs, also known as hadrosaurs. Along with the strange appearance – the eponymous duck-bill, peculiar skull ornaments, and long, slender forelimbs – scientists have argued about how they might have moved. Did they walk on four limbs, two limbs, or a combination of both depending on the speed? It has even been suggested that some may have hopped like a kangaroo!

“Previously we have used computer simulation to calculate the top running speed of a range of two-legged dinosaurs. It turns out that looking at all the possible locomotor options in a single four-legged dinosaur is actually much trickier. Much like a dressage trained horse, the basic body shape is capable of using a whole range of possible gaits even though it is likely that it would much prefer some over others.”

His colleague Dr Phil Manning, a palaeontologist at the University of Manchester, says: “Hadrosaurs are a much overlooked group of dinosaurs, often coming second place to the predators, such as their contemporary T. rex. However, in this running race, it seems that the hadrosaurs had the edge on the predators...not surprising if they wanted to survive in a landscape shared by the largest predator on Earth.

“Fortunately for us Hector had just come online and could provide sufficient computational power for the job. We gave the computer simulation a completely free rein to come up with whatever form of locomotion it could. And indeed from a completely random set of starting conditions the model generated a full range of possible gaits: bipedal running and hopping as well as quadrupedal trotting, pacing and galloping.

“The big surprise was that hopping gait came out as fastest at 61 km/h, followed by quadrupedal galloping (58 km/h), and bipedal running (50 km/h).”

Dr Sellers, based at Manchester’s Faculty of Life Sciences, adds: “We also looked at how these different ways of moving would apply forces to the skeleton. Here hopping came out the worst: if the hadrosaur had moved like that it would have destroyed its own skeleton.

“In the end bipedal running came out as probably the best compromise between performance and skeletal loading. But the really clear message is that there is still more research to be done particularly looking at how large and fast animals can move within the margins of safety required by their skeletons.”

No speeding tickets *HERE*!

The paper is located here.

Dakota Gives Up Hadrosaur Skin Secrets

There's no evidence of goosebumps just yet, but a remarkably preserved dinosaur reveals that the prehistoric reptile had skin like that of birds and crocodiles, a new study says.

"This is the closest you're going to get to patting the animal," said excavation leader Phillip Manning, a paleontologist at Britain's University of Manchester.

Advanced imaging and chemical techniques revealed that the 66-million-year-old "mummified" duckbilled dinosaur had two layers of skin, as do modern vertebrates, including humans.

Such a discovery was possible because the dinosaur's skin fossilized before bacteria had a chance to eat up the tissue.

[...]

With electron microscopes and x-rays, Manning discovered that Dakota had cell-like structures indicative of two-ply skin: a thin surface layer plus an underlying layer of dense connective tissues.

That's just like skin of modern birds and reptiles, which scientists believe are closely related to duckbilled dinosaurs.

Protein-recovery techniques used on the skin and a claw detected amino acids, the building blocks of proteins. Proteins themselves, complex molecules that degrade easily over time, were not found, however.

But Manning did identify molecules that would have broken down proteins in Dakota's body.

That's like finding fragments of a broken vase instead of the intact vase, explained Thomas R. Holtz Jr., a vertebrate paleontologist at the University of Maryland.

Again, no time, but it is really good to see the famed dino mummies producing papers for a change, instead of just news stories.

Hadrosaur Tooth Wear Patterns Reveal Chewing Methodology

Microscopic analysis of scratches on dinosaur teeth has helped scientists unravel an ancient riddle of what a major group of dinosaurs ate- and exactly how they did it!

Now for the first time, a study led by the University of Leicester, has found evidence that the duck-billed dinosaurs- the Hadrosaurs- in fact had a unique way of eating, unlike any living creature today.

Working with researchers from the Natural History Museum, the study uses a new approach to analyse the feeding mechanisms of dinosaurs and understand their place in the ecosystems of tens of millions of years ago. The results are published today in the Proceedings of the National Academy of Sciences.

Palaeontologist Mark Purnell of the University of Leicester Department of Geology, who led the research, said: "For millions of years, until their extinction at the end of the Cretaceous, duck-billed dinosaurs – or hadrosaurs - were the World's dominant herbivores. They must have been able to break down their food somehow, but without the complex jaw joint of mammals they would not have been able to chew in the same way, and it is difficult to work out how they ate. It is also unclear what they ate: they might have been grazers, cropping vegetation close to the ground - like today's cows and sheep - or browsers, eating leaves and twigs - more like deer or giraffes. Not knowing the answers to these questions makes it difficult to understand Late Cretaceous ecosystems and how they were affected during the major extinction event 65 million years ago.

"Our study uses a new approach based on analysis of the microscopic scratches that formed on hadrosaur's teeth as they fed, tens of millions of years ago. The scratches have been preserved intact since the animals died. They can tell us precisely how hadrosaur jaws moved, and the kind of food these huge herbivores ate, but nobody has tried to analyse them before."

The researchers say that the scratches reveal that the movements of hadrosaur teeth were complex and involved up and down, sideways and front to back motion. According to Paul Barrett palaeontologist at the Natural History Museum "this shows that hadrosaurs did chew, but in a completely different way to anything alive today. Rather than a flexible lower jaw joint, they had a hinge between the upper jaws and the rest of the skull. As they bit down on their food the upper jaws were forced outwards, flexing along this hinge so that the tooth surfaces slid sideways across each other, grinding and shredding food in the process".

The scratch patterns provide confirmation of a theory of hadrosaur chewing first proposed 25 years ago, and provides new insights into their ecology, say the researchers.

The research also sheds light on what the dinosaurs ate. Vince Williams of the University of Leicester said: "Although the first grasses had evolved by the Late Cretaceous they were not common and it is most unlikely that grasses formed a major component of hadrosaur diets. We can tell from the scratches that the hadrosaur's food either contained small particles of grit, normal for vegetation cropped close to the ground, or, like grass, contained microscopic granules of silica. We know that horsetails were a common plant at the time and have this characteristic; they may well have been an important food for hadrosaurs".

Has anyone done this for ceratopsians?

Quantitative analysis of dental microwear in hadrosaurid dinosaurs, and the implications for hypotheses of jaw mechanics and feeding

1. Vincent S. Williams (a),
2. Paul M. Barrett (b)
3. Mark A. Purnell (a,1)


a. Department of Geology, University of Leicester, Leicester LE1 7RH, United Kingdom;
b. Department of Palaeontology, Natural History Museum, Cromwell Road, London SW7 5BD, United Kingdom

Abstract:

Understanding the feeding mechanisms and diet of nonavian dinosaurs is fundamental to understanding the paleobiology of these taxa and their role in Mesozoic terrestrial ecosystems. Various methods, including biomechanical analysis and 3D computer modeling, have been used to generate detailed functional hypotheses, but in the absence of either direct observations of dinosaur feeding behavior, or close living functional analogues, testing these hypotheses is problematic. Microscopic scratches that form on teeth in vivo during feeding are known to record the relative motion of the tooth rows to each other during feeding and to capture evidence of tooth–food interactions. Analysis of this dental microwear provides a powerful tool for testing hypotheses of jaw mechanics, diet, and trophic niche; yet, quantitative analysis of microwear in dinosaurs has not been attempted. Here, we show that analysis of tooth microwear orientation provides direct evidence for the relative motions of jaws during feeding in hadrosaurid ornithopods, the dominant terrestrial herbivores of the Late Cretaceous. Statistical testing demonstrates that Edmontosaurus teeth preserve 4 distinct sets of scratches in different orientations. In terms of jaw mechanics, these data indicate an isognathic, near-vertical posterodorsal power stroke during feeding; near-vertical jaw opening; and propalinal movements in near anterior and near posterior directions. Our analysis supports the presence of a pleurokinetic hinge, and the straightness and parallelism of scratches indicate a tightly controlled occlusion. The dominance of scratched microwear fabrics suggests that Edmontosaurus was a grazer rather than a browser.

1. To whom correspondence should be addressed. E-mail: mark.purnell@le.ac.uk

Link to paper.

Murder in the Mesozoic

The discovery of a gruesome feeding frenzy that played out 73 million years ago in northwestern Alberta may also lead to the discovery of new dinosaur species in northwestern Alberta.

University of Alberta student Tetsuto Miyashita and Frederico Fanti, a paleontology graduate student from Italy, made the discovery near Grande Prairie, 450 kilometres northwest of Edmonton.

Miyashita and Fanti came across a nesting site and found the remains of baby, plant-eating dinosaurs and the teeth of a predator. The researchers matched the teeth to a Troodon, a raptor-like dinosaur about two metres in length. This finding has opened new doors in dinosaur research on this part of the continent: "It established that dinosaurs were nesting at this high latitude," said Miyashita. "It also shows for the first time a significant number of Troodons in the area [who] hunted hatchling dinosaurs."

Over the course of two summers of field work Miyashita and Fanti began building a theory that Grande Prairie is a "missing link" between known dinosaur species that existed much further to the north and south. "Prior to this there were no localities with a variety of dinosaurs and other animals between Alaska and southern Alberta," said Myiashita. The list of new finds for the area includes armoured and thick-headed plant eaters and fossilized freshwater fish and reptiles.

Miyashita says this small pocket of previously undiscovered life could have had interactions that lead to the evolution of new species.

"New dinosaurs weren't created by interbreeding," said Miyashita. "Having a variety of dinosaurs in one area creates new ecological interactions such as competition for food and predation.

"That can lead to the evolution of a new species."

One Grande Prairie dinosaur the researchers suspect is a new species is the Duck bill. Miyashita says unlike the Duck bill found further north in Alaska, the Grande Prairie has a visible bump or crest on its forehead.

I wonder what the size difference between the Troodons is there and in Alaska and further south. New hadrosaur! Yeah! Let's increase the diversity!!!