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Bernissart Dinosaurs and Early Cretaceous Terrestrial Ecosystems

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In 1878, the first complete dinosaur skeleton was discovered in a coal mine in Bernissart, Belgium. Iguanodon, first described by Gideon Mantell on the basis of fragments discovered in England in 1824, was initially reconstructed as an iguana-like reptile or a heavily built, horned quadruped. However, the Bernissart skeleton changed all that. The animal was displayed in an upright posture similar to a kangaroo, and later with its tail off the ground like the dinosaur we know of today. Focusing on the Bernissant discoveries, this book presents the latest research on Iguanodon and other denizens of the Cretaceous ecosystems of Europe, Asia, and Africa. Pascal Godefroit and contributors consider the Bernissart locality itself and the new research programs that are underway there. The book also presents a systematic revision of Iguanodon; new material from Spain, Romania, China, and Kazakhstan; studies of other Early Cretaceous terrestrial ecosystems; and examinations of Cretaceous vertebrate faunas.

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1 Bernissart and the Iguanodons: Historical Perspective and New Investigations

ePub

Pascal Godefroit*, Johan Yans, and Pierre Bultynck

The discovery of complete and articulated skeletons of Iguanodon at Bernissart in 1878 came at a time when the anatomy of dinosaurs was still poorly understood, and thus considerable advances were made possible. Here we briefly describe, mainly from documents in the archives of the Royal Belgian Institute of Natural Sciences, the circumstances of the discovery of the Bernissart iguanodons. We also provide information about their preparation and mounting in laboratories, for exhibitions, and in early studies. We also summarize the latest results of a multidisciplinary project dedicated to the material collected in the cores drilled in 2002–2003 in and around the Iguanodon Sinkhole at Bernissart.

1.1. The Sainte-Barbe pit and mine buildings in 1878, at the time when the iguanodons were discovered.

The discovery of the first Iguanodon fossils has become a legend in the small world of paleontology. Around 1822, Mary Ann Mantell accompanied her husband, the physician Dr. Gideon Algernon Mantell, on his medical rounds and by chance discovered large fossilized teeth. Her husband found the teeth intriguing. With advice from Georges Cuvier, William Clift, and William Daniel Conybeare, he described them and named them Iguanodon, “iguana tooth,” because of their superficial resemblance to those of living iguanas (Mantell, 1825). Iguanodon was one the three founding members of the Dinosauria—along with Megalosaurus and Hylaeosaurus—named by Richard Owen in 1842.

 

2 The Attempted Theft of Dinosaur Skeletons during the German Occupation of Belgium (1914–1918) and Some Other Cases of Looting Cultural Possessions of Natural History

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Christoph Roolf

This contribution focuses on the attempted theft of dinosaur skeletons during the German occupation of Belgium in 1914–1918 and addresses some other cases of looting cultural possessions of natural historic value in modern European history. It is not just a question of single incidents that have occurred in the history of science during times of war and occupation. As examples of forced Kulturtransfer, they rather turn out to be an integral part of a general history of international science relations, oscillating between cooperation and conflict.

My contribution deals with the hitherto largely unknown attempts of German scientists to seize Belgian cultural possessions during World War I.1 Probably the most spectacular examples of these are the activities of German paleontologists and German natural history museums at the biggest dinosaur excavation site in Europe, which is located in the Belgian town of Bernissart. These took place during the German occupation of the country between 1914 and 1918. Following a plan of the German paleontologist Otto Jaekel, launched in spring 1915, more Iguanodon skeletons were to be excavated and transferred to German natural history museums. The work began in July 1916 and ended, without results, with the retreat of German troops from Belgium in late 1918.2

 

3 A Short Introduction to the Geology of the Mons Basin and the Iguanodon Sinkhole, Belgium

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Jean-Marc Baele*, Pascal Godefroit, Paul Spagna, and Christian Dupuis

Bernissart is located in the northern part of the Mons Basin, which consists of a 300-m-thick pile of Meso-Cenozoic sediments that accumulated in a small but actively subsiding area. Sedimentation initiated in the Lower Cretaceous with continental siliciclastics, from which the iguanodons were recovered at Bernissart, and continued under marine conditions during the Cretaceous and more changing environments during the Tertiary. Subsidence in the Mons Basin was mainly controlled by intrastratal dissolution of deep evaporite beds in the Mississippian basement. Localized collapse structures, such as sinkholes or natural pits, developed throughout the basin and trapped the Barremian lacustrine clay with dinosaurs and other taxa at Bernissart.

Bernissart is located in the northwestern part of the Mons Basin, western Belgium, just next to the French border. The Mons Basin is a small but peculiar subsiding zone predominantly originating from deep karstification processes. Here we provide the essentials of the geological context and processes in the Bernissart area for understanding the geological environment of the deposits that have yielded the Iguanodon skeletons.

 

4 3D Modeling of the Paleozoic Top Surface in the Bernissart Area and Integration of Data from Boreholes Drilled in the Iguanodon Sinkhole

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Thierry Martin*, Johan Yans, Christian Dupuis, Paul Spagna, and Olivier Kaufmann

Since 1878–1881 and the discovery of numerous complete skeletons of dinosaurs in Bernissart (Belgium), many studies have been dedicated to the paleontological content of the Iguanodon Sinkhole. However, little is known about the geometry of the sinkhole and its integration within the Paleozoic basement of the Mons Basin. In 2002–2003, three new boreholes (BER 2, BER 3, and BER 4) provided us with the opportunity to improve our understanding of the geometry of the sinkhole by integrating the new data into a 3D model of the top surface of the Paleozoic basement. To achieve this, the 3D model of the top surface of the Paleozoic was created at a regional scale (an area of 340 km2), in the western part of the Mons Basin, near the French border. This area was delimited in order to contain enough data to outline the overall geometry. The methodology used in this study was previously developed for modeling the Meso-Cenozoic cover in the eastern part of the Mons Basin. Both the BER 2 (Z = 33 m) and BER 3 (Z = 24 m) cores cut the Wealden facies before reaching the Carboniferous basement, respectively at −291 m and −315 m below ground level. The BER 4 did not reach the natural pit, with the clayey sediments found at −246 m being attributed to the weathered Namurian basement.

 

5 The Karstic Phenomenon of the Iguanodon Sinkhole and the Geomorphological Situation of the Mons Basin during the Early Cretaceous

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Yves Quinif* and Luciane Licour

During the Late Jurassic and the Early Cretaceous, an extensional tectonic regime induced fracturation in carbonated Mississippian formations, notably enhanced their permeability, and initiated karstification. The low hydraulic potential that prevailed during the Cretaceous gave birth to the ghost rock karstification of the outcropping Mississippian limestone north of the Mons Basin. Deep water circulation also set in carbonated and sulfated strata, following convection induced by thermal contrast effects on water density, with the outcrop acting both as recharge and discharge area. Karstification resulting from these circulations left traces in the breccia pipes locally called “natural pits,” including the famous Iguanodon Sinkhole at Bernissart.

5.1. Distribution of the sinkholes in Hainaut province (Belgium) and northeastern France.

The Iguanodon Sinkhole is one of the numerous collapse features crossing Pennsylvanian formations that are known from the French Nord-Pas-de-Calais coal basin (Puits de Dièves) to the region of Charleroi (Belgium; see Fig. 5.1). These geological structures are locally named “natural pits.”

 

6 Geodynamic and Tectonic Context of Early Cretaceous Iguanodon-Bearing Deposits in the Mons Basin

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Sara Vandycke* and Paul Spagna

The Wealden facies sediments of the Mons Basin, where the Bernissart iguanodons were discovered, are affected by multiple tectonic features. Different systems of faulting and fracturing are observed in terms of type, orientation, movements, and dating: reverse and normal faults, and strike-slip faults and joints. The synsedimentary character of the deformation is particularly clear in the clayey sediments of the Early Cretaceous Hautrage Clays Formation. The local interaction between tectonic and karstic phenomena discussed here contributes to the trapping and the conservation of the Wealden fossil-rich deposits in a floodplain depositional environment confined to the northern flank of the future Mons Basin. In this area, Lower Cretaceous sediments also recorded several younger tectonic phases due to the proximal influences of regional crustal zones, such as inversion tectonics at the end of the Cretaceous and extensional regimes linked to the dynamics of the lower Rhine Graben Embayment.

 

7 Biostratigraphy of the Cretaceous Sediments Overlying the Wealden Facies in the Iguanodon Sinkhole at Bernissart

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Johan Yans*, Francis Robaszynski, and Edwige Masure

The stratigraphy of the Cretaceous sediments overlying the dinosaur-bearing Wealden facies intersected by the BER 3 borehole in the Iguanodon Sinkhole at Bernissart (Mons Basin, Belgium) is assessed. These Cretaceous strata are Late Albian to Coniacian in age, according to the foraminifera and dinocyst assemblages. The beds directly overlying the Wealden facies (Harchies Formation) are early Late Albian in age. The Catillon Formation is late Late Albian. The Bracquegnies Formation is “Vraconnian” (latest Albian, Dispar Zone). The lowermost part of the Bernissart Calcirudites Formation would be Early Cenomanian in age. The overlying Thivencelles Marls Formation is Early Turonian. The uppermost Cenomanian is lacking in the BER 3 borehole as it has been observed elsewhere in Bernissart and along the northern margin of the Mons Basin. The overlying Thulin Marls, Ville-Pommeroeul Chert, and Hautrage Flints formations are Turonian. The uppermost chalks are Coniacian. All of these Cretaceous strata overlay the Wealden facies of late Late Barremian to earliest Aptian age and are unconformably overlain by the Hannut Formation of Thanetian age. These results refine the stratigraphic framework of the Mons Basin.

 

8 On the Age of the Bernissart Iguanodons

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Johan Yans*, Jean Dejax, and Johann Schnyder

We summarize the studies dealing with the dating of the Bernissart iguanodons. Both palynology (especially pollens of angiosperm affinities, such as the biorecord Superret-croton and probably the paleotaxon Superret-subcrot) and chemostratigraphy (carbon isotope composition of dispersed organic matter and fossil wood) have recently been applied to refine the age of the Iguanodon-bearing Wealden facies trapped in the Iguanodon Sinkhole at Bernissart (Sainte-Barbe Clays Formation). These studies suggest that this formation is late Late Barremian to earliest Aptian in age.

Although numerous studies are dedicated to the faunal and floral content of the Iguanodon Sinkhole at Bernissart, the age of the Sainte-Barbe Clays Formation (Wealden facies) remained poorly constrained until recently. In the most recent synthesis on the Cretaceous of Belgium, Robaszynski et al. (2001) concluded that this formation was Late Jurassic to Early Cretaceous in age (161.2 to 99.6 Ma, according to Gradstein et al., 2004). Here we summarize the previous attempts to date the Bernissart iguanodons and discuss new datings on the basis of both palynology of the angiosperm pollen content and carbon isotope chemostratigraphy on organic matter.

 

9 The Paleoenvironment of the Bernissart Iguanodons: Sedimentological Analysis of the Lower Cretaceous Wealden Facies in the Bernissart Area

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Paul Spagna*, Johan Yans, Johann Schnyder, and Christian Dupuis

The Wealden facies at Hautrage and Bernissart (Mons Basin, Belgium) have been investigated following different sedimentological parameters, including lithofacies evolution, mineralogical and granulometric data, and organic matter properties. A six-step paleoenvironmental evolution can be observed in the Hautrage Clays Formation at Hautrage (10 km from Bernissart), in relation with the variation of the base level (deepening upward) inside a floodplain. Three sedimentological units can be recognized in the Sainte-Barbe Clays Formation of the Iguanodon Sinkhole at Bernissart, leading to a 2D modeling of the Bernissart paleolake. A schematic east–west paleovalley map is finally proposed, integrating all the new paleoenvironmental information collected in the Wealden facies from the Mons Basin.

9.1. Log and synthesis of different sequences recognized in the Hautrage Clays Formation in the Wealden facies of the Hautrage pocket. From Spagna (2010).

 

10 Mesofossil Plant Remains from the Barremian of Hautrage (Mons Basin, Belgium), with Taphonomy, Paleoecology, and Paleoenvironment Insights

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Bernard Gomez*, Thomas Gillot, Véronique Daviero-Gomez, Clément Coiffard, Paul Spagna, and Johan Yans

Seven beds bearing mesofossil plant remains have been sampled from the late Early to early Late Barremian Hautrage Clays Formation in the Danube-Bouchon quarry at Hautrage (Mons Basin, Belgium). They include various fertile and sterile parts of ferns (Weichselia reticulata (Stokes et Webb) Fontaine, Phlebopteris dunkeri Schenk, Gleichenites nordenskioeldii (Heer) Seward), Cheirolepidiaceae (Alvinia Kvaček, Frenelopsis (Schenk) Watson), Miroviaceae (Arctopitys Bose et Manum), Taxodiaceae (Sphenolepis Schenk), other conifers (Brachyphyllum Brongniart and Pagiophyllum Heer), and Ginkgoales (Pseudotorellia Florin). Although the plant assemblages vary from one bed to another, the taxa remain globally unchanged, suggesting repeated vegetation changes that may be related to lateral divagations of stream channels in a continental freshwater floodplain. Integration of taphonomic and sedimentological data suggest that fires may have played a role in the production, transport, and preservation of the mesofossil plant remains that may mostly represent the local vegetation.

 

11 Diagenesis of the Fossil Bones of Iguanodon bernissartensis from the Iguanodon Sinkhole

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Thierry Leduc

We investigate the bone diagenesis of the Iguanodon skeletons discovered in the Iguanodon Sinkhole in 1878–1881. By means of x-ray diffraction and energy-dispersive spectrometry analysis, about 30 mineral phases were identified in the fossil bones of the Bernissart iguanodons. During burial, recrystallization took place: the slightly crystallized carbonated hydroxylapatite (the mineral phase of fresh bone tissue) was replaced by well-crystallized carbonated fluorapatite, currently present in the Iguanodon bones. Whereas some minerals infiltrated the bone during cavity filling by the sediment (detrital quartz, “argillaceous” phyllosilicates, anatase, and rutile), others are authigenic and precipitated in the cavities during burial (pyrite, barite, sphalerite, celestine, and to a lesser extent quartz) or after the exhumation (other sulfates, oxides, and/or hydroxides). Pyrite is the most abundant authigenic mineral in the Iguanodon fossil bones, making them brittle. Different pyrite morphologies can be observed, such as crystals, framboids, thin coatings, and fibroradial structures. Barite is the second most abundant phase. When both minerals are present, pyrite was formed first. Their distribution throughout the bones seems to be random. Since their discovery, the fossil bones have been treated for conservation in several ways. However, this treatment did not prevent the alteration of pyrite into an assemblage of 13 different secondary sulfate minerals, more particularly szomolnokite (FeSO4 · H2O) and rozenite (FeSO4 · 4 H2O) and in a less way roemerite (Fe2+Fe3+2SO4 · 14 H2O), jarosite [KFe3(SO4)2(OH)6], natrojarosite [NaFe3(SO4)2(OH)6], halotrichite [Fe2+Al2(SO4)4 · 22 H2O], tschermigite [(NH4)Al(SO4)2 · 12 H2O)], melanterite (FeSO4· 7 H2O), coquimbite [Fe3+2(SO4)3 · 9 H2O], metavoltine [(K,Na)8Fe2+Fe3+6(SO4)12O2 · 18 H2O], gypsum (CaSO4 · H2O), anhydrite (CaSO4), and pure sulfur (S). Szomolnokite and rozenite are the most abundant of these minerals and can be found in nearly all samples. These two minerals differ only by their degree of hydration and can easily transform into each other. This mechanism depends on the degree of humidity in the environment. Barite and anhydrite are the result of the neutralization of the acid by phosphate or carbonate.

 

12 Histological Assessment of Vertebrate Remains in the 2003 Bernissart Drill

ePub

Armand de Ricqlès*, Pascal Godefroit, and Johan Yans

After the 2003 drilling in the Iguanodon Sinkhole at Bernissart (BER 3 borehole), examination of the column revealed stony dark grayish remains at levels −296.5 m and −309 m, and hence within the Wealden clays levels. Microscopic examinations of the remains (paleohistology) conclusively demonstrate the occurrence of bone and tooth tissues. Whether the histological characteristics of the tissues allow a precise identification, especially whether the remains belong to Iguanodon, is quite another matter. The small teeth material clearly does not belong to ornithopod dinosaurs; however, their precise taxonomic origin cannot be assessed. However, the bony material shows structures compatible with a dinosaurian origin. A survey of the literature devoted to Iguanodon bone and tooth histology, as well as comparisons with Iguanodon bernissartensis bone and tooth material and with Bactrosaurus johnsoni teeth, do not demonstrate that the material definitely belongs to Iguanodon, although the possibility is likely for several reasons, detailed herewith. Comparison between “fresh” (from the borehole) and “old” (kept in the RBINS for more than 130 years under ordinary conditions) Iguanodon bones also allows checking the degradation process experienced by pyritized bones at the tissue level.

 

13 Early Cretaceous Dinosaur Remains from Baudour (Belgium)

ePub

Pascal Godefroit*, Jean Le Loeuff, Patrick Carlier, Stéphane Pirson, Johan Yans, Suravech Suteethorn, and Paul Spagna

We describe two dinosaur bones found in the Bois de Baudour clay quarries (Mons Basin, Belgium) of the Baudour Clays Formation (middle Barremian to earliest Aptian) during their exploitation period. Apart from the numerous skeletons found in the Sainte-Barbe pit at Bernissart, these are the only dinosaur fossils discovered in Wealden deposits in the Mons Basin. The first bone is a left coracoid that can confidently be attributed to the ornithopod Iguanodon bernissartensis. The second bone is a left tibia belonging to an indeterminate sauropod. This is the first sauropod bone from Cretaceous deposits in Belgium. Recent drillings in the Baudour Clays Formation at Bois de Baudour suggest that the Baudour and Hautrage areas were probably parts of the same floodplain environment. A bone fragment, probably a fragment of a vertebral centrum, was found in the drilling core about 14 m below the ground surface. Paleoecological conditions in the Baudour and Hautrage formations were apparently not favorable at all for the preservation of in situ complete skeletons, like those from the Bernissart Sinkhole. However, drilling through a bone does suggest a high concentration of fossils.

 

14 Geological Model and Cyclic Mass Mortality Scenarios for the Lower Cretaceous Bernissart Iguanodon Bonebeds

ePub

Jean-Marc Baele*, Pascal Godefroit, Paul Spagna, and Christian Dupuis

The Iguanodon Sinkhole at Bernissart (Belgium) is an exceptional fossil deposit as a result of the quantity and preservation quality of Cretaceous basal Iguanodontia found by coal mine workers in 1878. Efforts to unravel the processes that caused the accumulation and preservation of many dinosaurs, along with other taxa, are here based on a new geological model that relies on several discrete, continuous bonebeds. Several taphonomic scenarios are proposed and discussed within the specific geological and environmental specificities of the so-called Lower Cretaceous Bernissart paleolake. On the basis of sedimentological and taphonomic evidence, attrition and obrution processes appear less likely than mass death by drowning and/or intoxication. Contamination of the aquatic environment by sulfate-rich brines related to deep solution–collapse processes could support the hypothesis of intoxication by H2S or biological toxins as a direct or indirect lethal agent in a context of seasonally shrinking water.

 

15 Iguanodontian Taxa (Dinosauria: Ornithischia) from the Lower Cretaceous of England and Belgium

ePub

David B. Norman

This review summarizes current understanding of the history, anatomy, and taxonomy of British and Belgian iguanodontian dinosaurs. The earliest iguanodontian from this circumscribed region is Berriasian in age and represented by a well-preserved but crushed dentary with many teeth in situ; originally named Iguanodon hoggii Owen, 1874, this specimen has been studied and reassessed several times, and decisions concerning its taxonomic status and systematic position have proved to be consistently inconclusive. I. hoggii has recently been renamed Owenodon hoggii; however, the diagnostic anatomical characters that form the foundation for this new name are few and not taxonomically or systematically robust. It is considered appropriate to regard this undoubtedly important taxonomic entity as indicative of a basal (ankylopollexian) iguanodontian and to encourage new exploration for additional skeletal remains from Berriasian-aged deposits in England. Wealden iguanodontian taxonomy in England has also begun to be scrutinized more thoroughly. Difficulties encountered when trying to diagnose the original (Valanginian) type genus (Iguanodon Mantell, 1825) and species (Iguanodon anglicus Holl, 1829) created problems that were resolved using a rather unfortunate workaround that involved the use of a Barremian–Lower Aptian species: I. bernissartensis Boulenger in Van Beneden 1881. With regard to remains collected from numerous Wealden localities in southern England, it was recognized that known iguanodontians can be subdivided into anatomically and chronologically distinct groupings: an earlier (Valanginian) “fauna” represented by Barilium dawsoni (Lydekker, 1888) and Hypselospinus fittoni (Lydekker, 1889), and a later (Barremian–Lower Aptian) “fauna” comprising Iguanodon bernissartensis Boulenger in Van Beneden, 1881, and Mantellisaurus atherfieldensis (Hooley, 1925). The Belgian locality at Bernissart, assigned to the Sainte-Barbe Clays Formation (late Barremian–Lower Aptian) has yielded two taxa that have been recognized as anatomically similar to those identified in the contemporaneous Wealden deposits of southern England (the Weald Clay Group of the Wealden District and the Wealden Group of the Isle of Wight). Recent suggestions that further taxa can be diagnosed within the English and Belgian Wealden sequences are assessed (and rejected) on the basis of the evidence presented.

 

16 The Brain of Iguanodon and Mantellisaurus: Perspectives on Ornithopod Evolution

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Pascaline Lauters*, Walter Coudyzer, Martine Vercauteren, and Pascal Godefroit

Information on the structure of the brain of the basal iguanodontian dinosaurs Iguanodon bernissartensis and Mantellisaurus atherfieldensis, from the Early Cretaceous of Bernissart, is presented on the basis of computed tomographic scanning and 3D reconstruction of three braincases. The resulting digital cranial endocasts are compared with physical and digital endocasts of other dinosaurs. The orientation of the brain is more horizontal than in lambeosaurine hadrosaurids. The large olfactory tracts indicate that the sense of smell was better developed than in hadrosaurids. The primitive flexures of the midbrain are virtually absent in I. bernissartensis but appear to be better developed in M. atherfieldensis, which might be explained by the smaller body size of the latter. The brain of Iguanodon was relatively larger than in most extant nonavian reptiles, sauropods, and ceratopsians. However, it was apparently smaller than in lambeosaurines and most theropods. The relative size of the cerebrum was low in Iguanodon. In Mantellisaurus, the cerebrum was proportionally larger than in Iguanodon and compares favorably with lambeosaurines. The behavioral repertoire and/or complexity were therefore probably different in the two iguanodontoids from Bernissart, Iguanodon and Mantellisaurus. The enlargement of the cerebrum appeared independently, together with possible capabilities for more complex behaviors, at least two times during the evolution of Iguanodontoidea.

 

17 Hypsilophodon foxii and Other Smaller Bipedal Ornithischian Dinosaurs from the Lower Cretaceous of Southern England

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Peter M. Galton

The cranial and postcranial anatomy and biology is detailed for Hypsilophodon foxii, a small cursorial (not arboreal) basal euornithopod with no confirmed record outside of the Isle of Wight (Late Barremian) of southern England. Three large distal femora with a wide distal extensor groove are reidentified. Two with a narrow more medially situated lateral flexor condyle are basal Ornithopoda. The other distal femur from Potton, which also has a lateral expansion of the medial flexor condyle partly overlaping the flexor groove, is identified as Iguanodontia. The record of the dryosaurid Valdosaurus is restricted to England. “Camptosaurus” valdensis Lydekker, 1889a, a femur, is a nomen dubium and basal Ornithopoda. Iguanodon hoggii Owen, 1874, the type species of Owenodon Galton, 2009, is represented by the small holotype dentary with tooth row from Dorset. Owenodon, which is also present in the Lower Cretaceous of Spain and Romania, is a basal member of the Styracosterna. A small dentary with three replacement teeth from the Isle of Wight (Late Barremian) is basal Iguanodontoidea indet., as are a small distal half femur from the Isle of Wight and a small femur from Dorset (Middle Berriasian). However, histological studies are needed to determine whether they represent juveniles of an already known taxon or whether they are adults of a new taxon. The taxonomic and size diversity of ornithischians of the Lower Cretaceous of southern England are calculated and listed for the different horizons

 

18 The African Cousins of the European Iguanodontids

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Philippe Taquet

In 1966, excavations in the Gadoufaoua locality (Niger) allowed us to describe two new genera of Early Cretaceous basal Iguanodontoidea from Africa: the first one, Ouranosaurus nigeriensis Taquet, 1976, was a gracile and facultative bipedal Iguanodontoidea, with bumped nasals on the skull and long neural spines on the dorsal vertebrae. The second one, Lurdusaurus arenatus Taquet and Russell, 1999, was a heavy, quadrupedal basal Styracosterna, with very short and robust limbs and a hippopotamus-like body. These two African basal iguanodontoids are closely related to the European iguanodontids, including Iguanodon bernissartensis and Mantellisaurus atherfieldensis from Bernissart locality; basal Iguanodontoidea probably migrated from Europe to Africa during the Early Cretaceous. Considering the Aptian dating of the Gadoufaoua locality and the morphologic evolution of the Nigerian iguanodontians, a Barremian age for the Bernissart iguanodons was suggested in 1975. This age was recently confirmed by palynological dating of the Wealden sediments of Bernissart.

 

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