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A new species of Polacanthus (Ornithischia; Ankylosauria) from the Lower Cretaceous of Sussex, England

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Abstract

The first specimen of the ankylosaur genus Polacanthus from the mainland Barremian of southeast England is described as Polacanthus rudgwickensis sp.nov. Polacanthus rudgwickensis is larger than Polacanthus foxii, and there are significant differences in the dermal armour, the tibia and caudal vertebrae of the two species. Polacanthus foxii appears to be restricted at present to the Isle of Wight with one specimen from southwest England, whilst Polacanthus rudgwickensis is only known from Sussex. This geographical distribution, the palaeobiological implications and possible sexual dimorphism are discussed for this genus.

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... In combination, this material represents much of the skeleton, including partial skulls that have been attributed to the taxon (Norman and Faiers, 1996). Finally, Horshamosaurus rudgwickensis from the Weald Clay Group (Hauterivian-Barremian) of West Sussex (Blows, 2015) was originally considered to be a second species of Polacanthus (Blows, 1996), although the holotype and only specimen is fragmentary. These Wealden taxa have traditionally been placed within the Nodosauridae (Coombs, 1978;Pereda-Suberbiola, 1993; Thompson et al., 2012), although a recent phylogenetic analysis found Hylaeosaurus to be an early-diverging member of Ankylosauridae . ...
... 'Horshamosaurus rudgwickensis' HORSM 1988.1546 was described as a second species of Polacanthus by Blows (1996) and was later reassigned to the new genus Horshamosaurus (Blows, 2015). It was found in the Weald Clay Group (Hauterivian-Barremian) of Sussex, on the mainland of southeast England, and was thought to be distinct from Polacanthus based on differences in the size of the specimen as well as anatomical differences in the osteoderms, tibia, and caudal vertebrae. ...
... HORSM 1988.1546 is, however, fragmentary; only a dorsal vertebra, a dorsal centrum, a caudal centrum, scapula, humerus, tibia, ribs, and osteoderms are known, and many of these elements are incomplete (Blows, 1996). Additionally, the phylogenetic position of the taxon is labile (Ősi, 2015); it has been referred to as a 'polacanthid' (Blows, 1996(Blows, , 2015Carpenter, 2001a), a nodosaurid (Thompson et al., 2012), and as Ankylosauria incertae sedis (Vickaryous et al., 2004). ...
Article
Ankylosaurs, dinosaurs possessing extensive body armor, were significant components of terrestrial ecosystems from the Middle Jurassic–latest Cretaceous. They diversified during the Early Cretaceous, becoming globally widespread. The Lower Cretaceous Wealden Supergroup (Berriasian–Aptian) of Britain has produced abundant ankylosaur material, with three currently recognized taxa: Hylaeosaurus armatus (Grinstead Clay Formation, West Sussex); Polacanthus foxii (Wessex Formation, Isle of Wight); and Horshamosaurus rudgwickensis (Weald Clay Group, West Sussex). However, these taxa are poorly understood; the initial descriptions of Hylaeosaurus and Polacanthus date from the 1800s and subsequent referrals of specimens have been based largely on provenance rather than morphological comparisons. This has led to uncertainty over the definitions of these taxa and the compositions of their hypodigms. Here, we redescribe the holotypes of Hylaeosaurus and Polacanthus, provide comparisons between these taxa, and use this information to assess the taxonomy of all ankylosaur specimens from the British Wealden Supergroup. We conclude that Hylaeosaurus and Polacanthus are valid, distinct taxa, which can be diagnosed by a combination of autapomorphies and a unique combination of characters. However, in both cases, we restrict their hypodigms to the holotypes. ‘Horshamosaurus rudgwickensis’ is a nomen dubium (an indeterminate nodosaurid dinosaur) and the majority of ankylosaur specimens from the Wealden Supergroup are taxonomically indeterminate. Hylaeosaurus and Polacanthus are separated stratigraphically, with Hylaeosaurus from the Valanginian of the Weald Sub-basin and Polacanthus from the Barremian of the Wessex Sub-basin. This separation supports the hypothesis of distinct lower and upper dinosaur faunas in the Wealden Supergroup of Britain.
... In a comprehensive guide to British polacanthid dinosaurs, Blows (2015, pp. 205-214) reclassified the ankylosaur Polacanthus rudgwickensis (Blows, 1996) as Horshamosaurus rudgwickensis. The holotype is based on a partial skeleton found at the Rudgwick site in West Sussex (Blows, 1996), which, owing to differences in the tibia and scapula, and the absence of a sacral shield and of ossicles normally found in abundance with other polacanthids, he felt was sufficiently different from other Polacanthus specimens to justify erecting the new genus Horshamosaurus. ...
... 205-214) reclassified the ankylosaur Polacanthus rudgwickensis (Blows, 1996) as Horshamosaurus rudgwickensis. The holotype is based on a partial skeleton found at the Rudgwick site in West Sussex (Blows, 1996), which, owing to differences in the tibia and scapula, and the absence of a sacral shield and of ossicles normally found in abundance with other polacanthids, he felt was sufficiently different from other Polacanthus specimens to justify erecting the new genus Horshamosaurus. ...
Article
The non-marine Wealden succession of southern England contains a great variety of fossils, new finds of which continue to reveal novel insights into the animals and plants that inhabited this part of the world during much of the Early Cretaceous. Although seldom common, careful searching during the past few years has yielded megafossils that add to previous knowledge of occurrences of taxa and palaeoenvironmental conditions. Particularly significant in this respect has been the recovery of a large number of new insect species, but there have also been numerous finds of vertebrate bones and other body parts, such as teeth, skulls, a claw and a cranial endocast. In addition, the taxonomy of some of these groups and, in the case of dinosaurs, the ichnotaxonomy of their footprints and trackways, has been reviewed and/or reassessed. In this paper, we provide an illustrated account of the research that has been published on Wealden geology and the fossils that have been recovered from the succession since a field guide to English Wealden fossils was issued by the Palaeontological Association in 2011. It is aimed at providing the reader with a document of first resort for fossil identification purposes and a lead into the literature for further information
... and NHMUK R9293) are the largest caudal vertebrae with shallow haemal arch facets and lateral (transverse) processes mounted high on the lateral centrum adjacent to the neural arch. The dorsal surface of these processes blends with the neural arch forming a ridge, a development that is prominent in Polacanthus rudgwickensis (HORSM 1988(HORSM .1546Blows, 1996). Progressing posteriorly, the vertebrae become more medium sized with moderate haemal arch attachments. At the mid-caudal sequence (e.g. BEXHM 2002.50.86) the lateral process has migrated downwards towards the mid-line of the centrum. The dorsal surface of the process becomes progressively more detached from the neural arch. By the late ...
... Both holotypes, Polacanthus and Hylaeosaurus, appear to be of approximately equal growth stages (sub-adult). Blows (1996) identified three possible characters which may be indicative of sexual dimorphism in Polacanthus, using NHMUK R175 and NHMUK R9293, i.e. variations in anterior caudal vertebrae, anterior caudal plates and ischium morphology. Unfortunately, these characters cannot be tested directly in Hylaeosaurus. ...
Article
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A new partial skeleton of the armoured ornithischian dinosaur Polacanthus found in the Wadhurst Clay Formation (Valanginian stage) of Bexhill, Sussex is the oldest recorded occurrence of this taxon. Previous discoveries suggested that at least two armoured ornithischians occur in the Wealden succession: Polacanthus, which was mostly restricted to the Barremian, and Hylaeosaurus, which was recorded as present only in the Valanginian. The new discovery extends the stratigraphic range of Polacanthus into the Valanginian. Although these two taxa appear to be closely similar anatomically, their osteology now suggests they are not synonymous. The new specimen includes the first known jugal as well as a comparatively rare polacanthid plate/spine (splate) which probably comes from the shoulder (pectoral) area of these animals.
... Additionally, in 1879, Seeley [16] described the juvenile nodosaurid Anoplosaurus curtonotus [17] from the uppermost Lower Cretaceous (upper Albian) Cambridge Greensand. Subsequent descriptions of the fragmentary remains of ankylosaurs from the Early Cretaceous of Europe have been tentatively assigned to the genus Polacanthus [18]. ...
... The proximal end is 169.2 mm wide by 93.1 mm wide and its distal end is 146.8 mm wide by 70.2 mm. It is significantly more narrowly waisted in Mymoorapelta [84], Gastonia [83], Polacanthus [7,12,18], Sauropelta [69,71,99,108], Peloroplites [86], and in Zhejiangosaurus [126] and ankylosaurids like Saichania [106]. The cnemial crest is broadly rounded. ...
Article
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Nodosaurids are poorly known from the Lower Cretaceous of Europe. Two associated ankylosaur skeletons excavated from the lower Albian carbonaceous member of the Escucha Formation near Ariño in northeastern Teruel, Spain reveal nearly all the diagnostic recognized character that define nodosaurid ankylosaurs. These new specimens comprise a new genus and species of nodosaurid ankylosaur and represent the single most complete taxon of ankylosaur from the Cretaceous of Europe. These two specimens were examined and compared to all other known ankylosaurs. Comparisons of these specimens document that Europelta carbonensis n. gen., n. sp. is a nodosaur and is the sister taxon to the Late Cretaceous nodosaurids Anoplosaurus, Hungarosaurus, and Struthiosaurus, defining a monophyletic clade of European nodosaurids- the Struthiosaurinae.
... 1. Straight ischium, not sharply bent as in nodosaurids. Blows (1996) indicated the presence of a relatively straight ischium in one specimen of Polacanthus (considered a nodosaurid by Thompson et al. 2012) and suggests this character may be a feature of sexual dimorphism in nodosaurids, not a character that can be used to separate the Nodosauridae from the Ankylosauridae. 2. Coracoid moderate in size, no ...
... Kirkland 1998; Vickaryous et al. 2004 ), " polacanthids " were found to be basal ankylosaurids. Blows (1987 Blows ( , 1996) considered polacanthids to be primitive nodosaurs. Other studies (e.g., Hill et al. 2003) only used characters of the skull and thus are of limited applicability to Scolosaurus. ...
Article
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The synonymy of the ankylosaurid dinosaur Scolosaurus with Euoplocephalus has been widely accepted since the 1970s. However, Scolosaurus cutleri exhibits differences which separate it from Euoplocephalus tutus and Dyoplosaurus acutosquameus. Although the holotype of Euoplocephalus is fragmentary, several other specimens can be reliably referred to this taxon and thus used for comparison. Scolosaurus differs from Euoplocephalus in cervical half-ring, osteoderm, and forelimb morphology. Scolosaurus differs from Dyoplosaurus primarily in pelvic morphology and osteoderm shape. Recognition of Scolosaurus as a valid taxon adds to the growing concept that the Upper Cretaceous ankylosaurid fauna of North America was more diverse than previously thought.
... Polacanthus is represented by two species. P. foxii Owen in Anon., 1865 was described for a partial skeleton from the Wessex Formation whereas P. rudgwickensis Blows, 1996 is from the Barremian Upper Weald Clay Formation of Rudgwick, West Sussex (Hulke 1881; Blows 1987 Blows , 1996 Pereda-Suberbiola 1993). Cranial material referred to P. foxii includes a partial neurocranium, a possible angular, and a tooth (Blows 1987; Norman & Faiers 1996; Naish & Martill 2001a). ...
... The characters that differentiate P. foxii from P. rudgwickensis are not entirely satisfactory, and unpublished specimens from the Isle of Wight and East Sussex are intermediate between the two. In addition to its presence in the Wessex Formation, P. foxii has been reported from the Vectis Formation and from a Lower Greensand Formation exposure between Humble Point and Pinhay Bay, Devon (Blows 1996). The latter record, initially reported as being from Charmouth, Dorset, lacks characters that allow its identification beyond Ankylosauria. ...
Article
Completing our survey of British non-avian dinosaurs, we here review the ornithischians of Britain. Heterodontosaurids are present in the Lower Cretaceous Lulworth Formation of Dorset, and a few earlier possible records imply a long presence in the region of this clade. Britain's thyreophoran record is rich and includes the earliest well-represented taxon, Scelidosaurus, as well as Middle Jurassic stegosaurs and ankylosaurs including a reasonably good Cretaceous record of polacanthids and nodosaurids. Cretaceous stegosaurs are known only from fragmentary remains, but the proposal that stegosaurs were present as early as the Rhaetian is rejected. Among British iguanodontian omithopods, the possible dryosaurid Callovosaurits is the oldest global record whereas the proposed synonymy of Cumnoria with Camptosaurus requires confirmation. Iguanodon has become a taxonomic dumping ground for assorted iguanodontians and is in need of revision: most of the British species referred to this genus are almost certainly not closely allied to the neotype species 1. bernissartensis and require new generic names. Fragmentary remains suggest the early presence of hadrosaurids in Britain. The only British record of Marginocephalia, the Wessex Formation skull roof named Yaverlandia bitholus, appears not to belong to this clacle but seems to be from a maniraptoran theropod.
... Though their fossils are known from sediments ranging from the Middle Jurassic to the uppermost Cretaceous, specimens are in many cases fragmentary with poorly preserved cranial material (see Ősi 2015 for a review). Multiple articulated or associated specimens of a single genus from Europe are only known in a few taxa: the Valanginian Hylaeosaurus based on two partial skeletons (Mantell 1833(Mantell , 1841Owen 1858;Pereda-Suberbiola 1993a;Carpenter 2001), the Barremian-early Aptian Polacanthus based on three partial skeletons (Owen 1865;Hulke 1882Hulke , 1888Blows 1982Blows , 1987Blows , 1996Blows , 2015Pereda-Suberbiola 1994;Naish and Martill 2001), the Albian Europelta based on five skeletons (Kirkland et al. 2013;Luis Alcalá, pers. comm, 2014) and the Santonian Hungarosaurus based on six associated skeletons (Ősi 2005;Ősi and Makádi 2009;Ősi 2015, in the paper). ...
Article
Ankylosaurian fossils are usually standard elements of Cretaceous continental vertebrate localities; however, bone-yielding horizons including more than one individual are extremely rare. Here, we present a unique assemblage of 12 partial, articulated or associated ankylosaurian skeletons and thousands of isolated bones and teeth discovered from the Santonian Iharkút vertebrate locality, western Hungary. Collected from an area of 600 m2 and from a single bone bed, this material is one of the richest ankylosaurian accumulation worldwide. The 12 skeletons are not monospecific but mostly based on the pelvic armour composition: six of them are from Hungarosaurus, two are referred to Struthiosaurus and four can be assigned to Nodosauridae indet. Sedimentological and taphonomical examinations revealed a single mass mortality event as the cause of the death and accumulation of these quadruped animals that are described here. The ankylosaur assemblage from Iharkút suggests at least a temporarily gregarious behaviour of these animals and also shows that Hungarosaurus and Struthiosaurus might live in the same moist habitat or at least preferred relatively close environments.
... Polacanthus foxii-partial skeleton NHMUK R 175 (Wessex Formation, Isle of Wight, UK); humerus NHMUK R1106 (Vectes Formation, Isle of Wight, UK); tibia NHMUK R1107 (Vectes Formation, Isle of Wight, UK); braincase CAMSM X.26242 (Wealden Group, Isle of Wight, UK). Described by BloWs (1987BloWs ( , 1996BloWs ( , 2015). Saichania chulsanensis-skull GI SPS 100/151 (Barun Goyot Formation, Mongolia; redescribed by Carpenter et al. 2011 as belonging to GI SPS 100/1305; GI SPS 100/1305 described by Carpenter et al. 2011 as the postcrania of Saichania at the recommendation of one of the coauthors. ...
Article
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The polacanthid ankylosaur Gastonia burgei, from the Lower Cretaceous Cedar Mountain Formation, Utah, USA, is described in detail for the first time and compared with material from a stratigraphically higher monospecific Gastonia bone bed. Taphonomy and sedimentology of the bone bed place the site within the lower part of the Ruby Ranch Member and suggest mass mortality, either due to drought or drowning while crossing a swollen river. Burial of the scavenged and disarticulated bones was by crevasse splay. Gastonia is characterized by a skull that is subtriangular in dorsal view, being nearly as wide as long, a cranial surface with a pustulate texture, and anteroventrally projecting basipterygoid processes. In the postcrania, the scapula has a well-developed, arcuate acromion flange that attaches to the midshaft. The body armor includes laterally projecting tetrahedron osteoderms that are grooved along the posterior sides, dorsoventrally compressed triangular plates along the sides of the body, and coossified pelvic shield of large, raised osteoderms surrounded by rosettes of smaller osteoderms. A new species of Gastonia, G. lorriemcwhinneyae n. sp., is identified from the bone bed material. It differs from Gastonia burgei in having a flat skull roof, short paroccipital processes that is proportionally less expanded distally, short postacetabular process of ilium that is only 36% of the length of the preacetabular process as compared to 56% in G. burgei, and an ischium that is smoothly curved ventromedially without kink at its midpoint. Its discovery adds a new species of ankylosaur to the Polacanthidae family found in the Cedar Mountain Formation.
... n.a. Blows (1996) Priconodon crassus aptian-albian only isolated teeth n.a. ...
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Ankylosaurian dinosaurs were low-browsing quadrupeds that were traditionally thought of as simple orthal pulpers exhibiting minimal tooth occlusion during feeding, as in many extant lizards. Recent studies, however, have demonstrated that effective chewing with tooth occlusion and palinal jaw movement was present in some members of this group. Qualitative and quantitative analysis of feeding characters (i.e. craniodental features, tooth wear patterns, origin and insertion of jaw adductors) reveal at least three different jaw mechanisms during the evolution of Ankylosauria. Whereas, in basal members, food processing was restricted to simple orthal pulping, in late Early and Late Cretaceous North American and European forms a precise tooth occlusion evolved convergently in many lineages (including nodosaurids and ankylosaurids) complemented by palinal power stroke. In contrast, Asian forms retained the primitive mode of feeding without any biphasal chewing, a phenomenon that might relate to the different types of vegetation consumed by these low-level feeders in different habitats on different landmasses. Further, a progressive widening of the muzzle is demonstrated both in Late Cretaceous North American and Asian ankylosaurs, and the width and general shape of the muzzle probably correlates with foraging time and food type, as in herbivorous mammals.
... We follow Arbour and Currie (in press) in excluding the highly fragmentary taxa "Tianchisaurus", Bissektipelta, and "Minmi paravertebra" by means of safe taxonomic deletion. We also excluded several others that caused a collapse in tree resolution; these include Anoplosaurus (Pereda Suberbiola and Barrett, 1999), Acanthopholis (Pereda Suberbiola and Barrett, 1999), Dracopelta (Galton, 1980), and Horshamosaurus (Blows, 1996;Blows 2015). Queensland Museum specimen F1801, previously Minmi sp., was recently given the new name Kunbarrasaurus ieversi (Leahey et al., 2015). ...
Article
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More species of nodosaurid ankylosaurians than ankylosaurid ankylosaurians have been found in marine sediments, and some previous quantitative studies of global dinosaur occurrences provide support for an association between nodosaurids and marine depositional environments. We compiled a dataset of global ankylosaurian occurrences and found that the geographic distribution of marine ankylosaurian occurrences is regionally biased with 54% of records stemming from western North America in the Cretaceous—a time of regional highstands in sea level and epicontinental flooding, coupled with differential extirpation of ankylosaurian subclades inhabiting the Western Interior Basin (WIB). Within the Western Interior Basin, we found little statistical support for an association between ankylosaurian subclades and palaeoenvironment in a chronological context. Only the Albian-Cenomanian transgressive-regressive cycle had statistical support for an overabundance of nodosaurids in marine environments compared to ankylosaurids. The apparent overabundance of nodosaurids relative to ankylosaurids in marine sediments in the Western Interior Basin overall cannot be decoupled from the extirpation of North American ankylosaurids during the Cenomanian and the subsequent absence of ankylosaurids in North America during the Turonian to early Campanian prior to the immigration of Asian ankylosaurine ankylosaurids. The North American ankylosaurian record highlights the difficulty in interpreting habitat preferences in the context of a shifting seaway, regional extinctions, and intercontinental dispersals.
... hallados en una cantera de Sussex (Inglaterra). Según Blows (1996Blows ( , 1998, P. rudgwickensis es una especie de mayor tamaño que P. foxii y presenta diferencias vertebrales, apendiculares y dermatoesqueléticas. Un tercer esqueleto parcial de Polacanthus, descubierto en 1993, está expuesto en una tienda de fósiles de la Isla de Wight, pero no ha podido ser estudiado hasta la fecha (Naish y Martill, 2001). ...
Article
DERMAL ARMOUR ELEMENTS OF THE ANKYLOSAUR DINOSAUR POLACANTHUS OWEN, 1865, FROM THE LOWER CRETACEOUS OF MORELLA (CASTELLÓN, SPAIN). Isolated dermal armour elements of an ankylosaur from the lower Aptian Arcillas de Morella Formation at Morella (Castellón, Spain) are described herein. These elements are presacral and caudal spines, fragments of sacropelvic shield, keeled scutes and keeled ossicles. The possession of ungrooved presacral spines and a sa-cropelvic shield composed of irregularly arranged bosses and small tubercles are some of the features shared with Polacanthus. Thus we tentatively refer these elements to Polacanthus sp. This assemblage of Polacanthus dermal armour elements is currently the most important outside England. Furthermore, the new evidence of this ankylosaur in the Iberian record corroborates the great similarity between the Barremian—Aptian dinosaur faunas both the British and Iberian records.
... It yielded Mantell's original Iguanodon material during the 1820s, the armoured dinosaur Hylaeosaurus armatus during the 1830s, the earliest sauropod discoveries during the 1840s, and what proved to be a pivotal form in early ideas on the evolutionary relationship between dinosaurs and birds, Hypsilophodon, in 1869. Despite the fact that Wealden exposures have been well explored and extensively studied since the early 1800s, they continue to yield new dinosaurs, with recently described taxa including the spinosauroid Baryonyx walkeri (Charig & Milner 1986), the ankylosaur Polacanthus rudgwickensis (Blows 1996), the allosauroid Neovenator salerii (Hutt et al. 1996), the basal tyrannosauroid Eotyrannus lengi (Hutt et al. 2001), the extremely unusual neosauropod Xenoposeidon proneneukos (Taylor & Naish 2007) and a large (as yet unnamed) tetanuran theropod of uncertain affinities (Benson et al. 2009). ...
Article
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Saurischian dinosaurs were pneumatic animals. The presence of invasive skeletal foramina leading to large internal chambers within the skeleton strongly indicate the presence of avian-style skeletal pneumaticity of the skeleton in sauropodomorphs and non-avian theropods. While the hypothesis of skeletal pneumaticity has undergone a renaissance in recent years, it was initially promoted during the late 1800s after dinosaur fossils from the English Lower Cretaceous Wealden Supergroup led Richard Owen and Harry Seeley to note the pneumatic, bird-like features of the vertebrae they described (Hermann von Meyer had also briefly alluded to skeletal pneumaticity in dinosaurs during the 1830s). In describing the theropod Becklespinax altispinax from the Hastings Beds Group (at the time referred to Megalosaurus), Richard Owen proposed that the laminae on the neural arch served to house 'parts of the lungs'. He evidently imagined Becklespinax to exhibit avian-style post-cranial skeletal pneumaticity. In 1870 Harry Seeley described two sauropod vertebrae from the Wealden Supergroup, naming them Ornithopsis hulkei. Contrary to what is often stated, Seeley did not identify Ornithopsis as a pterosaur, but as an animal that might 'bridge over' the gap between birds and pterosaurs, while at the same time having some affinity with dinosaurs. The lateral foramina and internal bony cavities of one of these specimens were regarded by Seeley as allowing 'the prolongation of the peculiarly avian respiratory system into the bones', and he emphasized 'the lightest and airiest plan' of the specimen. In 1876 Owen described the Wessex Formation sauropod Chondrosteosaurus gigas. While regarding the lateral fossae as probably having 'lodged a saccular process of the lung', Owen now took the opportunity to attack Seeley's claims of pneumaticity in Ornithopsis, arguing that the internal cavities in Chondrosteosaurus 'were occupied in the living reptile by unossified cartilage, or chondrine'. The name Chondrosteosaurus gigas ('giant cartilage and bone lizard') also looks like a direct assault on Seeley's proposal of a pneumatic vertebral interior. Owen's actions seem odd given that he was familiar with the internal morphology of avian vertebrae (which are often strikingly similar to those of sauropods). However, both authors have proved insighful in correctly identifying skeletal pneumaticity during this early phase of dinosaur research. A thorough historical review of early ideas on dinosaurian pneumaticity is still required.
... This result suggests that the 'polacanthids' represent early stages of the nodosaurid radiation, and this accords with pre-cladistic conceptions of these taxa (Coombs 1971(Coombs , 1978Coombs & Maryanska 1990;Blows 1987Blows , 1996. Coombs (1978;Coombs & Maryanska 1990) synonymized Polacanthus and Hylaeosaurus and considered the remains to represent a primitive nodosaurid. ...
Article
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Ankylosauria is a diverse clade of quadrupedal ornithischian dinosaurs whose remains are known from Middle Jurassic to latest Cretaceous sediments worldwide. Despite a long history of research, ankylosaur interrelationships remain poorly resolved and existing cladistic analyses suffer from limited character and taxon sampling. Here, we present the most comprehensive phylogenetic analysis of the group attempted to date. The traditional ankylosaurid–nodosaurid dichotomy is maintained. Ankylosauridae forms a well-resolved clade, which includes Zhongyuansaurus, the first ankylosaurid known to lack a tail club. Nodosauridae includes a number of taxa that were resolved either as ‘polacanthids’ or basal ankylosaurids in previous analyses. The use of a broader character sample allows analysis of the interrelationships of all valid ankylosaur species; this has revealed several previously unrecognized relationships. Stegosauria is recovered as the sister taxon to Ankylosauria, while Scelidosaurus is found to be a basal thyreophoran. Dedicated methods for coding continuous characters could be used in future to improve the resolution of ankylosaur phylogeny, particularly in order to explore the relationships within the poorly resolved nodosaurid clade.
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A report of a talk on Wealden ornithischian (‘bird-hipped’) dinosaurs given by Dr Paul Barrett (Natural History Museum) to the Hastings & District Geological Society (18th November 2012). It also includes some additional notes from other sources, including a 19th century unpublished manuscript by Mr W.H. Bensted, owner of the quarry where the Maidstone Iguanodon (or Mantell-piece) was found. The manuscript was donated to Maidstone Museum in 2002. Reference: Austen, P.A. 2013. Wealden ornithischian (‘bird-hipped’) dinosaurs. Hastings & District Geological Society Journal, 19, 6–17.
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Hastings & District Geological Society Journal, Vol.19, December 2013 (Low Resolution) CONTENTS: 2013 Officials and Committee . . . p.1 // Minutes of the AGM – 9th December 2012 . . . p.2 // HDGS Barbecue - Sunday, 11th August 2013 . . . p.4 // Statement of Income & Expenditure and Balances for the Year Ending 31st December 2012 . . . p.5 // Wealden ornithischian (‘bird-hipped’) dinosaurs - by Peter Austen . . . p.6 // The West Coast Fossil Park, Western Cape, South Africa - by Margaret A Dale . . . p.18 // Antelope Canyon - by Jim Priestley . . . p.19 // Booth Museum yields big ankylosaur surprise - by Andy Ottaway . . . p.22 // Report on the visit by a group of HDGS members to University College London - by Jim Simpson . . . p.24 // Sussex Mineral Show - Saturday, 15th November 2014 . . . p.31 // David Brockhurst – Royal Mail’s Stamp of Approval! - by Peter Austen . . . p.32 // Geologists’ Association Field Meetings - 2014 . . . p.33 // HDGS/GA field meeting: Cliff End to Fairlight - by Peter Austen, Ken Brooks and Ed Jarzembowski . . . p.34 // Dinosaur found at Bexhill - by Peter and Joyce Austen . . . p.36 // Miss Marian Frost and her ‘Geological Literature of Sussex’ - by Anthony Brook . . . p.38 // Websites - by Peter Austen . . . p.47 // The Marsh Award for Palaeontology 2013 - by Diana Brooks . . . p.48 // The Arthur Smith Woodward 150th Anniversary Symposium – 21st May 2014 - by Mike Smith . . . p.50 // Coming soon - Geology and Fossils of the Hastings Area (Second edition) . . . p.52 // Geology and History in Southeast England – GA Regional Conference - Anthony Brook . . . p.52 // Palaeontology in the News - edited by Peter Austen . . . p.53 // Postcards from the Past . . . p.63.
Article
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Ankylosaurian dermal armour elements from the Fuente Espudia locality, near Salas de los Infantes (Burgos Province), are described. These remains have been recovered from red clays of the Urbion Group, which belong to the Weald facies of the western Cameros Basin, of possible Barremian-Aptian age (Lower Cretaceous). Based on their general form, two caudal spines are here assigned to the nodosaurid Polacanthus. This represents the first mention of this genus in the Iberian Peninsula. Previous finds in the same area could also be assigned to this armoured dinosaur.
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Distal humerus morphology in Thyreophora. (PDF)
Ankylosaur material from the upper Lower Cretaceous to lower Upper Cretaceous (Albian-Cenomanian) of south-eastern England is reviewed systematically. 'Acanthopholis horridus' from the Lower Chalk of Folkestone (Kent) is regarded as a nomen dubium. A re-evaluation of the ankylosaur specimens from the Cambridge Greensand (mostly probably reworked from the underlying Gault Clay) suggests that all of the species of 'Acanthopholis' erected by Seeley, on the basis of fragmentary, and often composite, non-diagnostic material, are invalid. Anoplosaurits curtonotus Seeley is removed from the Ornithopoda, and provisionally regarded as a valid taxon of nodosaurid ankylosaur. A lectotype, a partial scapula, is designated for this species. Anoplosaurus appears to be a relatively primitive nodosaurid which retains several plesiomorphic features in the lower jaw, sacrum and appendicular skeleton.
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The disappearance of nonavian dinosaurs is only a small part of a greater class of extinctions known as “mass extinctions.” Mass extinctions are global events characterized by unusually high rates of extinction. The five episodes of mass extinctions in Earth history are the Permo-Triassic extinction, the Late Ordovician extinction, the Late Devonian extinction, the Triassic-Jurassic extinction, and the Cretaceous-Tertiary (K/T) extinction. This chapter focuses on patterns of geologic and biotic changes that occurred during the Cretaceous-Tertiary (K/T) extinction. It also highlights the similarities and differences in interpretations of geologic and fossil records. It concludes with two scenarios explaining the differing views about dinosaur extinction.
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Metatetrapous valdensis Nopcsa, 1923 from the late Berriasian of northwestern Germany was the first dinosaur ichnotaxon ever attributed to a thyreophoran trackmaker. However, the subsequent lost of the original material made this identification and the status of the ichnotaxon questionable for many subsequent authors. This situation was aggravated by the fact that there are only very brief original descriptions accompanied by a single drawing. A reconsideration of the original description recognizes M. valdensis as a valid ichnotaxon, which, albeit showing great resemblance in pes morphology to similar ichnotaxa, stands out from them by a tetradactyl manus. It not only holds its original systematic attribution, but also has sparked early hypotheses on the phylogeny of dinosaurs already in 1922, possibly for the first time based upon tracks. Two surviving natural hypichnial casts of ankylosaurian pes imprints from the same stratum cannot be straightforwardly identified with the type material due to a lack of documentation. However, comprehensive circumstantial evidence, including complete accordance in size and morphology among others, strongly supports such an association. The tracks confirm the presence of ankylosaurs in this lacustrine-deltaic setting as a very rare element of the local dinosaur fauna.
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The Zorralbo locality of the eastern Cameros Basin, near Soria, Spain, has produced a diverse dinosaur assemblage from the Lower Cretaceous Golmayo Formation. Ankylosaurs are represented by dorsal vertebrae and ribs, a fragmentary sacrum and ilium, and several types of dermal armour. Most, if not all, of the material probably belongs to a single medium to large-sized adult individual. The Soria remains are referred to Polacanthus on the basis of the presence of conical, ungrooved presacral spines, a sacropelvic shield composed of irregularly arranged bosses and small tubercles, large spined plates, and hollow-based triangular caudal plates with an extended posterior basal edge and a pointed spine. Polacanthus is well known from the Wealden Group (Barremian-Aptian) of the Isle of Wight and from the Weald Clay Group of West Sussex (England). In addition, isolated remains have been reported from the penicontemporaneous formations of the Iberian Peninsula. The Soria outcrop is currently the most productive Polacanthus site outside England. Moreover, it has yielded the oldest record (late Hauterivian to basal Barremian according to charophyte association) of this ankylosaur known to date in Europe. Minor anatomic differences between the Soria material and the taxa P. foxii (type-species) and P. rudgwickensis suggest the presence of a third species of Polacanthus in the Iberian Peninsula, but additional material is needed to confirm this interpretation.
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Ankylosaurian dermal armour elements from the Fuente Espudia locality, near Salas de los Infantes (Burgos Province), are described. These remains have been recovered from red clays of the Urbion Group, which belong to the Weald facies of the western Cameros Basin, of possible Barremian-Aptian age (Lower Cretaceous). Based on their general form, two caudal spines are here assigned to the nodosaurid Polacanthus . This represents the first mention of this genus in the Iberian Peninsula. Previous finds in the same area could also be assigned to this armoured dinosaur. Se describen elementos dermatoesqueléticos de un anquilosaurio procedentes del yacimiento de Fuente Espudia, cerca de Salas de los Infantes (Burgos). Los restos fósiles se localizan en arcillas rojas del Grupo Urbión, que forman parte de las facies Weald del sector occidental de la Cuenca de Cameros, de posible edad Barremiense-Aptiense (Cretácico inferior). Dos espinas proceden de la región caudal y, por su forma general, se atribuyen al nodosáurido Polacanthus . Se trata de la primera cita de este género en la Península Ibérica. Hallazgos previos en el mismo área pueden también asignarse a este dinosaurio acorazado.
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The geographic range of the nodosaurid ankylosaur Polacanthus (Ornithischia), from the Wealden beds (Lower Cretaceous, Barremian) of the Isle of Wight (England), is extended to the Lakota Formation of South Dakota (USA). The suggested synonymy of Hoplitosaurus with Polacanthus is confirmed on the basis of femoral features. The transatlantic distribution of Polacanthus supports previous evidence for a land connection between Europe and North America during the Early Cretaceous. There is an abridged English version. -English summary
Article
A partial nodosaurid ankylosaur skeleton from Lower Cretaceous littoral deposits of Texas represents a new genus and species, Texasetes pleurohalio. It is distinguished by a prong-like scapular spine that is directed toward the innermost point of the glenoid, development of a small prespinous fossa, and retention of a splint-like fourth trochanter on the femur. Preservation in marginal marine deposits is not indicative of normal habitat preferences. T. pleurohalio is more advanced than Hoplitosaurus marshi, and the latter may be the most primitive nodosaurid for which a considerable part of the specimen is known. The proposed synonymy of Hoplitosaurus and Polacanthus is rejected.
Article
Three classifications of the Dinosauria have been proposed, which differ from each other in the principles on which their authors proposed to make the divisions. First in time is Professor Cope’s classification (‘Philadelphia, Acad. Nat. Sci. Proc.,’ November 13th, 1866, and December 31st, 1867; ‘Amer. Phil. Soc. Trans.,’ vol. 14, Part I). He relied upon the characters of the tarsus and the ilium; and on their varied condition divided Dinosaurs into three orders named Orthopoda, Goniopoda, and Symphopoda. In the Orthopoda , the generic types associated are Scelidosaurus, Hylæosaurus, Iguanodon, and Hadrosaurus. And in this group the relations of the tibia and fibula are compared to those of modern Lizards, the proximal tarsals being distinct from each other and from the tibia. The ilium has a narrowed anterior prolongation.
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The author describes the large dorsal shield, which has been recently restored and now exhibits the grouping of the keeled and tuberculated fragments, which in their disconnected and scattered condition had formerly been regarded as portions of separate scutes. This unique specimen shows Polacanthus to have possessed a more complete dermal armature than any other Dinosaur yet described.
For the opportunity of studying the remains described in this note I am indebted to the courtesy of the Rev. W. Fox, of Brixton, Isle of Wight, who last autumn gave me free access to his rich collection of fossils obtained in that locality. Much shattered by being very hastily dug out, and since much damaged by the accidental breakages and the dissociations scarcely avoidable in the absence of a suitable place for their safe-keeping, there is risk of these remains becoming before long lost to the palæontologist. In view of this not improbable eventuality I venture to offer to the Royal Society these notes, in writing which I have been reminded that it was to this Society the late Dr. G. A. Mantell, now more than fifty years since, communicated his first discoveries of Iguanodont and Hylæosaurian remains.
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Some time since, my colleague, Dr. Percy, purchased from Mr. Griffiths, Some of Folkestone, and sent to me, certain fossils from the Chalk-marl near that town, which appeared to possess unusnal characters. On examining them I found that they were large scutes and spines entering into the dermal armour of what, I did not doubt, was a large reptile allied to Soelidosaurus, Hylœosaurus , and Polacanthus . I therefore requested Mr. Griffiths to procure for me every fragment of the skeleton which he could procure from the somewhat inconvenient locality (between tide-marks) in which the remains had been found, and I eventually succeeded in obtaining three teeth, with a number of fragments of the vertabræ, part of the skull and limb-bones, besides a large additional quantity of scutes. I am still not without hope of recovering other parts of the skeleton; but as the remains in my hands are sufficient to enable me to form a tolerably clear notion of the animal's structure, a brief notice of its main features will probably interest the readers of the Geological Magazine.
Article
This note reports the discovery of a new dinosaursoutcrop in Salas de los Infantes (province of Burgos, Spain), belonging to the Lower Cretaceous (Barremian-Albian). The main piece found up to date is a dermal spike from an ankylosaur dinosaur. The ratio between the maximum basal dimension to the height and the outline of the cross-section of the blade seem to indicate it belongs to the Nodosauridae. Several structural (and perhaps textural too) characteristics (as the disposition and morphlogy of the spike's base) seem to indicate that this Spanish nodosaurid could be close to Hylaeosaurus.RésuméCette note rapporte la découverte d'un nouveaugisement à dinosauriens dans le Crétacé Inférieur (Barrémien-Albien) de Salas de los Infantes (province de Burgos, Espagne). La pièce principale trouvée pour le moment est une épine dermique appartenant à un dinosaurien ankylosaurien. Le rapport entre la plus grande dimension de la base et la hauteur, ainsi que le contour de la section de l'épine, semblent indiquer son appartenance aux Nodosauridae. Diverses caractéristiques structurales (et peut être aussi de la texture) comme la disposition et la morphologie de la base de l'épine, semblent indiquer que ce nodosauridé espagnol est probablement proche de Hylaeosaurus.
Article
Two genera of armoured dinosaurs (Ankylosauria) are present in the Lower Cretaceous Wealden Beds of England. Polacanthus Owencan be distinguished from Hylaeosaurus Mantell on the basis of significant differences in the pectoral girdle, hindlimb and dermal armour. A comprehensive review of the dinosaurs from the Wealden Series of England and contemporary basins of western Europe adds further evidence of a biologicalseparation between Lower Wealden (Hastings Beds, containing Hylaeosaurusarmatus) and Upper Wealden faunas (Wealden Group of the Isle of Wight-containing Polacanthus foxii-and nearly equivalent units in Belgium, France, Germany and Spain).
Wealden dinosaur biostratigraphy Two Lower Cretaceous dinosaurs of Mongolia
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NORMAN, D. B. 1987. Wealden dinosaur biostratigraphy. In Fourth Symposium on Mesozoic Terrestrial Ecosystems (eds P. J. Currie and E. H. Koster), pp. 165-70. Short papers, Drumheller, Canada. OSBORN, H. F. 1923. Two Lower Cretaceous dinosaurs of Mongolia. American Museum Novitates, no. 95,1-10.
On the anatomy of Iguanodon atherfield-ensis (Omithischia: Ornithopoda) Bulletin de I
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NORMAN, D. B. 1986. On the anatomy of Iguanodon atherfield-ensis (Omithischia: Ornithopoda). Bulletin de I'Institut Royal des Sciences Naturelles de Belgique (Sciences de la Terre) 56,281-372.