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1.
Tamara van den Berg David I. Whiteside Pedro Viegas Remmert Schouten Michael J. Benton 《Proceedings of the Geologists' Association. Geologists' Association》2012,123(4):638-648
The Late Triassic fissure fills from the region of Bristol, SW England and S Wales, preserve unique assemblages of small vertebrates derived from an archipelago of palaeo-islands that document aspects of a critical transition in the history of terrestrial ecosystems. Tytherington Quarry, in south Gloucestershire, is the site of several fossiliferous fissures, all dated as Rhaetian (terminal Triassic), and source of abundant remains of the ‘Bristol dinosaur’, Thecodontosaurus antiquus. In addition, the fissure sediments have yielded previously unreported microvertebrate assemblages, including over 400 jaw remains from three genera of sphenodontians and 100 archosaur teeth assigned to 15 morphotypes. The land fauna is dominated by sphenodontians, with Diphydontosaurus by far the most common form, followed by Clevosaurus, then the sauropodomorph dinosaur Thecodontosaurus, and then the sphenodontian Planocephalosaurus. There are, in addition, rare remains of contemporaneous bony fishes, as well as fossils apparently reworked from the Carboniferous limestones, namely conodonts, holocephalian (chimaeroid) teeth, and a shark tooth. Many typical latest Triassic animals, such as temnospondyls, phytosaurs, aetosaurs, rauisuchians, plateosaurids and dicynodonts are not represented at Tytherington, perhaps because these generally larger animals did not live on the palaeo-island, or because their carcasses could not fit into the fissures. The absence of tritylodonts and early mammals is, however, less easy to explain on the basis of size, although it is known that these forms were abundant here by the Early Jurassic. 相似文献
2.
Davide Foffa David I. WhitesidePedro A. Viegas Michael J. Benton 《Proceedings of the Geologists' Association. Geologists' Association》2014
Since the discovery of the basal sauropodomorph dinosaur Thecodontosaurus in the 1830s, the associated fauna from the Triassic fissures at Durdham Down (Bristol, UK) has not been investigated, largely because the quarries are built over. Other fissure sites around the Bristol Channel show that dinosaurs represented a minor part of the fauna of the Late Triassic archipelago. Here we present data on microvertebrates from the original Durdham Down fissure rocks, which considerably expand the taxonomic diversity of the island fauna, revealing that it was dominated by the sphenodontian Diphydontosaurus, and that archosauromorphs, including sphenosuchian crocodylomorphs, coelophysoid theropods, and the basal sauropodomorph Thecodontosaurus, were diverse. Importantly, a few fish teeth provide new information about the debated age of the fissure deposit, which is identified as lower Rhaetian. Thecodontosaurus had been assigned an age range over 20–25 Myr of the Late Triassic, so this narrower age determination (209.5–204 Myr) is important for studies of early dinosaurian evolution. 相似文献
3.
Robbert Folmer Stephen K. Donovan 《Proceedings of the Geologists' Association. Geologists' Association》2021,132(1):102-109
Salthill Quarry, Clitheroe, Lancashire (Mississippian, Visean) is a Site of Special Scientific Interest (SSSI), in part based on its diverse fauna of invertebrates, particularly echinoderms. A small collection of crinoid pluricolumnals are described herein, collected from muddy horizons in the Hodder Mudstone Formation to typify the diversity and frequency of their encrusting and boring fauna. These specimens are infested by a range of episkeletozoans, namely a single occurrence of Sutherlandia parasitica (Phillips), four occurrences of Cladochonus sp. and eight of Oichnus paraboloides Bromley. Two variants of the pit (boring or embedment or both) O. paraboloides are recognised: those in which a living crinoid showed a growth reaction to pit formation; and those that did not and which were presumably dead at the time of infestation. The epizoozoan tabulate coral Cladochonus sp. is also common, including specimens intergrown between and within the columnals. Sutherlandia parasitica is relatively uncommon; the only specimen likely infested a dead pluricolumnal on the sea floor. A comparative collection of pluricolumnals infested by Cladochonus beecheri Grabau from the Mississippian Borden Group of the Midwest, USA, showed superior preservation to the Clitheroe Cladochonus sp. Cladochonus beecheri in the Borden Group infested platycrinitid crinoid stems, an association not noted from Salthill Quarry. Similar suites of borings-episkeletozoans, from two other sites – the Visean of Feltrim, Co. Dublin, Ireland, and the Permian of Timor – suggest that these were persistent associations for much of the Late Palaeozoic. 相似文献
4.
Li-Da Xing Jin Ba Martin G.Lockley Hendrik Klein Sheng-Wu Yan Anthony Romilio Chun-Yong Chou W.Scott Persons IV 《古地理学报》2018,(1)
Upper Triassic and Middle Jurassic strata of the Xichang Basin in Sichuan Province, southwestern China, yielded important dinosaur ichnofossils. From the Xujiahe Formation of the Yiguojiao tracksite, we report a Late Triassic footprint assemblage in China and the first discovery of diagnostic Triassic sauropodomorph tracks in this region. The tracks share a number of features in common with the ichnogenera Eosauropus(Late Triassic) and Liujianpus(Early Jurassic). The neighboring Bingtu tracksite is stratigraphically younger(Shaximiao Formation, Middle Jurassic) and preserves small tridactyl theropod tracks that represent the first occurrence of the ichnotaxon Carmelopodus in China and Asia. While these tracks are morphologically comparable to those from the Middle Jurassic type locality in North America, the specimens from China show the proximal margin of the digit IV impression in a more cranial position, which may indicate a trackmaker with a relatively short metatarsal IV. In addition to the skeletal record, the Carmelopodus footprints document the presence of small theropods in the dinosaur fauna of the Middle Jurassic Shaximiao Formation. 相似文献
5.
David I Whiteside Christopher J. Duffin 《Proceedings of the Geologists' Association. Geologists' Association》2021,132(1):34-49
We describe here new Late Triassic haramiyidan mammaliaform and reptile fossils from near the classic ‘Microlestes’ Quarry’ at Holwell, Somerset, U.K., where Charles Moore discovered a huge collection of microvertebrates in the 1850s. Moore’s discoveries included the haramiyid Thomasia (formerly ‘Microlestes’ and Microcleptes) for which he achieved worldwide fame. Subsequently, despite much fossicking by researchers at Holwell, few new identifiable specimens of mammaliamorphs and lepidosaurs have been recorded and these were by Kühne in 1939. The new finds described here from a bedded sequence, not from a fissure, add significantly to our knowledge of the Holwell tetrapods and to the Rhaetian terrestrial faunas of the SW U.K. Our discovery of haramiyidan teeth includes a previously unknown type of Theroteinus, a genus not previously recorded from outside of the St-Nicholas-de-Port locality in France. An archosaur tooth, possibly from a phytosaur, is also recorded. The new lepidosaur specimens add significant detail to the recently described ‘basal’ rhynchocephalian Penegephyrosaurus curtiscoppi as well as demonstrating that the global diversity of Lepidosauria in the Late Triassic remains incompletely known. 相似文献
6.
An incomplete skull (SMNS 12352) from the Norian (Late Triassic), found at the same locality (Pfaffenhofen, Germany) as Procompsognathus triassicus, has previously been attributed to either a theropod or a crocodylomorph. The specimen is partially embedded in matrix and, therefore, was CT scanned so that the concealed portion could be visualized and a 3D model could be printed by means of rapid prototyping. Mainly based on the separation between the nasal and the antorbital fossa, the skull likely pertains to an indeterminate basal crocodylomorph (non-Crocodyliformes), which is, however, distinct from Saltoposuchus connectens. 相似文献
7.
The North American fossil record of dinosaur eggshells for the Cretaceous is primarily restricted to formations of the middle (Albian–Cenomanian) and uppermost (Campanian–Maastrichtian) stages, with a large gap in the record for intermediate stages. Here we describe a dinosaur eggshell assemblage from a formation that represents an intermediate and poorly fossiliferous stage of the Upper Cretaceous, the Santonian Milk River Formation of southern Alberta, Canada. The Milk River eggshell assemblage contains five eggshell taxa: Continuoolithus, Porituberoolithus, Prismatoolithus, Spheroolithus, and Triprismatoolithus. These ootaxa are most similar to those reported from younger Campanian–Maastrichtian formations of the northern Western Interior than they are to ootaxa reported from older middle Cretaceous formations (i.e., predominantly Macroelongatoolithus). Characteristics of the Milk River ootaxa indicate that they are ascribable to at least one ornithopod and four small theropod species. The taxonomic affinity of the eggshell assemblage is consistent with the dinosaur fauna known based on isolated teeth and fragmentary skeletal remains from the formation, although most ornithischians and large theropods are not represented by eggshell. Relative to the Milk River Formation eggshell, similar oospecies occurring in younger Cretaceous deposits tend to be somewhat thicker, which may reflect an increase in body size of various dinosaur lineages during the Late Cretaceous. 相似文献
8.
A relatively low diversity coral fauna comprising eight zooxanthellate, three azooxanthellate, and one unidentified species is described from a Late Cretaceous rocky shore at Ivö Klack, southern Sweden. All species, except the solitary azooxanthellate Paracyathus? sp., are represented by one or two specimens only, indicating low preservation potential similar to the aragonite-shelled gastropod fauna from the same locality. The fauna comprises one out of two northernmost zooxanthellate forms known and adds important environmental information to the fauna and depositional conditions of the rocky shore at Ivö Klack. 相似文献
9.
Multivariate analysis is used to differentiate shape variations between ichnites of theropod and ornithopod dinosaurs. Tracks of an alleged theropod cf. Tyrannosauropus from the mid-Cretaceous (late Albian-Cenomanian) Winton Formation of Lark Quarry, central-western Queensland, Australia were examined and foot shape ratios calculated. Multivariate analysis of these shape variables indicates this track-maker was an ornithopod dinosaur. A strong morphological similarity exists between the Lark Quarry ichnites and those of the iguanodontian ichnotaxon Amblydactylus gethingi. Considering the grade of ornithopod this ichnogenus is thought to represent (a non-hadrosaurid styracosternan) and the age and geography of Lark Quarry, we suggest that the track-maker may have been a dinosaur similar to Muttaburrasaurus langdoni. 相似文献
10.
Peter M. Galton 《Swiss Journal of Geoscience》2010,103(2):187-198
Stegosaurus armatus Marsh 1877, based on a partial tail and a very large dermal plate from the Morrison Formation (Late Jurassic) of Morrison, Wyoming, USA, is a nomen dubium. Valid Morrison stegosaur species (with possible autapomorphies, dermal “armor” considered if present), with most holotypes consisting of a disarticulated partial postcranial skeleton at most, include: Hypsirhophus discurus Cope 1878 (characters of incomplete vertebrae, a dorsal and a caudal; Garden Park near Cañon City, Colorado); Stegosaurus ungulatus Marsh 1879 (half skeleton with partial skull; three pairs of small flat dermal spines adjacent to terminal tail spikes; Quarry 12, Como Bluff near Como station, Wyoming; syntype is holotype of S. duplex Marsh 1887, half skeleton lacking armor; Quarry 11, Como Bluff); Diracodon laticeps Marsh 1881b (just partial dentaries with few teeth, diastema between predentary and tooth 1; Quarry 13, Como Bluff); Stegosaurus sulcatus Marsh 1887 (pair of ?tail spikes with greatly enlarged base; Quarry 13, Como Bluff); S. longispinus Gilmore 1914 (characters of distal caudal vertebrae, tail spikes: two pairs, sub-equal bases, transversely flattened, very elongate; Alcova, Wyoming); and Hesperosaurus mjosi Carpenter, Miles &; Cloward, 2001 (?Stegosaurus mjosi; partial articulated skeleton with skull, no limbs, several plesiomorphic and autapomorphic characters, dorsal plates longer than tall; Wyoming). However, the well known valid nominal species, S. stenops Marsh 1887 (12 autapomorphies, three alternating flat plates adjacent to terminal tail spikes; Garden Park), is based on a virtually complete articulated skeleton lacking only the terminal caudal vertebrae and first pair of tail spikes. It includes 17 dermal plates, is still exposed as preserved on the block, and is the current basis for Stegosaurus. The International Commission on Zoological Nomenclature (ICZN) will be petitioned to designate S. stenops Marsh 1887 as the new type species of Stegosaurus Marsh 1877 in order to conserve Stegosauria Marsh 1877 and Stegosauridae Marsh 1880 (also Stegosauroidea, Stegosaurinae). 相似文献
11.
Hassan A. Soliman Nageh A. Obaidalla Amr A. Metwally Azza A. Mohamed 《Arabian Journal of Geosciences》2018,11(14):394
Benthic foraminiferal fauna are analyzed quantitatively and qualitatively at three stratigraphic sections in Eastern Desert of Egypt (Serai, Duwi, and Um El Huetat). These sections embrace the Paleocene–Eocene Thermal Maximum (PETM) interval which is represented by the occurrence of five distinctive beds. These beds constitute the Dababiya Quarry Member at the lower part of Esna Formation. The occurrence of them indicates an expanded and relatively continuous record across the P/E boundary. The organic-rich clay layer (bed no. 1 of the Dababiya Quarry Member) marks the start of the PETM event. This bed is characterized by the extinction of all benthic foraminiferal fauna except for the occurrence of rare agglutinated foraminiferal species. The presence of these species indicates an oceanic anoxic event at the sea floor. High concentration of phosphatic contents including fish remains occurred in the middle part of the PETM (bed nos. 2 and 3 of the Dababiya Quarry Member) with the continuous absence of benthic foraminiferal fauna except for few specimens at the top of bed 3. Bed nos. 4 and 5 of the Dababiya Quarry Member represent the upper part of the PETM and the initial stage of sea floor recovery. Low diversity and abundance of benthic foraminiferal taxa occurred within these beds, represented by Valvulineria scrobiculata, Lenticulina midwayensis, Loxostomoides appliane, and Siphogenerinoides eleganta. This phenomenon continues upward during the post-PETM event. The Paleocene velasco-type benthic foraminifera Angulogavelinella avnimelechi and Coryphostoma midwayensis species are extinct within the advent of the PETM event. The benthic foraminiferal assemblages at the studied sections are dominated by midway-type fauna with little representative of velasco-type fauna. The velasco-type species are represented with high abundance at Serai section and with low densities at Um El Huetat section, while at Duwi section, they rarely occurred. This suggests outer neritic-upper bathyal (150–400 m) setting at Serai section and mostly middle-outer neritic (50–150 m) setting at Um El Huetat and Duwi sections. 相似文献
12.
13.
The fossil specimens discussed in this paper were collected from the grayish green mudstone and shale in the upper part of Lower Member of Middle Triassic Tongchuan Formation (T2t) in Shaanxi Province, China. Venationary feature correlation with old families and taxonomic discussion show that, among them, one specimen can be assigned to a new family - Sunopteridae fam. nov., which includes a new genus and species and can be referred to Order Protorthoptera Handlirsch, 1906 in taxonomic position, thus belonging to a new member of the Tongchuan Entomoassemblage of Shaanxi Entomofauna (belonging to Shaanxi Biota). The discovery of the new family and its new genus and species has certain reference values as follows: ① The discovery of the new family and its new genus and species fills firstly the vacancy in the protorthopterous field of China; ② In the meantime, it fills also the gaps of the valuable Middle Triassic protorthopterous fossil specimens between Late Carboniferous and Late Triassic Epochs in the world; ③ Judging from venationary features and taxonomic position, especially in the course of the formation of the merged vein of M and Cu, it formed a new unique and particular style of merged vein M+Cu. It not only is unique and simple, but also can be distinguished from the above mentioned 10 old families, thus providing important taxonomic evidence. 相似文献
14.
Grzegorz Nied?wiedzki Tomasz SingerGerard D. Gierliński Martin G. Lockley 《Cretaceous Research》2012,33(1):7-10
The Djadokhta Formation of the Gobi Desert is known for the number and diversity of dinosaur and other vertebrate bones and skeletons found there, but only theropod, hadrosaur and supposed ankylosaurid footprints have been reported from this stratum. Dinosaur footprints are also noted from the Nemegt Formation, and occur as typical dinosaur track accumulations (tracksites). An articulated protoceratopsid skeleton - specimen ZPAL Mg D-II/3 - was collected by the Polish-Mongolian Expedition of 1965 from the Djadokhta Formation of Flaming Cliffs in Mongolia. Recently, the natural cast of a tetradactyl digitigrade footprint was found underneath the pelvic girdle while the skeleton and matrix were being prepared. This is possibly the first find of a dinosaur track in close association with an articulated skeleton. Although Protoceratops is an extremely common dinosaur in Mongolia, its footprints have never previously been reported from the Late Cretaceous of the Gobi Desert. 相似文献
15.
During the latest Cretaceous, distinct dinosaur faunas were found in Laurasia and Gondwana. Tyrannosaurids, hadrosaurids, and ceratopsians dominated in North America and Asia, while abelisaurids and titanosaurians dominated in South America, India, and Madagascar. Little is known about dinosaur faunas from the latest Cretaceous of Africa, however. Here, a new abelisaurid theropod, Chenanisaurus barbaricus, is described from the upper Maastrichtian phosphates of the Ouled Abdoun Basin in Morocco, North Africa on the basis of a partial dentary and isolated teeth. Chenanisaurus is both one of the largest abelisaurids, and one of the youngest known African dinosaurs. Along with previously reported titanosaurian remains, Chenanisaurus documents the persistence of a classic Gondwanan abelisaurid-titanosaurian fauna in mainland Africa until just prior to the end-Cretaceous mass extinction. The animal is unusual both in terms of its large size and the unusually short and robust jaw. Although it resembles South American carnotaurines in having a deep, bowed mandible, phylogenetic analysis suggests that Chenanisaurus may represent a lineage of abelisaurids that is distinct from those previously described from the latest Cretaceous of South America, Indo-Madagascar, and Europe, consistent with the hypothesis that the fragmentation of Gondwana led to the evolution of endemic dinosaur faunas during the Late Cretaceous. 相似文献
16.
Li XuYoshitsugu Kobayashi Junchang LüYuong-Nam Lee Yongqing LiuKohei Tanaka Xingliao ZhangSonghai Jia Jiming Zhang 《Cretaceous Research》2011,32(2):213-222
A partial skeleton of the ornithomimid dinosaur, discovered from the Late Cretaceous Qiupa Formation of Luanchuan County, Tantou Basin, Henan Province, China, is described here and assigned to a new genus and species, Qiupalong henanensis, with unique features (a notch on the lateral surface of the lateral posterior process of the proximal end of tibia and a small pit at the contact between astragalus and calcaneum). A phylogenetic analysis in this study suggests that it is a derived ornithomimid and form a monophyly with North American ornithomimids (Struthiomimus altus and Ornithomimus edmontonicus), sharing two characters (straight pubic shaft and large acute angle between pubic shaft and boot). Some characters (small anterior process of the pubic boot and curved pedal unguals) are seen in basal ornithomimosaurs as well, but these features in Q. henanensis are reversal. Qiupalong is the first definitive ornithomimid from outside of the Gobi Desert and is the southern-most occurrence of Late Cretaceous ornithomimid from eastern Asia, demonstrating southern extension of ornithomimid distribution in Asia. 相似文献
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18.
北京延庆千家店地区土城子组恐龙足迹点沉积环境 总被引：2，自引：2，他引：0
北京延庆千家店地区晚侏罗世土城子组化石稀少,而新发现的恐龙足迹是北京恐龙存活过的重要证据,研究其沉积环境对恢复当时恐龙动物群的生活环境具有十分重要的意义。研究区恐龙足迹主要包括兽脚类、蜥脚类和可能的鸟脚类足迹。运用地层学、岩石学、古生物学和沉积学方法,通过地层剖面、岩石薄片、足迹分布、沉积构造及详细的粒度分布特征,综合得出千家店地区土城子组三段恐龙足迹点的沉积环境,认为当时的沉积环境为含火山碎屑的浅湖沉积,恐龙足迹的赋存层位为湖滨环境。 相似文献
19.
The Lower Cretaceous (Albian) Sasayama Group in the Hyogo Prefecture of southwestern Japan has yielded various vertebrate fossils, including skeletal remains of dinosaurs, anurans, lizards, and mammals, and recently eggshell fragments. Here we report on numerous fossil eggshells from the bone-bearing Kamitaki locality in Tamba City, which represents a diverse dinosaur eggshell assemblage. Of the more than 90 eggshell fragments recovered, five different types were identified, including eggshells that likely belong to a variety of theropods (Nipponoolithus ramosus oogen. et oosp. nov., Elongatoolithus sp., Prismatoolithus sp., and Prismatoolithidae indet.) and at least one ornithopod (Spheroolithus sp.). All eggshells are relatively thin, and a new derived estimation method correlating egg mass with eggshell thickness indicates that they are among the smallest (28–135 g) theropod eggs known, likely laid by small bodied forms. The eggshell assemblage from this locality suggests that a diverse small dinosaur fauna, consisting primarily of theropods, nested in the region, a diversity yet to be evidenced from skeletal remains in Japan. 相似文献
20.
The Puesto Viejo Group crops out in the San Rafael Block, southwest Mendoza, at approximately 35° S and 68°20′ W. It consists of the basal mainly grayish Quebrada de los Fósiles Formation (QF) overlying by the reddish Río Seco de la Quebrada Formation (RSQ). The basal unit includes both plant remains (pleuromeians and sphenopsids) and vertebrates (scattered fish scales, dicynodont synapsids and remains of an archosauriform). In contrast, the RSQ beds have yielded only tetrapods, although a more diverse fauna. The latter includes cynodonts as Cynognathus, Pascualognathus and Diademodon, and also dicynodonts (Vinceria and Kannemeyeria). Based on the assemblage of tetrapod taxa the bearing levels were correlated to the Cynognathus AZ of South Africa and thus referred to the Middle Triassic (Anisian). We obtained a SHRIMP 238U/206Pb age of 235.8 ± 2.0 Ma from a rhyolitic ignimbrite interdigitated between the QF and RSQ formations at the Quebrada de los Fósiles section. This new radiometric date for the Puesto Viejo Group suggests that the tetrapod fauna in the RSQ beds existed, instead, during the Late Triassic (early Carnian) some 10 Ma later than the currently accepted age. Two scenarios might explain our results: first, the Cynognathus AZ of South Africa is wrongly assigned to the lower Middle Triassic (Anisan) and should be considered younger in age, Late Triassic (Carnian); second, the relative age of the Cynognathus AZ of South Africa is correct but the inferred range of Cynognathus and Diademodon is incorrect as they were present during the Late Triassic (Carnian) at least in South America. In any case, this new date pose serious doubts about the validity of biostratigraphic correlations based solely on tetrapod taxa, a common practice for Triassic continental successions across Gondwana. 相似文献