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1.
Here we report a large dinosaur tracksite from an extensive fluvial sandstone surface in the Lower Cretaceous Jiaguan Formation of Sichuan Province, China. The site contains over 250 individual tracks comprising at least 18 recognizable trackways, including the longest theropod trackway (cf. Eubrontes) known from China. This exceptional theropod trackway consists of 81 successive footprints covering a distance of 69 m. The tracks are well-preserved and are expressed both as true tracks on the main “upper” surface and as transmitted undertracks on a locally exposed “lower” bed. Also recorded are six other theropod trackways, including small Grallator-like ichnites, eight sauropod trackways (cf. Brontopodus), and three small ornithopod (cf. Ornithopodichnus) trackways with a parallel orientation, which may indicate gregarious behavior. Several trackways of a larger theropod trackmaker show pes imprints with elongated traces of the metatarsals, suggesting extramorphological (substrate-controlled) variation and/or plantigrade posture, which is here interpreted as indicating a change in gait assumed in response to deep and soft sediment. The assemblage indicates a diverse dinosaur fauna in the Lower Cretaceous Sichuan Basin with variously sized theropods, sauropods, and ornithopods. The late occurrence of footprints of the Grallator-Eubrontes plexus in Lower Cretaceous strata is further evidence of the extended stratigraphic range of this morphotype and the distinct palaeobiogeographic distribution of these trackmakers in East Asia. 相似文献
2.
During the Campanian and Maastrichtian ages (86–66 million years ago), tyrannosaurids were the predominant large carnivorous dinosaurs throughout the Northern hemisphere. Despite the abundance of skeletal material, the fossil-footprint record of tyrannosaurids has been limited. Here we report a tyrannosaurid trackway in the Lance Formation, Wyoming. The trackway consists of three sequential tracks on a sandstone surface. Based on the age and size of the footprints, the trackmaker can be identified as either a sub-adult Tyrannosaurus rex or a Nanotyrannus lancensis. The trackway offers a record of a tyrannosaurid pace length, which permits the speed of the trackmaker to be calculated at 4.5–8.0 km/h. This result discounts previous speculation that tyrannosaurid walking speeds were notably slower than those of other large theropods. 相似文献
3.
A partial trackway of a turtle from the Jinju Formation (Sindong Group) is the first report of Mesozoic turtle tracks from Korea and the first report of traces of an aquatic tetrapod from Korea. Six tracks show a partial trackway configuration inferred to represent a partially buoyant trackmaker, possibly engaged in “bottom walking” behavior. Although turtle tracks often co-occur with crocodylian tracks in Cretaceous coastal plain facies in other regions, especially North America, to date there are no such co-occurrences in east Asia. This suggests that in Asia paleoenvironments suitable for turtles were quite widespread, but paleoenvironments were not suitable for crocodylians. 相似文献
4.
The poor preservation and apparent monospecifity of Permian tetrapod footprints from eolian paleoenvironments have thus far hampered their reliable interpretation. This study clarifies how this is due to distinct and repeated ichnotaphonomic effects on trackway pattern and footprint morphology on originally inclined planes. Once these effects are excluded, the anatomy-consistent ichnotaxobases useful for ichnotaxonomy can be recognized. Several nomina dubia are identified, among these the ichnogenus Chelichnus, here considered a taphotaxon. The eolian ichnoassociations from the Lopingian of Scotland and Germany include six different ichnotaxa: cf. Capitosauroides isp. (?eutheriodont therapsid), Dicynodontipus geinitzi (cynodont therapsid), Dolomitipes isp. (dicynodont therapsid), Pachypes loxodactylus n. comb. (pareiasaurian parareptile), Procolophonichnium isp. (small parareptile) and Rhynchosauroides isp. (non-archosauriform neodiapsid). This is completely different from the interpretations of the last 20 years, which postulated that these paleoenvironments comprised monospecific associations of synapsid tracks. These ichnoassociations are instead moderately diverse, similar to low-latitude marginal marine to floodplain ichnoassociations and belong to the Lopingian Paradoxichnium footprint biochron. The Cornberg Formation of Germany, being constrained between the Illawarra reversal and the mid-Wuchiapingian Kupferschiefer at the Rotliegend/Zechstein transition, constitutes the earliest evidence of Lopingian tetrapod faunas at low paleolatitudes and the first evidence of low-paleolatitude faunal turnover related to the end-Guadalupian mass extinction from both the skeleton and the track record. This suggests a global extension of the dinocephalian extinction event, which occurred at high-mid (South Africa and Russia) and low (Western Europe) paleolatitudes of Pangea about 259–260 Ma and was probably triggered by the eruption of the Emeishan Large Igneous Province of SW China, which considerably changed global environmental conditions in both marine and continental settings. 相似文献
5.
Upper Cretaceous deposits in Mongolia, Chinese Inner Mongolia, and, more recently, southern China, have yielded individually rich and taxonomically diverser lizard assemblages. Here we describe the remains of a new terrestrial lizard, Asprosaurus bibongriensis gen. et sp. nov., from the Upper Cretaceous of South Korea. It represents the first record of a Mesozoic lizard from the Korean Peninsula and, although incomplete, is exceptional in its very large size. Characters of the mandible support attribution to crown-group Anguimorpha, with the closest similarities being to monstersaurs, the group represented today by the venomous North American Beaded lizard and Gila monster, genus Heloderma. This group is well-represented in the Upper Cretaceous fossil record in of eastern Asia, and the remains of large monstersaurs have been recovered from several dinosaur egg localities, suggesting dietary preferences similar to those of the living genus. The new Korean lizard, recovered from the Boseong Bibong-ri Dinosaur Egg Site, fits the same pattern. 相似文献
6.
Lida Xing Martin G.Lockley Yongzhong Tang Hendrik Klein W.Scott Persons IV Miaoyan Wang Xingwen Li Hao Wu 《地学前缘(英文版)》2021,12(2):737-745
Poorly preserved tracks have limited ichnotaxonomic or biotaxon utility,but may reveal useful information about the paleoenvironment,behavior and track taphonomy.Eight mostly parallel to sub parallel trackway segments(T1–T8)were registered on a truncation surface in the Lower Cretaceous Luohe Formation of Shaanxi Province.These attest to the passage of several bipeds,probably all theropods,in a paleo-contour-parallel,south-north direction in an arid setting.Quality of preservation in these trackways is poor,but notably superior in two additional trackways(T9–T10)on a foreset surface.Trackway T9 indicates a didactyl trackmaker,probably a deinonychosaurian,heading north to south.This is the 13th report of deinonychosaurian tracks from the Lower Cretaceous of China.If any or all the eight south-north oriented trackway segments represent continuations of other segments in the same trackways,the total number of individual trackmakers heading in this direction may have been as lowas three.Although the trackway pattern and sedimentological evidence could indicate a physically controlled pathway influencing the direction taken by these trackmakers,the possibility that the trackways also represented small social or gregarious group cannot be ruled out. 相似文献
7.
Trackways can provide unique insight to animals locomotion through quantitative analysis of variation in track morphology. Long trackways additionally permit the study of trackmaker foot anatomy, providing more insight on limb kinematics. In this paper we have restudied the extensive tracksite at Barranco de La Canal-1 (Lower Cretaceous, La Rioja, NW Spain) focussing on a 25-m-long dinosaur (ornithopod) trackway that was noted by an earlier study (Casanovas et al., 1995; Pérez-Lorente, 2003) to display an irregular pace pattern. This asymmetric gait has been quantified and photogrammetric models undertaken for each track, thus revealing distinct differences between the right and the left tracks, particularly in the relative position of the lateral digits II–IV with respect to the central digit III. Given that the substrate at this site is homogenous, the consistent repetition of the collected morphological data suggests that differences recorded between the right and the left tracks can be linked to the foot anatomy, but more interestingly, to an injury or pathology on left digit II. We suggest that the abnormal condition registered in digit II impression of the left pes can be linked to the statistically significant limping behaviour of the trackmaker. Furthermore, the abnormal condition registered did not affect the dinosaur's speed. 相似文献
8.
Newly discovered tracks of a large quadrupedal ornithopod and a theropod with trail trace, and a bird track from the Cretaceous Saniri Formation of Yeongdong area are described. One ornithopod trackway is very unusual in having large (length width ∼15 and >15 cm respectively) clover-leaf-like manus tracks situated anteromedial to the pes tracks with atypical negative, inward rotation of 45°. Ornithopod pes tracks are quadripartite with three separated, elongate-oval, nearly parallel sided, wide digit impressions and a separate suboval heel impression (mean length and width about 41 and 36 cm respectively: l/w ratio 1.13). Manus track morphotypes are a clover-leaf-shaped configuration of three digit impressions, representing digits II–IV, in triangular configuration and registered just in front of (anteromedial to) pes track digits II and III. The pes morphotype is typical of Caririchnium, but the manus morphotype is quite distinct from previously described ichnotaxa, thus justifying a new ichnotaxon: Caririchnium yeondongensis ichnosp. nov., probably representing a facultatively-quadrupedal Iguanodon-like trackmaker.Theropod tracks are composed of three tapered pes digit impressions with interdigital angles between digits II and IV 45°. Length and width about 22.8 cm and 15.5 cm, respectively. Pace, stride, and pace angles are about 51 cm, 101 cm, and 170°, respectively. Theropod tracks are characteristically associated with a nearly continuous tail trace, which is up to 360 cm in length, 4.5 to 6 cm in width, and broad “U” shaped in cross section. Expulsion rims and dragging striae occur intermittently. In addition, dinosaur skin impressions, poorly preserved large sauropod tracks, a bird track, invertebrate and plant fossils are found from the lake margin deposits also containing rain drop impressions and desiccation cracks. Dinosaur tracks of the Yeongdong area represent the oldest (Valanginian-Hauterivian) dinosaur tracks of Korea. 相似文献
9.
A sample of fallen blocks of fluvial sandstone from the Lower Cretaceous Jiaguan Formation of Sichuan Province yielded an assemblage of dinosaur and pterosaur tracks preserved as natural impressions and casts. Collectively the assemblage reveals 132 tracks representing at least 30 trackways of tridactyl and didactyl theropods, sauropods, ornithopods and pterosaurs. Ichnotaxonomically, the trackways of small tridactyl theropods (pes lengths 7–18 cm) are indeterminable, whereas the trackway of a small didactyl dromaeosaur (pes length up to 7.5 cm) is tentatively assigned to cf. Velociraptorichnus. The sauropod trackways are assigned to cf. Brontopodus based on the medium to nearly wide-gauge pattern. Other characteristics are the U-shaped manus and strong heteropody. One sauropod trackway shows a peculiar pattern with a lack of left manus imprints, and an unusual position and rotation of right manus imprints. Different scenarios and explanations for this phenomenon are discussed. Ornithopod trackways are the most abundant in the sample and characterized by pes imprints of a small biped that are assigned here to the new ichnospecies Caririchnium liucixini. It is characterized by an unusual broad shape and weak mesaxony. Bivariate analysis of different Caririchnium ichnospecies reveals increasing mesaxony toward the larger forms, a trend that is the reverse of typical theropod ichnotaxa, where large imprints have weak mesaxony. Three isolated, small pterosaur tracks (two manus, one pes) are visible on a single surface. They show strong similarities to the widespread ichnogenus Pteraichnus. This is the ninth report of tetrapod tracks from the Jiaguan Formation in recent years and represents one of the most diverse assemblages recorded to date. It is also rare evidence of typical didactyl dromaeosaur tracks and the co-occurrence of sauropod and ornithopod tracks in a fluvial depositional environment representing arid climate conditions. 相似文献
10.
The Early Cretaceous lizard Yabeinosaurus was one of the first taxa described from the now famous Jehol Biota of northeast China. Misinterpreted for more than 60 years and misclassified as a gekkotan based on juvenile specimens, it is now recognised to be a large, well-ossified lizard with an extended period of skeletal maturation. Here we describe two additional complete specimens of Yabeinosaurus that provide new information on skeletal morphology, most notably of the skull, pectoral girdle, and tail. Both specimens also preserve gut contents, showing that large individuals took vertebrate prey, including fish. A more complete understanding of Yabeinosaurus permits a review of the type specimen of Yabeinosaurus youngi. Skull traits used to distinguish Y. youngi from Yabeinosaurus tenuis are invalid but, as noted by Hoffstetter, the two species differ markedly in limb proportions. Attribution of Young’s specimen to Yabeinosaurus is equivocal, but could potentially extend the temporal range of the lineage into the Jurassic. A new phylogenetic analysis based on a morphological data set places Yabeinosaurus on the stem of Scleroglossa, as the sister taxon of the contemporaneous Japanese lizard Sakurasaurus. 相似文献
11.
Cretaceous dinosaur tracks from Hunan Province are historically significant as the basis for three ichnotaxa: Xiangxipus chenxiensis, Xiangxipus youngi, and Hunanpus jiuquwanensis all representing theropodan tracks, described from a single site in 1982. Although the type locality has since been destroyed, the type specimen and replicas remained available for restudy in 2006, when paratype Hunanpus tracks and sauropod footprints were described from a second, nearby locality. Material from both localities is here re-described in detail. It is proposed that while Xiangxipus chenxiensis can be regarded as a distinct ichnospecies, probably representing an ornithomimid trackmaker, Xiangxipus youngi cannot be accommodated in the same ichnogenus. We consider it similar to the ichnogenus Wupus from the Lower Cretaceous of Sichuan Province, and therefore of possible avian affinity. We also find no justification for regarding Hunanpus jiuquwanensis as generically distinct from the widespread ichnogenus Grallator, and therefore rename it Grallator jiuquwanensis comb. nov. The Hunan track record is generally consistent with the sparse record of theropod skeletal remains in the province, but adds evidence of sauropods that was previously lacking. 相似文献
12.
In recent years the Late Cretaceous (Santonian) terrestrial vertebrate locality at Iharkút (western Hungary) has yielded well-preserved remains of lizard taxa besides the remains of fishes, amphibians, turtles, crocodiles, pterosaurs and dinosaurs. Previously the polyglyphanodontine lizard Bicuspidon aff. hatzegiensis has been reported from Iharkút. However, recent excavations at this site produced more lacertilian remains including new polyglyphanodontine material, namely a maxilla and two dentaries which suggest the presence of a new genus in the Iharkút fauna. This previously unknown lizard (described here as Distortodon rhomboideus n. g. n. sp.) is distinct from other polyglyphanodontines such as Bicuspidon, Paraglyphanodon, Polyglyphanodon, Dicothodon and Peneteius. It differs from these genera mainly in having the lingual cusp situated more distally compared to the labial one on its bicuspid teeth located in the distal part of the tooth row, thus the crowns having a unique rhomboidal shape in occlusal view. Distortodon rhomboideus further strengthens the dominance of borioteiioid lizards in the Iharkút fauna. The growing presence of borioteiioids in European localities supports previous theories which suggest some paleobiogeographic connections between the western Tethyan archipelago and North America in the Late Cretaceous. 相似文献
13.
藏东昌都地区阿涅塘化石点中侏罗世达布卡组滨湖相紫红色中-细砂岩中,发现以凸形迹完好地保存的4层恐龙足迹,包括Grallator类、大型兽脚类、小型兽脚类和小型蜥脚类等足迹类型,并构成两列完美的行迹. 组成行迹T1的4个Grallator类足迹被命名为Grallator anietangensis isp. nov.,对其进行了详细的形态学分析,并讨论了造迹恐龙的大小和运动状态,这是Grallator类足迹在西藏地区的首次发现. 组成行迹T2的9个大型兽脚类足迹被归为Theropoda igen. et isp. indet.,对该类足迹进行了形态描述和功能分析;这类足迹在中国是首次记录,其连续且清晰的尾迹表明造迹者并非处于正常运动状态,而是应对某种特殊境况的特别行为方式,即其正以昂起的前躯一边观察,一边以极低的速度前进,因前躯昂起,尾部相应下垂,从而留下尾迹. 两列行迹均显示出造迹者正沿古昌都湖岸前进. 中国迄今所发现的恐龙骨骼和Grallator类足迹化石主要表现为以西南地区为中心,再向四周不断发散的扩散模式,但Grallator类足迹化石综合提供的信息显示恐龙动物的扩散速度比骨骼化石反映的速度更快. 相似文献
14.
The cymatoceratid nautilid genus Anglonautilus is distinguished from most other post-Triassic nautiloids by the occurrence of pronounced fold-like undulating ribs on the phragmocone and early body chamber. Anglonautilus praeundulatus n. sp. is described from the lower Aptian of eastern Spain. It is the first record of this genus from Spain and constitutes the oldest definite representative of the genus. This places the new species at the base of the evolutionary history of Anglonautilus. Its ornamental features confirm the previously assumed close relationship between Anglonautilus and Cymatoceras. An analysis of the ornamental pattern of all species hitherto referred to Anglonautilus indicates that there is an evolutionary lineage leading to the type species of the genus, A. undulatus, and a single successor (A. subalbensis). Several Late Cretaceous species hitherto identified as Anglonautilus (A. japonicus, A. mamiyai, A. suciensis) bear fold-like ribs superficially similar to typical representatives of Anglonautilus. The pattern of ornament in these taxa is very different at closer inspection, though. This suggests that these species developed independently from Cymatoceras. The undulations present in these taxa are interpreted here as a result of convergent evolution. They are therefore excluded from the genus Anglonautilus and provisionally referred to as “Anglonautilus” spp. 相似文献
15.
Cretaceous strata in Alabama and Mississippi (USA) represent one of the most complete records of shallow marine deposition worldwide for the Upper Cretaceous. The age assignment of these strata in the eastern Gulf Coastal Plain is difficult due to the comparative lack of radiometrically datable beds and sometimes conflicting results of biostratigraphy using different taxonomic groups. Numerical age dating using strontium isotope ratios (87Sr/86Sr) preserved in diagenetically resistant fossil shark tooth enameloid had been proposed by previous researchers as a solution to dating some geologic units. Here we apply this methodology to the whole Upper Cretaceous, using teeth of two fossil shark genera (Scapanorhynchus and Squalicorax) collected from variable facies. Shark teeth collected from a bentonite mine in Monroe County, Mississippi, were also analyzed and compared with the radiometric date of the bentonite layer. Results indicate a strong correlation between stratigraphic position of the fossil teeth and numerical age determination based on 87Sr/86Sr content. Furthermore, this method is equally effective for both of the fossil shark genera analyzed in the study. Because of the nearly uniform distribution of strontium in ocean water, numerical age dating using strontium isotope ratios preserved in fossil shark tooth enameloid can be a useful method to employ in the correlation of marine geological strata on both regional and global scales. 相似文献
16.
17.
Yabeinosaurus was the first lizard genus described from the Early Cretaceous Jehol Biota of China. The holotype of the type species, Y. tenuis, is an immature skeleton but it has been lost for decades. A second species, Y. youngi, was erected based on another immature skeleton and is distinguished by its longer, more gracile limbs. In 2001, a juvenile skeleton from the Jingangshan locality of Liaoning was designated as the neotype for Y. tenuis. Subsequently, several further specimens from other localities, juvenile and adult, have been attributed to this species. Here we describe a second lizard specimen from the neotype locality. In anterior tooth shape, finger-like mandibular angular process, cranial sculpture, maxilla shape, and short, robust humerus, the new specimen resembles adult and subadult material currently attributed to Y. tenuis, but it differs in having bicuspid posterior teeth and a straight rather than a hooked angular process of the mandible. We propose a new species (Y. bicuspidens sp. nov.) for this specimen which represents the first occurrence of bicuspid teeth in an Early Cretaceous lizard from China. However, the recognition of a second species at the neotype locality raises a taxonomic problem. Due to the immaturity of the designated holotype and neotype of Y. tenuis, they cannot be coded for the jaw and dental characters that distinguish the two robust-limbed species. This renders Yabeinosaurus tenuis a nomen dubium. Here we propose that Yabeinosaurus tenuis should be treated as a historic taxon, permitting retention of the generic name under ICZN rules, and erect a second new species (Y. robustus sp. nov.) for the principal robust-limbed morphotype in the Jehol Biota with monocuspid posterior teeth and a hooked angular process. 相似文献
18.
The stratigraphic division and sequence of the Upper Cretaceous sediments in eastern Heilongjiang Province,China,have been ambiguous and controversial,mainly due to a lack of biostratigraphically useful fossils and related radiometric dating.A new species of angiospermous fossil plant.Platanus heilongjiangensis sp.nov.,from Qitaihe in eastern Heilongjiang has been found in sediments conformably above which zircons from a rhyolitic tuff has been dated by U-Pb radiometric methods as 96.2± 1.7 Ma.indicating that the Upper Houshigou Formation is of Cenomanian age.This discovery not only provides new data to improve our stratigraphic understanding of the Houshigou Formation,but also shows that Platanus flourished in the early Late Cretaceous floras of the region.This new study also indicates active volcanism taking place in the eastern Heilongjiang region during the Cenomanian of the Late Cretaceous. 相似文献
19.
江苏省新沂市马陵山地区的4个神秘的印记,传统上被解释为“李存孝打虎处”的“虎爪印”和“人足迹”,重新将其解释为大盛群田家楼组恐龙足迹。这些足迹中只有一个最深的“虎爪印”保存了可识别的趾印,表明它是一个有着后内侧拇趾印的兽脚类恐龙左足迹,是一道单步约50cm的直线行迹的一部分;另一种解释是该足迹为小型蜥脚类恐龙的右后足迹,形成行迹的右侧部分,其左侧部分没有保存。马陵山足迹点提供了恐龙足迹如何影响中国民间传说的另一个案例。 相似文献
20.
Two pes imprints of a perissodactyl mammal constituting a single step of a trackway have recently been discovered in Oligocene Flysch deposits of the Barail Group in Manipur, India. The tridactyl, mesaxonic imprints (~7 cm in length) show strong similarities to footprints known from the Paleogene of China and can be attributed to a tapiroid, rhinocerotoid or equoid trackmaker. This is the first record of perissodactyl footprints from the Lower Oligocene of India and the first evidence of mammals in the Barail Group of the age. Remarkable is the occurrence in a marginal marine setting, whereas other known perissodactyl footprints from the Eocene–Oligocene in particular from North America, Europe and China come from fluvio-lacustrine strata. 相似文献