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1.
A previously unknown and morphologically distinct pentadactyl mammal track was recovered from the Upper Cretaceous (Maastrichtian) Laramie Formation at the Fossil Trace site, a National Natural Landmark which is the type locality for Schadipes crypticus, the only named mammal track known from North America. The track is different, and larger than S. crypticus, and thus is evidence of a diversity of mammal trackmakers at this site. Although Cretaceous mammal tracks are very rare, preliminary indications are that those currently known are all morphologically distinct and therefore indicative of a global diversity of different trackmakers, as the body fossil record suggests. Lack of well-preserved mammal trackways with morphologically distinct manus and pes footprints hampers efforts to name diagnostic ichnotaxa. 相似文献
2.
基于恐龙足迹重建攀西地区白垩纪恐龙动物群 总被引：2，自引：2，他引：0
攀西地区没有白垩纪恐龙骨骼化石记录,对该区白垩纪恐龙动物群组合的认识尚属空白。1991年,攀西地区首次发现了恐龙足迹,此后陆续发现了8个足迹点。这些足迹点共发现9种不同的非鸟恐龙足迹(6种非鸟兽脚类、1种蜥脚类和2种鸟脚类足迹),以及翼龙和龟类足迹。共11种足迹形态类型由185道行迹(与孤立足迹)组成,可能代表着同等数量的造迹者。其中飞天山组的组合多样性最强,小坝组和雷打树组较弱。这个相对全面的足迹数据库,为该地区白垩纪四足类的古生态学普查提供了动物群的组成信息,这在该缺乏骨骼化石的地区显得尤为重要。 相似文献
3.
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
4.
1923年Nopcsa命名的Emydichnium是龟类足迹最早的报道,后来其他一些中生代的足迹也被陆续报道描述。但是大多数化石只显示出或多或少的明显爪印或者划痕,无法反映造迹者足部较为全面的生物学特征。山东诸城皇龙沟足迹点保存了早白垩世大量形态多样的龟类足迹,本文对其中一保存较好,能够反映足部生物学特征的龟类足迹进行了详细描述,并依据数据统计与莱阳足迹Liayangpus进行对比,显示两者存在明显不同。诸城的龟类足迹区别于以往发现的龟类足迹,因此根据其形态建立新种：完整诸城足迹Zhuchengichnites perfectus。本文亦对中国发现的龟类足迹化石点的层位、保存类型等进行了总结。 相似文献
5.
1923年Nopcsa命名的Emydichnium是龟类足迹最早的报道,后来其他一些中生代的足迹也被陆续报道描述。但是大多数化石只显示出或多或少的明显爪印或者划痕,无法反映造迹者足部较为全面的生物学特征。山东诸城皇龙沟足迹点保存了早白垩世大量形态多样的龟类足迹,本文对其中一保存较好,能够反映足部生物学特征的龟类足迹进行了详细描述,并依据数据统计与莱阳足迹Liayangpus进行对比,显示两者存在明显不同。诸城的龟类足迹区别于以往发现的龟类足迹,因此根据其形态建立新种：完整诸城足迹Zhuchengichnites perfectus。本文亦对中国发现的龟类足迹化石点的层位、保存类型等进行了总结。 相似文献
6.
主要记述了山东临沭地区早白垩世晚期(大盛群沉积时期）、生活于干旱炎热气候条件下滨浅湖环境的恐龙所留下的大规模足迹化石群。初步研究表明,这些足迹以蜥脚类恐龙足迹占绝大多数,见少量鸟脚类、兽脚类和疑似甲龙类足迹(甲龙类足迹在中国罕见),足迹总体行进方向以向西和南西为主。通过对其中的2条蜥脚类和1条鸟脚类行迹及其行为学的分析认为其均处于慢行状态,而鸟脚类行迹的运动速度极慢,可能处于一种特殊的慢行状态。临沭地区早白垩世晚期大盛期如此大规模足迹化石群的发现,说明中国乃至东亚地区早白垩世普遍存在着以恐龙为代表的(包括鸟类在内）陆生脊椎动物群。足迹化石的研究将对进一步了解晚中生代陆地生物群的演化有着重要意义。对比其他地区早白垩世晚期地层中发现的恐龙足迹化石特征后认为,足迹的保存与当时的沉积环境有密切的关系,因此对恐龙足迹的研究又能进一步为恢复古生态、古地理环境等提供更丰富的信息。 相似文献
7.
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
8.
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
9.
Cajus G. Diedrich 《Central European Journal of Geosciences》2012,4(3):495-529
Chirotherid footprints of Synaptichnium, Chirotherium and Isochirotherium appeared during the late Early (Aegean) to early Late (Carnian) Triassic in central Europe. These taxa are partly revised herein, using both perfect and variably preserved tracks, and very long trackways from an upper Pelsonian intertidal-flat megatracksite of the Germanic Basin coast Pelsonian (Karlstadt Formation). The global Middle Triassic distribution of those footprints suggests seasonal migrations across Pangaea of possible archosauriform reptile trackmakers, such as Euparkeria, Ticinosuchus, Arizonasaurus and Batrachotomus, caused by horseshoe-crab mass migrations into tidal-flat beach reproductive zones in the Germanic Basin. Such seasonal migrations may even suggest a Pangaea-wide food-chain reaction, possibly including the mobilization of fish, marine and terrestrial reptiles, and of which situation the Germanic Basin intertidal-flats is a globally unique example. 相似文献
10.
J.G. Hudson 《Geology Today》2009,25(3):108-111
In December of 2004 a dinosaur footprint was discovered near Scarborough on the North Yorkshire coast of northern England. Arguably, it was the largest and best-preserved theropod print yet discovered on this coast, and indicated for the first time that large carnivores were present in the area around 165 million years ago. Many trace fossils are enigmatic ghosts of the animal that formed them, but footprints are so much more tangible; a footprint preserved from Jurassic time represents an individual animal, walking in this place at this time. In this article I provide the background to the discovery and collection of this trace fossil, which has enabled this footprint in time to be preserved for future study. 相似文献
11.
12.
A new Lower Cretaceous (lower Aptian) dinosaur tracksite, from the eastern side of Monte Cagno (Abruzzi, Italy), is described. Different styles of track formation are represented on the site surface. Most of the footprints are preserved as deep tracks, produced by trackmakers sinking into soft mud. Some tracks, better preserved than the others, are characterized by metatarsal impressions and were interpreted as the resting traces of a crouching theropod (based on their orientation and three-dimensional morphology). The 135 cm length of the track with metatarsal impressions indicates huge pedal proportions and represents the largest theropod trackmaker ever documented from the Mesozoic peri-Adriatic platforms of Italy. 相似文献
13.
14.
Two ichnogenus of “large-sized” ornithopods are found from the Lower Cretaceous (Aptian) Kitadani Formation in central Japan. Caririchnium isp. is characterized by the longer pes print than its width with strong mesaxony. Amblydactylus isp. is characterized by the wider pes print than its length with weak mesaxony. In the northern hemisphere, Caririchnium-type footprints are known from the Berriasian–Cenomanian strata, whereas Amblydactylus-type footprints are known from the Barremian–Maastrichtian strata. It is consistent with the temporal and geographic distribution of non-hadrosauroid iguanodontians and basal hadrosauroids. It suggests that footprint length-width ratio and mesaxony are important factors to indicate trackmakers (basal iguanodontian or hadrosauroid). Two “large-sized” ornithopod ichnogenus from the Kitadani Formation is also consistent with two iguanodontians from same site. It indicates a high diversity of the Kitadani ichnofauna and its importance to elucidate the ecosystem of the Kitadani Formation. 相似文献
15.
Jyoti Shah Deepak C. Srivastava Vipul Rastogi Rajit Ghosh Aditi Pal 《Journal of the Geological Society of India》2010,75(1):89-97
Most of the existing methods of strain analysis can estimate strain in a single form of distorted brachiopod, or trilobite
provided independent evidence, such as the association of the fossil with cleavage and/or stretching lineation is available
for inferring the direction of maximum principal strain. This article proposes a simple computer graphics based method and
its MATLAB code that determine the minimum amount of strain in a single distorted fossil form even if data for inferring the
maximum principal strain direction are lacking. Our method is a rapid computer-graphics alternative to some of the existing
analytical methods.
In a distorted fossil form of original bilateral symmetry, the relative senses of angular shears along the hinge line and
the median line are mutually opposite to each other. It follows, therefore, that the maximum principal strain direction lies
within the acute angle between the hinge and the median lines in the plane of the fossil. Using this principle, our method
performs several simulations such that each simulation retrodeforms the distorted fossil by assuming a particular orientation,
lying within the acute angle between the hinge line and the median line, as the potential direction of the maximum principal
strain. Each simulation of retrodeformation yields a potential strain ratio. The distribution of all the potential strain
ratios, obtained by assuming different orientations as the potential directions of the maximum strain, is typically a parabola-like
curve with a distinct vertex that corresponds to the minimum amount of strain in the distorted fossil. An entirely computer
graphical approach is somewhat time-intensive because it involves a large number of retrodeformational simulations. We, therefore,
give a MATLAB code, namely, the Minstrain, that rapidly retrodeforms the fossil and determines the minimum strain with precision. 相似文献
16.
Aleksandar Mezga Christian A. Meyer Blanka Cvetko Te&#x;ovi&#x; Zlatan Bajraktarevi&#x; Ivan Gu&#x;i&#x; 《Cretaceous Research》2006,27(6):735-742
The first discovery of dinosaur footprints on the Dalmatian part of the Adriatic-Dinaric carbonate platform (ADCP) is reported. They constitute the geologically youngest record of footprints on the ADCP. The trackbearing layer was formed in the intertidal environment and represents the final stage of a shallowing-upward cycle. Just below it, a heavy dinoturbated limestone layer can be observed. Microfacies analysis, incorporating evidence from benthic foraminifera and algae, indicates a Late Turonian–Early Coniacian age. The overall morphology and size of the footprints points to sauropod dinosaurs; they represent the largest forms recorded so far on the ADCP. This hints at a prolonged sauropod presence on the platform and to its Late Cretaceous connection to the continent rather than isolation. 相似文献
17.
The Wapiti Formation in west-central Alberta preserves one of the most diverse Late Cretaceous terrestrial track records yet identified in Canada. At least seven morphotypes are recognized and attributed to mammals, small reptiles or amphibians, tyrannosaurids, medium-sized theropods, hadrosaurids, and ankylosaurs. Most tracks occur isolated on slump blocks associated with latest Campanian (Wapiti Formation unit 4) exposures found along Pipestone Creek and Red Willow River. With the possible exception of hadrosaurids, tracks provide some of the most compelling evidence for the occurrence of such taxa within the Wapiti Formation ecosystem. The apparent absence of ceratopsian tracks is surprising considering their bones are abundantly preserved in nearby monodominant bonebeds. The overall faunal signal represented by the Wapiti Formation trackmakers is typical of and consistent with other coeval assemblages in similar environments. The Wapiti Formation tracks, combined with the known fossil bone record, provide another data point in a growing palaeobiogeographical picture of the dinosaur faunas of high-latitude northwestern North America during the Late Cretaceous. 相似文献
18.
自20世纪50年代发现长阳人化石以来,迄今在鄂西-三峡地区已经发现了至少10处古人类化石地点,时代跨越了整个更新世时期,尤其以更新世中、晚期人类化石最为丰富。除人类化石外,在这一地区还发现了大量的古人类制作的石器、骨器、艺术品、装饰品等人类活动遗存,以及与古人类伴生的动物化石。近年的野外发掘及实验室研究证明鄂西-三峡地区更新世中期以来一直是古人类生存与繁衍昌盛的区域,该地区丰富的古人类资源对研究与中国古人类演化有关的一系列关键学术问题具有非常重要的价值。 相似文献
19.
Here we describe a new record of a sauropod dinosaur from the Lower Cretaceous (Hauterivian–Barremian) Rio Piranhas Formation, Sousa Basin, NE Brazil. Dinosaur fossil bones from this deposit were unknown until now. Thus, the discovery of a sauropod fibula from this locality is highly significant. Our discovery represents an indeterminate titanosaur and the earliest stratigraphic occurrence of this group in central Gondwana. When compared to chronocorrelate titanosaur trackmakers of this geological unit, this fossil specimen appears substantially smaller. Histological analysis of the fibula suggests that this is a relatively young individual (approximately 40–50% adult body size) that had passed its most rapid phase of early juvenile growth, but had not yet attained somatic maturity. Thus, the fibula recovered is from a young individual rather than from a small-bodied adult titanosaur. 相似文献
20.
本文记述了发现于宁夏六盘山地区的恐龙足迹化石。共计5个化石点,分别位于宁夏六盘山地区固原市隆德县和泾源县,赋存地层为下白垩统六盘山群和尚铺组、李洼峡组和马东山组,包括蜥脚类和鸟脚类恐龙足迹化石,其中以蜥脚类为主。足迹可识别的有4条行迹,其中,隆德县香水镇行迹所代表的恐龙个体较小,臀高仅1.44m,其余3组行迹代表的恐龙较大,臀高在2.79～3.27m之间;鸟脚类恐龙臀高约为0.48 m,为小型鸟脚类恐龙。采用Alexander的速度计算方法对造迹恐龙的速度进行研究,表明六盘山地区蜥脚类造迹恐龙速度为0.34～1.41m/s之间,复步长与臀高的比值小于2,均为正常行走状态。足迹保存层面岩性主要为粉砂质泥岩、细砂岩,具水平层理、波痕、泥裂、雨雹痕等沉积构造,含植物碎片化石,并发育有大量的无脊椎动物潜穴化石。根据岩性及沉积构造判断,造迹恐龙活动环境为离湖岸较近的浅水地带。 相似文献