Sauropod and Small Theropod Tracks from the Lower Jurassic Ziliujing Formation of Zigong City,Sichuan, China,with an Overview of Triassic–Jurassic Dinosaur Fossils and Footprints of the Sichuan Basin

A dinosaur footprint assemblage from the Lower Jurassic Ziliujing Formation of Zigong City, Sichuan, China, comprises about 300 tracks of small tridactyl theropods and large sauropods preserved as concave epireliefs (natural molds). The theropod footprints show similarities with both the ichnogenera Grallator and Jialingpus. Three different morphotypes are present, probably related to different substrate conditions and extramorphological variation. A peculiar preservational feature in a morphotype that reflects a gracile trackmaker with extremely slender digits, is the presence of a convex epirelief that occurs at the bottom of the concave digit impressions. It is possibly the result of sediment compaction underweight load when the pes penetrated the substrate, being a resistant residue during exhumation and weathering. The sauropod tracks belong to a trackway with eight imprints consisting of poorly preserved pes and manus tracks and a better preserved set, probably all undertracks. The narrow-gauge trackway pattern resembles the ichnogenus Parabrontopodus well known from the Jurassic but other features such as the minor heteropody are different. The assemblage enriches the dinosaur record from the famous Zigong locality and the evidence from the Lower Jurassic in this area that was restricted to a few skeletal remains and footprints. Furthermore it proves the presence of small theropods, whereas skeletons of the group, well- known from the Middle-Upper Jurassic of Zigong, are of medium to large size only. Remarkable is the dominance of saurischians in these assemblages, which is characteristic of Jurassic dinosaur communities whereas the Cretaceous record shows an increase of ornithopod groups. An overview of the dinosaur trace and body fossil record of the Sichuan Basin supports this view. The paleoenvironment can be designated as a low-latitude tropical freshwater lake as it is indicated by bivalve shells.     

Dinoturbation in Upper Jurassic siliciclastic levels at Cabo Mondego (Lusitanian Basin,Portugal): evidences in a fluvial-dominated deltaic succession

At Cabo Mondego (western central Portugal), the Upper Jurassic marine to coastal succession contains several stratigraphic levels preserving dinosaur footprints on the surface bedding plane, as well as convolute bedding and soft sediment injection structures interpreted as dinoturbation structures. At least nineteen new three-dimensional structures observed in cross-sections are interpreted as produced by dinosaur trampling. The identification of three-dimensional structures of dinosaur footprints provides an important complement to the information obtained from footprints preserved on single bedding surfaces, such as the substrate consistency, potential trackmaker identification, and the possibility to enhance the distinction of sauropods and tridactyl dinosaurs, and paleoenvironmental interpretations. In the lower part of the Arenitos da Boa Viagem Formation, eight levels of probable lowermost Kimmeridgian age (ca. 157–156 Ma), displaying the above-mentioned deformational structures, were analyzed in detail. They support interpretations concerning the relationship between the footprints and the substrate consistency at the time of their formation. Three distinct cohesiveness patterns, defined by the penetration of the feet from the paleosurface, are the result of different degrees of substrate cohesiveness. Identifying the trackmakers of levels belonging to the middle Oxfordian–lower Kimmeridgian has important implications for Late Jurassic ecosystem reconstructions, as the footprints observed in Cabo Mondego indicate a change in the morphotypes throughout the Upper Jurassic succession.     

New dinosaur tracksites from the Middle Jurassic of Madagascar: ichnotaxonomical,behavioural and palaeoenvironmental implications

Abstract: New dinosaur tracksites are described from the Bajocian–Bathonian Bemaraha Formation of western Madagascar. Two track‐bearing surfaces can be followed over a distance of at least 4 km, suggesting the existence of a hitherto unrecognized megatracksite. The track assemblage is theropod dominated, but sauropod tracks also occur at one site. Qualitative and quantitative analysis of the abundant theropod track material suggests that most, if not all, theropod footprints are attributable to a single trackmaker and are referred to Kayentapus isp. Although this ichnogenus, originally described from the Lower Jurassic of North America, has never been recorded from Gondwana nor from the Middle Jurassic, track morphology strongly suggests this attribution. Palaeogeographical, sedimentological and ichnological data suggest that the dinosaur tracks formed in an intertidal to supratidal setting where the coastline influenced the preferred walking direction of the animals.     

Unusual deinonychosaurian track morphology (Velociraptorichnus zhangi n. ichnosp.) from the Lower Cretaceous Xiaoba Formation,Sichuan Province,China

A new Lower Cretaceous dinosaur footprint locality named the Mujiaowu tracksite in the Xiaoba Formation, Sichuan Province, has yielded a new assemblage containing the didactyl deinonychosaurian ichnogenus Velociraptorichnus. This is the eleventh report in the global record, the seventh from Asia and the fifth from China. All, except for an isolated report from Europe, occur in Lower Cretaceous deposits. Unlike previous reports of the ichnogenus, the Mujiaowu site has yielded both didactyl Velociraptorichnus tracks and tridactyl tracks which we interpret as a different expression of this same ichnogenus, caused by registration of digit II, either due to special substrate conditions or to less claw retraction. These tridactyl Velociraptorichnus footprints are assigned to the new ichnospecies Velociraptorichnus zhangi. Such tridactyl deinonychosaurid footprint morphology is predictable, but based on current ichnological evidence appears to be the exception rather than the rule.     

Theropod and possible ornithopod track assemblages from the Jurassic–Cretaceous boundary Houcheng Formation,Shangyi, northern Hebei,China

Dinosaur track assemblages from the Houcheng Formation in the small continental Shangyi Basin of northern Hebei Province, China bridge a gap in the record of vertebrates from this unit and enrich our knowledge of ichnofaunas from the Jurassic–Cretaceous boundary. Their stratigraphic position between the Middle Jurassic Yan-Liao Biota and the Lower Cretaceous Jehol Biota gives them a special importance. New discoveries allow a re-assessment of theropod and possible ornithopod tracks that are present with several trackways. Seventy-three footprints were examined and documented. Despite their smaller size, the tridactyl mesaxonic theropod tracks show morphological similarities with the ichnogenus Therangospodus known from the Upper Jurassic deposits of North America, Europe, and Central Asia. The possible ornithopod tracks lack an associated manus imprint, suggesting a bipedal trackmaker. These possible ornithopod tracks from the Houcheng Formation provide evidence for the presence of small basal ornithopods or basal Cerapoda in the Upper Jurassic–Lower Cretaceous in this region. The depositional environment was the margin of an extensive shallow lake with fluctuating water levels under seasonally dry climate.     

Hoof-Like Unguals,Skin, and Foot Movements Deduced from Deltapodus Casts of the Galve Basin (Upper Jurassic-Lower Cretaceous,Teruel, Spain)

Galve (Teruel, Spain) is a town in the interior of a synclinal fold with Upper Jurassic marine limestones along its flanks, and, in its core, Upper Jurassic–Lower Cretaceous continental and shoreline sediments crop out. The core sediments cover an area about 8 km², and contain a concentration of sites with footprints, bones, and eggshells of dinosaurs. The footprints are both shafts and natural casts. Some casts are attributed to stegosaurs (Deltapodus). The Deltapodus casts are characterized by features that allow us to make direct observations on the skin formed by polygonal scales, and ellipsoidal “hooves,” as well as deductions on the movement of the limbs during walking. According to the opinion of some authors, dinosaur footprints are indicators of the motion of their limbs and sometimes of the whole body. So far, results have been deduced from theropod, ornithopod, and sauropod footprints. This article shows the results obtained from analis of the aforementioned Deltapodus casts, i.e., forelimb movement similar to that of the forelimbs of sauropods, and the rigid structure of the autopodial part of the hind limb.     

A new sauropodomorph ichnogenus from the Lower Jurassic of Sichuan,China fills a gap in the track record

A dinosaur tracksite in the Lower Jurassic Ziliujing Formation of Sichuan Province, China consists of a spectacular sub-vertical exposure, with multiple track-bearing levels and trackways showing parallel and bimodal orientations. Based on well-preserved material, the new ichnogenus and ichnospecies, Liujianpus shunan ichnogen. nov. ichnosp. nov. is erected to accommodate distinctive sauropodomorph trackways occurring in this assemblage. Liujianpus has a unique combination of features, some relating to the early Jurassic basal sauropodomorph (prosauropod in traditional usage) ichnogenus Otozoum, others to the sauropod ichnogenus Brontopodus. Despite such a mix of basal sauropodomorph- and sauropod-like features, the trackmaker of Liujianpus is likely a basal sauropodomorph. This identification is consistent with the occurrence of basal sauropodomorph skeletons from geographically and chronologically close localities. The other distinct morphotype from the tracksite is linked to a sauropod trackmaker. As such, the ichnofauna consisting of two distinct foot morphotypes reflects the diversity of sauropodomorph dinosaurs in the Early Jurassic of Asia.     

The History of Dinosaur Footprint Discoveries in Wyoming with Emphasis on the Bighorn Basin

Dinosaur traces are well known from the western United States in the Colorado Plateau region (Utah, Colorado, New Mexico, and Arizona). Utah contains the greatest abundance of known and documented dinosaur footprints and trackways. Far less well known, however, is the occurrence and distribution of dinosaur footprint-bearing horizons in Wyoming. Scientific studies over the past 10 years have shown that three of the four Middle and Upper Jurassic formations in northern Wyoming contain dinosaur footprints. Two of the footprint-bearing horizons are located in geologic intervals that were once thought to have been deposited in offshore to nearshore marine settings and represent rare North American examples of Middle Jurassic (Bajocian and Bathonian) dinosaur remains. Some of these new Wyoming sites can be correlated to known dinosaur footprint-bearing horizons or intervals in Utah. Wyoming has a great potential for additional discoveries of new dinosaur footprint-bearing horizons, and further prospecting and study is warranted and will ultimately lead to a much better understanding of the geographic distribution and behavior of the potential footprint-makers.     

Vertebrate Tracksites in the Middle Jurassic-Upper Cretaceous of South Tunisia

Four vertebrate tracksites from the Middle Jurassic and Upper Cretaceous in the Tataouine basin of southern Tunisia are described. Approximately 130 tridactyl footprints distributed over an area of 200 square meters, preserved on Callovian beds exposed at the Beni Ghedir site, represent the oldest evidence of a dinosaur fauna in Tunisia. In addition, three tracksites—Chenini, Ksar Ayaat, and Jebel Boulouha—have been discovered in the Cretaceous beds of the upper Continental Intercalaire, previously considered as a strictly marine depositional sequence. In addition to dinosaur tracks, the Chenini tracksite (late Albian) includes poorly preserved crocodilian tracks, and footprints assigned to a pleurodiran turtle have been recovered at the Ksar Ayaat locality (early Cenomanian). The Jebel Boulouha tracksite is dominated by well-preserved tridactyl tracks referred to small-sized theropods. Depositional settings of each tracksite have been defined on stratigraphic and sedimentologic data, and tracks were ascribed to different ichnocoenoses in relation to their paleoenvironments. This new and differentiated track record gives important information on how the fossil vertebrate fauna changed in southern Tunisia during mid-Jurassic to mid-Cretaceous times. These data provide a unique and useful census of tetrapod associations along the southern margin of the peri-Mediterranean area.     

The non-avian theropod track Jialingpus from the Cretaceous of the Ordos Basin,China, with a revision of the type material: Implications for ichnotaxonomy and trackmaker morphology

Deposits from the Ordos Basin of mid-western China are rich in body fossils and ichnofossils of Early Cretaceous vertebrates. Thousands of Early Cretaceous sauropod, theropod and bird tracks described since 1958 have been found at several localities in the basin. We report two new sites (Dijiaping and Bawangzhuang) in the Luohe Formation of the Ordos Basin, Shaanxi Province, which contain small theropod footprints that are here referred to the ichnogenus Jialingpus. The assignment is based on pad configurations including (1) the large metatarsophalangeal area positioned in line with the axis of digit III, (2) the subdivision of this part into a small pad behind digit II, which in some specimens is close to the general position of the hallux (digit I), and a large metatarsophalangeal pad behind digit IV, and (3) a distinct inter-pad space between metatarsophalangeal pads and proximal phalangeal pads of digits II and III. We re-describe the type material of the type ichnospecies Jialingpus yuechiensis from the Upper Jurassic Penglaizhen Formation of Sichuan Province, proposing a largely amended diagnosis for this ichnotaxon. The presence of a digit I trace in the holotype, indicating a relatively long hallux, and the large metatarsophalangeal area positioned in line with digit III distinguishes Jialingpus from the ichnogenus Grallator and similar tracks that all lack these features. The only difference between Jialingpus specimens from the Cretaceous of the Ordos Basin and those of the Jurassic Penglaizhen Formation is the larger digit divarication in the Cretaceous taxon. This is the fourth record of Jialingpus in China and the second in Cretaceous strata, with the first being those from the Huangyangquan locality in Xinjiang, China.     

Review of Japanese Dinosaur Track Localities: Implications for Ichnotaxonomy,Paleogeography and Stratigraphic Correlation

Nine dinosaur ichnospecies from the Lower Jurassic to Upper Cretaceous of Japan, including two that are new, are described herein. The new ichnotaxa are Asianopodus pulvinicalx ichnogen. et ichnosp. nov. and Schizograllator otariensis ichnosp. nov. The Japanese ichnotaxa are allied to Lower Jurassic ichnospecies in South China, North America, Western Europe and South Africa, and Upper Jurassic to Lower Cretaceous ichnospecies from Southeast and East Asia. This suggests they were part of a global ichnofauna before continental drift began in the Middle Jurassic, leading to the development of a more endemic dinosaur fauna in the Cretaceous. At least two assemblages, an ornithopod-gracile-toed theropod-dominated community, in northeastern Asia, and a robust theropod- and sauropod-dominated community in the southern part of the continent, existed in the Cretaceous. This parallels North American dinosaur distribution patterns in the Cretaceous and seems to be a reflection of paleolatitudinal controls.     

A diverse Upper Jurassic dinosaur ichnofauna from central‐west Portugal

Mateus, O. & Milàn, J. 2009: A diverse Upper Jurassic dinosaur ichnofauna from central‐west Portugal. Lethaia, Vol. 43, pp. 245–257. A newly discovered dinosaur track‐assemblage from the Upper Jurassic Lourinhã Formation (Lusitanian Basin, central‐west Portugal), comprises medium‐ to large‐sized sauropod tracks with well‐preserved impressions of soft tissue anatomy, stegosaur tracks and tracks from medium‐ to large‐sized theropods. The 400‐m‐thick Lourinhã Formation consists of mostly aluvial sediments, deposited during the early rifting of the Atlantic Ocean in the Kimmeridgian and Tithonian. The stratigraphic succession shows several shifts between flood‐plain mud and fluvial sands that favour preservation and fossilization of tracks. The studied track‐assemblage is found preserved as natural casts on the underside of a thin bivalve‐rich carbonate bed near the Tithonian–Kimmeridgian boundary. The diversity of the tracks from the new track assemblage is compared with similar faunas from the Upper Jurassic of Asturias, Spain and the Middle Jurassic Yorkshire Coast of England. The Portuguese record of Upper Jurassic dinosaur body fossils show close similarity to the track fauna from the Lourinhã Formation. □Dinosaur tracks, Lusitanian Basin, Portugal, skin impressions, Upper Jurassic.     

重庆晚侏罗世两处兽脚类足迹组合与四川盆地侏罗纪地层(英文)

重庆市已报道了4处侏罗纪的恐龙足迹点,包括下侏罗统珍珠冲组的大足化石点,该地点发现了中国迄今最古老的蜥脚类行迹;另外两处化石点(南岸和金鸡)的层位曾被视为中或上侏罗统,这里首次将其确认为上侏罗统上沙溪庙组;第4处化石点(成渝), 本文全部作者目前都未曾观察,这里不做描述。南岸化石点是南岸重庆足迹(Chongqingpus nananensis)模式标本的所在地,位于重庆市中心,曾发现过大量兽脚类足迹,如今已消逝在城市化进程中。幸运的是,这批标本被保存于重庆自然博物馆,本文作者曾前后两次对其进行研究,并得出文中的结论。南岸重庆足迹为中型足迹(平均长约29 cm), 最可能被卡岩塔足迹(Kayentapus)所囊括,这批标本中有一些保存着边界不清的拇趾迹。该化石点的其他足迹被归于似异样龙足迹(cf. Anomoepus)。其他较小的、来自重庆市周边中侏罗统中部的足迹此前已被归于跷脚龙足迹(Grallator)。金鸡化石点保存了一条孤立的兽脚类行迹,因其粗壮的特征而被暂时归于似窄足龙足迹(cf. Therangospodus)。金鸡点的行迹也保存了非连续出现的拇趾迹。虽然重庆市和四川盆地及其周边更广泛地区之侏罗纪地层发现的兽脚类足迹日渐增多,但要明确其确切地质年龄及有效的足迹分类依然需要进一步工作。这是因为侏罗纪的恐龙足迹尽管丰富,但显示出连续变化的形态学特征,而保存状况的变化更使其难以在时间与空间上做出定义与鉴别。     

First Thyreophoran Type Tracks from the Middle Jurassic Chuanjie Formation of Yunnan Province,China

Two tridactyl footprints from the Chuanjie Formation (Middle Jurassic) of Yunnan Province, China are morphological characteristics of thyreophoran tracks. They show some similarities to Shenmuichnus, known from the Early Jurassic strata of both Shaanxi and Yunnan provinces, but are somewhat larger, thereby resembling the ichnogenus Stegopodus. Based on their general morphology and size being congruent with this ichnogenus, they are tentatively assigned here to cf. Stegopodus. This is the fourth report of large ornithischian (probably thyreophoran) tracks from the Lower-Middle Jurassic of China that indicates relatively large trackmakers that were likely to be taxonomically distinct from much smaller and gracile Anomoepus trackmakers, also of ornithischian affinity. The larger tracks indicate a hitherto unreported abundance, size range and diversity of track types attributed to this group. The parallel orientation of the two best preserved trackways may indicate gregariousness.     

An enigmatic early mesozoic dinosaur trackway from Zimbabwe

A trackway from Zimbabwe of probably the smallest dinosaur footprints recorded in Africa, is described and tentatively assigned to the Early Jurassic. The footprints are possibly those of a theropod and show strong negative (outward) rotation of the pes and are associated with manus prints. The shape of the footprints, unusual negative rotation, posterior curvature of digit IV and curious positioning of the manus prints in relation to the pes are enigmatic but somewhat reminiscent of Atreipus. Although a number of propositions are considered the most likely is that the animal was an immature dinosaur using a quadrupedal gait. A second trackway of slightly larger footprints of a bipedal theropod dinosaur is also recorded along with other diminutive tracks that suggest an early dinosaur assemblage, possibly dating from near the Trias‐sic‐Jurassic boundary.     

A Diverse Dinosaur-Bird Footprint Assemblage from the Lance Formation,Upper Cretaceous,Eastern Wyoming: Implications for Ichnotaxonomy

A diverse assemblage of dinosaur and bird tracks from Niobrara County, Wyoming, represents the first vertebrate ichnofauna reported from the bone-rich Lance Formation (Maastrichtian, Upper Cretaceous). The ichnofauna includes a hadrosaur track with skin impressions; three theropod track types, including the tetradactyl track Saurexallopus zerbsti (ichnosp. nov.); a tridactyl dinosaur footprint with a fusiform digit III; possible Tyrannosaurus tracks; four distinctive avian ichnites; and invertebrate traces. The footprints are generally well-preserved and so offer a unique insight into the ecology of a small river valley during the Maastrichtian.

Saurexallopus zerbsti ichnosp. nov. from the Lance is similar to Saurexallopus lovei recently reported from the Maastrichtian, Harebell Formation, of northwestern Wyoming, but is represented by much better material, facilitating amendment of the ichnogenus. Skeletal equivalents for Saurexallopus are not currently known. Similarly, the tridactyl track with fusiform digit III is similar to footprints reported from the coeval Laramie Formation of Colorado and may also be similar to ichnogenus Ornithomimipus from the Edmonton Group of Alberta (though not necessarily of ornithomimid affinity). The hadrosaurian track with the skin impression is reminiscent of a similar ichnite reported from the Maastrichtian, St. Mary River Formation in Alberta, which is herein named Hadrosauropodus langstoni as part of a reassessment of Cretaceous ornithopod track ichnotaxonomy. Such correlations demonstrate the utility of tracks for local or regional biostratigraphy (palichnostratigraphy) in western North America. It is also clear that tracks add to our knowledge of the composition and distribution of dinosaurian and avian components of Maastrichtian faunas. In particular the bird tracks indicate a diversity of at least four species, one of which was a semi-palmate form, hitherto unknown in the ichnological record and named Sarjeantichnus semipalmatus.     

Deux nouveaux sites à traces de pas dinosauroïdes dans la Formation Dolomitique de l’Hettangien de Lozère,Languedoc-Roussillon,France

Recent ichnological studies revealed two new localities showing dinosaur footprints in the Hettangian Dolomitic Formation from the Causses Basin, southern France. The traces are reported from the northern part of the basin, in Lozère, an area where Lower Jurassic dinosaur ichnites were poorly documented. The surfaces bearing footprints are characterized by a large number of traces. The ichnites are ascribed to Grallator (Hitchcock, 1858), Dilophosauripus (Welles, 1971) and Eubrontes (Hitchcock, 1845) whose trackmakers were theropods. Although numerous tracksites were previously described in the southern part of the Causses Basin, these three ichnotaxa are for the first time observed in association into the Dolomitic Formation.     

Probable Relationships between the Lower Jurassic Crocodilomorph Trackways Batrachopus and Selenichnus: Evidence and Implications Based on New Finds from the St. George Area Southwestern Utah

Some small and medium-sized crocodylomorph footprints are described from the Late Jurassic (Kimmeridgian) coastal and deltaic units of the northern Spain (Asturias). There are at least four footprint morphotypes. Three of them, with well preserved trackways, are included in the ichnogenus Crocodylopodus (Crocodylopodus isp. and Crocodylopodus meijidei); the fourth one, documented by some isolated large footprints, is referable to the ichnogenus Hatcherichnus. This ichnoassociation confirms the presence of small crocodilians in palaeoenvironments apparently dominated by dinosaurs. The presence of Hatcherichnus seems to confirm the affinity between the Iberian and North American ichnofaunas.     

Tetradactyl footprints of an unknown affinity theropod dinosaur from the Upper Jurassic of Morocco

Background

New tetradactyl theropod footprints from Upper Jurassic (Oxfordian-Kimmeridgian) have been found in the Iouaridène syncline (Morocco). The tracksites are at several layers in the intermediate lacustrine unit of Iouaridène Formation. The footprints were named informally in previous works “Eutynichnium atlasipodus”. We consider as nomen nudum.

Methodology/Principal Findings

Boutakioutichnium atlasicus ichnogen. et ichnosp. nov. is mainly characterized by the hallux impression. It is long, strong, directed medially or forward, with two digital pads and with the proximal part of the first pad in lateral position. More than 100 footprints in 15 trackways have been studied with these features. The footprints are large, 38–48 cm in length, and 26–31 cm in width.

Conclusions/Significance

Boutakioutichnium mainly differs from other ichnotaxa with hallux impression in lacking metatarsal marks and in not being a very deep footprint. The distinct morphology of the hallux of the Boutakioutichnium trackmaker –i.e. size and hallux position- are unique in the dinosaur autopodial record to date.