A theropod track assemblage including large deinonychosaur tracks from the Lower Cretaceous of Asia

A total of more than 40 tridactyl and didactyl tracks were preserved as natural casts on four fallen blocks of sandstone representing the Lower Cretaceous Jiaguan Formation of Gulin County in southeastern Sichuan Province, China. While several trackways can be distinctly followed, others are isolated imprints only. All have been flattened by overburden pressures. Tridactyl tracks are present with three size-classes being <10 cm, 10–20 cm and >20 cm in length. Morphologically they are similar to the ichnogenus Eubrontes, considering the relatively weak mesaxony. Eight of the tracks on one of the blocks are clearly didactyl and are here interpreted as representing large and medium sized dromaeosaurids. The largest track is about ∼30 cm long and comparable in size to the type of Dromaeopodus (∼28 cm), from the Lower Cretaceous of Shandong Province, which was the largest dromaeosaurid track previously reported. This report adds new data to the growing number of dromaeosaurid tracksites reports from China, and from the Jiaguan Formation, suggesting that this theropod group had a preference for fluvial paleoenvironments.     

New ornithopod footprints from the Lower Cretaceous Kitadani Formation,Fukui, Japan: Ichnotaxonomical implications

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.     

A diverse saurischian (theropod–sauropod) dominated footprint assemblage from the Lower Cretaceous Jiaguan Formation in the Sichuan Basin,southwestern China: A new ornithischian ichnotaxon,pterosaur tracks and an unusual sauropod walking pattern

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.     

Theropod assemblages and a new ichnotaxon Gigandipus chiappei ichnosp. nov. from the Jiaguan Formation,Lower Cretaceous of Guizhou Province,China

A newly discovered Jiaguan Formation(Lower Cretaceous) tracksite from the Linjiang region of Guizhou Province, China, reveals the first example of a Cretaceous track morphotype attributable to the non-avian theropod ichnogenus Gigandipus, here named Gigandipus chiappei ichnosp nov. The theropod dominated locality also reveals the second report of the avian theropod ichnogenus Wupus, one of the largest avian traces currently known from the Lower Cretaceous. The Linjiang site provides evidence to support previous interpretations of a distinctive Lower Cretaceous theropod-dominated ichnofauna that was widespread in China and East Asia and highlights the similarity between Lower Cretaceous theropod ichnotaxa in East Asia and those found in the Lower Jurassic both in East Asia and elsewhere. These similarities in turn create various ichnotaxonomic challenges familiar to researchers working on theropod tracks, and we recommend caution in the naming of new theropod ichnotaxa at the ichnogenus level.     

Sauropod Teeth from the Lower Cretaceous Luohandong Formation of Ordos Basin, Inner Mongolia

The Early Cretaceous Zhidan Group in the northern Ordos Basin, Inner Mongolia, yielded a large number of tetrapods, including turtles, choristoderes, crocodyliforms, psittacosaurs, stegosaurs, theropods and birds. Well-preserved sauropod teeth have been found in the Luohandong Formation, a middle-upper unit of the Zhidan Group. The large V-shaped wear facet, low slenderness index value, labial grooves, lingual ridge and concavity on the tooth crown suggest that these teeth are from titanosauriforms. Moreover, the presence of the prominent bosses on the lingual side of the tooth crown indicates these teeth should be identified as Euhelopus teeth further. The existence of Euhelopus in Ordos Basin (Inner Mongolia), Shandong Province and western Liaoning Province shows some connections about vertebrate faunas during Early Cretaceous in these areas. Other tetrapod groups such as turtles (Sinemys, Ordosemys), choristoderes (Ikechosaurus), psittacosaurs (Psittacosaurus) and birds (Cathayornis) provide more evidences for this viewpoint.     

Morphology and phylogenetic origin of the spinicaudatan Neodiestheria from the Lower Cretaceous Dalazi Formation,Yanji Basin,north-eastern China

The spinicaudatan Neodiestheria Chen is an important component of the diverse Early Cretaceous Yanjiestheria fauna in eastern Asia. Examination under a scanning electron microscope of newly collected and well-preserved specimens of Neodiestheria dalaziensis Chen from the Albian Dalazi Formation of Zhixin, Jilin Province, north-eastern China, has revealed morphological features of the carapace not recognized previously, namely that puncta are not only evenly distributed on growth bands near the umbo and gradually merge into a punctate fine reticulation and dense radial lirae on each growth band in the upper-middle part of the carapace, but also occur on growth lines and within the lumina of a fine reticulum, and between radial lirae on growth bands in the middle and lower parts of the carapace. Growth bands in anteroventral, ventral and posteroventral parts of the carapace are also ornamented with transversely elongate large pits (depressions) surrounded by swellings, appearing as a large reticulum superimposed over fine reticulation and radial lirae. These ontogenetically developing morphological patterns on the growth bands of the juvenile stage of the carapace indicate that Neodiestheria is closely related phylogenetically to Triglypta Wang.     

吉林延边地区早白垩世长财组的蕉羽蕨叶(Nilssoniopteris)

首次在吉林省延边地区长财煤矿早白垩世长财组发现蕉羽蕨叶属(Nilssoniopteris)。根据其外部形态及表皮构造等特征,鉴定并描述蕉羽蕨叶4个种,即：普里纳达蕉羽蕨叶Nilssoniopteris prynadae Samylina,平轴蕉羽蕨叶(新联合)N.platyrachis (Samylina) comb．nov．长叶蕉羽蕨叶?N.longifliadenko?和蕉羽蕨叶(未定种)Nilssoniopteris sp。     

内蒙古鄂尔多斯盆地下白垩统罗汉洞组剑龙类化石新材料

鄂尔多斯盆地下白垩统志丹群产出丰富的四足类动物化石:龟类、离龙类、鳄形类、鹦鹉嘴龙类、剑龙类、甲龙类、兽脚类、鸟类和早期哺乳类。采自内蒙古杭锦旗老龙豁子志丹群罗汉洞组剑龙类关联的荐椎与肠骨化石新标本,其形态特征显示该标本可被归为鄂尔多斯乌尔禾龙(Wuerhosaurus ordosensis)。该标本解剖学研究表明,鄂尔多斯乌尔禾龙腰带还具有以下特征:上髋臼面前缘向后凹而后缘内侧更加内凹。鄂尔多斯乌尔禾龙(Wuerhosaurus ordosensis)和新疆准噶尔盆地的平坦乌尔禾龙(Wuerhosaurus homheni)在腰带上存在明显区别:(1)鄂尔多斯乌尔禾龙肠骨前突延伸较短,肠骨前突背缘向后逐渐向背侧拱曲、高度逐渐加大,而平坦乌尔禾龙肠骨前突后端背腹缘大致平行;(2)鄂尔多斯乌尔禾龙上髋臼面较小;(3)鄂尔多斯乌尔禾龙左右肠骨前突延伸方向与中轴线之间的夹角略小于平坦乌尔禾龙。这些区别进一步表明,鄂尔多斯乌尔禾龙和平坦乌尔禾龙是不同的种。     

二连盆地白音查干凹陷下白垩统阿尔善组-都红木组层序地层

层序地层学是岩性-地层油气藏勘探研究的核心技术之一。为深入开展二连盆地白音查干凹陷岩性-地层油气藏勘探,在前人研究成果基础上,通过研究区200多口井的精细地层对比和33口井759.42 m岩心的详细观察及区域构造-沉积演化分析,综合运用构造、古生物、岩性、测井以及地震反射等5个方面的特征,对白音查干凹陷(主要是西部次凹)油气勘探的主要目的层下白垩统阿尔善组—都红木组的层序发育特征进行再认识,对层序界面的性质进行重新厘定。将白音查干凹陷下白垩统阿尔善组—都红木组划分为2个超长期层序(分别对应于阿尔善组—腾格尔组和都红木组)和5个长期层序(分别对应于阿尔善组一段、阿尔善组二段、腾格尔组、都红木组一段和都红木组二段~三段);提出白音查干凹陷下白垩统腾格尔组长期层序的底界面为一连续沉积的整合面,不能构成油气运移的良好通道,即在腾格尔组底部即使圈闭条件良好(如锡40井—锡43井区),但也会因缺乏良好的油气运移通道致使圈闭中供油不足而不能成藏。     

辽宁省四合屯下白垩统义县组的兽脚类足迹化石和可能的造迹者

记述了辽宁省四合屯下白垩统义县组三个半恐龙足迹,归入似鹬龙足迹（亦译为跷脚龙足迹）一未定种（Grallator isp.）。这是义县组恐龙足迹化石的首次描述。该行迹至少由3个造迹者所造。从足迹推断恐龙体长1.51m,属于义县组兽脚类恐龙较为普遍的体长范围。重建了尾羽鸟(Caudipteryx)和中华龙鸟(Sinosauropteryx)的足部,前者的足迹轮廓与似鹬龙足迹未定种的吻合度超过后者。根据化石记录,似鹬龙足迹类型可能广泛存在于义县组的各种中小型兽脚类（驰龙类与伤齿龙类除外）中。     

The longest theropod trackway from East Asia,and a diverse sauropod-, theropod-, and ornithopod-track assemblage from the Lower Cretaceous Jiaguan Formation,southwest China

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.     

黑龙江省勃利盆地东部坳陷下白垩统穆棱组古环境恢复

勃利盆地东部坳陷下白垩统穆棱组暗色泥岩发育,通过对勃利盆地Zk2钻井岩芯观察及对暗色泥岩样品进行稀土、微量元素含量变化的分析,恢复了穆棱组沉积时期的古环境。结果显示:研究区穆棱组沉积相以三角洲平原、三角洲前缘和半深湖沉积亚相为主,穆棱组沉积初期气候特征以温暖湿润为主,中期气候变为半湿半干,盐度增加但仍是淡水沉积环境,穆棱组中晚期气候由干旱炎热气候逐步变为温暖湿润气候。穆棱组沉积时期气候总体呈温暖湿润-半湿半干-温暖湿润变化的规律。     

Large-Sized Ankylosaur (Dinosauria) from the Lower Cretaceous Jiufotang Formation of Western Liaoning, China

Two incomplete bones referred to ankylosaur scapulocoracoid and humerus are described, which were discovered from the Early Cretaceous Jiufotang Formation of Dachengzi Town, Kazuo County, Liaoning Province. Ankylosaur dinosaurs have ever been found in the Lower Cretaceous Yixian, Fuxin and Sunjiawan Formations of western Liaoning. The occurrence of ankylosaurs within Jiufotang Formation improves our knowledge on the ankylosaur stratigraphic distribution. Based on the length of scapulocoracoid, the new dinosaur is estimated to exceed 6.0 meters long, representing the largest ankylosaur in western Liaoning.     

吉林省松江盆地下白垩统大砬子组上段浊积岩沉积特征及地质意义

松江盆地为一中生代山间沉积盆地,盆地内大砬子组上段普遍发育浊流沉积。通过对浊积岩体的沉积环境特征、岩性特征、沉积构造特征、粒度结构特征及层序特征等进行的研究表明:发育于盆地扩张时期的大砬子组上段浊积岩具有稳定型浊积岩的沉积特征,并将其划分为中心微相及边缘微相。应用沉积岩碎屑物质成分对浊积岩进行统计并结合前人的研究成果表明,大砬子上段沉积时期,源区构造背景为稳定陆块区,构造环境较为稳定。大量浊积岩所形成的岩性圈闭可构成良好的储集体。     

酒泉盆地营尔凹陷下白垩统下沟组沉积体系研究

根据对营尔凹陷下沟组岩心、测井和地震资料的分析,运用现代沉积学、层序地层学理论,将营尔凹陷下白垩统下沟组划分为4个三级层序。营尔凹陷下沟组主要发育辫状河三角洲、扇三角洲、近岸水下扇、远岸水下扇、滑溻浊积体、湖泊共6种沉积相类型,形成不同类型砂体。三角洲前缘亚相及远岸水下扇沉积相砂岩发育,砂岩物性较好,具备储集空间且储盖组合条件好,有利于油气成藏。三角洲平原亚相及近岸水下扇以粗碎屑沉积为主,砂泥分异差,储集物性差,难以形成油气藏。有利沉积相带空间展布与构造的配置关系决定了油气富集高产区的空间分布。     

Palynochronology of Lower Cretaceous volcano-sedimentary succession of the Rajmahal Formation in the Rajmahal Basin, India

In the Rajmahal Basin Lower Cretaceous rocks are classified under the Rajmahal Formation. It includes a series of volcanic basalt flows and associated sedimentary intertrappean beds. Up to 15 basalt flows have been recorded in this basin. The intertrappean beds comprise sandstone, shale, siltstone, and clay deposits which are rich in spores and pollen. The palynoflora recovered from intertrappean beds shows definite pattern of evolution and diversification. On the basis of its overall composition, distribution pattern of age marker taxa and the First Appearance Datum of key taxa, four palynological assemblages have been identified. The chronology of these assemblages in ascending order is (1) Ruffordiaspora australiensis, (2) Foraminisporis wonthaggiensis, (3) Foraminisporis asymmetricus, and (4) Coptospora verrucosa. These assemblages ascertain the age of the volcano-sedimentary sequence of the Rajmahal Formation in the Rajmahal Basin as Berriasian to Aptian. The palynochronology of the intertrappean beds enables their correlation in the Rajmahal Basin. In different areas of the basin, the palynological dating of the lowermost intertrappean bed within the Rajmahal Formation which overlies the Dubrajpur Formation, has provided a Berriasian to Aptian age. The palynological assemblage indicating the Berriasian age is inferred as the time of the initiation of volcanic activity which continued up to the Aptian in the Rajmahal Basin.     

辽宁省四合屯下白垩统义县组的兽脚类足迹化石和可能的造迹者

记述了辽宁省四合屯下白垩统义县组三个半恐龙足迹,归入似鹬龙足迹（亦译为跷脚龙足迹）一未定种（Grallator isp.）。这是义县组恐龙足迹化石的首次描述。该行迹至少由3个造迹者所造。从足迹推断恐龙体长1.51m,属于义县组兽脚类恐龙较为普遍的体长范围。重建了尾羽鸟(Caudipteryx)和中华龙鸟(Sinosauropteryx)的足部,前者的足迹轮廓与似鹬龙足迹未定种的吻合度超过后者。根据化石记录,似鹬龙足迹类型可能广泛存在于义县组的各种中小型兽脚类（驰龙类与伤齿龙类除外）中。     

Didactyl raptor tracks from the Cretaceous,Plainview Sandstone at Dinosaur Ridge

Two natural casts of two-toed (didactyl) tracks from the Cretaceous (Albian) Plainview Sandstone (Plainview Member) of the South Platte Formation (Dakota Group) at Dinosaur Ridge, Colorado are attributed to deinonychosaurian theropod dinosaurs and placed in the ichnogenus Dromaeosauripus. This is both the first report of tracks from this unit in the Dinosaur Ridge area and the first report of deinonychosaurian tracks from Colorado. It is also only the third report of this track type from North America. The rarity of tracks from the Albian-aged, Plainview Sandstone (Dakota Group Sequence 2) contrasts with their abundance in the upper (Cenomanian) part of the overlying South Platte Formation (Dakota Group Sequence 3), which has yielded more than 120 sites mostly in Colorado, giving rise to the “Dinosaur Freeway” concept. As no deinonychosaurid tracks are known from the sequence 3 part of the South Platte Formation, despite the large vertebrate and invertebrate ichnological database available, it is evident that the sparse vertebrate ichnofauna from the Plainview Member (Sequence 2) is inherently different. This striking difference in both track abundance and track type reflects differences in both age and depositional environment. Based on the Albian age, and track type, the Plainview tracks invite comparison with the ichnofaunas of the Cedar Mountain Formation and not with those well-known from the upper part of the South Platte Formation known as the Dinosaur Freeway.     

Early-diverging Titanosauriform (Dinosauria, Sauropoda) Teeth from the Lower Cretaceous Yixian Formation of Southeastern Inner Mongolia, Northeast China

Three eusauropod teeth (SDUST-V1064, PMOL-AD00176, PMOL-ADt0005) are reported from the Lower Cretaceous Yixian Formation of Ningcheng, southeastern Inner Mongolia, China. Two of them (SDUST-V1064, PMOL-AD00176) are assigned to early-diverging titanosauriforms in having slightly mesiodistal expansion at the base of the tooth crown, a slenderness index value >2.0 and <4.0, and D-shaped cross section. Furthermore, SDUST-V1064 and PMOL-AD00176 are referred as an Euhelopus-like titanosauriform on the basis of having a sub-circular boss on the lingual surface and an asymmetrical crown-root margin which slants apically, respectively.     

黑龙江鸡西含煤盆地早白垩世城子河组特尔姆叶(Tyrmia)的发现

报道了本内苏铁类植物化石——特尔姆叶(Tyrmia)在黑龙江鸡西含煤盆地早白垩世城子河组的新发现。介绍了特尔姆叶属的研究简况。根据新发现化石的外部形态及角质层解剖等特征,建立了新种——鸡西特尔姆叶(Tyrmia jixiensissp.nov.),并讨论了其在研究鸡西含煤盆地早白垩世时期古气候及古环境的意义。