辽宁西部晚中生代地层研究之进展及存在问题——辽宁西部晚中生代地层和鱼群研究之四

辽宁西部晚中生代地层的综合层序为:义县组、九佛堂组、沙海组/张老公屯组、阜新组和孙家湾组.中西部朝阳—喀左—建昌以及凌源—三十家子盆地的义县组大致相当于东部阜新—义县—锦州盆地的狭义义县组及其底部的北票尖山含化石沉积夹层;中西部的九佛堂组则可与东部的金刚山、吐呼鲁和九佛堂三个岩组相对比;张老公屯组火山岩在层序上大部分可能位于九佛堂组和阜新组之间.以北票鲟、中华弓鳍鱼和狼鳍鱼为代表的鱼类化石普遍见于中国北方热河群及其相当岩群的下部河湖相地层中,以粒鳞鱼、固阳鱼和副狼鳍鱼为代表的鱼类化石多见于上部的扇三角洲和湖沼相含煤地层中.热河群及相当岩群时代的确定以及陆相侏罗—白垩系界线的厘定受制于目前地层和生物化石的研究程度.从鱼群的面貌看,义县—九佛堂组、沙海—阜新组及相当地层的时代可能分别为晚侏罗世晚期—早白垩世早期和早白垩世中期.     

豫西马市坪盆地早白垩世热河昆虫群的发现及其地层学意义*

热河生物群是保存最好的白垩纪陆地生物群, 是世界上最重要的特异埋藏化石宝库之一。热河生物群的三阶段演化学说认为该生物群在第二演化阶段往南至秦岭、大别山一带, 包括河南西部和南部地区。早期研究记录表明河南西部地区产出热河生物群的代表分子三尾拟蜉蝣化石。本文首次报道了河南西部南召县马市坪盆地南召组衍蜓科稚虫化石, 并对其形态特征进行了简要描述, 同时报道了与之伴生的三尾拟蜉蝣稚虫化石。衍蜓科稚虫是热河生物群的代表化石之一, 先前均记录于辽宁西部义县组及相当地层, 属于热河生物群第二演化阶段的特征分子。河南西部新发现的昆虫化石证实了热河生物群在其第二演化阶段已经到达该地区。同时, 本研究确定马市坪盆地南召组可与辽宁西部义县组相对比, 南召组的地质时代属于早白垩世而非晚侏罗世。     

High-precision Ar/Ar age for the Jehol Biota

Abundant fossils of the terrestrial Jehol Biota, including plants, insects, dinosaurs, birds, mammals and freshwater invertebrates, were discovered from the Yixian Formation and the overlying Jiufotang Formation in Inner Mongolia, Hebei Province and Liaoning Province, northeastern China. Because of the exceptional preservation of fossils, the Jehol Biota is one of the most important Mesozoic lagerstätten and is referred to as a “Mesozoic Pompeii”. The Jehol Biota has provided a rare opportunity to address questions about the origin of birds, the evolution of feathers and flight, the early diversification of angiosperms and the timing of placental mammal radiation. Six tuff samples and two basalt samples collected from the Tuchengzi, the Yixian and the Jiufotang formations near the classic outcrops in western Liaoning, NE China yielded high-precision ⁴⁰Ar/³⁹Ar ages. We obtain an age of 129.7 ± 0.5 Ma for a basaltic lava from the bottom of the Yixian Formation and an age of 122.1 ± 0.3 Ma for a tuff from the lowermost part of the overlying Jiufotang Formation. Our age results provide an age calibration of the whole Yixian Formation and show that the whole formation was deposited entirely within Early Cretaceous time over an interval of ~ 7 Ma.     

A new species of Baiera from the Early Cretaceous Jehol Biota of southeastern Jilin,China

The Early Cretaceous Yingzuilazi Formation is exposed in the Baishan Basin, Baishan region of the southeastern Jilin Province, China. So far, no reports on fossil plants from this formation have been published. During recent field excursions, abundant faunal remains belonging to the Early Cretaceous Lycoptera–Ephemeropsis–Eosestheria assemblage of the Jehol Biota and numerous fossil plants were collected from the lacustrine beds of the lower part of this formation. A new species of Ginkgoales from this formation, Baiera baishanensis n. sp., is described based upon the leaf morphology and epidermal characters. This is the first report about fossil plants from the Yinzuilazi Formation, the easternmost distribution area of the Jehol Biota. The discovery of the new species extends significantly the stratigraphic and geographic distribution of Baiera in the Early Cretaceous Jehol Biota as well as the Eurasia. It also shows that Baiera was a common member of Ginkgophytes once lived in the Early Cretaceous deciduous forest of Northeast China. The new species also improves our knowledge on understanding the leaf morphology, epidermal features, and diversity of Baiera during the Early Cretaceous. Analysis of the epidermal characters of the new species and other associated plants reveals that the plants grew in a warm and humid climate in the temperate zone. The presence of some deciduous plants, including gingkgoaleans, czekanowskialeans, and some conifers, demonstrates a climate with seasonal fluctuations and precipitation.     

内蒙古海拉尔盆地白垩纪生物地层研究进展

兴安岭群龙江组产Ephemeropsistrisetalis等热河生物群分子,九峰山组产富含Cicatricosisporites,Pilosisporites,Concavissimisporites的孢粉组合,兴安岭群龙江组、甘河组火山岩同位素年龄为105-141Ma,证实兴安岭群的时代为早白垩世早期;扎赉诺尔群中以Cypridea,Limnocypridea,Ilyocyprimorpha和Hailaeria等属为代表的介形类动物群,以Nyktericysta,Vesperopsis等属为代表的NV浮游植物群,以富含Lygopodiaceae科各属孢子,尤其是Cicatricosisporites高含量的孢粉组合,代表了中国北方早白垩世特有的动、植物群面貌,而其中Asteropollis,Tricolpites和Polyporites等被子植物花粉化石的发现,这一事实似乎暗示了扎赉诺尔群的时代为早白垩世中、晚期;青元岗组产以Talicypridea,Altanicypris,Chinocypridea和Harbinia为代表的介形类动物群,具有显著的地域性特点,可与松辽盆地四方台组对比,其时代为晚白垩世Maastrichtian期。     

Discovery of the Jehol Biota from the Celaomiao region and discussion of the Lower Cretaceous of the Bayingebi Basin,northwestern China

Some typical components of the Jehol Biota, including conchostracans Eosestheria sp., the mayfly Ephemeropsis trisetalis Eichwald, 1864, the aquatic beetle Coptoclava longipoda Ping, 1928, and a fragmentary dragonfly, are reported for the first time from the Bayingebi Formation in the Celaomiao region, western Inner Mongolia, China. This discovery indicates that the middle Upper Member of Bayingebi Formation can be correlated with the upper Yixian and the lower Jiufotang formations in western Liaoning Province. Combining it with the radio-isotopic dating result, we further believed that the Upper Member of Bayingebi Formation could be roughly correlated with the Yixian, Jiufotang, and Shahai formations, and the overlying Suhongtu Formation with the Fuxin Formation in western Liaoning Province.In the major Bayingebi Basin, palaeontological and radio-isotopic dating evidence shows that the Bayingebi Formation has a long depositional history of over 30 Ma: its Upper Member bearing the Jehol Biota and the early Fuxin Biota is probably coeval to the Yixian, Jiufotang and Shahai formations and has a Barremian–early Albian age; its Lower Member may be Berriasian–Hauterivian in age and could be correlated with the upper Tuchengzi, Zhangjiakou, and Dabeigou formations in northern Hebei Province. This suggests that the Bayingebi Formation should be promoted to the stratigraphic rank of group and subdivided into several secondary units (formations). Unlike the previous result, the Yingen Formation is considered across the Lower Cretaceous–Upper Cretaceous boundary and being late Albian–early Turonian in age.     

辽宁凌源及内蒙古宁城地区下白垩统义县组脊椎动物生物地层

辽宁凌源及相邻内蒙古南部宁城地区义县组发现多个重要脊椎动物化石地点,通过岩 石地层、脊椎动物生物地层和同位素年代地层对比,建立了该地区义县组地层层序。凌源一宁 城地区义县组有 ２个脊椎动物化石层位：下部道虎沟层含 Ｌｙｃｏｐｔｅｒａｅｒ Ｉｃｈｔｈｙｏｆａｕｎａ, Ｐｓｉｔｔａｃｏｓａｕｒｕｓ Ｆａｕｎａ和Ｃｏｎｆｕｃｉｕｓｏｒｎｉｓ Ａｖｉｆａｕｎａ等３个动物群,可以与北票尖山沟层的四合 屯脊椎动物化石群对比,层位相当于义县组一、三段;上部大王杖子（大新房子）层含 Ｌｙｃｏｐｔｅｒａ Ｉｃｈｔｈｙｏｆａｕｎａ和Ｌｉａｏｘｉｏｒｎｉｓ Ａｖｉｆａｕｎａ等２个动物群,为义县组中部沉积,在四合屯地 区缺失。冀北丰宁四岔口－森吉图地区义县组脊椎动物化石层对应于凌源大王杖子层;滦平 大北沟组为义县组最下部沉积,其上覆的大店子组相当于宁城道虎沟层和北票四合屯义县组 一、三段。热河群义县组和九佛堂组发现３个连续的鸟类群;义县组下部Ｃｏｎｆｕｃｉｕｓｏｒｎｉｓ Ａｖｉｆａｕｎａ、义县组中部Ｌｉａｏｘｉｏｒｎｉｓ Ａｖｉｆａｕｎａ和九佛堂组Ｃａｔｈａｙｏｒｎｉｓ－Ｃｈａｏｙａｎｇｉａ Ａｖｉｆａｕｎａ。义 县组和九佛堂组Ｌｙｃｏｐｔｅｒａ　Ｉ     

Basal titanosauriform (Dinosauria, Sauropoda) teeth from the Lower Cretaceous Yixian Formation of Liaoning Province, China

The Yixian Formation of Liaoning Province, People's Republic of China has yielded a diverse fauna of non-avian dinosaurs, but is dominated by small-bodied taxa. Here, we describe a series of isolated teeth from the Lujiatun Beds of the formation that are referable to a basal titanosauriform sauropod. Some of the teeth possess a distinctive circular boss on the lingual surface, which suggests that they are referable to cf. Euhelopus sp. This identification provides some additional support for biostratigraphical correlations between the Jehol Group and the Mengyin Formation of Shandong Province that suggest an Early Cretaceous age for the latter unit. Moreover, the titanosauriform affinities of the teeth provide further evidence for the dominance of this sauropod clade in eastern Asia during the Cretaceous.     

Male spike strobiles with Gnetum affinity from the Early Cretaceous in western Liaoning, Northeast China

A fossil with Gnetum affinity was found in the Jianshangou Member (Barremian Age) of the Yixian Formation (Lower Cretaceous Epoch) of the Jehol Group in western Liaoning, northeastern China. The single fossil specimen is represented by both elongate-cylindrical male spike strobiles which borne within a nodal bract of cauliflorous branch. The spike strobiles have apparent nodes, invisible internodes, and numerous verticillate involucral collars. The microsporangiate units within involucral collars are not seen. The male spike strobiles with verticillate involucral collars occur exclusively in Gnetum; hence, the fossil strobiles are attributed to a new taxon, Khitania columnispicata gen. & sp. nov., being closely related to Gnetum. The general isotopic dating suggests an age of Barremian, ca. 125-122 million years (Myr) ago for the Jianshangou Member. The palaeoecological and palaeoclimatic inference based on the compositions of flora and fauna, and lithological characters of the fossil locality suggests that the fossil plants grew in a subtropical mesophytic forest and under a warmer climate. The remains of male spike strobiles are the first record of gnetalean macrofossil. It documents the evolution of the distinct gnetoid morphology and indicates a wider range of distribution of Gnetaceae in the Early Cretaceous than present day.     

A sauropod rib with an embedded theropod tooth: direct evidence for feeding behaviour in the Jehol group,China

Xing, L, Bell, P.R., Currie, P.J., Shibata, M., Tseng, K. & Dong, Z. 2012: A sauropod rib with an embedded theropod tooth: direct evidence for feeding behaviour in the Jehol group, China. Lethaia, Vol. 45, pp. 500–506. A fragmentary rib from the Lower Cretaceous (Barremian) Yixian Formation in northeastern China preserves rare, direct evidence of feeding behaviour by an unidentified theropod. The rib, which comes from the holotype of Dongbetitan, preserves an embedded, broken theropod tooth. Comparison of the tooth with all known theropods from the Yixian Formation suggests that it belongs to a new taxon of medium‐sized theropod. Given the large size difference between the sauropod and the theropod and the absence of reactive bone growth around the tooth, the bite likely occurred post‐mortem during scavenging. Recognition of a new, medium‐sized theropod increases the known diversity of taxa from the Yixian Formation and helps fill a gap in the theropod palaeoecology of that formation, which previously consisted of only small (<2 m) forms. □China, Cretaceous, feeding behaviour, theropod, titanosauriformes, sauropod.     

New basal eutherian mammal from the Early Cretaceous Jehol biota,Liaoning, China

A new genus and species of eutherian mammal, Acristatherium yanensis gen. et sp. nov., is described from the Early Cretaceous Jehol biota, China. The new taxon is based on a partial skull that is preserved in three dimensions from the Lujiatun bed of the Yixian Formation and dated 123.2±1.0 Ma. Its right upper and lower dentitions are nearly complete and it has a dental formula 4.1.5.3/3.1.5.3. The new mammal reveals several craniodental characteristics of Early Cretaceous eutherians previously unknown in fossil records of therians, such as a possible vestige of the septomaxilla. The craniodental features of the new taxon are compared with those of relevant Early Cretaceous eutherians and therians. Phylogenetic analyses based on a data matrix containing 70 taxa and 408 characters place A. yanensis as the most basal eutherian in the selected group. The morphological differences between Acristatherium and Eomaia indicate that eutherians already had a significant degree of generic diversification ca 125 Ma.     

辽宁早白垩世义县组一原始鸟脚类恐龙

初步记述了采自辽西地区早白垩世义县组新的原始鸟脚类恐龙化石材料,并依此建立一新属新种上园热河龙（Jeholosaurus shangyuanensis gen. et sp. nov.）。化石产于北票市上园镇陆家屯义县组下部第一段灰白色凝灰质砂岩中,同一层位产出过大量鹦鹉嘴龙化石。上园热河龙的主要鉴定特征包括6个前上颌齿,鼻骨背面发育小孔,前齿骨约为前上颌骨主体长度的1.5倍、未发育股骨前髁间沟、骨不在一平面上,第三趾趾节中第四节最长。上园热河龙具有一些真鸟脚类恐龙的近裔性状,比如眶前孔小,方骨孔大,位于方颧骨侧面,外下颌孔缺失。另外,上园热河龙的股骨近端形态非常接近进步的鸟脚类恐龙。但是上园热河龙发育有6个前上颌齿,上下颌关节处与齿列位于同一水平线,前上颌齿列与上颌齿列位于同一水平线,这些原始特征未见于已知鸟脚类恐龙。上园热河龙确切系统分类位置需要进一步确定。 上园热河龙是义县组中发现的第二种鸟臀类恐龙,增加了这类恐龙在热河生物群中的分异度。     

辽西下白垩统热河群一新微型驰龙类恐龙和热河生物群驰龙类的生态位分化

早白垩世热河生物群的驰龙类恐龙在分类和形态上多样化程度很高,其中的赵氏小盗龙曾被认为是已知体型最小的非鸟兽脚类恐龙之一.然而这个观点依据的标本都处于相对早期的生长发育阶段,因此热河生物群驰龙类恐龙的体型下限仍不明确.本文依据一件产白辽宁省凌源县四合当下白垩统义县组(热河群中部)的标本,描述驰龙类一新种,杨氏钟健龙.这一新种可归入小盗龙类,但它在很多特征上不同于其他小盗龙类,其中最明显的区别是其相对长的钩状突愈合于背肋上,肱骨具有强烈内倾的近端,肱骨三角嵴上有一窗孔,尺骨略长于肱骨,并具有窄跖型的足.最重要的是,已为成年个体的杨氏钟健龙正模估计体重约为0.31 kg,这证实了热河生物群的一些驰龙类恐龙属于已知体型最小的非鸟恐龙.初步分析显示热河生物群驰龙类恐龙有生态位分化的情况,这一现象在中生代恐龙动物群中报道很少.     

A new odonatan (Stenophlebiidae) from the Lower Cretaceous Sinuiju Formation of North Phyongan Province,the Democratic People’s Republic of Korea

A new fossil species, Stenophlebia ryonsangensis n. sp. (Stenophlebiidae), collected from the Lower Cretaceous non-marine Sinuiju Formation, North Phyongan Province, has the following forewing characters: preserved wing slender and longer than 47.1 mm; Cr long, with three cells below it, and well aligned with distal part of ScP; Sn shorter than Cr, one cell long; supplementary veinlet below Sn aligned with RP2 and about two cells long; base of IR1 five cells distal of base of RP2. This well preserved material is the first odonatan reported in the DPRK. Congeneric species has previously been found in the Lower Cretaceous Yixian Formation of western Liaoning Province, Northeast China, thus the new discovery of Stenophlebia ryonsangensis n. sp. may contribute to evaluating the distribution and migration of Stenophlebidae and may further indicate the close relationship of the fossil layer with the famous Jehol Biota in Northeast China.     

Mesozoic leaf beetles of the tribe Mesolpinini trib. nov. (Coleoptera,Chrysomelidae) from the Lower Cretaceous

This publication is based on recent studies of Lower Cretaceous leaf beetles from the Yixian Formation (Liaoning, China), which are represented by five new species of one new genus Mesolpinus gen. nov. (M. antenattus sp. nov. [type species], M. adapertilis sp. nov., M. angusticollis sp. nov., M. basicollis sp. nov., and M. trapezicollis sp. nov.) assigned to a new tribe, Mesolpinini trib. nov. of the subfamily Chrysomelinae. This tribe, which includes only species from the Jehol biota, is the oldest known group of the family in the fossil record. A key to species of the genus Mesolpinus gen. nov. is provided and the position of the new tribe is discussed. A brief overview of the Mesozoic data on the subfamily Chrysomeloidea is given.     

A whole-plant monocot from the Lower Cretaceous

The Yixian Formation (the Lower Cretaceous) of China is world famous for its fossils of early angiosperms. Despite their great diversity, few of these fossils are preserved as whole plants, making our understanding of early angiosperms incomplete. Here, we report a fossil angiosperm, Sinoherba ningchengensis n. gen. n. sp. (Sinoherbaceae n. fam.), from the Yixian Formation of China. The fossil is of a whole plant, including physically connected root with fibrous rootlets, a stem with branches and nodes, leaves with parallel-reticulate veins, and a panicle of female flowers with an ovary surrounded by perianth. Morphological and phylogenetic analyses reveal that Sinoherba is an herbaceous monocot. This fossil underscores the great diversity of angiosperms in the Lower Cretaceous Yixian Formation and an earlier, pre-Cretaceous origin of angiosperms.     

U–Pb SHRIMP age for the Tuchengzi Formation,northern China,and its implications for biotic evolution during the Jurassic–Cretaceous transition

The Late Jurassic–Early Cretaceous Tuchengzi Formation is widespread in North China. Its clastic deposits indicate a tropical, dry, and hot paleoclimate, different from the subtropical, humid, and seasonal climate in the early Middle Jurassic. The sudden environmental change from the Middle to Late Jurassic resulted in a rapid disappearance of the Yanliao/Daohugou Biota, with more than 90% of the species of the Yanliao/Daohugou Biota dying out and replaced by the Early Cretaceous Jehol Biota. Eolian sandstones with large-scale cross-bedding occur within the uppermost part of the Tuchengzi Formation in North China. The sandstones are stratigraphically higher than the tuff previously dated as 139 Ma. We obtained two SHRIMP zircon U/Pb ages from the tuff beds. One sample was collected from the tuff in the basal Tuchengzi Formation in northern Hebei and the other from the tuff intercalated in the eolian cross-bedded sandstones in the uppermost Tuchengzi Formation in western Liaoning. Our results show that 154 Ma is the oldest age constraint for the Tuchengzi Formation and 137 Ma is the youngest age estimate of the formation, providing an age constraint for the transition from the Yanliao Biota to the Jehol Biota.     

LATE MESOZOIC FISH FAUNA FROM WESTERN LIAONING, CHINA

Thelycopteridsarecharacterizedbythefollowingcombinationoffeatures:na-salstube-like,andseparatedbymesethmoid;temporalfenestrapresentonposterola-teralregionofcranium;hyomandibularwithadistinctanteroventralprocess;ant-orbitalsemicircularinshape,4-5infraorbitalbones,nosupraorbital;innermarginofpectoralfinwithalargeunbranchedray;afullneuralspinepresentonfirstpreuralcentrum,nomorethanoneepural,6-7hypurals,3-5uroneurals;cycloidscaleswithfineconcentriccirculiandwithbasalradii.Amongthenominatedgenerawhi…     

热河生物群凌源东方叶肢介的软体构造及其分类意义

东方叶肢介（Eosestheria）是著名热河生物群中最为常见的一类甲壳动物,关于它的形态、壳瓣结构及微细纹饰特征的研究已相当详尽,但一直没有关于其软体构造的报道。本文描述的凌源东方叶肢介（Eosestheria lingyuanensis）采自辽宁北票市尖山沟村,产于下白垩统义县组的尖山沟夹层。这些软体构造包括：头部...