Solenites (Czekanowskiales) from the Late Mesozoic Jehol Biota of Southeastern Jilin,China and its Paleoclimatic Implications

Situated at the easternmost area of the Late Mesozoic Jehol Biota, China, abundant fossils, including invertebrates, vertebrates and plants, were collected from the Early Cretaceous Yingzuilazi Formation of the Baishan Basin, southeastern Jilin. The faunal remains from this formation distinctly belong to the Early Cretaceous Lycoptera-Ephemeropsis-Eosestheria assemblage of the Jehol Biota. Based on the gross leaf morphology and epidermal structures, two new species and one indeterminate species of genus Solenites （Czekanowskiales）, S. baishanensis sp. nov., S. gracilis sp. nov. and S. sp. are described in this paper. This is the first fossil plant of Czekanowskiales reported from this new fossil locality of the easternmost area of the Late Mesozoic Jehol Biota, China. The new discovery contributes to improve our knowledge for understanding of leaf morphology, epidermal characters and diversity of this genus during the Early Cretaceous time, and extends geologic and geographic distribution of Solenites in northern China and Eurasia. Along with consideration of associated plant and faunal assemblages and sedimentology, we suggest that the regional climate was warm and moderately humid with seasonal temperature and precipitation variations in warm-temperate zone during the Early Cretaceous.

New Fossil Beetles of the Family Ommatidae (Coleoptera: Archostemata) from the Jehol Biota of China

A new genus with one new species and five new species of genus Amblomma of fossil ommatids are described and illustrated： Euryomma tylodes gen. et sp. nov., Amblomma cyclodonta sp. nov., Amblomma miniscula sp. nov., Amblomma porrecta sp. nov., Amblomma eumeura sp. nov., and Amblomma protensa sp. nov. All of them were collected from the Upper Jurassic or Lower Cretaceous Yixian Formation of western Liaoning, China. A key to the species of Amblomma is given. The wide epipleural space shows that Euryomma may be a primitive genus in Ommatidae. Many different species of Amblomma occurred within the same sedimentary horizon in this area could be environmental changes caused by frequent volcanic activities during the deposition of the Yixian Formation.

A Mesozoic Pompeii: History of the Jehol Biota's Rise and Fall

The Jehol fauna was initially represented by a bony fish, concostracan and an insect, as a Lycoptera davidi-Eosestheria-Ephemeropsis trisetalis association,but since the researches of recent decades, the Jehol Biota is now completely different from the past low-diversity, and encompasses a native terrestrial biota that includes many well-preserved vertebrates, invertebrates and plants. There are more than 20 important biological categories, thousands of taphonomically unusual fossils, especially noted for the wide variety of biological tissues. The Jehol Biota has caused a sensation in the world with its wide distribution, large quantity, great variety, fine preservation and detailed information, which records the rise and fall of the numerous taxa, and provides significant evidence for three origins： of birds, eutherian mammals, and angiosperms. The Jehol Biota is a highlight of basic scientific research in China, and we honor it as a world-class fossil treasury and ＂a Mesozoic Pompeii＂.

A reassessment of Iteravis huchzermeyeri and Gansus zheni from the Jehol Biota in western Liaoning, China

The authors reassessed the taxonomic distinction of Iteravis huchzermeyeri and Gansus zheni,which are two species of Ornithuromorpha based on specimens from the same locality in western Liaoning and derive from the Jehol Biota.The detailed comparisons of the holotype and referred specimens of both species,reveal no anatomical features that distinguish these taxa as separate species.Some minor differences are considered to relate to ontogenetic or interspecific differences.The stratigraphic occurrence for both specimens is the Lower Cretaceous Jiufotang Formation.Accordingly,the authors conclude that Iteravis huchzermeyeri has priority,by 15 days,for this taxon and that Gansus zheni is a junior synonym.The diagnosis of Iteravis huchzermeyeri is revised based on further study on all specimens referred to this species.Its generic distinction from Gansus is maintained thereby removing a potential genus-level correlation linking Xiagou Formation in Gansu Province with the Jiufotang Formation in Liaoning Province.

The First Discovery of the Easternmost Jehol Biota from Southeastern Jilin, China

Objective The Jehol Biota, a world-famous Early Cretaceous fossil Lagersttate characterized by the traditional Eosestheria-Ephemeropsis-Lycoptera （EEL） assemblage, has a wide distribution over most parts of northem China, the coastal area of southeastem China, southeastem Mongolia, Transbaikalian area of Russia, Korea and Japan （Shao et al., 2017）. The Baishan Basin, situated in southeastern Jilin is one of the easternmost Jehol Biota localities in China. Until now, the fossils here belonging to Jehol Biota have not yet been reported except for few fossils listed in geological survey reports. The fossil collections here are noteworthy in that they are the first fossil record documented from the Early Cretaceous Yingzuilazi Formation of the Baishan Basin, southeastern Jilin and the easternmost locality of Jehol Biota, China. This finding is important to explore the distribution, evolution and biodiversity of the Jehol Biota and even the Late Mesozoic terrestrial ecosystem, as well as for the division and correlation of the Late Mesozoic terrestrial strata.

The First Vertebrate Assemblage Dominated by Fishes and Turtles of the Jehol Biota in Jilin Province, NE China

Objective The Early Cretaceous sediments are well-exposed in southern Jilin Province,and yield abundant invertebrate and plant fossils,including the typical EosestheriaEphemeropsis trisetalis-Lycoptera（E-E-L）assemblage of the Jehol Biota（Shao Tiequan et al.,2017）.However,vertebrate fossils,especially tetrapods,are extremely rare and there is no formal documents on these fossils.Recently,a new fossil site dominated by fishes and turtles has been discovered in the middle part of the

Palaeoenvironments and Taphonomy of Bird Fossils(Early Cretaceous) from Jehol Biota in Western Liaoning,China

Jehol Biota in western Liaoning and northern Hebei has been a hot topic of global concern,a large number of exquisite fossils were found in Yixian group Sihetun,such as Sinosauropteryx,Protarchaeopteryx, Caudipteryx and Confuciusornis.Scientists consider the discovering of Sinosauropteryx discovered so far as the earliest ancestor of birds.According to the dates of root layer,we can see warm and humid,lakes

Vertebrate diversity of the Jehol Biota as compared with other lagersttten

In the last twenty years,the extraordinary discoveries of vertebrate fossils from the Jehol Biota not only have important impli-cations for studying the evolution of major Mesozoic vertebrate groups,their paleobiostratigraphy and paleoenvironmentology,but also provide critical evidence for understanding the biodiversity changes of the Early Cretaceous ecosystem.Currently,the Jehol Biota in a narrow sense(i.e.,distribution limited to western Liaoning,northern Hebei,and southeastern Inner Mongolia) comprises a vertebrate assemblage of at least 121 genera and 142 species.Among them are 13 genera and 15 species of mammals,33 genera and 39 species of birds,30 genera and 35 species of dinosaurs,17 genera and species of pterosaurs,5 genera and species of squamates,5 genera and 7 species of choristoderes,2 genera and species of turtles,8 genera and species of am-phibians,7 genera and 13 species of fishes as well as 1 genus and species of agnathan.All these known 121 genera are extinct forms,and only a small percentage of them(e.g.,agnathans,some fishes and amphibians) can be referred to extant families.The Jehol vertebrate diversity already exceeds that of the contemporaneous lagersttten such as Santana Fauna from Brazil and the Las Hoyas Fauna from Spain,and is nearly as great as that of the Jurassic Solnhofen Fauna and the Eocene Messel Fauna from Germany.Therefore,The Jehol Biota undoubtedly represents a world class lagerst?tte in terms of both fossil preservation and vertebrate diversity.The success of the Jehol vertebrate diversity had a complex biological,geological,and paleoenviron-mental background.Analysis of the habitat and diet of various vertebrate groups also indicates that the habitat and dietary dif-ferentiation had played a key role in the success of the taxonomic diversity of vertebrates of various ranks.Furthermore,the interactions among vertebrates,plants,and invertebrates as well as the competitions among various vertebrate groups and some key morphological innovations also contributed to the success of the Jehol vertebrate diversity.

Evolution of insect diversity in the Jehol Biota

Insects of the Jehol Biota,also known as the Jehol Entomofauna,can be divided into three phases,approximately corresponding to the early,middle,and late Jehol Biota.The early phase of the entomofauna is found in the Dabeigou Formation and its coeval horizons(ca.135-130 Ma).The middle phase is recorded from the lower-middle Yixian Formation(underlying the Jingangshan Bed) and its coeval strata(ca.130-122.5 Ma).The late phase is found in the lower Jiufotang Formation,the upper Yixian Formation(the Jingangshan and Huanghuashan beds) and their coeval horizons(ca.122.5-120 Ma).In major distribution areas of the Jehol Biota,the entomofauna changed greatly in species diversity with about 150 species in about 40 families and 11 orders in the early phase,a great increase up to about 500 species in about 100 families and 16 orders in the middle phase,and a decline to about 300 species in about 80 families and 14 orders in the late phase.The entomofauna can also be divided into four insect communities based on habitats or five insect groups based on feeding habits.Each community or group varied in species diversity in a similar trend to the whole entomofauna.However,it kept a comparatively stable position in the ecosystem.Of the four communities,the highest species diversity occurred in the forest community,followed by the aquatic,the soil,and the alpine communities.Of the five groups,the highest species diversity appeared in the phytophagous group,followed by the carnivorous,the parasitic,the saprophagous,and the heterophagous groups.

Study on the Jehol Biota:Recent advances and future prospects

The Jehol Biota is an Early Cretaceous terrestrial fossil assemblage of paramount significance,and its core distribution areas are western Liaoning,northern Hebei,and southeastern Inner Mongolia.Despite with a research history of more than 150 years,it started yielding important fossils until early 1990s,which include feathered dinosaurs,early birds,early mammals,flower-visiting insects,and early angiosperms.These discoveries have implications for understanding the origins and early evolution of several major organismal groups,as well as the origin and initial formation of modern terrestrial ecosystem.This review presents a brief introduction of the major discoveries,research history,and current understanding of this biota,and also provides future prospects for studying the Jehol Biota.

The Jehol Biota (Lower Cretaceous, China): new discoveries and future prospects

Continuing work on the paleontology and sedimentology of the Jehol Group(Lower Cretaceous,China)is yielding numerous new insights into the evolution of many Mesozoic plant and animal clades.Nevertheless,many questions remain unanswered regarding Jehol paleoenvironments,paleobiology and paleobiogeography.All of this information will be crucial in providing a detailed reconstruction of this extinct ecosystem.

Sinobaatar gen. nov.: First multituberculate from the Jehol Biota of Liaoning,Northeast China

A multituberculate skeleton from the Lower Cretaceous Yixian Formation at Dawangzhangzi, Lingyuan City, Liaoning Province, Northeast China, provides new morphological information for early multituberculates. The specimen is the holotype of Sinobaatar lingyuanensis gen. et sp. nov. It has a narrow skull that lacks the superorbital crest or postorbital process. The dental formula is 3·?·5·2/1·0·3·2. The dental morphology, especially that of cheek teeth, of S. lingyuanensis is similar to that of Eobaatar, which places it in the family Eobaataridae. The postcranial skeleton of Sinobaatar is similar to that of other multituberculates. As in Holotheria, Metatarsal V of Sinobaatar articulates only with the cuboid and has no contact with the calcaneus, which probably represents the primitive condition of multituberculates. Nine carpals of Sinobaatar resemble those of Zhang-heotherium, except the centrale being larger than the trape-zoid. The dental features of Sinobaatar show again that eo-baatarids are

A new species of Gobiconodon(Triconodonta, Mammalia) and its implication for the age of Jehol Biota

A new species of Gobiconodon is found from the Yixian Formation of western Liaoning, China. The new taxa, G. zofiae sp. nov., has a confluent opening for branches Ⅱ and Ⅲ of the trigeminal nerve on the anterior lamina of the petrosal. G. zofiae sp. nov. is similar to Repenomamus in having an ossified Meckels cartilage connecting the lower jaws and ear region. The new species, with enlarged I1/I1, posteriorly located infraorbital foramen and four mental foramina, distinctly differs from the other species of Gobiconodon. The new material indicates that Gobiconodon has four, not five, upper molariforms. The presence of Gobiconodon in Jehol Biota makes it possible to correlate Jehol Biota with faunas in eastern Asia and North America, and suggests the age of the Yixian Formation to be Early Cretaceous.

Morphological variation in fossil crayfish of the Jehol biota,Liaoning Province,China and its texonomic discrimination

Twelve morphological characteristics in 61 fossil crayfish specimens, which came from the Upper Jurassic Yixian Formation, are discussed respectively in the present paper. A study of these new and better preserved materials allows us to add to and revise the original description for Family Cricoidoscelosidae. In our collection, no modifications of the second pleopod of the males have yet been noted. This would be a crucial factor for the diagnosis of the family. Based on the presence of annulus ventralis in both Cricoidoscelosus and Palaeocambarus, they would appear to be very closely allied to those characteristics of the Family Cambaridae. In regard to the family Protastacidae, we seriously doubt it is actually crayfish, in light of the lack of any apomorphies identifiable within the Astacida, and their marine habitat.

An exceptionally well-preserved fossil Kalligrammatid from the Jehol Biota

A new species of Neuroptera, Sophogramma lii sp. nov. is described and illustrated in this paper. This new species is assigned to Sophogramma Ren of Kalligrammatidae, mainly based on its humeral recurrent veins, the basal cell present between posterior branch of media at base of wing, etc. The new species is distinguished from all other Sophogramma species on the difference of wing venation. This exceptionally well-preserved specimen is recovered from the Yixian Formation, Huangbanjigou, located near Beipiao City, in western Liaoning Province. The genus diagnosis has been emended based on new characters shown in this new species. Based on a summary of localities, distribution and geological ages of all genera and species of the Kalligrammatidae, we suggest that Kalligrammatids might have originated in Eastern Asia, especially in China. Function of the wing pigmentation is discussed briefly.

On the horizon of Protopteryx and the early vertebrate fossil assemblages of the Jehol Biota

Protopteryx, a monotypic fossil bird discovered from the Sichakou basin in Fengning, Hebei, is the most primitive enantiornithine currently known. The bird-bearing strata do not contain the index fossils of the Yixian Formation in western Liaoning; the fish and bird fossils have more primitive features than the related forms found in the Yixian Formation, and the conchostracans are those usually distributed in the Dabeigou and Dadianzi formations in northern Hebei. Besides, the Protopteryx-bearing strata underlie the deposits bearing the index fossils of the Yixian Formation in the neighboring basin. Thus, it could be confirmed that the horizon of Protopteryx should be lower than the Yixian Formation, and is approximately equivalent to the Dadianzi Formation in northern Hebei. This is the lowest horizon of the known fossil birds in China and Mesozoic enantiornithine birds in the world. Accompanying Protop- teryx, there are other birds, acipenseriform fishes, salamanders, and mammals, which compose the Peipiaosteus fengningensis-Protopteryx fengningensis assemblage. This new assemblage traces the vertebrate evolution history of the Jehol Biota back to 130.7 Ma before. It is suggested that the de- marcation of the Jehol Biota should be based on the large-scale tectonic-sedimentary cycles, and Peipiaosteus, instead of Lycoptera, could be taken as the vertebrate representative of the Jehol Biota.

华北早白垩世古地貌动态演变及热河生物群东迁

早白垩世期间,华北地区东北部分布着极其重要的生物群——热河生物群,其繁盛期对应着华北克拉通破坏峰值时期(125 Ma)。华北克拉通破坏导致的古地貌和古气候等环境变化,可能是引起热河生物群分布时空发生变迁的重要外部驱动因素之一。然而,目前缺少对华北地区早白垩世古地貌动态演变过程的定量描述。因此,本研究主要通过构建古土壤风化指标(PWI、CFX_(Na))、碳酸盐同位素等数据库,重建了华北地区晚侏罗世—早白垩世之交(145 Ma)的古地形;并结合磷灰石/锆石裂变径迹、剥蚀厚度恢复、海平面变化等数据,利用Badlands软件定量化动态模拟了华北地区早白垩世古地貌演变过程。模拟结果表明,早白垩世期间,受控于古太平洋板块俯冲后撤的影响,华北克拉通经历了由“东高西低”变为“西高东低”的地形翘变和破坏过程,并伴随着自西向东的断陷盆地的迁移;大规模火山喷发与断陷盆地的出现共同控制了热河生物群的向东迁移,热河生物群在燕山地区的山间盆地兴起。

Two New“Notostracans”,Chenops gen.nov.and Jeholops gen.nov. (Crustacea:Branchiopoda:?Notostraca) from the Yixian Formation,Northeastern China

The Early Cretaceous Jehol biota of northeastern China contains a diverse group of notostracans, including two genera, Chenops and Jeholops, described here. Chenops is characterized by a combination of an ovate carapace, narrow anal plate, equant distal endites and endopod on the anterior thoracic limbs. In addition to the new species, Chenops yixianensis, the genus also provisionally includes Prolepidurus oblongus Oleynikov, 1968. Jeholops, however, is monotypic, represented by the new species Jeholops hongi. It is characterized by a combination of kazacharthran and notostracan features unique to this taxon. Both new genera are provisionally placed in the taxon Notostraca. More detailed work exploring the morphology of exceptionally-preserved branchiopod crustaceans is needed. The difficulties in placing fossil notostracans into a phylogenetie framework are discussed.

冀北承德盆地早白垩世火山-沉积地层地质年代学研究:对热河生物群时空演化的制约

热河生物群是世界闻名的陆相生物化石宝库,保存了大量特异埋藏化石,为研究早白垩世脊椎动物、昆虫和植物的演化提供了绝佳的素材.依据古生物组合的不同,将其分为早、中、晚三期,分别赋存于河北丰宁花吉营组、辽西义县组和九佛堂组及其周边地区相当层位.河北承德—围场地区处于早-中期热河生物群分布地区的过渡地带,近年来不断的化石发现为研究华北克拉通破坏及其对陆地生态系统的影响提供了关键证据.但由于缺乏准确的年龄约束,对于含化石层位的准确时代及其与邻区地层对比存在较大争议.本文利用来自于河北北部承德盆地袁家庄剖面的3个安山岩样品的锆石,进行化学熔蚀-离子探针(CA-SIMS)锆石U-Pb定年,获得年龄为129.6~128.7 Ma.结合前人发表的磁性地层学结果建立了新的磁性地层学对比方案和新的综合年代框架,揭示了该剖面火山-沉积序列记录了古地磁极性序列M8n-M7n,进一步证明了袁家庄剖面的陆相火山-沉积层序属于欧特里夫晚期.结合区域内前人年代学结果,将该区域热河生物群化石层时代限定为130~127 Ma.年代地层学对比结果显示,承德盆地早白垩世火山-沉积序列与滦平盆地大店子组和森吉图—四岔口盆地花吉营组上部时代相当,明显老于辽西义县组时代,揭示了华北克拉通北缘早白垩世陆相地层的自西向东逐渐年轻的特征.

伤齿龙类在内蒙古宁城盆地热河生物群的新发现

伤齿龙类是种小—中型的兽脚类恐龙,主要发现于亚洲和北美的白垩纪地层。传统认为伤齿龙科与驰龙科互为姊妹群,共同组成恐爪龙类,构成了与鸟类最近的个演化支系,其系统古生物学研究,对探讨鸟类起源具有重要意义。与驰龙科相比,伤齿龙科的化石材料较少,研究程度较低。我国的伤齿龙类化石迄今共发现12属12种;其中热河生物群共发现7属7种,均属于伤齿龙类早期分异类型。2014年,在内蒙古赤峰市宁城县附近的野外考察中,我们发现了处早白垩世恐龙化石集群.