Palaeoenvironmental analysis of Cenomanian-Turonian dinocyst assemblages from the Castilian Platform (Northern-Central Spain)     

Daniel Peyrot  Fernando Barroso-Barcenilla  Eduardo BarrónMaría José Comas-Rengifo 《Cretaceous Research》2011,32(4):504-526

The palynological assemblages from three Cenomanian-Turonian sections from the Castilian Platform are described. The 49 levels analysed yielded a well-diversified palynological content including dinoflagellate cysts, acritarchs, prasinophytes and miospores. The comparison of the terrestrial and marine assemblages from these three sections reveals significant differences that are mainly related to their relative palaeogeographical locations. The quantitative study performed on dinocyst assemblages suggests an association interpreted as inner neritic including Xenascus ceratioides, Cribroperidinium exilicristatum, Canningia reticulata and Kallosphaeridium? ringnesiorum. On the contrary, the group inferred to show outer neritic preferences is integrated by Palaeohystrichophora infusorioides, Spiniferites spp., Odontochitina spp., Trichodinium castanea and Impletosphaeridium polytrichum. In the Castilian Platform, the Cenomanian-Turonian Boundary Event (CTBE) may be manifested by a higher proportion of Cyclonephelium spp. in the distal dinocyst assemblages.  相似文献   

Overabundance of piscivorous dinosaurs (Theropoda: Spinosauridae) in the mid-Cretaceous of North Africa: The Algerian dilemma     

《Cretaceous Research》2015

The informally called ‘Continental intercalaire’ is a series of continental and brackish deposits that outcrops in several regions of North Africa. The age of the series is not well-constrained, but its upper part, visible in the ‘Kem Kem beds’ in Morocco and in Bahariya in Egypt, is regarded as early Cenomanian in age. Spinosaurid remains are an important component of this series, but records of this dinosaur are surprisingly rare in Algerian localities of the ‘Continental intercalaire’. Here, we describe a vertebrate assemblage from two localities, Kénadsa and Menaguir, situated in the Guir basin, Western Algeria. The assemblage comprises hybodont sharks, sarcopterygian fishes, ray-finned fishes, turtles, crocodiles and dinosaurs. Among the latter, only teeth of theropods have been recovered and 94% belong to Spinosaurus. The assemblage is taxonomically very similar to the Moroccan and Egyptian assemblages mentioned above. This study: 1) suggests a likely early Cenomanian age for the Guir basin deposits containing the assemblage; 2) provides a new evidence of the homogeneity of the early Cenomanian vertebrate fauna throughout North Africa; and 3) confirms the overabundance of theropod dinosaurs, especially spinosaurs, in the assemblage showing a possible shortcut in the vertebrate food chain. The northern most locality, Menaguir, shows sedimentological and ichnological evidence of marine influences indicating that the palaeoenvironment shows spatial heterogeneities.  相似文献   

西藏特提斯喜马拉雅白垩纪中期Cenomanian-Turonian期碳同位素偏移   总被引：5，自引：0，他引：5  

李祥辉  王成善  成鑫荣  崔杰  胡修棉 《地球科学》2005,30(3):317-327

过去大量关于白垩纪中期Cenomanian-Turonian晴期的古海洋及其界线时期缺氧事件研究的高分辨率碳氧同位素的实际材料绝大多数都来自深海钻探(DSDlP)、大洋钻探(0DP)和欧美的一些较深水盆地．通过对西藏南部地区(位处特提斯洋东南)同一层位高分辨率碳同位素分析,目的在于为Cenomanian-Turonian古海洋及全球事件的碳同位素响应提供西藏地区的对比材料,并试图就浅海相的变化情况进行探讨．西藏定日和岗巴地区的高分辨率碳同位素分析结果显示．δ^13C值在Cenomanian中晚期稳定,Cenomanian-Turonian界线时期快速高幅正偏,Turonian期持续负偏,这种长期变化趋势在特提斯甚至全球可以对比．深入研究还发现,Turonian中后期存在2个较大幅度的负偏凹陷区,与来自欧洲的相关资料在偏移时间和幅度方面惊人相似．对比分析表明,岗巴地区δ^13C值长期变化和短期波动幅度及步调与定日及全球其他地区存在一定差别,幅度差异可能与样品制备和成岩改造有关,步调不一致则可能受生物地层定位的影响．研究区近海一半远洋环境Cenomanian-Turonian界线时期未出现典型富有机质黑色页岩,说明δ^13C值极度正偏与黑色页岩的出现并非一对应．  相似文献   

高分辨率碳氧同位素应用及西藏岗巴地区白垩纪中期Cenomanian-Turonian期碳同位素偏移   总被引：2，自引：0，他引：2  

李祥辉  王成善  崔杰 《地学前缘》2005,12(2):171-177

介绍了高分辨率碳氧同位素的应用成果;指出半远洋、远洋碳酸盐全岩高分辨率碳同位素高值正偏可作为甄别大洋缺氧事件的指示剂和分析古气候变化的指针,碳同位素偏移型式可为长期海平面变化和短期海平面波动提供参照对比的依据。西藏南部岗巴地区的高分辨率偏移曲线显示,碳同位素Cenomanian Tu ronian界线时期的正偏幅度达2.90‰,Turonian期长期持续负偏,并在M. sigali带中、下部呈现两个负偏凹陷区。这表明,该区白垩纪中期Cenomanian Turonian期存在可以在特提斯甚至全球类比的碳同位素变化趋势,表现为Cenomanian Turonian界线时期的缺氧事件、Turonian期的长期海平面下降趋势和Turonian晚期短暂气候变冷的响应。  相似文献   

First boganiine beetle in mid-Cretaceous amber from northern Myanmar (Coleoptera: Boganiidae)     

Chenyang Cai  Diying Huang 《Proceedings of the Geologists' Association. Geologists' Association》2019,130(1):81-86

Cretoboganium gei gen. et sp. nov., a new amber inclusion of the cucujoid family Boganiidae is described and figured based on a well-preserved adult from the mid-Cretaceous Burmese amber (Hukawng Valley, northern Myanmar), some 99 million years ago. Based on the presence of a pair of pronotal callosities, Cretoboganium can be firmly placed in the extant subfamily Boganiinae, a small group currently comprising two small austral genera. Our discovery represents the first fossil record for Boganiinae. It also demonstrates another example that an apparently austral group may have its sister group occurred in today’s northern hemisphere. Together with the other fossil boganiid known from the Middle Jurassic of China, the finding suggests that Boganiidae is an ancient and relict group. Moreover, the present biogeographic distribution of Boganiinae is indicative of an earlier origin of this subfamily, which likely originated before the breakup of the Gondwanan supercontinent.  相似文献   

The first aeshnoid dragonfly (Odonata: Anisoptera: Telephlebiidae) from mid-Cretaceous Burmese amber     

《Cretaceous Research》2017

A new true dragonfly, Cretaeshna lini gen. et sp. nov., is described based on a forewing from mid-Cretaceous Burmese amber. Cretaeshna is probably a member of Telephlebiidae: Telephlebiinae, but differs from the latter in having a weakly-defined IR1 and a short pterostigma. Cretaeshna lini is the first aeshnid dragonfly to be found as an amber inclusion and the third Cretaceous true dragonfly recorded in amber. Our find augments the diversity of Mesozoic true dragonflies, and enhances our understanding of the palaeogeographic distribution of aeshnid dragonflies.  相似文献   

A new genus and species of pygidicranid earwigs from the Upper Cretaceous of southern Asia (Dermaptera: Pygidicranidae)     

《Cretaceous Research》2017

A third genus and species of fossil pygidicranid earwigs from Burmese amber is described and figured as Stonychopygia leptocerca Engel, Huang, Thomas, and Cai, gen. et sp. nov. (type species of Stonychopygia Engel and Huang, gen. nov.; Stonychopygiinae Engel and Huang, subfam. nov.). Stonychopygia have features similar to the subfamily Echinosomatinae such as the combination of shorter, subequal second and third flagellomeres and femora that are neither compressed or keeled. However, the new fossil species differs from echinosomatines in many details, particularly the slender form, head longer than wide, slender scape, slender and elongate forceps, and absence of stout, short bristles over the integument. The new fossil is compared with its contemporaneous and modern relatives, and comments are provided regarding the classification of Pygidicranoidea, with the genus Haplodiplatys Hincks removed from Diplatyidae to Haplodiplatyidae Engel, fam. nov.  相似文献   

Redescription of the elasmosaurid plesiosaurian Libonectes atlasense from the Upper Cretaceous of Morocco     

《Cretaceous Research》2017

The holotype of Libonectes atlasense is an almost complete skeleton from Upper Cretaceous (mid-Turonian) rocks of the Goulmima area in eastern Morocco. Initial assessment of this specimen in 2005 proposed generic referral based on stratigraphical contemporaneity with Libonectes morgani from the Cenomanian–Turonian of Texas, U.S.A. Nevertheless, relative differences in the profile of the premaxillary-maxillary tooth row, position of the external bony nasal opening, number of teeth and rostrad inclination of the mandibular symphysis, proportions of the axial neural arch, and number of cervical and pectoral vertebrae were used to distinguish between these species. As part of an on-going comparative appraisal of elasmosaurid plesiosaurian osteo-anatomy, we re-examined the type and formally referred material of both L. atlasense and L. morgani in order to establish species validity, as well as compile a comparative atlas for use in future works. Our inspections revealed that these reportedly distinct species-level fossils are in fact virtually indistinguishable in gross morphology. Indeed, the only substantial difference occurs in relative prominence of the midline keel along the mandibular symphysis, which might be explained by intraspecific variation. Furthermore, our observations permit an amendment to the published generic diagnosis of Libonectes with the confirmation of important states such as the likely presence of a pectoral bar, distocaudad expansion of the humerus, and an epipodial foramen. In addition, novel features include a prominent ‘prong-like’ ventral midline process on the coracoids, and the development of a median pelvic bar that encloses a central fenestration. The composite remains of L. morgani thus constitute one of the most complete elasmosaurid skeletal hypodigms documented worldwide, and evidence a trans-Atlantic distribution for this apparently dispersive species during the early–Late Cretaceous.  相似文献   

Clidicostigus gen. nov., the first Mesozoic genus of Mastigini (Coleoptera: Staphylinidae: Scydmaeninae) from Cenomanian Burmese amber     

《Cretaceous Research》2017

The Mastigitae is a small supertribe of ant-like stone beetles that currently includes nine extant and five extinct genera. Extinct taxa are known within tribes Clidicini and Mastigini; the latter with one genus discovered in Baltic amber. For the first time, a Mesozoic genus of the tribe Mastigini is described, Clidicostigus arachnipes Jałoszyński, Brunke and Bai, gen. et sp. nov., from Cenomanian Burmese amber. The new taxon shares an enlarged and spiny scape and pedicel with its extant relatives but has deep elytral grooves and a strongly elongate and asymmetrical maxillary palpomere IV; the beetle has also enormously elongate maxillary palps and legs. The elongation of appendages in combination with only moderately large eyes is postulated to have evolved as an adaptation to running quickly, with tactile and chemical senses predominating over sight. The mode of life of Clidicostigus might have been similar to that of extant Mastigini, especially of particularly slender South African species that run on the ground and climb bushes and trees in search of prey.  相似文献   

A new extinct genus of Glandulariini with two species from Upper Cretaceous Burmese amber (Coleoptera: Staphylinidae: Scydmaeninae)     

《Cretaceous Research》2017

The Glandulariini (=Cyrtoscydmini) is today the largest, most species-rich and most diverse tribe of Scydmaeninae comprising over 70% of the extant species of this subfamily. Named genera and species of Glandulariini are known mostly from Miocene to Eocene ambers, with only one, recently described Mesozoic taxon. Here we report the second genus of Glandulariini from Upper Cretaceous Burmese amber, Cenomaniola Jałoszyński and Yamamoto, gen. nov., with two species, C. carinata Jałoszyński and Yamamoto, sp. nov. and C. macrophthalma Jałoszyński and Yamamoto, sp. nov. Cenomaniola shows the general body plan typical of the ‘Euconnus complex’ within Glandulariini, with thick bristles on the sides of head and pronotum, a character conserved for nearly a hundred million years. With the previous discovery of Scydmobisetia Jałoszyński and Yamamoto, two major body forms typical of the extant Glandulariini are already proved to have differentiated in or before the Late Cretaceous. This demonstrates early origins and a long conservation of ‘Euconnus-like’ and ‘Sciacharis/Horaeomorphus-like’ body plan in the currently largest group among Scydmaeninae.  相似文献