内蒙古鄂托克早白垩世恐龙足迹化石8号点风化机理研究

内蒙古鄂托克旗查布地区是罕见的恐龙足迹等遗迹化石分布区,分布着大量白垩纪恐龙足迹化石。这些足迹化石在野外遭受着不同程度的风化破坏,为此在足迹密集的核心区8号点建立了野外地质遗迹博物馆保护原址。跟踪观察后发现室内足迹化石的风化程度相较于露天保存更加严重,尤其在馆内靠近四周围墙的区域,足痕表面酥粉破碎,有的足迹甚至完全消失。为研究8号点足迹化石的风化原因,本文对8号点馆内外赋存于同一层位的岩石进行取样,使用偏光显微镜(PM)、X射线衍射(XRD)、压汞(MIP)、离子色谱(IC)、拉曼光谱(Raman)、傅里叶变换红外光谱(FTIR)以及扫描电子显微镜能谱(SEM-EDS)等方法进行分析,结果发现室内岩石的孔隙率更高,孔径更大,可溶盐含量是室外上层的2倍,室外下层的约11倍,种类以NaCl和Na₂SO₄为主。模拟实验显示,相比冻融作用,Na₂SO₄更具有破坏性。由此认为导致鄂托克遗迹博物馆内恐龙足迹化石风化的机理是由地下水和降雨形成的地表水共同作用的结果,尤以Na₂SO_4...     

Parataxonomy and palaeobiogeographic significance of dinosaur eggshell fragments from the Upper Cretaceous strata of the Cauvery Basin,South India

Abstract

In the past, fossilised dinosaur eggshells have been extensively documented from the Upper Cretaceous Lameta Formation of Central India and as many as nine oospecies are known at present from this formation. Compared to this, only one dinosaur oospecies has been described from the Cretaceous succession of the Cauvery Basin. However, the first fossil egg from India, identified as a chelonian egg, was documented from the Aptian – Albian Karai Formation of the Cauvery Basin in 1957. Following this, a solitary titanosaurid dinosaur egg was described from the Upper Cretaceous (Lower Maastrichtian) Kallankuruchhi Formation, Cauvery Basin in 1996. More recently, we have recovered isolated eggshell fragments from the marine part of the Upper Cretaceous (Late Maastrichtian) Kallamedu Formation. Based on eggshell morphology, microstructure and ultrastructure, these eggshell fragments are assigned to the oospecies Fusioolithus baghensis. The new find from the Cauvery Basin is important from palaeobiogeographic point of view as the oofamily Fusioolithidae is found in the Upper Cretaceous strata of India, France, Argentina and Morocco. Based on the common occurrence of similar oospecies in South America, Africa, Europe and India, a Late Cretaceous palaeobiogeographic connection between India and South America as well as Europe via Africa is suggested.     

纵纹腹小、鵰及长耳的卵壳超微结构研究（形目：鸱科）

本文首次报道纵纹腹小、、长耳卵壳的气孔、木栅层、锥体层、乳锥体、壳膜、基底帽等结构的扫描电镜观察,并对不同种类进行分析,初步探讨了它们的分类价值和生态意义。     

山东莱阳晚白垩世恐龙与恐龙蛋研究历史和新进展

简要回顾了莱阳恐龙和恐龙蛋化石群的研究历史和以杨钟健为代表的老一代地质古生物学者对莱阳恐龙和恐龙蛋研究发现的杰出贡献,并介绍了莱阳恐龙和恐龙蛋的最新发现和若干研究进展.在近年来对莱阳周边地层进行的大规模考察中,发现了一系列发育在平原上的恐龙峡谷群,以及其中蕴含的十几个恐龙和恐龙蛋新地点和新层位.2010年开始,在对莱阳金岗口村附近的2个化石地点的发掘中,发现了以鸭嘴龙科为主的大量脊椎动物化石和蛋化石,包括一类新的栉龙亚科成员,一些大型兽脚类恐龙化石,以及一新的龟鳖类蛋化石等.2号地点化石富集层具有典型的泥石流沉积特征和骨骼埋藏特征.对棘鼻青岛龙的特殊头饰进行了CT扫描和三维重建,发现其头饰是实心结构,但其他骨骼特征证明棘鼻青岛龙属于具有头饰的赖氏龙亚科是确定无疑的,所以目前发现的头饰应不是其真实状态或根本不属于其头部骨骼.此外,对谭氏龙1属3种的重新观察研究得出以下结论:中国谭氏龙和金刚口谭氏龙应是有效属种,但部分骨骼还有疑问,还需要进一步研究,而莱阳谭氏龙为无效属种.     

A description of Megalosaurus bucklandii (Dinosauria: Theropoda) from the Bathonian of the UK and the relationships of Middle Jurassic theropods

Megalosaurus bucklandii (Dinosauria: Theropoda), the oldest named dinosaur taxon, from the Bathonian (Middle Jurassic) of England, is a valid taxon diagnosed by a unique character combination of the lectotype dentary. Abundant referred material is described and several autapomorphies are identified: ventral surfaces of first and third to fifth sacral centra evenly rounded, ventral surface of second sacral centrum bearing longitudinal, angular ridge; dorsally directed flange around midheight on the scapular blade; an array of posterodorsally inclined grooves on the lateral surface of the median iliac ridge; anteroposteriorly thick ischial apron with an almost flat medial surface; and complementary groove and ridge structures on the articular surfaces between metatarsals II and III. A new phylogenetic analysis focuses on basal tetanurans and includes 41 taxa, six of which have never been included in a cladistic analysis, and 213 characters, 29 of which are new. This is the first phylogenetic analysis to focus on basal tetanuran relationships, and it reveals several new results. Megalosauroidea (= Spinosauroidea) includes two clades, basal to the traditional content of Megalosauridae + Spinosauridae. These comprise Xuanhanosaurus, Marshosaurus, Condorraptor + Piatnitzkysaurus and Chuandongocoelurus + Monolophosaurus. Almost all large‐bodied Middle Jurassic theropods are megalosauroids, but Poekilopleuron is an allosauroid. Megalosauroids show geographical differentiation among clades, indicating the development of endemic theropod faunas across Pangaea during the Middle Jurassic. Notably, megalosaurids are not known from outside of Europe during this epoch. Megalosauroids are less diverse and abundant during the Late Jurassic, when most theropods are neotetanurans and allosauroids dominate the large‐bodied predator niche. This indicates faunal turnover between the Middle and Late Jurassic. © 2009 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 158 , 882–935.     

Improved hatching for in vitro quail embryo culture using surrogate eggshell and artificial vessel

The establishment of avian embryonic culture is important both for the analysis of the developmental process and the establishment of transgenic chickens that produce useful biological materials in eggs. However, the hatchability of cultured embryos has been ∼50%. We identified that the low rate of hatchability of cultured embryos was caused by limited oxygen and calcium availability. In quail embryo culture using chicken eggshell as a culture vessel,viability in the middle stage of culture was improved and 30% of embryos were hatched by oxygen enrichment. Furthermore, hatchability increased to 80% by supplementation with calcium lactate in addition to oxygen aeration. In the present study, a fully artificial vessel for quail embryo culture was designed using a gas-permeable Teflon membrane. By the addition of fine eggshell powder and calcium lactate, quail embryos grew and developed normally, and 43% of embryos hatched. Although the hatchability was lower than that of cultures using a surrogate eggshell, we achieved in hatching an avian embryo using a fully artificial vessel.     

The N-terminal prodomain of sV23 is essential for the assembly of a functional vitelline membrane network in Drosophila

The vitelline membrane is a specialized extracellular matrix that surrounds and protects the oocyte. Recent studies indicate that it also serves as a storage site for embryonic pattern determinants. sV23, a major vitelline membrane protein, is essential for the morphogenesis of the vitelline membrane as sV23 protein null mutants lay flaccid, infertile eggs. By analyzing a series of sV23 mutant transgenes in the sV23 protein null genetic background, we have shown that sV23 is secreted as a proprotein in functional excess and that C- and N-terminal prodomains are removed successively, following its deposition in the extracellular space. Although a target site for subtilisin-like convertases is essential for N-terminal processing, N-terminal processing is not necessary for the assembly of a functional vitelline membrane layer. While C-terminal truncations were tolerated, the removal of N-terminal sequences lead to the production of flaccid, infertile eggs with a soluble, rather than insoluble, vitelline membrane network. We propose that the hydrophobic N-terminal prodomain plays an early and essential role in aligning molecules within the vitelline membrane network, much like hydrophobic domains within elastin drive the assembly and alignment of molecules within elastin-based extracellular matrices.     

First Early Jurassic Ornithischian and theropod footprint assemblage and a new ichnotaxon Shenmuichnus wangi ichnosp. nov. from Yunnan Province,southwestern China

The new ichnospecies, Shenmuichnus wangi ichnosp. nov., is the first evidence for the presence of large ornithischians in the Early Jurassic of Yunnan Province, whereas the known skeletal record documents small species only. Until now Shenmuichnus was known from a single locality in Shaanxi Province by the ichnospecies Shenmuichnus youngteilhardorum. Compared with the latter, Shenmuichnus wangi is larger and shows a different trackway configuration, particularly in the relative position of manus and pes imprints. Palecologically, the occurrence of Shenmuichnus wangi in a red bed facies indicates the preference of distinctive environments of trackmakers of both ichnospecies, questioning former hypotheses of exclusivity of ornithischians in more humid climates. By abundance both skeletons and footprints of ornithischians suggest their role as a minor component in Early Jurassic saurischian dominated dinosaur faunas in this region.     

Salmonella enterica isolates from layer farm environments are able to form biofilm on eggshell surfaces

This study examined the eggshell biofilm forming ability of Salmonella enterica isolates recovered from egg farms. Multicellular behaviour and biofilm production were examined at 22 and 37°C by Congo red morphology and the crystal violet staining assay. The results indicated that the biofilm forming behaviour of Salmonella isolates was dependent on temperature and associated with serovars. Significantly greater biofilm production was observed at 22°C compared with 37°C. The number of viable biofilm cells attached to eggshells after incubation for 48 h at 22°C was significantly influenced by serovar. Scanning electron microscopic examination revealed firm attachment of bacterial cells to the eggshell surface. The relative expression of csgD and adrA gene was significantly higher in eggshell biofilm cells of S. Mbandaka and S. Oranienburg. These findings demonstrate that Salmonella isolates are capable of forming biofilm on the eggshell surface and that this behaviour is influenced by temperature and serovar.     

Partial incubation during egg laying reduces eggshell microbial loads in a temperate‐breeding passerine

Incubation prior to clutch completion may be adaptive if it maintains egg viability by inhibiting eggshell microbial growth, thus reducing the likelihood that the embryo becomes infected. To test this hypothesis, we examined the effect of partial incubation during egg laying on eggshell microbial loads in eastern bluebirds Sialia sialis breeding at a temperate‐zone site. We sampled eggshell microbes prior to and following four days of exposure to either partial incubation during the laying period or ambient environmental conditions without incubation (experimental eggs). Microbial colony counts declined significantly for eggs left in the nest during the laying period but did not vary significantly for eggs exposed to ambient conditions. Initial microbial loads were more similar to those previously reported from tropical than temperate environments, and microbes from potentially pathogenic groups were detected on 88% of first‐laid eggs on the day of laying. Egg viability was maintained when eggs were held indoors for four days without incubation but declined sharply thereafter. Our results suggest that partial incubation during egg laying may enhance egg viability in eastern bluebirds by reducing eggshell microbial loads; these effects appear stronger than those usually reported from the temperate zone.