A New Angiosperm Genus from the Lower Cretaceous Yixian Formation, Western Liaoning, China

The abundant fossils of early angiosperms found in the Yixian Formation (125 Ma, Early Cretaceous) have demonstrated unexpectedly high diversity and various reproductive strategies, and thus have shed new light on early angiosperm evolution. Here, using light microscope and scanning electron microscope, we document several fructifications of Baicarpus gen. nov. from Liaoning province, China. Each fructification of the new taxon includes several apocarpous carpels/fruits attached in an urn-formed gynobase. Each fruit/carpel has a persistent straight style and an ovary enclosing a single seed. These fossil plants demonstrate a new floral organization and thus enhance our understanding of the diversity of angiosperms in the Yixian Formation. Together with previously reported ones, this fossil angiosperm suggests an origin time for angiosperms earlier than widely accepted.     

A Novel Angiosperm from the Early Cretaceous and Its Implications for Carpel‐Deriving

The Yixian Formation (Lower Cretaceous) of China is famous for its fossils of early angiosperms, and these fossils have shed otherwise unavailable light on the evolution of angiosperms. The seeds in Archaefructus and Nothodichocarpum are inserted along the dorsal of the fruits while those in Sinocarpus are along the ventral of the fruits, suggesting different Bau‐plans and pathways deriving the carpels in these plants of the Early Cretaceous. Adding further fossil evidence, here we report a novel fossil angiosperm, Neofructus lingyuanensis gen. et sp. nov, with its seeds inserted on both ventral and dorsal sides of the fruits documented through light microscopic and SEM observations, suggesting a novel way forming gynoecium in the Yixian Formation. These fossil angiosperms indicate that angiosperm gynoecia in the Yixian Formation (the Barremian to Aptian) are derived in obviously different ways, implying an evolutionary scenario for angiosperms quite different from formerly assumed.     

The Earliest Ascidiate Carpel and Its Implications for Angiosperm Evolution

According to the classic doctrine of angiosperm evolution, the archetype carpel in angiosperms is of plicate form. However, this concept is facing increasing challenges from the systematics based on molecular data, which now takes ascidiate carpel as ancestral. This reorientation in evolutionary thinking cannot be fully achieved unless there is supporting fossil evidence. Here a fruit, named Liaoningfructus, is reported from the famous Yixian Formation (Early Cretaceous, 125 Ma), which yielded several pioneer angiosperms in the past decades. The configuration of the fruit suggests that the carpel giving rise to the fruit is most likely ascidiate, favoring the above reorientation. There are two seeds in the fruit, and at least one of them is served by a vascular bundle arising from the bottom of the fruit, implying a basal placentation in the former carpel, which again is different from the classic thinking. This discovery not only enhances the diversity of angiosperms in the Yixian Formation, but also accelerates the on-going switching of thinking on angiosperm evolution     

Fossil coniferous wood from the Early Cretaceous Jehol Biota in western Liaoning,NE China: New material and palaeoclimate implications

The Early Cretaceous Jehol Biota, one of the most important Mesozoic lagerstätten in East Asia, is especially well-known for occurrences of fossil feathered dinosaurs and early angiosperms. However, the terrestrial biodiversity, especially the fossil wood record, is poorly known. In this study, several structurally preserved coniferous wood specimens from the Lower Cretaceous Yixian Formation are investigated, based on collections from the Heichengzi Basin in Beipiao of western Liaoning, Northeast China. Four species referred to four genera of fossil wood are described, including Taxodioxylon heichengziense sp. nov., Thujoxylon beipiaoense sp. nov., Sciadopityoxylon liaoningense Ding and Protocedroxylon shengjinbeigouense sp. nov. These new records enlarge the fossil wood diversity of the Yixian Formation up to 10 species in 9 genera, and provide further insights into the forest vegetation composition of the Early Cretaceous Jehol Biota. Systematic analysis of the floral constitution indicates that the petrified forests of the Yixian Formation are dominated by conifers, represented by Araucariaceae, Podocarpaceae, Sciadopityaceae, Pinaceae and Cupressaceae in the western Liaoning region. Palaeoclimatical analysis of the fossil wood assemblage implies that the western Liaoning region was dominated by a cool temperate, wet and seasonal climate with variable interannual water supply in the western Liaoning region during the Early Cretaceous.     

Is Darwin's ‘Abominable Mystery’ still a mystery today?

Darwin described the Cretaceous diversification and subsequent rapid rise of flowering plants (angiosperms) as an “abominable mystery”: how could they have achieved worldwide ecological dominance by early Paleogene times when the oldest angiosperm fossils are only Cretaceous in age? However, recent phylogenetic and palaeobiogeographical analyses have suggested a much earlier, perhaps Triassic origin for the stem angiosperms. We suggest that the fossil record is accurately reflecting the rapid diversification of the crown angiosperms that molecular data suggests occurred in Cretaceous–early Palaeogene times, and which coincides with similar explosive diversifications that occurred in other parts of the terrestrial biota including insects, birds and mammals. Early, stem angiosperms are poorly represented in the fossil record for a combination of taphonomic and ecological reasons. We conclude that the reported evidence shows that the Darwin's “mystery” is in fact no mystery and confirms that it merely requires an appropriate reading of the fossil record.     

辽西首次发现保存毛发和软件的中生代哺乳动物化石

中国辽西地区素以产出丰富多彩的中生代热河生物群闻名于世。特别是近几年来，该区大量长羽毛的恐龙、原始鸟类、原始哺乳类和被子植物化石的发现更加引起了国际科学界的极大关注。1997年秋，作者在辽宁北票四合屯地区发现了一块完整的保存有毛发和软体印痕的对齿兽类哺乳动物化石。身体保存有手发和软体印痕的中生代哺乳动物化石在世界上也是罕见的。对对于研究对齿兽形态结构、生物习性、系统关系等方面均具有重要意义。     

中国吉林大拉子组的时代探讨

大拉子组是我国东北地区早白垩世的典型层位,但该组的具体地质年代一直存在不同的看法。根据最近发现的植物化石材料,通过对大拉子组被子植物优势属的地质分布以及与国内外被子植物群的对比研究,发现大拉子组与北美Potomac带B中部的被子植物群较为相似,结合孢粉、昆虫、叶肢介、介形虫及鱼化石等其他生物化石证据,认为吉林大拉子组的地质时代很可能为阿尔必中期或晚期。     

辽西早白垩世离龙类地理地史分布及其演化

离龙类是一在形态和生态适应上高度特化的水生—半水生爬行动物双孔亚纲的灭绝支系。离龙目的地理分布局限于北半球,地史分布从侏罗纪一直延续到中新世。辽西是中国最为重要的离龙类化石产地,化石点主要分布于凌源、义县、朝阳和建昌4个地区,尤其以义县地区化石点的分布最为密集。目前辽西已经发现的离龙类包括3科4属5种,其中潜龙和满洲鳄2属的化石仅发现于义县组,而伊克昭龙与戏水龙2属的化石则仅见于九佛堂组。化石证据表明,白垩纪离龙类在辽西范围内的延展分布呈现一个自西向东、由南向北的地理地史演化过程。化石证据也表明辽西的离龙类在较短的时期和较窄的地域范围内经历了一个快速分异演化的过程。长颈潜龙类和短吻满洲鳄类在辽西同时首现于凌源义县组大新房子层,并先后灭绝于义县组的大康堡层和金刚山层。潜龙类最后出现的大康堡层的火山凝灰岩层密集保存了数以千计的潜龙类个体,可能代表该类群于早白垩世发生了与火山喷发活动紧密相关的集群灭绝事件。而后,短吻戏水龙和长吻伊克昭龙同时首现于九佛堂组第2段,并于该组第3段沉积时期内灭绝。整个辽西地域内的离龙类的分布从126～120Ma,在经历了大约6Ma的快速分异演化之后,均于早白垩世阿普第期灭绝。     

A Whole Plant Herbaceous Angiosperm from the Middle Jurassic of China

In contrast to woody habit with secondary growth, truthful herbaceous habit lacking secondary growth is restricted to angiosperms among seed plants. Although angiosperms might have occurred as early as in the Triassic and herbaceous habit theoretically may have been well adopted by pioneer angiosperms, pre-Cretaceous herbs are missing hitherto, leaving the origin of herbs and evolution of herbaceous angiosperms mysterious. Here we report Juraherba bodae gen. et sp. nov, a whole plant herbaceous angiosperm, from the Middle Jurassic (>164 Ma) at Daohugou Village, Inner Mongolia, China, a fossil Lagerst?tten that is worldwide famous for various fossil finds. The angiospermous affinity of Juraherba is ensured by its enclosed ovules/seeds. The plant is small but complete, with physically connected hairy root, stem, leaves, and fructifications. The Middle Jurassic age recommends Juraherba as the earliest record of herbaceous seed plants, demanding a refresh look at the evolutionary history of angiosperms.     

Early Cretaceous Archaefructus eoflora sp. nov. with Bisexual Flowers from Beipiao, Western Liaoning, China

Recently, whether Archaefructus has bisexual multi-parted flowers or just inflorescences of unisexual flowers, and whether it is ancestral to all angiosperms or a derived eudicot have been debated. Here, from the same Yixian Formation, NE China, we report a new Archaefructus species, A. eoflora sp. nov., with the generic characteristics of dissected leaves and bisexual reproductive axes. It is entirely preserved with roots, rhizome, shoots and protogynous reproductive organs at different developmental stages. Its lateral and main fertile shoots form a pseudo-indeterminate pattern, while the reproductive branches on the main shoot form a cymose inflorescence. Subtended by 1-2 bract-like leaves, the section of stamen clusters changes into a much shorter section of carpels that have one row of orthotropous ovules. Significantly, one cluster bearing two carpels and one stamen between the two sections demonstrates a true bisexual flower, an important step of the origin of floral bisexuality, and the homology     

A New Symmetrodont Mammal with Fur Impressions from the Mesozoic of China

Western Liaoning of northeastern China is world-renowned for the Mesozoic Jehol biota, especially for yielding many feathered dinosaurs, primitive birds, mammals and fossil angiosperm. This paper describes a complete specimen of a symmetrodont mammal with well-preserved hairs and soft tissue from the basal part of the Yixian Formation in the Sihetun area, Beipiao, western Liaoning. It is significant for understanding the morphology, osteology, phylogeny and life habits of Mesozoic symmetrodont mammals.     

辽西义县下白垩统九佛堂组木化石的发现

首次发现产自辽西义县皮家沟下白垩统九佛堂组保存有解剖构造的木化石,利用木化石切片法对木化石解剖特征进行研究。当前木化石均为硅化保存,其中一块标本保存有髓、初生木质部、次生木质部等解剖构造。其髓部主要由薄壁细胞构成,初生木质部为内始式,次生木质部为Protophyllocladoxylon型。部分木化石标本表面密布大小不一的孔洞,推测为昆虫幼虫的觅食痕迹。此外,木化石产出层位还发现有大量丝碳化石,表明义县地区早白垩世九佛堂组沉积时期存在野火事件,而频发的火山喷发活动可能是野火事件的诱因。     

The first fossil species of subfamily Piestinae (Coleoptera: Staphylinidae) from the Lower Cretaceous of China

Two new Early Cretaceous fossil rove beetle species, Paleosiagonium brevelytratum n. gen. n. sp. and Paleosiagonium adaequatum n. gen. n. sp. are described from the Lower Cretaceous Yixian Formation of Liaoning Province, China. They are clearly placed in the extant Piestinae according to the following characters: body elongate and flat; anterior coxae small and globose; abdomen long and parallel-sided, with six visible sterna and one pair of paratergites on segments III–VII. This is the first report on the occurrence of the coleopteran subfamily Piestinae in the fossil record. The new discoveries indicate that Piestinae have originated at least by the Early Cretaceous, at about 125–120 Ma.     

New Fossil Procercopidae (Hemiptera, Cicadomorpha) from the Early Cretaceous of Northeastern China

A new fossil species,Anthoscytina macula sp.nov.,of the family Procercopidae is described from the Early Cretaceous Yixian Formation in Huangbanjigou,Chaomidian Village,Beipiao City,Liaoning Province,China.A key to the species of the genus Anthoscytina Hong,1983 is provided.The diagnosis of the genus is revised.     

辽西地区义县组昆虫化石及其生物地层、古生态学意义

作为热河昆虫群的重要组成部分,辽西地区义县组昆虫化石内容独特、丰富,共有49科83属,明显区别于同属热河昆虫群的大北沟组和九佛堂组,生物地层单位称为Epheeropsis trisetalis-Sinaeschnidia cancellosa组合,时代为晚侏罗世晚期-早白垩世早期.昆虫群反映了当时温暖而潮湿的气候环境及因地形不同引起的小气候的存在.     

福建永安坂头组植物及古气候分析

分析了福建永安盆地早白垩世坂头植物群的组成特征。共计报道该植物群化石24属52种左右,包括未定种以及存疑种21个。植物群的组成以具鳞片状叶的松柏类化石为主,苏铁类化石次之,并以本内苏铁目占绝对优势,然后是真蕨类化石,以小羽片小而质厚为特征,银杏化石及其少见,未发现被子植物。坂头组植物的组成面貌与欧洲Wealden植物群、日本外带领石植物群,以及我国南方植物区,如浙江、山东等地的早白垩世植物群比较一致,说明坂头组含化石层位年龄为早白垩世早期。坂头组大多数植物主要分布于热带或亚热带地区,具有耐干旱炎热的特点,反映了较干旱而炎热的气候特征。除此之外,还发现少量适宜生活在温凉潮湿气候环境下的植物。根据这些对气候具有指示意义的代表分子在坂头组中的数量以及分布情况,推断永安盆地早白垩世早期气候总体上比较干旱炎热,且伴随有不同程度季节性的潮湿。     

辽西地区土城子组-义县组地层划分对比及时代讨论

本文介绍了辽西中生代土城组、张家口组、义县组地层特征、化石组合。通过岩石地层、生物地层、同位素年代学研究,并在宁城道虎沟地区的张家口组沉积层中采到的化石组合和同位素年龄多数反映时代为晚侏罗纪;义县组生物化石组合和同位素年龄反映时代为早白垩纪。故将侏罗纪与白垩纪界线置于张家口组与义县组之间,同国际年表年代界限（145.5 Ma）相一致。     

义县组研究的新认识

辽西地区义县组是一套中生代陆相火山-沉积岩系,主要由中-基性火山熔岩、火山碎屑岩及湖泊相(包含少量的河流相)沉积岩构成。依据火山活动的规律性,将义县组划分为4个岩性段,自下而上为：底砾岩 基性-中基性火山岩段;湖相沉积(或称珍稀化石层)岩 中性、酸性火山岩段;基性、中基性-酸性、偏碱性火山岩段和砾岩(包括沉火山角砾岩) 中酸性、偏碱性火山岩段。义县组中包含6个化石层位,其中义县组一段的底砾岩和基性、中基性火山岩的(沉)凝灰岩中产有丰富的以鹦鹉嘴龙为主的古脊椎动物化石;二段的湖相沉积岩中含有大量热河生物群化石,包括著名的中华龙鸟、孔子鸟和辽宁古果等珍稀化石,是义县组的最主要化石产出层位,且湖相化石层基本上为同一时期的产物。根据化石研究和同位素测定结果,将义县组的时代定为早白垩世。     

Dispersed angiosperm cuticles: Their history, preparation, and application to the rise of angiosperms in Cretaceous and Paleocene coals, southern western interior of North America

Cuticle — the decay-resistant outer layer of leaves and young stems — provides a reliable means of identifying fossil plant remains and reflects the vegetative adaptations of plants to climate and other environmental parameters. The study of dispersed angiosperm cuticles originated prior to World War II and has focused on the origin and paleoecology of coal. Activity in dispersed cuticles reached a high point during the 1950s and 1960s with the study of Tertiary lignites in central Europe, then subsided in central Europe as workers from other regions expanded the technique to other time-periods and geographic regions. Data from dispersed cuticles augment data from palynomorphs because dispersed cuticles originate from a different generation of the vascular plant life cycle and have different taphonomic histories. Because the analysis of dispersed angiosperm cuticles is unfamiliar to many geologists, methods for the analysis and preparation of dispersed angiosperm cuticles are detailed in an appendix.Dispersed cuticle assemblages from coals in the upper Albian Longford Member of the Kiowa Formation and the Maastrichtian-Paleocene Raton Formation of the Southern Western Interior provide new constraints on the times that angiosperms entered coal swamps and rose to dominance. The Kiowa assemblages indicate that angiosperms first entered coal swamp environments by the late Albian, while the Raton assemblages indicate that angiosperms dominated primary productivity in some subtropical coal swamps by the late Maastrichtian. Angiosperms in Kiowa coals probably comprised pioneer species in conifer-dominated vegetation; the most common family of angiosperms was Chloranthaceae. Angiosperms in upper Maastrichtian Raton coals comprised the dominant seed plants to the exclusion of conifers; magnoliid dicots and monocots were the dominant taxa and comprised diverse genera and families. Evidence from palynology and types of preserved cuticle indicates that ferns were subordinate to seed plants in biomass in Raton coals, in contrast to some described assemblages from the Northern Western Interior. Paleocene coals from the Raton Basin show the loss of many Cretaceous angiosperm taxa as well as the appearance of new taxa, including conifers belonging to Taxodiaceae. However, these Taxodiaceae were evergreen and subordinate in abundance to angiosperms. Vegetational patterns shown by Cretaceous-Paleocene coals of the Southern Western Interior contrast with those of more northerly regions and indicate a poleward gradient in the timing of angiosperm dominance in coal swamps.