New Eoenantiornithid Bird from the Early Cretaceous Jiufotang Formation of Western Liaoning, China

Enantionithine birds are the most blooming branch of early birds and have distinct diversities. A large number of enantionithine birds have been reported from the Early Cretaceous Jiufotang Formation in western Liaoning, China. Recently, we discovered a new eoenantiornithid bird from the Jiufotang Formation in Dapingfang Town, western Liaoning. A new eoenantiornithid bird, Dapingfangornis sentisorhinus gen. et sp. nov., is erected based on this complete skeleton with a skull. The new bird is distinguished from other known Mesozoic birds in a medium to small size, a distinct thorn-like process on the nasals, a sternum with a long and a short lateral processes. The thorn-like process on the nasal has not been discovered among known fossil birds, thus the discovery also provides new materials on the diversities of early birds.

Petrogenesis and Tectonic Significance of Carboniferous Granites on the North Side of the Solonker Suture,Central South Mongolia

The central part of South Mongolia,located to the north of the Solonker Suture,is a key region for studying the late Paleozoic tectonic evolution of the Central Asian Orogenic Belt(CAOB).Voluminous late Paleozoic granitic rocks,especially of Carboniferous age,were intruded in this area.However,these granitoids have not been well studied and there is a lack of precise ages and isotopic data.This has hampered our understanding of the tectonic evolution of southeastern Mongolia,and even the entire CAOB.In this paper,we provide new U-Pb isotopic ages and geochemical analyses for these Carboniferous granites.One granite from the Ulaanbadrakh pluton yielded a zircon U-Pb age of 326 Ma,which indicates emplacement in the Early Carboniferous,and three other granites from the Khatanbulag region gave zircon U-Pb ages of 316 Ma,315 Ma,and 311 Ma,which indicate emplacement in the Late Carboniferous.The Early Carboniferous granite has SiO2 contents of 70.04–70.39 wt%and K_(2)O+Na_(2)O contents of 6.48–6.63 wt%,whereas the Late Carboniferous granites have more variable compositions(SiO2=65.29–77.91 wt%and K2O+Na2O=5.30–7.27 wt%).All the granites are weakly-peraluminous I-types that are relatively enriched in U,Th,K,Zr,Hf,and LREEs.The whole rock Sr-Nd and zircon in situ Lu-Hf isotope analyses for the Early Carboniferous granite gave positive values ofεNd(t)(2.87)andεHf(t)(4.31–12.37)with young Nd(TDM=860 Ma)and Hf(TDMc=1367–637 Ma)two-stage model ages,indicating derivation from juvenile crustal material.In contrast,the Late Carboniferous granites had more diverse values ofεNd(t)(–4.03 to 2.18)andεHf(t)(–12.69 to 5.04)with old Nd(TDM=1358–1225 Ma)and Hf(TDMc=2881–1294 Ma)depleted mantle two-stage model ages,suggesting derivation from remelting of Precambrian basement.Based on the existing results,the tectonic setting of the Late Carboniferous granites in the central part of South Mongolia is known for its diversity,and this paper believes that the tectonic background of the carboniferous granite records the tectonic transition from a continental-margin-arc to a postcollisional extensional setting during the Late Carboniferous–Permian.

First Discovery of Dicerorhinus sumatrensis from Yanjinggou Provides Insights into the Pleistocene Rhinocerotidae of South China

The Rhinocerotidae is one of the most common and important families in the Pleistocene mammalian fauna of South China.Since the last century,most of the Pleistocene rhinocerotid fossils were prematurely assigned to Rhinoceros sinensis,which has resulted in confusion of taxonomy for decades,especially in South China.The Yanjinggou area in Chongqing Municipality of China,where the neotype of R.sinensis came from,has yielded abundant rhinocerotid fossils and is a key area to solve this problem.A recently discovered juvenile skull from a karstic fissure in this area can be referred to Dicerorhinus sumatrensis(Fischer,1814),which is the first confirmed non-Rhinoceros rhinocerotid from the area.This new finding indicates that non-Rhinoceros fossils might have been mixed in AMNH collection from Yanjinggou and thus the diagnosis of Rhinoceros sinensis needs reformation.On the other hand,Stephanorhinus?kirchbergensis is also detected in Granger’s collection based on our reobservation.The coexistence of Rhinoceros,Dicerorhinus and Stephanorhinus shows the higher diversity of Pleistocene rhinocerotids in South China.

Concerning the Original Viewpoint of Biogeologic Accumulation of the Old Bedded Phosphorites in the Khubsugul and Zavkhan Basins of Mongolia

This paper concerns deals with?biogeologic?accumulation and their peculiarities, lithological unites of the phosphorite-bearing formations of these basins and an evolution of the old biota. Old bedded phosphorites are believed to be connected with specific biogeological events happening in the Neoproterozoic glaciation, which was followed by rapid deglaciation,?Ediacaran bioradiation and the “great” postglacial transgression bearing phosphorites at its initial phase. The Mongolian phosphate basins give evidence of this phenomenon. Khubsugul basin is located in the northern Mongolia. The Neoproterozoic-Cambrian phosphorite-bearing khubsugul group is subdivided into 3 formations as ongolik, kheseen and erkhelnuur which are rich in organic fossils (a group of cyanobacterial mats, archaeocyaths, trilobites) in the ascending order. The Zavkhan basin lies in the western Mongolia. The Ediacaran-lower Cambrian sediments are divided into five formations: Maikhanuul (diamictites), Tsagaanolom (phosphorite-bearing carbonate), Bayangol, Salaanygol and Khairkhan. All the formations contain the paleontological fossils (algae, sponges, cyanobacterial mats, ichnocoenosis, soft-bodied fauna, archaeocyaths, etc.). Bedded phosphorites are the object for comprehensive research of bacterial paleontology. It is shown at example of the Mongolian Khubsugul and Zavkhan sea shelf phosphate basins. The expounded actual material clearly shows that the heterogeneous biologic activity, suitable geologic (transgressive systems tracts) and paleogeographic (glaciations, warm climate, etc.) conditions played an important role in the formation and accumulation of the biogenic bedded phosphorites.

An Outline and New Aspects of the Regional Stratigraphy of Mongolia

This paper concerns deals with the Mongolian regional stratigraphic classification of sedimentary, sedimentary-volcanogenic sediments, and metamorphic complex spread over the territory of Mongolia according to the new International Chronostratigraphic Chart [1]. The regional stratigraphy of Precambrian-Cenozoic rocks of the Mongolian territory was studied by Dorjnamjaa et al. [2]. So, this paper provides for the stratigraphy and correlation of key sections through the Archean-Proterozoic-Mesozoic-Cenozoic of various areas of Mongolia. In this paper, the author introduces the most important results indicating the key reference sections for the first time and put into a broad regional context. The characterization and geologic mapping of lithological units provided an essential basis for the lithostratigraphy, biostratigraphy and chemostratigraphy. Especially key biostratigraphic aspects are the phenomenon of faunal succession. The basic lithostratigraphic unit is the formations and groups which have been successful mapped. At present in Mongolia for Precambrian period (systems and series) 30 formations and groups, for Paleozoic—about 250 formations and groups, for Mesozoic—102 formations and groups, for Cenozoic—27 formations, members, and beds are distinguished. The auxiliary stratigraphic units are members, beds which should be mapped depending on great extent of detailed study. In the regional stratigraphical classification, there are two primary kinds of stratotypes [3]: a) unit stratotypes, which serve as the standard of definition for a stratigraphic unit, and b) boundary stratotypes, which serve as the standard of definition for a stratigraphic boundary. These aspects, in particular gradational boundaryas far as possible were examined for example for Archean-Paleoproterozoic (by geochronologic data), Ediacaran-Early Cambrian (by soft-bodied fossils, trace fossils and small shelly fossils), Ordovician-Silurian (by beyrichiidostracodes), Devonian-Carboniferous (by conodonds), Paleocene-Eocene (by mammals), Oligocene-Miocene (by small rodents) systems and series.

Pollen and Spores from the Lower Cretaceous of Central Mongolia and Their Paleoclimatic Significance

The present study focuses on the Lower Cretaceous Khukhteeg Formation (Central Mongolia), which yields palynological assemblage that is used to understand the paleoclimate. Palynology samples from the Khovil opencast mine Choir-Nyalga Basin in the Central Mongolia have been analyzed for palynomorphs with SEM. The assemblage is dominated by pollen to conifers, such as Pinaceae, Podocarpaceae and Taxodiaceae, indicating the vegetation of conifer forests. The assemblage contains abundant spores Schizaeaceae, Cyatheaceae, which are generally associated with wet habitats. According to the detailed analyses, the plant community indicates that warm and humid subtropical paleoclimate controlled the study area during the Early Cretaceous.

Paleogene integrative stratigraphy,biotas,and paleogeographical evolution of the Qinghai-Tibetan Plateau and its surrounding areas

The Paleogene is a crucial period when terrestrial and marine ecosystems recovered from major disruptions and gradually approached their modern states.In the Qinghai-Tibetan Plateau and its surrounding regions,the Paleogene also represents a significant phase of tectonic evolution in the Qinghai-Tibetan Plateau-Himalaya orogeny,reorganization of Asian climates,and evolution of biodiversity.Due to limitations in research conditions and understanding,there are still many controversies regarding stratigraphic divisions in the Qinghai-Tibetan Plateau and its surrounding regions.In recent years,extensive studies on sedimentary petrology,magnetostratigraphy,and isotope dating have been conducted in the region.Numerous fossils have been discovered and reported,contributing to a more systematic understanding of biostratigraphy.These studies have laid a solid foundation for the comprehensive investigation of the stratigraphy,biotas and paleogeographic evolution of the Qinghai-Tibetan Plateau and its surrounding regions during the Paleogene.In this paper,we integrate recent research on fossils,isotopic dating,magnetostratigraphy,and geochemistry to refine the stratigraphic divisions and correlation framework of different tectonic units in the region,building upon previous studies.Since the Second Tibetan Plateau Scientific Expedition and Research,the knowledge of Paleogene floras has gradually expanded.This paper discusses the biostratigraphic significance of extinct and newly appeared taxa based on the latest dating results of these plant species.The new understanding of fossil species such as the“Eucalyptus”and Arecaceae establishes connections between the Paleogene flora of the Qinghai-Tibetan region and the biotas of Gondwana,specifically Oceania and South America.The evolutionary history of key taxa near the Yarlung Zangbo suture zone indicates that the collision between the Indian and Eurasian plates occurred approximately 65-54 Ma.Paleoelevation reconstructions,based on plant fossils,suggest that the Hengduan Mountain had already formed their current topographic pattern prior to the Early Oligocene.The warm and humid lowlands adjacent to the main suture zones in the Paleogene Qinghai-Tibetan Plateau served as the primary pathway for biota exchanges.The relatively low elevation of the Himalaya during the Paleogene did not effectively block the moisture from the Indian Ocean.

关岭及相关生物群沉积与生态环境的探讨

根据近年来对黔东南至滇东关岭、兴义、贞丰和罗平等地中-晚三叠世含海生爬行动物骨架和(或)深水海百合黑色岩系(通常所称黑色页岩)化石库的研究,现将该区岩石地层单位划分,以及这些黑色岩系化石库生物组合特征、时代、分布、沉积和古地理环境概括如下:1)在关岭—兴义地区中-晚三叠世(安尼期、拉丁期和早卡尼期)地层中,至少夹有3层、甚至4层含海生爬行动物的黑色岩系化石库(或黑色"页岩"化石库),自下而上产盘县生物群、兴义生物群和关岭生物群。云南罗平地区中三叠统关岭组中新发现的"罗平生物群"与盘县生物群层位大致相当。贞丰龙场赖石科组上部新挖掘出的30m厚产创口海百合、双壳类及菊石的黑色岩系,应该是研究地区最高层位的海相三叠纪黑色岩系,时代似属晚三叠世早卡尼期晚期;2)推测这些含海生爬行动物骨架的黑色岩系化石库是在印支造山运动影响下,伴随南盘江前陆盆地隆升和闭合,在扬子克拉通台地边缘所形成的一个或几个边缘凹陷、或边缘盆地之中形成的,这些凹陷或盆地形成之初,表层水充氧,且具有很好的食物链结构,有利于各类海生生物生活;后来的海平面上升至最大海泛期,以及由此引起缺氧和含硫化氢水位的上升,导致这些凹陷逐渐变成安静、滞流的死亡之海和黑色岩系化石库;3)关岭生物群产于晚三叠世卡尼期早期小凹组下段上部黑色岩系之中,是一个典型的在滞流、缺氧且海底没有食腐动物边缘局限盆地中所形成的黑色页岩化石库,以产大量海生爬行动物和深水假浮游海百合为特征,此外还有个别的两栖类和原始龟类发现;4)产于竹杆坡组近底部黑色岩系中的兴义生物群,以产大量肿肋龙类为特点,尤以个体较小的贵州龙最为常见,共生的还有多种鱼类化石,在生物组合和产出层位上,可与阿尔卑斯南部Meride灰岩所夹黑色含沥青页岩化石库对比,时代似应归属拉丁期早或中期;大量米虾在竹杆坡组近底部含贵州龙层的发现,推测兴义生物群可能形成于台地边缘早期并不缺氧,且具有理想食物链结构的浅水、超盐的凹陷或盆地之中。由于存在浮游生物—虾—贵州龙—欧龙—虾—浮游生物所组成的生态组合和食物链结构,从而为解释以肿肋龙类为代表的兴义生物群的繁衍和多生提供了依据;接踵而来的沉积速率下降和缺氧水位的上升,以及间歇性火山作用,导致该特有生态体系的崩溃和化石库的形成。根据对贞丰挽澜竹杆坡组底部首次发现的棘皮动物的化石库的研究,指出该化石库系由海星、细小蛇尾、底栖海百合茎、海胆和海参等5类棘皮动物化石和含贵州龙骨架碎片组成,其下为8m厚夹有薄层的骨层的凝缩层沉积,后者位于硬底之上。此种沉积和埋藏模式与德国上壳灰岩早拉丁期的棘皮动物化石库类似,是在近岸海水不太浅的内陆棚的环境下,由于风暴潮作用所形成的化石库,他们与在滞流、缺氧海底、通过化石聚集所形成的化石库是不同的;5)产盘县生物群的黑色岩系化石库主要见于盘县羊件和普安青山中三叠世(安尼期)关岭组中,与云南罗平地区的"罗平生物群"在层位及生物组合上大致相当,均以含大量混鱼龙、幻龙和欧龙,以及鱼类为特点,共生的还有大量节肢动物。所不同的是后者由于靠近滨岸,故而出现大量幼年期的鱼类以及虾类和鲎类化石,推测他们形成于靠近古陆或滨岸的台缘浅水表层充氧的正常、且有时超盐的凹陷之中,时代上早于阿尔卑斯南部安尼期/拉丁期比塞娄组;其集群死亡除因后期盆地滞流、缺氧外,可能还与风暴和火山作用有关。

Meganodular Limestone Points South China Paleoplate to the Late Ordovician Equator

Objective Time-specific litho- and biofacies often holds important information about unique ancient ecosystems that no longer exist on Earth today. This report summarizes one of such time-specific facies--the 3-D network structure of the Upper Ordovician Pagoda Formation in South China, as investigated by Zhan et al. （Palaeogeography, Palaeocli-matology, Palaeoecology, DOI： 10.1016/j.palaeo.2015.07.039）.

CAS Paleontologist Presented with L'Oréal-UNESCO Award for Women in Science

Since Charles Robert Darwin’s time,scientists had long thought that terrestrial vertebrates,including humankind itself,had evolved from an intermediate species called lungfish,given that this special species could breathe with either gills or lungs,and this amphibian ability could have offered it advantages over others when adapting to life on land.The framework for exploring the phylogenetic relationships of sarcopterygians and the origin

An early Cambrian Sidneyia(Arthropoda) resolves the century-long debate of its head organization

We report the extraordinarily preserved euarthropod Sidneyia minor sp.nov.from the Cambrian Stage 3 Xiaoshiba Lagerst?tte in Yunnan,South China.So far this is the earliest occurrence of the genus.As with other species of Sidneyia,the new taxon shares similar features such as a crescent-shaped head shield with paired lateral notches for stalked eyes,but more significantly and new,is the presence of three pairs of post-antennal appendages beneath the head shield identified by micro-CT methods.We conclude that Sidneyia is a sister group to other members of Vicissicaudata within the diverse radiation of Artiopoda.

Age and paleoenvironment of Xiaogushan fauna at Haicheng,Liaoning Province

A mammalian fauna composed of 40 species associated with Xiaogushan Man was unearthed during the archaeological excavations from 1981 to 2007 at Xiaogushan Paleolithic Site,Haicheng,Liaoning Province.The analyses of the fauna and comparison with other related faunas indicate that Xiaogushan fauna is very similar to that of Shanchengzi,Gulongshan and Yushu.It is a typical fauna of Northern Region.Its age is within the middle to late stages of the Late Pleistocene(80-20 ka).Influenced by cold period MIS4,the cold forms appeared in the fauna.Nevertheless the decrease in temperature was not very much and the climate was still a temperate one.The fauna's environment was generally humid,with large forest,some water areas and grasslands.It is suitable for prehistoric human habitation during temperate seasons with considerable food and water resources.The cold period MIS4 might push prehistoric human southward to temperate areas or stimulate them to develop fire using and making techniques.

Microfabric features of microbial carbonates:experimental and natural evidence of mold holes and crusts

Results of our study based on examination of induced precipitation of carbonate by a cyanobacterium, Lyngbya in the laboratory, and the analyses of microphotographs of both modern and ancient microbial carbonates,demonstrated the importance of recognition of mold holes and carbonate crusts in understanding microbial carbonates. In the experiment, only cyanobacteria Lyngbya can induce precipitation of carbonate, forming scattered grains on the surface of Lyngbya filaments. Carbonate crusts enclosing the old parts of the filaments were formed through aggregation of these scatter grains while mold holes were formed after decay of the filaments. Mainly based on the experiment, six different ways of microbial carbonate formation were recognized:(1) trapping without mold holes,(2) trapping with mold holes,(3) particle-forming induced-precipitation of carbonate,(4) discrete crustforming induced-precipitation of carbonate,(5) induced precipitation, forming tangled crusts that build a porous construction, and(6) induced precipitation, forming a dense construction. And mold holes and crusts can form in ways(4),(5), and(6). Examination of both modern microbial carbonates from the Shark Bay of Australia, Highborne Cay of Bahamas and the atoll of Kiritimati and the microbialites from the Cambrian dolostone sequence in Tarim,Xinjiang, China all demonstrated the limitation of recognizing only mesofabric features and importance of examining microfabric features for understanding of the genesis of the microbial carbonates and their proper classification. The shape, size and arrangement of the mold holes, crusts, and the features of the minerals filling in pores between the crusts, which are referred as the microfabric features here, are keys to better understand the formation and environments of both modern and ancient microbial carbonates.

Key innovations in ruminant evolution: a paleontological perspective

Key innovations are newly acquired structures that permit the performance of a new function and open new adaptive zones,and are,therefore,of paramount significance for understanding the history of the Ruminan­tia,particularly its diversification through the Miocene.Here we review and discuss what is known about these evolutionary novelties,with special emphasis on the appearance and evolution of cranial appendages and high-crowned(or hypsodont)teeth.Cranial appendages probably favored the diversification of pecorans by be­ing structures strongly related to sexual selection,whereas the acquisition of hypsodont teeth could have ex­panded potential dietary breadth and allowed species to extend diets into the grazing range without eliminating browsing as a potential diet.When analyzed in conjunction with patterns of faunal diversity and in the context of climatic changes,it seems that the overall view that ruminant cranial appendages and hypsodonty may have started responding to increased patterns of seasonality and the opening-up of ecosystems is roughly valid.In­stead,they occurred through several distinct pulses and varied widely among continents.This review is,to our knowledge,the first to highlight that the evolution of these innovations has been far from constant and uniform through time.Furthermore,we identify that both a first attempt to increase hypsodonty starting in the early Mio­cene and a first evolution of antlers and pronghorns were interrupted as a consequence of wide climatic fluctua­tions in the early-middle Miocene transition.

Western Tethyan Epeiric Ramp Setting in the Early Triassic： An Example from the Central Dinarides (Croatia)

In the central part of the External Dinarides in Plavno, Croatia, near Knin, a remarkably thick （927.5 m） Early Triassic depositional sequence was investigated. The Plavno sequence starts in the EarlyGriesbachian and ends with a continuous transition into the Anisian strata. A complete 13C isotope curve has been achieved and combined with conodonts, bivalves and ammonoids to establish and correlate stage and substage boundaries. The 613C curve is consistent with former studies. It displays a general increase from the Griesbachian to a prominent maximum beyond the ＋8%0 amplitude around the Dienerian-Smithian boundary （DSB）, followed by a steep and continuous decline to low, negative values in the Smithian. Around the Smithian-Spathian boundary （SSB） a steep rise to a second maximum occurred. It is followed by a saw-tooth shaped decline in the Spathian and a similar increase to a peak at the Spathian-Anisian boundary （SAB）. Sedimentologically, the Plavno sequence is interpreted as having been deposited on an extensive epeiric ramp under long-term transgressive conditions, sharing depositional characteristics of both the epeiric platform and the carbonate ramp. The entire Plavno sequence was deposited above the storm-wave base and was storm influenced. Three informal members are differentiated： 1） the dolostone member （Early Griesbachian）; 2） the silicielastic member （red-coloured shale, siltstone, sandstone with oolitic/bioclastie grainstone intercalations）, which can be further divided into lower, middle and upper intervals （Late Griesbachian, Dienerian and Smithian）; and 3） the mudstone member （grey lime mudstones, marls and calcisiltites with common ammonoids and gastropods- Spathian）. The Plavno sequence is compared with other western Tethyan sections. Observed differences stem from local controls on deposition in the overall shallow marine environment.

中亚造山带南缘末次大规模侧向增生的机制

中亚造山带是世界上最大的显生宙增生造山带.其古生代形成了巨量的年轻弧地壳物质,然而形成的构造机制和结束时限尚不清楚.南蒙古拼合体系是中亚造山带晚古生代典型的增生造山区,为研究中亚造山带晚期侧向增生提供了理想的窗口.通过对南蒙古东部Khan-Bogd地区的石炭纪火山岩-火山碎屑岩进行精细的岩石学和锆石的U-Pb-Hf和全岩Sr-Nd同位素研究,得出南蒙古石炭纪弧岩浆作用经历了由北向南的迁移,是俯冲板片后撤的产物.结合前人对整个中亚造山带南缘同时期及稍晚的岩浆岩、沉积岩和大地构造的研究,认为该期弧岩浆作用发生在弧后洋盆,并代表了中亚造山带南缘最后一次大规模侧向增生.

How large are the extinct giant insular rodents? New body mass estimations from teeth and bones

The island rule entails a modification of the body size of insular mammals,a character related with numerous biological and ecological variables.From the Miocene to human colonization(Holocene),Mediterranean and Canary Islands were unaltered natural ecosystems,with paleofaunas formed with endemic giant rodents among other mammals.Our aim is to create methods to estimate the body masses of fossil island rodents and address the nature of ecological pressures driving the island rule.We created regression equations based on extant ro-dent data and used these to estimate the body masses of the extinct species.Our results show strong correlations between teeth,cranial and postcranial measurements and body mass,except for the length of the long bones,the transversal diameter of the distal tibia and the anteroposterior diameter of the proximal tibia,where the equa-tions were less reliable.The use of equations obtained from a more homogeneous group(suborder and family)is preferable when analyzing the area of the first molar.The new regressions were applied to estimate the body masses of some Mediterranean and Canarian fossil rodents(Canariomys,C.bravoi 1.5 kg and C.tamarani 1 kg;Hypnomys,H.morpheus 230 g and H.onicensis 200 g;and Muscardinus cyclopeus 100 g).Our results indi-cate that under absence of predation,resource availability(island area)is the key factor that determines the size of the Canariomys sp.However,under presence of specialized predators(birds of prey),body size evolution is less pronounced(Hypnomys sp.).

On the relationship between hypsodonty and longevity in Myotragus balearicus–A comment on van der Geer (2014)

In a recent paper published in a special issue of Integrative Zoology on‘Paleontology and evolution–part I.’(Palombo 2014),the author(van der Geer 2014)takes a review of the derived traits observed in endemic fossil insular mammals,including body size variation,cranial and postcranial changes,and modifications in dentition.At one point in the discussion,the author misinterprets and seriously distorts statements by Jordana et al.(2012)on the relationship between hypsodonty and longevity in the fossil insular bovid Myotragus balearicus Bate,1909.

Halysis Høeg,1932—An ancestral tabulate coral from the Ordos Basin,North China

The problematic calcareous microfossil Halysis is abundant in the Middle Ordovician Darriwilian Stage of the western edge of the Ordos Basin,North China.The rich and well-preserved specimens of Halysis in this area facilitate detailed studies for its skeletal construction and tube microstructure.Halysis differs from calcified cyanobacteria and calcareous red and green algae in morphology,skeletal construction and microstructure,as well as reproduction mode.Halysis typically consists of multiple juxtaposed parallel tubes arranged in sheets(‘multiple-tube'type)or is just composed of one tube(‘single-tube'type).In‘multiple-tube'Halysis,tube fission by bifurcation results from the insertion of a microcrystalline wall at the center of a mother tube.This study demonstrates for the first time that the tube walls of Halysis have a laminofibrous(fibronormal)microstructure,composed of fibrous calcite perpendicular to wall surface,and recognizes the‘single-tube'type Halysis composed of one tube;in addition,for the first time,this study finds out that‘multiple-tube'Halysis develops buddings from the conjunction of two tubes and‘single-tube'Halysis shows wide-angle Y-shaped branchings.Based on these findings,this study further compares Halysis with tabulate corals.Halysis appears stratigraphically earlier than Catenipora and Aulopora,and has a smaller tube size.‘Multiple-tube'Halysis resembles Catenipora and‘single-tube'Halysis resembles Aulopora in skeletal construction and microstructure,and in their tube walls of laminofibrous microstructure composed of fibrous calcite perpendicular to the tube wall surface.Catenipora and Halysis are both characterized by the absence of septal spines.The similarities suggest that Halysis may be the ancestor of Catenipora-like and Aulopora-like tabulate corals.