This paper deals with Jurassic brachiopods from North Tibet and South Qinghai and the stratigraphical subdivision there. Based on faunas and strata,a general outline of the palaeogeographical evolution has been traced...This paper deals with Jurassic brachiopods from North Tibet and South Qinghai and the stratigraphical subdivision there. Based on faunas and strata,a general outline of the palaeogeographical evolution has been traced out along the line of plate-tectonic movements . In this paper , 10 species of 8 genera are described , among which the species Lacunosella rhombica , Rntithyris vulgaris , Tanyothyris appositus , Apatecosia navicularis and Flabellothyris sp . nov . have been recognized as new .展开更多
The middle Permian Cryptospirifer fauna （brachiopod） has hitherto been found in more than 30 localities in the Yangtze Platform, South China. Examination of data from various localities shows that it occurs stratigr...The middle Permian Cryptospirifer fauna （brachiopod） has hitherto been found in more than 30 localities in the Yangtze Platform, South China. Examination of data from various localities shows that it occurs stratigraphically in three intervals in the range from the upper Kungurian to Wordian. In the Baoshan block in western Yunnan the fauna occurs in the basal part of the Daaozi Formation and is of possibly an early Wordian age. Outside China the Cryptospirifer fauna has been reported from central and northwest Iran and central Turkey, where the fauna may have an age around the Wordian／Capitanian boundary. Rapid global warming since the late Early Permian and possession of other suitable environmental factors such as proper substrate, clastic input and water depth enabled the Gondwana-derived Baoshan Block and related tectono-stratigraphic units in Iran and Turkey to host the Cryptospirifer fauna, a fauna evolved in the Yangtze Platform that is a type area of the Cathaysian province.展开更多
By reasearch on geographic distribution, nine genera in bipolar distribution are selected from Permian brachiopods. These taxa originated from middle-high latitude areas in the boreal realm, of which five genera were ...By reasearch on geographic distribution, nine genera in bipolar distribution are selected from Permian brachiopods. These taxa originated from middle-high latitude areas in the boreal realm, of which five genera were derived from Late Carboniferous, and other four genera originated from Permian. They were all in bipolar distribution during some different stages in Permian. Specific diversity for each genus was high in the boreal realm, whereas in the Gondwana realm was very low. Perdurability was long in the boreal realm, and short in the Gondwana realm. It was the time when these nine genera came to their maximum diversity that these genera appeared in the Gondwana and formed bipolar distribution; while they also migrated to the low latitude from high latitude. This shows very close relationship between several main cooling events in Permian and the migration of genera from the boreal realm to the Gondwana reahn through the Tethys. Therefore, the cooling events might be the main drive which caused these cold-water-type brachiopods migrated to the Gondwana realm and being bipolar distribution. In this process, the planula tolerance to warm water would be another important factor.展开更多
The Cambrian explosion was coined to describe the geologically sudden appearance of numerous bilaterian body plans(Phyla)around the Ediacaran-Cambrian transition,around 565-520million years ago.Many explanations and c...The Cambrian explosion was coined to describe the geologically sudden appearance of numerous bilaterian body plans(Phyla)around the Ediacaran-Cambrian transition,around 565-520million years ago.Many explanations and conjectures have been postulated in order to explain the pattern and duration of this explosive radiation of many different phyla of early metazoans.Here,we focus on the evolution of a phylum of marine suspension-feeding animals—the brachiopods,as exemplified by the exceptionally preserved taxa from the celebrated Chengjiang Konservat Lagerst(a|¨)tte(Yunnan,China).The abundant soft-bodied preservation at these fossil quarries gives us the only firm insights into what brachiopods looked like and how they functioned and lived when they first appeared on the Earth.Studies of Chengjiang brachiopods demonstrate that the early animals developed a remarkably varied organization of tissues and organs shortly after the onset of Cambrian explosion.In the marine suspension-feeding brachiopods,most importantly the tentaculate feeding structure of early brachiopods is already differentiated into two shapes of lophophore,anteriorly coiled(spiralled)and posteriorly arching tentacle crowns and the unique latter type was previously not documented from fossil and living brachiopods.Also unlike any known Recent brachiopod,all the known Cambrian brachiopods from Chengjiang have an open digestive tract that was disposed either as a Ushaped gut in linguliform and stem group brachiopods,or straight gut with a posterior anus in some calcareous-shelled stocks.Moreover,in contrast toliving lingulids,all the Cambrian brachiopods have an epibenthic lifestyle either cemented by a ventral valve or attached by variable pedicles to establish complex ecological community encompassing primary tierers and variable secondary tierers.It is therefore assumed that brachiopods were the first benthic metazoan that achieved their success in ecological stratification and tiering complexity by late Atdabanian.The setae are also important for the brachiopod suspension-feeding life style,and in the Chengjiang braehiopods they include two types cilia-like and spine-like setae.The mantle canals of different braehiopod species are also distinctly variable in arrangement,mainly disposed in pinnate,baeulate and peripheral conditions.Of these,the peripheral disposition of mantle canals is for the first time proposed here so as to differentiate from the bifurcate condition in recent lingulids in that the former is devoid of posteriorly extending main trunks of sinus,but possesses a diverging dorsal vascula media in dichotomy.展开更多
The abundance curves derived from area proportions of brachiopods and Girvanella in the thin sections from the Yangdi section, South China, exhibits complex relationships during the Late Devonian Frasnian-Famennian tr...The abundance curves derived from area proportions of brachiopods and Girvanella in the thin sections from the Yangdi section, South China, exhibits complex relationships during the Late Devonian Frasnian-Famennian transition. The living activity of brachiopods such as grazing and borrowing did great damage to the growth of Girvanella. However, there was more to just a mere a survival competing relationship between them, Girvanella actually improved marine environments by oxygenating the dysoxic ambient sea-water through photosynthesis in the lower Kellwasser Horizon. Profited from this improvement brachiopods' abundance increased subsequently and suppressed Girvanella again. Nonetheless, without Girvanella's photosynthesis, brachiopods were wiped out by the farther anoxic environments in the upper Kellwasser Horizon. The complex relationships between Girvanella and brachiopods may be a key to unlocking the relationships between geomicrobes and metazoans in the geological overturn periods.展开更多
That the contents and compositions of trace elements, especially REE in sedimentary rock and agustite originating from inarticulate brachiopods, conodont, etc. change in the vertical direction usually has a close rela...That the contents and compositions of trace elements, especially REE in sedimentary rock and agustite originating from inarticulate brachiopods, conodont, etc. change in the vertical direction usually has a close relation with the stratigraphic boundary of important biologies. This paper systematically analyses REE and 16 trace elements such as U, Th, Sr, Ba, Co, Ni, Cr, V, Cu, Pb, Zn, Sc, Au, As in sedimentary rocks and the agustite on the standard stratified section of the Cambrian-Ordovician Boundary in Dayangcha, Huniiang, Jilin Province. Based on this, the authors investigate the REE distribution pattern and the law of the contents and compositions of trace elements changing, providing the geochemical evidence for building stratified sections of the Cambrian-Ordovician boundary and discussing sedimentary environments.展开更多
The relationship between species diversity and ecosystem function is a hot topic in ecology and environics. This paper investi- gates the evolution of diversity of the late Middle Permian brachiopods community in Hech...The relationship between species diversity and ecosystem function is a hot topic in ecology and environics. This paper investi- gates the evolution of diversity of the late Middle Permian brachiopods community in Hechuan, Chongqing, China, and dis- cusses the relationship between species diversity and community productivity in terms of the geohistorical development. This paper shows that the species diversity is externalized by several indexes, and the relationship between diversity and productiv- ity is too complex to be described by a single assumption. The relationship between species diversity and community produc- tivity is restricted by environment and community evolution. When the community succeeds normally, the relationship be- tween species richness index, species diversity index, and species evenness index to productivity is in linear dependence rela- tion to each other, which is met with the third assumption. But, when the environment interference surpasses the beating capa- bility of the community, not only the community succession will be terminated and be replaced by another one, but also the relationship between species richness index, species diversity index, and species evenness index to productivity is also in- versed to negative correlation by the interference from environment. Only the relationship between ecological dominance and productivity is in linear dependence relation to each other and approximately met with the third assumption. It is illustrated that the assumption that the productivity is in linear dependence relation with diversity should be established on the presupposition that the community succession is normal.展开更多
A continuous Ordovician-Silurian boundary section from the upper Wufeng Formation through the Kuanyinchiao Formation to the lower Lungmachi Formation has been carefully measured and collected at Shuanghe of Changning,...A continuous Ordovician-Silurian boundary section from the upper Wufeng Formation through the Kuanyinchiao Formation to the lower Lungmachi Formation has been carefully measured and collected at Shuanghe of Changning, southern Sichuan Province. For the first time, the temporal changes of α- and β-diversities of the Hirnantia fauna have been discussed in great detail. The general trend of brachiopod diversity change, increasing upward, is consistent with the regional trend of the Yangtze Platform, which had been controlled by both intrinsic and extrinsic factors. However, the sudden drop of diversity for a short period in the upper Kuanyinchiao Formation might have been controlled by environmental factors rather than normal faunal turnover. Synecological analysis using numerical methods recognizes two brachiopod-dominated associations of the Hirnantia fauna, the Dalmanella-Kinnella Association and the Mirorthis Association, both living in an offshore, deeper water environment corresponding to BA3-upper BA4, particularly lower BA3.展开更多
Information on latest early Olenekian(latest Smithian)ammonoids is available apparently from only seven regions of the world,including South Primorye.Latest Smithian evidences on this topic are recorded from the West ...Information on latest early Olenekian(latest Smithian)ammonoids is available apparently from only seven regions of the world,including South Primorye.Latest Smithian evidences on this topic are recorded from the West SMID(abbreviation from the Russian name of the quarry:"Building Materials and Details"),East SMID and Golyj Cape areas in South Primorye.This provides additional information on systematic composition of latest Smithian ammonoid,as well as conodont and brachiopod assemblages from the recently identified Shimanskyites shimanskyi Zone,located between lower Olenekian Anasibirites nevolini Zone and upper Olenekian Tirolites subcassianus Zone.There are many common ammonoid species in the Shimanskyites shimanskyi Zone and the underlying Anasibirites nevolini Zone,e.g.,Prosphingitoides sp.,Arctoceras septentrionale(Diener),Churkites syskoi Zakharov et Shigeta,Submeekoceras?subhhydaspis(Kiparisova),Prionites markevichi Zakharov et Smyshlyaeva,?Anasibirites?simanenkoi Zakharov et Smyshlyaeva,Xenoceltites?subvariocostatus Zakharov et Smyshlyaeva,and Mianwaliites zimini Zakharov et Smyshlyaeva.The base of the Shimanskyites shimanskyi Zone,marked by a negativeδ13Corg excursion in the Kamenushka-2 Section by our previous study,coincides with the FO(first occurrence)of ammonoids Shimanskyites shimanskyi Zakharov et Smyshlyaeva and Glyptophiceras cf.sinuatum(Waagen)and conodont Hindeodella budurovi Buryi.This zone is characterized additionally by some fossils common for the overlying upper Olenekian Tirolites subcassianus Zone:ammonoids of the genus Kamenushkaites,brachiopods Bittnerihyris margaritovi(Bittner)and Lepismatina sp.and conodont?Neogondolella?(=?Borinella)jubata Sweet.The latest Smithian ammonoids recorded from the Shimanskyites shimanskyi Zone totally consist of 30 taxa belonging to 11 families(Sageceratidae,Ussuiriidae,Aspenitidae,Paranannitidae,Arctoceratidae,Proptychitidae,?Galfetitidae,Prionitidae,?Kashmiritidae,Xenoceltitidae and Palaeophyllitidae).The problems of global correlation of uppermost Smithian strata are also discussed.展开更多
Abstract The alleged ＂holotype＂of the bivalve Yangtzedonta primitiva Yu.1985 figured by Qian （2001） is a broken and distorted specimen of the brachiopod Xianfengella prima He and Yang, 1982 and not the holotype of...Abstract The alleged ＂holotype＂of the bivalve Yangtzedonta primitiva Yu.1985 figured by Qian （2001） is a broken and distorted specimen of the brachiopod Xianfengella prima He and Yang, 1982 and not the holotype of Y. primitiva. Qian contends that the oldest recognized monoplacophoran, Maikhanella pristinis （Jiang, 1980）, is neither a monoplacophoran nor the oldest molluscan fossil in the Meishucunian Stage of China. Furthermore, he considers that the oldest bivalve Xianfengoconcha eUiptica Zhang, 1980 is an inarticulate brachiopod, not a mollusc. WatsoneUa yunnanensis （He and Yang, 1982）, is associated with Yangtzedonta primitiva Yu but indicates no evolutionary relationship between the Classes Rostroconchia and Bivalvia in the Lower Cambrian Zhongyicun Member of the Yuhucun Formation. Qian＇s confusion in using non-molluscan fossils to discuss the early evolution of shelled molluscs also confuses the basic concepts of the respective groups.展开更多
Data obtained on conodont distribution in the Permian-Triassic Sovetashen Section of Transcaucasia provide further limitations on the age of the carbon-isotopic anomalies discovered by Baud et al. (1989). The signific...Data obtained on conodont distribution in the Permian-Triassic Sovetashen Section of Transcaucasia provide further limitations on the age of the carbon-isotopic anomalies discovered by Baud et al. (1989). The significance of Caucasian sections for working out the carbon-isotope standard for the Upper Permian and Lower Triassic (Induan) is shown. Original data on carbon-isotope composition of bivalve and brachiopod shells from Permian sediments of North-Eastern Russia (Omolon and Okhotsk areas) have been obtained, which may be used for their correlation.展开更多
The stratotype region of the Ryazanian stage is located in the Oka River Basin near Ryazan, Central Russia. Since ammonites are very well studied here, we investigated other groups of macrofossils. We report a large n...The stratotype region of the Ryazanian stage is located in the Oka River Basin near Ryazan, Central Russia. Since ammonites are very well studied here, we investigated other groups of macrofossils. We report a large number of bivalve genera: Arctica, Astarte, Buchia, Camptonectes, Chlamys, Ctenostreon, Entolium, Gomomya, Gresslya, Hartwellia, Lima, Meleagrinella, Modiolus, Oxytoma, and Pleuromya. The belemnites are represented by two cylindroteuthidid genera, Acroteuthis and Liobelus. In addition, brachiopods (Rhynchonellidae and Terebratulidae) and unidentifiable gastropod fragments have been revealed. The highest taxonomic diversity of macrofauna is observed in the Surites spasskensis ammonite Zone.展开更多
Tuvaella brachiopod fauna are distributed in an arc in three areas, including the Zeya-Hailar （海拉尔）-Shinejinst area, the Najramdal Uul-Kyzyl area, and the Barkol-Fuyun （富蕴） area. The Tuvaella fauna in the Ze...Tuvaella brachiopod fauna are distributed in an arc in three areas, including the Zeya-Hailar （海拉尔）-Shinejinst area, the Najramdal Uul-Kyzyl area, and the Barkol-Fuyun （富蕴） area. The Tuvaella fauna in the Zeya-Hailar-Shinejinst area are distributed in the northern margin of Jiamusi （佳木斯）-Mongolia block along the Mongolia-Okhotsk suture between the Siberia plate and the Jiamusi-Mongolia block but not appear in the corresponding Siberia plate. The Tuvaella fauna in the Najramdal Uul-Kyzyl area are distributed in the southwestern part of the Siberia plate as the accelerated fold belts during the Salairian-Caledonian periods, and those in the Barkol-Fuyun area are distributed in the northeastern margin of Kazakhstan plate. They are distributed along the Irtysb suture between the Siberia plate and the Kazakhstan plate. The Tuvaeila fauna became domestic fauna during the Wenlock and Pridoli （Middle-Late Silurian） and form a unique biogeographic province, i.e., the Mongolia-Okhotsk Province. This biogeographic province is sustained to the Mississippian （Carboniferous）, perhaps due to the semiclosed state of the Mongolia-Okhotsk Ocean. The northeastern margin （right now the southwestern margin） of Siberia plate, the northern margin of Jiamusi-Mongolia block, and the northeastern margin of Kazakhstan plate might be conjuncted in an arc region from Wenlock to Mississippian, along the southern margin of the Irtysh-Mid Mongolia-Okhotsk Ocean. This is coincident with the fact that the Siberia plate rotated 180° clockwise since the Mesozoic and located in the middle-high latitude during Devonian, and the coral reef limestone is widely developed in the Jiamusi- Mongolia block during the Early and Middle Devonian, which suggests that the block was positioning in middle-lower latitude at that time and that the Kazakhstan plate was also located in low latitude then.展开更多
A comprehensive compilation and systematic analysis of known early and middle Permian brachiopod faunas shows that the early Permian brachiopod faunas comprise three realms,six regions,and eleven provinces,while those...A comprehensive compilation and systematic analysis of known early and middle Permian brachiopod faunas shows that the early Permian brachiopod faunas comprise three realms,six regions,and eleven provinces,while those of the middle Permian comprise three realms,four regions,and eight provinces.A comparison and analysis of brachiopod faunal patterns reveal a coevolution between global brachiopod paleobiogeography and tectonopaleogeography during the early-middle Permian.Although temperature/latitude is the main factor controlling the formation of three realms,tectonopaleogeographic factors determine the temperature/latitude in which the continents were located.The'continental barrier'of Pangea,as a'central axis'continent,divided the three realms into six regions,which indicates that the formation of biogeographic regions was controlled mainly by the tectonopaleogeographic factors.The evolution of tectonopaleogeography was sometimes a long-term process,so that the biogeographic regions(or provinces)controlled by tectonopaleogeography displayed relative stability.Shifts in the nature of biogeographic provinces(e.g.,from cool water to warm water,and vice versa),extensions or narrowing of geographical ranges,and recombinations of some provinces were all related to regional tectonic evolution.The study of the coevolution between brachiopod paleobiogeography and tectonopaleogeography not only accounts for the formation mechanisms of brachiopod paleobiogeographic patterns during the early-middle Permian,but also provides evidences for the locations and configurations of oceans and plates(blocks)during this period.展开更多
After the End-Permian mass extinction, ammonoids reached levels of taxonomic diver- sity higher than in the Changhsingian by the Dienerian Substage of the Induan. However, brachiopods exhibit a prolonged delay in reco...After the End-Permian mass extinction, ammonoids reached levels of taxonomic diver- sity higher than in the Changhsingian by the Dienerian Substage of the Induan. However, brachiopods exhibit a prolonged delay in recovery, and their taxonomic diversity had not recovered to Late Permian levels even by the Olenekian. The differential patterns of recovery between these two clades may reflect fundamental differences in physiology and behavior. Brachiopods were benthic organisms that were dependent on specific trophic sources, and their general reduction in size during the Early Triassic may have been a response to a relative paucity of food resources. In contrast, ammonoids were sluggish- nektic organisms that utilized a wider range of trophic sources and that suffered no comparable size decrease during the Early Triassic. Brachiopods may have been at a disadvantage also due to vulner- abilities associated with their larval stage, during which they had to locate a suitable substrate for set- tlement. In contrast, ammonoids had no larval stage and juveniles may have been dispersed widely into favorable habitats. These factors may account for differences in the relative success of ammonoids and brachiopods at high-latitude regions following the End-Permian mass extinction： ammonoids success- fully reeolonized the Boreal region during the Early Triassic whereas brachiopods did not.展开更多
Twelve paleocommunities dominated by benthic brachiopod are recognized in the Givetian-Frasnian stages of the Devonian in the Longmenshan area, southwestern China, in which two kinds of brachiopod community replacemen...Twelve paleocommunities dominated by benthic brachiopod are recognized in the Givetian-Frasnian stages of the Devonian in the Longmenshan area, southwestern China, in which two kinds of brachiopod community replacement are classified. One is the abrupt replacement, represented by abrupt alternation between the Leiorhynchus community and Zhonghuacoelia-Striatopugnax community in the Frasnian Tuqiaozi Formation. The other is the gradual one, developed in the Givetian Guanwushan Formation, which had been completed by the shift of the Independatrypa lemma-Uncinulus heterocostellis-Emanuella takwanensis community via the Sinospongophyllum irregulare-Pseudomicroplasma fongi community to the Clathrocoilona spissa-Hexagonaria composite reef community. According to analyses of the paleocommunities, either the abrupt or gradual paleocommunity replacement of the Middle-Upper Devonian in the Longmenshan area is suggested as a response to the 5th-order sea level fluctuation due to the replacements of the paleocommunities in a tracts-system of depositional sequence. It is supposed that changes of paleocommunity diversity, one of the results of paleocommunity replacement, are depended on the range and magnitude of sea level fluctuation, but there is not a linear relationship between them. Furthermore, a suggestion is proposed that the concept of paleocommunity succession seem to be abandoned in the paleocommunity analysis because it almost never be practiced to recover the information of community succession in the geological record at present.展开更多
The Kungurian-Capitanian （Permian） Zhesi branchiopod fauna is mainly composed of cold-water typed taxa with high diversity and abundance. This fauna is similar with the coeval brachiopod faunas from Ti- man-Pechora,...The Kungurian-Capitanian （Permian） Zhesi branchiopod fauna is mainly composed of cold-water typed taxa with high diversity and abundance. This fauna is similar with the coeval brachiopod faunas from Ti- man-Pechora, Svalbard, and Queen Elizabeth Islands of the Boreal Realm, with no real ＂warm-water＂ species. Zhesi brachiopod fauna is a cold-water fauna and should be assigned to the Boreal Realm. Considering the paleogeographic characteristics of this fauna and the basic rationale of paleobiogeographie provinces being controlled by latitude-temperate, and that the above areas were located at 50°N -70°N in the global paleoclimate reconstruction map compiled by Boucot et al. , the paleo-latitude of the southern margin of Jiamusi-Mongolia Block, where developed the Zhesi brachiopod fauna, is suggested ranging from 40°N to 60°N. Zhesi brachiopod fauna is an endemic fauna, containing more than 75% endemic species and self-grouped as a biogeographic province, termed Inner Mongolia Province. These characteristics indicate that this area was closed or semiclosed at that time. On the Jiamusi-Mongolia Block, the Herlen-Jiamusi Old-land as an obvious ＂continental barrier＂ hindered the northward migration of the Zhesi brachiopod fauna and the immigration of brachiopod species from other areas. The Tarim plate has collided with the Kazakhstan plate and the western part of South Tianshan-Beishan-Xar Moron Ocean has been closed. At the same time, the western margin of Jiamusi-Mongolia Block was joined with the Tarim plate. The Xar Moron Ocean in south of Jiamusi-Mongolia Block was wide e- nough and the ocean temperature rose gradually southward, so that it is not suitable for the cold-water brachiopods to survive and thrive on the northern margin of the North China plate. Thus, the ocean with large width and high temperature formed another natural barrier for the southward migration of the cold-water brachiopods.展开更多
The Paleozoic rocks are well exposed in the Taungnyo area and the main purpose of classification is taxonomic status of the invertebrate fossils and describing the systematic paleontology of brachiopod fossils from Ta...The Paleozoic rocks are well exposed in the Taungnyo area and the main purpose of classification is taxonomic status of the invertebrate fossils and describing the systematic paleontology of brachiopod fossils from Taungnyo Formation. Mainly distributed clastic sedimentary rocks of Taungnyo Formation (Early Carboniferous) and carbonate rocks of Moulmein Limestone Group (Permian to Middle Triassic) are well exposed in the Taungnyo area. In this study, mainly, a total of five species are recognized in the clastic sediments of Taungnyo Formation. Most brachiopods are generally found abundant and well preserved in the mudstone unit. Among them, most of the taxa have not been recorded previously. The brachiopods include: <em>Fimbrispirifer venustus</em>, <em>Ovetensispirifer ovetensium</em>, <em>Aullacella</em> sp., <em>Kayserellae emanuelensis</em>, and <em>Chonopectus</em> sp. All of the species are first recorded in Myanmar.展开更多
Affected by paleogeographic position, paleoclimatic condition and depositional environments, the increase of the Early-Mid Ordovician brachiopod diversity of South China commenced at the beginning of the Ordovician (e...Affected by paleogeographic position, paleoclimatic condition and depositional environments, the increase of the Early-Mid Ordovician brachiopod diversity of South China commenced at the beginning of the Ordovician (early Tremadoc), accelerated from the Tetra- graptus approximatus Biozone (base of Arenig), and reached its first acme in the Didymograptus eobifidus Biozone (mid early Arenig) when the number of brachiopod genera was over 7 times as great as that at the start of the Ordovician. This was the first radiation in the history of brachiopod macroevolution in South China, which occurred nearly 5 graptolitic biozones earlier than the global trend of the great Ordovician biodiversification (in the lower part of the Undulograptus austrodentatus Biozone). It is also characterized by (1) the origination or first occurrences of some major groups, such as the punctate dalmanelloids and the pseudopunctate stro- phomenoids including Plectambonitoidea (cardinal process simple or absent) and Stro- phomenoidea (cardinal process bilobed) in South China; (2) niche expansion, particularly in the first occupation of deeper water benthic regimes by the Euorthisina-Nocturnellia Association developed at Houping, Chengkou, northern Chongqing; and (3) the differentiation of brachiopod faunas under different environmental conditions. The gradual and increasing separation from Gondwana may have been one of the factors responsible for the radiation in South China.展开更多
The holotype of Yangtzedonta Yu, 1985 and its type species, Y. primitiva Yu, 1985, is an incomplete specimen of Xianfengella prima He et Yang, 1982. Therefore, based on the principle of priority, the names Yangtzedont...The holotype of Yangtzedonta Yu, 1985 and its type species, Y. primitiva Yu, 1985, is an incomplete specimen of Xianfengella prima He et Yang, 1982. Therefore, based on the principle of priority, the names Yangtzedonta and Y. primitiva Yu (1985) should be abandoned. The fact that ventral valve of Xianfengella is bilaterally symmetrical indicates that they are not the left valve of a bivalved mollusc, as originally proposed by Yu. At present, the oldest certain bivalve is Xianfengoconcha elliptica Zhang, which occurs in the Early Cambrian Qiongzhusi Stage in China. The oldest known rostroconch is Heraultipegma yunnanensis He et Yang, which first occurs in the third small shelly fossil assemblage zone of the Early Cambrian Meishucunian Stage. The oldest known monoplacophoran, Maikhanella pristinis (Jiang), first occurs in the first small shelly fossil assemblage zone (Meishucunian Stage). Evidence derived from analyses of shell morphology, mode of growth, histology, and stratigraphic occurrence suggests展开更多
文摘This paper deals with Jurassic brachiopods from North Tibet and South Qinghai and the stratigraphical subdivision there. Based on faunas and strata,a general outline of the palaeogeographical evolution has been traced out along the line of plate-tectonic movements . In this paper , 10 species of 8 genera are described , among which the species Lacunosella rhombica , Rntithyris vulgaris , Tanyothyris appositus , Apatecosia navicularis and Flabellothyris sp . nov . have been recognized as new .
基金This work was supported by the Natural Science Foundation of China （NSFC） （grant No. 40232024）；Chinese Geological Survey （grant No. 1212010611801） ；Ministry of Science and Technology of China （grant No. 2001CB711002）.
文摘The middle Permian Cryptospirifer fauna （brachiopod） has hitherto been found in more than 30 localities in the Yangtze Platform, South China. Examination of data from various localities shows that it occurs stratigraphically in three intervals in the range from the upper Kungurian to Wordian. In the Baoshan block in western Yunnan the fauna occurs in the basal part of the Daaozi Formation and is of possibly an early Wordian age. Outside China the Cryptospirifer fauna has been reported from central and northwest Iran and central Turkey, where the fauna may have an age around the Wordian／Capitanian boundary. Rapid global warming since the late Early Permian and possession of other suitable environmental factors such as proper substrate, clastic input and water depth enabled the Gondwana-derived Baoshan Block and related tectono-stratigraphic units in Iran and Turkey to host the Cryptospirifer fauna, a fauna evolved in the Yangtze Platform that is a type area of the Cathaysian province.
基金Supported by Project of Doctoral Program of Ministry Education (No.20060183023)
文摘By reasearch on geographic distribution, nine genera in bipolar distribution are selected from Permian brachiopods. These taxa originated from middle-high latitude areas in the boreal realm, of which five genera were derived from Late Carboniferous, and other four genera originated from Permian. They were all in bipolar distribution during some different stages in Permian. Specific diversity for each genus was high in the boreal realm, whereas in the Gondwana realm was very low. Perdurability was long in the boreal realm, and short in the Gondwana realm. It was the time when these nine genera came to their maximum diversity that these genera appeared in the Gondwana and formed bipolar distribution; while they also migrated to the low latitude from high latitude. This shows very close relationship between several main cooling events in Permian and the migration of genera from the boreal realm to the Gondwana reahn through the Tethys. Therefore, the cooling events might be the main drive which caused these cold-water-type brachiopods migrated to the Gondwana realm and being bipolar distribution. In this process, the planula tolerance to warm water would be another important factor.
基金supported by the National Natural Science Foundation of China(4070200541072017+8 种基金40830208)the 973 Project(2013CB835002)111 Project of China(P201102007)Swedish Research Council(VR 2009-43952012-1658 to LEH)ZZF acknowledges grants from the Fok Ying Tung Education Foundationthe China Scholarship Counciland the Ministry of Education of China(FANEDD200936NCET-11-1046)
文摘The Cambrian explosion was coined to describe the geologically sudden appearance of numerous bilaterian body plans(Phyla)around the Ediacaran-Cambrian transition,around 565-520million years ago.Many explanations and conjectures have been postulated in order to explain the pattern and duration of this explosive radiation of many different phyla of early metazoans.Here,we focus on the evolution of a phylum of marine suspension-feeding animals—the brachiopods,as exemplified by the exceptionally preserved taxa from the celebrated Chengjiang Konservat Lagerst(a|¨)tte(Yunnan,China).The abundant soft-bodied preservation at these fossil quarries gives us the only firm insights into what brachiopods looked like and how they functioned and lived when they first appeared on the Earth.Studies of Chengjiang brachiopods demonstrate that the early animals developed a remarkably varied organization of tissues and organs shortly after the onset of Cambrian explosion.In the marine suspension-feeding brachiopods,most importantly the tentaculate feeding structure of early brachiopods is already differentiated into two shapes of lophophore,anteriorly coiled(spiralled)and posteriorly arching tentacle crowns and the unique latter type was previously not documented from fossil and living brachiopods.Also unlike any known Recent brachiopod,all the known Cambrian brachiopods from Chengjiang have an open digestive tract that was disposed either as a Ushaped gut in linguliform and stem group brachiopods,or straight gut with a posterior anus in some calcareous-shelled stocks.Moreover,in contrast toliving lingulids,all the Cambrian brachiopods have an epibenthic lifestyle either cemented by a ventral valve or attached by variable pedicles to establish complex ecological community encompassing primary tierers and variable secondary tierers.It is therefore assumed that brachiopods were the first benthic metazoan that achieved their success in ecological stratification and tiering complexity by late Atdabanian.The setae are also important for the brachiopod suspension-feeding life style,and in the Chengjiang braehiopods they include two types cilia-like and spine-like setae.The mantle canals of different braehiopod species are also distinctly variable in arrangement,mainly disposed in pinnate,baeulate and peripheral conditions.Of these,the peripheral disposition of mantle canals is for the first time proposed here so as to differentiate from the bifurcate condition in recent lingulids in that the former is devoid of posteriorly extending main trunks of sinus,but possesses a diverging dorsal vascula media in dichotomy.
基金NSFC Innovation Research Group Program (Grant No. 40621002)MOE Innovative Research Team Program (Grant No. IRT0546)+1 种基金the National Natural Science Foundation of China (Grant Nos. 40472020, 40730209, 40802005 and 40872001)SINOPEC Project (Grant No. G0800-06-ZS-319)
文摘The abundance curves derived from area proportions of brachiopods and Girvanella in the thin sections from the Yangdi section, South China, exhibits complex relationships during the Late Devonian Frasnian-Famennian transition. The living activity of brachiopods such as grazing and borrowing did great damage to the growth of Girvanella. However, there was more to just a mere a survival competing relationship between them, Girvanella actually improved marine environments by oxygenating the dysoxic ambient sea-water through photosynthesis in the lower Kellwasser Horizon. Profited from this improvement brachiopods' abundance increased subsequently and suppressed Girvanella again. Nonetheless, without Girvanella's photosynthesis, brachiopods were wiped out by the farther anoxic environments in the upper Kellwasser Horizon. The complex relationships between Girvanella and brachiopods may be a key to unlocking the relationships between geomicrobes and metazoans in the geological overturn periods.
文摘That the contents and compositions of trace elements, especially REE in sedimentary rock and agustite originating from inarticulate brachiopods, conodont, etc. change in the vertical direction usually has a close relation with the stratigraphic boundary of important biologies. This paper systematically analyses REE and 16 trace elements such as U, Th, Sr, Ba, Co, Ni, Cr, V, Cu, Pb, Zn, Sc, Au, As in sedimentary rocks and the agustite on the standard stratified section of the Cambrian-Ordovician Boundary in Dayangcha, Huniiang, Jilin Province. Based on this, the authors investigate the REE distribution pattern and the law of the contents and compositions of trace elements changing, providing the geochemical evidence for building stratified sections of the Cambrian-Ordovician boundary and discussing sedimentary environments.
基金supported by State Key Laboratory of Palaeobiology and Stratigraphy (Nanjing Institute of Geology and Palaeontology,CAS) (Grant No.123115)the Fundamental Research Funds for the Central Universities"(Grant No.2010LKDZ01)
文摘The relationship between species diversity and ecosystem function is a hot topic in ecology and environics. This paper investi- gates the evolution of diversity of the late Middle Permian brachiopods community in Hechuan, Chongqing, China, and dis- cusses the relationship between species diversity and community productivity in terms of the geohistorical development. This paper shows that the species diversity is externalized by several indexes, and the relationship between diversity and productiv- ity is too complex to be described by a single assumption. The relationship between species diversity and community produc- tivity is restricted by environment and community evolution. When the community succeeds normally, the relationship be- tween species richness index, species diversity index, and species evenness index to productivity is in linear dependence rela- tion to each other, which is met with the third assumption. But, when the environment interference surpasses the beating capa- bility of the community, not only the community succession will be terminated and be replaced by another one, but also the relationship between species richness index, species diversity index, and species evenness index to productivity is also in- versed to negative correlation by the interference from environment. Only the relationship between ecological dominance and productivity is in linear dependence relation to each other and approximately met with the third assumption. It is illustrated that the assumption that the productivity is in linear dependence relation with diversity should be established on the presupposition that the community succession is normal.
基金supported by the Chinese Academy of Sciences (KZCX2-YW-Q05-01)the Ministry of Science and Technology of China (2006FY120300-5)the National Natural Science Foundation of China (40825006, 40972020), and the State Key Laboratory of Palaeobiology and Stratigraphy of NIGPAS
文摘A continuous Ordovician-Silurian boundary section from the upper Wufeng Formation through the Kuanyinchiao Formation to the lower Lungmachi Formation has been carefully measured and collected at Shuanghe of Changning, southern Sichuan Province. For the first time, the temporal changes of α- and β-diversities of the Hirnantia fauna have been discussed in great detail. The general trend of brachiopod diversity change, increasing upward, is consistent with the regional trend of the Yangtze Platform, which had been controlled by both intrinsic and extrinsic factors. However, the sudden drop of diversity for a short period in the upper Kuanyinchiao Formation might have been controlled by environmental factors rather than normal faunal turnover. Synecological analysis using numerical methods recognizes two brachiopod-dominated associations of the Hirnantia fauna, the Dalmanella-Kinnella Association and the Mirorthis Association, both living in an offshore, deeper water environment corresponding to BA3-upper BA4, particularly lower BA3.
基金the financial support of Russian FBR(No.18-05-00023A)。
文摘Information on latest early Olenekian(latest Smithian)ammonoids is available apparently from only seven regions of the world,including South Primorye.Latest Smithian evidences on this topic are recorded from the West SMID(abbreviation from the Russian name of the quarry:"Building Materials and Details"),East SMID and Golyj Cape areas in South Primorye.This provides additional information on systematic composition of latest Smithian ammonoid,as well as conodont and brachiopod assemblages from the recently identified Shimanskyites shimanskyi Zone,located between lower Olenekian Anasibirites nevolini Zone and upper Olenekian Tirolites subcassianus Zone.There are many common ammonoid species in the Shimanskyites shimanskyi Zone and the underlying Anasibirites nevolini Zone,e.g.,Prosphingitoides sp.,Arctoceras septentrionale(Diener),Churkites syskoi Zakharov et Shigeta,Submeekoceras?subhhydaspis(Kiparisova),Prionites markevichi Zakharov et Smyshlyaeva,?Anasibirites?simanenkoi Zakharov et Smyshlyaeva,Xenoceltites?subvariocostatus Zakharov et Smyshlyaeva,and Mianwaliites zimini Zakharov et Smyshlyaeva.The base of the Shimanskyites shimanskyi Zone,marked by a negativeδ13Corg excursion in the Kamenushka-2 Section by our previous study,coincides with the FO(first occurrence)of ammonoids Shimanskyites shimanskyi Zakharov et Smyshlyaeva and Glyptophiceras cf.sinuatum(Waagen)and conodont Hindeodella budurovi Buryi.This zone is characterized additionally by some fossils common for the overlying upper Olenekian Tirolites subcassianus Zone:ammonoids of the genus Kamenushkaites,brachiopods Bittnerihyris margaritovi(Bittner)and Lepismatina sp.and conodont?Neogondolella?(=?Borinella)jubata Sweet.The latest Smithian ammonoids recorded from the Shimanskyites shimanskyi Zone totally consist of 30 taxa belonging to 11 families(Sageceratidae,Ussuiriidae,Aspenitidae,Paranannitidae,Arctoceratidae,Proptychitidae,?Galfetitidae,Prionitidae,?Kashmiritidae,Xenoceltitidae and Palaeophyllitidae).The problems of global correlation of uppermost Smithian strata are also discussed.
文摘Abstract The alleged ＂holotype＂of the bivalve Yangtzedonta primitiva Yu.1985 figured by Qian （2001） is a broken and distorted specimen of the brachiopod Xianfengella prima He and Yang, 1982 and not the holotype of Y. primitiva. Qian contends that the oldest recognized monoplacophoran, Maikhanella pristinis （Jiang, 1980）, is neither a monoplacophoran nor the oldest molluscan fossil in the Meishucunian Stage of China. Furthermore, he considers that the oldest bivalve Xianfengoconcha eUiptica Zhang, 1980 is an inarticulate brachiopod, not a mollusc. WatsoneUa yunnanensis （He and Yang, 1982）, is associated with Yangtzedonta primitiva Yu but indicates no evolutionary relationship between the Classes Rostroconchia and Bivalvia in the Lower Cambrian Zhongyicun Member of the Yuhucun Formation. Qian＇s confusion in using non-molluscan fossils to discuss the early evolution of shelled molluscs also confuses the basic concepts of the respective groups.
文摘Data obtained on conodont distribution in the Permian-Triassic Sovetashen Section of Transcaucasia provide further limitations on the age of the carbon-isotopic anomalies discovered by Baud et al. (1989). The significance of Caucasian sections for working out the carbon-isotope standard for the Upper Permian and Lower Triassic (Induan) is shown. Original data on carbon-isotope composition of bivalve and brachiopod shells from Permian sediments of North-Eastern Russia (Omolon and Okhotsk areas) have been obtained, which may be used for their correlation.
文摘The stratotype region of the Ryazanian stage is located in the Oka River Basin near Ryazan, Central Russia. Since ammonites are very well studied here, we investigated other groups of macrofossils. We report a large number of bivalve genera: Arctica, Astarte, Buchia, Camptonectes, Chlamys, Ctenostreon, Entolium, Gomomya, Gresslya, Hartwellia, Lima, Meleagrinella, Modiolus, Oxytoma, and Pleuromya. The belemnites are represented by two cylindroteuthidid genera, Acroteuthis and Liobelus. In addition, brachiopods (Rhynchonellidae and Terebratulidae) and unidentifiable gastropod fragments have been revealed. The highest taxonomic diversity of macrofauna is observed in the Surites spasskensis ammonite Zone.
基金supported by the Doctoral Foundation of Ministry of Education of China (No. 20060183023)
文摘Tuvaella brachiopod fauna are distributed in an arc in three areas, including the Zeya-Hailar （海拉尔）-Shinejinst area, the Najramdal Uul-Kyzyl area, and the Barkol-Fuyun （富蕴） area. The Tuvaella fauna in the Zeya-Hailar-Shinejinst area are distributed in the northern margin of Jiamusi （佳木斯）-Mongolia block along the Mongolia-Okhotsk suture between the Siberia plate and the Jiamusi-Mongolia block but not appear in the corresponding Siberia plate. The Tuvaella fauna in the Najramdal Uul-Kyzyl area are distributed in the southwestern part of the Siberia plate as the accelerated fold belts during the Salairian-Caledonian periods, and those in the Barkol-Fuyun area are distributed in the northeastern margin of Kazakhstan plate. They are distributed along the Irtysb suture between the Siberia plate and the Kazakhstan plate. The Tuvaeila fauna became domestic fauna during the Wenlock and Pridoli （Middle-Late Silurian） and form a unique biogeographic province, i.e., the Mongolia-Okhotsk Province. This biogeographic province is sustained to the Mississippian （Carboniferous）, perhaps due to the semiclosed state of the Mongolia-Okhotsk Ocean. The northeastern margin （right now the southwestern margin） of Siberia plate, the northern margin of Jiamusi-Mongolia block, and the northeastern margin of Kazakhstan plate might be conjuncted in an arc region from Wenlock to Mississippian, along the southern margin of the Irtysh-Mid Mongolia-Okhotsk Ocean. This is coincident with the fact that the Siberia plate rotated 180° clockwise since the Mesozoic and located in the middle-high latitude during Devonian, and the coral reef limestone is widely developed in the Jiamusi- Mongolia block during the Early and Middle Devonian, which suggests that the block was positioning in middle-lower latitude at that time and that the Kazakhstan plate was also located in low latitude then.
基金granted by the National Natural Science Foundation of China(Grant No.41372019)the Doctoral Foundation of Ministry of Education of China(No.20110061110051)
文摘A comprehensive compilation and systematic analysis of known early and middle Permian brachiopod faunas shows that the early Permian brachiopod faunas comprise three realms,six regions,and eleven provinces,while those of the middle Permian comprise three realms,four regions,and eight provinces.A comparison and analysis of brachiopod faunal patterns reveal a coevolution between global brachiopod paleobiogeography and tectonopaleogeography during the early-middle Permian.Although temperature/latitude is the main factor controlling the formation of three realms,tectonopaleogeographic factors determine the temperature/latitude in which the continents were located.The'continental barrier'of Pangea,as a'central axis'continent,divided the three realms into six regions,which indicates that the formation of biogeographic regions was controlled mainly by the tectonopaleogeographic factors.The evolution of tectonopaleogeography was sometimes a long-term process,so that the biogeographic regions(or provinces)controlled by tectonopaleogeography displayed relative stability.Shifts in the nature of biogeographic provinces(e.g.,from cool water to warm water,and vice versa),extensions or narrowing of geographical ranges,and recombinations of some provinces were all related to regional tectonic evolution.The study of the coevolution between brachiopod paleobiogeography and tectonopaleogeography not only accounts for the formation mechanisms of brachiopod paleobiogeographic patterns during the early-middle Permian,but also provides evidences for the locations and configurations of oceans and plates(blocks)during this period.
基金supported by the Russian grant RFBR(No.14-05-00011-a)
文摘After the End-Permian mass extinction, ammonoids reached levels of taxonomic diver- sity higher than in the Changhsingian by the Dienerian Substage of the Induan. However, brachiopods exhibit a prolonged delay in recovery, and their taxonomic diversity had not recovered to Late Permian levels even by the Olenekian. The differential patterns of recovery between these two clades may reflect fundamental differences in physiology and behavior. Brachiopods were benthic organisms that were dependent on specific trophic sources, and their general reduction in size during the Early Triassic may have been a response to a relative paucity of food resources. In contrast, ammonoids were sluggish- nektic organisms that utilized a wider range of trophic sources and that suffered no comparable size decrease during the Early Triassic. Brachiopods may have been at a disadvantage also due to vulner- abilities associated with their larval stage, during which they had to locate a suitable substrate for set- tlement. In contrast, ammonoids had no larval stage and juveniles may have been dispersed widely into favorable habitats. These factors may account for differences in the relative success of ammonoids and brachiopods at high-latitude regions following the End-Permian mass extinction： ammonoids success- fully reeolonized the Boreal region during the Early Triassic whereas brachiopods did not.
基金The National Natural Science Foundation of China(Grant 40273014)has funded the project.
文摘Twelve paleocommunities dominated by benthic brachiopod are recognized in the Givetian-Frasnian stages of the Devonian in the Longmenshan area, southwestern China, in which two kinds of brachiopod community replacement are classified. One is the abrupt replacement, represented by abrupt alternation between the Leiorhynchus community and Zhonghuacoelia-Striatopugnax community in the Frasnian Tuqiaozi Formation. The other is the gradual one, developed in the Givetian Guanwushan Formation, which had been completed by the shift of the Independatrypa lemma-Uncinulus heterocostellis-Emanuella takwanensis community via the Sinospongophyllum irregulare-Pseudomicroplasma fongi community to the Clathrocoilona spissa-Hexagonaria composite reef community. According to analyses of the paleocommunities, either the abrupt or gradual paleocommunity replacement of the Middle-Upper Devonian in the Longmenshan area is suggested as a response to the 5th-order sea level fluctuation due to the replacements of the paleocommunities in a tracts-system of depositional sequence. It is supposed that changes of paleocommunity diversity, one of the results of paleocommunity replacement, are depended on the range and magnitude of sea level fluctuation, but there is not a linear relationship between them. Furthermore, a suggestion is proposed that the concept of paleocommunity succession seem to be abandoned in the paleocommunity analysis because it almost never be practiced to recover the information of community succession in the geological record at present.
基金Supported by Project of China Geological Survey (No.1212011120153-3)
文摘The Kungurian-Capitanian （Permian） Zhesi branchiopod fauna is mainly composed of cold-water typed taxa with high diversity and abundance. This fauna is similar with the coeval brachiopod faunas from Ti- man-Pechora, Svalbard, and Queen Elizabeth Islands of the Boreal Realm, with no real ＂warm-water＂ species. Zhesi brachiopod fauna is a cold-water fauna and should be assigned to the Boreal Realm. Considering the paleogeographic characteristics of this fauna and the basic rationale of paleobiogeographie provinces being controlled by latitude-temperate, and that the above areas were located at 50°N -70°N in the global paleoclimate reconstruction map compiled by Boucot et al. , the paleo-latitude of the southern margin of Jiamusi-Mongolia Block, where developed the Zhesi brachiopod fauna, is suggested ranging from 40°N to 60°N. Zhesi brachiopod fauna is an endemic fauna, containing more than 75% endemic species and self-grouped as a biogeographic province, termed Inner Mongolia Province. These characteristics indicate that this area was closed or semiclosed at that time. On the Jiamusi-Mongolia Block, the Herlen-Jiamusi Old-land as an obvious ＂continental barrier＂ hindered the northward migration of the Zhesi brachiopod fauna and the immigration of brachiopod species from other areas. The Tarim plate has collided with the Kazakhstan plate and the western part of South Tianshan-Beishan-Xar Moron Ocean has been closed. At the same time, the western margin of Jiamusi-Mongolia Block was joined with the Tarim plate. The Xar Moron Ocean in south of Jiamusi-Mongolia Block was wide e- nough and the ocean temperature rose gradually southward, so that it is not suitable for the cold-water brachiopods to survive and thrive on the northern margin of the North China plate. Thus, the ocean with large width and high temperature formed another natural barrier for the southward migration of the cold-water brachiopods.
文摘The Paleozoic rocks are well exposed in the Taungnyo area and the main purpose of classification is taxonomic status of the invertebrate fossils and describing the systematic paleontology of brachiopod fossils from Taungnyo Formation. Mainly distributed clastic sedimentary rocks of Taungnyo Formation (Early Carboniferous) and carbonate rocks of Moulmein Limestone Group (Permian to Middle Triassic) are well exposed in the Taungnyo area. In this study, mainly, a total of five species are recognized in the clastic sediments of Taungnyo Formation. Most brachiopods are generally found abundant and well preserved in the mudstone unit. Among them, most of the taxa have not been recorded previously. The brachiopods include: <em>Fimbrispirifer venustus</em>, <em>Ovetensispirifer ovetensium</em>, <em>Aullacella</em> sp., <em>Kayserellae emanuelensis</em>, and <em>Chonopectus</em> sp. All of the species are first recorded in Myanmar.
基金supported by MST(GrantNos.G2000077700 and DEA20020-4)NSF Grant No.40472 002)CAS(Gramt No.KZCX2-SW-129)of China
文摘Affected by paleogeographic position, paleoclimatic condition and depositional environments, the increase of the Early-Mid Ordovician brachiopod diversity of South China commenced at the beginning of the Ordovician (early Tremadoc), accelerated from the Tetra- graptus approximatus Biozone (base of Arenig), and reached its first acme in the Didymograptus eobifidus Biozone (mid early Arenig) when the number of brachiopod genera was over 7 times as great as that at the start of the Ordovician. This was the first radiation in the history of brachiopod macroevolution in South China, which occurred nearly 5 graptolitic biozones earlier than the global trend of the great Ordovician biodiversification (in the lower part of the Undulograptus austrodentatus Biozone). It is also characterized by (1) the origination or first occurrences of some major groups, such as the punctate dalmanelloids and the pseudopunctate stro- phomenoids including Plectambonitoidea (cardinal process simple or absent) and Stro- phomenoidea (cardinal process bilobed) in South China; (2) niche expansion, particularly in the first occupation of deeper water benthic regimes by the Euorthisina-Nocturnellia Association developed at Houping, Chengkou, northern Chongqing; and (3) the differentiation of brachiopod faunas under different environmental conditions. The gradual and increasing separation from Gondwana may have been one of the factors responsible for the radiation in South China.
基金This work was supported by the Major State Basic Research Project (Grant Nos. G2000077700 and 95-spe- cial-01-2-3) and the Knowledge Innovation Project of the CAS (GrantNo. KZCX2-116)
文摘The holotype of Yangtzedonta Yu, 1985 and its type species, Y. primitiva Yu, 1985, is an incomplete specimen of Xianfengella prima He et Yang, 1982. Therefore, based on the principle of priority, the names Yangtzedonta and Y. primitiva Yu (1985) should be abandoned. The fact that ventral valve of Xianfengella is bilaterally symmetrical indicates that they are not the left valve of a bivalved mollusc, as originally proposed by Yu. At present, the oldest certain bivalve is Xianfengoconcha elliptica Zhang, which occurs in the Early Cambrian Qiongzhusi Stage in China. The oldest known rostroconch is Heraultipegma yunnanensis He et Yang, which first occurs in the third small shelly fossil assemblage zone of the Early Cambrian Meishucunian Stage. The oldest known monoplacophoran, Maikhanella pristinis (Jiang), first occurs in the first small shelly fossil assemblage zone (Meishucunian Stage). Evidence derived from analyses of shell morphology, mode of growth, histology, and stratigraphic occurrence suggests
