Morphological study on the Devonian zosterophyll Serrulacaulis Hueber and Banks: New materials and emendation

The generic diagnosis of the Mid–Late Devonian zosterophyll Serrulacaulis Hueber and Banks is emended based on morphological study on specimens from New York State (USA), Belgium and Venezuela, and new materials of S. spineus n. sp. from the Middle Devonian Hujiersite Formation of Xinjiang, Northwest China. The new species S. spineus has bilateral obdeltoid emergences and sparsely arranged spines on the axis surface, alternately arranged, reniform sporangia with unequal valves. A variety of the axial emergence appearances of Serrulacaulis is noted, which further indicates easily recognizable features of the genus.     

First fossils of Zygogynum from the Middle Miocene of Central Yunnan,Southwest China,and their palaeobiogeographic significance

The collision of Gondwana and Laurasia effected plant exchanges between the two continents and thus affected the evolution of the flora of Yunnan, Southwest China. Consequently, the plant diversity in Yunnan has been enriched such that it has attracted the attention of botanical researchers. In this paper, we describe winteraceous fossil leaves collected from the Middle Miocene in Central Yunnan. Compared with the leaves of today’s plants, they share cuticular features and leaf morphological characters with Zygogynum Baillon (Winteraceae); the fossil plant is designated as a new species, Zygogynum poratus n. sp. Liang and Zhou. Based on its historical and recent distribution, the genus probably had migrated into Yunnan from Gondwana during or before the Middle Miocene, spreading beyond its current geographic range.     

Ginkgoalean woods from the Jurassic of Argentina: Taxonomic considerations and palaeogeographical distribution

A specimen of Baieroxylon rocablanquense nov. sp. from the Roca Blanca Formation (Early Jurassic), and a specimen of Ginkgomyeloxylon tanzanii Giraud and Hankel from the La Matilde Formation (Middle Jurassic), both located in the Santa Cruz province, Argentina, are described in detail. Identification of the morphogenus Baieroxylon is based upon secondary xylem characteristics (cross-field tracheid pitting, cross-fields and ray characters), while identification of Ginkgomyeloxylon is based upon pith, primary xylem and secondary xylem features. A synthesis of Ginkgoalean woods is presented, which combines diagnostic anatomical evidence with data related to stratigraphic and paleogeographical distributions. Based on the results of this analysis, a key for genus-level identification is provided and a new genus, Ginkgopitys, is proposed. These results are used to elucidate global patterns of historical distribution over the course of geological time. In Gondwana, a great diversity of “mixed-type” woods was present during the Mesozoic, especially during the Late Triassic. In contrast, in Laurasia a lower diversity of the mixed-type is recorded for the Paleozoic and Mesozoic, with increases in “abietinoid-type” wood – similar to extant Ginkgo – taking place at the beginning of the Cretaceous. During the Jurassic and Early Cretaceous in both Laurasia and Gondwana, mixed-type and abietinoid-type woods co-existed, illustrating that important evolutionary changes in wood anatomy occurred during the Mesozoic (Jurassic-Cretaceous).     

Cyclotosaurus cf. PosthumusFraas (Capitosauridae,Stereospondyli) from the Huai Hin Lat Formation (Upper Triassic), Northeastern Thailand: With a note on capitosaurid biogeography

Part of a large capitosaurid skull, similar to that of Cyclotosaurus posthumus from the Upper Triassic of Germany, has been discovered in the upper part of the Huai Hin Lat Formation near Chulabhorn (Nam Phrom) Dam. This discovery is consistent with the presumed Norian age of this formation. Although the phylogeny of the Capitosauridae is still unclear, the group of Upper Triassic Cyclotosaurus species to which C. posthumus belongs is monophyletic and seems to be known only from Laurasia or Northwestern Gondwana (Morocco). The occurrence of C. cf. posthumus in Thailand is consistent with the hypothesis previously put forward, that this part of Southeast Asia was bound to Laurasia in Mesozoic times.     

Middle–Late Ordovician chitinozoans from Songliang of Qiaojia,western South China,and their biostratigraphic implications

Ordovician chitinozoans are as yet inadequately documented from the western Yangtze Platform, South China. Here we present a systematic study on chitinozoans from a Middle–Upper Ordovician succession at Songliang of Qiaojia, northestern Yunnan, southwestern China. Altogether 34 species of 12 genera are identified from the upper Hungshihyen and the Huadan formations. The top of the Hungshihyen Formation yields typical Early and Middle Ordovician forms, for instance, Lagenochitina obeligis and Belonechitina chenjiawuensis, with the latter only known from the lower Darriwilian in South China, thus suggesting an early Darriwilian age for this interval. The chitinozoans recovered from the Huadan Formation include Lagenochitina prussica and Spinachitina fossensis, both are mainly confined in Katian and sometimes ranging into younger strata. This indicates an age younger than the middle to late Darriwilian previously determined for the Huadan Formation. However, conflicts exist in age assignment of the Huadan Formation based on chitinozoan and other evidence, and further work is required.     

Late Darriwilian–early Katian (Ordovician) ostracods of northeastern Yunnan,Southwest China

Ordovician silicified ostracods of the western Yangtze Platform, South China, are documented for the first time from the Huadan Formation of Qiaojia County, northeastern Yunnan Province, Southwest China. Twenty-one species of 17 genera are identified with new taxa including Vendona spinifera n. sp. and Nikitinella songliangensis n. sp. These two species, together with Medianella gigantea are the most common constituents of the fauna. Faunal comparison shows close connections between South China, Baltica, the Argentine Precordillera, Kazakhstan, Tarim, and Sibumasu during this time interval. This fauna is considered to be related to a nearshore carbonate environment, and biostratigraphical analysis of it supports a late Darriwilian to early Katian age for the Huadan Formation.     

Llandovery sporomorphs and graptolites from the Manbo Formation,the Mojiang County,Yunnan, China

Llandovery sporomorphs and graptolites have been recovered from the Manbo Formation, Mojiang area, western Yunnan, China, which belonged to the Indo-China Palaeoplate in the Palaeozoic. The graptolite fauna, including 8 genera and 12 species, is considered Mid Telychian, Llandovery in geological age, confirming the existence of Llandovery rocks in this region. The Silurian stratigraphical sequence of this area is reconsidered as in the ascending order: Manbo Formation (Llandovery–early Wenlock), Shuiqing Formation (late Wenlock–Ludlow) and unnamed formation (Pridoli?). The sporomorph assemblage from the Manbo Formation includes seven species in five genera. The dominant members of this assemblage are Tetrahedraletes medinensis and Laevolancis chibrikovae. Based on the low diversity and low abundance, the geological age of this assemblage is considered to be approximately the Telychian, Llandovery. The parent plants of sporomorphs probably inhabited the landmass near Mojiang area, these sporomorph-producing plants probably included bryophyte-like land plants and primitive vascular land plants. The sporomorph evidence shows that the South China and Indo-China palaeoplates may have been in close proximity (maybe with some continental bridges linking them) to each other at least in the Llandovery. They were also closely related with Gondwanaland in the Llandovery.     

New freshwater mussels (Bivalvia,Unionida) with potential trigonioidid and hyriid affinities from the Early Cretaceous of Brazil

Two new taxa of freshwater mussels (Bivalvia: Unionida) from the Aptian Crato Formation of the Araripe Basin, NE Brazil, are described. The fossil bivalves are confined to 30- to 130-cm-thick bioturbated mudstones overlying the fossil-rich laminated limestones of the Crato Formation Konservat-Lagerstätte. Individuals are often preserved with closed or splayed articulated valves, some of them potentially in life position, forming an autochthonous to parautochthonous assemblage. Monginellopsis bellaradiata nov. gen., nov. sp. shares key characters with the Trigonioidoidea: (i) the anterior pedal retractor muscle scar is clearly separated from the anterior adductor muscle scar; (ii) the shell has fold-like radial ribs on the posterior half; (iii) a right valve anterior tooth has a striated facet. Araripenaia elliptica nov. gen., nov. sp. is the most abundant and widely distributed unionid of the Crato Formation. Its ornament of anterior inverted V-shaped riblets, and central and posterior radial and sub-radial riblets resembles modern and fossil Hyriidae from the Americas, but also Trigonioidoidea from Eurasia. Its dentition of two smooth anterior pseudocardinals and two smooth posterior laterals in each valve provides no further clues for systematic assignment; muscle scars are not preserved. Assignment to the Hyriidae would make Araripenaia the oldest member of this family known from South America. Moreover, this bivalve assemblage of trigonioidoidids, hyriids, and previously reported silesunionoids suggests palaeobiogeographic links to other areas in both Gondwana and Laurasia.     

Reanalysis of Wupus agilis (Early Cretaceous) of Chongqing,China as a Large Avian Trace: Differentiating between Large Bird and Small Non-Avian Theropod Tracks

Trace fossils provide the only records of Early Cretaceous birds from many parts of the world. The identification of traces from large avian track-makers is made difficult given their overall similarity in size and tridactyly in comparison with traces of small non-avian theropods. Reanalysis of Wupus agilis from the Early Cretaceous (Aptian-Albian) Jiaguan Formation, one of a small but growing number of known avian-pterosaur track assemblages, of southeast China determines that these are the traces of a large avian track-maker, analogous to extant herons. Wupus, originally identified as the trace of a small non-avian theropod track-maker, is therefore similar in both footprint and trackway characteristics to the Early Cretaceous (Albian) large avian trace Limiavipes curriei from western Canada, and Wupus is reassigned to the ichnofamily Limiavipedidae. The reanalysis of Wupus reveals that it and Limiavipes are distinct from similar traces of small to medium-sized non-avian theropods (Irenichnites, Columbosauripus, Magnoavipes) based on their relatively large footprint length to pace length ratio and higher mean footprint splay, and that Wupus shares enough characters with Limiavipes to be reassigned to the ichnofamily Limiavipedidae. The ability to discern traces of large avians from those of small non-avian theropods provides more data on the diversity of Early Cretaceous birds. This analysis reveals that, despite the current lack of body fossils, large wading birds were globally distributed in both Laurasia and Gondwana during the Early Cretaceous.     

Early Triassic bivalves from the Feixianguan Formation in Xingyi,Guizhou and the Ximatang Formation in Qiubei,Yunnan (southern China)

Based on newly collected materials from the Lower Triassic Feixianguan Formation of Xiongwu section in Xingyi, Guizhou and the Ximatang Formation of Ximatang section in Qiubei, Yunnan, southern China, nine species belonging to seven genera are described. Two bivalve assemblages are recognized and regionally correlated in South China. The bivalve assemblage from the Feixianguan Formation of Xiongwu exhibits a higher diversity including seven species belonging to seven genera: Claraia griesbachi, Leptochondria virgalensis, Entolium (Entolium) microtis, Towapteria scythicum, Bakevillia exporrecta, Bositra sp., and Unionites? fassaensis. In contrast, the bivalve assemblage from the Ximatang Formation of Ximatang has a much lower diversity, consisting of only two species, i.e., Claraia griesbachi and Claraia radialis. Additionally, C. griesbachi and C. radialis, as the most common species of Claraia in the Early Triassic, are revised.     

沙顿蕨——曲柄沙顿蕨（新种）在我国的发现

对采自新疆西准噶尔和丰县中泥盆统（相当于艾菲尔阶）呼吉尔斯特组下部的沙顿蕨一新种——曲柄沙顿蕨（Ｓａｗ ｄｏｎｉａ ｃｕｒｓｔｉｐａ ｓｐ．ｎｏｖ．）进行了一些形态学方面的描述,并与已知的沙顿蕨属（Ｓａｗ ｄｏｎｉａ）的两个种Ｓ．ｏｒｎａｔａ 和Ｓ．ａｃａｎｔｈｏｔｈｅｃａ 作了对比。研究表明,Ｓ．ｃｕｒｓｔｉｐａ 在孢子囊柄长度和孢子囊着生方式等方面与沙顿蕨属的两个种有明显的差异     

Lower Devonian vertebrates, arthropods and brachiopods from northern Vietnam

Additional vertebrates and ostracods from the bituminous shale of the Khao Loc Formation at Tong Vai, Ha Giang Province, northern Vietnam, corroborate its correlation with the upper part of the Xishancun (Xiaxishancun) Formation and the lower part of the Xitun and Lianhuashan formations of South China, and its Middle to Late Lochkovian age. The variations in morphology and ornamentation of the galeaspid Polybranchiaspis liaojaoshanensis from Tong Vai are discussed and regarded as possibly size and growth-related. A new acanthothoracid placoderm with a very deep dorsal process is described from Tong Vai and the specific distinction between the antiarchs Minicrania lissa from Tong Vai and M. lirouyii from Yunnan is supported by additional characters. Petalichthyid placoderms are recorded from this locality for the first time, and the skull of a juvenile youngolepidid sarcopterygian is described. Eurypterid fragments and a phyllocarid crustacean are also recorded from the Khao Loc Formation. A new species of the chonetid brachiopod genus Tulynetes, endemic to northern Vietnam, is described from the Pragian Mia Le Formation at Cu Le, Bac Kan Province, a new locality which yields a large diversity of taxa with outstanding preservation.     

Lower Emsian biostratigraphy and event stratigraphy of Ha Giang Province,northern Vietnam

A new species of rugose coral, Sanidophyllum dubium n. sp., and the typical Emsian (Early Devonian) rugose coral Xystriphylloides nobilis are described from the Mia Le Formation in northern Vietnam. The lower Emsian index conodonts ranging from the Polygnathus excavatus zone to the P. nothoperbonus zone are illustrated. The biostratigraphic correlation between northern Vietnam and South China shows that the Mia Le Formation in northern Vietnam is early Emsian in age, and its upper part can be correlated with the lower part of the Shizhou Member of the Yukiang Formation in Liujing, Guangxi and its equivalents in South China. Based on the study of the lower Emsian biostratigraphic sequence, the disappearance of Xystriphylloides nobilis fauna in the overlying bed of the uppermost Mia Le Formation and the extinction of the “tonkinensis fauna” (sensu lato) in the interval between the basal Si Phai Formation and the uppermost Mia Le Formation demonstrate the influence of the Yujiang Event in northern Vietnam.     

Age constraints of the Hungshihyen Formation (Early to Middle Ordovician) on the western margin of the Yangtze Platform,South China: New insights from chitinozoans

The Hungshihyen Formation represents the Lower to Middle Ordovician near-shore siliciclastic deposits on the western margin of the Yangtze Platform, South China. However, its age is still debated, largely because of insufficient studies. Here we documented the Bursachitina maotaiensis–B. qianbeiensis chitinozoan assemblage from the lower part of the Hungshihyen Formation at Songliang, Qiaojia County, eastern Yunnan Province. This assemblage is remarkably similar to an assemblage that roughly correlates to the middle part of the Corymobograptus deflexus graptolite Biozone in northern Guizhou Province, indicating that the Hungshihyen Formation at Songliang is probably of late Floian age and may extend into the early Dapingian. Additionally, a revision on the chitinozoans previously documented from the strata assigned to the same formation in the Wuding area was made according to the latest classification. The revision allows the recognition of the Euconochitina symmetrica–Eremochitina brevis assemblage, and therefore suggests a late Tremadocian age for this interval based on regional and global chitinozoan biostratigraphic correlations. Considering also its lithologic succession, we argue that the chitinozoan-bearing strata in the Wuding area previously assigned to the Hungshihyen Formation correspond most likely to the uppermost part of the underlying Tangchi Formation or the lowermost part of the Hungshihyen Formation. The base of the Hungshihyen Formation appears therefore to be diachronous in eastern Yunnan Province.     

A latest Ordovician Hirnantia brachiopod fauna from western Yunnan,Southwest China and its paleobiogeographic significance

A new, high-diversity, latest Ordovician brachiopod fauna of nearly 800 brachiopod specimens was collected from the Wanyaoshu Formation (Hirnantian) in the Shaodihe section, Mangshi City, western Yunnan, Southwest China. Altogether 22 genera and two undetermined taxa were identified; dominant are Aegiromena, Anisopleurella, Fardenia, Dalmanella, Hirnantia and Hindella, less common, Paromalomena, Leptaena, Eostropheodonta, Cliftonia, Kinnella, Templeella and Plectothyrella, together with some rare Petrocrania, Xenocrania, Pseudopholidops, Palaeoleptostrophia, Skenidioides, Giraldibella, Draborthis, Dolerorthis and Toxorthis. This is one of the most diverse typical Hirnantia faunas, associated with the Kosov Province. The paleobiogeographic relationships between western Yunnan (Southwest China), Myanmar, Yichang (Central China), Tibet (Southwest China) and Kazakhstan are clarified using Network Analysis and NMDS. The fauna studied is most similar to that of Myanmar; both resided on the Sibumasu terrane. However, the recalculated network diagram, when including the data of Hirnantia fauna from the Prague Basin, indicates that the latter is more closely linked to that of western Yunnan, a testament to the very weak brachiopod provincialism during the Hirnantian, mainly due to the influence of dominant cosmopolitan taxa. Some species of the fauna display significant population variation. Two of the dominant taxa, Aegiromena and Anisopleurella are systematically described, whereas the other two common taxa, Fardenia and Hirnantia are measured and their outlines and internal structures analyzed.     

Report of Sawdonia in China--Sawdonia curstipa sp. nov.

A new species, Sawdonia curstipa was found in the Hujiersite Formation of the Middle Devonian (Eifelian) from Hefeng County of Xinjiang Autonomous Region, China. Morphologically, this species was different from S. ornata and S. acanthotheca in stalk length, pattern of sporangial insertion, etc. Both axis and emergence possessed oblong epidermal cells.     

Trace fossils from lower Cambrian Hongjingshao Formation,Yunnan, China: Taxonomy,palaeoecology, palaeoenvironment

The Hongjingshao Formation (Cambrian Series 2, Stage 3) yields abundant, complex trace fossils that have not been systematically investigated up till now. Our detailed ichnological study of the traces from this formation in Malong area, Yunnan, China, recognizes four groups: (1) simple horizontal or sub-horizontal burrows; (2) complex branched burrow systems; (3) arthropod trails and; (4) simple vertical burrows belonging to the Cruziana ichnofacies. A trophic web is reconstructed for the community in Hongjingshao Formation based on both trace and body fossils. The ichnological and sedimentological features of the formation indicate an intertidal setting. The trace fossil assemblage demonstrates that Early Cambrian organisms were able to colonize very shallow marine environments, which further supports the landward expansion of the Early Cambrian ecosystems.     

New Permian tetrapod footprints and macroflora from Turkey (Çakraz Formation, northwestern Anatolia): Biostratigraphic and palaeoenvironmental implications

New tetrapod footprints belonging to the ichnogenus Hyloidichnus have been discovered in Turkey for the first time, in the lower part of the Çakraz Formation (Northwestern Anatolia) and together with macrofloral imprints of Annularia and Stigmaria. These discoveries confirm the Permian age of the fossiliferous red beds in which the coniferophyte Walchia was previously recorded. Based on the stratigraphic range of Annularia, Stigmaria and Hyloidichnus known elsewhere, a Cisuralian age is proposed for these beds. These new ichno- and macrofloral remains, together with the sedimentological data (mudcracks, rain drops) suggest the presence of captorhinid reptiles living in a palustrine floodplain environment, and under a warm, seasonal climate alternating between humid and relatively long dry seasons. These climatic conditions may have permitted the migration of these captorhinids through Laurasia during the Permian.     

Reinvestigation of conchostracans (Crustacea: Branchiopoda) from the Permian–Triassic transition in Southwest China

Sedimentary deposits of the Permian–Triassic transition are well-exposed in numerous outcrops of South China. Depending on the palaeogeographic positions of the sections, their lithofacies vary from fully marine, shallow marine, lagoonal, lacustrine, and fluvial to alluvial. In the present study, conchostracans (Crustacea: Branchiopoda) were newly collected from the continental deposits of the Kayitou and Jialingjiang formations around the Kangdian Highland elevated by the Emeishan Basalt in the southern Sichuan, western Guizhou, and northeastern Yunnan provinces. The conchostracan fauna of the Kayitou Formation is composed of Pseudestheria chatangensis, Euestheria fuyuanensis, and Euestheria sp. aff. E. gutta. These species occur in varying lithofacies types of different sections. In particular, the late Permian Pseudestheria chatangensis occurs in grey siltstones interbedded with pebbly sandstones, which are interpreted as lacustrine deposits. Euestheria fuyuanensis and Euestheria sp. aff. E. gutta were obtained from yellowish to greenish–grey clay- and siltstones, interpreted as coastal plain deposits. In comparison to other regions, occurrences of Euestheria gutta are indicative of an early Induan to Olenekian (Early Triassic) age. The fossil record of Euestheria fuyuanensis is so far restricted to a few occurrences in the Kayitou Formation of Southwest China and, therefore, using this species for long-distance biostratigraphic correlation requires further investigation. The distribution of late Permian pseudestheriid and Early Triassic euestheriid species in the respective sections possibly depends on the local lithofacies and, therefore, a diachronous age of the Kayitou Formation within the study area can be assumed. Additionally, Magniestheria sp. aff. M. mangaliensis and Magniestheria sp. aff. M. subcircularis were recorded in the Jialingjiang Formation, which represents a lithostratigraphic unit considered as late Early Triassic (Olenekian). Further investigations of both taxonomy and the real stratigraphic ranges of the conchostracan species as well as cross-correlations with other age data are recommended, in order to better constrain the position of the Permian–Triassic boundary and the specific timing of the terrestrial end-Permian mass extinction in continental deposits of Southwest China.     

New data on duck-billed dinosaurs (Ornithischia, Hadrosauridae) from the upper cretaceous of Tajikistan

Duck-billed dinosaur remains (Hadrosauridae) from the Yalovach Formation (Lower Santonian) of the Isfara 2 and Kansai localities (northern Tajikistan) are described. Most of them belong to a flat-headed hadrosaurid which is distinguished from all other representatives of the family by the absence on the frontals of a facet for the nasals. In this feature, the Tajikistan hadrosaurid is similar to Bactrosaurus johnsoni from the Iren Dabasu Formation of China, which shows the minimum contact of the frontals and nasals; and in the wide prefrontal, it resembles Aralosaurus tuberiferus from the Bostobinskaya Formation in Kazakhstan. The theropod Troodon isfarensis Nessov, 1995 from Isfara 2 is described based on a hadrosaurid prefrontal.