Palaeozoic stromatoporoid futures:A discussion of their taxonomy,mineralogy and applications in palaeoecology and palaeoenvironmental analysis

Palaeozoic stromatoporoids are calcified sponges common between Middle Ordovician and Late Devonian times in reefs and related facies.Taxonomic work is well known,but controversial because of conflict between classification schemes based on the calcareous skeleton versus spicules(which are almost completely lacking in Palaeozoic stromatoporoids);however,lower-level taxonomy(at genus-level) of the calcareous skeleton is considered reliable to be applied in palaeobiological study.Knowledge of stromatoporoid ecology is poorly developed,such that comprehensive information is available for only a few case studies,in some Silurian and Devonian examples.Thus an overall understanding of stromatoporoid responses to environmental conditions has not yet been achieved,although stromatoporoids were likely able to deal with fine grained sediment where they mostly occur.Many stromatoporoid genera have only certain growth forms,so future focus on the use of low-level taxonomy in ecological studies,by comprehensive sampling in high-resolution studies,may establish the relationships between stromatoporoids and their environments.Intergrown organisms and growth banding in stromatoporoids are aspects that have great potential in such work.Mineralogy of stromatoporoids remains poorly understood.Regardless of their apparent state of preservation(ranging from apparently well-preserved to complete loss of calcareous skeleton features) all stromatoporoids are in fact substantially recrystallized.They underwent a peculiar diagenesis,whereby the calcareous skeleton and gallery cements of all stromatoporoids are overprinted by irregular elongated calcite crystals arranged normal to the growth laminations,most clearly visible in cross-polarized light.Stromatoporoids cooccur with mollusc shells that are always either fully recrystallized or dissolved(present as internal and external moulds);this difference means that while molluscs are likely under-represented in the fossil record,stromatoproids are not,providing confidence for palaeoecological work on their assemblages.Stromatoporoids lack characters which would readily classify them as being originally aragonite or low-Mg calcite;they may have been high-Mg calcite but the evidence is circumstantial.Their peculiar diagenetic fabric also has implications for the debate about the relationship between stromatoporoids and the concept of aragonite/calcite seas,which requires more work.

A Century of Spinosaurs-A Review and Revision of the Spinosauridae with Comments on Their Ecology

The spinosaurids represent an enigmatic and highly unusual form of large tetanuran theropods that were first identified in 1915. A recent flurry of discoveries and taxonomic revisions of this important and interesting clade has added greatly to our knowledge. Spinosaur body fossils are however generally rare and most species are known from only limited skeletal remains. Their unusual anatomical adaptations to the skull, limbs and axial column all differ from other large theropods and point to an unusual ecological niche and a lifestyle intimately linked to water.

Viséan Fossil Plants from the Jiujialu Formation in Central Guizhou Province: Implications for Age of Bauxite and Palaeoenvironment

Fossil plants from the carbonaceous shale of upper part of the Lower Carboniferous Jiujialu Formation in Lindai bauxite deposit fill a gap regarding the distribution of Early Carboniferous flora in Central Guizhou Province.Here the Lindai plant assemblage is systematically described,and its composition and geological age are discussed.Research demonstrates that 9 species in 6 genera of the fossil plants are discovered in this study,and they belong to lycopsids,sphenopsids and ferns,respectively.Based on the analysis of the floral composition,the geological age of the Lindai plant assemblage belongs to the Early Carboniferous Viséan.The discovery of Lindai plant assemblage not only provides a new fossil evidence to restrict the age of bauxite deposits in Lower Carboniferous Jiujialu Formation of Central Guizhou Province,but also has great significance to further research the palaeoecological setting and floral evolution during the Early Carboniferous.

Paleoecology of Oligocarpia gothanii Halle from the Middle Permian of Southeastern Shanxi,North China

Fossil ferns are abundant and diverse in the Permian Cathaysian Flora of Shanxi, North China. Although plants assemblages of the Carboniferous and Permian have been extensively investigated, their palaeoecology and especially the paleoecology of ferns has not been studied in detail. Recent reinvestigation of Oligocarpia gothanii has revealed its growth habit and cloning reproduction strategy, but most previous studies lack integrated sedimentological and taphonomic data. In this study, new materials of O. gothanii have been collected from a floodplain setting in the middle Permian Lower Shihhotse Formation of southeastern Shanxi. These plant fossils were found in a lenticular claystone associated with rooting structures. They are characterized by aphlebia at the base of the penultimate rachis. Sedimentological, taphonomic and morphological analyses were conducted to understand the growth habit and ecology of the fern. The result indicates that the Oligocarpia gothanii had a prostrate, ground cover growth habit, and was dominant in pioneer floras that colonized disturbed floodplains.

Reconstruction of the Vegetation and Environment during Different Climatic and Sociotechnical Conditions of the Last 3000 Years in Southwestern Hungary

Sedimentary basins such as Lake Baláta in Southwestern Hungary provide information about the development of lake-bog systems, the climate change through time and the environment of the surrounding area. The present study provides combined palynological, anthracological and macrobotanical data regarding climatic, vegetation and hydrological changes of a protected area for the last 3000 years. Lake Baláta is a sedimentary basin developed in a wind-blown yardang system in Southwestern Hungary. Due to its deeper location and the higher groundwater-level, the boggy lake functioned as a sediment catch. Geological drilling with an auger head drill provided an undisturbed sediment core. During the laboratory analysis different methods, such as sedimentological, geochemical, macrofossil, pollen and charcoal analysis were applied. The different stages and the evolution of the lake-bog system and the vegetation around the lake could be reconstructed and human impact was detected for the last 3000 years. Human impact and the transformation of vegetation was detected from the Early Iron Age (900/800 BC). Human impact reached its maximum during the 10th and 12th centuries when extent plant cultivation and grazing field zones were created. Climate change, increasing precipitation and consequently forest regeneration started in the 13th and 14th centuries. Parallel to this human impact decreased in the study area that indicates the reduction of the population and agrarian activity. Later at the beginning of the 15th century human impact increased again and remained significant until to the 16th century.

Priapulid worms from the Cambrian of China shed light on reproduction in early animals

In the recent years,exceptional fossil sites have revealed astonishing details on the anatomy,lifestyles and behaviour of Cambrian animals but surprisingly,very little is known about one of their most vital features,reproduction.We describe here in situ eggs(clusters of 3 to 30 oocytes)in the tube-dwelling priapulid worm Paraselkirkia sinica from the Cambrian Stage 3 Xiaoshiba Lagerstätte(ca.514 Ma,South China).These oocytes were accommodated within paired tubular ovaries located in the posterior half of the primary body cavity as in modern meiobenthic priapulid worms,thus indicating that the general organization of female tubular gonads in priapulid worms has remained virtually unchanged for half a billion years.Our findings provide for the first time,key information on the reproductive organs and strategies of early ecdysozoans,a huge animal clade that dominated Cambrian marine ecosystems and accounts for a large part of today’s biodiversity(e.g.arthropods).Moreover,we also emphasize the critical role of ecology on the reproductive strategies and lifestyles of both modern and Cambrian worms.

Elemental and Isotopic Signatures in the Sediments Influenced by Seal Excrement on Antarctic Fildes Peninsula and Their Potential Paleoecological Applications

The elemental and isotopic signatures in the sediments influenced by seal excrement on Antarctic Fildes Peninsula are examined for their potential palaeoecologlcal applications. The seal hair abundance in sediments exhibits remarkable fluctuation versus depth, indicating similar changes in historical populations of the seals visiting the marine terrace. The combination of δ^13 C, total organic carbon concentration （TOC）, total nitrogen concentration （TN） and atomic C/N ratio shows that the organic matters in sediments with numerous seal hairs have a marine origin and are predominantly derived from seal excrements. The large δ15 N values in sediments are attributed to trophic enrichment and NH3 vollatilization processes. The large variations in the δ^15 N values and the negative correlation between the δ15 N values and the seal hair abundances seem to be the results of changes in the paleoclimates and the volatilization rates of the ammonia produced in the seal excrements. The 87 Sr/86 Sr ratios in the acid-soluble fraction of sediments are interpreted as a mixture of the ones from the seal excrements （30%-50%） and the chemically weathered local bedrocks （70%-50%）. The calculated proportion of seal-derived Sr based on the ^87 Sr/^86 Sr ratios has a significant correlation with seal hair abundances in sediments. These results suggest that δ15 N values and the ^87 Sr/^86 Sr ratios in the acid-soluble fraction of sediments were influenced by seal excrements, similar to seal halt numbers, and thus can potentially be used to estimate the historical seal population in the Antarctic region.

Fossil middle triassic “sea cows” – placodont reptiles as macroalgae feeders along the north-western Tethys coastline with Pangaea and in the Germanic basin

The descriptions of fossil Triassic marine pla- codonts as durophagous reptiles are revised through comparisons with the sirenia and basal proboscidean mammal and palaeoenvironment analyses. The jaws of placodonts are conver- gent with those of Halitherium/Dugong or Mo- eritherium in their general function. Whereas Halitherium possessed a horny oral pad and counterpart and a special rasp-like tongue to grind seagrass, as does the modern Dugong, placodonts had large teeth that covered their jaws to form a similar grinding pad. The sirenia also lost their anterior teeth during many Millions of years and built a horny pad instead and specialized tongue to fed mainly on seagrass, whereas placodonts had only macroalgae availa- ble. Indirect evidence for Triassic macroalgae is provided by benthic palaeocommunities from different layers and extended European regions in the Germanic Basin. Studies of tooth wear stages for Placodus indicate that anterior teeth may have been used in a similar manner to the procumbent front teeth of modern Dugong. Paraplacodus and Placodus seem to have used these teeth as spatulas to dig out seaplants. Cyamodus and other placodonts such as Placochelys had smaller or reduced anterior teeth. The scarcity of highly worn palatine or maxillary and lower jaw dentary Placodus or Cyamodus teeth (less then 0.5%) suggests that they had a relatively soft diet. The seaplants would only have been squeezed in a similar feeding strategy to that of modern Dugong feeding on seagrass without jaw rotation and grinding. The phylogenetic trend in tooth reduction within the placodonts Paraplacodus, Placodus, especially in Cyamodus but also Placochelys, and Henodus within 11 My appears to have been a result of this plant-feeding adaptation and may even explain the origin or at least close relationship of the earliest Upper Triassic turtles as toothless algae and jellyfish feeders, in terms of the long-term convergent development with the sirens.

Evolution of white and megatooth sharks, and evidence for early predation on seals, sirenians, and whales

The early white shark Carcharodon Smith, 1838 with the fossil Carcharodon auriculatus (Blainville, 1818) and the extinct megatooth shark Otodus Agassiz, 1843 with species Otodus sokolovi (Jaeckel, 1895) were both present in the European proto North Sea Basin about 47.8 - 41.3 m.y. ago (Lutetian, early Middle Eocene), as well as in the Tethys realm around the Afican-Eurasian shallow marine habitats. Both top predators developed to be polyphyletic, with possible two different lamnid shark ancestors within the Early Paleocene to Early Eocene timespan with Carcharodon (white shark line-age) and Otodus (megatooth shark lineage). Their sawblade teeth developed during the early Paleogene as the result of adaptation to feeding on various marine new rising mammals, coinciding with three main waves of evolutionary emergence of seals, sirenians, and whales in parallel with the evolution of these large predatory sharks. Megatooth sharks specialized in hunting whales and sirenians only on the coastal shelves of warm oceans and disappeared globally in the Pleistocene due to climate change and ocean cooling. The cold-water adapted early white sharks have survived until the present day with body temperate change adaptation in warm to temperate oceans and are proposed to have specialized on coastal seal hunting already50 m.y. ago.

Palaeogeographic reconstruction of Minchin palaeolake system,South America: The influence of astronomical forcing

Current palaeoclimatic reconstructions for the R＆#237;o de la Plata region during the latest Pleistocene （30,000 e10,000 yr BP） propose dry conditions, with rainfall at the Last Glacial Maximum amounting to one-third of today＇s precipitation. Despite the consequential low primary productivity inferred, an impressive megafauna existed in the area at that time. Here we explore the influence of the flooding from a huge extinct system of water bodies in the Andean Altiplano as a likely source for wet regimes that might have increased the primary productivity and, hence, the vast number of megaherbivores. The system was reconstructed using specifically combined software resources, including Insola, Global Mapper v13, Surfer and Matlab. Changes in water volume and area covered were related to climatic change, assessed through a model of astronomical forcing that describes the changes in insolation at the top of the at-mosphere in the last 50,000 yr BP. The model was validated by comparing its results with several proxies （CH4, CO2, D, 18O） from dated cores taken from the ice covering Antarctic lakes Vostok and EPICA Dome C. It is concluded that the Altiplano Lake system drained towards the southeast in the rainy seasons and that it must have been a major source of water for the Paran＆#225;-Plata Basin, consequently enhancing primary productivity within it.

The Discovery of a Crinoid Community in the LateTriassic Zhuganpo Formation of Guizhou Provinceand Its Geological Significance

Recently a rich and well—preserved crinoid community including Traumatocrinus and Encrinus has been found in the Late Triassic Zhuganpo Formation in Guanling and Xingyi, Guizhou province, China. Among the fossils Traumatocrinus is the richest, and most of it occurs as clusters, with each cluster containing 3–42 crinoid branches. Study of the stem and calyx of Traumatocrinus shows that the number of stem-joints (columnals) is equal to the total stem length × K (5.85 per cm × stem—diameter). There are about 376 first- and second—order columnals on the whole stem. This number seems to coincide with the number of days in a year at that time. According to the present study of the palaeoecological environment of the crinoid community, it is considered that the reproduction and preservation of the crinoid community were controlled by the Late Triassic regression and the restricted bay of an interior sea behind the S—shaped shoal zone.

Early Cretaceous shifting of Zoophycos in the Ouarsenis Mountains(northwestern Algeria)

Early Cretaceous succession of the Oued Fodda Formation in the Ouarsenis Mountains(northwestern Algeria) is mainly composed of marl—limestone alternations, which are subdivided into four informal units(Units 1 to 4), based on distinct lithological, stratonomical, and ichnological features. The ichnological analysis reveals a low diversity of the trace-fossil assemblage, which is exclusively reported from Units 2 and 3.The ichnoassemblage contains six ichnotaxa(Chondrites intricatus, Ophiomorpha isp., Planolites isp., Thalassinoides isp., Zoophycos brianteus, and Zoophycos cauda-galli), among which Zoophycos and Chondrites are the most common elements of the assemblage and occur in distinct mud-rich substrates showing different bioturbation intensities. The development of Zoophycos in the middle part of Unit 2 shows a high degree of bioturbation(bioturbation index(BI) = 4). Zoophycos specimens are of large size, between 45 cm and 75 cm in width, which were interpreted to have formed in a lower offshore environment where the oxygenation amount was optimal, the sedimentation rate was low, and the benthic food was abundant on the seafloor. Toward the upper part of Unit 2, Zoophycos-bearing levels exhibit a less intense degree of bioturbation(BI between 1 and2) in contrast to Planolites-and Chondrites-bearing levels which have a bioturbation index(BI) between 3 and4. At these levels, Zoophycos displays relatively small, coiled to U-shaped spreiten, probably in response to stressful and dysoxic conditions prevailing in the water bottom. With improved oxygenation in a quiet lower offshore to shelf margin environment in Unit 3, the benthic organisms recovered, as represented by medium to large size Zoophycos in association with Ophiomorpha and scarce Chondrites burrows, even if the overall bioturbation intensity is very low. The combination of trace-fossil assemblage and lithofacies of the Oued Fodda Formation indicates relatively stable outer shelf environments below the storm wave base, which corresponds classically to the lower offshore to shelf edge environments, and the prevailing palaeoecological conditions are optimal and stressful for the benthic organisms.

Ecology of testate amoebae and their potential use as palaeohydrologic indicators from peatland in Sanjiang Plain, Northeast China

Testate amoebae are sensitive indicators of substrate moisture in peaflands. Over the last decades, they have been studied to reconstruct hydrological changes since the Holocene. However, these studies have been geographically restricted to North America and Europe. We conducted the first investigation of testate amoebae on the largest continental fresh water wetland in the Sanjiang Plain, China. The objectives of this study were to provide baseline data on the ecology of testate amoebae in the peatlands of Northeast China and to assess the potential of using them as environmental indicators in this ecosystem. We examined modem testate amoeba assemblages and species-environmental relationships at 46 microsites within 5 waterlogged depressions. The environmental parameters measured included： depth to water table, pH, and loss on ignition. The results showed that the dominant species were Trinema complanatum type, Euglypha rotunda type, Euglypha strigosa type, and Centropyxis cassis type. Redundancy analysis demonstrates that water table depth has the most important effect on testate amoeba assemblages, explaining 16.7% （p=0.002） of the total variance, pH was not a statistically significant factor for testate amoeba assemblages. Weighted averaging and weighted averaging partial least squares models were used to build transfer functions for depth to water table. The best performing transfer function was generated by the weighted averaging partial least squares model with an r^2LOSO of 0.62 and RMSEPLoso of 6.96 era. Results indicate that testate amoebae in waterlogged depression peatland have the potential to be used as indicators for hydrological changes and for palaeohydrologic reconstructions in the Sanjiang Plain.

The first occurrence of Phlebopteris dunkeri and P. woodwardii(Matoniaceae) from the middle Jurassic of Iran

The coal horizons of the Middle Jurassic Hojedk Formation of East-Central Iran are fossiliferous, bearing numerous well-preserved fossil plants, comparable to the Shemshak Group/Formation in the Alborz Mountains in Northern Iran. Here we present two recently discovered fossil taxa from the Middle Jurassic Hojedk Formation of the Tabas Block(Central Iran). Based on their distinct morphologies, impression/compression specimens can be assigned to Phlebopteris dunkeri(Schenk) Schenk(Palaeontographica 23: 157–163, 1875) and P. woodwardii Leckenby(Quarterly Journal of the Geological Society 20(1–2): 74–82, 1864), belonging to Matoniaceae. This is the first record of these two taxa in Iran. Taxa belonging to Equisetaceae, Marattiaceae, Dipteridaceae, Schizaeaceae, Dicksoniaceae,Caytoniales, Bennettitales, Cycadales and Podozamitaceae were observed as accompanying taxa in the studied section. Ecology comparison of the Hojedk Formation plant fossils with the extant relatives of the fossil plant taxa occurring in these deposits indicates accumulation of the host strata under a moist warm(tropical to subtropical)climate during the Middle Jurassic.

A latest Permian non-reef calcisponge fauna from Laibin,Guangxi,southern China and its significance

A calcisponge fauna occurs in uppermost Permian Conodont Clarkina meishanensis yini zone of the sequence exposed in the vicinity of Laibin, Guangxi Zhuang Autonomous Region, southern China. The fauna is dominated by one thalamid species, Arnblysiphonella vesiculosa de Koninck, 1863, and one new scterosponge genus and species, Radiofibrosclera laibinensis gen. et sp. nov. They are associated with a few other accessory species, including the thalamid sponges Amblysiphonella laibinensis Deng, 1981, Colospongia sp., Polvcystocoelia sp., and the inozoan sponge Acoelia discontinua sp. nov. Though the individuals are abundant, the species diversity is very low. Without common calcisponge components of Changhsingian reefal faunas, the assembtage is interpreted as not a reefal fauna. The water depth at which they dwelled was less than 105 m, and more probably tess than 40 m. Its occurrence indicates a significant sea-level drop at the end of Late Permian Changhsingian Age.

Function of Permian Special Gastropod Faunas in the Upper Yangzi Area to Determining Sedimentary Facies and Their Significance for Searching for Mineral Resources

The 'Upper Yangzi Area' includes a greater part of Guizhou Province and extensive regions of the eastern part of Sichuan Province and Yunnan Province. This area was a stable plateform with varied sedimentary environments during the Permian.A lot of carbonate strata, clastic strata, coal-bearing strata, siliceous strata, etc. deposited in this area during Permian. In this period, adapting themselves to varied environments,

Fruits of Scirpus(Cyperaceae) from the early Miocene of Weichang,Hebei Province,North China and their palaeoecological and palaeobiogeographical implications

This paper describes the fossil fruits of Scirpus weichangensis X.Q.Liang,sp.nov.from the early Miocene of Guangyongfa Village,Weichang County,Hebei Province,North China.The fossil fruits are obovate in shape and their lateral sections are plumply trigonous.The cell walls of the surface are straight.The persistent stout bristles have downward-directed barbellae in distal 1/2.The occurrence of the fossil Scirpus indicates that Guangfayong was a wetland in the early Miocene.Based on the fossil data,the genus likely originated in Western Siberia in the Oligocene,spread during the Miocene,and was finally distributed worldwide in the Holocene.