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Core-samples from wells and an outcrop located on the Voronesh Anticline in the southeastern part of the Russian Platform contain Late Cretaceous radiolaria. 83 species are described and illustrated (SEM and transmitted light images) from Santonian-early Campanian deposits, and two assemblages are distinguished. The older assemblage with Alievium gallowayi, Archaeospongoprunum bipartitum, Archaeospongoprunum. cf. A. salumi as well as other less age-diagnostic taxa, is interpreted as Santonian correlative with the Euchitonia santonica-Alievium gallowayi Assemblage Zone of the Moscow Basin (Vishnevskaya 1993). The younger assemblage, of Santonian – early Campanian age, contains Patulibracchium cf. P. davisi, Crucella irwini, Cryptamphorella sphaerica, Praeconocaryomma californiensis, Dictyomitra lamellicostata among other species and is correlative with the Orbiculiforma quadrata-Lithostrobus rostovtsevi Assemblage Zone of the Moscow Basin. In terms of inter-regional faunal comparisons, both of the Voronesh Anticline radiolarian assemblages demonstrate relatively close affinities to coeval rocks from the Volga River region, but less similarity to the assemblages from the Moscow Basin. Only a few of the common endemic species of Siberian assemblages occur in our samples. On an inter-regional level, the radiolarian assemblages described herein have similarities with assemblages reported from Japan and California. Index-species characteristic for the Santonian-Campanian radiolarian biozonations of the Atlantic and Pacific Oceans are not found in our collection. However, the presence of many cosmopolitan species known from the European Platform, Japan and California suggests a marine connection between the Voronesh Anticline region, the western Atlantic and eastern Tethys during Santonian-Early Campanian time.
Diverse and significant well-preserved radiolarians were obtained from ribbon-bedded chert in an area to the north of Chiang Dao city, Chiang Mai, northern Thailand. The area is mainly composed of an accretionary complex, which is recently considered as a key part of a newly described suture zone in the Southeast Asian region. Devonian radiolarian-bearing cherts are exposed within this area. These cherts contain identical radiolarian faunas, which include nine families and forty-three species belonging to thirteen genera. Among these faunas, Entactinaria are dominant. Three new species, Trilonche chiangdaoensis, Trilonche dihelicis and Trilonche vachardi, are erected and about thirty species, which have never been reported from Thailand, are also present. The Trilonche minax (lower Frasnian) radiolarian assemblage from Australia is recognized in the area. The radiolarian faunas are systematically described and relationships between them and fauna from adjacent radiolarian provinces are discussed. These cherts with their radiolarian faunas are evidence for the presence of a wide paleo-ocean once existed between Shan-Thai and Indochina continental terranes.
The present study was designed to gain insight into the protists and fungi that made up the microbiota in the past, fossilized in two different substrates: amber and sandstone. The amber, dated as Lower Cretaceous, was from Álava in northern Spain, while fossil-bearing sandstone rocks were collected from the Linnaeus terrace and Mount Fleming regions of Antarctica. When examining this type of inclusion in hard substrates, it first has to be established whether the microorganism is mummified or only partially mineralized. In the latter case, some of the organism's autofluorescence may be preserved. In our amber samples, light microscopy revealed a very well preserved microcenosis in what must have been a semiaquatic habitat comprised of several types of protozoa including Amoeba, Paramecium and Astasia (Euglena), Amebas limax and the colpodid ciliate Pseudoplatyophrya nana, as well as an abundant fossilized mycelium. The SEM-BSE procedure provided us with ultrastructural details of the fungi and protozoa, especially amoebae and flagellates. In the sandstone samples from Linnaeus terrace, it was possible to identify presumptive diatoms. Ultrastructural details were well-preserved in a fossil Trebouxia-type microalga from Mount Flemming, including the inner chloroplast area normally occupied by the pyrenoid. This fossilized microalga was shown by energy dispersive spectroscopy (EDS) to contain high Si levels in the pyrenoid zone, and high Fe levels in the area corresponding to the chloroplast periphery, peripheric cytoplasm and cell wall. In sandstone from Linnaeus Terrace, fossilized algae showed no central core containing Si, and the entire cell appeared to be completely filled with Al, K and Fe, with Fe most intensely observed within the algal wall. The present observations suggest that a well-preserved cell ultrastructure is the best criterion of biogenicity.
Plant pathogens Colletotrichum causing leaf spot and red rot disease, Erysiphe and Uncinula responsible for producing powdery mildews and microthyriaceous ascostromata making black spot on leaves were recovered from the Group A type of coprolite of Matley from the Lameta Formation. This was supposed to be voided by Isisaurus (Titanosaurus) belonging to sauropods. The presence of these fungi in the coprolites indicates that the said dinosaur ate the leaves. As these pathogens occur in all types of plants it is postulated that the Isisaurus used its long, slender neck to browse the trees like modern camels and giraffes. The coprolites also yielded Glomus – a mycorrhizal fungus which probably penetrated into it after it was voided on the surface. On the basis of epiphyllous fungi it is postulated that the dinosaurs lived in a tropical-subtropical climate.
Early Aeronian (middle Llandovery, Early Silurian) radiolarians collected from calcareous nodules of the Kallholn Formation in the Siljan district, Sweden, are described. Seven genera and 11 species, including one new family Gyrosphaeridae and two new species, Palaeoscenidium kuriharai and Gyrosphaera primigena, are described. This fauna is characterized by the dominance of large spherical radiolarians, which constitute 54% of the total number of specimens per nodule. The fauna is similar to the middle Telychian fauna insofar as it is dominated by Haplotaeniatum cathenatum. However, it can be distinguished from the late Rhuddanian fauna by the sparse occurrence of H. aperturatum. These data suggest that the period from the Aeronian to the middle Telychian was marked by the dominance of H. cathenatum.
Radiolarian spines, a morphological innovation, are believed to have evolved in the Aeronian. The time of radiolarian diversification corresponds to that of other planktonic/nektonic faunas including graptolites, chitinozoans, and fish, which suggests that marine macroplanktonic/nektonic faunas and microplankton diversified simultaneously in the Aeronian.
A new Orbitolinid foraminiferal genus Praeorbitolinoides (type species Praeorbitolinoides japonica, n. gen., n. sp.) is described from the Lower Aptian Orbitolina-bearing limestone, Shimanoshita Mudstone, Lower Yezo Group, Hokkaido, Japan. Praeorbitolinoides, gen. nov. is characterized by the presence of early postembryonic chambers, covering on the embryonic and periembryonic chambers, eccentric in position. Praeorbitolinoides japonica, n. gen., n. sp. is associated with Paleorbitolina lenticularis (Blumenbach) and Mesorbitolina parva (Douglass).