REVUE DE MICROPALEONTOLOGIE最新文献

The Class Ostracoda provides a well preserved and diverse microfossil succession throughout the Aptian Santana Group, Araripe Basin, Brazil. The Santana Group, consisting of the Barbalha, Crato, Ipubi and Romualdo formations, records the post-rift sequence (Alagoas local stage) of the Gondwana break-up. The Alagoas Stage is characterised by ostracods grouped as Cytheridea? spp. 201–218 of which several have been identified as belonging to Pattersoncypris Bate and Damonella Anderson. From 2 well cores and 10 outcrops of the Santana Group, 25 taxa were identified, 5 of which are here newly described. Throughout the Santana Group, Pattersoncypris micropapillosa Bate and Damonella grandiensis Tomé, Lima Filho and Neumann were recovered. Restricted to the Barbalha Formation, Candonopsis? alagoensis Tomé, Lima Filho and Neumann and Pattersoncypris cucurves nov. sp are abundant. The Crato Formation shows higher ostracod diversity with Damonella grandiensis being the most abundant and associated with Cypridea araripensis Silva, Brasacypris subovatum Do Carmo, Coimbra, Whatley, Antonietto and Citon, Damonella pumila nov. sp., Pattersoncypris alta (Antonietto, Gobbo, Do Carmo, Assine, Fernandes and Silva), Zonocypris berthoui Piovesan, Melo, Cabral and Guzmán, Zonocypris dorsoconvexa Piovesan, Melo, Cabral and Guzmán, Ilyocypris coimbrai nov. sp., Neuquenocypris berthoui Colin and Dépêche, Neuquenocypris sp., Rhinocypris spinata nov. sp., Theriosynoecum silvai (Silva), Theriosynoecum sp., Timiriasevia? sp. and Alicenula martinsi (Silva). The Ipubi and Romualdo formations record abundant Pattersoncypris crepata (Do Carmo, Coimbra, Whatley, Antonietto and Citon) in association with P. alta, Pattersoncypris kroemmelbeini nov. sp., P. symmetrica (Krömmelbein and Weber) and Alicenula martinsi (Silva). Theriosynoecum colini Do Carmo, Coimbra, Whatley, Antonietto and Citon, Ilyocypris coimbrai nov. sp. and Rhinocypris spinata nov. sp. also occur in the Ipubi Formation.

The Ladinian stage in the Middle Triassic is poorly documented in terms of marine ostracods diversity. Silicified ostracods have been retrieved from three sections of Middle Triassic age in Slovenia (Rob, Kamna Gorica, Vintarjevec), providing new insights into the taxonomic structure and distribution. Sixty-four species belonging to 33 genera and 13 families are here reported, including two newly described species: Mirabairdia slovenica sp. nov. and Leviella alexi sp. nov. Not considering assemblages that are significantly incomplete, the assemblages point to stable subtidal conditions. The occurrence of several species shows the existence of migration routes between the Germanic Basin and the Slovenian Basin in the Ladinian.

Anatoliella Sirel (type species A. ozalpiensis) was described from the Paleocene of Turkey as an agglutinated conical-trochospiral larger benthic foraminifera displaying a complex exoskeleton (reticulate network) and endoskeletal pillars, originally ascribed to the Ataxophragmiidae. Later, Anatoliella has been included in the eponymous family Anatoliellidae Sirel characterized, alongside other features, by a complex exoskeleton (beams and rafters) and an endoskeleton consisting of thick pillars. A reinvestigation of Anatoliella, based on the original illustrations and specimens from the Paleocene of Iran, reveals a different test structure. We conclude that the pillars recognized by Sirel in longitudinal sections must instead be referred either to first order vertical partitions (beams) in shallow tangential sections, or to a central helicospiral columella in axial sections, leading to an emendation of the diagnosis of the genus. Consequently, the diagnosis of the family Anatoliellidae is also emended because of these new structural observations. A new suprageneric classification for Anatoliella and the allied genus Gyroconulina Schroeder & Darmoian is put for discussion.

Mixed siliciclastic-carbonate deposits accumulated in several satellite sub-basins at the southern margin of the Guadalquivir Basin, the foreland basin of the Betic Cordillera (S. Spain). The prevailing coarse-grained sediments and deposition in shallow-water settings make it difficult to establish the precise age of the complete successions. For this reason, in previous studies, these deposits were attributed to the late Tortonian, although a Messinian age was not totally ruled out. The age of the upper Miocene deposits in the central part of the Guadalquivir Basin is here re-evaluated based on the analysis of several sections distributed in different areas: Antequera, Iznájar-Cuevas de San Marcos, Teba, and Bobadilla Estación. According to planktonic foraminifer and nannoplankton assemblages, the marine sedimentary infill of this sector of the southern margin of the Guadalquivir Basin is late Tortonian-early Messinian (late Miocene) in age. The occurrence of marine deposits characterized by the dominance of Globorotalia miotumida group, dextrally-coiled G. scitula, and the presence of G. margaritae, Globigerina multiloba, Discoaster quinqueramus, Amaurolithus primus, A. amplificus, and Reticulofenestra rotaria at the northern end of the Guadalhorce Corridor, the last active gateway in the Betic Cordillera connecting the Atlantic and the Mediterranean, indicates that it remained open until the early Messinian.

This paper describes a new deep-sea foraminifer which has possibly evolved a way to use sediment particles from its surroundings to increase its density. The benthic foraminifer recovered from Red Sea planktonic ooze shares some similarities with two well-established Uvigerina species Uvigerina auberiana d'Orbigny, 1826 and the extinct Uvigerina auberiana var. attenuata Cushman & Renz, 1941. However, it differs from the two species mainly by the incorporation of sediment grains into its external wall. Uvigerina agglutinata n.sp. is characterized by its initially triserial coiling, which changes to biserial in the middle part and eventually becomes uniserial in final whorl. The most diagnostic feature of this species is the incorporation of different shapes and sizes of detrital calcium carbonate grains into its outer wall.

New biostratigraphic data about the Lower Cretaceous “Orbitolina limestone” (Shah Kuh Formation) that transgressively overlies the Anarak Metamorphic Complex in Central Iran is provided from a section near Anarak. The presence of the Praeorbitolina biozone at the base documents an early Aptian age. In the late Aptian, the “Orbitolina limestone” is topped by an emersion surface. This level/event might correspond to the beginning of the supra-regional late Aptian sea-level lowstand. It is followed by carbonates ascribed to the Albian Bazyab Formation, although no precise age indicator has been observed. From the Shah Kuh Formation, the previously unrecorded species Paleodictyoconus conica (rect. conicus) Matsumaru in Matsumaru and Furusawa, 2007 (early-late Aptian of Japan) is described and taxonomically revised as Neorbitolinopsis conica (Matsumaru) comb. nov. A literature review (including other records from Iran under different names or in open nomenclature) leads to the conclusion that Neorbitolinopsis conica represents a marker for the upper Bedoulian to Gargasian stratigraphic interval in this area. The studied section also provides the first record of Palorbitolinoides Cherchi & Schroeder from the early Aptian of Central Iran.

Freshwater ostracods were recovered from limestone strata belonging to the Nam Phong Formation exposed at Ban Non Tum section in Chaiyaphum Province, northeastern Thailand. The examined rocks were collected above the oldest known dinosaur footprints site in Thailand. All recovered ostracods belong to the Superfamily Darwinuloidea and were attributed to three species: Suchonellina sarytirmensis (Sharapova) in Mandelstam, 1947, Suchonellina. sp. A and Suchonellina sp. B. The ostracods represent the first known record of Jurassic darwinuloideans in Southeast Asia. The ostracod assemblage and microfacies are indicative of deposition in a shallow and low energy fluvio-lacustrine regime.

Well-preserved Early Triassic radiolarians were recovered from lower Smithian (lower Olenekian) beds in NE Vietnam. The radiolarian assemblage consists only of Paleozoic relict species of Latentifistularia and some entactinarians. Three latentifistularian species, Ruzhencevispongus vietnamensis nov. sp., Tetragregnon chilangensis nov. sp., and Tetragregnon langsonensis nov. sp., belonging to the families Ruzhencevispongidae Kozur and Tetratormentidae Nestell and Nestell are erected herein. The entactinarian family Triassothamnidae nov. fam. and one new genus and two new species of Langsonsphaera pseudocubica nov. gen. nov. sp. and Stigmosphaerostylus amabilis nov. sp. are also described. In this region, the Paleozoic-type radiolarian groups Latentifistularia and Entactinaria survived across the Permian–Triassic boundary and were present during the Induan–early Olenekian interval. Thus, in the eastern Tethyan seaway near the equator, the true extinction of some Paleozoic radiolarian groups took place at the middle of the Early Triassic, immediately after the Smithian, rather than during the Permian–Triassic crisis.

Peneroplis turonicus Said and Kenawy is a poorly known benthic foraminifer that was originally described based on isolated specimens from the Upper Cretaceous of Egypt. Specimens from the Cenomanian Sarvak Formation of Iran indicate the presence of a finely agglutinated test wall displaying a pseudo-keriothecal texture, therefore, excluding this taxon from the porcelaneous Miliolida, namely family Peneroplidae. Based on the test morphology, wall structure and foraminal features, the species is herein tentatively assigned to Neodubrovnikella Schlagintweit and Rashidi (order Loftusiida), with the new combination Neodubrovnikella turonica (Said and Kenawy). A critical literature review leads to the conclusion that N. turonica represents a southern Neotethys Cenomanian marker taxon reported so far from Italy, Slovenia, Croatia, Kosovo, Greece, Lebanon, Syria, Morocco, Egypt, Turkey, Iraq, and Iran. Therefore, Neodubrovnikella does not represent a Maastrichtian genus as previously assumed but is as old as Cenomanian, disappeared from the fossil record in the proximity of the Cenomanian-Turonian boundary and reappeared after a considerable gap and ghost range.

The presence and diversity of polycystine radiolarians in the North-Eastern Mediterranean Sea is explored for the first time through the analysis of sinking particles obtained from sediment traps moored in three open marine sites. In total, thirty species are identified for which we provide appropriate references and illustrations to clarify the species concept followed in this study; 13 of the identified species are Spumellarians, 16 are Nassellarians and one is an Entactinarian. The highest diversity is recorded in the Ionian site, in which 23 species were observed during November 2014, with approximately as many Nassellarian species as Spumellarians; a large number of species are in common with the fauna reported from the Adriatic Sea, off Dubrovnik, but interestingly, 16 others are not. The lowest levels of radiolarian diversity, with 3 to 4 species at best, were observed in the north Aegean and Cretan Sea sites. Our observations improve also the paleobiogeographic knowledge of two polycystine species, one of which (Gonosphaera primordialis Jørgensen) was known previously from the high latitudes of both the northern and southern hemisphere and the other (Qiuripylolena chikuchik Zhang and Suzuki) from the Pacific ocean.