Annales de Paleontologie最新文献

The lake of Tunis, located in northern Tunisia, is part of the coastal wetlands sensitive to climatic and anthropic variations. This fragile ecosystem was an open bay 190 ka BP ago. Today, it is separated from the Mediterranean by a sandy barrier fed mainly by the Madjerda wadi. This study, based on a multidisciplinary geological approach, examines the evolution of the dynamics of the Tunis Lake, as well as the recent environmental changes that control the sedimentation. Two cores LN1 (55 m) and LS1 (40 m) were collected in the alluvial deposits, respectively in the North-East and South-East of the Lake. These cores have been studied in detail to determine the spatio-temporal distribution of the sedimentary stock. The data from this study complemented by those from previous work allowed us to refine and establish spatio-temporal correlation scenarios of the sediments filling the Tunis lagoon. These correlations are established between the LN1 core and the core taken at the SE (LS1). Spatial and temporal monitoring of sediment deposition in these cores has revealed a general regressive evolutionary trend, from a frankly marine environment to a lagoon environment more or less communicating with the sea, from the Middle Pleistocene (an age between 159 and 205 ka) to the present Holocene. The identification of ostracod associations typical of open marine or lagoon environments and of benthic foraminifera associations of lagoon environments has allowed us to trace the history of the Tunis Lake over the last two millennia. It begins with an open marine environment (around 2030 years BP) followed by an open lagoon environment around 1700 years BP.

Late Cretaceous Torreites milovanovici, pertaining to Hippuritids (rudists) as marine heterodont bivalves, from SW Iran (northern Shiraz), is the centerpiece of this study. It is the first specimen of the Torreites genus recorded in Iran. More than 25 Torreites specimens were collected from the medium-bedded carbonate layer of the Upper Cretaceous succession of the study area. As well as in Iran, T. milovanovici specimens are recorded from Oman, and United Arab Emirates (UAE), although other species are found in Cuba, Jamaica, and Mexico. The Torreites-bearing bed is attributed to the clastic lower unit of the Tarbur Formation in Zagros Basin which is overlain by the carbonate upper unit of this Formation. Referring to field and laboratory observations as well as different previous references the Torreites-bearing carbonate layer in the study section can be ascribed to the Campanian. T. milovanovici specimens in Iran are compared with those recorded in Oman and UAE, using some determinative parameters. They show similarities in angles and size. Finding the species in a new area can be inspiring for future studies. It enhances the paleobiogeographical distribution of Family Torreitidae in the world and matching them chronologically can reveal some new evolutionary trends.

The present work is focused on the hipparionine remains from the late Miocene to early Pliocene deposits of the Haritalyangar areas, Himachal Pardesh, India. These remains are taxonomically ranked to five genera (Plesiohipparion, Proboscidipparion, Cormohipparion, Sivalhippus, and Eurygnathohippus) and seven species. The described taxa are predominantly known from China, Africa and the Indian subcontinent. Among these, Proboscidipparion is reported for the first time from the Siwaliks; the material assigned to Plesiohipparion sp. is a potential candidate for a new species. Hipparionines from this area have long been poorly known and are helpful to understand the palaeontological context of the Indian Siwalik mammalian fauna. The hipparionines suggest a wide variety of environmental conditions ranging from grasslands to forests.

The Pliensbachian succession of the Central Unit of the South Riffian Ridges domain consists of four formations. The second one, the Jebela Formation, is rich in brachiopods especially at Jbel Dhar N'Sour Anticline. Twenty-three species belonging to three orders (Spiriferida, Rhynchonellida and Terebratulida), and eight genera have been identified in addition of seven species of bivalves. Most of the studied brachiopod taxa are described and illustrated for the first time from the Pliensbachian succession of the South Riffian Ridges domain and Morocco in general. Several of these taxa have wide geographic distributions in the Peritethyan basins of the northern and the southern margins of the western Tethys and the Subboreal Domain of NW Europe.

In the present paper, we describe and figure some rare lower Aptian (Lower Cretaceous) helical ammonoids from the Deshayesites deshayesi Zone of the Argiles à Plicatules Formation (Paris Basin, NE France). Those are the only helical ammonoids known in this zone so far. They were only occasionally evoked in literature and this is probably on the basis of the specimens here described that, according to us, the genus Toxoceratoides (Helicancylidae) was wrongly regarded as possessing an early helical spiral part. We demonstrate here that these specimens are not belonging to Toxoceratoides nor Helicancylidae: they are interpreted as ‘abnormally’ helical representatives of the genus Ancyloceras (Ancyloceratidae) or a new taxon of Ancyloceratidae.

An old find of a graptolite from the Eifelian Jemelle Formation, combined with the recent discovery of an exceptionally well-preserved specimen from the Upper Frasnian (Matagne Formation), allow documentation of the geologically oldest and youngest dendroid fossils from the Devonian of Belgium. Both are ascribed to the long-ranging genus Callograptus (Acanthograptidae). These records enlarge the sparse knowledge of graptolite diversity and occurrences along the southern margin of Laurussia during the mid-Paleozoic. In Belgium, Devonian dendroids are exclusively known from the Dinant Synclinorium. The Devonian dendroid faunas previously reported from the Eifelian, Givetian and Frasnian of the Ardenne–Rhenish massifs (Belgium and Germany) are of low diversity (one to five species per locality). The specimens, generally inedaquatelly preserved, were ascribed to the genera Callograptus, Dictyonema, Palaeodictyota?, and Ruedemannograptus? In these massifs, Carboniferous dendroids are only known from the Viséan (Moliniacian) Denée Konservat-Lagerstätte. Other but undocumented reports of dendroids (and rhabdopleurids) are from the historical type area of the Tournaisian Stage (Tournai area, Brabant Parautochthon). Rhabdopleuridae from the Viséan–Serpukhovian of the Campine Basin (Turnhout borehole) remain incompletely known in the absence of the previously described material.

Miocene scleractinian corals were documented for the first time in the Fırat Formation of Sarıca village, Eğil district of Diyarbakır, SE Turkey. The fauna consists of four hermatypic species belonging to three families: Diploastrea taurinensis (d’Achiardi, 1868), Tarbellastraea reussiana (Milne-Edwards and Haime, 1850), Echinopora gemmacea (Lamarck, 1816) and Montastraea pelouaensis (Chevalier, 1954). The morphospecies described here are typical of the early Miocene (Aquitanian-Burdigalian) and show that the Fırat Formation coral community was composed of shallow and subtropical reefs of Mediterranean Tethys palaeobiogeographical affinity. The examined species are reef components found in tropical and subtropical oceans, as are the majority of zooxanthellae. The species were upper photic zone related, had massive colonial growth morphology, and lived in a shallow tropical-subtropical marine palaeoenvironment at a depth of up to 50 m. They grew on hard ground, clean water, and normal salinity and required a minimum seawater temperature of 18 ̊C; however, they were most abundant at water temperatures ranging from 22 to 26 ̊C in high-moderate water energy. Consequently, this fossil assemblage will not only improve our knowledge of scleractinian coral diversity and morphological variation in SE Turkey but will also provide an important background for future studies of coral taxonomy, diversity and biogeography of the region.