Ostracodes et incursions marines dans l’Holocène terminal du lac Retba (Cap Vert, Sénégal)

The study of marine incursions based on ostracods is carried out for the first time in the late Holocene, with core sediments of the Lac Retba edge. Twenty-four species are identified along the core; most of them are encountered in the Gulf of Guinea shelf and its adjacent lagoons. For the first time Buntonia olokundudui Reyment and Van Valen, Hermanites foveolata Omatsola and Soudanella africana Omatsola are recorded in Senegal. Four ostracods assemblages are evidenced along the core, corresponding to different stages of the lake evolution. Cyprideis nigeriensis Omatsola, Neomonoceratina iddoensis Omatsola and Aglaiocypris gambiensis Witte dominate the first assemblage; they indicate a lagoon slightly open to the sea and bordered with mangrove swamps under relatively humid climate conditions. The second association yields the most diversified ostracod fauna with C. nigeriensis, N. iddoensis and high proportion of reworked “marine species” which evidence a marine little gulf bordered by mangrove under a humid climate. The third, monospecific association (C. nigeriensis) is typical of a closed and hypersaline lagoon under dry climate conditions. An oligospecific association with C. nigeriensis, Pseudoconcha omatsolai Witte and very scarce reworked “marine species” occurs at the top of the core and characterises an open and hypersaline lagoon under arid climate conditions. Ostracods evidence two marine incursions. The first and the stronger one is dated here for the first time between 1420 and 1250 years B.P. The more recent is the weaker and is not yet dated. Evidence of the beginning of the Retba Lake closure towards 680 years B.P. appears at the top of the core, as indicated by high reduction of ostracods abundance, predominance of reticulate Cyprideis and disappearance of the “marine species”, while salts precipitated at the bottom of the lake.     

Les ostracodes plio-pléistocènes de la côte orientale de la Péninsule du Cap Bon (Tunisie)

This article concerns the study of the ostracods of the Upper Pliocene-Lower Pleistocene sedimentary deposits cropping out along the south-eastern coast of the Cape Bon Peninsula (Tunisia, Hammamet region, Sidi Khelas section). Fourteen samples were taken along a thirty-two-meters thick sedimentary silico-clastic series. Seventy species of ostracods belonging to twenty-four genera were found. The autochthonous association, which originally lived in an environment located in the infralittoral and upper circalittoral stages of the benthic marine domain, is cyclically affected by inputs from the more superficial environments due to the presence of relatively well-developed lagoon and/or estuary environments in the surrounding coastal areas. Within the ostracod association, the presence of Bythocythere turgida – a true “northern guest” – is particularly significant. This species indicates that these sediments were deposited during the cold phases of the Early Pleistocene. Among the ostracods found, those belonging to the families Trachyleberididae, Hemicytheridae and Bythocytheridae, which are dominant and include particularly significant species from the environmental and paleoclimatic point of view, are systematically recorded and commented on. Some species that are probably new have been described and photographed, but are currently left in open nomenclature because of how few specimens have been found.     

Pleistocene Calabrian and Sicilian bioprovinces

During the Pleistocene, southern Calabria was the area through which several mammalian taxa dispersed into the Sicilian island via the Straits of Messina. The rich fossil record of Sicily allowed for the construction of a fairly detailed bio-chronological frame that is dated by correlation of vertebrate bearing deposits with marine deposits. At present five Faunal Complexes (F.C.), characterised by the occurrence of different taxa, have been recognised. The two older Faunal Complexes (Monte Pellegrino F.C.'xes Elephas falconeri F.C.) include taxa with differently marked endemic features denoting the occurrence of an insular system made up of geographically isolated small islands, with very difficult and sporadic connections with the mainland. The Lower Pleistocene physiographic evidence fits closely with data coming from palaeontologic evidence. In the younger F.C.'xes (E. mnaidriensis F.C., Pianetti S. Teodoro F.C. and Castello F.C.), faunal composition is becoming more similar to that of the southern Italian peninsula, endemisation is more moderate becoming absent in the youngest assemblages. This behaviour denotes that temporary connections with southern Italy occurred more frequently and extensively during Late Middle Pleistocene and Late Pleistocene. Possibly a sort of filtering barrier affected the dispersals that gave rise to the former phase of population of the E. mnaidriensis F.C. preventing small mammals from the mainland from entering the island. The vertebrate fossil record of southern Calabria is rather poor and no mammal deposit is apparently older than the Late Middle Pleistocene. The occurrence at Bovetto of a continental fallow deer (Dama dama cf. tiberina), closely related to the endemic Sicilian species D. carburangelensis of the E. mnaidriensis F.C., may document the first Pleistocene connection of southern Calabria to the Italian peninsula and the dispersal of the forerunners of mammals of the E. mnaidriensis F.C. in Sicily. The well-diversified continental faunas coming from Archi and from Iannì di S. Calogero, both containing remains of Homo sapiens neanderthalensis, may document a post-Tyrrhenian dispersal event through the Catanzaro isthmus. Data are still lacking for the correlation of these faunal assemblages with the scarcely endemic faunas of the Late Pleistocene Contrada Pianetti–San Teodoro F.C. of Sicily. No record of the mammal assemblages that gave origin to the fauna of the Castello F.C. has been recovered so far in southern Calabria.     

Late Pleistocene and Holocene chitons (Mollusca, Polyplacophora) from Uruguay: Palaeobiogeography and palaeoenvironmental reconstruction in mid latitudes of the southwestern Atlantic

Here we present a revision of the fossil record of chitons (Mollusca, Polyplacophora) of Late Pleistocene and Holocene marine deposits of Uruguay and discuss their potential for palaeoenvironmental reconstruction. Chitons were recorded as isolated valves in bivalve- and gastropod-rich assemblages. They are represented by the species Chaetopleura angulata (Spengler), C. isabellei (d’Orbigny), C. asperrima (Gould) and Ischnochiton striolatus (Gray). The last two species are recorded for the first time as fossils not only in Uruguay but also in South America. Exclusively recorded for the Late Pleistocene is the warm water species I. striolatus, whose current southern range limit is located in Santa Catarina, Brazil. Higher temperatures than at present are inferred for the Uruguayan coast during the Late Pleistocene, probably driven by the southward influence of the warm Brazilian Current along the eastern margin of South America. Chitons from Holocene deposits show a wider geographic distribution along the Uruguayan coast in comparison to current distributions. They are recorded where an estuarine and eurihaline fauna lives today, which suggests the former existence of marine conditions. This is explained by the westward displacement of the marine front in the Uruguayan coast during the Holocene transgressive events. Chitons have proven to be useful palaeoenvironmental proxies for the reconstruction of salinity and temperature trends in the Uruguayan coast during the climatic oscillations of the Late Pleistocene and Holocene epochs. As such, their patterns of distribution are related to the recent physical evolution of the Southwestern Atlantic Ocean.     

A new large barn owl (Aves, Strigiformes, Tytonidae) from the Middle Pleistocene of Sicily, Italy, and its taphonomical significance

A new species of Tytonidae, Tyto mourerchauvireae, is described from the Sicilian cave deposits of Spinagallo, Luparello and Marasà, which have yielded a common vertebrate fossil assemblages referred to the early Middle Pleistocene. T. mourerchauvireae nov. sp. shows a pronounced increase in body size compared to other congeneric taxa. It is larger than the extant Tyto alba and the extinct Tyto balearica and Tyto sanctialbani and comparable in size among the Mediterranean taxa only with the extinct Tyto robusta, which differs in some morphological characteristics of the long bones. The insular adaptations of T. mourerchauvireae nov. sp. and the differences from the other forms of the genus Tyto which spread through the Mediterranean area during Neogene and Pleistocene are discussed. The fossil assemblages of the early Middle Pleistocene of Sicily are dominated by extinct giant Gliridae of the genus Leithia and Maltamys; these taxa are regarded as the primary prey items of T. mourerchauvireae nov. sp. The Gliridae remains were analysed microscopically to detect possible modifications of bones and teeth caused by ingestion and digestion processes. This type of analysis, together with the qualitative study of the fossil assemblages, allows to show the taphonomical importance of T. mourerchauvireae nov. sp. as agent of accumulation in such Sicilian fossil assemblages. Incidentally the taxonomic validity of T. robusta is discussed and confirmed.     

Ostracoda and Mollusca biodiversity and hydrochemical features in Late Miocene brackish basins of Italy

Late Miocene brackish ostracods and molluscs collected in three Italian basins show noticeable differences in their taxonomic composition, despite their capability of dispersing across wide geographic areas. In the Venetian-Friulian Basin (northern Italy), the upper Tortonian sediments contain oligotypic ostracod assemblages including Hemicyprideis dacica dacica, Hemicytheria pejinovicensis, and Loxoconcha cf. L. josephi and few gastropods referable to Planorbidae and Stenothyroides, which are typical of the central Paratethys. In central Italy, the brackish ostracods and molluscs recovered from upper Tortonian-lower Messinian deposits from four Tuscan basins (Volterra-Radicondoli, Velona, Baccinello-Cinigiano, and Valdelsa) display high affinity at a generic level but strong endemicity at a specific level. At Cessaniti (southern Italy), the upper Tortonian unit contains oligotypic brackish ostracods and molluscs: Mediocytherideis (Sylvestra) posterobursa, Cyprideis ruggierii, Loxoconcha cf. L. biformata, and Zonocypris membranae quadricella characterise the ostracod fauna, while Granulolabium bicinctum and Hydrobia frauenfeldi are the dominant molluscs. The recovered ostracods have a strong affinity with brackish species from central and eastern Palaeo-Mediterranean areas, whereas the molluscs present a Paratethyan origin. Despite the fact that the basins are all brackish and partly coeval, the systematics of these assemblages highlights the absence of common species among the three studied areas. Geochemical analyses (stable isotopes and trace elements) are performed on ostracods, and ⁸⁷Sr/⁸⁶Sr ratios are established in molluscs and echinoids. The results suggest brackish environments with different compositions and origins of solutes in the three different areas. The Tuscan basins are characterised by brackish waters, with NaCl-enriched waters coming from aquifers of Triassic evaporite bedrock. The brackish deposits of the Venetian-Friulian Basin and Cessaniti are true marginal marine environments, although the northern basin may have been influenced by both the Paratethyan Sava Basin and the northern portion of the Palaeo-Mediterranean water bodies.     

Pliocene coastal palaeomorphology and ostracod faunas of the Bass Strait hinterland,southeast Australia

Early to late Pliocene sedimentary strata present across the northern Bass Strait hinterland, southeastern Australia yield extensive fossil proxy data relevant to the interpretation of high sea level coastal palaeomorphology. Within the Pliocene Whalers Bluff Formation exposed in coastal cliffs near the township of Portland, Victoria, marine microfossil faunas delineate two broad cycles of deposition. Both these sedimentary cycles are bound below by unconformity surfaces. Within the lower sedimentary cycle, a basal stress-tolerant (low diversity) marginal marine microfossil fauna devoid of ostracods and suggestive of bottom-water hypoxia, is succeeded by a diverse shallow marine ostracod fauna dominated by stenohaline species indicative of a sheltered (but open) oceanic embayment. This lower sedimentary cycle has an early Pliocene (Zanclean) age. Equivalent shallow marine (e.g. coastal embayment) deposits occur broadly across the coastal hinterland of southeastern Australia—reflecting the generally higher global sea levels of this time. The upper cycle in the cliff exposures at Portland is late Pliocene (Piacenzian) in age. Equivalent deposits across the Bass Strait hinterland are restricted to former incised river valley settings. Euryhaline estuarine/coastal lagoon Ostracoda are present throughout the upper cycle in the Portland cliffs. These are associated with a low diversity microfauna at the base of the upper cycle and a high diversity microfauna towards the top of the cycle. Early Pliocene coastal marine deposits can be distinguished from late Pliocene coastal marine deposits across the northern Bass Strait hinterland on the basis of the presence or absence of certain open marine (‘stenohaline’) ostracod species.     

The Pleistocene lake deposits of the NE Baza Basin (Spain): salinity variations and ostracod succession

The Guadix-Baza Basin in Spain covers an area of approximately 3000 km² and yields a sedimentary sequence ranging from Lower Miocene to Pleistocene. Twenty five meters of Lower Pleistocene lacustrine sediments have been located in the NE part of the Basin at about 1000 meters in altitude. This sequence which overlies dolomitic mud flat deposits consists of limestones, calcareous and dolomitic mudstones, dolostones, silty clays, sands and gravels. Salinity fluctuations and short dry episodes, related to lake level oscillations, have been recorded by textural, mineralogical and faunal changes throughout the sequence. Ostracods, which are the most commonly encountered fossils, permit to detect recurrent changes in water salinity and regime, and solute composition. The faunal changes indicate an alternation of slightly saline and bicarbonate-rich water (when ostracods and gastropods occur) with a saline NaCl-dominant water (in which ostracods, Cerastoderma bivalves and non-marine foraminifers are found).The frequent and recurrent hydrochemical changes in the Baza Basin in the Early Pleistocene point to a climate of high contrast like in the Mediterranean region today but with a greater availability of water within the system compared to the present situation in the area.     

Changes in calcareous nannofossil assemblages during the Mid-Pleistocene Revolution

The distribution of calcareous nannofossils are quantitatively analysed in high-resolution deep-sea core samples from North Atlantic DSDP Site 607 and Eastern Mediterranean ODP Site 967, between marine oxygen isotope stage (MIS) 35 and 15, in order to observe the response of calcareous nannofossils to the Mid-Pleistocene Revolution (MPR). Nannofossil abundance patterns show major variations through MIS 25–22 and distinct higher amplitude changes from MIS 21 upward, sometime clearly correlatable to glacial–interglacial cycles. High amplitude, short-term, fluctuations of small placoliths and F. profunda characterize the interval through MIS 24 to 22/21, suggesting strong instability in nutricline dynamics and surface water productivity. Principal Component Analysis and Shannon–Weaver indices (diversity and dominance) highlight significant shifts, mainly related to variations in the characteristics of surface waters. In both sites a minimum in diversity is recorded at MIS 22/21, corresponding to a maximum in the dominance of Reticulofenestra spp. at Site 607 and of Pseudoemiliania lacunosa at Site 967. Above MIS 21 the increase in abundance of various taxa (C. leptoporus, Umbilicosphaera spp., Syracosphaera spp., Rhabdosphaera spp., Oolithotus spp.) and a general increase in diversity are related to a distinct trend toward more stable and oligotrophic surface waters in contrast to the higher productivity and less stratified surface waters of the Early Pleistocene.     

Fingerprinting facies of the Tuff IF marker,with implications for early hominin palaeoecology,Olduvai Gorge,Tanzania

The top of Tuff IF marks the upper boundary of the Plio-/Pleistocene Bed I succession exposed in Olduvai Gorge, NE Tanzania, a tephrostratigraphic interval that is well known for remarkable Oldowan archaeological and vertebrate fossil assemblages, including early hominins. Geochemically, Tuff IF is characterized by a relatively consistent silica-undersaturated trachytic to phonolitic composition that relates both in terms of numerical ages (1.79 Ma) and compositional constraints to Olmoti volcano, located 22–38 km E of Olduvai Gorge.Measured Tuff IF sections are characterized by a thick unwelded pyroclastic flow in proximal settings and a succession of surges and ashfalls that interfingers with fluvio-lacustrine deposits of the Olduvai Basin in the medial to distal settings. Only in those areas with a relatively low topographic gradient, in distal reaches and beyond the toe of an Olmoti-sourced volcaniclastic fan, did the Tuff IF marker develop a typical threefold subdivision comprising: (1) primary surges and minor fallout, (2) reworked pumice units as lateral correlatives of proximally emplaced pyroclastic flows and (3) a succession of mass flows in conjunction with aeolian and fluvially reworked units.The pyroclastic marker unit is thus highly heterogeneous with regard to its vertical and lateral facies architecture and this has immediate effects on its preservation potential and in situ burial of fossils and stone artifacts. Even though the volcanically-related environmental perturbations were probably more severe at the eastern lake margin, the evidence for at least temporary freshwater sources and trees suggests environments conducive to hominin activities, but not during emplacement of Tuff IF pyroclastic flows and surges. This inference is supported by the presence of rich Oldowan stone artifact assemblages immediately preceding and following the deposition of Tuff IF, but only extremely sparse archaeological traces from one site in Tuff IF, restricted to the upper, fluvially reworked portion of Tuff IF.Tuff IF facies record the maximum of a regressive (drying) cycle that correlates with regional marine arid indicators. An ecological crisis covering ～ 2000–3500 a of time during Tuff IF deposition resulted not only from the lethal effects of explosive volcanism but also from its coincidence with a pronounced period of climate induced drought. These combined effects appear to have made at least the eastern basin uninhabitable by hominins and other vertebrates for most of the time during which Tuff IF accumulated.     

Pteropods as climatic indicators in quaternary sequences: A Lower-Middle Pleistocene sequence outcropping in Cava Puleo (Ficarazzi,Palermo, Italy)

Pteropod assemblages from a section outcropping at Cava Puleo (Ficarazzi, Palermo, type locality of the Sicilian stage) were studied for a paleoclimatic interpretation. The studied section directly overlies the subsurface Lower Pleistocene sequence.A curve of the absolute abundance of the subarctic species Limacina retroversa in the pteropod assemblage and a climatic curve based on the total amount of cumulative percentages of cold and warm pteropod indicators are proposed; the former shows a climatic trend in which a strong cold peak can be easily inferred at the top of the proposed Sicilian stratotype section. This drastic cold event is the first one recognizable in the local Lower Pleistocene sequence and may be correlated with the cold event recognized by Shackleton and Opdyke (1976) at the top of stage 22. The cold climatic fluctuation was abruptly followed by an internal with warm-temperate climate characterized by a tropical—subtropical assemblage.     

Middle Permian Ostracods from Tak Fa Limestone, Phetchabun Province, Central Thailand

This paper presents the first Permian ostracod fauna discovered in Thailand. The ostracods are recovered from the Tak Fa Limestone (Middle Permian) in Phetchabun province, central Thailand. The ostracods belong to eight genera and 15 species. Four species are newly described: Sargentina phetchabunensis nov. sp., Geffenina bungsamphanensis nov. sp., Reviya subsompongensis nov. sp. and Bairdia takfaensis nov. sp. The ostracod assemblages characterize a shallow marine, near shore environment at the time of deposition. Except for one species, which shows palaeobiogeographical links between Central Thailand and South China, all the other species are endemic.     

The Neogene Ostracod Genus <Emphasis Type="Italic">Advenocypris</Emphasis> from the Intermontane Depressions of the Southeastern Altai

This paper presents new data on ostracods of the genus Advenocypris. The distribution of these ostracods in the Neogene deposits of the intermontane depressions of Central Asia is analyzed. Species of this genus were selective regarding their habitats. This habitat specificity can be used to reconstruct the paleogeography of the depositional environments, origin and connections of water bodies in Central Asia. A new species of the genus Advenocypris is described. The previously known species of this genus are illustrated.     

Late Pliocene and Quaternary Eurasian locust infestations in the Canary Archipelago

Meco, J., Muhs, D.R., Fontugne, M., Ramos, A.J.G., Lomoschitz, A. & Patterson, D. 2010: Late Pliocene and Quaternary Eurasian locust infestations in the Canary Archipelago. Lethaia, Vol. 44, pp. 440–454. The Canary Archipelago has long been a sensitive location to record climate changes of the past. Interbedded with its basalt lavas are marine deposits from the principal Pleistocene interglacials, as well as aeolian sands with intercalated palaeosols. The palaeosols contain African dust and innumerable relict egg pods of a temperate‐region locust (cf. Dociostaurus maroccanus Thunberg 1815 ). New ecological and stratigraphical information reveals the geological history of locust plagues (or infestations) and their palaeoclimatic significance. Here, we show that the first arrival of the plagues to the Canary Islands from Africa took place near the end of the Pliocene, ca. 3 Ma, and reappeared with immense strength during the middle Late Pleistocene preceding MIS (marine isotope stage) 11 (ca. 420 ka), MIS 5.5 (ca. 125 ka) and probably during other warm interglacials of the late Middle Pleistocene and the Late Pleistocene. During the Early Holocene, locust plagues may have coincided with a brief cool period in the current interglacial. Climatically, locust plagues on the Canaries are a link in the chain of full‐glacial arid–cold climate (calcareous dunes), early interglacial arid–sub‐humid climate (African dust inputs and locust plagues), peak interglacial warm–humid climate (marine deposits with Senegalese fauna), transitional arid–temperate climate (pedogenic calcretes), and again full‐glacial arid–cold climate (calcareous dunes) oscillations. During the principal interglacials of the Pleistocene, the Canary Islands recorded the migrations of warm Senegalese marine faunas to the north, crossing latitudes in the Euro‐African Atlantic. However, this northward marine faunal migration was preceded in the terrestrial realm by interglacial infestations of locusts. □Locust plagues, Canary Islands, Late Pliocene, Pleistocene, Holocene, palaeoclimatology.     

The late Messinian Lago-Mare episode in the Mediterranean Basin: Preliminary report on the occurrence of Paratethyan ostracod fauna from central Crete (Greece)

In the Crete Island, late Messinian Lago-Mare facies are not well known. At present, the occurrence in Crete of the uppermost Messinian post evaporitic deposits is a matter of debate. According to several authors, the well-known late Messinian Lago-Mare facies does not occur in Crete. In this paper the preliminary results obtained from the biostratigraphical analysis of some sections sampled in the Messarà Plain will be shown. Nearby Faneromeni and Ano Akria villages, the Miocene/Pliocene boundary is well exposed. There, gypsum-bearing clay, laminated microcrystalline gypsum and gypsum-rudites characterize the evaporitic deposits of the Messinian stage. In these areas, above the Messinian evaporite, post-evaporitic fine-laminated polychrome clays, with intercalations of sandstones and conglomerates, have been found. In both the Faneromeni and Ano Akria area, the Pliocene grey clays and conglomerates rest unconformably on the uppermost Messinian post-evaporitic deposits. A 20 cm-spaced sampling has been performed in both the sections, for more than 100 samples collected. The results of the micropaleontological analysis performed on the Faneromeni and Ano Akria sections point to the occurrence of ostracod assemblages containing: Loxocauda limata (Schneider in Agalarova et al.), Loxocauda sp., Cytherura pyrama Schneider, Cyprideis anlavauxensis Carbonnel, Cyprideis agrigentina Decima, Amnicythere palimpsesta (Livental), Amnicythere propinqua (Livental), Amnicythere accicularia (Olteanu), Amnicythere costata (Olteanu), Amnicythere multituberculata (Livental), Amnicythere sp. D (Miculan in Bassetti et al.), Amnicythere sp. 2 Gliozzi and Grossi, Amnicythere sp., Euxinocythere (Maeotocythere) praebaquana (Livental in Agalarova et al.), Mediocytherideini indet., Pontoniella pontica (Agalarova), Camptocypria sp. 1 Gliozzi and Grossi, Caspiocypris sp., Zalanyiella venusta (Zalanyi), Tyrrhenocythere sp., Loxoconcha rhombovalis Pokorny, Loxoconcha eichwaldi Livental, Loxoconcha sp. A (Miculan in Bassetti et al.), Loxocorniculina djafarovi (Schneider in Suzin). In the analysed samples, reworked planktonic foraminifers and well-preserved charophyte gyrogonites have been also found. The ostracod assemblages found in the Messarà Plain belong to the Loxocorniculina djafarovi Zone (sensu Carbonnel, 1978), which characterizes the uppermost Messinian deposits of the whole Mediterranean Basin. At that time, the well-known Lago-Mare biofacies was also widespread on the Crete Island. The presence of Paratethyan ostracods in the post-evaporitic Messinian deposits of both Faneromeni and Ano Akria sections suggests that in the Crete Island the latest Messinian sedimentation took place in brackish water palaeoenvironments.     

Neogene stratigraphy,foraminifera, diatoms,and depositional history of Maria Madre Island,Mexico: Evidence of early Neogene marine conditions in the southern Gulf of California

Foraminifera and diatoms have been analyzed from an upper Miocene through Pleistocene(?) sequence of marine sediments exposed on Maria Madre Island, largest of the Trés Marias Islands off the Pacific coast of Mexico. The Neogene stratigraphic sequence exposed on Maria Madre Island includes a mid-Miocene(?) non-marine and/or shallow marine sandstone unconformably overlain by a lower upper Miocene to uppermost Miocene upper to middle bathyal laminated and massive diatomite, mudstone, and siltstone unit. This unit is unconformably overlain by lower Pliocene middle to lower bathyal sandstones and siltstones which, in turn, are unconformably overlain by upper Pliocene through Pleistocene(?) upper bathyal to upper middle bathyal foraminiferal limestones and siltstones. These beds are unconformably capped by Pleistocene terrace deposits. Basement rocks on the island include Cretaceous granite and granodiorite, and Tertiary(?) andesites and rhyolites. The upper Miocene diatomaceous unit contains a low diversity foraminiferal fauna dominated by species of Bolivina indicating low oxygen conditions in the proto-Gulf Maria Madre basin. The diatomaceous unit grades into a mudstone that contains a latest Miocene upper to middle bathyal biofacies characterized by Baggina californica and Uvigerina hootsi along with displaced neritic taxa. An angular unconformity separates the upper Miocene middle bathyal sediments from overlying lower Pliocene siltstones and mudstones that contain a middle to lower bathyal biofacies and abundant planktonic species including Neogloboquadrina acostaensis and Pulleniatina primalis indicating an early Pliocene age. Significantly, this Pliocene unit contains common occurrences of benthic species restricted to Miocene sediments in California including Bulimina uvigerinaformis. Pliocene to Pleistocene(?) foraminiferal limestones and siltstones characterize submarine bank accumulations formed during uplift of the Trés Marias Island area, and include abundant planktonic foraminifera such as Pulleniatina obliquiloculata and Neogloboquadrina duterteri. Common benthic foraminifera in this unit are indicative of upper bathyal water depths. The Neogene depositional history recorded on Maria Madre Island involves an early late Miocene subsidence event marking formation of the Trés Marias Basin with relatively undiluted diatomaceous sediment deposited in a low oxygen setting. Subsidence and deepening of the basin continued into the early Pliocene along with rapid deposition of terrigenous clastics. Uplift of the basinal sequence began in late Pliocene time accompanied by deposition of upper Pliocene-Pleistocene foraminiferal limestones on a rising submarine bank. Continued episodic uplift of the Neogene deposits brought the island above sea level by late Pleistocene time.     

Distribution and taxonomy of shallow marine Ostracods from Northern Socotra Island (Indian Ocean) - Yemen

Forty-seven species belonging to 30 genera of ostracods have been identified from Recent shallow marine sediments collected along the northern coastline of the island of Socotra (Indian Ocean). The systematics and distribution of these ostracods are discussed. Three genera, Loxoconcha, Bosasella, and Xestoleberis are found to have high species diversity. The species Loxoconcha ghardaqensis, Moosella striata are best documented in the Red Sea and Gulf of Aden while Kotoracythere inconspicua and Triebelina sertata were found to be the most widespread species. The fauna shows a close affinity to other ostracod assemblages of the Indo-Pacific region, East African coast and Red Sea.     

The geological record of a mid-Holocene marine storm in southwestern Spain

Integrated analysis of a 50-m long sedimentary core collected in the central part of the Odiel estuary (SW Atlantic coast of Spain) allows delineation of the main paleoenvironmental changes that occurred in this area during the Holocene. Eight sedimentary facies were deposited in the last ca. 9000 years BP, confirming a transgressive-regressive cycle that involves the transition from fluvial to salt marsh deposits with intermediate marine tidal deposits. A storm event is detected at ca. 5705 ¹⁴C years BP (mean calibrated age) with distinct lithostratigraphical, textural, geochemical, and palaeontological features.     

Viable Nematodes from Late Pleistocene Permafrost of the Kolyma River Lowland

We have obtained the first data demonstrating the capability of multicellular organisms for longterm cryobiosis in permafrost deposits of the Arctic. The viable soil nematodes Panagrolaimus aff. detritophagus (Rhabditida) and Plectus aff. parvus (Plectida) were isolated from the samples of Pleistocene permafrost deposits of the Kolyma River Lowland. The duration of natural cryopreservation of the nematodes corresponds to the age of the deposits, 30 000–40 000 years.