Biostratigraphic Interpretations Research Articles

Biostratigraphic Interpretation of Lutut Beds, Kerek Formation, Based on Foraminifera Fossils

Lutut Beds are the sandstone beds exposed in the northwest margin of Kendeng Basin, which contain abundant metamorphic-quartz grains, frequent recycled sedimentary quartz, and reworked bioclasts. Lutut Beds are not shown on the regional geological map and are often neglected in determining the geological history of Kendeng Basin. However, they have significant roles because it was deposited on the basin edge, which may carry important keys. This study aims to discover the larger and smaller foraminifera fossils contained in the Lutut Beds. Outcrop samples were collected in Kali Lutut and its surrounding area, including Lutut Beds and its overlying layers. Larger foraminifera was identified within 3 of 11 thin sections, mostly of Order Rotaliida, which occur as reworked bioclasts. The smaller foraminifera was barely found in most samples except for the samples from the overlying layers of Lutut Beds. The study reveals that Lutut Beds were deposited during Early to Middle Miocene, marked by the occurrence of Miogypsina sp. and Miogypsinoides sp. and also contains reworked Eocene – Early Oligocene larger foraminifera such as Nummulites sp., Discocyclina sp., and Dictyoconus sp. Besides, the overlying layer of Lutut Beds is identified to be deposited in the Middle Miocene to Pliocene based on the occurence of smaller planktonic foraminifera, Sphaeroidinella subdehiscens. The bathymetric interpretation based on smaller benthic foraminifera showed that Lutut Beds were deposited in the upper-middle bathyal zone. We also believe that the larger benthic foraminifera fossils in Lutut Beds were transported along the slope from its original life position. Accordingly, it is considered as allochthonous fossils.

The Baltoniodus navis Zone in the Gualcamayo Formation (Middle Ordovician), Central Precordillera, Argentina

We study the conodont fauna and its biostratigraphy recorded in the lower 3 m of the Gualcamayo Formation at the Potrerillos Creek section, northern Central Precordillera of Argentina. The analysis of two conodonts samples from levels of biostratigraphic interest, allowed us to identify 828 conodonts, assigned to 31 genera and 42 species. The recognition of Baltoniodus cf. triangularis (Lindström), Tripodus laevis s.l. Bradshaw, Baltoniodus navis (Lindström), and abundant elements of Paroistodus originalis (Sergeeva) allowed us to determine the lower part of the Baltoniodus navis Zone in the basal section of the Gualcamayo Formation. This allows us to reconsider previous biostratigraphic interpretations that assigned the lower 10 m of the Gualcamayo Formation to the Baltoniodus triangularis-Tripodus laevis Zone, to be reassigned to the Baltoniodus navis Zone. The lower part of the Baltoniodus navis Zone recognized in the present work correlates elsewhere in Argentina (Puna, Famatina, and Precordillera), as well as in China and Sweden with the lower Baltoniodus navis Zone, whereas it correlates with the upper part of the Microzarkodina flabellum-Tripodus laevis Zone in North America. Also correlates to the Isograptus maximus Zone. The occurrence of abundant conodonts representative of the Baltoniodus navis Zone in the Potrerillos Creek section, makes it suitable for further studies of a biostratigraphic interval that is underrepresented in most published sections of the Precordillera. In addition, we analyzed the preservation and CAI of the conodont elements recovered, these have a CAI of 2.5–3, indicating burial paleotemperatures of 85°−200 °C. Most gracile elements show a lower CAI (2.5) than the robust ones (CAI 3). Most elements present silica crystals attached to surfaces and the basal cavity, while few elements have recrystallized surface lamella. These fossilization features could be attributed to diagenetic effects related to intense tectonic deformation.

An endemic conodont fauna of Darriwilian (Middle Ordovician) age from the Santa Gertrudis Formation, southwestern Gondwanan margin and its paleobiogeographic relationships

A large collection of conodonts (over 4200 elements) from the Santa Gertrudis Formation of the Cordillera Oriental, NW Argentina, is analyzed. The mostly endemic fauna of this unit and the lack of index species require complex taxonomic and biostratigraphic interpretations. We determined new species apparatuses by reviewing previous literature with a different taxonomic approach: Erismodus saltaensis n. sp., Erraticodon aldridgei n. sp., Gallinatodus elegantissimus n. gen. et sp., Pyramidens cactus n. gen. et sp., P. spinatus n. gen. et sp., Zentagnathus gertrudisae n. sp. Although the lack of key conodont species for intercontinental correlation precludes biostratigraphic assignment to a particular biozone, the overlapping ranges of recorded species restrict the age range to the upper Lenodus variabilis, Yangtzeplacognathus crassus and the lower Eoplacognathus pseudoplanus zones, of middle Darriwilian age (Dw2, Middle Ordovician). The depositional environment of the Santa Gertrudis Formation is primarily a shallow inner platform influenced by waves but not by storms; its paleogeographic location in mid-high latitudes exerts important control over the conodont biofacies, similar to the Arabian Darriwilian faunas of the Gondwanan margin. A narrow marine seaway along the suture zone connecting East and West Gondwana is proposed to explain the evolution of lineages of shallow cold-water conodont faunas from the Middle Ordovician onwards.

Quantitative Biostratigraphic Analysis and Age Estimates of Middle Cretaceous Sequences in The Baltimore Canyon Trough, Offshore Mid-Atlantic U.S. Margin

ABSTRACT We applied quantitative methods to previously published biostratigraphic data from the Baltimore Canyon Trough (offshore of the Mid-Atlantic U.S.A.) to provide an improved chronostratigraphic framework for Cretaceous sequences. Here, we successfully used graphic correlation of 228 planktonic foraminifera, nannofossil, and palynological events spanning 22 wells to define assemblage and interval zones as well as major paleoenvironmental changes in the Dawson Canyon, Logan Canyon (three sequences), and Missisauga Formations (two sequences, undifferentiated here). Ranking and scaling techniques were not successful because of the of the limited number of usable biostratigraphic markers. The ages of the sequences previously identified using well logs and seismic profiles were temporally constrained based on chronostratigraphically significant biostratigraphic markers that we identified: the late Cenomanian to Turonian DCx sequence (Rotalipora cushmani and Thalmanninella greenhornensis); the early Cenomanian LC1 sequence; the middle and late Albian LC2 sequence (Braarudosphaera africana, Planomalina buxtorfi, and Spinidinium vestitum); the late Aptian LC3 sequence (Cyclonephelium tabulatum); and the early Aptian to Barremian Missisauga sequences (Aptea anaphrissa, Pseudoceratium pelliferum, and Muderongia simplex). These five biostratigraphic associations are correlated with six prominent seismic reflectors and sequence boundaries that can be traced across the basin. Duration of hiatuses associated with these sequence boundaries are uncertain, though our Monte Carlo analysis allows extraction of age estimates from broad and sometimes contradictory ranges and suggests correlation of hiatuses with global sea-level falls. Together, these seismic and biostratigraphic interpretations can be applied (1) to evaluate reservoir continuity and the viability of offshore carbon storage reservoirs in the Baltimore Canyon Trough, (2) to better define the tectonostratigraphic evolution of the basin, and (3) to contribute to the understanding of regional and global variations in Cretaceous sea level.

VALANGINIAN RADIOLARIANS OF NE SARDINIA (ITALY) IN THE FRAME OF THE WEISSERT EVENT

This article presents the very rich radiolarian fauna from the S’Ozzastru section of the Siniscola Marl crop-ping out in the northern part of Mt Albo massif (NE Sardinia, Italy). The formation was ascribed to the lower part of the upper Valanginian on the basis of the ammonite fauna indicating the Verrucosum Zone and the nannofossil con-tent suggesting the Zone NK3. Due to the scarcity of pantanelliids and especially of the absence of Cecrops septem-poratus, radiolarian marker of the upper Valanginian, radiolarians can only indicate a Valanginian age. Investigations for integrated litho-, bio-, and chemostratigraphy allowed the identification of the Valanginian Weissert Oceanic An-oxic Event (OAE), testified by a positive carbon isotope excursion (CIE) with values up to 2.98 ‰. Radiolarian study includes not only a determination of the species for biostratigraphic interpretations, but also a revision of the system-atics of the radiolarians occurring in the section. One new family (Crococapsidae), 3 new genera (Apiaromitra, Mi-crosandwichia and Ocellicapsa) and 43 new species are erected. The fauna has some elements in common with the Valanginian faunas from the Mediterranean area and many more with those from Japan, proving a wide circulation between the western and eastern Tethys.

First population-level study of the ammonite genus Hildoglochiceras Spath, and the Lower Tithonian record of the Hildoglochiceras Horizon in the Kachchh Basin, India

A Hildoglochiceras-rich horizon is reported from a thin carbonate intercalation within the siliciclastic Upper Jurassic Jhuran Formation of the Jara Dome, western Kachchh Mainland. The Hildoglochiceras specimens have been used for the first population-level study of the genus based on a multivariate analysis. High phenotype instability in the large sample confirms the occurrence of transient forms between morphospecies. Key morphological traits for interpreting Hildoglochiceras are stated, and the morphospecies Hildoglochiceras kobelli (Oppel) and H. kobelliforme (Bonarelli) are interpreted as a dimorphic pair. The ammonite-rich level is interpreted as a Hildoglochiceras Horizon, which is related to a transgressive pulse and maximum flooding zone interrupting largely restrictive conditions for ammonites. The endemic character of Hildoglochiceras is confirmed and related to its environmental restriction to shelf areas on the palaeomargins of the Trans-Erythraean Trough. A comprehensive review of biostratigraphic interpretations of Hildoglochiceras shows the influence of natural and experimental forcing factors. The uppermost Kimmeridgian to lowermost Upper Tithonian interval is the widest biostratigraphic range assumable for Hildoglochiceras based on existing reports, but most probably it was restricted to, or at least better represented in, Lower Tithonian horizons. The Hildoglochiceras Horizon described here is correlated with a lower part of the Albertinum/Darwini Zone in the Secondary Standard Scale for ammonite-based bio-chronostratigraphy in European and West-Tethyan areas. According to the current state of knowledge, a local rather than wide regional significance is favoured for Hildoglochiceras records before its significance for precise correlation across the Trans-Erythraean Trough.

COMMENTS ON “BIOSTRATIGRAPHIC INVESTIGATION AND DEPOSITIONAL MODEL OF THE LATE THANETIAN RANIKOT AND THE YPRESIAN LAKI FORMATIONS IN THE SUBSURFACE OF THE SOUTHERN INDUS BASIN, PAKISTAN”

This note aims to criticize the identification of key larger benthic foraminifera (LBF) at species or genus rankand the biostratigraphic interpretations. The species figured in the under-discussion paper are largely misidentified. The authors did not follow the fundamental principles for the identification of the LBF. Usingthe misidenti fied species led to the incorrect establishment of the shallow benthic zones (SBZ). Consequently,pro vided the wrong biostratigraphic age to the Lower Eocene succession of the Southern Indus Basin. Themicropaleontological analysis coupled with microfacies description that suffers from the misidentification of most key-index taxa is useful for the definition of a precise depositional environment. The stratigraphic nomenclature is also wrong throughout the article where the authors confused the Group and Formation. The italic and non-italic protocols for the species and genus rank are also wrong throughout the article. Therefore, this note highlights the errors which have been made regarding the age, depositional model, and nomenclature of the Lower Eocene succession of the Southern Indus Basin.

Brachiopods from the Río del Peñón Formation. Río Blanco Basin, Upper Palaeozoic of Argentina.

This paper reviews the brachiopod fauna from the Ríoo de! Peñón Formation, Río Blanco Basin, Upper Palaeozoic of La Rioja province, Argentina. Traditionally, this unit was referred to the Carboniferous, however the braquiopod fauna here studied suggests a new biostratigraphical interpretation, indicating an age range from the latest Carboniferous to Early Permian. Three different brachiopod assemblages can be identified in the section: Assemblage I, from the lower member, includes Streptorhynchus? sp., Dyschrestia? sp., Costatumulus sp. A, Trigonotreta sp., Spiriferellina sp., Orbiculoidea sp., and unidentifiable productids and strophomenids.Assemblage II, from the middle member, includes Tivertonia jachalensis (Amos), Kochiproductus riojanus (Leanza), Costatumulus sp. B, Trigonotreta riojanensis (Lech and Acefiolaza) and Orbiculoidea sp. Assemblage III, from the highest part of the middle member, includes Neochonetes pegnonensis sp. nov., Costatumulus sp. C, Rhynchopora sp., Septosyringothyris jaguelensis Lech, and Orbiculoidea sp. These brachiopod assemblages demonstrate close affinities with faunas from the lower Permian of Western Australia and India. Affinities with faunas from Peru and Texas are less close.

Late Eocene to early Oligocene calcareous nannofossil biostratigraphy of the Cerro Colorado Formation, Austral basin, Argentina

This paper documents calcareous nannofossil assemblages and the bioevents recorded in the Austral basin of Tierra del Fuego, Argentina. Fifty samples from the type section of the Cerro Colorado Formation were analyzed. Nannoflora is moderately preserved and indicates a late Eocene to early Oligocene age for sedimentary rocks of this formation. Biostratigraphic results are based on distribution patterns of calcareous nannofossils assemblages, permitting comparison with the Southern Ocean zonations and some correlations with standard schemes. Our biostratigraphic interpretation shows an almost complete stratigraphic section spanning from the Priabonian to Rupelian Stages and calcareous nannofossil Chiasmolithus oamaruensis to Blackites spinosus zones, or the low latitude zones of Martini NP18 to NP21. The oldest fossiliferous rocks from the type locality of the Cerro Colorado Formation contain Chiasmolithus oamaruensis indicating nannofossil Zone NP18. The Eocene/Oligocene boundary was placed between the last occurrence (LO) of Reticulofenestra oamaruensis and the increasing in abundance (IB) of Reticulofenestra daviesii. Samples taken from the top of the section belong to the Estancia María Cristina Beds have Cyclicargolithus abisectus. During the late middle to late Eocene a hiatus is suggested between the Cerro Colorado and Leticia formations evident by a 39 Ma detrital zircon age dating, and the first occurrence (FO) of Dictyococcitesbisectus. Furthermore, the presence of C. abisectus in the Estancia María Cristina Beds suggests an unconformity with the underlying Cerro Colorado Formation as previously inferred by stratigraphic relationships.

Marine influence in western Amazonia during the late Miocene

The dynamic environments of western Amazonia during the Neogene (23 to 2.58 million years ago [Ma]) included continental-scale wetlands that were episodically influenced by marine incursions originating from the Caribbean. The nature and frequency of such events is highly debated, with a general consensus on short events during the early (23 to 16) and middle (16 to 11.6 Ma) Miocene. However, scattered evidence for more events up until the late Miocene (11.6 to 5.3 Ma) exists. Based on a palynological analysis of borehole 1-AS-9-AM from the Solimões Formation (western Amazonia, Brazil), we provide further support for late Miocene marine influence in the region. Comparisons with other sites in the Solimões Basin indicate an age of earliest Tortonian (~11–10 Ma) for an assemblage with foraminiferal linings, acritarchs and dinocysts, totalling ~17.3% of the palynological count ( n = 374 palynomorphs) at 34.10 m of depth. This is the topmost sample with a significant amount of marine indicators and its age is consistent even when different biostratigraphic interpretations are appreciated. Our data and comparisons also show that a larger proportion of sediments of the Solimões Formation should be placed within the late middle to early late Miocene. Our reconstruction of the Solimões deposits in the early Tortonian indicates intermintent low salinity regimes and a persistent connection with the paleo-Orinoco drainage until the closure of this connection in the late Miocene to Pliocene times. • New pollen data is presented from a borehole (1-AS-9-AM) in western Amazonia. • Graphic correlation was applied with two nearby sites, ages found from middle to late Miocene. • A thicker late Miocene section than previously interpreted is suggested. • A marine assemblage (~17% of the palynological count) at 34 m is composed of foraminiferal linings, dinocysts and acritarchs. • Regional comparisons support an early Tortonian episode of marine influence in a wide geographical area in western Amazonia.

New biostratigraphic interpretation of the Middle Miocene (Badenian) transgression in the southern margin of the Pannonian Basin (Hrvaćani, northern Bosnia, Central Paratethys), based on the fossil assemblages

New biostratigraphic interpretation of the Middle Miocene (Badenian) transgression in the southern margin of the Pannonian Basin (Hrvaćani, northern Bosnia, Central Paratethys), based on the fossil assemblages

Palynological investigations reveal Eemian interglacial vegetation dynamics at Spiezberg, Bernese Alps, Switzerland

Interglacial pollen records are valuable archives of past vegetation dynamics and provide important information about vegetation responses to different-than-today climates. Interglacial pollen archives pre-dating the Last Glacial Maximum (LGM) are scarce on the Swiss Plateau in contrast to the many available Late Glacial and Holocene records. This is mainly due to the rapidly changing palaeo-environmental conditions throughout the Quaternary and the low preservation potential of material suitable for palynological investigations. The Spiezberg site offers a palynological record situated most proximal to the Alps in Switzerland. Previous investigations tentatively assigned this record to the Eemian interglacial (MIS 5e). We have conducted additional pollen analytical investigations to increase the quantity of pollen information. Besides biostratigraphic interpretations, we use numerical methods such as distance analysis (distantia) and ordination techniques (PCA) to evaluate the similarities and differences between the Spiezberg record and its geographically and chronostratigraphically closest physically dated (U/Th, luminescence) analogues from the Eemian (MIS 5e) and Meikirch 3 (MIS 7a) interglacials. Our palynological investigations reveal the predominance of closed temperate forests with abundant fir (Abies) and spruce (Picea) as well as evergreen broad-leaved taxa (e.g. Hedera). The attribution to the Eemian interglacial relies on the observation of very rare beech (Fagus) occurrences, a phase with prominent yew (Taxus) and the unimportance of hornbeam (Carpinus), all of which are typical Eemian features on the Swiss Plateau. An Eemian age is supported by the numerical comparison with the Beerenmösli (MIS 5e) and Meikirch 3 (MIS 7a) reference records. Furthermore, the Picea, Taxus and Fagus dynamics observed on the Swiss Plateau during the Eemian are in excellent agreement with vegetational patterns observed elsewhere in Central Europe. Surprisingly, Carpinus was almost absent on the Swiss Plateau during the Eemian, whereas it was a major component of the forest at other European sites with a similar elevation as Spiezberg. We explain this by environmental conditions and the strong competition with Abies alba. In particular, considering the European Eemian vegetation history and the results of our reconstructions from the Swiss Plateau, we find that Abies alba was a highly competitive tree under natural warmer-than-today conditions. This finding provides further evidence that Abies alba may benefit from future climate warming.

Stratigraphic and sedimentological aspects of the worldwide distribution ofApectodiniumin Paleocene/Eocene Thermal Maximum deposits

AbstractThe Paleocene/Eocene Thermal Maximum (PETM) is characterized by pronounced global warming and associated environmental changes. In the more-or-less two decades since prior regional syntheses of Apectodinium distribution at the PETM, extensive biological and geochemical datasets have elucidated the effect of rising world temperatures on climate and the biome. A Carbon Isotope Excursion (CIE) that marks the Paleocene/Eocene Boundary is associated with an acme of marine dinocysts of the genus Apectodinium in many locations. Distinctive foraminiferal and calcareous nannofossil populations may also be present.For this updated, dinocyst-oriented view of the PETM, data from worldwide locations have been evaluated with an emphasis on stratigraphic and sedimentological context. What has emerged is that a change in lithology is common, often to a distinctive siltstone or claystone unit, which contrasts with underlying and overlying lithotypes. This change, present in shallow marine/coastal settings and in deep-water turbidite deposits, is attributed to radical modifications of precipitation and erosional processes. An abrupt boundary carries the implication that some time (of unknowable duration) is potentially missing, which then requires caution in the interpretation of the pacing of events in relation to that boundary. In most instances an ‘abrupt’ or ‘rapid’ CIE onset can be attributed to a data gap at a hiatus, particularly in shallow shelf settings where transgression resulted from sea-level rise associated with the PETM. Truly gradational lower boundaries of the PETM interval are quite unusual and, if present, are poorly known so far. Gradational upper boundaries are more common, but erosional upper boundaries have been reported.Taxonomic changes have been made to clarify identification issues that have adversely impacted some biostratigraphic interpretations. Apectodinium hyperacanthum has been retained in Wetzeliella, its original genus. The majority of specimens previously assigned to Apectodinium hyperacanthum or Wetzeliella (Apectodinium) hyperacanthum have been reassigned to an informal species, Apectodinium sp. 1. Dracodinium astra has been retained in its original genus as Wetzeliella astra and is emended.

Application of sequence stratigraphy for an enhanced hydrocarbon reservoirs correlation in \u201cOSP\u201d field Niger Delta, Nigeria

The cost of drilling exploration and production wells is high and the price of crude oil in the capital market is fluctuating, therefore, there is the need to mitigate the risk of improper investigation of time/age-dependent reservoir rocks continuity within a field. Sequence stratigraphic analysis was carried out in OSP field with the aim of identifying and correlating hydrocarbon reservoirs that are deposited contemporaneously. Key stratigraphic surfaces (maximum flooding surfaces and sequence boundaries) were interpreted from biostratigraphic, well log and seismic data. Biostratigraphic interpretation subdivide the study area into three floral subzones—P780, P820 and P830. Three maximum flooding surfaces dated 10.4 Ma, 9.5 Ma and 7.4 Ma and four sequence boundaries dated 10.6 Ma, 10.35 Ma, 8.5 Ma and 6.7 Ma were identified. Three depositional sequences (sequences 1–3) were identified from the integration of the biostratigraphic, well log and seismic data. The identified key stratigraphic surfaces and depositional sequences were employed in the delineation and correlation of the hydrocarbon reservoirs which were found to fall within the highstand and lowstand systems tracts. Sequence stratigraphic correlation technique aided the local arrangement and geometries of reservoirs within the field and in locating potential reservoirs.

Comments on “Facies modeling of synchronous successions – A case study from the mid-cretaceous of NW Zagros, Iran” by Shoghi et al., J. Afr. Earth Sci., 162 (2020) 103696

A number of micropalaeontological identifications and biostratigraphic interpretations made in a recent paper on mid-Cretaceous of the Iranian Zagros are questionable, and in many cases, can be shown to be erroneous. This in turn casts doubt on correlations and sequence stratigraphic interpretations presented in that paper, as the basis for these is undermined.

Eocene larger benthic foraminifera (alveolinids, nummulitids, and orthophragmines) from the eastern Alborz region (NE Iran): Taxonomy and biostratigraphy implications

Shallow marine Eocene successions are described and illustrated with major focus on the systematics and biostratigraphic interpretation of larger benthic foraminifera in two stratigraphic sections (Mojen & Kalateh) of the Ziarat Formation from the eastern Alborz zone (Iran). Based on the larger benthic foraminifera assemblages, six shallow benthic zones (SBZ8-SBZ10 and SBZ16?-SBZ17-SBZ18b) during the middle Ilerdian-early Cuisian and Late Lutetian?-Bartonian interval are identified for the first time. The Mojen section is mainly composed of Alveolina horizons as index markers, such as Alveolinadecipiens (Schwager), A. tumida (Hottinger), A. ilerdensis (Hottinger), A. sp. cf. A. ilerdensis, A. laxa (Hottinger), A. citrea (Drobne), A. trempina (Hottinger), A. fornasinii (Checchia-Rispoli), A. canavarii (Checchia-Rispoli), A. cf. canavarii and A. aff. cayrazensis, which are consistent with the SBZ8 to SBZ10 interval, whilst the exact age of the top of the interval was not distinctly recognizable. The studied interval of the Kalateh section was assigned to the SBZ16?-SBZ17-SBZ18b with identifications of larger hyaline-lamellar foraminifera represented by Nummulites cf. deshayesi, N. lyelli (D’Archiac & Haime), Orbitoclypeus zitteli (Checchia-Rispoli) and Asterocyclina stellastella (Gümbel).

A new genus of Proterotheriinae (Mammalia, Litopterna) from the Pleistocene of Uruguay

ABSTRACTWe describe a new genus and species of Proterotheriinae from the Pleistocene of Uruguay. Several taxonomic, biostratigraphic, paleoecological, and paleoenvironmental analyses and interpretations have been performed in a detailed study of the Litopterna (Mammalia, ‘Meridiungulata’) of Uruguay. The Proterotheriidae is the most diverse family of the Litopterna. In Uruguay, the record of the Proterotheriidae, although in many cases fragmentary, includes interesting specimens in particular contexts and different ages in the late Oligocene–late Pleistocene. The aim of this work is to reassess the specimens primarily assigned four decades ago to ‘Licaphrium’ aff. floweri, redescribing them, evaluating their taxonomic status in the context of the Proterotheriidae, and establishing the characters that allow the determination of this taxon as a new genus and species of Proterotheriinae: Uruguayodon alius. We redescribe two specimens of this new taxon, which include dental and postcranial remains. The diagnostic element is the last lower molar, which shows, among other characters, paraconid and paralophid in a very lingual position, smoothed metaflexid, and absence of entoflexid. The individuals were excavated from a sandy level of the San José Member of the Raigón Formation, a unit that has an endemic fauna, a pattern discussed here in a paleogeographic framework. The provenance of the analyzed specimens from Pleistocene layers is indicated by mammalian content and absolute ages, which support the presence of another genus of Proterotheriidae surviving into the Quaternary, in addition to Neolicaphrium recens.

The Carnivora (Mammalia) from the middle Miocene locality of Gra\u010danica (Bugojno Basin, Gornji Vakuf, Bosnia and Herzegovina)

The Carnivora (Mammalia) yielded in the coal mine Gračanica in Bosnia and Herzegovina are composed of the caniform families Amphicyonidae (Amphicyon giganteus), Ursidae (Hemicyon goeriachensis, Ursavus brevirhinus) and Mustelidae (indet.) and the feliform family Percrocutidae (Percrocuta miocenica). The site is of middle Miocene age and the biostratigraphical interpretation based on molluscs indicates Langhium, correlating Mammal Zone MN 5. The carnivore faunal assemblage suggests a possible assignement to MN 6 defined by the late occurrence of A. giganteus and the early occurrence of H. goeriachensis and P. miocenica. Despite the scarcity of remains belonging to the order Carnivora, the fossils suggest a diverse fauna including omnivores, mesocarnivores and hypercarnivores of a meat/bone diet as well as Carnivora of small (Mustelidae indet.) to large size (A. giganteus). Faunal similarities can be found with Prebreza (Serbia), Mordoğan, Çandır, Paşalar and Inönü (all Turkey), which are of comparable age. The absence of Felidae is worthy of remark, but could be explained by the general scarcity of carnivoran fossils. Gračanica records the most eastern European occurrence of H. goeriachensis and the first occurrence of A. giganteus outside central Europe except for Namibia (Africa). The Gračanica Carnivora fauna is mostly composed of European elements.

Eocene to Oligocene dinoflagellate cysts from the Tattofte section, western External Rif, northwestern Morocco: Biostratigraphy, paleoenvironments and paleoclimate

The palynological analysis of the Eocene–Oligocene succession from the Tattofte section in the western External Rif (northwestern Morocco) reveals the presence of well-preserved and diverse assemblage, rich in dinoflagellate cysts (dinocysts). Qualitative analyses, especially of the dinocysts, differentiate the individual stages of the deposits, while quantitative analyses permit paleoenvironmental and paleoclimatic interpretations. We assign the lower part of the Tattofte section to the Middle Eocene (Lutetian and Bartonian) and its upper part to the Upper Oligocene (Chattian), and define a hiatus spanning the Late Eocene (Priabonian) and Early Oligocene (Rupelian). The dinocyst marker events used for the biostratigraphic interpretations include the first and last occurrences of marker species, such as Batiacasphaera compta, Castellodinium compactum, Cerebrocysta bartonensis, Distatodinium biffii, Distatodinium paradoxum, Distatodinium ellipticum, Enneadocysta arcuata, Homotryblium floripes, Hystrichokolpoma bullatum, Impagidinium velorum, Lentinia serrata, Pentadinium imaginatum, Rhombodinium spinula, Saturnodinium perforatum and Ynezidinium brevisulcatum, as well as the Chiropteridium spp. acmes. And we equate the Chattian with the dinocyst Distatodinium biffii Zone of Brinkhuis et al. (1992).Changes in the relative abundances of selected dinocyst groups, spores and pollen lead to the distinction, from oldest to youngest, of four marine environments: 1) marginal marine to coastal inner neritic under relatively warm-water during the Middle Eocene; 2) outer neritic to oceanic during a transgressive regime in the early Chattian; 3) fluctuating restricted to open marine in the middle Chattian; and 4) shallow coastal to open marine due to sea-level fall at the top of the section in the latest Chattian, suggested by the Chiropteridium spp. acmes.The acmes of selected thermophilic dinocyst taxa, such as Polysphaeridium spp. and Homotryblium spp. suggest warm water marine conditions, which may be related to the Middle Eocene climatic optimum (MECO) and Late Oligocene warming.

Palynomorphs from the Devonian Talacasto and Punta Negra Formations, Argentinean Precordillera: New biostratigraphic approach

Marine and terrestrial palynomorphs from the Loma de los Piojos section of the Precordillera Basin, western Argentina, were analyzed. The studied section embraces the upper part of the Lower Devonian Talacasto Formation and the whole Lower-Middle? Devonian Punta Negra Formation, which constitute the Gualilán Group. Terrestrial palynomorphs dominate the Talacasto Formation whereas marine palynomorphs dominate the Punta Negra Formation. Even though palynomorphs are scarce, poorly preserved, and marked by low diversity, they enable, together with previous palynological data, a new biostratigraphic interpretation for the Devonian units of the Gualilán Group. In addition, an age reassessment of the guide horizon of Keidel (1921), and a correlation of sections from different parts of the basin are provided. Based on palynological data, the age of the Talacasto Formation is constrained to the Lochkovian-late Pragian and the age of the Punta Negra Formation is now considered to be restricted to the late Pragian-Emsian, although a younger age for the uppermost part of Punta Negra is possible.