Upper Moscovian-middle Kasimovian conodonts (Pennsylvanian, Carboniferous) from the Las LLacerias Section (Cantabrian Zone, north Spain)

Las LLacerias Section in the western part of the Picos de Europa Unit (Cantabrian Zone) in northern Spain offers the best (essentially continuous) Upper Moscovian-Kasimovian succession in the Pennsylvanian of the Cantabrian Zone. The section consists almost entirely of limestones, and conodonts are scarce in general, but some Myachkovian levels are significantly more productive. Most specimens recovered are Pa pectiniform elements, and are generally well preserved. Idiognathodus, Streptognathodus, Gondolella, and Neognathodus are the most significant genera and Ubinates and Hindeodus are present. Idiognathodus is the dominant genus. Most of the idiognathodids differ morphologically from those elsewhere, and one, Idiognathodus covadongae, is formally recognized a new species. The presence of Idiognathodus eccentricus in the upper part of the Kreviakinian levels suggests a correlation with the lower Missourian of the United States. Neognathodus disappears in the upper part of the Myachkovian beds. Gondolella pohli was recovered from a short interval in the upper portion of the Myachkovian beds. Paleoecological conditions representing shallow, open, normal marine offshore deposits of the Idiognathodus-biofacies are interpreted for the lower portion of the Myachkovian interval.     

Jurassic biostratigraphy and paleoenvironmental evolution of the Malaguide complex from Sierra Espuña (Internal Betic Zone, SE Spain)

Jurassic studies in the Internal Zones of the Betic Cordillera are scarce since this zone is composed mainly of pre-Jurassic metamorphic rocks. Only the “Dorsal” and the Malaguide domains include fossiliferous Jurassic successions, as in Sierra Espuña (SE Spain), which is one of the bigger and well-exposed Jurassic outcrops of the Internal Zones. Collected Ammonite assemblages update and improve the precision of previous biostratigraphic data by the recognition of: the Domerian (= Upper Pliensbachian, in the Mediterranean Domain) Lavinianum (Cornacaldense Subzone), Algovianum (Ragazzoni, Bertrandi, Accuratum and Levidorsatum Subzones) and Emaciatum (Solare and Elisa Subzones) Zones; the Lower Toarcian Polymorphum and Serpentinum Zones; the Middle Toarcian, Bifrons and Gradata Zone; the Upper Toarcian Reynesi Zone; the Lower/Upper Bajocian, the Lower Callovian Bullatus and Gracilis Zones; the Middle/Upper Oxfordian Transversarium, Bifurcatus, Bimammatum and Planula Zones; and the Lower and Upper Kimmeridgian Platynota, Strombecki, Divisum and Beckeri Zones.The paleoenvironmental evolution of the Malaguide Jurassic at Sierra Espuña shows similarities with other Mediterranean Tethyan paleomargins. The biostratigraphic precision along with the litho- and biofacies analyses has enabled the interpretation that the Malaguide paleomargin evolved as a passive margin, developing shallow carbonate platforms, until the Domerian (Lavinianum Zone). Then, the platform broke up (Domerian, Lavinianum Zone-Upper Toarcian, Reynesi Zone) with the beginning of the rifting stage, beginning the development of horst-graben systems and the coeval drowning of the area. This stage ended in the upper Lower Callovian (Gracilis Zone) to the Middle Oxfordian (Transversarium Zone) interval, starting the drifting stage, which accentuated the horst-graben systems, leading to the deposition of condensed nodular limestones in the raised sea bottom.     

Conodont chronostratigraphical resolution and Declinognathodus evolution close to the Mid‐Carboniferous Boundary in the Barcaliente Formation type section,NW Spain

The Barcaliente Formation in its type section provides significant conodont occurrences in the Mid‐Carboniferous Boundary interval (between the Mississippian and Pennsylvanian sub‐periods). A sequence of Declinognathodus morphotype appearances (considered here as species) is recognized from the uppermost Serpukhovian to the lower Bashkirian. These morphotypes belong to Declinognathodus noduliferus (Ellison & Graves) sensu lato, the primary marker for the worldwide correlation of the Mid‐Carboniferous Boundary. Among them, D. inaequalis (Higgins) appears to have been the first species to occur at the Mid‐Carboniferous Boundary bed in the Arrow Canyon GSSP. A morphocline between D. bernesgae (Sanz‐López et al.) and D. inaequalis is studied here to identify the bed correlated with the GSSP. Other diagnostic first occurrences of conodonts (Rachistognathus minutus (Higgins & Bouckaert), D. noduliferus, D. lateralis (Higgins & Bouckaert), Idiognathoides asiaticus Nigmadganov & Nemirovskaya and I. corrugatus (Harris & Hollingsworth)) are evaluated as chrono‐markers throughout their worldwide distribution, particularly for the Eurasian faunas. The available secondary markers provide a better resolution and support chrono‐correlation in sections other than that at the GSSP. The worldwide first and late occurrences of studied taxa are considered within the background of the Mid‐Carboniferous Extinction Event and the conodont overturn, where crises progenitor Declinognathodus gave rise to members of the Family Idiognathodontidae. Firstly, progenitor taxa are good biostratigraphic tools, whereas local extinction of genera considered Mississippian in age and new taxa arising later in the post‐crises radiation suggest an early Bashkirian palaeogeography and climatic conditions confining temporarily the biogeographic distribution of conodonts.     

Life strategies of solitary undissepimented rugose corals from the upper member of the Picos de Europa Formation (Moscovian, Carboniferous, Cantabrian Mountains, NW Spain)

Rugose corals belonging to the orders Metriophyllina, Stereolasmatina and Plerophyllina have been identified in the upper member of the Picos de Europa Formation (Moscovian). Corals occur in crinoidal limestones containing common bryozoans. The coral assemblage shows a high diversity. Mode of preservation and spatial distribution of corals demonstrate close relationships with biogenic components such as crinoids, bryozoans, brachiopods and bivalves. The morphology of corals provides valuable data for identifying their life strategies, four of which have been identified: liberosessile with straight growth, liberosessile with curved growth, fixosessile with straight growth and fixosessile with curved growth. Most corals from the Picos de Europa Formation appear to have been fixosessile with straight growth; they attached themselves to bioclasts and subsequently developed radiciform processes (mainly talons) to remain straight.     

Pennsylvanian brachiopod,fish and conodont faunas from the Caliza Masiva (San Emiliano Formation) at the Mina Profunda area,Cantabrian Zone,NW Spain

A rock sample obtained from the Caliza Masiva of the San Emiliano Formation (Bashkirian–early Moscovian) in the Mina Profunda area (NE Villamanín) of the Bodón Nappe (Cantabrian Zone, NW Spain) has yielded numerous brachiopods and fish remains not frequently represented in the fossil record. The brachiopod assemblage comprises 13 taxa and is characterized by phosphatic (Langella, Orbiculoidea) as well as exceptionally preserved silicified calcitic elements (a small chonetid, Composita, Crurithyris, Lambdarina, and two minute terebratulids) as the main faunal components. Of special importance is the record of the microbrachiopod Lambdarina winklerprinsi nov. sp., which reduces the large Viséan–Upper Permian gap in the stratigraphic record of this genus. Conodont elements recovered from the same insoluble residue are indicative of the upper Bashkirian Idiognathoides sulcatus parvus Zone. The accompanying fish remains consist of chondrichthyan teeth and scales, an acanthodian scale and osteichthyan tooth-bearing bones, isolated teeth and isolated scales, representing the first Pennsylvanian ichthyoliths analyzed from the Cantabrian Zone. The limestone beds with selective silicification in the San Emiliano Formation provide an exceptional opportunity to improve our knowledge on the patterns of life diversity over geological time.     

Rugosochonetidae (Brachiopoda, Chonetidina) from the Carboniferous of the Cantabrian Mountains (N Spain)

An overview is given of the species belonging to the family Rugosochonetidae known from the Carboniferous of the Cantabrian Mts. Their distribution is compared with other occurrences in Eurasia and elsewhere. Subfamily and generic assignments are discussed in some detail. Comments on palaeogeographic and palaeoecological aspects of the rugosochonetid faunas are presented.     

New insights on the red alga Archaeolithophyllum and its preservation from the Pennsylvanian of the Cantabrian Zone (NW Spain)

The new species Archaeolithophyllum asymmetricum nov. sp., from the Bachende Formation (Pennsylvanian, Cantabrian Zone, NW Spain), is described herein using cathodoluminescence microscopy. Under plane-polarized light, A. asymmetricum occurs as elongate and arcuate sheets preserved as calcitic mosaics of tiny anhedral to subhedral crystals. Cathodoluminescence has revealed that skeletal walls are composed of dull-bright (locally bright) luminescent calcite that contrasts sharply with the nonluminescent cements filling the intraskeletal pores. Skeletal walls are currently composed of low-Mg calcite (0.5–2 mol % MgCO₃) with low Sr content (average 415 ppm). A. asymmetricum shows a strong asymmetry of the thallus organization. The internal tissue is well differentiated into a thick medullar hypothallus and a thin upper cortical perithallus, the latter being composed of nearly rectangular cells arranged in rows perpendicular to the external surface. Cell fusions commonly occur in the perithallial tissue whereas conceptacles exhibit a highly arched geometry lacking any preserved aperture. A. asymmetricum accumulations display a growth pattern similar to that reported from Late Paleozoic “phylloid algae”, and also resemble Miocene frameworks of the corallinacean Mesophyllum. These accumulations of A. asymmetricum formed micrite-rich bioherms with abundant shelter porosities, which are filled up with radiaxial-fibrous calcite (originally high-Mg calcite) and subsequent blocky spar. They constructed a rigid framework that was basically a combination of the foliaceous growth form, crust fusion and division, and synsedimentary marine cementation. Paleontological and sedimentological evidence suggests that A. asymmetricum thrived in an outer platform environment with relative quiet conditions. The exceptional preservation of these algae was favored by a rapid cementation of the intraskeletal pores under oxidizing conditions in a marine phreatic environment, protecting skeletons from early dissolution and recrystallization. Although the resulting neomorphic microsparite fabric suggests an aragonite precursor, the morphological similarities (especially reproductive organs) between Archaeolithophyllum and Recent calcitic corallinaceans, and the similar trace element composition of the algal thalli and the surrounding high-Mg radiaxial-fibrous cements, suggest that originally, Archaeolithophyllum was probably composed of high-Mg calcite. Based on the morphologic features, framework strategies (crust fusion and division) and growth modes, it is suggested that Archaeolithophyllum might be phylogenetically related to the modern coralline algae.     

滇西巍山地区上三叠统诺利阶三合洞组牙形石年代及沉积相分析*

滇西兰坪-思茅地块晚三叠世诺利期(Norian)发育一套海相碳酸盐岩沉积(三合洞组)。对巍山三合洞剖面进行了实测与采样, 分离了三合洞组碳酸盐岩中的牙形石, 经鉴定其种属为Epigondolella vialovi, Epigondolella uniformis和Epigondolella aff. triangularis, 时代为早诺利期(Lacian亚期)。通过野外剖面及室内显微薄片观察, 采用微相分析的方法对剖面三合洞组碳酸盐岩的微相类型和沉积环境进行研究, 将巍山三合洞剖面三合洞组沉积归纳为9种微相, 并根据微相特征结合野外宏观特征, 将三合洞剖面划分为3种沉积相类型, 即局限台地相、开阔台地相和台地边缘礁相。在剖面不同层位的碳酸盐岩中发现的热液矿物石榴子石及发黑的牙形石化石(CAI指数约为5), 表明该区曾遭受热液作用的影响, 可能与三合洞组沉积后大陆边缘裂谷下陷或板块拼合引起的热卤水上涌有关。     

Early Tremadocian (Ordovician) graptolite biostratigraphy and correlation

A revision of the early Tremadocian graptolites of the genus Rhabdinopora shows that Rhabdinopora proparabola from the Xiaoyangqiao section, Dayangcha, North China is the oldest species of the genus. Early Tremadocian species of Rhabdinopora can be differentiated easily by the construction of their nemata. The earliest species, Rhabdinopora proparabola, lacks a nema, while a multibranched nema is present in Rhabdinopora campanulatum (= Rhabdinopora parabola). The Rhabdinopora proparabola, Rhabdinopora campanulatum, Rhabdinopora flabelliformis (Anisograptus matanensis Biozone) and Rhabdinopora anglica biozones can be correlated worldwide. A short interval at the base of the Ordovician System does not contain any planktic graptolites.     

Re-interpretation of a Lower–Middle Cambrian West Gondwanan ramp depositional system: a case study from the Cantabrian Zone (NW Spain)

Detailed litho- and biofacies investigations of the Lower–Middle Cambrian carbonate Láncara Formation resulted in its subdivision into nine lithofacies types: (1) claystone, (2) recrystallized mudstone, (3) laminated mudstone with laminoid-fenestral fabrics, (4) stromatolite, (5) laminated aggregate grainstone, (6) non-laminated aggregate grainstone, (7) oolitic-bioclastic floatstone, (8) echinodermal packstone, and (9) bioclastic grainstone. The thicknesses of lithofacies 1–7 (lower member of the Láncara Formation) decrease from south to north. Lithofacies types 8–9 (upper member of the Láncara Formation) are characterized by similar thicknesses and low facies and faunal gradients and are thus indicative of deposition on a carbonate ramp. From palaeoecological, palaeo(bio)geographical, palaeomagnetic, and tectonic considerations, the depositional environment of the Láncara Formation is re-interpreted as an eastward/north-eastward sloping, low morphology carbonate ramp. The Cantabrian Zone, with a primary lateral extension of about 300 km, is further construed to be an element of a widespread and connected, discontinuous drowned Perigondwanan depositional system.     

New data (smaller foraminifers and correlation with depositional sequences) on the Las Llacerias section (Late Pennsylvanian,Cantabrian Mountains,NW Spain)

New sedimentological and paleontological information on the uppermost Moscovian and Kasimovian strata of the Las Llacerias section, a succession exposed in the Picos de Europa region (Cantabrian Mountains) that is considered to bear interest for the global correlation of the Upper Pennsylvanian subsystem, are presented. Based on sedimentological studies, three stratigraphic intervals can be established which record three successive episodes in the evolution of the carbonate platform. The study of the environmental evolution and sea-level fluctuations, as well as biostratigraphic fusulinoidean information, allow the correlation of this section with the synorogenic deposits of the Gamonedo-Cabrales area (northern Picos de Europa region). It is recognized that in the Las Llacerias strata, 7 of the 11 depositional sequences of the latter area are represented. The taxonomy and distribution of smaller foraminifers, a fossil group never studied before in this section, have been analysed. Data obtained show the presence of, at least, 30 genera. In some cases (Syzrania aff. bulbosa, Tezaquina, Mesolasiodiscus, Pseudotaxis and Hemidiscus), their record in the Las Llacerias section significantly extends the stratigraphic genus or species range. The potential role of Protonodosaria and Nodosinelloides species, as well as the acme of Hemigordius schlumbergeri for the correlation of the Kasimovian deposits is reinforced within this study.     

New species of Hispanomys (Rodentia,Cricetodontinae) from the Upper Miocene of Batallones (Madrid,Spain)

Material of Hispanomys (Rodentia, Cricetodontinae) is described from various localities at Batallones (MN10) (Madrid, Spain). All of it belongs to a single species, which differs from the other known species of the genus and a new taxon, Hispanomys moralesi sp. nov. , is created for it. The samples from the various localities show differences interpreted as being the result of slight age disparities amongst the different sites. Although they were previously thought to be coeval, Batallones 10 is probably older than Batallones 1, which is possibly older than Batallones 3. Hispanomys moralesi sp. nov. is characterized by several morphological features such as the lack of cingula and mesolophs, the presence of well‐developed ectolophs, four‐ or five‐rooted M1, short or absent mesolophids, and reduced and simplified M3. Hispanomys moralesi sp. nov. is a relatively derived species, the evolutionary stage of which is comparable to those of other members of the genus from the Upper Vallesian. © 2010 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 160 , 725–747.     

Miocene diatom biostratigraphy at ODP Sites 689, 690, 1088, 1092 (Atlantic sector of the Southern Ocean)

Four ODP sites located between 64°S and 41°S in the eastern Atlantic sector of the Southern Ocean were investigated to refine the Miocene diatom biostratigraphic zonation tied to the geomagnetic chronology. The Miocene diatom stratigraphy from two sites located on Maud Rise (ODP Leg 113) is revised considering the progress in diatom biostratigraphic research, diatom taxonomy and magnetostratigraphic age assignment during the past 10 years. A new diatom zonation was erected for Site 1092 (ODP Leg 177) located on Meteor Rise integrating a magnetostratigraphic interpretation of the shipboard data. This zonation was also applied to Site 1088 (ODP Leg 177) located on Astrid Ridge. The study is focused to Middle and Upper Miocene sequences. It reveals latitudinal differentiations in stratigraphic species ranges and species occurrence pattern that are related to latitudinal differences in surface water masses reflecting the climatic development of the Antarctic cryosphere. Considering the latitudinal differences two stratigraphic zonations are proposed that are applicable to the northern and southern zone of the Southern Ocean, respectively. The southern Southern Ocean Miocene diatom biostratigraphic zonation consists of 16 zones in which 11 represent new or modified zones. The northern biostratigraphic zonation contains 10 diatom zones allowing a stratigraphic resolution in the range of 0.2–2 Myr. This paper also includes the taxonomic transfer of seven Miocene diatom taxa from genus Nitzschia Hassal to Fragilariopsis Hustedt.     

Holoplanktonic gastropoda (Mollusca) from the Miocene of Cyprus: systematics and biostratigraphy

Abstract: Eleven randomly chosen outcrops in the Miocene Pakhna Formation of Cyprus were sampled for holoplanktonic Mollusca. Four species of Heteropoda were found, and 24 of Pteropoda, a substantial increase from the two species recorded until now from the Miocene of Cyprus. One pteropod species, Peracle charlotteae sp. nov. (Gastropoda, Pseudothecosomata), is introduced. Age assignments based on holoplanktonic molluscs for the 11 localities are as follows: Langhian (Alassa 1–4), (Serravallian?) Tortonian to Messinian (Episkopi 1), Tortonian (Agios Tychon, Tokhni and the Maroni Marlstone of Khirokitia 1–2) and Tortonian to Early Messinian (Episkopi 2). These age determinations in some cases are at odds with those from previous publications based on calcareous nannofossils and Foraminifera. The sediments underlying the Amathus Channel outcrop yielded insufficient fauna for definitive dating, but we suggest are younger than Late Serravallian. At some localities, particularly in the Alassa area, pteropod assemblages are strongly variable on a bed‐by‐bed basis, and this offers possibilities for future refined biostratigraphical interpretations. This is the first substantial holoplanktonic mollusc fauna described from the eastern Mediterranean basin and allows correlation with assemblages in the central Mediterranean and elsewhere.     

Lower Ovetian (Lower Cambrian) trilobites and biostratigraphy of the Pedroche Formation (Sierra de Córdoba, southern Spain)

The low Lower Cambrian rocks from the Sierra de Córdoba, which consist of well exposed mixed facies and abundant fossil assemblages showing long stratigraphic ranges throughout the Pedroche Formation, represent one of the best successions of this age in Europe. The fossil assemblages include diverse Ovetian archaeocyaths, trilobites, small shelly fossils, calcimicrobia, trace fossils and stromatolites. Trilobites are still poorly known, and thus they are the main objective of this work. The trilobites studied originate from three sections. At the Arroyo de Pedroche 1 section, cf. Bigotinella and Bigotinabivallata are replaced towards the top by Lemdadellalinaresae, Lemdadellaperejoni sp. nov. and, finally, by Eoredlichia cf. ovetensis. At the Arroyo de Pedroche 2 section, Lemdadellalinaresae is replaced by Lemdadellaperejoni sp. nov. and Eoredlichia cf. ovetensis, while at the Puente de Hierro section Lemdadellalinaresae, L. aff. linaresae and Serraniaverae occur together. These new biostratigraphic data confirm that the Pedroche Formation, originally defined as a repetitive sequence of four members, contains only two members. The new trilobite discoveries permit the first tentative correlation between the Ovetian of southern Spain and Lower Cambrian strata from the High Atlas (Morocco), Siberia, Antarctica and Carteret (France).     

The Upper Tremadocian (Ordovician) graptolite Bryograptus: taxonomy, biostratigraphy and biogeography

Abstract:  The taxonomy, biostratigraphical and palaeogeographical distribution of the Lower Ordovician graptolite genus Bryograptus is evaluated. Bryograptus is recognized as a distinct triradiate anisograptid with a multiramous, pendent rhabdosome. The species of the genus Bryograptus can be interpreted as shallow water faunal elements with a strongly limited biogeographical distribution to the Atlantic Faunal Realm. Bryograptus is restricted to a narrow interval in the Upper Tremadocian, the Bryograptus Biozone of Scandinavia and South America (Argentina), making it a taxon with a high potential for precise biostratigraphical correlations. The proximal end development can be used to differentiate the genus Bryograptus from other pendent multiramous graptoloid genera with a homoplastic rhabdosome development. Characteristics of the proximal end development and structure easily differentiate these genera in relief specimens, but not in flattened material.     

Upper Emsian Spinelloidea and Cyrtospiriferoidea (Brachiopoda, Spiriferidina) of the Cantabrian mountains (N Spain)

In the Cantabrian Mountains (NW Spain) a strong difference exists between Emsian articulate brachiopod species diversity compared to that of other remaining Devonian stages (169 Emsian species versus 210 species for the rest of the Devonian). Historical, paleogeographic and eustatic reasons are presented that could in part explain this numerical asymmetry. The Emsian stratigraphy of the Asturo-Leonian domain Emsian is briefly discussed and related to both global bio-events and eustatic and magnetosusceptibility events. Spiriferids are the most diversified Emsian brachiopod group (44 species). Despite this fact only nine of these spiriferid species have adequately been described and/or figured in recent times. This paper focuses on the Asturo-Leonian domain upper Emsian Spinelloidea and Cyrtospiriferoidea. Nine species (five new) are described and/or figured belonging to six genera (four new). The meaning of the term “crural plates” and its diagnostic value in the taxonomic characterization of the Family Spinellidae is discussed.     

Abandonment of traditional uses in mountain areas: typological thinking versus hard data in the Cantabrian Mountains (NW Spain)

Conservation policies of the European Nature 2,000 network reflect an overarching concern about alleged negative effects of abandonment of traditional uses. In particular, the abandonment of livestock herding is widely assumed to be responsible of biodiversity decreases through habitat homogenization. However, those negative effects of land abandonment on biodiversity are neither straightforward nor the repeatedly assumed land abandonment has been always supported by hard data. We analyzed the evolution of cattle densities in the Cantabrian Mountains (NW Spain) in the past 20 years, and its relation with the decline in the occupancy of capercaillie leks. Instead of the widely-assumed decrease of livestock numbers, which has been already incorporated into landscape and wildlife management, we found an actual increase in cattle numbers. Those cattle numbers were negatively related to the presence of an endangered, distinctive population of capercaillie, a bird considered an umbrella species in mountain forest ecosystems. Thus our data do not support the alleged role of free-ranging livestock in the conservation of biodiversity. We consider that typological thinking in the relationship of socio-economic changes and biodiversity conservation should be replaced by hard data and consideration of ecosystem naturalness.     

Palynological evidence of Early Carboniferous sedimentation in the Llanos Orientales Basin, Colombia

Early Carboniferous palynological assemblages from the SM-4 well located in the Llanos Orientales Basin constitute the only definitively geological evidence of Carboniferous strata in this Basin. Stratigraphically significant species include: Anapiculatisporites concinnus, Apiculiretusispora mutiseta, Grandispora spiculifera, Indotriradites dolianitii morphon, Spelaeotriletes pretiosus and Prolycospora rugulosa. The presence of scarce acritarchs indicates a shallow marine environment. A Tournaisian age, probably reaching the Viséan, is proposed for the interval 2010-2340 ft based on the presence of distinctive spore species with previous records in the Viséan and Tournaisian of Western Europe and Western Gondwana. This report increases the knowledge about the distribution and composition of the Early Carboniferous palynological assemblages in Northern Gondwana.