Cieneguiticeras, a new genus of Tithonian oppeliids (Ammonoidea, Late Jurassic)

The new genus Cieneguiticeras, assigned to the family Oppeliidae, is described on the basis of Andean lower-middle Tithonian ammonites from Arroyo Cieneguita, west-central part of the Neuquén-Mendoza Basin, Argentina. The macroconchs are closely homoeomorphic with Neochetoceras Spath and the microconchs have a ‘glochiceratid’-type morphology. The stratigraphic range of Cieneguiticeras nov. gen. includes the lower and middle Tithonian by means of a succession of two or three species which are interpreted as members of a phyletic lineage. Ammonites from the Tithonian of Cuba, Mexico and France are more or less confidently included in this new genus.     

Specialization and iterative evolution of some Western Tethyan Bathonian ammonites [Benatinites (B.) nov., B. (Lugariceras) nov. and Hemigarantia]

Late Bajocian to Early Bathonian ammonites, now attributed to Benatinites and Lugariceras, and Late Bathonian Hemigarantia, previously considered as cryptogenic taxa, share very similar sutural and ornamentation characters, suggesting their derivation from the stephanoceratid stock, most probably from the Cadomites-Polyplectites line. The palaeogeographical distribution of these taxa is limited to the North-Western African and European margins of Western Tethys. Palaeontologically, they represent the result of the iterative evolution rather than a poorly known lineage.     

Fauna and Predator-Prey Relationships of Ettling,an Actinopterygian Fish-Dominated Konservat-Lagerst?tte from the Late Jurassic of Southern Germany

The newly recognized Konservat-Lagerstätte of Ettling (Bavaria), field site of the Jura-Museum Eichstätt (JME), is unique among Late Jurassic plattenkalk basins (Solnhofen region) in its abundant, extremely well preserved fossil vertebrates, almost exclusively fishes. We report actinopterygians (ginglymodins, pycnodontiforms, halecomorphs, aspidorynchiforms, “pholidophoriforms,” teleosts); turtles; and non-vertebrates (echinoderms, arthropods, brachiopods, mollusks, jellyfish, sponges, biomats, plants) in a current faunal list. Ettling has yielded several new fish species (Bavarichthys incognitus; Orthogonikleithrus hoelli; Aspidorhynchus sanzenbacheri; Macrosemimimus fegerti). Upper and lower Ettling strata differ in faunal content, with the lower dominated by the small teleost Orthogonikleithrus hoelli (absent from the upper layers, where other prey fishes, Leptolepides sp. and Tharsis sp., occur instead). Pharyngeal and stomach contents of Ettling fishes provide direct evidence that Orthogonikleithrus hoelli was a primary food source during early Ettling times. Scarcity of ammonites and absence of vampyromorph coleoids at Ettling differ markedly from the situation at other nearby localities in the region (e.g., Eichstätt, Painten, Schamhaupten, the Mörnsheim beds), where they are more common. Although the exact biochronological age of Ettling remains uncertain (lack of suitable index fossils), many Ettling fishes occur in other plattenkalk basins of Germany (e.g., Kelheim) and France (Cerin) dated as Late Kimmeridgian to Early Tithonian (eigeltingense horizon), suggesting a comparable geologic age. The Ettling deposits represent an independent basin within the larger Upper Jurassic “Solnhofen Archipelago”, a shallow subtropical sea containing scattered islands, sponge-microbial and coral reefs, sandbars, and deeper basins on a vast carbonate platform along the northern margin of the Tethys Ocean.     

Les formations du jurassique supérieur du Bou Rheddou au Nord de Tiaret (Bordure sud-Tellienne,Algérie): âge et milieux de dépôt

In the Bou Rheddou mountain (Southern Tellian border), new biostratigraphic data based on Ammonites, allow precise and modify the age of the Arkell & Busson formations. The Oxfordian «Ammonitico rosso facies begin in the Transversarium zone and go into the Planula zone. This zone is characterized for the first time in this region. Lower Tithonian (Hybonotum zone) and Upper Tithonian (Microcanthum zone) are also recognized. Precisions on depositional environment and paleogeography are given. Facies and low sedimentation show a pelagic shoal (abundant planctonic organisms) slightly subsiding and lately recovered by the Jurassic transgression. During Oxfordian, episodic interruption of the «Ammonitico rosso deposits shows an unstable period with terrigenous deposits (intra-oxfordian tectonic movements). The facies of the Northern-Gondwanian carbonated platform begin earlier in the Bou Rheddou zone (Oxfordian-Kimmeridgian boundary) than in the Southern regions, where the same facies appears only in Upper Kimmeridgian.     

Myths and legends in the correlation between the Boreal and Tethyan Realms. Implications on the dating of the Early Toarcian mass extinctions and the Oceanic Anoxic Event

This study constitutes a revision of the biostratigraphy of Early Toarcian age ammonites coming from different successions in the NW Europe and Mediterranean areas, complemented by new, important data from the Migiana di M. Malbe section (Perugia, Italy). The research has demonstrated that the problems of correlation between some Zones of the Standard and Mediterranean biostratigraphic scales in this period are doubtful. On the negative side, procedural problems and defects have emerged that greatly detract from the validity of some boundaries which were, almost unanimously, held to be synchronous. Undervaluation of the problems brought to light in this study has had repercussions both on the construction of the eustatic curves and on the dating of the Oceanic Anoxic Event (OAE), and consequently on the evolutionary models for the various areas of the Tethys and of NW Europe. The various datings obtained by different writers have led to the belief that the anoxic conditions became established diachronically in the two areas. However, ammonite dating of the black shale-like facies, made for the first time in the Umbria–Marche Apennines, shows instead that, at least between this area and Germany, the diachronism was only partial. In both areas, the establishment of “anoxic” conditions took place in the Dactylioceras semicelatum Subzone. Problems linked to ammonite faunal provinciality and evolution, complicated by tectono-eustatic phenomena that produce hiatuses in NW Europe, are at the root of the lack of continuity in tracing the Pliensbachian–Toarcian boundary between the NW Europe area and the rest of the world.     

La limite Kimméridgien-Tithonien et l'âge des formations du Jurassique supérieur de la Dorsale tunisienne, comparaisons avec l'Algérie et la Sicile

The discovery of the Lowermost Tithonian Hybonotum-Lithographicum Zone allows for the first time to define the Kimmeridgian-Tithonian boundary in the pelagic and transitional facies (Béni Kleb Fm) of the Tunisian Dorsale and to divide within the formation the Kimmeridgian-lower Tithonian grey and/or pseudonodular mudstone and the massive Tithonian limestones. The Hybonotum-Lithographicum Zone was not identified in the reefal facies (Ressas Fm) and the Kimmeridgian and Tithonian are not divided. The Ressas Fm starts earlier, with the Upper Oxfordian, Bimammatum Zone. The Kimmeridgian-Tithonian of the Tunisian Dorsale is compared with the corresponding beds in Algeria and Sicily.     

Heteromorph ammonites from the Tata Limestone Formation (Aptian–Lower Albian), Hungary

An important new ammonite fauna was collected by Fülöp in 1953 and 1960 from basal lenses between a Tithonian hardground and the overlying Tata Limestone Formation containing many heteromorph ammonites. This assemblage of ammonites has been determined as being of Early Albian ( tardefurcata Zone) age. Among the heteromorphs are species of Tonohamites and Ptychoceras , which are familiar components of Late Aptian or Early Albian ammonite faunas. The genera Ephamulina , Hamites and Protanisoceras are also recorded, the earliest species of which had previously come from sediments of late Early Albian ( mammillatum Zone) age. While Hamites and Protanisoceras are common in Europe, Ephamulina had previously only been known from Madagascar. The discovery of Ephamulina , Hamites and Protanisoceras supports the view that these phylogenetically significant ammonites had radiated close to the Aptian/Albian boundary. Four new species of Hamites ( H. czaszari , H. fazekasensis , H. fueloepi and H. kalvariensis ) and one new species of Tonohamites ( T. boldii ) are described.     

L’assemblage à Cardioceras (Cardioceras) cordatum (J. Sowerby, 1812) et sa place au sein de la succession ammonitique de l’Oxfordien Inférieur (Jurassique Supérieur). Apport des données ardennaises (Province Subboréale)

Some temporary outcrops at Villers-le-Tourneur/Neuvizy (Ardennes, France), made possible the observation and biostratigraphical dating of Uppermost Callovian to Early Middle Oxfordian poorly known formations. Especially, the “Oolite Ferrugineuse de Villers-le-Tourneur–Neuvizy” is a quite thick marly unit, yielding some silicified fossils well known since the XIX^th century. With details, the Formation displays the succession of several faunal associations, characterizing the main subzones of the Cordatum Zone (Late Lower Oxfordian) and the Plicatilis Zone (Early Middle Oxfordian). Amongst many other species, Cardioceras cordatum (Sowerby, 1812) corresponds to a rare taxon or morphotype, yielded by the bottom part of the Formation. Then, the ultimate Lower Oxfordian faunal association is dominated by ammonites related to C. persecans. These Early Oxfordian are widely dominated by the family Cardioceratidae, commonly associated with Aspidoceratidae; such a structure is related to the “subboreal associations”, typically represented in Great Britain. Immediately after the Middle Oxfordian boundary, some “subtethysian” ammonites (mainly Perisphinctidae), occur in a larger number without being dominant, that emphasizing the northern location of the Ardennes margin. Then locally, two faunal associations succeed, which are characterized by C. cordatiforme (with Euaspidoceras perarmatum), and C. densiplicatum, respectively. Both are typical associations of the Vertebrale Subzone (Early Middle Oxfordian).     

Paleobiogeography of Mesozoic brachiopod faunas from Andean–Patagonian areas in a global context

During the Mesozoic, the Andean region has played a hinging role between high- and low-latitude faunas, which are, respectively, characterized by stocks that display long-term fidelity. This paper is aimed at providing an updated review of Late Triassic to Late Cretaceous South American articulated brachiopods in the light of previous knowledge at worldwide scale. Late Triassic brachiopods from the Argentine–Chilean Andes show unmistakable Maorian (or Notal) faunal elements alongside some more cosmopolitan genera, with certain influence of Eastern Pacific taxa. By Early Jurassic times, differentiation of Tethyan and Boreal Realms became progressively evident in Europe. In South America, Hettangian–Sinemurian brachiopod faunules from the Argentinian Andes are somewhat impoverished, with mostly cosmopolitan genera showing certain affinities to Maorian species, and with the addition of some endemics later. Increasingly, diverse Pliensbachian Andean brachiopods denote close relationships to Celto-Swabian taxa, then by Domerian times, a certain degree of endemism was developed, though somewhat delayed Tethyan influences, and persistent links with New Zealand are subordinately recognizable, too; most Toarcian assemblages reveal basically Celto-Swabian and Iberian affinities as well. East-west austral links across the Pacific may have been favored by migratory routes fringing the Gondwana margin, whereas faunal exchange with the western end of the Tethys appears to reflect an intermittent shallow-marine connection through the Hispanic Corridor. During the Middle Jurassic, distinction of Tethyan and Boreal Realms was maintained in the northern Hemisphere, and the differentiation of an Ethiopian or Southern Tethyan fauna became better characterized. Aalenian and Bajocian brachiopods of the Andes display generic affinities mainly with those from western Europe, with some minor endemic developments; brachiopods recorded from the Bathonian–Callovian of Argentina (and Chile) also occur along the northern Tethyan margin, yet with some genera extending into Indo-Ethiopian areas. During the Late Jurassic, Boreal faunas from high-latitudes became even more strongly differentiated from low-latitude, Tethyan ones. Oxfordian and Tithonian brachiopods from the Andes apparently belong to genera of cosmopolitan or northern Tethyan affiliation, yet there are few elements in common with other eastern Pacific areas, such as Mexico. Early Cretaceous brachiopods, in addition to Andean basins of Chile and western Argentina, are known also from Patagonia and Tierra del Fuego. They belong mostly to widely distributed, mainly Tethyan genera, with some quasi-cosmopolitan and circum-Pacific components (some shared with Antarctica become noticeable). Late Cretaceous brachiopods from northern Patagonia show significant affinities to Maastrichtian ones of northwest Europe and central Asia, which calls for further assessing the potential role that may have played the trans-Saharan passageway in such dispersal. Broad aspects of Mesozoic brachiopod paleobiogeography are fairly well understood, yet details of ranking and naming of certain units are still in need of more agreement.     

Corrélation des successions de l'Albien par les ammonites entre la Province Nord-Pacifique et les Provinces européenne et arctique du Domaine boréal : zonation, eustatisme et paléobiogéographie

The vertical distribution of Albian ammonites of the North Pacific Province is described on the basis of several sections located in Northern California. Nine Albian ammonite assemblages are identified, compared to the 4 previously described by Murphy in 1956. Owing to several gaps of observation possibly more assemblages could exist. In the North California Albian history, the first results show a succession of confinement periods - with numerous endemic faunas - followed by periods of open communications with other faunal provinces. As an example, the base of the Middle Albian is marked by exotic ammonites coming from the Tethyan realm (Oxytropidoceras, Lyelliceras) and from the Arctic Province of the Boreal realm (Gastroplites, Pseudopulchellia). These ammonites - except Oxytropidoceras - were not known in that area and are described relatively to their palaeobiogeographical interest. Although rare these migrant faunas give valuable elements to correlate these various provinces. Planktonic foraminifera confirm the existence of open sea communications during the uppermost Albian.With such faunal links, a comparison is proposed between the Albian ammonite zonation of Northern California and the standard and phyletic ones of Europe. This attempt suggests that the major connections between the three faunal provinces are established at second order peak transgressions in the Early and Middle Albian, and during the sea-level high of the Late Albian transgressive period. So, it seems that the vertical distribution of Albian non-endemic ammonites of North California and Europe is largely controlled by global eustatic events. Two palaeobiogeographic maps for Early and Middle Albian and one map for the late Late Albian show the migration outer of these exotic ammonites.     

ökologie und Taxonomie koralleninkrustierender Bryozoen des norddeutschen Malm

In the Late Oxfordian Korallenoolith of northern Germany, eight bryozoan taxa encrusting corals have been found, six of which had not been previously recorded in the area. In most cases, they can only be described using open nomenclature since the gonozooids are not known and the type material of existing species is too poorly preserved. “Stationary” bereniciform bryozoans were relatively good competitors adapted to a predictable environment. For this reason they thrived in the calm-water facies. However, the environment was disturbed frequently as proved by the joint occurrence with Stomatoporidae. These “mobile” taxa could grow fast on strongly three-dimensional surfaces, thus being able to survive even in highly agitated facies by escaping into cryptic habitats. The distribution of individual taxa is thus governed by the type and frequency of perturbations of their habitats. Bryozoans had a binding function in the fauna related to corals. Because of their low number and poor coverage, they mostly had little importance, however. This is due to the high water energy or high rate of sedimentation, which characterized the environments of the sampled localities. Thus, ideal habitats were not available. Nevertheless, the characteristic bryozoan associations of the European Jurassic became established together with typical associated faunal elements.     

Paleocene-Early Eocene ostracodes from the Southern Galala Plateau (Eastern Desert, Egypt): Taxonomy, impact of paleobathymetric changes

Ostracode faunas obtained from nine sections spanning the Paleocene-Early Eocene interval from a platform-basin transect in the Southern Galala Plateau area (Eastern Desert, Egypt) have been investigated. The study focuses on taxonomy and biostratigraphy of the ostracode assemblages across the P/E boundary, with supporting comments on paleoecology and paleobiogeography. The studied nine sections yielded 60 taxa belonging to 39 genera. Five species are new. The P/E transition is characterized by the appearance of new taxa rather than extinctions. During the Early and early Late Paleocene, the ostracode assemblages throughout the study area are largely similar, being dominated by middle-outer neritic taxa. In the late Late Paleocene and Early Eocene, changes in the paleobathymetry from deeper marine environments in the distal area in the south to shallower marine environments in the proximal area in the north become pronounced. Many of the recorded taxa have a wide geographic distribution throughout the Middle East and North Africa. Similarities with basins of West Africa are also found, reflecting faunal exchanges between this area and southern Tethys during the Paleocene and Early Eocene.     

Zonation des brachiopodes du Jurassique moyen sur la marge sud de la Téthys occidentale (Maroc, Algérie occidentale): Comparaison avec la marge nord-téthysienne française

A new and yet unpublished palaeontological revision of very important collections accomplished these last thirty years in many localities of Morocco and Western Algeria joined to the already published data, allow us to propose a biostratigraphical succession of the Middle Jurassic Brachiopods suitable to the Southern Margin of the Western Tethys. This Brachiopod scale is correlated with the standard chronostratigraphy based on ammonites. It involves eight zones and six sub-zones separated by five interval zones where Brachiopods are missing. Moreover, brachiopods have not been discovered in Early Aalenian and Late Callovian. Afterwards, the two brachiopod zonations established on the northern and southern margins of the Western Tethys are compared. On a paleontological plane, a new definition of the species Burmirhynchiaathiensis warrants to precise its vertical distribution (Parkinsoni and Zigzag zones) and to give a better distinction with Burmirhynchiatermierae (Humphriesianum and Niortense zones).     

Recovery of carbonate platform production in the Lombardy Basin during the Anisian: paleoecological significance and constrain on paleogeographic evolution

In the Central Lombardy Basin (Southern Alps) Anisian carbonate platform marginal facies yielding the first documented occurrence of coral colonies in this area of the Western Tethys has been recognized. These marginal facies identify the east-west transition between two sectors with a different Anisian evolution. West of the recognized marginal facies the Anisian succession is characterised by subtidal bioturbated limestones passing upward to peritidal dolostones, whereas toward the east a thicker succession of subtidal facies persist until the end of the Anisian. The margin belt develops at the passage between a more subsiding eastern portion and a less subsiding one toward the west. The different facies and thickness of the Anisian succession east and west of the marginal facies is indicative of syndepositional tectonics. The transition from subtidal to peritidal facies in the western sector is ascribed to a sea-level fall that favoured the onsetting of peritidal facies on the less subsiding block and of marginal facies on its border. The occurrence of a N-S trending syndepositional Anisian fault system could also explain the scarce progradational evolution of the margin facies, prevented both by the paleobathymetric setting and by the scarce productivity of the Anisian marginal communities. The presence, in the Anisian marginal facies, of crinoids and corals (together with the occurrence of one of the oldest specimen of coralline red algae) outlines the return to normal marine conditions and documents the recovery of the carbonate platform marginal faunal association after the Permo-Triassic crisis in the Western Southern Alps.     

New ammonoid taxa from the Lower Cretaceous Giumal Formation of the Tethyan Himalaya (Northern India)

Knowledge of the Early Cretaceous ammonoids of the NW‐Himalayas was poor until recent discoveries. Intense sampling from the Giumal Formation exposed near the village of Chikkim (Spiti Valley, Himachal Pradesh, India) led to the recognition of a new Early Cretaceous ammonoid fauna. The succession consists of arenitic sandstone interbedded with shale that was deposited by turbidity currents on an unstable shelf in the Early Cretaceous. Ammonoids have been obtained only from sandstone beds in the lower one‐third and close to the top of the c. 350‐m‐thick section. Eight new ammonoid taxa (1 genus and 7 species) are described: Sinzovia franki sp. nov. (rare), Giumaliceras giumaliense gen. et sp. nov. (abundant), Giumaliceras bhargavai gen. et sp. nov. (rare), Neocomites (Eristavites) platycostatiformis sp. nov. (rare), Cleoniceras oberhauseri sp. nov. (abundant), Australiceras himalayense sp. nov. (rare) and Deshayesites fuchsi sp. nov. (rare). Sinzovia and Deshayesites are reported for the first time from the Tethyan Himalaya. According to the biostratigraphic relevance of some ammonoid taxa described here, the age of the Giumal Formation can be constrained from Berriasian (Giumaliceras assemblage) to Aptian (Cleoniceras assemblage). The discovery of the new fauna substantiates the significance of the Giumal Formation around Chikkim and facilitates comparison with faunal assemblages from other regions in the Tethys Ocean and beyond.     

Biostratinomy and palaeoecology of the cassian formation (Triassic) of the Southern Alps

The sediments forming the Cassian Formation (Middle—Upper Triassic) of the Central Dolomites represent the following environments: back-reef areas, shallow marginal basins, slope, and central basin. In each of these major environments faunal assemblages were found whose composition, mode of preservation and occurrence proved to be characteristics. In the back-reef areas, algal/foraminifera- and calcareous sponge/coral-patch reefs with a highly diverse fauna of frame-builders and reef-dwellers, in some localities excellently preserved, form the most conspicuous feature. In the shallow marginal basins autochthonous algal meadow/soft-bottom associations dominated by gastropods and deposit-feeding bivalves prevail. Slope deposits do not contain any autochthonous associations but either remains of pelagic faunas or transported faunal elements of shallow-water origin in the form of Cipit boulders (subaerially cemented parts from the outer edge of the carbonate platforms), worn Pachycardia rugosa-dominated, or echinoderm debris-dominated assemblages. Sediments of the central basin lack benthic faunas but contains pelagic assemblages of low diversity dominated by Daonella, Posidonia, and some ammonites.     

Ecological traits of benthic assemblages in shallow Antarctic waters: does ice scour disturbance select for small, mobile, secondary consumers with high dispersal potential?

Benthic communities in nearshore habitats around Antarctica are strongly influenced by ice disturbance. It has been suggested that where ice scour disturbance is severe, the relative importance of certain ecological groups is elevated. I examined the relative contributions of mobility, size, feeding strategy and development mode groups to total faunal abundance and species richness in relation to ice disturbance at Adelaide Island, West Antarctic Peninsula. The contributions of ecological groups were assessed along a depth/disturbance gradient from 5 to 25 m depth at two sites. At one site, the relative abundance of the low mobility group was significantly greater at low disturbance levels, whilst the relative abundance of the high dispersal group (taxa with pelagic larvae) was elevated at high disturbance levels. At the other site, the relative abundance of secondary consumers was greater at high disturbance levels. Even over small spatial scales, certain ecological traits seem advantageous to a fauna shaped by intense, catastrophic ice scour.     

The ecology of two intermittent streams in Victoria, Australia

1. We compared aquatic macroinvertebrate assemblage composition within and between habitats (pools and riffles) at four sites on two intermittent streams in Victoria, Australia during a drought year followed by a wetter year to see how different spatial and temporal scales influenced patterns of community structure detected by multivariate techniques of ordination and classification. We also examined the fit between faunal groups and ‘flow phases’ characterized by multivariate analyses of physicochemical variables in an earlier paper. 2. Pools contained more taxa and individuals than riffles. At the more temporary site, there was considerable overlap between the faunal composition of pools and riffles, whereas habitat-specific assemblages consistently occurred at the more permanent sites. Most taxa were either tolerant, permanent stream forms able to persist in streams that dry briefly, or facultative species that occur in lotic or lentic habitats. Few species appeared specifically adapted to temporary waters. 3. Within habitats, there were some matches between faunal groups and flow phases, especially with the onset of the ‘diminishing flow’ phase, characterized by rising water temperature and conductivity, and declining pH and dissolved oxygen. However, disjunctions among faunal groups were less marked than those between flow phases, and were absent at an intermediate scale when habitats were pooled within sites. At the broadest scale of analysis (within habitats between sites and years), historical events (e.g. whether pools upstream dried completely during the previous summer) apparently influenced community composition as much as site-specific abiotic differences.     

Biostratigraphie des brachiopodes et âge carixien (Pliensbachien inférieur) des calcaires à grands bivalves en Algérie occidentale

Recent researches on the Lower Jurassic of Western Algeria allow to establish a lithostratigraphic standard correlating the different members and formations developed in the Ouarsenis and Tlemcen Mountains, the Oran High Plains, the Nador and Ksour Mountains. The position of the large bivalve limestones (= Lithiotis limestones) is well established in the different lithologic successions. This facies is widespread in Western Algeria where it is interbedded with brachiopod marker beds, indicating short periods of maximum flooding. The large number of collected brachiopods are distributed into four “faunas” (assemblages) ranging from the Late Sinemurian (= Lotharingian) to the Early Pliensbachian (= Carixian). These faunas have been dated by the age of the species that they have in common with the NW european and western tethyan provinces. These chronological data are confirmed by rare ammonites. All these results evidence the age of the large bivalve facies in Western Algeria. They are contained in the Middle to Late Carixian (Demonense and Dilectum Zones). This datation is in conformity with that known from the Eastern High-Atlas (Bou Dahar). Consequently, the large bivalves cannot be considered as “markers for the unique Domerian” as it has been too often asserted. The palaeontological part of our study shows that the multicostate Zeilleriids (several Tauromenia species from the Late Sinemurian to the Early Carixian) are older than the multicostate Terebratulids (Hesperithyris species from the Middle to Late Carixian).