Quantitative study of a hippuritid rudist lithosome in a Santonian carbonate platform in the southern Central Pyrenees

The Santonian carbonate platform deposits of the Sant Corneli anticline in the southern Central Pyrenees contain distinctive lenticular to tabular lithosomes formed by congregations of slender hippuritid rudists. Here we make a quantitative study of one of the lithosomes in the Sant Pere de Vilanoveta Member, in the northern side of Sant Corneli. It is exposed over some 4 km, along a WNW–ESE section, and shows a remarkably persistent thickness up to a maximum of 5.15 m, though for the most part it is less than 3 m thick. In the lithosome, hippuritid shells are mostly preserved inclined about 30°–60° from the perpendicular with respect to bedding. The majority of inclined shells lean towards the southwestern to southeastern quadrants, the inferred principal downstream direction. Hippuritids are loosely clustered and supported in a fine bioclastic matrix. Percentage cover of hippuritids ranges from 19.8% at the base to 31.9% in the middle and top of the lithosome. The preliminary data on numerical densities (number of individuals per unit area) of hippuritids show some clustering around values of about 290–750 individuals per m². The inclined orientation of hippuritid shells seems original and the result of active growth by the animals. The high numerical density of hippuritids at the base of the lithosome may indicate that the hippuritid congregation grew rapidly. The congregation appears to have reached an optimal level of density by the middle of the lithosome and to have maintained it through time during the development of the rudist congregation. The lithosome lacks relief and has no evidence of any rigid framework.     

Dinoflagellate cyst biostratigraphy of the Coniacian–Santonian (Upper Cretaceous): New data from the English Chalk

Results are presented here for the first chalk-based, high-resolution quantitative study of organic-walled dinoflagellate cysts (dinocysts) from the entire Coniacian–Santonian Chalk successions in east Kent and on the Isle of Wight. The lithostratigraphy and dinocyst records (137 taxa) of seven sections are presented, and the stratigraphic ranges of taxa are constrained relative to stage and zonal boundaries, located using extensive macrofossil data. Results are integrated with a previous complementary study of the Isle of Wight Santonian to test and refine existing dinocyst bioevent schemes. Sixteen dinocyst events are proposed as a sequence of biostratigraphic datum levels for the lower Coniacian to uppermost Santonian which, based on average sedimentation rates, represent an average temporal resolution of around 360 kyr. The event stratigraphy forms a basis for the first high-resolution correlation study of quantitative dinocyst data from the Upper Cretaceous of NW Europe. A new genus Culversphaera Prince, Jarvis, Pearce et Tocher gen. nov. is proposed with the new combination Culversphaera velata Prince, Jarvis, Pearce et Tocher gen. et comb. nov. Five new species: Ellipsodinium membraniferum Prince, Jarvis, Pearce et Tocher sp. nov., Senoniasphaera macroreticulata Prince, Jarvis, Pearce et Tocher sp. nov., Senoniasphaera whitenessii Prince, Jarvis, Pearce et Tocher sp. nov., Xenascus spinatus Prince, Jarvis, Pearce et Tocher sp. nov. and X. yunii sp. nov., and the new subspecies S. protrusa congrensa Prince, Jarvis, Pearce et Tocher subsp. nov. are described.     

Evolutionary trend of Zoophycos morphotypes from the Upper Cretaceous–Lower Miocene in the type pelagic sections of Gubbio,Italy

About 200 Zoophycos specimens, including 90 specimens studied in detail, have been analysed in the continuous Upper Cretaceous–Lower Miocene pelagic sedimentary type sections of the Gubbio area (the Contessa Highway, Contessa Quarry and Bottaccione sections, Northern Apennines). The sediments are reddish to grey limestones and marls of the Scaglia Group and marls with volcaniclastic deposits of the Bisciaro Formation. The aim was to examine the evolutionary trend of what is probably the most debated trace fossil of all time, from the Upper Cretaceous to Lower Miocene. Despite having been found in beds ranging from the Cambrian to the present, no consensus has been reached regarding mode of construction, tracemaker or ethological explanation for Zoophycos. Four Zoophycos morphotypes are recognized at Gubbio showing variations of major and minor lamellae, apex, lobes and whorls: the Cretaceous–Eocene cone‐shaped type 1, the Upper Eocene–Middle Oligocene helicoidal type 2, the Oligocene lobate type 3 and the Upper Oligocene–Lower Miocene flat type 4. The very high ichnodensity in some beds (hundreds of specimens in discrete levels of the Bisciaro Formation, now destroyed by quarrying) seems to find explanation in abnormal concentrations of phytodetritus and organic matter on the seafloor in some periods. This very high abundance in discrete levels reflects a change in sedimentation and seafloor conditions at pre‐flysch deposition. Due to such high ichnodensity, many adjacent specimens display deformed outer margins. Taphonomic analysis shows a variation of whorls, laminae and U‐shaped lobes, reflecting ontogenetic development of the tracemaker(s) (?sipunculid worms).     

Integration of subsidence and sequence stratigraphic analyses in the Cretaceous carbonate platforms of the Prebetic (Jumilla–Yecla Region), Spain

An integrated analysis of subsidence and sequence stratigraphy of the Cretaceous successions of the Jumilla–Yecla Region (Betics, SE Spain) is supported by abundant stratigraphical, sedimentological and palaeontological data, with the aim to document and explain the accommodation changes that controlled the evolution and architecture of the carbonate platforms generated during that time on the southern continental margin of Iberia. The Cretaceous shallow marine carbonates and clastics that extensively crop out in the Jumilla–Yecla Region are divided into 11 sequence sets (major stratigraphic units bounded by tectonically induced unconformities), which can be subdivided into several third order depositional sequences and their constituent system tracts. All these genetic units build up a regional chronostratigraphic framework, which is herein used to support subsidence calculations. From the results of the subsidence analysis, seven intervals with characteristic tectonosedimentary patterns were distinguished for Cretaceous time. From these intervals, the first three (respectively early Tithonian–early late Berriasian, late Berriasian–late Hauterivian, and latest Hauterivian to earliest late Albian) were controlled by extensional tectonics, strong enough to mask, during most part of the time, the long-term thermal subsidence inherent to the continental margin. This tectonism was related to the Iberia–Africa divergence and the opening of the North Atlantic. Later, the fourth interval (late Albian–mid Cenomanian) and the sixth interval (late Coniacian to late Santonian) were characterised regionally by, overall, homogeneous subsidence patterns controlled by thermal subsidence, sediment loading and a relative tectonic quiescence. Finally, the fifth and the seventh intervals (respectively latest Cenomanian–early Coniacian and Campanian–Maastrichtian) were characterised by strong tectonic movements and complex subsidence patterns which were related to changes in intraplate stresses related to the onset of the convergence between Africa and Iberia and with the evolution of the Bay of Biscay.     

Hints of economic change during the late Roman Empire period in central Italy: a study of charred plant remains from “La Fontanaccia”, near Rome

The archaeobotanical study of the charred macro-remains recovered from the burnt settlement of La Fontanaccia, Allumiere, 50 km northwest of Rome, a small hut from the time of the end of the late Roman Empire, provided results on the use of food of its inhabitants, their living conditions, and the natural environment. The fire which destroyed the small settlement was archaeologically dated to the middle of the 5th century a.d., few years before the end of the Roman Empire. This was a period in which the state structure, undermined by the barbarian invasions which provoked famine and destruction, was in deep economic and political crisis, and the population in Rome and in the countryside lived in precarious conditions. No archaeo-botanical data have been available until now for this period in the region of Rome. The presence of grass peas, acorns, two-rowed barley caryopses, and small horse bean seeds demonstrate the general state of regression in the late Roman Empire, when misery and famine were widespread. The finds of charcoal from chestnut, deciduous oak, maple and elm suggest the presence of thermophilous deciduous woods and environmental conditions similar to today’s. It deserves mention that this is the first site in which macro-remains (charcoal) of Castanea have been found in central Italy.     

Unveiling biases in soft‐tissue phosphatization: extensive preservation of musculature in the Cretaceous (Cenomanian) polychaete Rollinschaeta myoplena (Annelida: Amphinomidae)

The process of soft‐tissue phosphatization (the replication of labile tissues by calcium phosphate) is responsible for many instances of high‐resolution soft tissue preservation, often revealing anatomical insights into the animals that so preserved. However, while much work has gone into exploring key issues such as biases and micro‐controls, phosphatization remains poorly understood as a taphonomic process. Here, using camera lucida, plain‐light microscopy and SEM imagery, we address this issue by describing the taphonomy and fidelity of the musculature of Rollinschaeta myoplena Parry et al., a phosphatized annelid from the Cretaceous Konservat‐Lagerstätten of Hakel and Hjoula, Lebanon, with an unprecedented quantity of three‐dimensional soft‐tissue preservation. Analysis highlights two strong, previously recognized biases affecting the process of phosphatization: (1) a taxonomic bias restricted to R. myoplena that triggers unusually extensive phosphatization; and (2) a tissue bias whereby longitudinal and parapodial musculature show markedly higher fidelity in comparison to the musculature of the intestine and body wall circular muscles. Potential explanations for these biases include internal phosphate‐enrichment by relative muscle density, the relative rate of decay and the physiology of musculature. Incongruence between experimental decay series for polychaetes and the prevalence of labile tissue preservation over recalcitrant tissues in R. myoplena exposes the limits of decay experiments for understanding exceptional preservation.     

Fossil isopods associated with a fish skeleton from the Lower Cretaceous of Queensland,Australia – direct evidence of a scavenging lifestyle in Mesozoic Cymothoida

Abstract: A dense assemblage of fossil isopod crustaceans (Brunnaega tomhurleyi Wilson, sp. nov.) from the Lower Cretaceous (Albian) Toolebuc Formation of Queensland, Australia, has been found within the carcass of a large actinopterygian fish, Pachyrhizodus marathonensis (Etheridge). Preservation of fine anatomical details supports referral to the genus Brunnaega Polz, which is herein reassigned to the family Cirolanidae. Furthermore, placement of this taxon within the cirolanid subfamily Conilerinae Kensley and Schotte is significant because the group includes modern species that are well known as voracious scavengers. This isopod–fish association represents the oldest unequivocal evidence of scavenging by Mesozoic cymothoidean isopods on a large vertebrate carcass.     

Berriasian–Aptian black shales of the Maiolica formation (Lombardian Basin, Southern Alps, Northern Italy): local to global events

The Lower Cretaceous Maiolica Formation represents the classic pelagic succession of the Apulian margin of the Tethys Ocean, in the Southern Alps. It consists of white calcilutites with minor marly layers and black shales. A multidisciplinary study including lithostratigraphy, nannofossil assemblage composition and organic geochemistry was performed on two composite sections in order to characterise the marl–shale layers that record production and storage of organic matter (OM) and terrigenous input in the Berriasian–Aptian interval. Such layers are associated with turbidite deposition and bottom current activity in the Late Berriasian–earliest Valanginian, Late Valanginian and Early Aptian. The uppermost Hauterivian–Barremian black shales alternate with pelagic calcilutites, forming an interval barren of redeposited layers. The quantity of organic carbon increases from the Berriasian to the Barremian; the background composition of the kerogen is continental-dominated, with varying proportions of marine-derived OM. Preservation of OM did not necessarily occur under anoxic conditions; on the contrary, storage of OM probably resulted from enhanced terrestrial input of nutrients, siliciclastics, woody and herbaceous fragments, inducing mesotrophic conditions and increased primary productivity. Higher fertility of surface waters during the Late Valanginian and Early Aptian is reflected by distinctive decreases in abundance of oligotrophic nannoconids and increase in abundance of mesotrophic Diazomatholithus in the Valanginian. During the Barremian, the rhythmic establishment of eutrophic conditions, documented by the highest amounts of marine OM, determined high-frequency fluctuations in nannoconid abundance. The Early Aptian nannoconid crisis is interpreted as the result of a major climate change and enhanced primary productivity. Variations of calcareous nannofloras, as well as changes of lithology and OM, which we describe in the Lower Cretaceous Maiolica Formation of the Lombardian Basin, can also be recognised in coeval units from other sites of the Apulian side of the Tethys. Similar episodes of siliciclastic and terrestrial OM accumulation and major changes in calcareous nannofossils are also recorded in the Upper Valanginian and Lower Aptian pelagic sediments of the Tethys, Atlantic and, partly, Pacific oceans. Such nannofossil variations are coeval with positive excursions of the δ¹³C curve and suggest perturbations of the bio-geochemical cycles at a global scale. Additional minor changes in siliciclastic and terrestrial OM accumulation as well as in nannofloras are probably the result of local events, strictly related to the physiography and evolution of the Tethyan margin.     

Biostratigraphical correlation of late carboniferous (Kasimovian) sections in the Carnic Alps (Austria/Italy): Integrated paleontological data, facies, and discussion

Summary The fusulinacean faunal content of the Bombaso Fm. and lower part of the Auernig Group (Carnic Alps, Austria/Italy) is reviewed and completed by data on conodonts and algae. Four different faunal associations can be distinguished within this stratigraphic interval. The beginning of the postvariscan sedimentation in the investigated sections is diachronous, shifting in age from early Kasimovian (Krevyakinian) at Zollner Lake and Mt. Auernig, early to middle Kasimovian at Cima Val di Puartis to late Kasimovian (Dorogomilovian) at Mt. Ro?kofel. The sections analyzed consist of shallow-marine sediments, which differ in microfacies of limestones and partly in biotic assemblages. They are geographically isolated and could not be traced laterally for lithologic correlation in the field. The biostratigraphic correlation with the faunas of the stratotype sections in the Moscow Basin is hindered by the searceness of fusulinaceans in the critical levels, especially in the lowermost Kasimovian, and differences in the species composition. A biostratigraphic correlation of the Bombaso Fm. and basal part of the Auernig Group with the Peski Fm. (Myachkovian) of the Moscow Basin, as suggested byDavydov & Krainer (1999), is not confirmed by our results. Due to our taxonomic reinterpretation of the oldest fauna (Protriticites aff.permirus with distinct mural pores and largeBeedeina (Pseudotriticites) asiaticus) a lowermost Kasimovian (Lower Krevyakinian) age is more probable. This correlation is supported by the co-occurring conodont fauna, which is suggested to belong to the zone of “Streptognathodus subexcelsus”. This biozone reaches from the topmost Peski Fm. to the Suvorovo Fm. (Lower Krevyakinian) in the Moscow Basin, and may be correlated with the uppermost Desmoinesian of the Midcontinent North America. Fusulinaceans and conodonts of the overlying strata at Zollner Lake and from the sections at Cima Val di Puartis and Mt. Auernig most probably correspond to the upper Krevyakinian/lowermost Khamovnikian of the Russian platform (Lower Missourian of the Midcontinent North America). The algal associations (Dvinella, Beresella, Herakella) from these lowermost strata are unique for the Carnic Alps. Their stratigraphic range points to Moscovian-Kasimovian as well, and fits with the fusulinacean and conodont data. Sediments of the N?lbling Group (=“untere kalkreiche Schichtgruppe”) have their correlative levels in the upper Khamovnikian, but reach higher into the Dorogomilovian. More reliable correlations are possible with the fusulinacean faunas of the Cantabrian Mts. and Central Asia, based on the coincidence of several species. A revised biostratigraphic correlation with the different remote basins of the Paleotethyan realm and the Russian Platform is given, based on own data and recent results by the members of the SCCS Working group to define a GSSP close to the Moscovian/Kasimovian boundary. The sequence-stratigraphic scheme, the systematics, and the biostratigraphic correlation ofDavydov & Krainer (1999) are discussed.     

Analysis of Late Jurassic to Early Cretaceous algal debris-facies of the Plassen carbonate platform in the Northern Calcareous Alps (Germany,Austria) and in the Kurbnesh area of the Mirdita zone (Albania): a tool to reconstruct tectonics and palaeogeography of eroded platforms

A characteristic microfacies of the Late Jurassic to Early Cretaceous allodapic Barmstein Limestone of the Northern Calcareous Alps are clasts of wackestones with numerous fragments of calcareous algae (“algal debris-facies”). According to dasycladale palaeocoenoses, several subtypes comprising different associations can be distinguished. One association is characterized by the debris of an unknown large dasycladalean alga reported as dasycladalean alga indet. sp. 1 from different localities in the Northern Calcareous Alps, typically forming a monospecific assemblage. Another microfacies type contains star-like calcitic bodies tentatively referred to the morphospecies Coptocampylodon pantici Ljubović-Obradović and Radoičić, originally described as being from the Turonian of NW-Serbia. Other Coptocampylodon-like bodies represent the calcified tufts of the laterals of Selliporella neocomiensis (Radoičić). The occurrence of Coptocampylodon pantici-like microfossils in the Late Tithonian to Early Berriasian, shows that obviously different species of dasycladaleans display identical to similar shaped tufts of laterals in transverse sections when becoming fragmented. Coptocampylodon pantici Ljubović-Obradović and Radoičić was observed only from different occurrences of Barmstein Limestone, but not from the autochthonous platform carbonates of the Plassen carbonate platform. The Coptocampylodon algal debris-facies is also reported from the Late Jurassic of Albania, Mirdita zone. Occurrences of different types of algal debris-facies in components of mass-flow deposits can be used as a tool to reconstruct eroded carbonate platforms and tectonics, as demonstrated in the Northern Calcareous Alps and the Albanides. Finally, the general occurrences of algal debris-facies in both settings—intra-Tethyan mostly isolated platforms (Alps, Albanides) vs. extended epeiric platforms (Middle East)—are compared and discussed.     

Cenomanian–Turonian carbonate and organic-carbon isotope records, biostratigraphy and provenance of a key section in NE Sicily, Italy: Palaeoceanographic and palaeogeographic implications

In eastern Sicily, a series of highly organic-rich black shales occur as exotic blocks (~ 100 m across) floating in tectonized sediments (Argille Varicolori Unit containing olistoliths of Cretaceous–Palaeogene age). A 19-metre section, through one of these blocks near the town of Novara di Sicilia, includes cyclically bedded black shales, marlstones and claystones, which have been dated using planktonic foraminiferal and nannofossil biostratigraphy. On this basis, the section is assigned to the latest Cenomanian and clearly represents a manifestation of the Oceanic Anoxic Event characteristic of that interval. Total organic-carbon values range up to 23% and the relatively high hydrogen indices record the presence of marine organic matter of low thermal maturity. High-resolution carbonate and organic-carbon isotope curves are comparable with those recorded elsewhere in indicating a significant positive excursion and confirm that, in the Novara di Sicilia section, the black shales are latest Cenomanian in age. By comparison with Cenomanian–Turonian black shales exposed elsewhere in Italy (Calabianca section, western Sicily; Livello Bonarelli, Bottaccione Gorge, Gubbio, Marche–Umbria), the section of Novara di Sicilia is different in being more stratigraphically expanded. However, this section from eastern Sicily does resemble extremely closely coeval sediments cropping out in Tunisia and Morocco. This association is taken as evidence that the Argille Varicolori Unit includes elements that were initially deposited on the north African shelf during Cretaceous time.     

Phylogeography of the pool frog Rana (Pelophylax) lessonae in the Italian peninsula and Sicily: multiple refugia,glacial expansions and nuclear–mitochondrial discordance

Aim To infer the evolutionary history of Rana (Pelophylax) lessonae Camerano within its inferred Quaternary refugial range, and to shed light on the processes that have contributed to shaping the patterns of diversity within the southern European peninsulas. Location The Italian peninsula south of the Alps and Sicily. Methods Sequence analysis of a mitochondrial cytochrome b gene fragment in 149 individuals sampled from 25 localities. Results Three mitochondrial DNA (mtDNA) phylogroups were identified, distributed in northern Italy, the whole Italian peninsula south of the northern Apennines, and Sicily. Syntopy between the northern and peninsular lineages was observed close to the northern Apennines. The northern lineage was the most differentiated, showing a net sequence divergence of 4.8 ± 0.8% with respect to the two others, whereas the net divergence between peninsular and Sicilian lineages was 2.6 ± 0.6%. Analysis of molecular variance (amova ) revealed that 93% of the overall variation occurred between these three groups. Historical demographic statistics support a recent expansion for both the northern and peninsular groups, but not for the Sicilian group. In both northern and peninsular Italy, such an expansion was likely to have occurred during the last glaciation. Main conclusions Our results suggest that a number of microevolutionary processes were involved in shaping the present genetic structure of R. lessonae in Italy. These encompass allopatric differentiations in three distinct Pleistocene refugia, recent population expansions and secondary contacts. Our results, together with some previous work, support (1) the existence of a suture zone in the northern Apennines, and (2) the possibility of population expansions during the last glacial phase, when a vast widening of the lowland floodplain habitats followed sea‐level fall, particularly in northern Italy. When compared with previous analyses of allozyme data, it appears that the peninsular mtDNA lineage has recently replaced the Sicilian one in southern Calabria, and we suggest that this event occurred due to selective introgression. The implications of such an occurrence for the study of factors underlying the patterns of diversity within this southern European biodiversity hotspot are discussed. Taxonomic implications of the results are also evaluated.     

Avian fossil assemblages at the onset of the LGM in the eastern Alps: A palaecological contribution from the Rio Secco Cave (Italy)

The avian fossil assemblages from the late Pleistocene deposits of the Rio Secco Cave (north-eastern Italy) is presented herein. We studied the layers that date back to the end of MIS3 and the beginning of MIS2, which also contain evidence of Gravettian frequentation dated to 33.5–30 ka cal BP. The systematic analysis revealed the presence of 18 species and other supraspecific taxa that supported palaeoenvironmental reconstructions. Taxa indicate that, at the onset of LGM, site surroundings were characterised by conifer or mixed forests, open grasslands, slow-flowing water bodies and mountain meadows with rocky outcrops, as indicated by Lagopus muta. Today, this environment is found above the tree line (beyond 1500–2000 m) and cannot be detected near the site, located at 580 m asl. Noteworthy, is also the finding of the second Italian late Pleistocene fossil record of Picus canus.     

Biostratigraphic subdivision and correlation of Uppermost Carboniferous/Lower Permian sediments in the Southern Alps: Fusulinoidean and condont faunas from the Carnic Alps (Austria/Italy), Karavanke Mountains (Slovenia), and Southern Urals (Russia)

Summary In order to establish a refined biostratigraphic subdivision and correlation of the Uppermost Carboniferous/Lower Permian deposits of the Southern Alps (Carnic Alps, Karavanke Mountains; Austria/Italy/Slovenia), two major microfossil groups (fusulinoideans, conodonts) were investigated within the same sample. The fusulinoidean species diversity (71 species, including five new species and three new subspecies) and generic composition were reviewed and complemented. Additionally, the data on fusulinoidean assemblages were supplemented by co-occurring conodont faunas (seven species). Accompanying studies on material from the type sections of the Southern Urals (Russia) were made to improve the biostratigraphic correlation with the Russian standard zonation and to discuss paleobiogeographical aspects of the faunal associations. An integrated microfacies analysis of the sampled material in the Southern Alps serves to evaluate the relationships between certain genera and specific microfacies types. The fusulinoidean fauna of the Lower “Pseudoschwagerina” Limestone is of late Gzhelian age. The Carboniferous/Permian boundary is close to the base of the Grenzland Formation, which covers the entire Asselian and a part of the Sakmarian. The Upper “Pseudoschwagerina” Limestone and Trogkofel Limestone are Lake Sakmarian to Artinskian. The studies sequences in the Karavanke Mountains. formerly known as “carbonate and clastic Trogkofel beds”, correlate to the Lower “Pseudoschwagerina” Limestone, respectively with parts of the Grenzland Formation. Due to the lithologic differences, new formation names (Dolzanova Soteska Fm., Born Fm.) were introduced for the so-called “Trogkofel” Limestone along the Dolzanova Soteska. Whereas late Gzhelian/Asselian fusulinoidean faunas of the Southern Alps correspond to the Southern Uralian faunas to a large extent, Sakmarian and Artinskian faunas reveal an increasing divergence in species and genus composition. Climatic as well as geographic barriers may have prevennted the dispersal of Paleotethyan taxa into the Southern Urals. Biostratigraphic correlation of Sakmarian to Artinskian deposits is therefore possible only on the basis of the sparse conodont faunas.