The genus Laxifenestella (Bryozoa) from the Lower Carboniferous of the East European platform

Twelve species of the genus Fenestella from the Lower Carboniferous of the East European platform are placed in the genus Laxifenestella Morozova, 1974 based on the analysis of its species composition. These species and their stratigraphical range are described in more detail. Two species are shown to be synonymous. The stratigraphical distribution of these species over the horizons of the Viséan and Serpukhovian stages of the East European platform suggests a high degree of endemism of these bryozoans.     

Biostratigraphical dating of Cretaceous coral communities using large data sets

Habitats of hermatypic corals are shallow and turbulent marine environments that often lack biostratigraphic index fossils. For that reason many Cretaceous coral faunas are imprecisely dated or dated only on the basis of comparisons with other coral faunas. Using a large database on the taxonomy, stratigraphical and geographical distribution of corals in the Cretaceous, a method is proposed that will make it possible to specify the stratigraphical age of coral associations on the basis of their specific composition. In this process the stratigraphical range of the species (calculated before from well-dated faunas) is summarized and a probable age of the association proposed. The method does not only help to assess the biostratigraphical age of a fauna, but may also indicate whether a fauna represents an original composition or is a mixed association derived from reworked horizons or olistoliths. The method can be applied to any other group of organisms, provided that the essential data for a comparison are available.      

The stratigraphy of mass extinction

Patterns of last occurrences of fossil species are often used to infer the tempo and timing of mass extinction, even though last occurrences generally precede the time of extinction. Numerical simulations with constant extinction demonstrate that last occurrences are not randomly distributed, but tend to cluster at subaerial unconformities, surfaces of forced regression, flooding surfaces and intervals of stratigraphical condensation, all of which occur in predictable stratigraphical positions. This clustering arises not only from hiatuses and non‐deposition, but also from changes in water depth. Simulations with intervals of elevated extinction cause such clusters of last occurrences to be enhanced within and below the interval of extinction, suggesting that the timing and magnitude of extinctions in these instances could be misinterpreted. With the possible exception of the end‐Cretaceous, mass extinctions in the fossil record are characterized by clusters of last occurrences at these sequence stratigraphical horizons. Although these clusters of last occurrences may represent brief pulses of elevated extinction, they are equally likely to form by stratigraphical processes during a protracted period (more than several hundred thousand years) of elevated extinction rate. Geochemical proxies of extinction causes are also affected similarly, suggesting that many local expressions of mass extinction should be re‐evaluated for the timing of extinction and its relation to environmental change. We propose three tests for distinguishing pulses of extinction from clusters of last occurrences produced by stratigraphical processes.     

Revidierte Systematik der Ostracoden im Oberjura und der basalen Kreide Ostdeutschlands

The Upper Jurassic and basal Cretaceous ostracod faunas of Northeastern Germany, which have not been sufficiently investigated and documented yet, are revised. The fauna, documented by stratigraphical tables and SEM-pictures, consists of 116 species from 36 genera, two species of which are new:Galliaecytheridea wienholzae n. sp. andRasthalmocythere keuppi n. sp. The biostratigraphical ränge of the taxa extends from the Oxfordian to the early Berriasian. A palaeobiogeographical correlation with the ostracod faunas of Northwestern Germany reveals close relationships between both areas concerning the stratigraphical range and assemblage of the fauna.     

Organic evolution and natural stratigraphical classification

Krassilov, Valentin 1978 04 IS: Organic evolution and natural stratigraphical classifcation.
Typological stratigraphy persisted up to the early 1940's. when it gave way to gradualistic concepts. Because world-wide periodicity of evolutionary events and their functional relations to crustal disturbances were denied, it was decided to define geological time divisions by a set of time-planes marked by agreed reference points. Actually, evolution is discontinuous at the molecular, population, species and community levels. Evolution of the whole biosphere depends on periodicity of tectonic and climatic events which add to general environmental instability and alter adaptive strategies. The perception of geological time is derived from the succession of unique litho- and biosphere events which Serve as a base of natural stratigraphical classification. Correlation is based on the parallelism of cliseres and chronoclines. Their homotaxial members are recognized as coenozones and phenozones. Standard stratigraphical boundaries are materialized in local boundaries defined by historical events of high 'confidence level'. Nominotypes designated for nomenclatural procedures need not coincide with the boundary reference points; otherwise they would hamper further development of stratigraphical classification.     

Cricetodontini from the Calatayud–Daroca Basin (Spain): A taxonomical description and update of their stratigraphical distributions

The most updated stratigraphical distributions of the Cricetodontini from the Calatayud–Daroca Basin are presented. Cricetodon sansaniensis (local biozone F, MN6, middle Aragonian) and Cricetodon jotae (local biozone G1, G2 and G3, MN6-MN7/8, Middle–Upper Aragonian) from the middle Miocene are described and discussed. Generally, the genera of Cricetodontini were used to define large time intervals, whereas the species were neglected in the local biostratigraphical studies. The results presented herein show that, for the Calatayud–Daroca Basin, most of the stratigraphical distributions of the species of Cricetodontini are strongly linked with the local biozonation. That reveals that they could be used as good biostratigraphical indicators. Moreover, the unusually long local biozone G3 could be redefined and subdivided based on the distributions of the four species of Cricetodontini present in it. However, it is recommended to complete the study of the whole rodent fauna before proposing a new biozonation.     

British mammals of the Mesozoic Era

A brief account is given of the stratigraphical distribution of British Mesozoic mammals, with notes on the localities where they are known and comments on their likely mode of life. Complete species lists are included.     

Ordovician eunicid polychaetes of Estonia and surrounding areas: review of their distribution and diversification

Scolecodonts, the jaws of polychaete worms, are common and diverse palynomorphs in the Ordovician rocks of Estonia and surrounding areas. Some 120 apparatus-based species representing about 40 genera have been recorded thus far. Relatively long stratigraphical ranges of the majority of species reflect a low rate of evolution of jawed polychaetes. However, some individual species, as well as structural changes in the assemblages, appear to be useful for stratigraphical purposes. Environmental events like those in the middle Caradoc and late Ashgill had some impact on polychaete faunas, but less than on several other groups. In order to study the spatial distribution of eunicids, faunas of particular intervals of the Ordovician were investigated. Quantitative analysis revealed that polychaete assemblages with a very consistent qualitative and quantitative composition were widespread over long distances within the belts of similar facies conditions in the Baltoscandian Palaeobasin. On the other hand, it appears that species of Ordovician jawed polychaetes were strongly influenced by particular facies, and accordingly well differentiated along the palaeobasin gradient. The decrease in diversity and abundance towards the deeper-water part of the palaeobasin indicates that the majority of Ordovician eunicids preferred relatively shallow-water conditions. The increase in differentiation of environments is accompanied by an increase in differentiation of polychaete assemblages.     

Révision systématiquedu genre Steginoporella smitt, 1873 (Bryozoa Cheilostomata)

Systematic revision of the genus Steginoporella: until now about eighty species were described. Only twenty recent species and thirty-four fossil ones are maintained. Several species and subspecies are new.The main interest of this revision is to establish a biostratigraphical scale: the settlement of this scale is based on the known stratigraphical distribution and on an attempt of phylogeny.The second advantage is ecological: all recent species live in marine tropical environment. The Steginoporella are good paleoecological indicators.At last, the establishment of a paleobiogeography, even incomplete and not definitive, allows to understand more easily recent distribution of Steginoporella connected with the great events of earth evolution.     

THE DISTRIBUTION OF HYALINEA BALTHICA AND GLOBOROTALIA TRUNCATULINOIDES IN THE TYPE CALABRIAN

The stratigraphical distribution of the Foraminifera Hyalinea balthica (Schroeter) and Globorotalia truncatulinoides (d'Orbigny) in the type sections in southern Italy for the Calabrian Stage is described. It is shown that these species (and Arctica [ Cyprina ] islandica ) do not appear simultaneously at the base of the Pleistocene in the area.     

Fossilführung und Palökologie des lagunären Massenkalkes (Devon) im Sauerland (Rheinisches Schiefergebirge)

The Massenkalk north of Brilon (East-Sauerland) and north of Balve (West-Sauerland) is of lagoonal character and is Upper Givetian (Middle Devonian) in age. Stromatoporoids, which can be subdivided into different growth forms (spherical to tabular, encrusting, thin laminar, branching), are the main reef building organisms. The species of the branching stromatoporoidAmphipora, which are hard to distinguish, dominate. The two thin laminar speciesStromatopora cygnea Stearn 1963 andStachyodes (Keega) jonelrayi Stearn 1975 are described for the first time from Western Europe. Tabulate corals represent about 20 % of the reef-builders and permit important inferences about the restriction of environment. Rugose corals and calcareous algae are rare. Reef dwelling organisms are less important; among these brachiopods, molluscs, foraminifera, calcispheres, and ostracods are, however, widespread. - Several associations of reef-builders that depend on different water depths can be distinguished. Their composition varies according to the restriction of environment. With increasing water depth water energy increased on the carbonate platform. The analysis of the stratigraphical distribution of the species of the reef-builder fauna allows no more but vague stratigraphical classifications.     

Strontium isotope stratigraphy of Cretaceous hippuritid rudist bivalves: rates of morphological change and heterochronic evolution

Strontium isotope stratigraphy of 17 localities of rudist formations in the region of the former Mediterranean Tethys has provided a reliable and precise stratigraphical frame for the evaluation of morphological change in hippuritid rudist bivalves during the Coniacian–Campanian. The phyletic lineage Vaccinites cornuvaccinum (Bronn)–Vaccinites chaperi (Douvillé) evolved from the Early Coniacian until the Early Campanian and is characterized by phyletic size increase and allometric growth, as shown by morphometrical measurements of 102 shells. These chronospecies intergrade in the Late Coniacian so that V. cornuvaccinum is considered to be a reliable marker species for the Coniacian. The taxonomy of Vaccinites alpinus (Douvillé) is discussed and the species is recognized as a senior synonym of Vaccinites ultimus (Milovanovi ). It appears first in the Late Santonian and the last appearance is probably in Late Campanian. Both lineages are characterized by phyletic size increase and peramorphic evolution involving hypermorphosis. A doubling of the length of the mantle margin occurred within 5 m.y. in both lineages. The results demonstrate that the combination of morphometric analyses and stratigraphical precision provides an important tool for the delineation of tempo and mode of evolution in rudist bivalves. Strontium isotope stratigraphy resulted in a considerable revision of the ranges of the species investigated. As the stratigraphy of many Tethyan carbonate platforms relies on the distribution of rudist bivalves, and the species investigated are abundant in many rudist formations, the history of many Late Cretaceous carbonate platforms must be re-evaluated.     

A New Late Silurian or Early Devonian Thelodont from the Boothia Peninsula, Arctic Canada

Isolated scales of Boothialepis thorsteinssoni gen. et sp. nov. are described from a fossiliferous calcareous dolomite at the base of the Somerset Island Formation of the Boothia Peninsula, Arctic Canada. A new family, Boothialepididae (Thelodonti), is established on features of the scale morphology and histology. The new genus and species are distinguished by characteristics of crown sculpture, neck, and unusual size of the base. Two other thelodonts, Nikolivia elongata Karatajūtė-Talimaa and Canonia grossi Vieth, and an acanthodian, Poracanthodes sp., are described from the same stratigraphical level. Thelodonts have not previously been described from the Boothia Peninsula. Conodont-based correlation indicates a Late Silurian age for the base of the Somerset Island Formation on the Boothia Peninsula. Correlation of the beds with precisely dated microvertebrates in the Read Bay section on Cornwallis Island enables the age of the horizon with the new species to be determined as Early Devonian.     

Le plus grand représentant du genre Eomys (Rodentia,Mammalia) de l'Oligocène de l'Europe: Eomys huerzeleri nov. sp.

Eomys huerzeleri, a new species of Eomyidae already recognized and named by H.G. Stehlin but never published is described and compared with Eomys majorFreudenberg. The stratigraphical range of both species is discussed.     

A new high-resolution planktic foraminiferal zonation and subzonation for the lower Danian

A new planktic foraminiferal zonation has been established for the lower Danian, based on some of most expanded and continuous pelagic sections known to date (from Spain, Tunisia and Mexico). This biozonation is considered valid for low and middle latitudes. The maximum stratigraphical distribution of the index-species approximately coincides in all the studied sections. The index-species are abundant and easily recognizable. We propose the following biozones and subzones: Guembelitria cretacea Zone and the Hedbergella holmdelensis and Parvularugoglobigerina longiapertura subzones; the Parvularugoglobigerina eugubina Zone, which is subdivided into the Parvularugoglobigerina sabina and Eoglobigerina simplicissima subzones and the Parasubbotina pseudobulloides Zone with the Eoglobigerina trivialis and Subbotina triloculinoides subzones. A biomagnetostratigraphic correlation and calibration of the stratigraphical ranges of these species suggest that the biohorizons used to define the new biozonation are very isochronous, at least in the geographical areas analysed.     

Les sporophylles de Lepidodendron dissitum Sauveur, 1848

One specimen belonging to the arborescent lycopod stem species Lepidodendron dissitum SAUVEUR was found in connection with sporophylls named Lepidophyllum anthemis (KÖNIG) JONGMANS, species of a great stratigraphical and geographical range during the Upper Carboniferous, and specially abundant in the Spanish Stephanian. These two parts from the same plant are described and discussed in detail.     

The first ctenosauriscid (Reptilia: Archosauromorpha) from the Lower Triassic Of Eastern Europe

A new Early Triassic thecodont from the Donskaya Luka locality is described. A new species and genus of Rauisuchidae, Bystrowisuchus flerovi gen. et sp. nov., the first East European and earliest known member of the family Ctenosauriscidae is established. The taxonomy and phylogeny of Rauisuchidae and their stratigraphical and geographical distribution in connection with new finds are discussed.     

克罗地亚三叠纪粗枝藻组合的述评

对克罗地亚中三叠统和上三叠统的粗枝藻属化石组合的分析,侧重于特定的种和相关化石的地层分布方面。该分析显示这些藻类化石可以用来对这个时间段内的地层的细分。     

Contribution a l'etude biostratigraphique du Cretace superieur d'une coupe du Massif du Braus (Aples Maritimes,SE France)

The Cretaceous beds of the “Massif du Braus” contains a rich planctonic microfauna. A biostratigraphic study of this country is precised from Lower Cenomanian to Middle Campanian. Planktonic forminifera and Nannoplankton assemblages and events recognized in a continuous section in the “Massif du Braus” are given and discussed. The stratigraphical distribution of the different species is presented in three figures.     

The impact of fossil stratigraphic ranges on tip-calibration,and the accuracy and precision of divergence time estimates

The molecular clock provides the only viable means of establishing realistic evolutionary timescales but it remains unclear how best to calibrate divergence time analyses. Calibrations can be applied to the tips and/or to the nodes of a phylogeny. Tip-calibration is an attractive approach since it allows fossil species to be included alongside extant relatives in molecular clock analyses. However, most fossil species are known from multiple stratigraphical horizons and it remains unclear how such age ranges should be interpreted to codify tip-calibrations. We use simulations and empirical data to explore the impact on precision and accuracy of different approaches to informing tip-calibrations. In particular, we focus on the effect of using tip-calibrations defined using the oldest vs youngest stratigraphic occurrences, the full stratigraphical range, as well as confidence intervals on these data points. The results of our simulations show that using different calibration approaches leads to different divergence-time estimates and demonstrate that concentrating tip-calibrations near the root of the dated phylogeny improves both precision and accuracy of estimated divergence times. Finally, our results indicate that the highest levels of accuracy and precision are achieved when fossil tips are calibrated based on the fossil occurrence from which the morphological data were derived. These trends were corroborated by analysis of an empirical dataset for Ursidae. Overall, we conclude that tip-dating analyses should, in particular, employ tip calibrations close to the root of the tree and they should be calibrated based on the age of the fossil used to inform the morphological data used in Total Evidence Dating.