Distinctive Fossil Research Articles

Cretaceous chloranthoids: early prominence, extinct diversity and missing links.

The Chloranthaceae comprise four extant genera (Hedyosmum, Ascarina, Chloranthus and Sarcandra), all with simple flowers. Molecular phylogenetics indicates that the Chloranthaceae diverged very early in angiosperm evolution, although how they are related to eudicots, magnoliids, monocots and Ceratophyllum is uncertain. Fossil pollen similar to that of Ascarina and Hedyosmum has long been recognized in the Early Cretaceous, but over the last four decades evidence of extinct Chloranthaceae based on other types of fossils has expanded dramatically and contributes significantly to understanding the evolution of the family. Studies of fossils from the Cretaceous, especially mesofossils of Early Cretaceous age from Portugal and eastern North America, recognized diverse flowers, fruits, seeds, staminate inflorescences and stamens of extinct chloranthoids. These early chloranthoids include forms related to extant Hedyosmum and also to the Ascarina, Chloranthus and Sarcandra clade. In the Late Cretaceous there are several occurrences of distinctive fossil androecia related to extant Chloranthus. The rich and still expanding Cretaceous record of Chloranthaceae contrasts with a very sparse Cenozoic record, emphasizing that the four extant genera are likely to be relictual, although speciation within the genera might have occurred in relatively recent times. In this study, we describe three new genera of Early Cretaceous chloranthoids and summarize current knowledge on the extinct diversity of the group. The evolutionary lineage that includes extant Chloranthaceae is diverse and abundantly represented in Early Cretaceous mesofossil floras that provide some of the earliest evidence of angiosperm reproductive structures. Extinct chloranthoids, some of which are clearly in the Chloranthaceae crown group, fill some of the morphological gaps that currently separate the extant genera, help to illuminate how some of the unusual features of extant Chloranthaceae evolved and suggest that Chloranthaceae are of disproportionate importance for a more refined understanding of ecology and phylogeny of early angiosperm diversification.

Depositional history of Devonian to lower Carboniferous (Tournaisian) strata, northern Wyoming and southern Montana, USA

The lower Frasnian (Upper Devonian) Maywood Formation records incision of valleys into lower Paleozoic bedrock in fluvial to estuarine settings in northern Wyoming and deposition in estuarine to marine environments in southern Montana (USA). A distinctive fossil assemblage of microconchids, plant compression fossils, fish fossils, and microspores represent fauna and flora that lived in, and adjacent to, salinity-stressed ecological niches in the upper reaches of the Maywood valleys. A similar fossil assemblage is recorded in older Devonian valley-fill deposits of the Lower Devonian Beartooth Butte Formation, indicating that valley incision and subsequent transgression, occurred repeatedly over a span of nearly 30 million years with organisms tracking the marine incursions into the valleys. The fossil charcoal in the Maywood Formation captures a record of fire in adjacent terrestrial ecosystems. The amount of dioxygen (O2) was thus above the fire window level (16% by volume) and might have been near modern levels in the earliest Late Devonian atmosphere. The nearshore deposits of the Maywood Formation are overlain by extensive shallow carbonate shelf strata of the Jefferson Formation, likely resulting from a global transgression in the earliest Frasnian. A paired positive and negative δ13Ccarbonate [carb] isotopic excursion in the Jefferson with a range of >6‰ is a signal of the globally recognized “punctata” Event. The unconformably overlying Madison Limestone is lower Carboniferous, except for a thin basal Upper Devonian unit with marine palynomorphs. The Madison regionally records eastward transgression and establishment of widespread marine deposition. It also contains two positive δ13Ccarb excursions (up to ∼7.5‰) that make up the mid-Tournaisian (= Kinderhookian−Osagean boundary) carbon isotope excursion (TICE/KOBE). These isotope data provide a framework for regional and global correlation of northern Rocky Mountain strata and an archive of environmental and evolutionary change during the middle−late Paleozoic transition.

New records of fossil deep-sea shark teeth from the Lillebælt Clay (Early–Middle Eocene) of Denmark

This study describes for the first time a number of distinct fossil teeth documenting several deep-sea shark species from the Eocene, which were previously not recorded from the North Sea Basin, including Apristurus sp., Orthechinorhinus cf. pfeili, Deania cf. angoumeensis, Squaliolus sp., Etmopterus cf. cahuzaci and Paraetmopterus nolfi. Our findings significantly increase the deep-sea shark diversity documented from this area so far. Despite the fact that the North Sea Basin had already lost direct connections to the neighbouring marine areas in the Eocene, the fauna shows highest similarities with documented Eocene deep-sea faunas of France, Austria and northern Morocco using cluster analysis.

Pleistocene Caves of Eastern Sicily Coast: Exceptional Archives to Reconstruct the History of the Island’s Biota

The distinctive features and fossil content of some caves from eastern Sicily (San Teodoro, Donnavilla, Fulco, Taormina, Tremilia, Spinagallo), altogether spanning from the middle Pleistocene until the beginning of the Holocene, are discussed. Although dating on vertebrate and/or invertebrate remains is available in few instances, coastal notches and marine terraces correlate with the caves, provide further chronological constraint. The San Teodoro and Spinagallo caves are the best known, whereas the Tremilia cave deserves to be better analysed. Most caves, but not the San Teodoro one (including only terrestrial faunas), testify to the transition from submarine coastal environments (documented by biogenic crusts, borings, shelly sediments), to continental conditions (vertebrate remains of the Paleoloxodon falconeri, Maccagnone and San Teodoro Faunistic Complexes). The fossil register preserved in these cavities represents a source of information useful to (1) reconstruct the palaeogeography of Sicily and its coastline, largely resulting from the interplay between tectonic and sea-level changes linked to climate fluctuations; and (2) the consequent evolution of the terrestrial biota, including the dominance of insular endemic taxa later replaced by species shared with continental Italy, after the establishment of temporary connection through the Messina Strait.

Microstratigraphic Analysis of Fossil Distribution in the Lower Hornerstown and Upper Navesink Formations at the Edelman Fossil Park, NJ

Maastrichtian–Danian sediments of the Navesink and Hornerstown formations at the Jean and Ric Edelman Fossil Park of Rowan University in Mantua Township, New Jersey, have long intrigued paleontologists. Within the basal Hornerstown Formation occurs the Main Fossiliferous Layer (MFL), a regionally well-known and diverse bonebed. The lithostratigraphic and chronostratigraphic position of this fossil layer have been debated for more than 50 years, fueling debate over its origin. Herein, we present the results of a microstratigraphic analysis of the fossil composition and distribution of the MFL undertaken to rectify these discrepancies. Through methodical top-down excavation, we recorded the three-dimensional position of every fossil encountered. Three-dimensional visualization and analyses of these data in ArcGIS Pro yielded an unprecedented view of this bonebed. Most reported discrepancies about the stratigraphic placement and thickness of the MFL can be explained by the presence of two distinct fossil assemblages within this interval that are occasionally combined into a single bonebed. The stratigraphically-lower assemblage, herein termed an “oyster layer”, is geometrically-tabular and exhibits low taxonomic diversity, high abundance of the oyster Pycnodonte, and moderate taxonomic richness. The stratigraphically-higher assemblage, the MFL, occurs approximately 9 cm higher in section and exhibits high values of taxonomic diversity, fossil abundance, and taxonomic richness. Sedimentological homogeneity throughout this interval suggests that these faunal contrasts arise from the two assemblages having formed via independent taphonomic pathways. Specifically, prevalence of Pycnodonte in the oyster layer implies formation by a selective mortality event, whereas the diversity of the MFL appears to reflect a more universal agent of mortality. Spatial variations in the stratigraphic distribution of fossils within the MFL in our excavation area indicate this assemblage does not form a simple, tabular layer as previously thought and may, in part, record original bathymetry. Importantly, our definition of the MFL and detailed characterization of its stratigraphic placement are essential for future studies on the taphonomic origin and chronostratigraphy of this bonebed. Universal use of this definition would allow researchers to confidently elucidate the exact lithostratigraphic positions of precise chronostratigraphic indicators within the MFL and accurately estimate the degree of time averaging of its fossils.

Lake sedimentary DNA to reveal long-term changes in aquatic biodiversity and ecosystem functioning

The emergence of molecular analyses based on the sequencing of sedimentary DNA has opened up many new areas of inquiry in paleolimnology. DNA preserved in sediments (SedDNA) offers the possibility to consider taxa that were traditionally not accessible because they do not leave distinct morphological fossils. Recent applications that considered a diversity of biological groups (including bacteria, protists, zooplankton, fish) illustrate how efficiently SedDNA-based methods complement both classical paleolimnology proxies and limnological data. The knowledge gained from this approach is very diverse in scope, ranging from quantifying natural variability in population and community dynamics to understanding how these biological variables respond to anthropogenic disturbances and climatic change. The use of lake sedimentary DNA to track long-term changes in aquatic biota is a rapidly advancing field of research. Based on recent applications, this presentation illustrates (i) the potential and challenges associated with the study of SedDNA to address critical research questions in lacustrine ecology (ii) the main methodological precautions to be taken into account for implementing these types of DNA analyses (i.e. best practices) and (iii) the emerging topics that could be addressed using sedimentary DNA, in particular to reconstruct the temporal dynamics of lacustrine biodiversity.

Age constraints on surface deformation recorded by fossil shorelines at Cape Range, Western Australia

Abstract Laterally continuous terraces along the western flank of Cape Range, Western Australia, record both past sea-level highstands and postdepositional vertical displacement. Four distinct fossil coral reef terraces extend nearly the entire length of the slowly uplifting anticlinal structure (∼100 km), enabling documentation of the timing and degree of deformation-induced elevation contamination of past sea-level estimates from fossil shorelines. Here, we present detailed elevations of the four terraces using differential global positioning system (DGPS) and airborne light detection and ranging (LiDAR) data sets, along with new ages for the three upper terraces. Geochemical dating using strontium isotope stratigraphy techniques revealed, from highest to lowest elevation: a late Miocene reef terrace, a late Pliocene shoreline, and a prominent mid-Pleistocene reef terrace (probably associated with the marine oxygen isotope stage 33–31 interglacial), along with a broad last interglacial (Eemian) reef terrace and lagoon, which terminate at the modern shoreline. Laterally variable elevation data integrated with newly defined ages for the terraces demonstrate a gradual and continuous relative deformation in the region that spans at least the last 6.5 m.y. and constrains the emergence of the Cape Range to sometime prior to the late Miocene. This data set also shows that the most recent interglacial shoreline has undergone <1.3 m of vertical warping, suggesting minimal deformation since deposition. By tracing relative uplift rates over multiple terraces for ∼100 km of coastline, we placed constraints on maximum relative sea level (RSL) for the older terraces. Most notably, we were able to place strict maximum RSL elevations of <+34 m on the Pliocene terrace and <+16.5 m on the mid-Pleistocene terrace, with probable RSL being somewhat lower.

An updated review of the middle Eocene avifauna from the Geiseltal (Germany), with comments on the unusual taphonomy of some bird remains

The brown coal mines of the Geiseltal in Germany were among the most important middle Eocene fossil localities and constitute the reference sites for the Geiseltalian stage of the European Land Mammal Mega Zones. Here, an updated review of the Geiseltal avifauna is given. Thirteen species are represented by diagnostic bones and can be referred to avian higher-level taxa, but various indeterminable albeit distinct fossils indicate a higher diversity of the Geiseltal avifauna. The majority of the Geiseltal fossils belong to taxa, which are well known from early to mid-Ypresian fossil sites of Europe and North America. Some of the species from the Geiseltal are larger than their early Eocene relatives, but it remains elusive whether this indicates an evolutionary size increase in some avian lineages or reflects different palaeohabitats of the involved fossil sites. The Geiseltal avifauna exhibits some taphonomic peculiarities that have not yet been addressed. Most bird fossils consist of isolated bones or partial skeletons and here it is hypothesized that at least some of the fragmentary specimens represent feeding remains of crocodilians. For the first time, medullary bone, which is indicative of breeding females, is reported for birds from the Geiseltal. The comparative abundance of the coliiform species Eoglaucidium pallas is remarkable, and either this species was extremely abundant in the Geiseltal ecosystem or it had ecological preferences, which favored its preservation.

Different shades of green: Global oil and gas companies and renewable energy

The long-term energy transition from fossil fuels to renewable energy raises critical questions about the future of oil and gas firms. This study asks why some oil and gas firms are committed to renewable energy while others continue to maintain a distinct fossil fuels focus with little or no investment in renewable energy. The analysis reveals that there is a wide range in the degree to which oil and gas firms have invested in renewable energy. Some firms have no investments and others have investments in multiple renewable energy technologies across many countries. We examine a combination of country-based institutional factors and firm-based knowledge and experience factors that could impact oil and gas firms’ decisions to invest in renewable energy activity. Regulative and normative pressures impacted renewable energy investments as did environmental citizenship and the degree of internationalization. The study’s integration of country-level factors with firm-level experiences provides insights into how firms are dealing with the energy transition. By examining areas such as sustainability and regulatory policy, the paper sheds light on the ways in which scholars can tap into measures and methods that can extend traditional IB research.

Choice of Size Parameter Alters Interpretation of Fossil Hominin Distal Humeral Morphology

Allometric trends in human distal humeral morphology may account for a substantial portion of morphological variation observed among fossil hominins, affecting both taxonomic assessments and behavioral reconstructions. However, previous allometric studies have focused on the relationship of humeral morphology to size parameters of the distal humerus itself (i.e., centroid size), which is potentially confounded by interspecific differences in scaling of humeral dimensions to body mass, a factor that creates direct biomechanical demands on the forelimb in all non‐human primates.In this study, we compared the relationship between distal humeral centroid size and body mass in extant hominids (N=246 modern humans, 47 Pan, 44 Gorilla, 22 Pongo) and three fossil hominins (A.L. 288‐1, StW 431, KNM‐ER 1503/1504) where body mass could be estimated from femoral head size. We then scaled principal components extracted from geometric morphometric (GM) analyses of three regions of the distal humerus (articular, periarticular, and distal diaphyseal) by both body mass and centroid size in order to evaluate differences resulting from choice of size parameter. Finally, we analyzed the relationship of nine fossil hominins to humans of equivalent body mass (A.L. 288‐1, StW 431, KNM‐ER 1503/1504) and centroid size (KNM‐KP 271, A.L. 288‐1, StW 431, KNM‐ER 1504, KNM‐ER 739, SKX 10924, SK 24600, TM 1517, Gombore IB‐7594).While centroid size was highly correlated with body mass in all taxa (r=0.88–0.97), humans were highly positively allometric and had significantly smaller centroid sizes relative to body mass than other hominids, as did A.L. 288‐1 and KNM‐ER 1504. StW 431, however, showed a relationship between distal humeral size and body mass more similar to that seen in non‐human great apes. There was significant allometry in the traits differentiating modern humans and other hominids that resulted in large‐bodied humans showing more great ape‐like distal humeral characteristics than smaller humans in the articular and distal diaphyseal but not the periarticular region. This increased differences in size‐scaled morphology between modern humans and fossil hominins in several cases, most prominently A.L. 288‐1. The differences between humans and other hominids in the relationship of centroid size to body mass create the appearance of a distinct fossil hominin morphological group composed of A.L. 288‐1 and other small fossil humeri (SKX 10924, SK 24600) when principal components extracted from the GM analyses are regressed on centroid size. When body mass is used as the independent variable for regression, however, this distinct fossil grouping disappears, and it becomes clear that this morphology is also seen in small‐bodied chimpanzees and orangutans.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

The Jurassic fossil wood diversity from western Liaoning, NE China

Western Liaoning is a unique region in China that bears diverse types of Jurassic plants, including leaves, fern rhizomes, and wood, providing significant proxy for vegetation and palaeoenvironment reconstruction of the well-known Yanliao Flora in East Asia. In particular, the silicified wood is very abundant in the fossil Lagerstätte of the Jurassic Tiaojishan Formation in Beipiao, western Liaoning. Previous and recent systematic investigations documented a high diversity of the Jurassic wood assemblages. These assemblages are dominated by conifers, followed by cycads and ginkgoaleans. In total, about 30 species belonging to 21 genera of fossil wood have been recorded so far, which are represented by Cycadopsida, Ginkgopsida, Coniferopsida, and Gymnospermae incertae sedis. The evolutionary implications of several distinctive fossil wood taxa as well as palaeoclimate implications are summarized based on their anatomical structures and growth ring patterns. This work approaches the vegetation development and evolutionary significances of the wood taxa and their relatives, and provides clues for the further understanding of the diversity of the Jurassic Yanliao Flora in East Asia.

Geomorphic History of the Beaver Creek Drainage Basin as Determined from Topographic Map Evidence: Eastern Montana and Western North Dakota, USA

The Beaver Creek drainage basin is located along the North Dakota-Montana border slightly to the south of a recognized continental ice sheet margin and immediately to the east of the deep northeast-oriented Yellowstone River valley with Beaver Creek flowing in a north and northeast direction to join the north-oriented Little Missouri River. The Beaver Creek drainage basin originates on an escarpment-surrounded upland and its erosional history was determined by analyzing detailed topographic maps aided by previously made field observations that showed coarse-grained and distinctive alluvium had been transported in an east direction across the Beaver Creek drainage basin and across what is now the deep Little Missouri River valley to sediments making up southwest North Dakota high points containing both the distinctive alluvium and Oligocene age fossils. Drainage divides surrounding the Beaver Creek drainage basin show numerous divide crossings (or notches) linking northwest-oriented Yellowstone River tributary valleys with east-oriented Beaver Creek tributary valleys and west- or northwest-oriented Beaver Creek tributary valleys with southeast- or east-oriented Little Missouri River tributary valleys and suggest the Beaver Creek valley eroded headward across a large-scale flood formed anastomosing channel complex. Buttes located just to the east of the Beaver Creek-Little Missouri River drainage divide suggest the east-oriented water removed as much as 150 meters, or more, of Beaver Creek drainage basin bedrock, and even greater amounts of bedrock from regions to the south of the Beaver Creek drainage basin. Topographic map evidence and routes traveled by the distinctive alluvium suggest a continental ice sheet blocked a large and high-level northeast-oriented river and diverted at least some of the water along the ice sheet margin with the east-oriented floodwaters being captured in a progressive sequence by headward erosion of the Little Missouri River, Beaver Creek, and Yellowstone River valleys (in that order).

Influence of redox conditions on animal distribution and soft-bodied fossil preservation of the Lower Cambrian Chengjiang Biota

The exceptionally preserved Chengjiang Biota (Yunnan, China) is significant for understanding the rapid development of complex animal-rich ecosystems during the evolutionary radiation of the Cambrian. However, the ecological signal provided by the fossils captured in this deposit may not reflect accurately the in-life community, with transport and decay of carcasses being the principal processes responsible for potential modification. The principal fossil-bearing interval (Maotianshan Shale Member, Yu'anshan Formation) is comprised of claystones of two distinct depositional origins: the “background” beds represent slow hemipelagic deposition into deep waters, while the “event” beds represent distal turbidites or storm-generated beds. Each bed type has a distinct fossil assemblage and preservation mode underscoring the importance of interpreting the palaeoenvironment of each bed type. Here, we interpret palaeo-redox conditions for both the background beds and the event beds by conducting a systematic geochemical study using iron speciation, δ34Spy, δ13Ccarb,δ13CTOC and molybdenum abundance. These data are from the most complete core recovered from the Chengjiang fossiliferous units and allow us to distinguish redox conditions where the animals lived, and where they were buried and exceptionally preserved. Our results demonstrate that background beds were dominated by dysoxic conditions; here, a diverse sponge community tolerant of low-oxygen conditions lived. In contrast, the shallower shelf and offshore-transitional environments, where event beds were sourced, were almost persistently oxic, and it was here where the diverse Chengjiang Biota flourished. Thus, the Chengjiang sediments record two distinct palaeocommunities within the background and the event beds. The contrasting redox conditions in close spatial proximity likely facilitated the soft-bodied fossil preservation. Our findings provide a valuable case study in the necessity to understand ecological composition and exceptional preservation informed by environmental context.

The fossilized birth-death model for the analysis of stratigraphic range data under different speciation modes

A birth-death-sampling model gives rise to phylogenetic trees with samples from the past and the present. Interpreting “birth” as branching speciation, “death” as extinction, and “sampling” as fossil preservation and recovery, this model – also referred to as the fossilized birth-death (FBD) model – gives rise to phylogenetic trees on extant and fossil samples. The model has been mathematically analyzed and successfully applied to a range of datasets on different taxonomic levels, such as penguins, plants, and insects. However, the current mathematical treatment of this model does not allow for a group of temporally distinct fossil specimens to be assigned to the same species.In this paper, we provide a general mathematical FBD modeling framework that explicitly takes “stratigraphic ranges” into account, with a stratigraphic range being defined as the lineage interval associated with a single species, ranging through time from the first to the last fossil appearance of the species. To assign a sequence of fossil samples in the phylogenetic tree to the same species, i.e., to specify a stratigraphic range, we need to define the mode of speciation. We provide expressions to account for three common speciation modes: budding (or asymmetric) speciation, bifurcating (or symmetric) speciation, and anagenetic speciation.Our equations allow for flexible joint Bayesian analysis of paleontological and neontological data. Furthermore, our framework is directly applicable to epidemiology, where a stratigraphic range is the observed duration of infection of a single patient, “birth” via budding is transmission, “death” is recovery, and “sampling” is sequencing the pathogen of a patient. Thus, we present a model that allows for incorporation of multiple observations through time from a single patient.

On the nomenclature of fossil Aspleniopteris, Carpinicarpus, Comptonia, Comptoniphyllum and Dryandrophyllum (Myricaceae)

AbstractComptonia comptoniifolia(Brongn.) Doweld, comb. nov., based on the recently rediscoveredPhyllites comptoniifoliusBrongn., is reinstated based upon priority as the earliest validly published species name in place of the previously incorrectly usedC. acutilobaBrongn. andC. difformis(Sternb.) E.W. Berry (Aspleniopteris difformisSternb.;Asplenium difformeSternb. non R. Br.).Comptonia japonicaKrysht. is shown to be the earliest validly published name instead of the previously widely acceptedComptoniphyllum naumanniiNath. A new genus,Paracomptoniagen. nov., is proposed instead of the previously invalidly publishedDryandrophyllumVelen., being based on the formerly segregatedComptoniasubg.AvushiaZhilin, with transference of two CretaceousDryandraspecies,D. cretacea, andD. yakovlevii, and one Palaeogene species,D. schrankii, intoParacomptonia. The aberrant fossil species of Western SiberianComptonia, based on fruit endocarps with a superficial resemblance to the extant genus, are reclassified and transferred into the recircumscribed and amplified distinct fossil genusCarpinicarpus, which is reinstated as a validly published genus instead of the anomalousComptoniasection †ComptoniellaP.I. Dorof.:Carpinicarpus debilis(V.P. Nikit.) Doweld, comb. nov.,C. dorofeevii(V.P. Nikit.) Doweld, comb. nov.,C. gorbunovii(P.I. Dorof.) Doweld, comb. nov., andC. tymensis(P.I. Dorof.) Doweld, comb. nov.Comptonia japonicais neotypified;Paracomptonia cretacea(Velen.) Doweld comb. nov.,P. yakovlevii(Palib.) Doweld, comb. nov. andP. schrankii(Sternb.) Doweld,comb. nov. are lectotypified for the first time.

A review of the nomenclature of Cyclostigma (Cyclostigmatales: Cyclostigmataceae; fossil Isoetophyta)

AbstractThe complicated nomenclatural history of the extinct genus Cyclostigma Haught., established for arborescent trunks of presumably ancient isoetopsids (Isoetophyta: Cyclostigmatales), is reviewed and corrected with newly found bibliographic and historical data. The fossil name Cyclostigma, an illegitimate later homonym of two extant angiosperm genera, Cyclostigma Hochst. ex Endl. (Apocynaceae) nec Cyclostigma Klotzsch (Euphorbiaceae), was recently conserved and listed in App. III of ICN since the XVIII IBC in 2011. The fossil generic name Cyclostigma, associated with three species epithets and a distinct fossil family name Cyclostigmataceae (“Cyclostigmeae”), was invalidly published by Haughton in his series of works of 1859 and 1860 (reprinted several times), the genus lacking a description. Haughton’s family name based on his “Cyclostigma” and the species published in this genus were also not validly published. However, the generic name Cyclostigma was validly published in a little‐known publication by Haughton in 1859, not by Heer in 1871, as generally accepted in modern systematic palaeobotany, or Baily in 1861. In course of thorough nomenclatural analysis it has been shown that three fossil species names, which fell into oblivion still in the early works in the 19th century, Sigillaria dichotoma Haught. 1855, Lepidodendron griffithii Brongn. 1857 and L. minutum Haught. 1855 (non Sauveur) have priority over Cyclostigma kiltorkense Haught. 1859. Since C. kiltorkense has entered solidly into systematic palaeobotany and served as an index marker in historical geology, its retention through conservation is proposed. The nomenclature of the name Cyclostigmataceae is corrected as to be first validly published by Haughton in 1860.

Stratigraphic distribution, taphonomy and paleoenvironments of Spinicaudata in the Triassic and Jurassic of the Paraná Basin

Due to the chitino-phosphatic nature of Spinicaudata conchostracan exoskeletons, their carapaces exhibit a low preservational potential compared to other bivalve groups. However, the recent studies point towards the increased tolerance of the carapace against the physical processes. Due to this peculiar characteristic, conchostracan carapace have been utilized as precise temporal markers in estimating stratigraphic and taphonomic parameters. The same characteristic also makes the spinicaudatans useful in evaluating the depositional processes and environments. The present work aims at providing a paleoenvironmental and stratigraphic analysis of conchostracans (Spinicaudata) from the Triassic-Jurassic of the Paraná Basin (Santa Maria and Caturrita formations) in terms of the sedimentary facies analysis, depositional system characterization, and analysis of the taphonomic signatures of the fossiliferous horizons within these formations. The results from the taphonomic study delineates the presence of 4 distinct fossil assemblages based on the causative mechanism and fundamental characteristics of the fossil concentrations: two taphonomic assemblages in the laminated mudstone beds deposited from the decanting fine-grained sediments in floodplains; the sandstone beds with plane parallel laminations and dune- and ripple-cross-stratifications deposited from the flooding-related overflow in the floodplains; and the association of laminated mudstone and massive sandstone beds deposited as the river mouth bars. The results show that the taphonomic signatures, e.g., closed valves, may indicate the various patterns of autochthony and allochthony. In the fine-grained floodplain assemblages, the high degree of preservation can be attributed to autochthony in the conchostracans, whereas the preservational condition of floodplain sandstone sheet and mouth bar assemblages point toward parautochthony and even allochthony. Therefore, the preservational quality of conchostracan exoskeletons is likely a function of parameters, e.g., the transport duration, the distance from life position, and the magnitude of events causing their final burial. Within the observed species, the recognition of Eustheria minuta in the stratigraphic level of the Passo das Tropas creek corroborates an age for these deposits between the late Middle Triassic and early Upper Triassic. The presence of a new form, likely related to the family Fushunograptidae in sediments from the Caturrita Formation, suggests a Jurassic age for these deposits.

The Contribution of Fossils to Chronostratigraphy, 150 Years after Albert Oppel

The 150th anniversary of the death of Albert Oppel (1831–65) provided the opportunity to celebrate this outstanding stratigrapher with a Thematic Issue dedicated to the importance of fossils for dating and correlating of sedimentary rocks. In this issue, we analyse Oppel's significant contribution to modern chronostratigraphy, before exploring the Phanerozoic through all its major fossil groups, to verify if fossils are still able to make a significant contribution to chronostratigraphy. The extraordinary merit of Oppel's work has been the demonstration that fossils can be used to sub-divide sedimentary sequences into zones, which in turn might be organized in higher chronostratigraphical units. The zone for Oppel is characterized by the distinctive fossil content, and his view strongly influenced the development of the standard chronostratigraphical scale for about one century, until the introduction, in the 1950s, of the log-based range chart as the common practice to study the fossil record of sedimentary successions. This approach forced the stratigraphers to shift the focus from the fossil content of the zones to their boundaries. This new view allowed for the introduction of new kind of zones with precisely defined boundaries based on bioevents and to the decline of the Oppel Zone. This turning point in the history of chronostratigraphy was fuelled by the International Commission on Stratigraphy programme of definition of the units of the International Chronostratigraphic Chart based on the boundary stratotype and point (GSSP) concept, which started in 1973.

Myrteae phylogeny, calibration, biogeography and diversification patterns: Increased understanding in the most species rich tribe of Myrtaceae

Myrteae (c. 2500 species; 51 genera) is the largest tribe of Myrtaceae and an ecologically important groups of angiosperms in the Neotropics. Systematic relationships in Myrteae are complex, hindering conservation initiatives and jeopardizing evolutionary modelling. A well-supported and robust phylogenetic hypothesis was here targeted towards a comprehensive understanding of the relationships within the tribe. The resultant topology was used as a base for key evolutionary analyses such as age estimation, historical biogeography and diversification rate patterns. One nuclear (ITS) and seven chloroplast (psbA-trnH, matK, ndhF, trnl-trnF, trnQ-rps16, rpl16 and rpl32-trnL) DNA regions for 115 taxa representing 46 out of the 51 genera in the tribe were accessed and analysed using maximum likelihood and Bayesian inference tools for phylogenetic reconstruction. Dates of diversification events were estimated and contrasted using two distinct fossil sets (macro and pollen) in BEAST. The subsequent dated phylogenies were compared and analysed for biogeographical patterns using BioGeoBEARS and diversification rates using BAMM. Myrteae phylogeny presents strong statistical support for three major clades within the tribe: Australasian group, Myrtus group and Main Neotropical Lineage. Dating results from calibration using macrofossil are an average of 20 million years older and show an early Paleocene origin of Myrteae, against a mid-Eocene one from the pollen fossil calibration. Biogeographic analysis shows the origin of Myrteae in Zealandia in both calibration approaches, followed by a widespread distribution throughout the still-linked Gondwana continents and diversification of Neotropical endemic lineages by later vicariance. Best configuration shift indicates three points of acceleration in diversification rates, all of them occurring in the Main Neotropical Lineage. Based on the reconstructed topology, several new taxonomic placements were recovered, including: the relative position of Myrtus communis, the placement of the Blepharocalyx group, the absence of generic endemism in the Caribbean, and the paraphyletism of the former Pimenta group. Distinct calibration approaches affect biogeography interpretation, increasing the number of necessary long distance dispersal events in the topology with older nodes. It is hypothesised that biological intrinsic factors such as modifications of embryo type and polyploidy might have played a role in accelerating shifts of diversification rates in Neotropical lineages. Future perspectives include formal subtribal classification, standardization of fossil calibration approaches and better links between diversification shifts and trait evolution.

Protaeropsis, a new replacement generic name for fossil Sphenaster Jeffery, 1999 (Echinoidea: Spatangida) nec Wilcoxon, 1970 (Protista: Haptomonada).

The genus Sphenaster was erected by Jeffery (in Smith et al. 1999: 131) for a distinctive fossil echinoid of the Thanetian (Palaeocene) age from Spain and considered to be the most ancient element of the echinoid family Aeropsidae Clark, 1917 (Spatangida, Echinoidea). Unfortunately, up to now (Kroh 2010), it was not realized that the generic name Sphenaster is invalid, being a junior homonym of Sphenaster Wilcoxon, 1970: 80, a genus of fossil protist (Haptomonada).