Palaeontology

Aim: Winteraceae comprise c. 130 species in seven genera, with the greatest species diversity in the Pacific (Pseudowintera, Zygogynum), Australia (Bubbia, Tasmannia), New Guinea (Belliolum, Bubbia, Zygogynum, Tasmannia) and Madagascar (Takhtajania). Only Drimys occurs in South America. Because of their Cretaceous leaves, wood and pollen fossils, and their lack of xylem vessels, Winteraceae throw light on early angiosperm evolution. We describe a Winteraceae pollen tetrad from the Paleocene of Greenland, review the family’s fossil record and palaeogeography and document its current climate preferences.
Location: Worldwide.
Methods: Extant and fossil pollen were studied with light and scanning electron microscopy. Molecular phylogenetic and character mapping approaches were used to infer the evolution of pollen characters, and 37,842 collections from the Global Biodiversity Information Facility were used to infer the climate and vegetation types occupied by today’s Winteraceae and to compare them to the Paleocene climate
and vegetation of Greenland as inferred from the fossil record of other families.
Results: Winteraceae are the only flowering plants with persistent, acalymmate tetrads composed of ulcerate grains with a distinct reticulate sculpturing. The tetrad described here as Pseudowinterapollis agatdalensis Grímsson & Zetter spec. nov. comes from Agatdalen valley in western Greenland and dates to the Early Paleocene, Danian, 64–62 Ma. It shows the complete character suite of modern Winteraceae
and overlaps the LM characters of the three previously known
Pseudowinterapollis species from Australia, New Zealand and South Africa. The palaeoflora of the Agatdal Formation consisted of a mixed deciduous–evergreen forest resembling habitats where Winteraceae occur today. Main conclusions: Macro- and microfossil records of Winteraceae extend back to the Upper Cretaceous in both Laurasia and Gondwana, and the family’s biogeography, like that of its sister family, Canellaceae, cannot be understood by focusing only on southern Gondwana. Winteraceae instead were part of broadleaved forests
in Paleocene and Eocene North American and Greenland and may have reached Europe via the North Atlantic Land Bridge, explaining Eocene Winteraceae wood in northern Germany.

The Aglaspidida is a major group of Palaeozoic arthropods traditionally regarded as problematic, but whose evolutionary history has attracted renewed attention over the last decade. These efforts have resulted in an improved understanding of various aspects of aglaspidid palaeobiology, including their environmental, geographical and stratigraphical distribution, and phylogenetic relationships. Here, we describe a new weakly biomineralized non-trilobite arthropod from the Furongian Guole Konservat-Lagerstätte (Sandu Formation) in South China that contributes towards a more complete reconstruction of aglaspidid evolution and diversity during the late Cambrian. Beckwithia? gracilis n. sp. resembles the type species B. typa in the possession of a reentrant posterior cephalic margin, general trunk appearance and coarse tuberculation, but differs in having a more slender construction and a homogeneous exoskeletal sculpture. A revision of putative Beckwithia from Australia and Russia argues against their inclusion in this taxon, making the new species the only representative of the genus outside Laurentia. After Aglaspella and Glypharthrus, also from the Guole biota, this is the third aglaspidid genus shared between Laurentia and South China, which supports the hypothesis that some aglaspidids had great dispersal capabilities.

Using a relatively inexpensive stereomicroscope that includes a built-in digital camera, together with the freeware ImageJ image processing package, reasonable quality digital images can be produced of miniscule fossil insects found in Baltic amber dating from the middle Eocene epoch.

The Randeck Maar lake sediments from SW Germany were deposited during a climatic phase known as the Mid‐Miocene Climatic Optimum, providing a unique window into this last favourable period for a more thermophilous fauna in Central Europe. Previous palaeoecological reconstructions of Randeck Maar's environment focused on the flora and vertebrate fauna. Here, we present a palaeoecological analysis using gastropods as proxies by means of an actualistic genus‐level approach. This approach is grounded in comparisons of habitat preferences between extant and fossil congeners and thus obviously requires a sound taxonomic framework. Despite being commonly applied in the literature, this approach has hardly been defined so far. Therefore, we thoroughly delineate it, exploring its applicability, potential and shortcomings. The molluscan fauna of Randeck Maar counts with 32 species of continental snails, mostly terrestrial pulmonates, related to the following palaeohabitats: littoral, supralittoral, rocky walls, shrubland, forests and open habitats. The gastropods indicate a warm‐temperate climate with a dry season, in line with previous works on Randeck Maar's flora and vertebrates.

The skeletons of teleost fishes dominate the Tithonian ichthyotaphocoenosis from the Mörnsheim Formation of Bavaria. Analysis of
skeletal distribution, deformations of the vertebral column, and evidence of benthic currents originated from the long-term accumulation
of carcasses in the plattenkalk under low sedimentation rates with evidence of prolonged exposure at the sediment-water interface. The
spatial arrangement of disarticulated skeletal elements of fishes in the Mörnsheim resulted from the decay of soft tissues at the burial
place in a calm environment. Disarticulation of some fishes as well as the convex-up arrangement of bivalve valves and ammonite aptychi
may indicate weak current activity. Unlike other plattenkalk localities, there is no conclusive evidence of mass mortality. This suggests
that the Mörnsheim Formation was subject to weak bottom currents indicating more open-marine circulation compared to the Solnhofen
Formation.

Assessments of dinosaur macroevolution at any given time can be biased by the historical publication record. Recent studies have analysed patterns in dinosaur diversity that are based on secular variations in the numbers of published taxa. Many of these have employed a range of approaches that account for changes in the shape of the taxonomic abundance curve, which are largely dependent on databases compiled from the primary published literature. However, how these ‘corrected’ diversity patterns are influenced by the history of publication remains largely unknown. Here, we investigate the influence of publication history between 1991 and 2015 on our understanding of dinosaur evolution using raw diversity estimates and shareholder quorum subsampling for the three major subgroups: Ornithischia, Sauropodomorpha, and Theropoda. We find that, while sampling generally improves through time, there remain periods and regions in dinosaur evolutionary history where diversity estimates are highly volatile (e.g. the latest Jurassic of Europe, the mid-Cretaceous of North America, and the Late Cretaceous of South America). Our results show that historical changes in database compilation can often substantially influence our interpretations of dinosaur diversity. ‘Global’ estimates of diversity based on the fossil record are often also based on incomplete, and distinct regional signals, each subject to their own sampling history. Changes in the record of taxon abundance distribution, either through discovery of new taxa or addition of existing taxa to improve sampling evenness, are important in improving the reliability of our interpretations of dinosaur diversity. Furthermore, the number of occurrences and newly identified dinosaurs is still rapidly increasing through time, suggesting that it is entirely possible for much of what we know about dinosaurs at the present to change within the next 20 years.

Conodont fossils are highly valuable for Paleozoic biostratigraphy and for interpreting evolutionary change, but identifying and describing conodont morphologies, and characterizing gradual shape variation remain challenging. We used geometric morphometric (GM) analysis to conduct the first landmark-based morphometric analysis of the biostratigraphically useful conodont genus Neognathodus. Our objective is to assess whether previously defined morphotype groups are reliably distinct from one another. As such, we reevaluate patterns of morphologic change in Neognathodus P1elements, perform maximum-likelihood tests of evolutionary modes, and construct novel, GM-based biozonations through a Desmoinesian (Middle Pennsylvanian) section in the Illinois Basin. Our GM results record the entire spectrum of shape variability among Neognathodus morphotypes, thus alleviating the problem of documenting and classifying gradual morphologic transitions between morphotypes. Statistically distinct GM groups support previously established classifications of N. bassleri, N. bothrops, and N. roundyi. Statistically indistinct pairs of GM groups do not support literature designations of N. medadultimus and N. medex-ultimus, and N. dilatus and N. metanodosus, and we synonymize each pair. Maximum-likelihood tests of evolutionary modes provide the first statistical assessment of Neognathodus evolutionary models in the Desmoinesian. The most likely evolutionary models are an unbiased random walk or a general random walk. We name four distinct biozones through the Desmoinesian using GM results, and these align with previous biozonation structure based on the Neognathodus Index (NI), illustrating that Neognathodus-based biostratigraphic correlations would not change between GM or NI methods. The structural similarity between both biozonations showcases that determining GM-based biozones is not redundant, as this comparison validates using landmark-based GM work to construct viable biozonations for subsequent stratigraphic correlations. Although this study is limited to the Illinois Basin, our quantitative methodology can be applied broadly to test taxonomic designations of additional genera, interpret statistically robust evolutionary patterns, and construct valid biozones for this significant chordate group.

Large, actively swimming suspension feeders evolved several times in Earth's history, arising independently from groups as diverse as sharks, rays and stem teleost fishes, and in mysticete whales. However, animals occupying this niche have not been identified from the early Palaeozoic era. Anomalocarids, a group of stem arthropods that were the largest nektonic animals of the Cambrian and Ordovician periods, are generally thought to have been apex predators. Here we describe new material from Tamisiocaris borealis, an anomalocarid from the Early Cambrian (Series 2) Sirius Passet Fauna of North Greenland, and propose that its frontal appendage is specialized for suspension feeding. The appendage bears long, slender and equally spaced ventral spines furnished with dense rows of long and fine auxiliary spines. This suggests that T. borealis was a microphagous suspension feeder, using its appendages for sweep-net capture of food items down to 0.5 mm, within the size range of mesozooplankton such as copepods. Our observations demonstrate that large, nektonic suspension feeders first evolved during the Cambrian explosion, as part of an adaptive radiation of anomalocarids. The presence of nektonic suspension feeders in the Early Cambrian, together with evidence for a diverse pelagic community containing phytoplankton and mesozooplankton, indicate the existence of a complex pelagic ecosystem supported by high primary productivity and nutrient flux. Cambrian pelagic ecosystems seem to have been more modern than previously believed.

You may discover a specimen in your collection that is suffering from pyrite decay and it may already appear to be too late to save it. However, a pile of ash-like substance in a card tray might look like it is destined only for the bin but careful cleaning and simple stabilisation techniques may reveal a useful specimen underneath. If so, record it as fully as possible as soon as possible using either traditional techniques (photography and/or moulding and casting) or by using modern techniques such as photogrammetry, CT scanning, Micro CT scanning or laser scanning  as the specimen will be prone to further deterioration in the future.

Pyrite oxidation (or pyrite decay) has been a problem in museum collections for many years. The damage to specimens can include total loss of the object and its label. There is no cure: the changes cannot be reversed but the process can be halted. Preventing pyrite oxidation in the first place is obviously preferable but maintaining the appropriate environmental conditions in a large storage area can be very difficult to achieve and monitoring the whole collection regularly for signs of pyrite decay may not be practicable. Therefore it would be useful for curators to know which specimens in their collection are most likely to suffer from pyrite decay.
Whilst there is a great deal of literature published on the mechanisms of pyrite oxidation and its treatment, there has been very little describing which sorts of specimens are prone to the process. A list of sites in the UK and Ireland from which problematic material is known is presented, with indications of what specimens from these sites are likely to suffer the most. This data has been crowd-sourced from curators, conservators, collectors and enthusiasts from around the UK and abroad.  It is not definitive but is a starting point and can be added to over time.
The most important specimens from sites identified on this list can be stored in appropriate environmental conditions and/or regularly monitored, and digitally imaged or physically replicated through casting or 3D printing to preserve a record in case the worst should happen in the future.

Two new species of the clypeasteroid Monostychia Laube, 1869, are described; M. merrimanensis sp. nov. from the East Gippsland region of
Victoria and M. glenelgensis sp. nov. from the Gambier Embayment of southwestern Victoria. M. etheridgei Tenison-Woods, 1877, from
northern Tasmania, which closely resembles M. merrimanensis sp. nov., is redescribed. A comparison is also made between M. elongata
Duncan, 1877, and M. glenelgensis, as both are present in the same strata. The new taxa differ from previously described Monostychia species in
size and shape and in the number of post-basicoronal plates on the oral surface. It is concluded that the use of oral plate counts and their
variation across a population may be diagnostically useful at species level, particularly those of the paired interambulacra and the unpaired
ambulacrum III.

Isolated conifer female reproductive structures are common fossil elements from Cenomanian (ca 99–94 Ma) charcoal- and resin-rich beds of the Tupuangi Formation, Chatham Islands, southwest Pacific Ocean. Recent findings have proposed that these are the oldest fossil evidence of serotiny, a highly successful fire-adaptive reproductive strategy common among tree species living in fire-prone areas today. Herein, we systematically describe the external morphological and anatomical features of these fossils, by employing a combination of manual extraction and neutron tomography techniques. We propose a new species of conifer, Protodammara reimatamoriori, and a re-examination of fossil material of the Protodammara type species facilitated an emendation of the genus. Protodammara shares numerous features with extant Cunninghamia, Taiwania, Athrotaxis, and several extinct taxa of Cupressaceae, and is interpreted as an extinct lineage of the early-divergent ‘taxodioid Cupressaceae’ stem group

Computed tomography is an increasingly popular technique for the non-destructive study of fossils. Whilst the science of X-ray computed tomography (CT) has greatly matured since its first fossil applications in the early 1980s, the applications and limitations of neutron tomography (NT) remain relatively unexplored in palaeontology. These highest resolution neutron tomographic scans in palaeontology to date were conducted on a specimen of Austrosequoia novae-zeelandiae (Ettingshausen) Mays and Cantrill recovered from mid-Cretaceous (Cenomanian; ~100–94 Ma) strata of the Chatham Islands, eastern Zealandia. Previously, the species has been identified with in situ fossil resin (amber); the new neutron tomographic analyses demonstrated an anomalously high neutron attenuation signal for fossil resin. The resulting data provided a strong contrast between, and distinct three-dimensional representations of the: 1) fossil resin; 2) coalified plant matter; and 3) sedimentary matrix. These data facilitated an anatomical model of endogenous resin bodies within the cone axis and bract-scale complexes. The types and distributions of resin bodies support a close alliance with Sequoia Endlicher (Cupressaceae), a group of conifers whose extant members are only found in the Northern Hemisphere. This study demonstrates the feasibility of NT as a means to differentiate chemically distinct organic compounds within fossils. Herein, we make specific recommendations regarding: 1) the suitability of fossil preservation styles for NT; 2) the conservation of organic specimens with hydrogenous consolidants and adhesives; and 3) the application of emerging methods (e.g., neutron phase contrast) for further improvements when imaging fine-detailed anatomical structures. These findings demonstrate that we are still far from reaching the conceptual limits of NT as a means of virtually extracting fossils, or imaging their internal anatomy even when embedded within a rock matrix.

The Tupuangi Flora of the Chatham Islands, New Zealand, reveals a south polar forest ecosystem, and important biogeographical links between eastern and western Gondwana. We employed neutron tomography (NT) to image fossil Cupressaceae seed cones from the Upper Cretaceous (Cenomanian) strata of the Tupuangi Formation. This technique facilitated the non-destructive ‘virtual extraction’ of three-dimensional, coalified specimens, whilst they were still embedded within a large volume of supporting silicate sedimentary rock. This study is the first reported application of NT in palaeobotanical taxonomy, and the combination of virtual and manual extraction techniques enabled a more complete treatment than would otherwise be possible if taxonomic data were limited to only one of these approaches. The seed cones were identified as Austrosequoia novae-zeelandiae (Ettingshausen) Mays & Cantrill comb. nov. In this case, NT data supplemented the compression fossil data by providing details such as the three-dimensional measurements of the gross morphology, and accurate estimations of bract-scale complex number. Furthermore, this technique appears to show promise in differentiating between organic compounds within an individual specimen. However, anatomical details and fine-scale morphology were indiscernible due to present limitations in spatial resolution. Austrosequoia novae-zeelandiae is interpreted as a stem group of Sequoioideae; it shares synapomorphic seed cone characters with extant sequoioids (e.g. Sequoia and Sequoiadendron), and plesiomorphic stomatal structures and leaf morphology. Abundant epiphyllous fungi (Plochmopeltinites sp.; Microthyriaceae) were also identified on the leaf cuticles of A. novae-zeelandiae. The high abundance of Austrosequoia in the Tupuangi Flora supports a cupressaceous floral province at south polar latitudes during the early Late Cretaceous. Furthermore, this stem group of Sequoioideae in eastern Gondwana during the early Late Cretaceous suggests an alternative, south-to-north dispersal route of sequoioids before the final continental separation of eastern and western Gondwana.