Quaternary history of deciduous forests of eastern North America and Europe

Abstract: The temperate deciduous forest of North America is more diverse than the deciduous forest of western Europe. This difference has traditionally been explained by greater survival in North America of deciduous species during the Quaternary. More recent investigations have shown, however, that late-Tertiary forests of Europe had already become dominated by conifers, with deciduous angiosperms a minor component. During the Quaternary, coniferous species and genera were lost from the European flora, leaving a few species and genera of angiosperms as the dominant trees. Cold, dry, continental climate during the glaciations caused the extinction of conifers; deciduous trees apparently survived these climatic conditions in pockets of favorable habitat in the eastern Mediterranean region. In eastern North America, in contrast, temperate deciduous forests are quite similar to the forests that were present in the late Tertiary. During the Quaternary, relatively few extinctions occurred, although deciduous angiosperms were displaced from the Appalachian mountains, surviving in small populations in the lower Mississippi valley or on the southern coastal plain. Coniferous forests dominated by spruce grew in the Great Plains, and forests dominated by pine grew on the southern part of the Atlantic coastal plain. At the opening of the Holocene, and presumably at the beginning of all the previous interglacials, tree distributions changed dramatically as temperate species rapidly extended their ranges northward. Range boundaries have continued to change throughout the Holocene, as expansions and contractions of range have occurred as the result of climatic change. Quaternary climatic history caused dramatic changes in the forests of both areas, indicating that modern species distributions can no longer be considered relicts of Tertiary distributions. Throughout the Quaternary, species ranges have changed in response to changes in regional climate; many forest communities are of recent origin, having received their present complements of tree species within the last 5,000 years. Forest communities in Eastern North America and in Western Europe as well have been invaded repeatedly during the Holocene by forest species expanding from refuges far to the south. Temperate deciduous forest grows over a wide area of eastern North America. The forest is rich in numbers of species, especially the mixed mesophytic forest communities of the southern Appalachians. These forests were traditionally compared with forests of the Tertiary Period (Reid, 1935; Braun, 1947, 1950; Campbell, 1982), when the so-called Arcto-Tertiary geoflora was supposed to have been widespread throughout the northern hemisphere (Chaney, 1944). Reid (1935) and Chaney (1944) believed that severe climate during the Quaternary Period eliminated the Arcto-Tertiary geoflora entirely from many regions, such as western North America, while in others, such as western Europe, extinctions eliminated all but a few species and genera. The modern deciduous forests were thus seen as remnants of an originally widespread, uniform vegetation. The geoflora concept has been challenged recently by Wolfe (1978, 1979) who argued that a uniform broad-leaved forest never existed. His analysis of the paleobotanical data shows that Tertiary floras were diverse, with evergreen gymnosperms such as Sequoia dominant in some regions, and evergreen angiosperms present elsewhere. He argued that a number of major climatic changes occurred during the Tertiary, especially during the Oligocene; these changes led to local changes in abundances of various components of the Tertiary flora. Thus changes of climate caused local adaptations rather than migrations of intact plant communities from one latitude to another as Chaney hypothesized (Wolfe, 1979). Before the end of the Tertiary Period, the forests of western United States were already dominated by conifers. A similar change had also occurred in Europe, where Pliocene floras contained many genera and species of conifers (Wolfe, 1979). Sequoia was the dominant tree in some regions (Traverse, 1982). Mixed coniferous-deciduous forest in Europe during the Pliocene is a new interpretation of forest history that stands in marked contrast to the traditional view. The traditional view held that deciduous forest persisted in Europe into the early Quaternary Period, when increasing se1 This work was supported by the National Science Foundation. 2 Department of Ecology and Behavioral Biology, University of Minnesota, Minneapolis, Minnesota 55455. ANN. MISSOURI BOT. GARD. 70:550-563. 1983. This content downloaded from 157.55.39.181 on Thu, 29 Sep 2016 05:51:40 UTC All use subject to http://about.jstor.org/terms 1983] DAVIS-QUATERNARY HISTORY 551 verity of climate caused extinctions of many angiosperm trees (Tralau, 1973; Campbell, 1982). In contrast, Wolfe emphasized that coniferous species and genera were the important losses from the European flora during the Quaternary. The Taxodiaceae, for example, once so important in the Black Sea region, were eliminated entirely (Traverse, 1982). The angiospermous genera that remain today represent differential survival of one component of what had been mixed coniferous-deciduous forest (Wolfe, 1979). Wolfe pointed out that Europe today has the type of climatic regime that elsewhere in the world supports mixed coniferous forest; the dominance of deciduous species in the region today is therefore anomalous. Eastern North America, in contrast, has a climatic regime typical of deciduous forest regions. Today it supports forests dominated by deciduous angiosperms, just as it did during the late Tertiary (Wolfe, 1979). The Quaternary pollen record adds a useful perspective to these differing views of the origin of the European deciduous forest and the relationship of deciduous forests in eastern North America and Europe. First, the Quaternary record shows that dramatic changes in the geographical ranges of forest species occurred during the Quaternary. We can no longer speak of Tertiary forest "remaining" in a region throughout the Quaternary, because many tree species were repeatedly displaced during the Quaternary from the geographical region where they now occur. For this reason, modern geographical ranges cannot be used to identify the locations of "relict" Tertiary forests. Second, the response of temperate forest trees to Quaternary climatic change was individualistic, supporting Wolfe's contention that Tertiaryfloras would not have migrated as units in response to climatic events. Third, the extinctions that occurred during the Quaternary, especially the differential extinctions of conifers and deciduous angiosperms document that the differential severity of Quaternary climate affectedforests differently in Europe and North America. These three factors contributed to the makeup of the modem temperate forest floras of North America and Europe. In considering how Quaternary climate changed Pliocene floras into modem floras, the two phases of Quaternary climate, glacial climates and interglacial climates, are important. The two phases appear to have had quite different effects. -Glacial phases, i.e., times when ice sheets were more extensive than at present, comprised about 90 percent of the time during the Quaternary period. During these long, cold intervals, temperate species survived in small populations that were susceptible to extinction. The severity of the climate, both in terms of average temperature, continentality, and drought; the extent of geographical displacement of plant species; the sizes of populations; and the community composition of forests in refuge areas; all had an effect on the probability of extinction for individual species. Interglacial intervals comprised a much smaller proportion (about 10 percent) of the Quaternary period. They were characterized by climates similar to those of today, which in Europe and eastern North America seem to bear a general resemblance to late-Tertiary climate. Each interglacial was short, lasting only 10,000 to 1 5,000 years, and began and ended with a sudden, major climatic change (Emiliani, 1972; Broecker & Van Donk, 1970). The interglacials, although favorable for survival and population expansion of temperate forest trees both in Europe and eastern North America, were times of vegetational instability. During interglacials the geographical distributions of temperate species shifted many hundreds of kilometers, and the composition of forest comunities changed rapidly. GEOLOGICAL EVIDENCE OF EVENTS DURING THE QUATERNARY PERIOD The exploration of the deep sea by geologists in the last twenty years has led to a new understanding of Quaternary events, revolutionizing our thinking about the time scale of glaciation. Many marine cores include sediment extending through the entire Quaternary Period. Previously, four major glaciations were recognized within the Quaternary. We now know that there were 18 or 20 glaciations during the last 2 million years, the time interval now assigned to the Quaternary. Each of these glacial cycles lasted about 100,000 years (Hays et al., 1969). Figure 1 shows oxygen-isotope paleoclimatic records for the last 800,000 years. The climatic events are well dated: the last interglacial (the earliest part of stage 5) started 125,000 years ago, lasted about 15,000 years, and ended with a sharp decline in temperature that initiated the last glaciation. Warm conditions returned, followed by a cold period, then a short warm interval. Seventy thousand years ago a long cold interval (stages 2-4) began, which culminated in the glacial maximum 18,000 to 20,000 years ago (Broecker & Van Donk, 1970). This content downloaded from 157.55.39.181 on Thu, 29 Sep 2016 05:51:40 UTC All use subject to http://about.jstor.org/terms 552 ANNALS OF THE MISSOURI BOTANICAL GARDEN [VOL. 70

deciduous forest
eastern north america
climatic change


Synapsid tracks with skin impressions illuminate the terrestrial tetrapod diversity in the earliest Permian of equatorial Pangea

Abstract: Lower Permian deposits of the Boskovice Basin in the Czech Republic have long been renowned for extraordinarily abundant specimens of discosauriscid seymouriamorphs, some of which showing exceptional preservation, including widespread soft tissues. The only other tetrapods from the strata are represented by rare temnospondyls. However, recent fieldwork in the Asselian (lowermost Permian) of the Boskovice Basin has yielded a diverse assemblage of tetrapod tracks, illuminating a hidden terrestrial tetrapod diversity. Here, we describe well-preserved isolated tracks, manus-pes couples, and a slab with trackways composed of approximately 20 tracks in at least four different directions belonging to early-diverging, or ‘pelycosaur-grade’, synapsids. The material originates from three localities situated within the Letovice and Padochov formations and is assignable to the ichnotaxon Dimetropus. The best-preserved specimen further shows rare skin impressions, which have not been observed from the hands or feet of early-diverging mammal-line amniotes before. The new material adds to the scarce record of synapsids from the Carboniferous/Permian transitional interval of equatorial Pangea. At the same time, it highlights the significance of the ichnological record of the Boskovice Basin which has long been neglected despite offering evidence for the presence of diverse faunal components that have not been reported from these basinal deposits before.

skin impression
terrestrial tetrapod diversity
pangea
temnospondyls
faunal component


Two-phase increase in the maximum size of life over 3.5 billion years reflects biological innovation and environmental opportunity

Abstract: The maximum size of organisms has increased enormously since the initial appearance of life >3.5 billion years ago (Gya), but the pattern and timing of this size increase is poorly known. Consequently, controls underlying the size spectrum of the global biota have been difficult to evaluate. Our period-level compilation of the largest known fossil organisms demonstrates that maximum size increased by 16 orders of magnitude since life first appeared in the fossil record. The great majority of the increase is accounted for by 2 discrete steps of approximately equal magnitude: the first in the middle of the Paleoproterozoic Era (≈1.9 Gya) and the second during the late Neoproterozoic and early Paleozoic eras (0.6–0.45 Gya). Each size step required a major innovation in organismal complexity—first the eukaryotic cell and later eukaryotic multicellularity. These size steps coincide with, or slightly postdate, increases in the concentration of atmospheric oxygen, suggesting latent evolutionary potential was realized soon after environmental limitations were removed.


Identifying Archaeological Bone via Non-Destructive ZooMS and the Materiality of Symbolic Expression: Examples from Iroquoian Bone Points

Abstract: Today, practical, functional and symbolic choices inform the selection of raw materials for worked objects. In cases where we can discern the origin of worked bone, tooth, ivory and antler objects in the past, we assume that similar choices are being made. However, morphological species identification of worked objects is often impossible due to the loss of identifying characteristics during manufacture. Here, we describe a novel non-destructive ZooMS (Zooarchaeology by Mass Spectrometry) method which was applied to bone points from Pre-Contact St. Lawrence Iroquoian village sites in southern Quebec, Canada. The traditional ZooMS technique requires destructive analysis of a sample, which can be problematic when dealing with artefacts. Here we instead extracted proteins from the plastic bags in which the points had been stored. ZooMS analysis revealed hitherto unexpected species, notably black bear (Ursus americanus) and human (Homo sapiens sapiens), used in point manufacture. These surprising results (confirmed through genomic sequencing) highlight the importance of advancing biomolecular research in artefact studies. Furthermore, they unexpectedly and exceptionally allow us to identify and explore the tangible, material traces of the symbolic relationship between bears and humans, central to past and present Iroquoian cosmology and mythology.

non-destructive zooms
bone point
protein


Caspary's fungi from Baltic amber: historic specimens and new evidence

Abstract: Amber is a valuable source of Mesozoic and Cenozoic fossil fungi. The earliest amber‐preserved fungi were described in the nineteenth and early twentieth centuries from Eocene Baltic amber. In 1907, Richard Klebs summarized the legacy of Robert Caspary based on his specimens, research notes and publications. This treatise contains descriptions and illustrations of 13 morphologies of fossil fungi which have not been investigated since. We managed to locate six of Caspary's amber specimens and imaged and re‐investigated the fossil fungi within. We provide amended descriptions of these six specimens, select new specimens from historic and recent collections which are probably conspecific with five fossils that appear to have been lost, and finally also describe and evaluate five newly found fossil fungi from Baltic amber. The fungi belong to the phylum Ascomycota (Subkingdom Dikarya). Only two of Caspary's fungi can be confidently assigned to modern genera, Metacapnodium (Metacapnodiaceae) and Calicium (Caliciaceae). The new combination Calicium succini (Caspary) Rikkinen & A. R. Schmidt is made. The fossils originally placed in Acremonium, Cetraria, Gonatobotrys, Ramularia, Stilbum and Torula cannot be assigned to these genera, and should not be used as minimum age constrains for the respective lineages.


Trophic Level Isotopic Enrichment of Carbon and Nitrogen in Bone Collagen: Case Studies from Recent and Ancient Terrestrial Ecosystems

Abstract: Prey-predator collagen enrichment values for carbon and nitrogen isotopic compositions are investigated. New enrichment values are given for the well-monitored ecosystem of Bialowieza primeval forest (Poland) for lynx and wolf. The impact of using different approximations in calculating such enrichment values is discussed. Several case studies of ancient vertebrate communities from Upper Palaeolithic sites in southwestern France are presented to check whether the enrichment values estimated for these past ecosystems are consistent with those measured in well-monitored modern ecosystems. The use of ranges of values rather than average ones is recommended, tentatively 0 to 2‰ for δ13C and 3 to 5‰ for δ15N. Copyright © 2003 John Wiley & Sons, Ltd.

carbon
bone collagen
case study
trophic level


Digital restoration of the pectoral girdles of two Early Cretaceous birds and implications for early-flight evolution

Abstract: The morphology of the pectoral girdle, the skeletal structure connecting the wing to the body, is a key determinant of flight capability, but in some respects is poorly known among stem birds. Here, the pectoral girdles of the Early Cretaceous birds Sapeornis and Piscivorenantiornis are reconstructed for the first time based on computed tomography and three-dimensional visualization, revealing key morphological details that are important for our understanding of early-flight evolution. Sapeornis exhibits a double articulation system (widely present in non-enantiornithine pennaraptoran theropods including crown birds), which involves, alongside the main scapula-coracoid joint, a small subsidiary joint, though variation exists with respect to the shape and size of the main and subsidiary articular contacts in non-enantiornithine pennaraptorans. This double articulation system contrasts with Piscivorenantiornis in which a spatially restricted scapula-coracoid joint is formed by a single set of opposing articular surfaces, a feature also present in other members of Enantiornithines, a major clade of stem birds known only from the Cretaceous. The unique single articulation system may reflect correspondingly unique flight behavior in enantiornithine birds, but this hypothesis requires further investigation from a functional perspective. Our renderings indicate that both Sapeornis and Piscivorenantiornis had a partially closed triosseal canal (a passage for muscle tendon that plays a key role in raising the wing), and our study suggests that this type of triosseal canal occurred in all known non-euornithine birds except Archaeopteryx, representing a transitional stage in flight apparatus evolution before the appearance of a fully closed bony triosseal canal as in modern birds. Our study reveals additional lineage-specific variations in pectoral girdle anatomy, as well as significant modification of the pectoral girdle along the line to crown birds. These modifications produced diverse pectoral girdle morphologies among Mesozoic birds, which allowed a commensurate range of capability levels and styles to emerge during the early evolution of flight.

pectoral girdle
early-flight evolution
sapeornis


The stapes of Lambdopsalis bulla (Multituberculata) and transformational analyses on some stapedial features in Mammaliaformes

Abstract: ABSTRACT The stapes of the Paleocene multituberculate Lambdopsalis bulla, recovered from a unique intra-vestibuli circumstance, is small and columelliform. It has a slim shaft, a slit-like stapedial foramen, a distinct head, and a well-developed, nearly circular footplate. With new evidence of the stapes from Lambdopsalis bulla and those reported recently from Sinoconodon, Haldanodon, and Pachygenelus, stapedial characters are analyzed in a selected group consisting of Placentalia, Marsu-pialia, Monotremata, Multituberculata, Morganucodontidae, Sinoconodon, Haldanodon, and the tritheledontid Pachygenelus. Stapedial characters discussed include relative size of the stapes, shape of the stapes, development of stapedial footplate, shape of the stapedial footplate, the stapedial foramen, position of the stapedial artery, and orientation of the stapes. Conclusions are: 1) the relative size of the stapes does not differentiate multituberculates from morganucodontids; 2) stapes are divided into three basic types...

stape
lambdopsalis bulla
multituberculata


Palaeontological Evidence for the Last Temporal Occurrence of the Ancient Western Amazonian River Outflow into the Caribbean

Abstract: Fossil catfishes from fluvio-lacustrine facies of late Miocene Urumaco, early Pliocene Castilletes and late Pliocene San Gregorio formations provide evidence of a hydrographic connection in what is today desert regions of northern Colombia and Venezuela. New discoveries and reevaluation of existing materials leads to the recognition of two new records of the pimelodid Brachyplatystoma cf. vaillantii, and of three distinct doradid taxa: Doraops sp., Rhinodoras sp., and an unidentified third form. The presence of fossil goliath long-whiskered catfishes and thorny catfishes are indicative of the persistence of a fluvial drainage system inflow into the South Caribbean during the Pliocene/Pleistocene boundary, complementary to the previous western Amazonian hydrographic system described from the Middle Miocene Villavieja Formation in central Colombia and Late Miocene Urumaco Formation in northwestern Venezuela. The Pliocene Castilletes and San Gregorio formations potentially represent the last lithostratigraphic units related with an ancient western Amazonian fish fauna and that drainage system in the Caribbean. Alternatively, it may preserve faunas from a smaller, peripheral river basin that was cut off earlier from the Amazon-Orinoco, today found in the Maracaibo basin and the Magdalena Rivers.

caribbean
hydrographic system
vertebrate fauna
turtle
south america


Mid-Tertiary paleoenvironments in Thailand: pollen evidence

Abstract: Abstract. Only few well-dated records document the evolution of Southeast Asian paleoenvironments during the Cenozoic. Here we analyse continental pollen assemblages from Late Oligocene and Miocene fossil sites of Thailand. In agreement with previous studies, palynoflora from the Oligocene suggests warm temperate forested habitats at 24–26 Ma, whereas Middle Miocene assemblages are made of thermophilous taxa. This change can be linked to the major climate reorganization that brought warmer and wetter conditions over Southeast Asia around 22 Ma. This study also provides the first submillional records from the Middle Miocene of Thailand. Thirteen samples of lignite layers from the sivaladapid-bearing Mae Moh site, dated between 13.3 and 13.1 Ma, and six samples from the hominoid-bearing Chiang Muan deposit, dated between 12.4 and 12.2 Ma, document oscillations between tropical woodlands and grasslands in northern Thailand. These pollen records likely reflect climate variations linked to insolation variations. Late Miocene palynological assemblages from Khorat, northeastern Thailand, document fluviolacustrine paleoenvironments alternatively covered by thermophilous trees and grasslands. These records show that both sivaladapids and early hominoids from Thailand have evolved in tropical environments with high variability in the vegetation cover.


A statistical study of Rhamphorhynchus from the Solnhofen Limestone of Germany: Year-classes of a single large species

Abstract: A statistical and morphological study of the pterosaur Rhamphorhynchus from the Solnhofen Limestone of Germany shows that specimens fall into discrete size-classes that are year-classes resulting from seasonal mortality or preservation of specimens. Taxonomic characters used in the past to separate species of Rhamphorhynchus are all related to size and ontogeny, and all specimens belong to a single species, R. muensteri. Thus, the collections of Rhamphorhynchus provide an unequaled record of the growth and development of a Jurassic rhamphorhynchoid pterosaur. Rhamphorhynchus did not have rapid determinate growth; the growth rate was comparable to that of extant crocodilians, and growth continued over the course of at least three years after individuals began to fly.

solnhofen limestone
germany
year-classe
pterosaur


New toothed Early Cretaceous ornithuromorph bird reveals intraclade diversity in pattern of tooth loss

Abstract: The earliest record of the Ornithuromorpha, which includes crown birds, is currently known from the Early Cretaceous Jehol Biota in north-eastern China. Here we describe a new ornithuromorph bird, Mengciusornis dentatus gen. et sp. nov., from the Jiufotang Formation of this biota. Mengciusornis preserves a suite of morphological features exclusively observed among ornithuromorphs in the sympatric taxon Schizooura, including a robust and ‘V’-shaped furcula with a short hypocleidium, and a humerus with a large, rectangular deltopectoral crest in which the distodorsal corner is distinctively developed into a sharp, angular point. The results of our phylogenetic analysis recover these two species together in a clade, positioned stemward within the Ornithuromorpha. Mengciusornis has toothed premaxillae, in stark contrast with the edentulous jaws of Schizooura, demonstrating that dentition varied considerably between some closely related species. Furthermore, all previously known Jehol ornithuromorphs with toothed premaxillae have an edentulous rostral portion of the element, suggesting that tooth loss in this clade proceeded from the rostral end caudally, whereas in Mengciusornis the premaxilla lacks this edentulous rostral tip although the maxilla and dentary are toothless, indicating that the pattern of tooth loss, not unexpectedly, varied between lineages of ornithuromorphs. This observation suggests a strong degree of plasticity in the developmental mechanisms regulating tooth and beak formation, which is supported by earlier evidence that indicates teeth have been lost multiple times within Aves and Dinosauria. Mengciusornis preserves a ventrally hooked scapular acromion that is convergently evolved in parallel with some enantiornithines and neornithines, providing further evidence of the homoplasy that characterizes avian evolution. http://zoobank.org/urn:lsid:zoobank.org:pub:311B34B9-1CBF-47A6-B821-650C04560137

ornithuromorph bird
tooth loss
jiufotang formation


Jaw Mechanics and Evolutionary Paleoecology of Megaherbivorous Dinosaurs from the Dinosaur Park Formation (Upper Campanian) of Alberta, Canada

Abstract:
ABSTRACT
 The question of what role differential jaw mechanics may have played in facilitating dietary niche partitioning among Late Cretaceous megaherbivorous dinosaurs from Laramidia is examined, using the fossil assemblage of the Dinosaur Park Formation as a test case. We use phylogenetic inference to reconstruct the mandibular adductor musculature of these animals, which we then apply to the construction of biomechanical lever models of the mandible to estimate relative bite forces. Our findings reveal predictably weak bite forces in ankylosaurs, and comparatively high bite forces in ceratopsids and hadrosaurids, both of which possessed a mechanical advantage that produced bite forces 2–3 times higher than those forces exerted by the adductor musculature. The impressive jaw mechanism shared by the last two taxa evolved in a stepwise fashion, independently in each lineage. There is tentative evidence to suggest that nodosaurids had more powerful bites than ankylosaurids, but the overall mechanical diversity among megaherbivores from the Dinosaur Park Formation is low, suggesting that differential jaw mechanics could have played only a subsidiary role in niche partitioning. Such mechanical conservatism may have may have been selected for, or it may simply reflect the limits imposed by evolutionary constraints. Regardless, mechanical disparity patterns remained stable throughout the ∼1.5 Ma evolution of the Dinosaur Park Formation megaherbivore chronofauna.

megaherbivorous dinosaur
dinosaur park formation
jaw mechanism


Human mummified brain from a medieval tomb with lime‐soil mixture barrier of the Joseon Dynasty, Korea

Abstract: Although all of the Korean medieval mummies found up to the present time have shown relatively well-preserved brains, relevant biomedical information has been difficult to acquire owing to the obstacles to obtaining permission to conduct invasive investigations. However, recently we were able to secure permission to investigate, through various forms of examination including dissection, a well-preserved brain found in a lime-soil mixture barrier (LSMB) tomb in Yongin, Korea, because the remains found within the tomb were mostly skeletal. As in the cases of mummified brains from tombs found in other countries, the current Yongin case showed well-preserved grey and white matter within well demarcated brain lobes, on which sulci and gyri could be identified. On histological examination, we found that the remaining brain tissue was composed mainly of lipids, which seems to correspond to the preserved myelin sheath. The present paper is the first report on the general preservation status of a mummified brain found in Korea. Moreover, because mummified brains are found quite frequently in LSMB medieval tombs, this study could provide a good basis upon which further such palaeo-neuropathological studies can be progressed. Copyright © 2008 John Wiley & Sons, Ltd.


Trilobite malformations and the fossil record of behavioral asymmetry

Abstract: Malformations of trilobites are classified as healed injuries, teratological conditions, and pathological conditions. An improved method of recognizing such malformations combines information about the conditions under which cell injury can occur, the processes by which animal tissues react to injury, and trilobite morphology. Study of healed injuries of polymeroid trilobites shows that injuries attributed to sublethal predation tend to be most commonly preserved on the pleural lobes, the posterior half of the body, and the right side. Statistically significant differences in the number of predation scars between the right and left sides is interpreted as evidence of right-left behavioral asymmetry in some predators of trilobites or the trilobites themselves. Asymmetrical, or lateralized, behavior in present-day animals is one manifestation of handedness, and is usually related to a functional lateralization of the nervous system. Evidence of behavioral lateralization in some Paleozoic predators or prey suggests that those organisms also possessed lateralized nervous systems. Right-left differences in preserved predation scars on trilobites date from the Early Cambrian (Olenellus Zone), and are the oldest known evidence of behavioral asymmetry in the fossil record. Other examples of structural or behavioral asymmetry from the fossil record of animals are cited. Lateralization is recognized in representatives of the Arthropoda, Annelida, Bryozoa, Echinodermata, Cnidaria, Mollusca, Chordata, and Conodonta, and in trace fossils.

malformation
behavioral asymmetry
injury
trilobite morphology
predator


Genomic evidence reveals a radiation of placental mammals uninterrupted by the KPg boundary

Abstract: Significance We produced a genome-scale dataset from representatives of all placental mammal orders to infer diversification timing relative to the Cretaceous–Paleogene (KPg) boundary. Our sensitivity analyses show that divergence time estimates within placentals are considerably biased by the specific way in which a given dataset is processed. We examined the performance of various dating approaches using a comprehensive scheme of likelihood analyses and computational simulations, allowing us to identify the optimal molecular clock parameters, gene sets, and gene partitioning schemes for reliable dating. Based on the optimal methodology, we present a hypothesis of mammalian divergence timing that is more consistent with the fossil record than previous molecular clock reconstructions, suggesting that placental mammals underwent a continuous radiation across the KPg boundary. The timing of the diversification of placental mammals relative to the Cretaceous–Paleogene (KPg) boundary mass extinction remains highly controversial. In particular, there have been seemingly irreconcilable differences in the dating of the early placental radiation not only between fossil-based and molecular datasets but also among molecular datasets. To help resolve this discrepancy, we performed genome-scale analyses using 4,388 loci from 90 taxa, including representatives of all extant placental orders and transcriptome data from flying lemurs (Dermoptera) and pangolins (Pholidota). Depending on the gene partitioning scheme, molecular clock model, and genic deviation from molecular clock assumptions, extensive sensitivity analyses recovered widely varying diversification scenarios for placental mammals from a given gene set, ranging from a deep Cretaceous origin and diversification to a scenario spanning the KPg boundary, suggesting that the use of suboptimal molecular clock markers and methodologies is a major cause of controversies regarding placental diversification timing. We demonstrate that reconciliation between molecular and paleontological estimates of placental divergence times can be achieved using the appropriate clock model and gene partitioning scheme while accounting for the degree to which individual genes violate molecular clock assumptions. A birth-death-shift analysis suggests that placental mammals underwent a continuous radiation across the KPg boundary without apparent interruption by the mass extinction, paralleling a genus-level radiation of multituberculates and ecomorphological diversification of both multituberculates and therians. These findings suggest that the KPg catastrophe evidently played a limited role in placental diversification, which, instead, was likely a delayed response to the slightly earlier radiation of angiosperms.

placental mammal
kpg boundary
diversification


Spatial distribution of climatic conditions from the Middle Eocene to Late Miocene based on palynoflora in Central, Eastern and Western Anatolia

Abstract: The continental climatic evolution of Anatolia has been reconstructed quantitatively for the last 45 million years using the coexistence approach. Although there were some regional effects, the Anatolian Cenozoic continental climate record correlated with the European climatic condition and the global oxygen isotope record from marine environments. From middle Eocene to late Miocene, continental warming in Anatolia was pronounced for inferred winter temperature and mean annual temperature as in Europe. Generally, the palaeoclimatic property of Anatolia resembles the European climatic changing and marine temperature changing based on the oxygen isotope record; however, climatic values of the terrestrial area in Anatolia are higher from Lutetian to Aquitanian and these values are lower than European values from Aquitanian to Tortonian. Correspondingly, Cenozoic climatic cooling in Anatolia is directly associated with an increase of seasonality, palaeogeographic position and terrestrial condition. Furthermore, mean annual precipitation values of Anatolia remained relatively stable during the Eocene–Oligocene; however, these values indicated changing throughout middle–late Miocene. Moreover, in this study, decline of abundance and variables for the mangrove and back mangrove palaeocommunities during the last 45 million years is recorded because of the decreasing of humidity, temperature and increasing of terrestrial condition.

climatic condition
middle eocene
anatolia


Deer in an arid habitat: dental microwear textures track feeding adaptability

Abstract: Teeth constitute a bridge between an organism and its environment. Dental wear is a good proxy for (paleo) ecologists to better comprehend the ecology and habitat of modern and extinct species. In this study, we showed Dental Microwear Texture Analysis to be a useful tool, integrating not only specific plant selection but also dietary quality and digestibility in order to understand resource use. Resource-partitioning, seasonal and sexual variations in the diet of two deer species on a Spanish game estate are explored here through Dental Microwear Texture Analysis. This Mediterranean area is on the fringes of the average European environments in terms of constraints and diet for extant red and fallow deer, resulting in an opportunity to understand their ability to live in harsh conditions and the feeding strategies they developed. These two taxa already experienced harsh living conditions during the Pleistocene. Dental microwear texture shows both deer feeding differently on the herbaceous layer in a context where it is the main resource consumed annually. These differences are linked to body mass. With its smaller incisor arcade, Dama dama is able to be more selective, hence focusing on less fibrous parts of forages. Cervus elaphus is more plastic, with dietary variations corresponding to seasonal plant availability and the physiological requirements of stags and does. In general, C. elaphus consumes a more fibrous and less digestible vegetable material than D. dama . This study brings light on the feeding behavior of the two game species under constraint conditions. The results of this study are discussed in terms of realized vs potential ecological niche.


A new trackway possibly made by a trotting theropod at the Las Hoyas fossil site (Early Cretaceous, Cuenca Province, Spain): Identification, bio-dynamics and palaeoenvironmental implications

Abstract: Dinosaur footprints have recently been identified at the Las Hoyas fossil site, renewing interest in its trace fossils as aids in the interpretation of the area's palaeoenvironment and palaeocommunity. The varied tetrapod print morphologies found seem to have been influenced by the contemporaneous presence of microbial mats. This paper updates the information on tetrapod traces at the site and describes a new dinosaur trackway containing four tridactyl footprints. Although the trackway is not particularly well-preserved, the morphology of the toe marks, the heel surface, and the general morphology of the prints strongly suggest they were produced by a theropod dinosaur of medium size. Further, the ratio between the stride length and the deduced hip height suggest the trackmaker was trotting. Interestingly, the footprints are very similar in size to the pes of Concavenator, a carcharodontosaurid dinosaur known from skeletal material at the same locality. This new ichnological evidence reveals tetrapod prints to be more abundant toward the top of the siteʼs stratigraphic succession. This suggests that, over time, the ecosystem evolved toward more frequent dry periods the dinosaurs present became able to walk in areas with shallow water and big dinosaurs walked across the ponding zone of Las Hoyas. J.J. Moratalla. Instituto Geológico y Minero de España (Igme), Museo Geominero, Ríos Rosas 23, 28003 Madrid, Spain. j.moratalla@igme.es J. Marugán-Lobón. Unidad de Paleontología, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain and Dinosaur Institute, Natural History Museum of Los Angeles County, Los Angeles, CA, USA. jesus.marugan@uam.es H. Martín-Abad. Jurassica Museum, Route de Fontenais 21, 2900 Porrentruy, Switzerland. hugo.martin.abad@gmail.com and Department of Geosciences, University of Fribourg, Chemin du Musée 6, 1700 Fribourg, Switzerland E. Cuesta. Unidad de Paleontología, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain. elena.cuesta@uam.es Moratalla, J.J., Marugán-Lobón, J., Martín-Abad, H., Cuesta, E. and Buscalioni, A.D. 2017. A new trackway possibly made by a trotting theropod at the Las Hoyas fossil site (Early Cretaceous, Cuenca Province, Spain): Identification, bio-dynamics, and palaeoenvironmental implications. Palaeontologia Electronica 20.3.59A: 1-14. https://doi.org/10.26879/770 palaeo-electronica.org/content/2017/2073-theropod-trackway-at-las-hoyas Copyright: November 2017 Palaeontological Association. This is an open access article distributed under the terms of Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0), which permits users to copy and redistribute the material in any medium or format, provided it is not used for commercial purposes and the original author and source are credited, with indications if any changes are made. creativecommons.org/licenses/by-nc-sa/4.0/ MORATALLA ET AL.: THEROPOD TRACKWAY AT LAS HOYAS A.D. Buscalioni. Unidad de Paleontología, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain. angela.delgado@uam.es.

trotting theropod
bio-dynamic
palaeoenvironmental implication
succession


Grades and clades in hornless ruminant evolution: the reality of the Gelocidae and the systematic position of Lophiomeryx and Bachitherium

Abstract: ABSTRACT The phylogenetic relationships of hornless ruminants are reassessed in light of consideration of the systematic position of the genera Lophiomeryx (previously assigned to the Gelocidae), and Bachitherium (previously assigned to the Leptomerycidae or Hypertragulidae), and the reality of the Gelocidae as a cladistically valid taxon is questioned. It is concluded that Lophiomeryx should be placed in its own family, the Lophiomeryicidae (along with the genera Cryptomeryx and Iberomeryx, previously assigned to the Tragulidae), and that the family forms the sister group to the Pecora. Bachitherium is also best placed in its own family, the Bachitheriidae, forming the sister group to the Pecora plus the Lophiomeryicidae. The Gelocidae cannot be united by any unique character, and are best considered a polyphyletic assemblage of primitive pecorans, from among which the higher pecoran families may be derived.

systematic position
lophiomeryx
bachitherium


A Levallois point embedded in the vertebra of a wild ass (Equus africanus): hafting, projectiles and Mousterian hunting weapons

Abstract: The hunting methods of the Neanderthals are rarely evident in detail in the archaeological record. Here, the rare and important discovery of a fragment of broken Levallois point, embedded in the neck-bones of a wild ass, provokes plenty of discussion of the methods of hafting and killing game in the Middle Palaeolithic of Syria.


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

Abstract: 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.

soft‐tissue phosphatization
musculature
tissue


High frequencies of theropod bite marks provide evidence for feeding, scavenging, and possible cannibalism in a stressed Late Jurassic ecosystem

Abstract: Bite marks provide direct evidence for trophic interactions and competition in the fossil record. However, variations in paleoecological dynamics, such as trophic relationships, feeding behavior, and food availability, govern the frequency of these traces. Theropod bite marks are particularly rare, suggesting that members of this clade might not often focus on bone as a resource, instead preferentially targeting softer tissues. Here, we present an unusually large sample of theropod bite marks from the Upper Jurassic Mygatt-Moore Quarry (MMQ). We surveyed 2,368 vertebrate fossils from MMQ in this analysis, with 684 specimens (28.885% of the sample) preserving at least one theropod bite mark. This is substantially higher than in other dinosaur-dominated assemblages, including contemporaneous localities from the Morrison Formation. Observed bite marks include punctures, scores, furrows, pits, and striations. Striated marks are particularly useful, diagnostic traces generated by the denticles of ziphodont teeth, because the spacing of these features can be used to provide minimum estimates of trace maker size. In the MMQ assemblage, most of the striations are consistent with denticles of the two largest predators known from the site: Allosaurus and Ceratosaurus. One of the bite marks suggests that a substantially larger theropod was possibly present at the site and are consistent with large theropods known from other Morrison Formation assemblages (either an unusually large Allosaurus or a separate, large-bodied taxon such as Saurophaganax or Torvosaurus). The distribution of the bite marks on skeletal elements, particularly those found on other theropods, suggest that they potentially preserve evidence of scavenging, rather than active predation. Given the relative abundances of the MMQ carnivores, partnered with the size-estimates based on the striated bite marks, the feeding trace assemblage likely preserves the first evidence of cannibalism in Allosaurus.

frequency
theropod bite mark
cannibalism
morrison formation


Geometric morphometric assessment of Guanshan trilobites (Yunnan Province, China) reveals a limited diversity of palaeolenid taxa

Abstract: The Guanshan Biota is a typical Burgess Shale-type Cambrian-aged Lagerstätte with diverse trilobites. As such, the taxonomy of trilobites from the Guanshan Biota, especially the palaeolenid group, has been the focus of research over the last decade. To develop this research, we present a geometric morphometric analysis of cranidial shape in 60 specimens from three sections of the Guanshan Biota from the Wulongqing Formation (Cambrian Series 2, Stage 4), Yunnan Province, South China. We show that cranidia of Megapalaeolenus deprati and Palaeolenus douvillei occupy distinct regions of morphospaces and that P. douvillei and P. “lantenoisi” occupy the same region of morphospace. Combined with qualitative observation on the thorax, P. “lantenoisi” is here considered a junior synonym of P. douvillei. Megapalaeolenus deprati is still considered valid and is distinguished from P. douvillei by its rounded glabella, longer palpebral lobes, shorter ocular ridges, and more developed posterolateral projections. Its pleural spines are more curved, and pleural lobes are markedly wider than P. douvillei. These results highlight that the supposed diversity of palaeolenid taxa in lower Cambrian deposits need reconsideration, potentially using similar morphometric methods. Wenyu Zhao. Early Life Institute, State Key Laboratory of Continental Dynamics, Department of Geology, Northwest University, Xi’an, Shaanxi, China. zhaowenyunwu@126.com Jianni Liu. Early Life Institute, State Key Laboratory of Continental Dynamics, Department of Geology, Northwest University, Xi’an, Shaanxi, China. liujianni@126.com Russell D.C. Bicknell. Palaeoscience Research Centre, School of Environmental and Rural Science, University of New England, Armidale, New South Wales, Australia, 2351. rdcbicknell@gmail.com

trilobite
yunnan province
china
palaeolenid taxa


Coccolithophore calcification response to past ocean acidification and climate change

Abstract: Anthropogenic carbon dioxide emissions are forcing rapid ocean chemistry changes and causing ocean acidification (OA), which is of particular significance for calcifying organisms, including planktonic coccolithophores. Detailed analysis of coccolithophore skeletons enables comparison of calcite production in modern and fossil cells in order to investigate biomineralization response of ancient coccolithophores to climate change. Here we show that the two dominant coccolithophore taxa across the Paleocene–Eocene Thermal Maximum (PETM) OA global warming event (~56 million years ago) exhibited morphological response to environmental change and both showed reduced calcification rates. However, only Coccolithus pelagicus exhibits a transient thinning of coccoliths, immediately before the PETM, that may have been OA-induced. Changing coccolith thickness may affect calcite production more significantly in the dominant modern species Emiliania huxleyi, but, overall, these PETM records indicate that the environmental factors that govern taxonomic composition and growth rate will most strongly influence coccolithophore calcification response to anthropogenic change.

calcification response
ocean acidification
climate change
coccolithus pelagicus


Understanding Eocene primate palaeobiology using a comprehensive analysis of living primate ecology, biology and behaviour

Abstract: The comparative method is central to interpretations of Eocene primate palaeobiology. This method rests upon a thorough study of analogous living forms. With a rapidly increasing knowledge of such forms, most notably the Malagasy lemurs, our ability to advance the study of Eocene primate ecology, biology and behaviour far exceeds that of even just a few years ago. Here we present such a comparison. Based on our data collected from both living lemurs and extant lemur skeletal specimens, we are able to make a number of comparisons that provide insight into middle Eocene primate ecology and palaeobiology. At the Beza Mahafaly Special Reserve, Madagascar, omnivorous living ring-tailed lemurs that feed on large, hard and tough fruits display a pattern of frequent post-canine tooth wear laterality (62 %) when compared to sympatric, folivorous Verreaux's sifaka (4 %). Our results indicate that Notharctus does not display a high frequency of tooth wear laterality (7 %), indicating folivory without processing large, hard fruits with its postcanines. Our data on Notharctus tooth wear also indicate, similar to living ring-tailed lemurs at Beza Mahafaly, that numerous individuals (21 %) survived long enough to experience heavy tooth wear, contrary to the assumption that heavy tooth wear leads to the rapid death of the individual. Finally, our data on trauma and injury from a living lemur population suggest that the reported wrist injury in Darwinius masillae (i.e. "Ida") did not necessarily lead to her death, as numerous ring-tailed lemurs at Beza Mahafaly survive with similar or even more traumatic injuries and maintain the ability to climb. Thus, our data from living primates provide a broad comparative framework for interpreting the ecology, biology and behaviour of Eocene forms.

eocene primate palaeobiology
behaviour
lemur population


Reevaluating the timing of Neanderthal disappearance in Northwest Europe

Abstract: Significance Understanding when Neanderthals disappeared is a hotly debated topic. When radiocarbon dating placed the Spy Neanderthals amongst the latest surviving in Northwest Europe, questions were raised regarding the reliability of the dates. Using a procedure more efficient in removing contamination and ancient genomic analysis, we show that previous dates produced on Neanderthal specimens from Spy are too young by up to 10,000 y. Our direct radiocarbon dates on the Neanderthals from Spy and those from Engis and Fonds-de-Forêt show a reduction of the uncertainty for the time window corresponding to Neanderthal disappearance in Northwest Europe. This population disappeared at 44,200 to 40,600 cal B.P. (at 95.4% probability). This is also earlier than previous suggestions based on dates on bulk collagen. Elucidating when Neanderthal populations disappeared from Eurasia is a key question in paleoanthropology, and Belgium is one of the key regions for studying the Middle to Upper Paleolithic transition. Previous radiocarbon dating placed the Spy Neanderthals among the latest surviving Neanderthals in Northwest Europe with reported dates as young as 23,880 ± 240 B.P. (OxA-8912). Questions were raised, however, regarding the reliability of these dates. Soil contamination and carbon-based conservation products are known to cause problems during the radiocarbon dating of bulk collagen samples. Employing a compound-specific approach that is today the most efficient in removing contamination and ancient genomic analysis, we demonstrate here that previous dates produced on Neanderthal specimens from Spy were inaccurately young by up to 10,000 y due to the presence of unremoved contamination. Our compound-specific radiocarbon dates on the Neanderthals from Spy and those from Engis and Fonds-de-Forêt demonstrate that they disappeared from Northwest Europe at 44,200 to 40,600 cal B.P. (at 95.4% probability), much earlier than previously suggested. Our data contribute significantly to refining models for Neanderthal disappearance in Europe and, more broadly, show that chronometric models regarding the appearance or disappearance of animal or hominin groups should be based only on radiocarbon dates obtained using robust pretreatment methods.

neanderthal disappearance
northwest europe
procedure


Homology problems in cephalopod morphology: deceptive (dis)similarities between different types of 'caecum'

Abstract: Homoplasy is a common phenomenon in the evolution of the Cephalopoda. Many homology problems accordingly light up phylogenetic debates. The initial segment of the siphuncle, the so-called 'caecum', is one of these characters difficult to be unambiguously evaluated. Although rarely discussed, the caecum of the endocochleate decabrachian Spirula is traditionally seen as a plesiomorphy directly inherited from its ectocochleate ancestors. However, the Spirula caecum must be-according to recent phylogenetic analyses-derived from a substructure of the belemnoid protoconch. Here, I review the morphology of different types of ectocochleate and endocochleate protoconchs. Detailed comparisons show that belemnoid protoconchs are structurally closer to the bactritoid/ammonoid protoconch than to the spiruloid protoconch. The most striking difference between the caecum of Spirula and bactritoids or ammonoids concerns its ultrastructure, which is lamello-fibrillar nacre (Spirula nacre or nacre type II) in the former and organic in the latter. The Spirula caecum is consequently equivalent to the first septum, while in bactritoids/ammonoids, the caecum is a separate structure independent of the proseptum. To conclude, the spiruloid protoconch (including caecum) has been derived either from a belemnitid or diplobelid protoconch. Similarities between the bactritoid/ammonoid and spiruloid caecum are superficial and only concern its shape.

morphology
caecum
initial segment
homology problem


Biological fractionation of silicon isotopes in Southern Ocean surface waters

Abstract: The fractionation of silicon isotopes by diatoms during silicification (i.e., opaline cell wall formation) provides a new tool for paleoceanographic studies of the silicon cycle. Here we examine the natural variations of the 30Si:28Si ratio in silicic acid (Si(OH)4) and biogenic silica (bSiO2) in surface waters of the Antarctic Circumpolar Current (ACC) along 170°W. The results provide direct evidence of biologically mediated fractionation of silicon isotopes, with an enrichment factor (ɛ) of between −1.1 and −1.9‰, depending on the model employed. Comparison of the mass flux of bSiO2 captured in sediment traps deployed in the study area with the silicon isotopic composition of that material establishes a direct linkage between diatom dynamics in surface waters and the isotopic signature of exported particles. We calculated Si(OH)4:NO3− utilization ratios from variations in silicon and nitrogen isotopic ratios in surface waters and sediment traps that agree well with direct observations of 4:1 in this region. This work supports the use of variations in silicon isotopes in sedimentary opal as a proxy for relative Si(OH)4 utilization in surface waters.

fractionation
silicon isotope
surface water


A Skull of Plesiaceratherium gracile (Rhinocerotidae, Perissodactyla) from a New Lower Miocene Locality in Shandong Province, China, and the Phylogenetic Position of Plesiaceratherium

Abstract:
ABSTRACT
 A well-preserved fossil skull from a new locality in Jijiazhuang, Changle County, Shandong Province, China, is attributable to Plesiaceratherium gracile. Other rhinoceroses from the nearby Shanwang Basin of Linqu County, Shandong, formerly described as Aceratherium sp. and Plesiaceratherium shanwangensis are also referable to P. gracile. The new skull demonstrates the presence in P. gracile of the following characters: continuous labial cingula on lower cheek teeth; skull roof with nearly flat profile; and external auditory pseudomeatus ventrally closed, proceeding dorsocaudally in a shallow groove. Comparison of Plesiaceratherium with Brachypotherium pugnator Matsumoto, 1921, suggests that referral of the latter to Plesiaceratherium should be reconsidered. A phylogenetic analysis based on 314 characters scored for 39 terminal taxa places Plesiaceratherium mirallesi in a basal position within Rhinocerotidae, and recovers other species of Plesiaceratherium as a clade that is well separated from B. pugnator and is sister to the [Subchilotherium [Acerorhinus [Shansirhinus, B. pugnator [Chilotherium]]]] grouping. Based on this result and a reevaluation of the anatomy of ‘P.’ mirallesi, we propose that the genus Dromoceratherium should be revived to accommodate this species as D. mirallesi. The occurrence of P. gracile at Jijiazhuang indicates that the fossiliferous diatomaceous shales of this locality were deposited during the lower Miocene.

skull
plesiaceratherium gracile
rhinocerotidae


First Record and a New Species of Seriema (Aves: Ralliformes: Cariamidae) from Santacrucian (Early-Middle Miocene) Beds of Patagonia

Abstract: Living seriemas (Ralliformes, Cariamidae) are long-legged cursorial birds that comprise only two very closely related, and perhaps congeneric, species (Gonzaga, 1996): Cariama cristata and Chunga burmeisteri. They are endemic to South America and may represent surviving Neotropical relicts of an early ralli form radiation within the suborder Cariamae. Phorusrhacids, idiornithids, and bathornithids are also extinct components of ralliforms, a large terrestrial stock of predator or scavenger birds, which were abundant during the Tertiary of South and North America, and Europe (Mourer Chauvire, 1981, 1983; Alvarenga and H?fling, 2003). The phylogenetic relation ships and paleobiogeographic history of phorusrhacids, idior nithids, and bathornithids are still far from being resolved. Tertiary fossils of the cariamid subtaxon Cariaminae are scarce and restricted to the questionable record of Riacama caliginea Ameghino 1899 from the late Oligocene (Deseadan age) of Santa Cruz Province (see Brodkorb, 1967; Tonni, 1980; Tambussi and Noriega, 1996; Agnolin, 2004), and the early-middle Pliocene (Montehermosan age) record of Chunga incerta Tonni (1974) from Buenos Aires Province, both in Argentina. In this contribution we present new remains of seriemas re covered in 2005 by a joint expedition of the Museo de La Plata, Argentina, and Duke University, USA. They come from the middle levels of the Santa Cruz Formation (Upper-middle Mio cene) along the Atlantic coast of southernmost continental Pata gonia, Argentina, between the Coyle and Gallegos rivers. These localities are situated at about 52 degrees South latitude, about 100 km north to the Magallanes Strait (Fig. 1). In the mentioned area, the Santa Cruz Formation bears a terrestrial vertebrate fauna exceptional in its richness with over 70 species recorded in about 30 fossiliferous levels (Tauber, 1997a, Tauber 1997b; Tauber et al., 2004) that represents the richest assemblage of pre-Pleistocene mammalian skulls and ar ticulated skeletons known in the continent (Hatcher, 1903). A description of the localities and horizons that produced the fossils reported here is provided in the following section. Although still far fewer than mammals, these localities have provided quite a number of bird remains. Many of them were described and beautifully figured in the extensive Reports of the Princeton University Expeditions to Patagonia (Sinclair and Farr, 1932). They include Phorusrhacos longissimus Ameghino 1887, Brontornis burmeisteri Moreno and Mercerat 1891, Patagornis marshi Moreno and Mercerat 1891, Psilopterus bachmanni (Moreno and Mercerat 1891), and Psilopterus lemoinei (Moreno and Mercerat 1891), among the Phorusrhacids. Other bird taxa recorded at the Santa Cruz Formation include Tinamidae (Chiappe, 1991), Rheidae (Opisthodactylus patagonicus Ame ghino 1891), Pelecanidae (Liptornis hesternus Ameghino 1895), Plataleidae (Protibis cnemialis Ameghino 1891), Anatidae (Eone ornis australis Ameghino 1895; Eutelornis patagonicus Ameghino 1895), Aramidae (Anisolornis excavatus Ameghino 1891), and Falconiformes (Badiostes patagonicus Ameghino 1895; Thegornis debilis Ameghino 1895 and T. musculosus Ameghino 1899). Most of these taxa were erected on the basis of very fragmentary and eroded specimens, together with brief and poorly illustrated descriptions, that make difficult to assess their validity (Olson, 1981, 1985; Tonni, 1980; Tambussi and Noriega, 1996). Some of them have been recently revised (Alvarenga and H?fling, 2003; Agnolin, 2004, 2006, 2007).


I/Ca evidence for upper ocean deoxygenation during the PETM

Abstract: Anthropogenic global warming affects marine ecosystems in complex ways, and declining ocean oxygenation is a growing concern. Forecasting the geographical and bathymetric extent, rate, and intensity of future deoxygenation and its effects on oceanic biota, however, remains highly challenging because of the complex feedbacks in the Earth-ocean biota system. Information on past global warming events such as the Paleocene-Eocene Thermal Maximum (PETM, ~55.5 Ma), a potential analog for present and future global warming, may help in such forecasting. Documenting past ocean deoxygenation, however, is hampered by the lack of sensitive proxies for past oceanic oxygen levels throughout the water column. As yet no evidence has been presented for pervasive deoxygenation in the upper water column through expansion of oxygen minimum zones (OMZs). We apply a novel proxy for paleoredox conditions, the iodine to calcium ratio (I/Ca) in bulk coarse fraction sediment and planktonic foraminiferal tests from pelagic sites in different oceans, and compared our reconstruction with modeled oxygen levels. The reconstructed iodate gradients indicate that deoxygenation occurred in the upper water column in the Atlantic, Indian Oceans, and possibly the Pacific Ocean, as well during the PETM, due to vertical and potentially lateral expansion of OMZs.

ocean deoxygenation
petm
oxygen minimum zone


The Origin and Early Evolution of Sauria: Reassessing the Permian Saurian Fossil Record and the Timing of the Crocodile-Lizard Divergence

Abstract: Sauria is the crown-group of Diapsida and is subdivided into Lepidosauromorpha and Archosauromorpha, comprising a high percentage of the diversity of living and fossil tetrapods. The split between lepidosauromorphs and archosauromorphs (the crocodile-lizard, or bird-lizard, divergence) is considered one of the key calibration points for molecular analyses of tetrapod phylogeny. Saurians have a very rich Mesozoic and Cenozoic fossil record, but their late Paleozoic (Permian) record is problematic. Several Permian specimens have been referred to Sauria, but the phylogenetic affinity of some of these records remains questionable. We reexamine and review all of these specimens here, providing new data on early saurian evolution including osteohistology, and present a new morphological phylogenetic dataset. We support previous studies that find that no valid Permian record for Lepidosauromorpha, and we also reject some of the previous referrals of Permian specimens to Archosauromorpha. The most informative Permian archosauromorph is Protorosaurus speneri from the middle Late Permian of Western Europe. A historically problematic specimen from the Late Permian of Tanzania is redescribed and reidentified as a new genus and species of basal archosauromorph: Aenigmastropheus parringtoni. The supposed protorosaur Eorasaurus olsoni from the Late Permian of Russia is recovered among Archosauriformes and may be the oldest known member of the group but the phylogenetic support for this position is low. The assignment of Archosaurus rossicus from the latest Permian of Russia to the archosauromorph clade Proterosuchidae is supported. Our revision suggests a minimum fossil calibration date for the crocodile-lizard split of 254.7 Ma. The occurrences of basal archosauromorphs in the northern (30°N) and southern (55°S) parts of Pangea imply a wider paleobiogeographic distribution for the group during the Late Permian than previously appreciated. Early archosauromorph growth strategies appear to be more diverse than previously suggested based on new data on the osteohistology of Aenigmastropheus.

sauria divergence archosauromorph paleozoic


Dasyclads, cyclocrinitids and receptaculitids: comparative morphology and paleoecology

Abstract: The cyclocrinitids are an extinct tribe of dasycladacean green algae. They were anatomically very similar to certain Recent dasyclads, even at early growth stages. The morphology and preservation of cyclocrinitids strongly suggest that they had a siphonous cellular organization with extracellular, aragonitic calcification; these features are characteristic of living dasyclads. The light surficial calcification of cyclocrinitids and other dasyclads had important paleoecological effects. It restricted them to low-energy waters, as it provided relatively little structural support. It also confined them to warm, tropical waters; they are good paleoequatorial indicators. The decline of these algae during the late Ordovician and early Silurian may therefore reflect the simultaneous cooling and glaciation. Receptaculitids are entirely unrelated organisms. Their meroms have several distinctive features; they are not homologous to the lateral branches of cyclocrinitids or dasyclads. Receptaculitid calcification was extensive and their thalli were apparently quite sturdy; they often occurred in reefs. Receptaculitids also lived in high-latitude, cold-water environments. Thus, they were ecologically unlike any calcareous green algae, and cannot be used as paleoequatorial indicators. Receptaculitids remain problematical, although the arrangement of meroms suggests plant affinities. □Calcareous algae, Problematica, Dasycladales, Cyclocriniteae, Receptaculitales, morphology, classification, paleoecology, paleogeography.

receptaculitid paleoecology algae dasyclad


Bustylus (Eutheria, Adapisoriculidae) and the absence of ascertained marsupials in the Palaeocene of Europe

Abstract: The recent description of the new adapisoriculid placental Bustylus cernaysi from the Thanetian of Cernay, and possibly of Walbeck, permits a new assessment of the systematic position of the supposed marsupial ‘Peradectes’ marandati from the Montian of Hainin (Belgium). The affinity between the two species is demonstrated and the species ‘P.’ marandati is included in the genus Bustylus (family Adapisoriculidae) and is excluded from the direct ancestry of B. cernaysi only because of the apparent absence of the D cusp in the known sample. Comparison with the oldest known placental, Prokennalestes (otlestid), supports the eutherian nature of Bustylus marandati and B. cernaysi. It also shows that the adapisoriculids are morphologically closer to the primitive otlestids than to the paleoryctids, which are more specialized in several respects. One general conclusion is the absence of known marsupials in the Palaeocene of Europe, their occurrence in this continent being ascertained only from the beginning of the Eocene (i.e. early Sparnacian or MP 7 reference level).

marsupial
palaeocene
europe
genus bustylus


A giant nektobenthic radiodont from the Burgess Shale and the significance of hurdiid carapace diversity

Abstract: Radiodonts, stem-group euarthropods that evolved during the Cambrian explosion, were among the largest and most diversified lower palaeozoic predators. These animals were widespread geographically, occupying a variety of ecological niches, from benthic foragers to nektonic suspension feeders and apex predators. Here, we describe the largest Cambrian hurdiid radiodont known so far, Titanokorys gainesi, gen. et sp. nov., from the Burgess Shale (Marble Canyon, Kootenay National Park, British Columbia). Estimated to reach half a metre in length, this new species bears a very large ovoid-shaped central carapace with distinct short posterolateral processes and an anterior spine. Geometric morphometric analyses highlight the high diversity of carapace shapes in hurdiids and show that Titanokorys bridges a morphological gap between forms with long and short carapaces. Carapace shape, however, is prone to homoplasy and shows no consistent relationship with trophic ecology, as demonstrated by new data, including a reappraisal of the poorly known Pahvantia. Despite distinct carapaces, Titanokorys shares similar rake-like appendages for sediment-sifting with Cambroraster, a smaller but much more abundant sympatric hurdiid from the Burgess Shale. The co-occurrence of these two species on the same bedding planes highlights potential competition for benthic resources and the high diversity of large predators sustained by Cambrian communities.


A functional interpretation of the masticatory system and paleoecology of entelodonts

Abstract: Entelodonts are medium to large (perhaps 150–750 kg) Oligocene–Miocene bunodont artiodactyls with unique crania but typical artiodactyl postcrania. Functional and ecological interpretations are difficult because there is no clear modern analog to an entelodont in size, dentition, and cranial morphology. Entelodont crania combine primitive and derived features, including laterally expanded zygomatic arch/large temporal fossa (suggesting a large temporalis muscle), unreduced dental formula, long premolar row, fused mandibular symphysis, isognathy, and subcylindrical dentary condyles. Furthermore, the cranium has unique architectural and ontogenetic aspects unparalleled in extant mammals. Canines show heavy, carnivoran-like, apical wear in old individuals, suggesting regular contact with food. Conical premolars and associated diastemata dominate the tooth row. Premolars are often apically worn, in a fashion somewhat like those of carnivorans (e.g., Crocuta, Borophagus). Molars are low-cusped crushing teeth. Wide gape, indicated by the form of the coronoid process and temporal fossa, facilitated canine and premolar use, probably both in feeding and in social behavior. Jaw mechanics, tooth morphology, and tooth wear are compatible with omnivory and probable scavenging, an intriguing proposition for the huge Dinohyus hollandi.

entelodont
dentition
cranial morphology
canine
wide gape


Pterosaur tracks from the latest Campanian Cerro del Pueblo Formation of southeastern Coahuila, Mexico

Abstract: Abstract A new vertebrate tracksite in southeastern Coahuila, northern México, known as the El Pelillal tracksite (Latest Campanian, Cerro del Pueblo Formation) has yielded an important ichnofauna that includes the tracks of turtles, crocodilians, a small theropod dinosaur, a mammal-like organism and the tracks of pterosaurs. The pterosaurian manus impressions share an extraordinary similarity, in size and morphology, with the Jurassic ichnogenus Pteraichnus Stokes 1957 and are referred to Pteraichnus sp.; however, the pes impressions differ in that they are rather very elongated. According to the geological features and ichnofauna the El Pelillal tracksite represents a shallow, freshwater or lacustrine deposit, which agrees with our knowledge about the habitat preference of Cretaceous pterosaurs. This newly discovered tracksite in southeastern Coahuila, Mexico, offers great potential for palaeoichnological research and is thus becoming important in the understanding of the palaeoecosystems during the Late Cretaceous in southern North America.


Northern Hemisphere megafossil of Dacrycarpus (Podocarpaceae) from the Miocene of South China and its evolutionary and paleoecological implications

Abstract: The modern genus Dacrycarpus (Endl.) de Laub. of the family Podocarpaceae, containing nine species, is mainly distributed in tropical mountain rainforests of the southwestern Pacific region, ranging from New Zealand to low‐latitude Asia. This genus has abundant fossil records in both hemispheres, but all the known megafossils were limited to Australasia and South America. Here we report on Dacrycarpus guipingensis sp. nov. from the Miocene Erzitang Formation of Guangxi, South China. This is the first megafossil of Dacrycarpus in the Northern Hemisphere. The new species is represented by mummified dimorphic foliage, ovuliferous shoots, and a male cone with in situ pollen. It resembles the extant Dacrycarpus imbricatus (Blume) de Laub., which is common in rainforests from southern China and northern Myanmar to Fiji. This paper presents the first data on the anatomical structure of seed cone and exine ultrastructure of Dacrycarpus in situ pollen grains from a fossil material by using computed tomography scanning and ultrathin sectioning. For comparative purpose, data on the pollen morphology and ultrastructure were obtained for modern D. imbricatus for the first time. The D. guipingensis fossils strongly suggest the Miocene arrival of Dacrycarpus in Asia from the Southern Hemisphere. Based on the modern ecological niche and related fossil elements, this fossil locality was probably covered by conifer–broad‐leaved mountain rainforests during the Miocene.


A modeling assessment of the interplay between aeolian iron fluxes and iron-binding ligands in controlling carbon dioxide fluctuations during Antarctic warm events

Abstract: [1] We add a prognostic biogeochemical model to the Bern3D ocean circulation model to test the impact of increased aeolian iron fluxes in various regions of the ocean on long time scales. Atmospheric CO2 is most sensitive when modern dust flux is increased 100-fold in the Southern Ocean for 1000 years, resulting in a reduction of 10 ppmv. Seeding the Indian Ocean and South Pacific results in increased export production and CO2 drawdown in the Southern Ocean due to interbasinal transport of iron. The non-sea-salt calcium record from Dome C, Antarctica, is used to scale aeolian iron deposition in the Southern Ocean in transient simulations over four Antarctic warm events of the last glacial period. Our results suggest changes in dust flux to the Southern Ocean played a limited role in modulating CO2 variations. The impact of iron fluxes on CO2 is dependent on parameter values chosen for the iron-binding ligand.

aeolian iron flux
iron-binding ligand
antarctic warm event
ocean


LEAF MARGIN ANALYSIS: A NEW EQUATION FROM HUMID TO MESIC FORESTS IN CHINA

Abstract: Abstract Leaf margin analysis (LMA) is a widely used method that applies present-day linear correlation between the proportion of woody dicotyledonous species with untoothed leaves (P) and mean annual temperature (MAT) to estimate paleotemperatures from fossil leaf floras. Previous works demonstrate that LMA shows regional constraints and to date, no equation has been modeled directly from Chinese forests. Fifty humid to mesic Chinese forests were chosen to understand the relationship between percentage of untoothed leaf species and MAT in China. Consistent with previous studies, the Chinese data indicate that P shows a strong linear correlation with MAT, but the actual relationship is a little different from those recognized from other regions. Among the several currently used LMA equations, the one resulting from North and Central American and Japanese data, rather than the widely used East Asian LMA equation, yields the closest values to the actual MATs of the Chinese samples (mean absolute error = 1.9 °C). A new equation derived from the Chinese forests is therefore developed, where MAT = 1.038 + 27.6 × P. This study not only demonstrates the similarity of the relationship between P and MAT in the Northern Hemisphere, but also improves the reliability of LMA for paleoclimate reconstructions of Chinese paleofloras.

new equation
china
lma
annual temperature
leaf margin analysis


Anatomy and Taxonomic Status of the Chasmosaurine Ceratopsid Nedoceratops hatcheri from the Upper Cretaceous Lance Formation of Wyoming, U.S.A

Abstract: Background The validity of Nedoceratops hatcheri, a chasmosaurine ceratopsid dinosaur known from a single skull recovered in the Lance Formation of eastern Wyoming, U.S.A., has been debated for over a century. Some have argued that the taxon is an aberrant Triceratops, and most recently it was proposed that N. hatcheri represents an intermediate ontogenetic stage between “young adult” and “old adult” forms of a single taxon previously split into Triceratops and Torosaurus. Methodology/Principal Findings The holotype skull of Nedoceratops hatcheri was reexamined in order to map reconstructed areas and compare the specimen with other ceratopsids. Although squamosal fenestrae are almost certainly not of taxonomic significance, some other features are unique to N. hatcheri. These include a nasal lacking a recognizable horn, nearly vertical postorbital horncores, and relatively small parietal fenestrae. Thus, N. hatcheri is tentatively considered valid, and closely related to Triceratops spp. The holotype of N. hatcheri probably represents an “old adult,” based upon bone surface texture and the shape of the horns and epiossifications on the frill. In this study, Torosaurus is maintained as a genus distinct from Triceratops and Nedoceratops. Synonymy of the three genera as ontogenetic stages of a single taxon would require cranial changes otherwise unknown in ceratopsids, including additions of ossifications to the frill and repeated alternation of bone surface texture between juvenile and adult morphotypes. Conclusions/Significance Triceratops, Torosaurus, and likely Nedoceratops, are all distinct taxa, indicating that species richness for chasmosaurine ceratopsids in the Lance Formation just prior to the Cretaceous-Paleocene extinction was roughly equivalent to that earlier in the Cretaceous.

nedoceratops hatcheri
ontogenetic stage
torosaurus


Border Cave and the beginning of the Later Stone Age in South Africa

Abstract: The transition from the Middle Stone Age (MSA) to the Later Stone Age (LSA) in South Africa was not associated with the appearance of anatomically modern humans and the extinction of Neandertals, as in the Middle to Upper Paleolithic transition in Western Europe. It has therefore attracted less attention, yet it provides insights into patterns of technological evolution not associated with a new hominin. Data from Border Cave (KwaZulu-Natal) show a strong pattern of technological change at approximately 44–42 ka cal BP, marked by adoption of techniques and materials that were present but scarcely used in the previous MSA, and some novelties. The agent of change was neither a revolution nor the advent of a new species of human. Although most evident in personal ornaments and symbolic markings, the change from one way of living to another was not restricted to aesthetics. Our analysis shows that: (i) at Border Cave two assemblages, dated to 45–49 and >49 ka, show a gradual abandonment of the technology and tool types of the post-Howiesons Poort period and can be considered transitional industries; (ii) the 44–42 ka cal BP assemblages are based on an expedient technology dominated by bipolar knapping, with microliths hafted with pitch from Podocarpus bark, worked suid tusks, ostrich eggshell beads, bone arrowheads, engraved bones, bored stones, and digging sticks; (iii) these assemblages mark the beginning of the LSA in South Africa; (iv) the LSA emerged by internal evolution; and (v) the process of change began sometime after 56 ka.

later stone age
south africa
border cave


A taxonomic revision of orthosternous scorpions from the English Coal Measures aided by x-ray micro-tomography (XMT)

Abstract: Fossil scorpion systematics -particularly that of the diverse assemblage found in Carboniferous Coal Measure deposits -are problematic, being characterised by a large number of frequently monotypic taxa, based on a limited set of characters. These Palaeozoic scorpions have the potential to elucidate the nature of the scorpion stemgroup and hence to inform long running debates regarding the origin of the crown group and relationships between extant lineages. Carboniferous taxa are often found in siderite concretions and can be preserved in three dimensions. This study investigates two such fossils of the species Compsoscorpius buthiformis (Pocock, 1911) with the aid of X-ray Micro-Tomography (XMT) and computer reconstruction. These scans reveal important new details of the anatomy, such as the walking legs, that allow more detailed comparison with coeval taxa. Many of these taxa are revealed here to be junior synonyms of C. buthiformis and previous taxonomic practice, as it relates to Coal Measures scorpions, is criticised. The ecology of C. buthiformis is also reviewed in light of the new evidence from XMT. In particular, aspects of its walking leg and metastomal anatomy are analogous to that of extant lithophilic and 'errant' leaf-litter scorpions.

scorpion
x-ray micro-tomography
xmt
synonym


Meridional shifts in the marine ITCZ and the tropical hydrologic cycle over the last three glacial cycles

Abstract: [1] Paleoproxy studies show a strong correlation between tropical climate and high-latitude temperature variability recorded in the Greenland ice cores over the last glacial cycle. In particular, abrupt cooling events in the Greenland Ice Sheet Project II δ18O ice record appear synchronous with a southward migration of the Intertropical Convergence Zone (ITCZ) in the Atlantic, a weakening of the Indian and East Asian monsoon systems, and a strengthening of the South American monsoon system. Because this high-to-low-latitude climate teleconnection significantly alters the tropical hydrologic cycle around the globe, it plays a critical role in regulating global climate on glacial-interglacial time scales. We compare δ18Oseawater reconstructions (a salinity proxy generated from previously published Mg/Ca and oxygen isotope data on Globigerinoides ruber (white var.)) obtained from western Caribbean core ODP 999A and western equatorial Pacific core 806B across the last three glacial cycles to show that systematic variations in surface salinity at these sites suggest the tropical Hadley cell hydrologic system undergoes systematic reorganizations that differ dramatically between warm interglacial and cold glacial periods. Furthermore, cross-spectral and phase angle analyses of the ice-volume-corrected Caribbean and western Pacific δ18OSW records reveal a 100 kyr frequency in both records that is almost 180° out of phase and a 23 kyr frequency that is nearly in phase. This results in the development of a very large δ18OSW gradient between the Caribbean and the western equatorial Pacific on glacial-interglacial time scales that is best explained by a southward shift in both the Atlantic and Pacific ITCZ during North Atlantic cold phases.

itcz
tropical hydrologic cycle
glacial cycle
intertropical convergence zone


Burmese (Myanmar) amber checklist and bibliography 2018

Abstract: A list of all known taxa described or recorded from Burmese amber from the published literature up to the end of 2018 is given, along with a comprehensive bibliography. The history of the study of inclusions is summarised, and demonstrates that the number of species has risen exponentially over the past two decades. The first three species were named in 1916 and by the end of 1920 a total of 42 species had been named by T.D.A. Cockerell. Only three more species were named by 1999 though by the end of 2018 the total had risen to an incredible 1,192 species, of which over half were named in the past three years. Some 320 species were named in 2018, the highest number described from one type of amber in any one year in the entire history of amber studies.

myanmar
bibliography
burmese amber
arthropod


Carbon, nitrogen, and oxygen stable isotopes in modern tooth enamel: A case study from Gorongosa National Park, central Mozambique

Abstract: The analyses of the stable isotope ratios of carbon (δ13C), nitrogen (δ15N), and oxygen (δ18O) in animal tissues are powerful tools for reconstructing the feeding behavior of individual animals and characterizing trophic interactions in food webs. Of these biomaterials, tooth enamel is the hardest, most mineralized vertebrate tissue and therefore least likely to be affected by chemical alteration (i.e., its isotopic composition can be preserved over millions of years), making it an important and widely available archive for biologists and paleontologists. Here, we present the first combined measurements of δ13C, δ15N, and δ18O in enamel from the teeth of modern fauna (herbivores, carnivores, and omnivores) from the well-studied ecosystem of Gorongosa National Park (GNP) in central Mozambique. We use two novel methods to produce high-precision stable isotope enamel data: (i) the “oxidation-denitrification method,” which permits the measurement of mineral-bound organic nitrogen in tooth enamel (δ15Nenamel), which until now, has not been possible due to enamel’s low organic content, and (ii) the “cold trap method,” which greatly reduces the sample size required for traditional measurements of inorganic δ13Cenamel and δ18Oenamel (from ≥0.5 to ≤0.1 mg), permitting analysis of small or valuable teeth and high-resolution serial sampling of enamel. The stable isotope results for GNP fauna reveal important ecological information about the trophic level, dietary niche, and resource consumption. δ15Nenamel values clearly differentiate trophic level (i.e., carnivore δ15Nenamel values are 4.0‰ higher, on average, than herbivores), δ13Cenamel values distinguish C3 and/or C4 biomass consumption, and δ18Oenamel values reflect local meteoric water (δ18Owater) in the park. Analysis of combined carbon, nitrogen, and oxygen stable isotope data permits geochemical separation of grazers, browsers, omnivores, and carnivores according to their isotopic niche, while mixed-feeding herbivores cannot be clearly distinguished from other dietary groups. These results confirm that combined C, N, and O isotope analyses of a single aliquot of tooth enamel can be used to reconstruct diet and trophic niches. Given its resistance to chemical alteration, the analysis of these three isotopes in tooth enamel has a high potential to open new avenues of research in (paleo)ecology and paleontology.

tooth enamel
mozambique
herbivore
carbon


Phylogenetic position of the crocodylian Megadontosuchus arduini and tomistomine palaeobiogeography

Abstract: A cladistic analysis of Megadontosuchus arduini from the middle Eocene of Monte Duello (NE Italy) confirms its tomistomine relationships, but the low number of scorable characters determines a low resolution within the tomistomine clade. However, Megadontosuchus is clearly distinct from the other Eocene European or North African tomistomines, in having a moderate elongated but robust rostrum, massive maxillary and dentary teeth and large supratemporal fenestrae. The rostrum and teeth characteristics could indicate that M. arduini had a degree of feeding specialization intermediate between Maroccosuchus zennaroi and the Eocene European tomistomines. A summary of tomistomine palaeobiogeography suggests that despite only one species with a rather restricted range survives at present, such a clade had a glorious past with a world wide distribution documented by a conspicuous fossil record that starts at least in the early Eocene. At present, a detailed knowledge of tomistomine palaeobiogeography is hindered by the lack of modern taxonomic revisions of some fossil remains and therefore by the poor understanding of phylogenetic relationships.

megadontosuchus arduini
tomistomine palaeobiogeography
eocene


Glaciation and sea-level change for Ireland and the Irish Sea since Late Devensian/Midlandian time

Abstract: The sea-level change around the coast of Ireland and the Irish Sea for the past 20 000 years is primarily the combined result of the glacio-isostatic adjustment of the crust to the removal of ice over the British Isles and the total eustatic change from the global ice sheets. However, the isostatic effects due to the removal of ice from northern Europe and North America and the addition of meltwater into the oceans also make a significant contribution. Predictions of sea-level change, based on glacio-hydro-isostatic models are compared with observations to constrain the ice volume over Ireland at the time of the last glacial maximum and the maximum ice height appears to have been of the order of 600 m. The models predict well the spatial variability in sea-level change observed across the region for Holocene and Lateglacial time, with levels above present being predicted only for northeastern Ireland and north of about Morecambe Bay. The models do not support suggestions that Lateglacial levels along the east coast of Ireland or the coast of Wales were 50–150 m above their present levels. Consistent models that would produce such large Lateglacial highstands are incompatible with all other sea level and glacial evidence for the British Isles. Palaeobathymetry and palaeoshoreline reconstructions for the Irish Sea indicates that a tenuous landbridge between Britain and Ireland developed only across the Celtic Sea, between about 18000 and 14000 years bp.

sea-level change
irish sea
ice sheet
glacial maximum


New proviverrine genus from the Early Eocene of Europe and the first phylogeny of Late Palaeocene–Middle Eocene hyaenodontidans (Mammalia)

Abstract: A new genus and new species of Proviverrinae from the Early Eocene of Europe, Morlodon vellerei, is described. This new taxon is morphologically close to the Middle Eocene genus Matthodon, with which it shares tendencies towards a robust dentition; the two genera also share the reduction of P1. In order to examine the phylogenetic relationships of the new genus Morlodon with Early and Middle Eocene European Proviverrinae, a phylogenetic analysis of the earliest hyaenodontidans was conducted. The taxa analysed range from Late Palaeocene to Middle Eocene and are from Africa, Asia, Europe and North America. The new phylogeny of earliest hyaenodontans clarifies the systematics of the paraphyletic assemblage ‘Proviverrinae’ and results in the recognition of five major clades. The monophyly of the Limnocyoninae and Koholiinae is supported, and two new subfamilies are erected from the ‘Proviverrinae’: Sinopaninae and Arfianinae. A new definition of the Proviverrinae is proposed: only European hyaenodontidans from Early and Middle Eocene are included in this subfamily. However, the phylogenetic relationships between the five subfamilies remain to be established. An ancestral morphotype for the Hyaenodontida is proposed in order to identify the different subfamilies. On the basis of the analysis and of data presently available, an African origin for Hyaenodontida is proposed. Hyaenodontidans are involved in the faunal dispersals that occurred around the Palaeocene–Eocene (P/E) boundary. They dispersed from Africa to Asia during the Late Palaeocene (Limnocyoninae), and at the P/E boundary from Africa to Europe (Proviverrinae) and to North America through Europe (Sinopaninae and Arfianinae). Proviverrinae remain an endemic European group, whereas Sinopaninae, Limnocyoninae and Arfianinae mainly evolved in North America. Koholiinae represents the sole endemic African group. The probable African origin of the Hyaenodontida supports the diphyletism of ‘Creodonta’ and abandonment of this taxon. http://zoobank.org/urn:lsid:zoobank.org:pub:450D4FAB-42F0-4824-9DE0-DEED591C0D14

early eocene
phylogeny
hyaenodontidan
proviverrinae


Respiration, dissolution, and the lysocline

Abstract: [1] Here I synthesize the results of several types of measurements of organic carbon respiration and calcium carbonate dissolution rates in pelagic seafloor sediments. Measurements of pore water oxygen demonstrate that most of the respiration takes place very near the sediment-water interface, with a scale depth of a few millimeters. The remainder of the oxic respiration occurs much deeper in the sediments, with a scale depth of several centimeters. All measures of respiration from locations as disparate as the tropical Pacific and Atlantic, and the subtropical North Atlantic agree that pelagic seafloor rates of oxic respiration of organic carbon are relatively independent of depth and location, with the exception of sediments beneath the Pacific eastern equatorial upwelling zone. Calcite dissolution in seafloor sediments requires forcing by respiration-produced CO2, and rates are consistent with a first-order dependence on pore water undersaturation, solubility as determined by Mucci [1983] at atmospheric pressure, and locally variable mass-specific dissolution rate constants. Respiration-driven calcite dissolution fluxes predicted by this combination of respiration and dissolution rate expressions are significantly lower than many previous estimates. Comparison of dissolution fluxes in the oligotrophic open ocean measured by other researchers with benthic chamber incubation techniques with those predicted by this combination of rate expressions is, within stated uncertainties, in agreement in all but one case, questioning the need for complicated mechanisms such as surface buffering or authigenic precipitation to explain seafloor calcite diagenesis. Applying these kinetics to a simple one-dimensional, steady state model of the bulk calcite content and sediment accumulation rates of the sediment mixed layer yields results consistent with observations of the seafloor lysocline, the region of transition from high calcite to low-calcite sediments, on the Ceara Rise in the western tropical North Atlantic and the Ontong-Java Plateau in the western equatorial Pacific. Scenarios ignoring dissolution driven by respiration-produced CO2 in pore waters and using the high-order dependence on undersaturation and very large dissolution rate constants implied by some earlier laboratory studies do not simulate these observations. While the scheme represented here does, in fact, imply a strong shift in the locus of carbonate dissolution toward the sediment water interface as bottom-water saturation decreases, as implied by the observations of Martin et al. [2000], no simple combination of sediment transport coefficients and reaction kinetics can reproduce the observation of increasing 14C age as dissolution progresses. These results emphasize the importance of accurate knowledge of the kinetics of respiration and dissolution to interpretation of either the present-day or paleolysocline.

dissolution
lysocline
carbonate dissolution
seafloor sediment
respiration


Computational biomes: The ecometrics of large mammal teeth

Abstract: As organisms are adapted to their environments, assemblages of taxa can be used to describe environments in the present and in the past. Here, we use a data mining method, namely redescription mining, to discover and analyze patterns of association between large herbivorous mammals and their environments via their functional traits. We focus on functional properties of animal teeth, characterized using a recently developed dental trait scoring scheme. The teeth of herbivorous mammals serve as an interface to obtain energy from food, and are therefore expected to match the types of plant food available in their environment. Hence, dental traits are expected to carry a signal of environmental conditions. We analyze a global compilation of occurrences of large herbivorous mammals and of bioclimatic conditions. We identify common patterns of association between dental traits distributions and bioclimatic conditions and discuss their implications. Each pattern can be considered as a computational biome. Our analysis distinguishes three global zones, which we refer to as the boreal-temperate moist zone, the tropical moist zone and the tropical-subtropical dry zone. The boreal-temperate moist zone is mainly characterized by seasonal cold temperatures, a lack of hypsodonty and a high share of species with obtuse lophs. The tropical moist zone is mainly characterized by high temperatures, high isothermality, abundant precipitation and a high share of species with acute rather than obtuse lophs. Finally, the tropical dry zone is mainly characterized by a high seasonality of temperatures and precipitation, as well as high hypsodonty and horizodonty. We find that the dental traits signature of African rain forests is quite different from the signature of climatically similar sites in North America and Asia, where hypsodont species and species with obtuse lophs are mostly absent. In terms of climate and dental signatures, the African seasonal tropics share many similarities with Central-South Asian sites. Interestingly, the Tibetan plateau is covered both by redescriptions from the tropical-subtropical dry group and by redescriptions from the boreal-temperate moist group, suggesting a combination of features from both zones in its dental traits and climate.

computational biome
tooth
evolutionary framework
palaeobiology
functional interpretation