Belowground rhizomes in paleosols: The hidden half of an Early Devonian vascular plant

Abstract: Significance The roots and rhizomes of early vascular plants, and their interactions with soils, are poorly documented. Here we report on the complex, belowground rhizome systems of an Early Devonian plant, and their contribution to the formation of the earliest record of rooted red-bed soils in Asia. Our specimens predate the earliest trees with deep roots from the Middle Devonian by 20 million years. We propose that plant rhizomes have long functioned in terrestrial ecosystems, playing important roles in shaping Earth’s environments by reducing soil erosion rates and thereby increasing the stability of land surface and resilience of plant communities. The colonization of terrestrial environments by rooted vascular plants had far-reaching impacts on the Earth system. However, the belowground structures of early vascular plants are rarely documented, and thus the plant−soil interactions in early terrestrial ecosystems are poorly understood. Here we report the earliest rooted paleosols (fossil soils) in Asia from Early Devonian deposits of Yunnan, China. Plant traces are extensive within the soil and occur as complex network-like structures, which are interpreted as representing long-lived, belowground rhizomes of the basal lycopsid Drepanophycus. The rhizomes produced large clones and helped the plant survive frequent sediment burial in well-drained soils within a seasonal wet−dry climate zone. Rhizome networks contributed to the accumulation and pedogenesis of floodplain sediments and increased the soil stabilizing effects of early plants. Predating the appearance of trees with deep roots in the Middle Devonian, plant rhizomes have long functioned in the belowground soil ecosystem. This study presents strong, direct evidence for plant−soil interactions at an early stage of vascular plant radiation. Soil stabilization by complex rhizome systems was apparently widespread, and contributed to landscape modification at an earlier time than had been appreciated.

paleosol
vascular plant
terrestrial environment
belowground rhizome


Sea-level, humidity, and land-erosion records across the initial Eocene thermal maximum from a continental-marine transect in northern Spain

Abstract: In two continental sections in the Tremp basin, northern Spain, the initial Eocene thermal maximum (also known as the Paleocene-Eocene thermal maximum) is registered by an ∼6‰ fall in δ 1 3 C values in soil carbonate nodules. High-resolution correlations, using the δ 1 3 C excursion, can be made to nearby shelf and bathyal marine settings, allowing a detailed reconstruction of soil formation on land and transport of detritus to the sea during the initial Eocene thermal maximum. Soils that formed before and after the initial Eocene thermal maximum in the Tremp region reflect arid to semiarid conditions, with abundant evaporative minerals, whereas initial Eocene thermal maximum soils reflect seasonally wetter but generally dry conditions. During the initial Eocene thermal maximum, land erosion was intensified and accumulation rates of terrigenous detritus in the sea increased. This reflects both increased topographic relief associated with a prominent sea-level lowstand and enhanced seasonal precipitation over a dry landscape with sparse vegetation. Deeper erosion led to an increase in the flux of kaolinite from buried Mesozoic soils to the oceans. The association of the initial Eocene thermal maximum with a sea-level lowstand in northern Spain, as well as at other marginal North Atlantic sites, may reflect coeval large-scale magmatic activity in the northernmost Atlantic.

eocene thermal maximum
northern spain
soil carbonate nodule


Vital effects in coccolith calcite: Cenozoic climate‐pCO2 drove the diversity of carbon acquisition strategies in coccolithophores?

Abstract: [1] Coccoliths, calcite plates produced by the marine phytoplankton coccolithophores, have previously shown a large array of carbon and oxygen stable isotope fractionations (termed “vital effects”), correlated to cell size and hypothesized to reflect the varying importance of active carbon acquisition strategies. Culture studies show a reduced range of vital effects between large and small coccolithophores under high CO2, consistent with previous observations of a smaller range of interspecific vital effects in Paleocene coccoliths. We present new fossil data examining coccolithophore vital effects over three key Cenozoic intervals reflecting changing climate and atmospheric partial pressure of CO2 (pCO2). Oxygen and carbon stable isotopes of size-separated coccolith fractions dominated by different species from well preserved Paleocene-Eocene thermal maximum (PETM, ∼56 Ma) samples show reduced interspecific differences within the greenhouse boundary conditions of the PETM. Conversely, isotope data from the Plio-Pleistocene transition (PPT; 3.5–2 Ma) and the last glacial maximum (LGM; ∼22 ka) show persistent vital effects of ∼2‰. PPT and LGM data show a clear positive trend between coccolith (cell) size and isotopic enrichment in coccolith carbonate, as seen in laboratory cultures. On geological timescales, the degree of expression of vital effects in coccoliths appears to be insensitive topCO2 changes over the range ∼350 ppm (Pliocene) to ∼180 ppm (LGM). The modern array of coccolith vital effects arose after the PETM but before the late Pliocene and may reflect the operation of more diverse carbon acquisition strategies in coccolithophores in response to decreasing Cenozoic pCO2.

carbon acquisition strategy
coccolithophore
vital effect


An astronomical time scale for the Maastrichtian based on the Zumaia and Sopelana sections (Basque country, northern Spain)

Abstract: The rhythmically bedded limestone–marl alternations in the coastal cliffs of Sopelana and Zumaia in the Basque country, northern Spain, permit testing and refining of existing Maastrichtian chronologies (latest Cretaceous). The recently established astronomical time scale for the late Maastrichtian at Zumaia is extended into C31n with the integrated stratigraphy of the Sopelana section. The cyclic alternations of hemipelagic limestones and marls at Sopelana show a strong influence of eccentricity-modulated precession. Together, the Zumaia and Sopelana sections span almost the entire Maastrichtian, and encompass thirteen 405 kyr cycles spanning a total duration of 5.3 myr. From the Cretaceous–Paleogene (K–Pg) boundary downwards, 405 kyr minima in the lithological, magnetic susceptibility and reflectance data records are tuned to successive 405 kyr minima in the new La2011 eccentricity solution. Assuming a K–Pg boundary age of 65.97 Ma, we present orbitally tuned ages of biostratigraphic and magnetostratigraphic events. Whereas the bases of Chrons C29r and C30n were reliably established at Zumaia and are in good agreement with previous studies, new data from Sopelana provide a refinement of the basal age of Chron C31r. Additional planktonic foraminifera and calcareous nannoplankton data from Zumaia, and new calcareous nannoplankton data from Sopelana, allow for worldwide correlation of the cyclostratigraphy of the Basque country. Supplementary materials: A geological map and additional data are available at www.geolsoc.org.uk/SUP18696.

astronomical time scale
maastrichtian
northern spain


Ontogenetic variation in the skull of Stenopterygius quadriscissus with an emphasis on prenatal development

Abstract: The availability of a large sample size from a range of ontogenetic stages makes Stenopterygius quadriscissus a good model to study ontogenetic variation in a fossil sauropsid. We qualitatively examined pre- and postnatal ontogenetic changes in the cranium of S. quadriscissus. The prenatal ossification sequence is similar to other diapsids, exhibiting delayed chondrocranial ossification compared to the dermatocranium. In the dermatocranium, the circumorbital area is more ossified earlier in development relative to other elements, especially those of the skull roof where ossification is comparatively weaker across prenatal stages. Perinatally all cranial elements are ossified, and many scarf and step joints are already closed. We propose four prenatal and three postnatal stages in S. quadriscissus on the basis of relative ossification, size and qualitative cranial characters pertaining to the jugal, parietal, frontal, pterygoid and surangular. These will provide a basis for determining ontogenetic stages in other ichthyosaurs. Moreover, our postnatal observations aid in refining ontogenetic characters for phylogenetic studies. Lastly, we observed that the antimeric sutures of the midline of the skull roof are open perinatally and that fusion of the midline only appears in the adult stage. We hypothesize that the loose connection of the midline functions as a fontanelle, limiting potential damage during birth.

stenopterygius quadriscissus
prenatal development
ossification
birth
ontogenetic variation


Taphonomy of a modern shrimp: implications for the arthropod fossil record

Abstract: Every living organism represents a potentialfossil, although only a few are ever successfully fossilized. Taphonomic studies should explain episodes of both fossilization and of non-fossilization. This paper examines some of the taphonomic variables that may bias the arthropod fossil record. The short-term preservation potential of the modern carid shrimp, Pandalus danae, was studied in a variety of laboratory and field settings. Freshly killed specimens were buried at two intertidal localities on San Juan Island, Puget Sound, Washington. Carcasses were buried at depths of 5-20 cm for periods of one day to three weeks. Destruction by scavengers (crabs?) was the probable primary cause of carcass destruction. Further breakdown was caused by bacterial decomposition and disturbance by burrowing infauna. Shrimp remains were placed in a series of glass jars in the laboratory. Jars differed in the presence and kind of enclosed sediment and in the degree of aeration. Decomposition destroyed nearly all soft tissues within a period of two weeks. The cuticle became extremely soft, resulting in loss of physical integrity of the remains. Differences between oxic and anoxic decomposition were minor. These results, along with a consideration of the biological, physical, and chemical effects of bioturbation, suggest that disturbance by scavengers or burrowing infauna is a majorfactor in the destruction of buried arthropod remains. The absence or inhibition of bioturbation may be a necessary condition for arthropod preservation. The preservation potential of arthropods, and of other soft-bodied forms, may have declined since the Paleozoic.


Probabilistic divergence time estimation without branch lengths: dating the origins of dinosaurs, avian flight and crown birds

Abstract: Branch lengths—measured in character changes—are an essential requirement of clock-based divergence estimation, regardless of whether the fossil calibrations used represent nodes or tips. However, a separate set of divergence time approaches are typically used to date palaeontological trees, which may lack such branch lengths. Among these methods, sophisticated probabilistic approaches have recently emerged, in contrast with simpler algorithms relying on minimum node ages. Here, using a novel phylogenetic hypothesis for Mesozoic dinosaurs, we apply two such approaches to estimate divergence times for: (i) Dinosauria, (ii) Avialae (the earliest birds) and (iii) Neornithes (crown birds). We find: (i) the plausibility of a Permian origin for dinosaurs to be dependent on whether Nyasasaurus is the oldest dinosaur, (ii) a Middle to Late Jurassic origin of avian flight regardless of whether Archaeopteryx or Aurornis is considered the first bird and (iii) a Late Cretaceous origin for Neornithes that is broadly congruent with other node- and tip-dating estimates. Demonstrating the feasibility of probabilistic time-scaling further opens up divergence estimation to the rich histories of extinct biodiversity in the fossil record, even in the absence of detailed character data.

branch length
avian flight
crown bird
node


Fossil and genomic evidence constrains the timing of bison arrival in North America

Abstract: Significance The appearance of bison in North America is both ecologically and paleontologically significant. We analyzed mitochondrial DNA from the oldest known North American bison fossils to reveal that bison were present in northern North America by 195–135 thousand y ago, having entered from Asia via the Bering Land Bridge. After their arrival, bison quickly colonized much of the rest of the continent, where they rapidly diversified phenotypically, producing, for example, the giant long-horned morphotype Bison latifrons during the last interglaciation. The arrival of bison in North America marks one of the most successful large-mammal dispersals from Asia within the last million years, yet the timing and nature of this event remain poorly determined. Here, we used a combined paleontological and paleogenomic approach to provide a robust timeline for the entry and subsequent evolution of bison within North America. We characterized two fossil-rich localities in Canada’s Yukon and identified the oldest well-constrained bison fossil in North America, a 130,000-y-old steppe bison, Bison cf. priscus. We extracted and sequenced mitochondrial genomes from both this bison and from the remains of a recently discovered, ∼120,000-y-old giant long-horned bison, Bison latifrons, from Snowmass, Colorado. We analyzed these and 44 other bison mitogenomes with ages that span the Late Pleistocene, and identified two waves of bison dispersal into North America from Asia, the earliest of which occurred ∼195–135 thousand y ago and preceded the morphological diversification of North American bison, and the second of which occurred during the Late Pleistocene, ∼45–21 thousand y ago. This chronological arc establishes that bison first entered North America during the sea level lowstand accompanying marine isotope stage 6, rejecting earlier records of bison in North America. After their invasion, bison rapidly colonized North America during the last interglaciation, spreading from Alaska through continental North America; they have been continuously resident since then.

north america
steppe bison
bison dispersal
morphological diversification


Homo naledi and Pleistocene hominin evolution in subequatorial Africa

Abstract: New discoveries and dating of fossil remains from the Rising Star cave system, Cradle of Humankind, South Africa, have strong implications for our understanding of Pleistocene human evolution in Africa. Direct dating of Homo naledi fossils from the Dinaledi Chamber (Berger et al., 2015) shows that they were deposited between about 236 ka and 335 ka (Dirks et al., 2017), placing H. naledi in the later Middle Pleistocene. Hawks and colleagues (Hawks et al., 2017) report the discovery of a second chamber within the Rising Star system (Dirks et al., 2015) that contains H. naledi remains. Previously, only large-brained modern humans or their close relatives had been demonstrated to exist at this late time in Africa, but the fossil evidence for any hominins in subequatorial Africa was very sparse. It is now evident that a diversity of hominin lineages existed in this region, with some divergent lineages contributing DNA to living humans and at least H. naledi representing a survivor from the earliest stages of diversification within Homo. The existence of a diverse array of hominins in subequatorial comports with our present knowledge of diversity across other savanna-adapted species, as well as with palaeoclimate and paleoenvironmental data. H. naledi casts the fossil and archaeological records into a new light, as we cannot exclude that this lineage was responsible for the production of Acheulean or Middle Stone Age tool industries. DOI: http://dx.doi.org/10.7554/eLife.24234.001


High niche diversity in Mesozoic pollinating lacewings

Abstract: Niche diversity of pollinating insects plays a vital role in maintaining extant terrestrial ecosystems. A key dimension of pollination niches refers to the insect proboscis length that commonly matches the floral tube length. Here we describe new kalligrammatid lacewings (an iconic Mesozoic pollinating insect lineage) from late Cretaceous Burmese amber and Mesozoic sediments in China. Kalligrammatids display complex configurations of elongate mouthpart elements consisting of well-developed maxillae, labium and their palps. The mouthpart lengths vary among species, from 0.6 to 18.0 mm, suggesting corresponding variability in the floral tube lengths of Mesozoic plants. With the diversification of pollinating habits, the kalligrammatids presented highly divergent traits related to chemical communication and defence mechanisms. Together with other Mesozoic long-proboscid insects, these fossils not only reveal the high niche diversity of Mesozoic pollinating insects but also highlight the diversity of Mesozoic pollinator-dependent plants prior to the rise of angiosperms.


Hitchcock's Leptodactyli, Penetrative Tracks, and Dinosaur Footprint Diversity

Abstract: ABSTRACT Starting with his first report on fossil footprints from the Connecticut Valley over 180 years ago, Edward Hitchcock described what he interpreted as a burgeoning ancient fauna founded on ever-increasing nominal track diversity. For three decades, Hitchcock made countless contributions to ichnology, but his inference of thin-toed animals (Leptodactyli) from thin-toed tracks is flawed by modern criteria. Leptodactylous tracks are now recognized as variants made by thick-toed feet penetrating into soft, collapsing substrates. Herein, we take a closer look at the creation of such penetrative tracks using computer simulations of particle flow. Classic specimens are used to demonstrate how different modes of surface presentation make penetrative tracks challenging to recognize and interpret. Evaluation of 266 specimens from 43 leptodactylous ichnotaxa reveals that ∼90% are penetrative. We propose that a reliance on a single formation mechanism confounded Hitchcock's ability to reliably recognize different trackmakers. This is not an old problem applicable only to fossils collected long ago; domination of a transmission-based model continues to bias the field today. Most texts and many publications either omit collapsed penetrative tracks or fail to recognize them as a significant source of variation. Without proper regard for subsurface toe movement and sediment flow, inferences of foot shape from track shape can, as for Hitchcock, be led far astray. The misidentification and misunderstanding of penetrative tracks impact our conception of the diversity of life in the Early Jurassic, as well as in other ichnofaunas worldwide.

leptodactyli
penetrative track
hitchcock


The Impact of the Rate Prior on Bayesian Estimation of Divergence Times with Multiple Loci

Abstract: Bayesian methods provide a powerful way to estimate species divergence times by combining information from molecular sequences with information from the fossil record. With the explosive increase of genomic data, divergence time estimation increasingly uses data of multiple loci (genes or site partitions). Widely used computer programs to estimate divergence times use independent and identically distributed (i.i.d.) priors on the substitution rates for different loci. The i.i.d. prior is problematic. As the number of loci (L) increases, the prior variance of the average rate across all loci goes to zero at the rate 1/L. As a consequence, the rate prior dominates posterior time estimates when many loci are analyzed, and if the rate prior is misspecified, the estimated divergence times will converge to wrong values with very narrow credibility intervals. Here we develop a new prior on the locus rates based on the Dirichlet distribution that corrects the problematic behavior of the i.i.d. prior. We use computer simulation and real data analysis to highlight the differences between the old and new priors. For a dataset for six primate species, we show that with the old i.i.d. prior, if the prior rate is too high (or too low), the estimated divergence times are too young (or too old), outside the bounds imposed by the fossil calibrations. In contrast, with the new Dirichlet prior, posterior time estimates are insensitive to the rate prior and are compatible with the fossil calibrations. We re-analyzed a phylogenomic data set of 36 mammal species and show that using many fossil calibrations can alleviate the adverse impact of a misspecified rate prior to some extent. We recommend the use of the new Dirichlet prior in Bayesian divergence time estimation. [Bayesian inference, divergence time, relaxed clock, rate prior, partition analysis.]

multiple loci
average rate
dirichlet distribution


Environmentally driven extinction and opportunistic origination explain fern diversification patterns

Abstract:
Combining palaeontological and neontological data offers a unique opportunity to investigate the relative roles of biotic and abiotic controls of species diversification, and the importance of origination versus extinction in driving evolutionary dynamics. Ferns comprise a major terrestrial plant radiation with an extensive evolutionary history providing a wealth of modern and fossil data for modelling environmental drivers of diversification. Here we develop a novel Bayesian model to simultaneously estimate correlations between diversification dynamics and multiple environmental trajectories. We estimate the impact of different factors on fern diversification over the past 400 million years by analysing a comprehensive dataset of fossil occurrences and complement these findings by analysing a large molecular phylogeny. We show that origination and extinction rates are governed by fundamentally different processes: originations depend on within-group diversity but are largely unaffected by environmental changes, whereas extinctions are strongly affected by external factors such as climate and geology. Our results indicate that the prime driver of fern diversity dynamics is environmentally driven extinction, with origination being an opportunistic response to diminishing ecospace occupancy.
The world's biodiversity is the result of a complex interplay between biotic and abiotic drivers and their changes over time and space 1, 2 . Recent advances in paleontology and molecular phylogenetics have led to a renaissance in macroevolutionary research, but inherent biases in the fossil record and phylogenetic data often compromise inferences based on a single type of data 3 . Hence, the relative roles of different factors affecting species diversification, as well as the importance of origination versus extinction, remain contested 1-3 . Ferns are an unusually well-suited group to investigate these questions because of their high diversity throughout most of the history of terrestrial life 4, 5 , their rich fossil record [4] [5] [6] , and the well understood phylogenetic relationships among their extant members [7] [8] [9] [10] [11] .
Earlier, ferns were seen as a relict group with their heyday in the Palaeozoic and diminished importance towards the present, as they were gradually replaced by gymnosperms and angiosperms 4 . This view was challenged by molecular phylogenies revealing that the most diverse, predominantly epiphytic fern lineages diversified simultaneously with the angiosperms 12 . This has been taken as evidence for adaptive radiation of epiphytic ferns in angiosperm-dominated forests 12, 13 . Although these alternative views suggest contrasting interactions between ferns and angiosperms, they emphasize the importance of biotic factors in driving diversification as predicted by the "Red Queen" model of evolution 1, 14 . Other studies have linked fern diversification with the physical environment, by suggesting that warm and wet climates induced the simultaneous radiation of angiosperms and

origination
extinction rate
environmental change


Tropical ancient DNA reveals relationships of the extinct Bahamian giant tortoise Chelonoidis alburyorum

Abstract: Ancient DNA of extinct species from the Pleistocene and Holocene has provided valuable evolutionary insights. However, these are largely restricted to mammals and high latitudes because DNA preservation in warm climates is typically poor. In the tropics and subtropics, non-avian reptiles constitute a significant part of the fauna and little is known about the genetics of the many extinct reptiles from tropical islands. We have reconstructed the near-complete mitochondrial genome of an extinct giant tortoise from the Bahamas (Chelonoidis alburyorum) using an approximately 1 000-year-old humerus from a water-filled sinkhole (blue hole) on Great Abaco Island. Phylogenetic and molecular clock analyses place this extinct species as closely related to Galápagos (C. niger complex) and Chaco tortoises (C. chilensis), and provide evidence for repeated overseas dispersal in this tortoise group. The ancestors of extant Chelonoidis species arrived in South America from Africa only after the opening of the Atlantic Ocean and dispersed from there to the Caribbean and the Galápagos Islands. Our results also suggest that the anoxic, thermally buffered environment of blue holes may enhance DNA preservation, and thus are opening a window for better understanding evolution and population history of extinct tropical species, which would likely still exist without human impact.

ancient dna
chelonoidis alburyorum
extinct specie
mitochondrial genome
bahamas


New Fossil Remains from the Pliocene Koetoi Formation of Northern Japan Provide Insights Into Growth Rates and the Vertebral Evolution of Porpoises

Abstract: Extant porpoises (Phocoenidae) are odontocetes characterized by their small size, short and wide rostrum, late (or absent) completion of epiphyseal ankylosis in the vertebral column (= physical maturity), and short life cycles, all of which are thought to have resulted from progenetic evolution. We describe a small fossil phocoenid from the lower Pliocene Koetoi Formation of Hokkaido (northern Japan), preserving a small, narrow rostrum, as well as anteroposteriorly elongate thoracic and lumbar vertebral centra with completely fused epiphyses. Physical maturity in this specimen occurred significantly earlier than in extant phocoenids, as shown by dental data indicating that the specimen died at only four years of age. The difference between the present material and extant porpoises may be attributable to different growth rates during ontogeny. The long centra and caudally inclined neural spines of the specimen from Hokkaido are primitive characters among phocoenids. By contrast, the great height of its neural spines is highly derived, even among extant species, and suggestive of a fast swimmer. In terms of its vertebral morphology, the new specimen falls within a morphological continuum defined by the archaic Numataphocoena yamashitai and the highly derived vertebral morphology of Phocoenoides dalli. Phocoenid vertebral evolution has been complex and frequently convergent, as opposed to stepwise and unidirectional. The different vertebral morphologies of the new specimen and the contemporaneous extinct taxa Numataphocoena and Piscolithax longirostris indicate that they were adapted to different environments.

pliocene koetoi formation
northern japan
vertebral evolution


Carcasses on the coastline: measuring the ecological fidelity of the cetacean stranding record in the eastern North Pacific Ocean

Abstract: Abstract To understand how well fossil assemblages represent original communities, paleoecologists seek comparisons between death assemblages and their source communities. These comparisons have traditionally used nearshore, marine invertebrate assemblages for their logistical ease, high abundance, and comparable census data from living communities. For large marine vertebrates, like cetaceans, measuring their diversity in ocean ecosystems is difficult and expensive. Cetaceans, however, often beach or strand themselves along the coast, and archived data on stranded cetaceans have been recorded, in some areas, over several decades. If the stranding record is interpreted as a death assemblage, then the stranding record may represent a viable alternative for measuring diversity in living communities on directly adjacent coastlines. This study assessed the fidelity of the cetacean stranding record in the eastern North Pacific Ocean. The living community in this region has been studied for over 100 years and, recently, extensive and systematic live transect surveys using ship-based observing platforms have produced a valuable source of live diversity data. Over this same period, the U.S. Marine Mammal Stranding Program has collected and archived a record of cetacean strandings along the U.S. Pacific coastline, providing an ideal death assemblage for comparison. Using fidelity metrics commonly used in marine invertebrate taphonomy, I determined that the stranding record samples the living cetacean community with high fidelity, across fine and coarse taxonomic ranks, and at large geographic scales (>1000 km of coastline). The stranding record is also richer than the live surveys, with live-dead ratios between 1.1 and 1.3. The stranding record recovers similar rank-order relative abundances as live surveys, with statistical significance. Also, I applied sample-based rarefaction methods to generate collector's curves for strandings along the U.S. Pacific Coast to better evaluate the spatiotemporal characteristics of the stranding record. Results indicate that saturation (i.e., sampling >95% assemblage) at species, genus, and family levels occurs in less than five years of sampling, with families accumulating faster than species, and larger geographic regions (i.e., longer coastlines) accumulating taxa the most rapidly. The high fidelity of the stranding record, measured both in richness and by ranked relative abundance, implies that ecological structure from living cetacean communities is recorded in the death assemblage, a finding that parallels marine invertebrate assemblages, though at far larger spatial scales. These results have implications for studying cetacean ecology in both modern and ancient environments: first, these results imply that the stranding record, over sufficiently long time intervals, yields a richer assemblage than using line-transect methods, and faithfully records aspects of community structure; and second, these results imply that geochronologically well-constrained fossil cetacean assemblages might preserve ecologically relevant features of community structure, depending on depositional and taphonomic conditions.

coastline
cetacean stranding record
north pacific ocean
death assemblage


Fire and brief human occupations in Iberia during MIS 4: Evidence from Abric del Pastor (Alcoy, Spain)

Abstract: There is a relatively low amount of Middle Paleolithic sites in Europe dating to MIS 4. Of the few that exist, several of them lack evidence for anthropogenic fire, raising the question of how this period of global cooling may have affected the Neanderthal population. The Iberian Peninsula is a key area to explore this issue, as it has been considered as a glacial refugium during critical periods of the Neanderthal timeline and might therefore yield archaeological contexts in which we can explore possible changes in the behaviour and settlement patterns of Neanderthal groups during MIS 4. Here we report recent data from Abric del Pastor, a small rock shelter in Alcoy (Alicante, Spain) with a stratified deposit containing Middle Palaeolithic remains. We present absolute dates that frame the sequence within MIS 4 and multi-proxy geoarchaeological evidence of in situ anthropogenic fire, including microscopic evidence of in situ combustion residues and thermally altered sediment. We also present archaeostratigraphic evidence of recurrent, functionally diverse, brief human occupation of the rock shelter. Our results suggest that Neanderthals occupied the Central Mediterranean coast of the Iberian Peninsula during MIS 4, that these Neanderthals were not undergoing climatic stress and they were habitual fire users.


Environmental dynamics during the onset of the Middle Stone Age in eastern Africa

Abstract: The Middle Stone Age in Africa The Olorgesailie basin in the southern Kenya rift valley contains sediments dating back to 1.2 million years ago, preserving a long archaeological record of human activity and environmental conditions. Three papers present the oldest East African evidence of the Middle Stone Age (MSA) and elucidate the system of technology and behavior associated with the origin of Homo sapiens. Potts et al. present evidence for the demise of Acheulean technology that preceded the MSA and describe variations in late Acheulean hominin behavior that anticipate MSA characteristics. The transition to the MSA was accompanied by turnover of large mammals and large-scale landscape change. Brooks et al. establish that ∼320,000 to 305,000 years ago, the populations in eastern Africa underwent a technological shift upon procurement of distantly sourced obsidian for toolmaking, indicating the early development of social exchange. Deino et al. provide the chronological underpinning for these discoveries. Science, this issue p. 86, p. 90, p. 95 Changes in fauna, landscapes, and climate were associated with novel adaptive behaviors in the earliest Homo sapiens. Development of the African Middle Stone Age (MSA) before 300,000 years ago raises the question of how environmental change influenced the evolution of behaviors characteristic of early Homo sapiens. We used temporally well-constrained sedimentological and paleoenvironmental data to investigate environmental dynamics before and after the appearance of the early MSA in the Olorgesailie basin, Kenya. In contrast to the Acheulean archeological record in the same basin, MSA sites are associated with a markedly different faunal community, more pronounced erosion-deposition cycles, tectonic activity, and enhanced wet-dry variability. Aspects of Acheulean technology in this region imply that, as early as 615,000 years ago, greater stone material selectivity and wider resource procurement coincided with an increased pace of land-lake fluctuation, potentially anticipating the adaptability of MSA hominins.

middle stone age
eastern africa
environmental dynamic


Evenness and diversity in Upper Cambrian – Lower Ordovician trilobite communities from the Central Andean Basin (Cordillera Oriental, Argentina)

Abstract: Community evenness has recently received much attention, either because it is related to ecosystem functioning or because it may affect estimation of diversity. Temporal and environmental trends in diversity and evenness of trilobite communities during the Late Cambrian – Early Ordovician of the Cordillera Oriental (north‐western Argentina) are here analysed. Richness and evenness increase through time in both deep subtidal (between fair‐weather and storm wave base) and offshore (below storm wave base) communities. Two significant patterns are superimposed on this general trend: (1) the magnitude of the increase in evenness is much more pronounced in deep than in shallower settings, and (2) richness and evenness trajectories are decoupled (while a significant rise in evenness is recorded in the middle Tremadocian (Tr2), an increase in richness is delayed until the late Tremadocian (Tr3)). In contrast to expectations, a single family (Olenidae) is dominant in samples associated with this earlier rise in evenness relative to richness. Hence, this trend is explained neither by the number of families present in the communities nor by the familial identity of the most abundant taxon. Large‐scale comparisons of the timing and geographical components of these trends are restricted to the patterns recognized in Laurentian North American studies. Results from the Cordillera Oriental mirror those of Laurentia regarding the rise in both metrics in deep marine settings. Nevertheless, the timing of this increase in richness and evenness is delayed in the Cordillera Oriental, supporting the idea that palaeogeographical regions differed in the nature and timing of ecological changes. Finally, the rise in trilobite alpha‐diversity through the Late Cambrian – Early Ordovician of the Cordillera Oriental supports the idea that trilobite alpha‐diversity did not decline worldwide, suggesting that the relative decline in trilobite alpha‐diversity is most probably caused by the dilution effect.

trilobite community
cordillera oriental
evenness


New data from Oman indicate benthic high biomass productivity coupled with low taxonomic diversity in the aftermath of the Permian–Triassic Boundary mass extinction

Abstract: A new Early Triassic marine fauna is described from an exotic block (olistolith) from the Ad Daffah conglomerate in eastern Oman (Batain), which provides new insights into the ecology and diversity during the early aftermath of the Permian–Triassic Boundary mass extinction. Based on conodont quantitative biochronology, we assign a middle Griesbachian age to the upper part of this boulder. It was derived from an offshore seamount and yielded both nektonic and benthic faunas, including conodonts, ammonoids, gastropods and crinoid ossicles in mass abundance. This demonstrates that despite the stratigraphically near extinction at the Permian–Triassic Boundary, Crinoidea produced enough biomass to form crinoidal limestone as early as middle Griesbachian time. Baudicrinus, previously placed in Dadocrinidae, is now placed in Holocrinidae; therefore, Dadocrinidae are absent in the Early Triassic, and Holocrinidae remains the most basal crown-group articulates, originating during the middle Griesbachian in the Tethyan Realm. Abundant gastropods assigned to Naticopsis reached a shell size larger than 20 mm and provide another example against any generalized Lilliput effect during the Griesbachian. Whereas the benthic biomass was as high as to allow the resumption of small carbonate factories, the taxonomic diversity of the benthos remained low compared to post-Early Triassic times. This slow benthic taxonomic recovery is here attributed to low competition within impoverished post-extinction faunas.

oman
taxonomic diversity
aftermath
early triassic
griesbachian


The fragmentation of Pangaea and Mesozoic terrestrial vertebrate biodiversity

Abstract: During the Mesozoic (242–66 million years ago), terrestrial regions underwent a massive shift in their size, position and connectivity. At the beginning of the era, the land masses were joined into a single supercontinent called Pangaea. However, by the end of the Mesozoic, terrestrial regions had become highly fragmented, both owing to the drifting apart of the continental plates and the extremely high sea levels that flooded and divided many regions. How terrestrial biodiversity was affected by this fragmentation and large-scale flooding of the Earth's landmasses is uncertain. Based on a model using the species–area relationship (SAR), terrestrial vertebrate biodiversity would be expected to nearly double through the Mesozoic owing to continental fragmentation, despite a decrease of 24% in total terrestrial area. Previous studies of Mesozoic vertebrates have generally found increases in terrestrial diversity towards the end of the era, although these increases are often attributed to intrinsic or climatic factors. Instead, continental fragmentation over this time may largely explain any observed increase in terrestrial biodiversity. This study demonstrates the importance that non-intrinsic effects can have on the taxonomic success of a group, and the importance of geography to understanding past biodiversity.

pangaea
mesozoic
terrestrial vertebrate biodiversity
landmass


Effect of mass and habitat on the shape of limb long bones: A morpho‐functional investigation on Bovidae (Mammalia: Cetartiodactyla)

Abstract: Limb long bones are essential to an animal's locomotion, and are thus expected to be heavily influenced by factors such as mass or habitat. Because they are often the only organs preserved in the fossil record, understanding their adaptive trends is key to reconstructing the paleobiology of fossil taxa. In this regard, the Bovidae has always been a prized group of study. This family is extremely diverse in terms of both mass and habitat, and it is expected that their bones will possess adaptations to both factors. Here, we present the first 3D geometric morphometric study focusing on bovid limb long bones. We used anatomical landmarks as well as curve and surface sliding semi‐landmarks to accurately describe the stylopod and zeugopod bones. We included 50 species from ten of the twelve currently recognized tribes of bovids, ranging from 4.6 to 725 kg, and living in open plains, forests, mountains, or anywhere in‐between. Shape data were correlated with the mean mass of the species and its habitat, even when taking into account the phylogenetic history of our sample. Bones pertaining to heavy species are more robust, adapted for a better repartition of stronger forces. Articulations are especially affected, being proportionally much larger in heavier species. Muscle insertion areas are unevenly affected. Insertion areas of muscles implied in body support and propulsion show a strong increase in their robustness when compared to insertion areas of muscles acting on the limb mostly when it is off the ground. Habitat influences the shape of the humerus, the radius‐ulna, and the femur, but not of the tibia, whether the phylogeny is taken into account or not. Specific habitats tend to be associated with particular features on the bones. Articulations are proportionally wider in open‐habitat species, and the insertion areas of muscles involved in limb extension and propulsion are wider, reflecting the fact that open habitat species are more cursorial and rely on fast running to avoid predators. Forest and mountain species generally present similar adaptations for increased manoeuvrability, such as a round femoral head, and generally have more gracile bones.


Finding fossils in new ways: An artificial neural network approach to predicting the location of productive fossil localities

Abstract: Chance and serendipity have long played a role in the location of productive fossil localities by vertebrate paleontologists and paleoanthropologists. We offer an alternative approach, informed by methods borrowed from the geographic information sciences and using recent advances in computer science, to more efficiently predict where fossil localities might be found. Our model uses an artificial neural network (ANN) that is trained to recognize the spectral characteristics of known productive localities and other land cover classes, such as forest, wetlands, and scrubland, within a study area based on the analysis of remotely sensed (RS) imagery. Using these spectral signatures, the model then classifies other pixels throughout the study area. The results of the neural network classification can be examined and further manipulated within a geographic information systems (GIS) software package. While we have developed and tested this model on fossil mammal localities in deposits of Paleocene and Eocene age in the Great Divide Basin of southwestern Wyoming, a similar analytical approach can be easily applied to fossil‐bearing sedimentary deposits of any age in any part of the world. We suggest that new analytical tools and methods of the geographic sciences, including remote sensing and geographic information systems, are poised to greatly enrich paleoanthropological investigations, and that these new methods should be embraced by field workers in the search for, and geospatial analysis of, fossil primates and hominins. © 2011 Wiley‐Liss, Inc.

location
productive fossil locality
remote sensing


The terrestrial biota prior to the origin of land plants (embryophytes): a review of the evidence

Abstract: It is often assumed that life originated and diversified in the oceans prior to colonizing the land. However, environmental constraints in chemical evolution models point towards critical steps leading to the origin of life as having occurred in subaerial settings. The earliest fossil record does not include finds from terrestrial deposits, so much of our understanding about the presence of a terrestrial microbial cover prior to the Proterozoic is based on inference and geochemical proxies that indicate biospheric carbon cycling during the Archaean. Our assessment is that by 2.7 Ga, microbial ecosystems in terrestrial settings were driven by oxygen‐generating, photosynthetic cyanobacteria. Studies of modern organisms indicate that both the origin and primary diversification of the eukaryotes could have occurred in terrestrial settings, shortly after 2.0 Ga, but there is no direct fossil evidence of terrestrial eukaryotes until about 1.1 Ga. At this time, it appears that the diversity of life in non‐marine habitats exceeded that found in marine settings where sulphidic seas may have impaired eukaryotic physiology and retarded evolution. Geochemical proxies indicate the establishment of an extensive soil‐forming microbial cover by 850 Ma, and it is possible that a rise in atmospheric oxygen at this time was due to the evolutionary expansion of green algae into terrestrial habitats. Direct fossil evidence of the earliest terrestrial biotas in the Phanerozoic consists of problematical palynomorphs from the Cambro‐Ordovician of Laurentia. These indicate that the evolution of the first land plants (embryophytes) during the Middle Ordovician took place within a landscape that included aeroterrestrial algae which were actively adapting to selection in subaerial settings.


An early‐diverging procolophonid from the lowermost Triassic of South America and the origins of herbivory in Procolophonoidea

Abstract: Procolophonoidea was the only parareptile clade to survive the end‐Permian mass extinction, and they experienced a major adaptive radiation during the Triassic. The flourishing of procolophonoid lineages in highly stressful post‐extinction environments may be, at least in part, a result of their early adaptations to herbivory, which would eventually become the most common feeding strategy in later representatives of the group. Although procolophonoids are comparatively diverse in the South African Lystrosaurus declivis Assemblage Zone, only the Gondwanan widespread taxon Procolophon trigoniceps has been thus far reported in South American deposits of similar age. Here, we present a new procolophonid genus and species from the Lower Triassic Sanga do Cabral Formation of Brazil. Oryporan insolitus gen. et sp. nov. combines typical adaptations suggestive of herbivory with primitive character states that are peculiar to early procolophonoids. Accordingly, phylogenetic analysis places the new species as an early‐diverging procolophonid, thus far the phylogenetically earliest to develop apparent adaptations for herbivory. Character optimization shows that the bulbous, labiolingually expanded molariforms of most procolophonids (usually interpreted as indicative of high‐fibre herbivory) were co‐opted from an insectivorous dentition. The new taxon also highlights the diversity of feeding habits displayed by Early Triassic procolophonoids, which was probably crucial for the survival of the clade in post‐extinction disaster communities.

procolophonid
herbivory
procolophonoidea
phylogenetic analysis


Uncertain-tree: discriminating among competing approaches to the phylogenetic analysis of phenotype data

Abstract: Morphological data provide the only means of classifying the majority of life's history, but the choice between competing phylogenetic methods for the analysis of morphology is unclear. Traditionally, parsimony methods have been favoured but recent studies have shown that these approaches are less accurate than the Bayesian implementation of the Mk model. Here we expand on these findings in several ways: we assess the impact of tree shape and maximum-likelihood estimation using the Mk model, as well as analysing data composed of both binary and multistate characters. We find that all methods struggle to correctly resolve deep clades within asymmetric trees, and when analysing small character matrices. The Bayesian Mk model is the most accurate method for estimating topology, but with lower resolution than other methods. Equal weights parsimony is more accurate than implied weights parsimony, and maximum-likelihood estimation using the Mk model is the least accurate method. We conclude that the Bayesian implementation of the Mk model should be the default method for phylogenetic estimation from phenotype datasets, and we explore the implications of our simulations in reanalysing several empirical morphological character matrices. A consequence of our finding is that high levels of resolution or the ability to classify species or groups with much confidence should not be expected when using small datasets. It is now necessary to depart from the traditional parsimony paradigms of constructing character matrices, towards datasets constructed explicitly for Bayesian methods.

morphological data
phylogenetic method
bayesian implementation
simulation


“Without a leg to stand on”: on the evolution and development of axial elongation and limblessness in tetrapods

Abstract: A review of the osteology of the axial and appendicular skeleton of fossil and extant tetrapods, in the context of tetrapod phylogenetic patterns, reveals common patterns of limb loss and axial elongation. A threshold number of 35–40 presacral vertebrae is linked to minor reductions in digit number and the phalangeal count. Presacral vertebral counts do not increase gradually, rather, presacral counts jump from 35–40 to 60–70. At this point, limb loss is extreme, with forelimbs being reduced to tiny appendages or lost altogether. Higher presacral counts (>90) are linked to total forelimb loss and radical rear-limb reductions culminating in total loss. A pattern of this sort is recognized in Paleozoic lepospondyls and Mesozoic to modern squamates. Developmental genetic models illuminate gene systems that are associated with morphogenesis and are linked to the evolution of limb reduction and leglessness in these tetrapods.


Orbitally paced paleoproductivity variations in the Timor Sea and Indonesian Throughflow variability during the last 460 kyr

Abstract: [1] A high-resolution (∼1–2 kyr) multiproxy record from the Timor Sea in the easternmost Indian Ocean (International Marine Global Change (IMAGES) Program Core MD01-2378, latitude 13°04.95′S, longitude 121°47.27′E, 1783 m water depth) closely tracks changes in intermediate water ventilation and paleoproductivity over the last 460 kyr within one of the main outflow passages of the Indonesian Throughflow. Spectral analysis of five different flux-based productivity proxies indicates spectral power concentrated in the 100 kyr (glacial-interglacial) and the 23 kyr and 19 kyr (precessional) periods. Paleoproductivity maxima lead ice volume (benthic δ18O) maxima by 20° to 40° (∼1300 to 2600 years) at the precession band. The spectral differences in tropical paleoproductivity records from the Pacific and Indian oceans suggest that local processes (wind and circulation patterns driven by insolation) are dominant in driving productivity rather than large-scale tropical features. In the Timor Sea, productivity fluctuations over the last 460 kyr were strongly influenced by monsoonal wind patterns offshore NW Australia (23 and 19 kyr) and were also modulated by sea level–related variations in the intensity of the Indonesian Throughflow (100 kyr).

timor sea
indian ocean
insolation
monsoonal wind pattern


Linear and Geometric Morphometric Analysis of Long Bone Scaling Patterns in Jurassic Neosauropod Dinosaurs: Their Functional and Paleobiological Implications

Abstract: Neosauropod dinosaurs were gigantic, herbivorous dinosaurs. Given that the limb skeleton is essentially a plastic, mobile framework that supports and moves the body, analysis of long bone scaling can reveal limb adaptations that supported neosauropod gigantism. Previously, analyses of linear dimensions have revealed a relatively isometric scaling pattern for the humerus and femur of neosauropods. Here, a combined scaling analysis of humerus and femur linear dimensions, cortical area, and shape across six neosauropod taxa is used to test the hypothesis that neosauropod long bones scaled isometrically and to investigate the paleobiological implications of these trends. A combination of linear regression and geometric morphometrics analyses of neosauropod humeri and femora were performed using traditional and thin‐plate splines approaches. The neosauropod sample was very homogeneous, and linear analyses revealed that nearly all humerus and femur dimensions, including cortical area, scale with isometry against maximum length. Thin‐plate splines analyses showed that little to no significant shape change occurs with increasing length or cortical area for the humerus or femur. Even with the exclusion of the long‐limbed Brachiosaurus, the overall trends were consistently isometric. These results suggest that the mechanical advantage of limb‐moving muscles and the relative range of limb movement decreased with increasing size. The isometric signal for neosauropod long bone dimensions and shape suggests these dinosaurs may have reached the upper limit of vertebrate long bone mechanics. Perhaps, like stilt‐walkers, the absolutely long limbs of the largest neosauropods allowed for efficient locomotion at gigantic size with few ontogenetic changes. Anat Rec, 290:1089–1111, 2007. © 2007 Wiley‐Liss, Inc.

geometric morphometric analysis
long bone
dimension


The eruptive tempo of Deccan volcanism in relation to the Cretaceous-Paleogene boundary

Abstract: Two timelines for extinction The Cretaceous-Paleogene extinction that wiped out the nonavian dinosaurs 66 million years ago was correlated with two extreme events: The Chicxulub impact occurred at roughly the same time that massive amounts of lava were erupting from the Deccan Traps (see the Perspective by Burgess). Sprain et al. used argon-argon dating of the volcanic ash from the Deccan Traps to argue that a steady eruption of the flood basalts mostly occurred after the Chicxulub impact. Schoene et al. used uranium-lead dating of zircons from ash beds and concluded that four large magmatic pulses occurred during the flood basalt eruption, the first of which preceded the Chicxulub impact. Whatever the correct ordering of events, better constraints on the timing and rates of the eruption will help elucidate how volcanic gas influenced climate. Science, this issue p. 866, p. 862; see also p. 815 The large impact associated with the demise of nonavian dinosaurs may have preceded the eruption of vast amounts of magma. Late Cretaceous records of environmental change suggest that Deccan Traps (DT) volcanism contributed to the Cretaceous-Paleogene boundary (KPB) ecosystem crisis. However, testing this hypothesis requires identification of the KPB in the DT. We constrain the location of the KPB with high-precision argon-40/argon-39 data to be coincident with changes in the magmatic plumbing system. We also found that the DT did not erupt in three discrete large pulses and that >90% of DT volume erupted in <1 million years, with ~75% emplaced post-KPB. Late Cretaceous records of climate change coincide temporally with the eruption of the smallest DT phases, suggesting that either the release of climate-modifying gases is not directly related to eruptive volume or DT volcanism was not the source of Late Cretaceous climate change.

eruption
volcanism
cretaceous-paleogene boundary


Magnification and resolution in dental microwear analysis using light microscopy

Abstract: One potentially problematic aspect of dental microwear analysis is sensitivity to the resolution (fineness of detail) at which dental wear surfaces are viewed. Magnification is one of many variables that determine resolution. Microwear studies based on light microscopy generally report magnifications ranging from 30X-100X, although ambiguities in reported methods prohibit duplication of the resolutions of many studies. Moreover, magnification settings have been arbitrary and, thus far, the biasing effects of different resolutions have not been tested. We tested sensitivity of dental microwear analysis to resolution by manipulating pixel density and magnification in photomicrographs taken under a light microscope using the molars of a browser (moose), grazer (zebra), and frugivore/hard object feeder (peccary). Resolution affected the number of observable microwear features and distorted the proportional frequencies of large and small features. Nonetheless, two observers independently found similar differences between the species throughout a range of resolutions. At no resolution did observers recover statistically undifferentiated data, although interobserver correlation was best when resolution was decreased to 20-40% of the initial resolution. Observer correlation for microwear features with a maximal dimension >20 μm was substantially better than for smaller features. We conclude that (1) dimensionless aspects of microwear data (e.g., proportional numbers of scratches between species) are more robust to resolution than raw frequency data, (2) higher resolution does not produce higher quality data, and (3) the optimal resolution may be dependent upon the size of the microwear features. Further testing of the interaction of resolution, microwear feature size, and the observer will increase repeatability of results and lead to more robust paleodietary interpretations.

resolution
dental microwear analysis
light microscopy
scratch


Gavialis from the Pleistocene of Thailand and Its Relevance for Drainage Connections from India to Java

Abstract: Background The genus Gavialis comprises a single living but endangered species, G. gangeticus, as well as fossil species recorded in the Miocene to Pleistocene deposits of the Indian subcontinent. The genus is also represented in the Pleistocene deposits of Java by the species G. bengawanicus, which was recently recognized to be valid. Surprisingly, no detailed report of the genus exists between these two provinces and the recent evolutionary history of Gavialis is not understood. Methodology/Principal Findings We report new material consisting of skull and mandibular remains of Gavialis from the Early Pleistocene of Khok Sung, Nakhon Ratchasima Province, northeastern Thailand. The Gavialis material described herein is attributed to Gavialis cf. bengawanicus and sheds new light on the occurrence of the genus in mainland SE Asia. Conclusions/Significance Comparison of this new material with other species referred to the genus Gavialis led us to preliminary restrict the content of the genus to three species, namely G. gangeticus Gmelin, G. bengawanicus Dubois and G. lewisi Lull. The occurrence of G. cf. bengawanicus in Thailand allows us to propose a scenario for the dispersal of Gavialis from Indo-Pakistan to Indonesia, thus bridging a geographical gap between these two provinces. Dispersal by sea appears a less likely possibility than dispersal through fluvial drainages.


Cladistic analysis of Caseidae (Caseasauria, Synapsida): using the gap‐weighting method to include taxa based on incomplete specimens

Abstract: Occupying the role of primary consumer and having an early–middle Permian age range, caseids (Caseasauria, Synapsida) are fundamental to the interpretation of the early history of terrestrial vertebrate ecosystems. Despite this importance, no comprehensive, species‐level phylogenetic study of Caseidae has yet been performed. Herein, we present a phylogenetic analysis of the group, using gap weighting to include poorly known taxa. Besides the description and comments on the resultant topologies, some more general issues concerning cladistic methodologies are briefly addressed. This study highlights the importance of a total‐evidence approach, including as many within‐group taxa and characters as possible. Continuously varying characters, in the form of indices derived from measurement of individual skeletal elements, proved to be highly important, adding significantly to the resolution of, and support for, recovered trees. The utility of the postcranial skeleton in understanding relationships among basal synapsids is highlighted.


Exhaustive sample set among Viverridae reveals the sister-group of felids: the linsangs as a case of extreme morphological convergence within Feliformia

Abstract: Although molecular studies have helped to clarify the phylogeny of the problematic family Viverridae, a recent phylogenetic investigation based on cytochrome b (cyt b) has excluded the Asiatic linsangs (genus Prionodon) from the family. To assess the phylogenetic position of the Asiatic linsangs within the Feliformia, we analysed an exhaustive taxonomic sample set with cyt b and newly produced transthyretin intron I sequences (TR–I–I). TR–I–I alone and cyt b+TR–I–I combined (maximum–likelihood analysis) highly support the position of Asiatic linsangs as sister–group of the Felidae. The estimation of minimum divergence dates from molecular data suggests a splitting event ca. 33.3 million years (Myr) ago, which lends support to historical assertions that the Asiatic linsangs are ‘living fossils’ that share a plesiomorphic morphotype with the Oligocene feliform Paleoprionodon. The African linsang is estimated to appear more than 20 Myr later and represents the sister–group of the genus Genetta. Our phylogenetic results illustrate numerous morphological convergences of ‘diagnostic’ characters among Feliformia that might be problematic for the identification of fossil taxa. The morphotype reappearance from the Asiatic to the African linsangs suggests that the genome of the Feliformia conserved its potential ability of expression for a peculiar adaptive phenotype throughout evolution, in this case arboreality and hypercarnivory in tropical forest.

viverridae
morphological convergence
feliformia
molecular data


Observations on surface ornamentation in fossil Ostracoda

Abstract: It has recently been demonstrated (Okada, 1982) that some reticulate Ostracoda develop ornamentation by a process which reflects the arrangement of underlying epidermal cells. Pitting and secondary reticulation are also characteristic of many such forms, either during ontogeny or phylogeny, and as these features are of lesser dimensions than epidermal cells, a process at variance with that described by Okada must be responsible for their production. Outlined below is evidence from fossil Ostracoda supporting the hypothesis that actual valve resorption may occur during ontogeny to produce these second order features.

ornamentation
fossil ostracoda
ostracod carapace


More than 100 years of a mistake: on the anatomy of the atlas of the enigmatic Macrauchenia patachonica

Abstract: Ever since the discovery of the first remains of Macrauchenia patachonica by Charles Darwin in 1834, this taxon has puzzled researchers with its peculiar anatomy. Being the best-known member of the family Macraucheniidae and with fossil records in extensive areas of South America between the Middle to Late Pleistocene/earliest Holocene, M. patachonica has been extensively studied over decades, and recently even included in molecular studies. However, there are some elements of its skeleton that have been inadvertently unstudied. One of these elements is the atlas of M. patachonica that due to a misidentification made 159 years ago by the prominent zoologist Hermann Burmeister, was not examined or illustrated by later researchers even with access to excellent specimens. Here, we describe and illustrate the atlas of M. patachonica for the first time, correcting Burmeister's mistake. Overall, the anatomy of the atlas of M. patachonica is consistent with the anatomy of older macraucheniids. The atlas described by Burmeister as being M. patachonica probably corresponds to that of a bovid. It is noteworthy that most mounted skeletons of M. patachonica present today in museum exhibitions, display a correct atlas derived from a more complete specimen discovered ca. 1904 by the prominent palaeontologist Santiago Roth.

mistake
anatomy
macrauchenia patachonica
pleistocene


Mammal community structure correlates with arboreal heterogeneity in faunally and geographically diverse habitats: implications for community convergence

Abstract:
Aim  To quantify how mammal community structure relates to heterogeneity of vegetation for palaeoecological reconstructions, and to test whether historical or environmental factors are more important in structuring communities.

Location  Sixty-three natural protected areas in Asia, Africa and South and Central America.

Methods  We defined faunal communities by allocating species to ecological guilds and calculating proportional representation within each guild. Vegetation heterogeneity for each natural protected area was calculated from satellite images. The relationship between these ecospaces was calculated using canonical correlations analysis, redundancy analysis and principal components analysis. We expected that large, herbivorous mammals would be most strongly correlated with open areas. Convergence was tested by independently eliminating the effects of geography and vegetation heterogeneity on the structure of the mammal communities. We expected that vegetation would more strongly structure communities than geographical position.

Results  We show that the guild structure of communities across habitats is significantly correlated with vegetation heterogeneity. The highest correlation was between small, scansorial-arboreal secondary consumers and heavy tree cover. The first convergence analysis shows American communities distinguished from Asian and African communities; these latter communities show a remarkable convergence in structure. Historical factors only affected the continent whose mammals had experienced a long period of isolation. The second convergence analysis shows that almost all biomes have the same or very similar community structure regardless of continent.

Main conclusions  Communities from the same environments in different continents showed remarkable convergence. Communities from the same continents only converged when those continents shared a recent geological and biological history. These results suggest that historical and environmental factors are operating over different timescales. This study confirms that environmental reconstructions made on the basis of whole communities will accurately reflect the environment that the community lived in. However, reconstructions made for fossil sites in deep time need to take historical factors into consideration. Small, arboreal and scansorial secondary consumers show the strongest correlation with vegetation, correlating with continuous tree canopy cover. This relationship allows simple reconstructions of the amount of tree cover occurring in a landscape from the proportion of species from the community falling in this ecological guild.

heterogeneity
palaeoecological reconstruction
mammal community structure


Exploring adaptive landscapes across deep time: A case study using echinoid body size

Abstract: Adaptive landscapes are a common way of conceptualizing the phenotypic evolution of lineages across deep time. Although multiple approaches exist to implement this concept into operational models of trait evolution, inferring adaptive landscapes from comparative datasets remains challenging. Here, I explore the macroevolutionary dynamics of echinoid body size using data from over 5000 specimens and a phylogenetic framework incorporating a dense fossil sampling and spanning approximately 270 million years. Furthermore, I implement a novel approach of exploring alternative parameterizations of adaptive landscapes that succeeds in finding simpler, yet better‐fitting models. Echinoid body size has been constrained to evolve within a single adaptive optimum for much of the clade's history. However, most of the morphological disparity of echinoids was generated by multiple regime shifts that drove the repeated evolution of miniaturized and gigantic forms. Events of body size innovation occurred predominantly in the Late Cretaceous and were followed by a drastic slowdown following the Cretaceous‐Paleogene mass extinction. The discovery of these patterns is contingent upon directly sampling fossil taxa. The macroevolution of echinoid body size is therefore characterized by a late increase in disparity (likely linked to an expansion of ecospace), generated by active processes driving lineages toward extreme morphologies.

adaptive landscape
deep time
echinoid body size
macroevolutionary dynamic


Amazonia Through Time: Andean Uplift, Climate Change, Landscape Evolution, and Biodiversity

Abstract: The Making of Amazonian Diversity The biodiversity of the Amazon Basin is legendary, but the processes by which it has been generated have been debated. In the late 20th century the prevalent view was that the engine of diversity was repeated contraction and expansion of forest refugia during the past 3 million years or so. Hoorn et al. (p. 927) analyze findings from a diverse range of disciplines, including molecular phylogeny, ecology, sedimentology, structural geology, and palaeontology, to offer an overview of the entire history of this region during the Cenozoic era (66 million years ago). The uplift of the Andes was a pivotal event in the evolution of Amazonian landscapes because it continually altered river drainage patterns, which in turn put a variety of pressures on organisms to adapt to changing conditions in a multiplicity of ways. Hence, the diversity of the modern biota of the Amazon has more ancient origins than previously thought. The Amazonian rainforest is arguably the most species-rich terrestrial ecosystem in the world, yet the timing of the origin and evolutionary causes of this diversity are a matter of debate. We review the geologic and phylogenetic evidence from Amazonia and compare it with uplift records from the Andes. This uplift and its effect on regional climate fundamentally changed the Amazonian landscape by reconfiguring drainage patterns and creating a vast influx of sediments into the basin. On this “Andean” substrate, a region-wide edaphic mosaic developed that became extremely rich in species, particularly in Western Amazonia. We show that Andean uplift was crucial for the evolution of Amazonian landscapes and ecosystems, and that current biodiversity patterns are rooted deep in the pre-Quaternary.

andean uplift
biodiversity
amazonia
gondwanan landmass
marine transgression


Dinoflagellate cyst assemblages as tracers of sea‐surface conditions in the northern North Atlantic, Arctic and sub‐Arctic seas: the new ‘n = 677’ data base and its application for quantitative palaeoceanographic reconstruction

Abstract: The distribution of dinoflagellate cyst (dinocyst) assemblages in surface sediment samples from 677 sites of the northern North Atlantic, Arctic and sub‐Arctic seas is discussed with emphasis on the relationships with sea‐surface parameters, including sea‐ice cover, salinity and temperature of the coldest and warmest months. Difficulties in developing a circum‐Arctic data base include the morphological variation within taxa (e.g. Operculodinium centrocarpum, Islandinium? cezare and Polykrikos sp.), which probably relate to phenotypic adaptations to cold and/or low salinity environments. Sparse hydrographical data, together with large interannual variations of temperature and salinity in surface waters of Arctic seas constitute additional limitations. Nevertheless, the use of the best‐analogue technique with this new dinocyst data base including 677 samples permits quantitative reconstruction of sea‐surface conditions at the scale of the northern North Atlantic and the Arctic domain. The error of prediction calculated from modern assemblages is ±1.3 °C and ±1.8 °C for the temperature of February and August, respectively, ±1.8 for the salinity, and ±1.5 months yr−1 for the sea‐ice cover. Application to late Quaternary sequences from the western and eastern subpolar North Atlantic (Labrador Sea and Barents Sea) provide reconstructions compatible with those obtained using the previous dinocyst data base (n = 371), which mainly included modern data from the northern North Atlantic. Copyright © 2001 John Wiley & Sons, Ltd.

cyst
northern north atlantic
sub‐arctic sea


New carnivoraforms (Mammalia) from the middle Eocene of California, USA, and comments on the taxonomic status of 'Miacis' gracilis

Abstract: The middle Eocene constitutes an important period for understanding the early evolution of carnivoraforms and the origin of crown-group carnivorans. Here I describe two new genera of carnivoraforms from the Uintan North American Land Mammal Age of southern California, and report hitherto-undescribed specimens of Procynodictis progressus, 'Miacis' gracilis, 'Miacis' hookwayi, and two undeterminate taxa to bridge some of the gaps in taxonomic knowledge. Specifically, the fossil materials described here support the placement of P. vulpiceps and P. progressus in the same genus but suggest their distinct identities at the species level. Similarly, 'M.' gracilis, which has been synonymized with P. vulpiceps by some authors, is considered a separate species from both P. vulpiceps and P. progressus. A minimum of 11 carnivoraform taxa are recognized in the middle Eocene of southern California, including nine from the late Uintan to the earliest Duchesnean (ca. 43-41 Ma ago). Of the latter, at least six taxa are apparently endemic to this region, thus conforming to the high provinciality of North American mammalian faunas during this time. In addition to the carnivoraforms, four taxa of creodonts and a mesonychid are known. The notably high taxonomic richness of middle-Eocene mammalian carnivores in southern California is associated with high diversity of non-carnivorous mammals known from there; this pattern agrees with the correlation between mammalian predator and prey diversity that has previously been observed at various spatiotemporal scales. The stratigraphic distributions of the late-Uintan taxa reported here are consistent with the recently revised ages of vertebrate assemblages from the Sespe Formation of Ventura County, California, in the parsimonious sense.


The evolutionary convergence of mid-Mesozoic lacewings and Cenozoic butterflies

Abstract: Mid-Mesozoic kalligrammatid lacewings (Neuroptera) entered the fossil record 165 million years ago (Ma) and disappeared 45 Ma later. Extant papilionoid butterflies (Lepidoptera) probably originated 80–70 Ma, long after kalligrammatids became extinct. Although poor preservation of kalligrammatid fossils previously prevented their detailed morphological and ecological characterization, we examine new, well-preserved, kalligrammatid fossils from Middle Jurassic and Early Cretaceous sites in northeastern China to unravel a surprising array of similar morphological and ecological features in these two, unrelated clades. We used polarized light and epifluorescence photography, SEM imaging, energy dispersive spectrometry and time-of-flight secondary ion mass spectrometry to examine kalligrammatid fossils and their environment. We mapped the evolution of specific traits onto a kalligrammatid phylogeny and discovered that these extinct lacewings convergently evolved wing eyespots that possibly contained melanin, and wing scales, elongate tubular proboscides, similar feeding styles, and seed–plant associations, similar to butterflies. Long-proboscid kalligrammatid lacewings lived in ecosystems with gymnosperm–insect relationships and likely accessed bennettitalean pollination drops and pollen. This system later was replaced by mid-Cretaceous angiosperms and their insect pollinators.

lacewing
butterfly
kalligrammatid lacewing
northeastern china


New Saber-Toothed Cat Records (Felidae: Machairodontinae) for the Pleistocene of Venezuela, and the Great American Biotic Interchange

Abstract:
ABSTRACT
 The Machairodontinae fossil record in South America is not very diverse. Until now, only the genus Smilodon (Smilodontini) has been reported, with likely a single species, S. populator. A second taxon of Machairodontinae was referred to Homotheriini and to the genus Xenosmilus, but the age to which it was assigned, early to middle Pleistocene, is uncertain, because it was recovered out of stratigraphic context. At present, the Venezuelan saber-toothed cat record is limited to the late Pleistocene, and consists of fossils found in Mene de Inciarte (state of Zulia), and from Zumbador cave deposit in the state of Falcón. Here we report a new species of Machairodontinae Homotherium venezuelensis, nov. sp., as well as the first record of Smilodon gracilis in South America. Both were found in El Breal de Orocual, a tar seep in the state of Monagas, northeastern Venezuela. The age of the deposit has been interpreted as early to middle Pleistocene by thermoluminescence dating. We have been able to identify 30 vertebrate taxa, suggesting a paleoenvironment similar to the Venezuelan llanos today: an extensive savanna with rivers and patches of gallery forest. The saber-toothed cats described here demonstrate that the biogeography of Neotropical felids is more complex than previously thought, and allow us to identify new invasions and delimit the times during which they occurred. The fossils from Orocual represent the first record of Homotherium for South America, indicating that scimitar-toothed cats invaded this continent as early as the early—middle Pleistocene.


A Historical Overview of the Classification, Evolution, and Dispersion of Leishmania Parasites and Sandflies

Abstract: Background The aim of this study is to describe the major evolutionary historical events among Leishmania, sandflies, and the associated animal reservoirs in detail, in accordance with the geographical evolution of the Earth, which has not been previously discussed on a large scale. Methodology and Principal Findings Leishmania and sandfly classification has always been a controversial matter, and the increasing number of species currently described further complicates this issue. Despite several hypotheses on the origin, evolution, and distribution of Leishmania and sandflies in the Old and New World, no consistent agreement exists regarding dissemination of the actors that play roles in leishmaniasis. For this purpose, we present here three centuries of research on sandflies and Leishmania descriptions, as well as a complete description of Leishmania and sandfly fossils and the emergence date of each Leishmania and sandfly group during different geographical periods, from 550 million years ago until now. We discuss critically the different approaches that were used for Leishmana and sandfly classification and their synonymies, proposing an updated classification for each species of Leishmania and sandfly. We update information on the current distribution and dispersion of different species of Leishmania (53), sandflies (more than 800 at genus or subgenus level), and animal reservoirs in each of the following geographical ecozones: Palearctic, Nearctic, Neotropic, Afrotropical, Oriental, Malagasy, and Australian. We propose an updated list of the potential and proven sandfly vectors for each Leishmania species in the Old and New World. Finally, we address a classical question about digenetic Leishmania evolution: which was the first host, a vertebrate or an invertebrate? Conclusions and Significance We propose an updated view of events that have played important roles in the geographical dispersion of sandflies, in relation to both the Leishmania species they transmit and the animal reservoirs of the parasites.

classification dispersion sandfly leishmaniasis trypanosomatidae


Ancient pinnate leaf mimesis among lacewings

Abstract: Insects have evolved diverse methods of predator avoidance, many of which implicate complex adaptations of their wings (e.g., Phylliidae, Nymphalidae, Notodontidae). Among these, angiosperm leaf mimicry is one of the most dramatic, although the historical origins of such modifications are unclear owing to a dearth of paleontological records. Here, we report evidence of pinnate leaf mimesis in two lacewings (Neuroptera): Bellinympha filicifolia Y. Wang, Ren, Liu & Engel gen. et sp. nov. and Bellinympha dancei Y. Wang, Ren, Shih & Engel, sp. nov., from the Middle Jurassic, representing a 165-million-year-old specialization between insects and contemporaneous gymnosperms of the Cycadales or Bennettitales. Furthermore, such lacewings demonstrate a preangiosperm origin for leaf mimesis, revealing a lost evolutionary scenario of interactions between insects and gymnosperms. The current fossil record suggests that this enigmatic lineage became extinct during the Early Cretaceous, apparently closely correlated with the decline of Cycadales and Bennettitales at that time, and perhaps owing to the changing floral environment resulted from the rise of flowering plants.


A method for improved identification of postcrania from mammalian fossil assemblages: multivariate discriminant function analysis of camelid astragali

Abstract: Character-rich craniodental specimens are often the best material for identifying mammalian fossils to the genus or species level, but what can be done with the many assemblages that consist primarily of dissociated postcrania? In localities lacking typically diagnostic remains, accurate identification of postcranial material can improve measures of mammalian diversity for wider-scale studies. Astragali, in particular, are often well-preserved and have been shown to have diagnostic utility in artiodactyls. The Thousand Creek fauna of Nevada (~8 Ma) represents one such assemblage rich in postcranial material but with unknown diversity of many taxa, including camelids. We use discriminant function analysis (DFA) of eight linear measurements on the astragali of contemporaneous camelids with known taxonomic affinity to produce a training set that can then be used to assign taxa to the Thousand Creek camelid material. The discriminant function identifies, at minimum, four classes of camels: "Hemiauchenia", Alforjas, Procamelus, and ?Megatylopus. Adding more specimens to the training set may improve certainty and accuracy for future work, including identification of camelids in other faunas of similar age. For best statistical practice and ease of future use, we recommend using DFA rather than qualitative analyses of biplots to separate and diagnose taxa.

postcrania
discriminant function analysis
astragali


GLIRIDAE (RODENTIA, MAMMALIA) FROM THE LATE MIOCENE FISSURE FILLING BIANCONE 1 (GARGANO, PROVINCE OF FOGGIA, ITALY)

Abstract: Two new species of the endemic genus Stertomys (Mammalia, Rodentia, Gliridae) are described from the Late Miocene fissure filling Biancone 1 on the palaeoisland Gargano (Province of Foggia, Italy): S. daamsi and S. daunius. A third new species, Dryomys apulus, presents no endemic features at the generic level and is assigned to the extant genus Dryomys. The new taxa suggest that faunal immigration to Gargano occurred in one event, and that the Biancone deposit is, at most, Late Miocene in age. Additionally, an analysis of all fossil Myomiminae argues that Stertomys belongs to that subfamily, and that it may be derived from Myomimus dehmi or Miodyromys aegercii.


Loess in the Vojvodina region (Northern Serbia): an essential link between European and Asian Pleistocene environments

Abstract: Abstract Loess deposits in the Vojvodina region, northern Serbia, are among the oldest and most complete loess-paleosol sequences in Europe to date. These thick sequences contain a detailed paleoclimatic record from the late Early Pleistocene. Based on the correlation of detailed magnetic susceptibility (MS) records from Vojvodina with the Chinese loess record and deep-sea isotope stratigraphy we here reconfirm and expand on a stratigraphic model of the Vojvodinian loess-paleosol chronostratigraphic sequence following the Chinese loess stratigraphic system. Variations in MS, dust accumulation rates, and the intensity of pedogenesis demonstrate evidence for a Middle Pleistocene climatic and environmental transition. The onset of loess deposition in Vojvodina also indicates a direct link between dust generation in Europe and that in the interior of Eurasia since the Early Pleistocene. The youngest part of the Early Pleistocene and oldest part of the Middle Pleistocene is characterised by relatively uniform dust accumulation and soil formation rates as well as relatively high magnetic susceptibility values. In contrast, the last five interglacial-glacial cycles are characterised by sharp environmental differences between high dust accumulation rates during the glacials and low rates observed during soil development. The data presented in this study demonstrate the great potential of Vovjodina's loess archives for accurate reconstruction of continental Eurasian Pleistocene climatic and environmental evolution.


Statoliths from the Jurassic succession of south-west England, United Kingdom

Abstract: The occurrence of statoliths within the Jurassic succession of south-west England and other parts of Europe is reviewed. Five 'morphospecies' have been identified, ranging in age from Hettangian to Kimmeridgian. With so little published information on statoliths, the presently known geological record is incomplete, although new occurrences are continually being discovered. The occurrence of statoliths, in the absence of soft-bodied fossils, may ultimately provide a more complete indication of the distribution of the soft-bodied host animals. At the present time, however, only one of the statolith 'morphospecies' can be, tentatively, linked to a known species of teuthid.

jurassic succession
south-west england
statolith


Triassic coleoid beaks and other structures
from the Calcareous Alps revisited

Abstract: A. 2022. Triassic coleoid beaks and other structures from the Calcareous Alps. Acta Palaeontologica Polonica 67 (X): xxx–xxx. We performed comprehensive study of seven Carnian, Late Triassic specimens of a coleoid cephalopod Phragmoteuthis bisinuata , on which Suess based his hypothesis on “beaks of P. bisinuata ”. Using SEM/EDS, we found that “beaks of P. bisinuata ” consist of a micro-granular carbonized matrix containing ~4–30 μm diameter and ~50–200 μm visible length, dense calcified bone-like micro-structures. This strongly suggests that these objects are vertebrate bone-inducing cartilages in which the matrix was post-mortem reworked by carbon-accumulating bacteria and substituted by nano-particles of carbon accumulated in micro-granules. Hence, the presumed “beaks of P. bisinuata ” are cartilaginous remains of a prey, presum-ably juvenile fish. This data dismissed the entire hypothesis of Seuss. A small spatula-shape plate with a rachis-like process in an association with 10 or so imprints around (arm crown), found in front of a proostracum of P. bisinuata evidences an unknown Late Triassic juvenile teuthid which possessed a gladius resembling that of the early Permian Glochinomorpha stifeli. It inhabited the open sea area of the northwestern Tethys Ocean, and was, along with juvenile fishes, in the diet of P. bisinuata . The first identified Anisian (Middle Triassic) coleoid beak is represented by an isolated specimen from the Gardena Valley, NE Italy. It has a typical composition and morphology of coleoid upper beak: chitinous, wide-oval lateral walls, short wings, and pointed hook-like rostrum. This suggests similar upper beak structure in the Carnian P. bisinuata in which the lower beaks were apparently similar to that of the co-occurring Lunzoteuthis schindelbergensis and had a widely open outer lamella with posteriorly elongated paired wings joined into a pointed rostrum in the anterior portion.

calcareous alps
proostracum
triassic coleoid beak


The significance of Anomalocaris and other Radiodonta for understanding paleoecology and evolution during the Cambrian explosion

Abstract: One of the most widespread and diverse animal groups of the Cambrian Explosion is a clade of stem lineage arthropods known as Radiodonta, which lived exclusively in the early Paleozoic. First reported in 1892 with Anomalocaris canadensis, radiodonts are now one of the best known early animal groups with excellent representation in the fossil record, and are ubiquitous components of Konservat-Lagerstätten from the Cambrian and the Early Ordovician. These large swimmers were characterised by a segmented body bearing laterally-oriented flaps, and a head with a distinct radial oral cone, a pair of large frontal appendages adapted for different feeding modes, compound eyes on stalks, and prominent head carapaces. Radiodonts inform on the paleoecology of early animal communities and the steps involved in euarthropod evolution. Four families within Radiodonta have been established. The raptorial predator families Anomalocarididae and Amplectobeluidae were dominant early in the evolutionary history of Radiodonta, but were later overtaken by the mega-diverse and widespread Hurdiidae, which has a more generalised sediment-sifting predatory mode. Suspension feeding, notably in the families Tamisiocarididae and Hurdiidae, also evolved at least twice in the history of the clade. The well-preserved anatomical features of the radiodont body and head have also provided insights into the evolution of characteristic features of Euarthropoda, such as the biramous limbs, compound eyes, and organisation of the head. With 37 species recovered from all major paleocontinents of the Cambrian and Early Ordovician, Radiodonta provides a unique opportunity for revealing evolutionary patterns during the Cambrian Explosion.

radiodonta
paleoecology
cambrian explosion
oral cone


Is predation intensity reduced with increasing depth? Evidence from the west Atlantic stalked crinoid Endoxocrinus parrae (Gervais) and implications for the Mesozoic marine revolution

Abstract: The number of regenerated arms was counted on specimens of two distinct phenotypes of the stalked crinoid Endoxocrinus parrae (Gervais) from a wide bathymetric range in the Caribbean (178-723 m). In one phenotype, the sample was divided into two groups, one from shallower (< 500 m) depths, the other from deeper (≥ 500 m); in the other phenotype the group divided at 550 m. In both phenotypes, the frequency of regenerated arms is significantly higher in specimens from shallower water than in those from deeper water. If the regenerated arms in Endoxocrinus parrae were the result of sublethal predation, as previously suggested, then predation intensity is higher in shallow water than deep water. These results are consistent with the idea of the late Mesozoic marine revolution—that there has been stronger predation on various invertebrates in shallow-water environments since the late Mesozoic. The stalked crinoids may have been unable to cope with increased predation in shelf environments, and they migrated to offshore environments.


Tarimspira from the Cambrian (Series 2, Stage 4) of Laurentia (Greenland): extending the skeletal record of paraconodontid vertebrates

Abstract: Abstract. Phosphatic sclerites of the problematic Tarimspira Yue and Gao, 1992 (Cambrian Series 2) recovered by weak acid maceration of limestones display a unique range of mainly strongly coiled morphologies. They were likely organized into multielement scleritomes, but the nature of these is poorly known; some sclerites may have had a grasping function. Tarimspira sclerites grew by basal accretion in an analogous fashion to younger paraconodonts (Cambrian Series 3–4) but lack a basal cavity. Based on proposed homologies, Tarimspira may provide an extension of the early vertebrate paraconodont–euconodont clade back into the early Cambrian. Tarimspira is described for the first time from Laurentia (North Greenland), extending its known range from China and Siberia in Cambrian Series 2. In addition to the type species, Tarimspira plana Yue and Gao, 1992, the Greenland record of Tarimspira includes two morphotypes of a new species, Tarimspira artemi.


The first record of Ascaridoidea eggs discovered in Crocodyliformes hosts from the Upper Cretaceous of Brazil

Abstract: A paleoparasitological investigation was carried out on Crocodyliformes coprolites discovered in the Municipality of Santo Anastacio, in the southwestern region of the State of Sao Paulo. Individual samples were extracted from the surface and internal portion of each coprolite which revealed the presence of thick-shelled parasite eggs in three of them. The morphological characteristics of the specimens, i.e., rounded or oval shape, thick-shelled with mammillated surface, as well as their size, suggest that these eggs belong to the superfamily Ascaridoidea, which are gastrointestinal parasite nematodes of vertebrates, popularly known as “roundworms”. This is the first record of Ascaridoidea eggs discovered in Crocodyliformes hosts from the Upper Cretaceous of Brazil.

ascaridoidea egg
crocodyliformes host
parasite egg


Abstract: Two new antiarchs are described, from the Late Devonian Hunter Siltstone near Grenfell in south-eastern Australia (Grenfellaspis branagani n.gen., n.sp.), and from the Early Middle Devonian Dayaoshan Group in Guangxi, south-eastern China (Dayaoshania youngi n.gen., n.sp.). New material is described of Xichonolepis qujingensis P'an & Wang, 1978 from the Middle Devonian of Yunnan, and new interpretations are presented for Sinolepis Liu & P'an, 1958 from the Late Devonian of Jiangsu. All four genera are placed in the family Sinolepidae Liu & P' an, of which the most obvious defining character is the much reduced ventral laminae of the anterior and posterior ventrolateral plates of the trunk armour, and the presumed absence of a median ventral plate. Emended diagnoses are presented for the family Sinolepidae and the genera Xichonolepis and Sinolepis. It is suggested that Grenfellaspis and Sinolepis are immediately related, and the biostratigraphic, biogeographic, and palaeogeographic implications of this relationship are discussed. The vertebrate fauna from the Hunter Siltstone is regarded as the youngest nonmarine vertebrate horizon known from the Devonian of south-eastern Australia. A close palaeogeographic connection between south-eastern Australia and South and North China is indicated for the latest Devonian and earliest Carboniferous (late Famennian-early Tournaisian), which contrasts with the distinctive Devonian vertebrate faunas from the two regions in earlier strata. Other Devonian fossil groups showing a similar biogeographic pattern are considered in the context of competing hypotheses concerning the palaeogeographic relationships of Gondwana and Asia during the Middle Palaeozoic. 319 320 Records of the Australian Museum (1992) Vo1.44 RITCHIE, A., S. WANG, G.C. YOUNG & G. ZHANG, 1992. The Sinolepidae, a family of antiarchs (placoderm fishes) from the Devonian of South China and eastern Australia. Records of the Australian Museum 44(3): 319-370.


Callibrachion and Datheosaurus, Two Historical and Previously Mistaken Basal Caseasaurian Synapsids from Europe

Abstract: This study represents a re-investigation of two historical fossil discoveries, Callibrachion gaudryi (Artinskian of France) and Datheosaurus macrourus (Gzhelian of Poland), that were originally classified as haptodontine-grade sphenacodontians and have been lately treated as nomina dubia. Both taxa are here identified as basal caseasaurs based on their overall proportions as well as dental and osteological characteristics that differentiate them from any other major synapsid subclade. As a result of poor preservation, no distinct autapomorphies can be recognized. However, our detailed investigations of the virtually complete skeletons in the light of recent progress in basal synapsid research allow a novel interpretation of their phylogenetic positions. Datheosaurus might represent an eothyridid or basal caseid. Callibrachion shares some similarities with the more derived North American genus Casea. These new observations on Datheosaurus and Callibrachion provide new insights into the early diversification of caseasaurs, reflecting an evolutionary stage that lacks spatulate teeth and broadened phalanges that are typical for other caseid species. Along with Eocasea, the former ghost lineage to the Late Pennsylvanian origin of Caseasauria is further closed. For the first time, the presence of basal caseasaurs in Europe is documented.

datheosaurus
europe
haptodontine-grade sphenacodontian
sphenacodontian
basal caseasaur


Glutamine deamidation: an indicator of antiquity, or preservational quality?

Abstract:
RATIONALE
Much credence has been given in the paleoproteomic community to glutamine deamidation as a proxy for the age of proteins derived from fossil and subfossil material, and this modification has been invoked as a means for determining the endogeneity of molecules recovered from very old fossil specimens.

METHODS
We re-evaluated the relationship between glutamine deamidation and geologic time by examining previously published data from five recent mass spectrometry studies of archeaological fossils. Deamidation values recovered for fossils were graphed against their reported chronologic age using WebPlotDigitizer.

RESULTS
The experimental data that has been produced from fossil material to date show that the extent of glutamine deamidation does not correspond to the absolute age of the specimens being examined, but rather show extreme variation between specimens of similar age and taxonomic affinity.

CONCLUSIONS
Because deamidation rates and levels can be greatly affected by numerous chemical and environmental factors, we propose that glutamine deamidation is better suited as an indicator of preservational quality and/or environmental conditions than a mark of the endogeneity or authenticity of ancient proteins.

indicator
preservational quality
protein
glutamine deamidation