Assessing Raman Spectroscopy as a Prescreening Tool for the Selection of Archaeological Bone for Stable Isotopic Analysis

Abstract: Stable isotope analyses for paleodiet investigations require good preservation of bone protein, the collagen, to obtain reliable stable isotope values. Burial environments cause diagenetic alterations to collagen, especially in the leaching of the organic bone content. The survival of bone protein may be assessed by the weight % collagen, % carbon and % nitrogen yields, but these values are achieved only after destructive chemical processing. A non-destructive method of determining whether bone is suitably preserved would be desirable, as it would be less costly than chemical processing, and would also preserve skeletal collections. Raman analysis is one such potential non-destructive screening method. In previous applications, Raman spectroscopy has been used to test both the alteration of the mineral portion of bone, as well as to indicate the relative amount of organic material within the bone structure. However, there has been no research to test the relationship between the Raman spectroscopic results and the survival of bone protein. We use a set of 41 bone samples from the prehistoric archaeological site of Ban Non Wat, Northeast Thailand, to assess if Raman spectroscopy analysis of the organic-phosphate ratio has a significant correlation with the weight % collagen, and carbon and nitrogen yields obtained by isotopic analysis. The correlation coefficients are highly statistically significant in all cases (r = 0.716 for collagen, r = 0.630 for carbon and r = 0.706 for nitrogen, p≤0.001 for all) with approximately or close to half of the variation in each explained by variation in the organic-phosphate ratio (51.2% for collagen, 39.6% for carbon, and 49.8% for nitrogen). Although the Raman screening method cannot directly quantify the extent of collagen survival, it could be of use in the selection of bone most likely to have viable protein required for reliable results from stable isotope analysis.

raman spectroscopy
selection
isotopic analysis


Evidence for stratigraphy in molluscan death assemblages preserved in seagrass beds: St. Croix, U.S. Virgin Islands

Abstract:
Abstract.
 Death assemblages that occupy the upper tens of centimeters of sediment in shallow-marine settings are often subject to extensive mixing, thereby limiting their usefulness in assessing environmentally mediated compositional changes through time in the local biota. Here, we provide evidence that dense, Thalassia-rich seagrass beds preserve a stratigraphic record of biotic variation because their dense root-rhizome mats inhibit mixing. We sampled benthic mollusk assemblages at seven localities in Thalassia-rich beds around St. Croix, USVI, collecting three separate sediment intervals of ∼13cm each to a total depth of ∼40 cm below the sediment-water interface, and found evidence that sedimentary intervals preserved compositional stratigraphy. Further, some localities displayed systematic, directional changes down-core. An examination of interval-to-interval changes in composition revealed that compositional variation was unique from locality to locality rather than reflecting coordinated, islandwide transitions. In general, however, relative abundances of epifaunal gastropods and small lucinid bivalves tended to decrease with depth below the sediment-water interface. Quantitative comparisons of life-to-death assemblages from each successive sedimentary interval demonstrated that the shallowest death assemblages were typically more similar to the life assemblages than were deeper assemblages, suggesting that deeper intervals provide records of earlier community states.

stratigraphy
death assemblage
seagrass bed


Wind erosion in the Qaidam basin, central Asia: Implications for tectonics, paleoclimate, and the source of the Loess Plateau

Abstract: Liquid water and ice are the dominant agents of erosion and sediment transport in most actively growing mountain belts. An exception is in the western Qaidam basin along the northeastern margin of the Tibetan Plateau, where wind and windblown sand have sculpted enormous yardang fields in actively folding sedimentary strata. Here, we present observations suggesting that since the late Pliocene, wind episodically (during glacial and stadial periods) removed strata from the western Qaidam basin at high rates (>0.12–1.1 mm/yr) and may have accelerated rates of tectonic folding. Severe wind erosion likely occurred during glacial and stadial periods when central Asia was drier and the main axis of the polar jet stream was located ~10° closer to the equator (over the Qaidam basin), as predicted by global climate models. Reconstructed wind patterns, the estimated volume of Qaidam basin material removed by wind, and numerical models of dust transport all support the hypothesis that the Qaidam basin was a major source of dust to the Loess Plateau.


Triassic and Jurassic palaeoclimate development in the Junggar Basin, Xinjiang, Northwest China—a review and additional lithological data

Abstract: The Junggar Basin in the Xinjiang Uygur Autonomous Region (NW China) comprises an almost continuous sequence of continental Mesozoic sediments. The basin was positioned at a latitude of about 45°N from the Permian onwards and existed almost during the entire Mesozoic. As such, it is well suited for studies on palaeoclimatic and palaeoenvironmental changes during this period as tectonic movements of the basin between different climate zones can largely be excluded. Current knowledge about Triassic and Jurassic palaeoclimate development is complemented by new lithological data from the southern part of the basin, ranging from the Late Triassic (Norian) up to the latest Jurassic (Tithonan). Preliminary palynostratigraphical data demonstrate that the base of the Middle Jurassic probably does not coincide with lithostratigraphical formation boundaries (i.e., boundary between Sangonghe and Xishanyiao Formation), but lies within the lower part of the Sangonghe Formation. Humid climates dominated during the Triassic and the Early Jurassic, with only a few drier This article is a contribution to the special issue "Triassic-Jurassic biodiversity, ecosystems, and climate in the Junggar Basin, Xinjiang, Northwest China" Electronic supplementary material The online version of this article

junggar basin
lithological data
triassic


The influence of climate on morphometric traits of fossil populations of
 Microtus arvalis
 and
 M
 .
 agrestis
 from the Carpathian Basin, northern Hungary

Abstract: In this study, we analysed morphometrically fossil populations of Microtus arvalis and M. agrestis from eight late Middle to Late Pleistocene archaeological and palaeontological sites in the Carpathian Basin, northern Hungary. The intra-and interspecific variations in both species can be related to climatic oscillations linked to the onset of the Eemian interglacial and the first phases of Marine Isotope Stage 5. The size of M. agrestis can be correlated with the presence/absence of relatively humid climatic and environmental conditions and of surface water resources (such as marshes and flooded areas). A possible immigration event of M. arvalis populations into the Carpathian Basin, also related to the Eemian interglacial, is also identified. □ common vole, field vole, Hungary, marine Isotope Stage 5, middle-late Pleistocene, morphometrics.

fossil population
carpathian basin
northern hungary


Abstract: Stilwell, J.D., Vitacca, J. & Mays, C., April 2016. South polar greenhouse insects (Arthropoda: Insecta: Coleoptera) from the mid-Cretaceous Tupuangi Formation, Chatham Islands, eastern Zealandia. Alcheringa 40, xxx–xxx. ISSN 0311-5518 Rare insect body fossils have been discovered for the first time after 175 years of research on the Chatham Islands, eastern ‘Zealandia’. The coleopteran (beetle) insects, dated to ca 95 Ma and extracted from fine-grained, upper delta plain facies in the lower Upper Cretaceous (Cenomanian–lowermost Turonian) Tupuangi Formation at Waihere Bay on the remote Pitt Island, represent the most southern, polar-latitude (ca 70–80°S) faunal assemblage from the Cretaceous recorded to date. Three species are represented in the insect fauna: a portion of a segmented abdomen of a probable carabid? ground beetle and two distinct coleopteran elytra, one preserved with a brilliantly iridescent carapace upon discovery, comparable with Cretaceous taxa within the Buprestidae (metallic wood borers), but identification with the Chrysomelidae (leaf beetles) or Tenebrionidae (darkling beetles) can not be discounted entirely. Another specimen has more weakly preserved greenish iridescence and has a morphology consistent with Carabidae; given the preservational deficiencies and rarity of material, the specimens are attributed to Buprestidae? genus et species indeterminate and Carabidae? genus et species indeterminate A and B, respectively. These coleopteran fossils represent the only recorded iridescence in Mesozoic invertebrates from Zealandia. Importantly, these mid-Cretaceous insects existed in South Polar forests near the height of the ‘hothouse’ phase of relatively warm, alternating intervals of full daylight in the summer months and total darkness during the winter, before eastern Zealandia diverged at ca 83 Ma from the Marie Byrd Land region of West Antarctica, as part of the final break-up of Gondwana. Jeffrey D. Stilwell* [jeffrey.stilwell@monash.edu], Jesse V. Vitacca [jesse.vitacca@gmail.com] & Chris Mays [chris.mays@monash.edu], School of Earth, Atmosphere and Environment, Monash University, Clayton VIC 3800, Australia. *Also affiliated with the Australian Museum, 6 College Street, Sydney NSW 2000, Australia.

greenhouse insect
arthropoda
chatham islands


A dicynodont-theropod association in the latest Triassic of Poland

Abstract: It is generally accepted that during the Triassic the composition of tetrapod faunas underwent a series of fundamental transformations, mainly as a result of diversification of archosaurs and decline of therapsids (Benton 1994, 2004, 2006). The last herbivorous basal synapsids, dicynodonts, disappeared from the record in the early Norian of the Americas, about 220 Ma (Langer et al. 2007), being unknown from the Late Triassic of Europe. Here, we report a partially articulated skeleton and isolated bones of a giant rhino-size dicynodont in the Upper Triassic fluvial sediments at Lisowice (Lipie Śląskie clay-pit) in southern Poland. Paleobotanical data indicate an early Rhaetian age for the fauna (Dzik et al. 2008; Niedźwiedzki and Sulej 2008). The dicynodont bones are associated with bones of carnivorous dinosaurs, pterosaurs, as well as capitosaur and plagiosaur amphibians. Dicynodonts were represented in the Germanic Basin throughout the Late Triassic, as proven by findings of smaller dicynodonts in older deposits in the same area, associated there with temnospondyl amphibians. It appears, thus, that the fossil record of tetrapod succession in the Late Triassic was strongly controlled by ecological factors and biased by uneven representation of particular environments. The Lisowice assemblage proves that faunas dominated by dicynodonts did not entirely disappear at least until the end of the Triassic.

tetrapod faunas
dicynodont
late triassic
lipie śląskie clay-pit
germanic basin


Palaeoecology of cave bears as evidenced by dental wear analysis: a review of methods and recent findings

Abstract: Abstract The study of dental wear was first used years ago to infer the palaeoecology of fossil mammals and in particular their diet. Results depend predominantly on the scale of the analysis used. Analyses of dental macrowear, mesowear or microwear do not provide the same type of dietary information, be it about the seasonal, annual or lifetime diet. This contribution focuses on emblematic species, cave bears (Ursidae), in particular Ursus spelaeus spelaeus. Methods used by previous researchers to infer their dietary preferences and thus their palaeoecology are reviewed and compared. This review is complemented by an analysis of several specimens of cave bears from the Goyet cave in Belgium, using dental microwear texture analysis (DMTA), a methodology widely applied for reconstructing palaeodiets. Three main conclusions are drawn here: (1) DMTA is the method that provides the most precise palaeobiological inferences; (2) during the pre-dormancy period, cave bears show dietary flexibility; (3) dental wear alone might be not sufficient to provide a complete reconstruction of the cave bear palaeodiet.

cave bear
belgium
dmta
pre-dormancy period
palaeoecology


An introduction to the palaeoenvironmental reconstruction of the Bathonian (Middle Jurassic) ore-bearing clays at Gnaszyn, Kraków-Silesia Homocline, Poland

Abstract: This paper provides introductory data for multidisciplinary studies on palaeoenvironmental reconstructions of the Bathonian (Middle Jurassic) ore-bearing clays exposed at Gnaszyn, southern Poland. These dark-coloured fine-clastic deposits have been studied for micropalaeontology, sedimentology and geochemistry (published in separate papers within this volume). Brief outlines of the Middle Jurassic palaeogeography of the Polish epicontinental basin and the geology of the Krakow-Silesia Homocline are given. A description of the ore-bearing clays succession exposed in the clay-pit at Gnaszyn is provided, including locations of the sections studied, their ammonite biostratigraphy, brief lithology and macrofossil distribution. The sample positions collected for micropalaeontological and geochemical studies are specified.

palaeoenvironmental reconstruction
bathonian
clay


First remingtonocetid archaeocete (Mammalia, Cetacea) from the middle Eocene of Egypt with implications for biogeography and locomotion in early cetacean evolution

Abstract: Abstract. Remingtonocetidae are Eocene archaeocetes that represent a unique experiment in cetacean evolution. They possess long narrow skulls, long necks, fused sacra, and robust hind limbs. Previously described remingtonocetids are known from middle Eocene Lutetian strata in Pakistan and India. Here we describe a new remingtonocetid, Rayanistes afer, n. gen. n. sp., recovered from a middle to late Lutetian interval of the Midawara Formation in Egypt. The holotype preserves a sacrum with four vertebral centra; several lumbar and caudal vertebrae; an innominate with a complete ilium, ischium, and acetabulum; and a nearly complete femur. The ilium and ischium of Rayanistes are bladelike, rising sharply from the body of the innominate anterior and posterior to the acetabulum, and the acetabular notch is narrow. These features are diagnostic of Remingtonocetidae, but their development also shows that Rayanistes had a specialized mode of locomotion. The expanded ischium is larger than that of any other archaeocete, supporting musculature for powerful retraction of the hind limbs during swimming. Posteriorly angled neural spines on lumbar vertebrae and other features indicate increased passive flexibility of the lumbus. Rayanistes probably used its enhanced lumbar flexibility to increase the length of the power stroke during pelvic paddling. Recovery of a remingtonocetid in Egypt broadens the distribution of Remingtonocetidae and shows that protocetids were not the only semiaquatic archaeocetes capable of dispersal across the southern Tethys Sea.

middle eocene
locomotion
cetacean evolution


An Unusual New Theropod with a Didactyl Manus from the Upper Cretaceous of Patagonia, Argentina

Abstract: Background Late Cretaceous terrestrial strata of the Neuquén Basin, northern Patagonia, Argentina have yielded a rich fauna of dinosaurs and other vertebrates. The diversity of saurischian dinosaurs is particularly high, especially in the late Cenomanian-early Turonian Huincul Formation, which has yielded specimens of rebacchisaurid and titanosaurian sauropods, and abelisaurid and carcharodontosaurid theropods. Continued sampling is adding to the known vertebrate diversity of this unit. Methodology/ Principal Findings A new, partially articulated mid-sized theropod was found in rocks from the Huincul Formation. It exhibits a unique combination of traits that distinguish it from other known theropods justifying erection of a new taxon, Gualicho shinyae gen. et sp. nov. Gualicho possesses a didactyl manus with the third digit reduced to a metacarpal splint reminiscent of tyrannosaurids, but both phylogenetic and multivariate analyses indicate that didactyly is convergent in these groups. Derived characters of the scapula, femur, and fibula supports the new theropod as the sister taxon of the nearly coeval African theropod Deltadromeus and as a neovenatorid carcharodontosaurian. A number of these features are independently present in ceratosaurs, and Gualicho exhibits an unusual mosaic of ceratosaurian and tetanuran synapomorphies distributed throughout the skeleton. Conclusions/ Significance Gualicho shinyae gen. et sp. nov. increases the known theropod diversity of the Huincul Formation and also represents the first likely neovenatorid from this unit. It is the most basal tetatanuran to exhibit common patterns of digit III reduction that evolved independently in a number of other tetanuran lineages. A close relationship with Deltadromaeus from the Kem Kem beds of Niger adds to the already considerable biogeographic similarity between the Huincul Formation and coeval rock units in North Africa.


Silurian bolbozoids and cypridinids (Myodocopa) from Europe: pioneer pelagic ostracods

Abstract: Abstract:  Bolbozoid and cypridinid myodocope ostracods from France, the Czech Republic and Sardinia consist of four genera (one new: Silurocypridina) and at least ten species (eight new: Bolbozoe acuta, B. rugosa, B. parvafraga, Parabolbozoe armoricana, Silurocypridina retroreticulata, S. variostriata, S. calva and Calocaria robusta). They have a functional design, palaeogeographical distribution, depositional setting and faunal associates that suggest that they were swimmers in the water column, living in dim light, relatively deep environments, above near bottom dysoxic/anoxic conditions. These myodocope faunas include some possible pelagic species sensu stricto, with widespread palaeogeographical (transoceanic) distribution, and some species that occupied hyperbenthic niches and were capable of making short incursions to the sediment to scavenge on carrion. These data support the model that Silurian myodocopes were pioneer pelagic ostracods.

bolbozoid
pelagic ostracod
silurian myodocope


Source of Oligocene to Pliocene sedimentary rocks in the Linxia basin in northeastern Tibet from Nd isotopes: Implications for tectonic forcing of climate

Abstract: We used Nd isotopes and trace element data to determine the provenance of sedimentary rocks in the Linxia basin, northeastern Tibet, whose Oligocene through Pliocene sedimentation history has been interpreted to refl ect deposition in a fl exural basin associated with contractional deformation along the northeastern margin of the Tibetan Plateau. Paleozoic‐early Mesozoic metasedimentary source rocks from the KunlunQaidam and Songpan-Ganzi terranes have e Nd values between −11.8 and −16.1, whereas Paleozoic and Mesozoic plutonic source rocks that intrude the metasedimentary rocks have more positive e Nd values between −3.6 and −11.2. Cretaceous sedimentary source rocks display e Nd values of −9.7 and ‐9.9 in the Maxian Shan, north of the Linxia basin, and ‐15.3 in the plateau margin south of the basin. With e Nd values that range between −8.4 and −10.4 before ca. 15 Ma, and −6.2 and −11.8 after ca. 14 Ma, sedimentary rocks of the Linxia basin are less negative than metasedimentary rocks, which are dominant source rocks within the margin of the Tibetan Plateau today. The relatively positive e Nd values of Linxia basin sedimentary rocks could refl ect several possible sources, including (1) a mixture of plutonic and metasedimentary rocks within the northeastern margin of Tibet, (2) Cretaceous sedimentary rocks derived from the north, or (3) loess derived from central Asian deserts. A mass balance calculation indicates that plutonic rocks are not volumetrically signifi cant enough to generate the e Nd values observed in Linxia basin sedimentary rocks through mixing of plutonic and metasedimentary sources. Rare earth element patterns suggest that Cretaceous rocks were not a dominant source of sediment. The Nd isotopic composition and rare earth element pattern of Quaternary loess are similar to older deposits in the Linxia basin and refl ect loess deposited elsewhere in the Loess plateau and the North Pacifi c (e Nd = −8.6 to ‐10.5). In addition, the modern Daxia River, which drains the margin of the plateau today, transports clay and silt with e Nd values of ‐10.5 to ‐10.8 despite the river’s source in more negative metasedimentary rocks of the Kunlun-Qaidam and Songpan-Ganzi terranes, which indicates that the modern fi ne-grained sedimentary budget is dominated by recent loess deposits. Considering the slow sedimentation rates in the Linxia basin, it is likely that loess sources have contributed a signifi cant volume of fi grained sediment to this basin throughout its history. An increase in the range of e Nd values at ca. 14 Ma in the Linxia basin may refl ect increased unroofi ng of the northeastern margin of Tibet, which slightly preceded a change in climate between ca. 13 and 12 Ma in the Linxia basin. A 1.5‰ increase in baseline δ 18 O values of lacustrine carbonates has been interpreted as the result of reorganization of atmospheric circulation and an increase in aridity on the northeastern margin of the Tibetan Plateau, perhaps associated with the plateau having achieved an elevation suffi cient to block moisture from the Indian Ocean and/or Pacifi c Ocean. Similar timing of exhumation and climate change suggests that northeastward and eastward propagation of the plateau margin was responsible for the middle Miocene climate change observed in the Linxia basin.

oligocene
sedimentary rock
northeastern tibet


Geographic Information Systems technology as a morphometric tool for quantifying morphological variation in an ammonoid clade

Abstract: Ammonoids are known for their intraspecific and interspecific morphological variation through ontogeny, particularly in shell shape and ornamentation. Many features covary and individual elements are difficult to homologize, which make qualitative descriptions and widely-used morphometric tools inappropriate for quantifying these complex morphologies. However, spatial analyses conducted in a geographic information systems (GIS) environment allow for quantification and visualization of global shell form. Here, we present a GIS-based methodology in which the variation of shell features is assessed to evaluate evolutionary patterns in an ammonoid clade from the Late Cretaceous Western Interior Seaway of North America. We investigate the ancestral and more variable scaphitid heteromorph ammonoid Hoploscaphites spedeni and its less variable descendant H. nebrascensis. We created three-dimensional (3D) digital models of the fossil shells' lateral surfaces using photogrammetric software and imported the reconstructions into a GIS environment. We used the number of discrete aspect patches and the surface-to-planimetric (3D to 2D) area ratios of the lateral surface as terrain roughness indices. These 3D spatial analyses demonstrate the overlapping morphological ranges of H. spedeni and H. nebrascensis in ornamentation despite differences in shell compression. Additionally, the target for evolutionary change in this clade resides in the macroconch body chamber, which becomes less variable through development from H. spedeni to subsequent H. nebrascensis in macroconchs; however, microconchs retain the ancestral variation through ontogeny. These geospatial analyses not only successfully quantified variation in complex morphologies, but also demonstrated the versatility of this method to address questions related to ontogeny and phylogeny.

tool
morphological variation
ammonoid clade


Active Ooid Growth Driven By Sediment Transport in a High-Energy Shoal, Little Ambergris Cay, Turks and Caicos Islands

Abstract: Ooids are a common component of carbonate successions of all ages and present significant potential as paleoenvironmental proxies, if the mechanisms that control their formation and growth can be understood quantitatively. There are a number of hypotheses about the controls on ooid growth, each offering different ideas on where and how ooids accrete and what role, if any, sediment transport and abrasion might play. These hypotheses have not been well tested in the field, largely due to the inherent challenges of tracking individual grains over long timescales. This study presents a detailed field test of ooid-growth hypotheses on Little Ambergris Cay in the Turks and Caicos Islands, British Overseas Territories. This field site is characterized by westward net sediment transport from waves driven by persistent easterly trade winds. This configuration makes it possible to track changes in ooid properties along their transport path as a proxy for changes in time. Ooid size, shape, and radiocarbon age were compared along this path to determine in which environments ooids are growing or abrading. Ooid surface textures, petrographic fabrics, stable-isotope compositions (δ^(13)C, δ^(18)O, and δ^(34)S), lipid geochemistry, and genetic data were compared to characterize mechanisms of precipitation and degradation and to determine the relative contributions of abiotic (e.g., abiotic precipitation, physical abrasion) and biologically influenced processes (e.g., biologically mediated precipitation, fabric destruction through microbial microboring and micritization) to grain size and character. A convergence of evidence shows that active ooid growth occurs along the transport path in a high-energy shoal environment characterized by frequent suspended-load transport: median ooid size increases by more than 100 μm and bulk radiocarbon ages decrease by 360 yr westward along the ∼ 20 km length of the shoal crest. Lipid and 16S rRNA data highlight a spatial disconnect between the environments with the most extensive biofilm colonization and environments with active ooid growth. Stable-isotope compositions are indistinguishable among samples, and are consistent with abiotic precipitation of aragonite from seawater. Westward increases in ooid sphericity and the abundance of well-polished ooids illustrate that ooids experience subequal amounts of growth and abrasion—in favor of net growth—as they are transported along the shoal crest. Overall, these results demonstrate that, in the Ambergris system, the mechanism of ooid growth is dominantly abiotic and the loci of ooid growth is determined by both carbonate saturation and sediment transport mode. Microbes play a largely destructive, rather than constructive, role in ooid size and fabric.

ooid growth
sediment transport
caicos islands


Integrating Paleobiology, Archeology, and History to Inform Biological Conservation

Abstract: The search for novel approaches to establishing ecological baselines (reference conditions) is constrained by the fact that most ecological studies span the past few decades, at most, and investigate ecosystems that have been substantially altered by human activities for decades, centuries, or more. Paleobiology, archeology, and history provide historical ecological context for biological conservation, remediation, and restoration. We argue that linking historical ecology explicitly with conservation can help unify related disciplines of conservation paleobiology, conservation archeobiology, and environmental history. Differences in the spatial and temporal resolution and extent (scale) of prehistoric, historic, and modern ecological data remain obstacles to integrating historical ecology and conservation biology, but the prolonged temporal extents of historical ecological data can help establish more complete baselines for restoration, document a historical range of ecological variability, and assist in determining desired future conditions. We used the eastern oyster (Crassostrea virginica) fishery of the Chesapeake Bay (U.S.A.) to demonstrate the utility of historical ecological data for elucidating oyster conservation and the need for an approach to conservation that transcends disciplinary boundaries. Historical ecological studies from the Chesapeake have documented dramatic declines (as much as 99%) in oyster abundance since the early to mid‐1800s, changes in oyster size in response to different nutrient levels from the sixteenth to nineteenth centuries, and substantial reductions in oyster accretion rates (from 10 mm/year to effectively 0 mm/year) from the Late Holocene to modern times. Better integration of different historical ecological data sets and increased collaboration between paleobiologists, geologists, archeologists, environmental historians, and ecologists to create standardized research designs and methodologies will help unify prehistoric, historic, and modern time perspectives on biological conservation.

paleobiology
archeology
biological conservation
ecological study
need


A New Fossil Actinistian from the Early Jurassic of Chile and Its Bearing on the Phylogeny of Actinistia

Abstract:
ABSTRACT
 We present the description and taxonomic reassignment of a new genus and species, Atacamaia solitaria, gen. et sp. nov., from Lower Jurassic strata of northern Chile, South America. The fish was previously reported as a new genus of Mawsoniidae, based on one unprepared specimen. The fish is characterized by a combination of numerous intriguing characters, such as the presence of a broad parietal bone partially covered laterally by a series of a few large supraorbital bones, a series of sclerotic bones, a lachrymojugal expanded anteriorly and markedly angled, and a metapterygoid with a well-developed ventral process that is ventral to the dorsal margin of the pterygoid plate. Addition of Atacamaia to previously published matrices produces unexpected collapses of certain nodes in the currently accepted phylogenetic hypothesis of Actinistia, creating many polytomies in the consensus tree. Our cladistic analysis suggests that Atacamaia, gen. et sp. nov., Axelia, and Wimania are closely related and together with Piveteauia, Guizhoucoelacanthus, and Whiteia are members of the order Coelacanthiformes. Based on previous analyses and our results, we recognize this grouping as the family Whiteiidae. Members of Whiteiidae are Triassic forms, except Atacamaia solitaria, gen. et sp. nov., from the Early Jurassic. The new fossil actinistian represents the youngest member of the family and the first discovered on the Paleopacific side of Gondwana; all other members are from China, Madagascar, and Spitsbergen. After comparison of previous hypotheses, we review the higher level taxonomy of Actinistia concerning the monophyly of Coelacanthiformes, Latimeroidei, Mawsoniidae, and Latimeriidae and propose a family diagnosis for Whiteiidae.

new fossil actinistian
early jurassic
actinistia


Spondylolysis, spondylolisthesis, and lumbo-sacral morphology in a medieval English skeletal population.

Abstract: The prevalence of spondylolysis and spondylolisthesis was studied in an adult skeletal series from a rural English medieval archaeological site. Attempts were made to evaluate the association of three aspects of lumbo-sacral skeletal morphology (pelvic incidence (a measure of the anterior inclination of the sacral table), lumbar transverse process width, and the presence of lumbo-sacral spina bifida occulta) with spondylolysis and spondylolisthesis. Results indicated a high prevalence of spondylolysis compared with a modern reference population, but few cases of spondylolisthesis were identified. Analysis of prevalence with respect to age suggests that in the study population, pars interarticularis defects generally formed late in the growth period or early in adult life. The study group showed a high mean pelvic incidence compared with modern Western Europeans, indicating a more steeply inclined sacral table, which may have elevated the risk of developing pars interarticularis defects. However, no statistically valid association could be demonstrated between the presence/absence of spondylolysis and pelvic incidence in the study material. There was no evidence for a link between lumbar transverse process index or lumbo-sacral spina bifida occulta and spondylolysis/spondylolisthesis. It is concluded that the potential role of lumbo-sacral morphology, as well as of activity regimes, should be considered when interpreting spondylolysis in paleopathological studies. If the frequency of spondylolysis is to some extent an indicator of past activity regimes, it may reflect lifestyle in younger individuals rather than in mature adults. Further work investigating the link between spondylolysis and lumbo-sacral morphological variables in premodern populations would be of value.

spondylolisthesis
lumbo-sacral morphology
skeletal series


Palaeoenvironment, palaeoclimate and age of the Brassington Formation (Miocene) of Derbyshire, UK

Abstract: The Brassington Formation is the most extensive Miocene sedimentary succession onshore in the UK. Because of its unique position at the margin of NW Europe, the pollen from this lithostratigraphical unit provides evidence on the development of vegetation affected by North Atlantic currents and hypothesized atmospheric circulation changes during the Middle to Late Miocene climate cooling. Palynostratigraphy suggests that the uppermost Kenslow Member of the Brassington Formation is not coeval. Previously, all occurrences of the Kenslow Member were assumed to be contemporary. The oldest pollen assemblage is from the more southern Bees Nest Pit, which represents a subtropical conifer-dominated forest of late Serravallian age (c. 12 Ma). A younger assemblage was observed from the more northern Kenslow Top Pit; this indicates that a subtropical mixed forest was present during the early Tortonian (11.6–9 Ma). The shift from a conifer-dominated to a mixed forest was related to precipitation. Although the total precipitation did not change between the two assemblages, the younger assemblage had more uniform rainfall throughout the year. The diachronous nature of the Kenslow Member means that the depositional model of the Brassington Formation needs revising, and this will have implications for Neogene to recent uplift of the southern Pennines. Supplementary material: All valid formally defined palynomorph taxa below the generic level that are mentioned in this paper, with full author citations, are available at http://www.geolsoc.org.uk/SUP18889.

brassington formation
miocene
north atlantic current
kenslow top pit


The origin and early evolution of the Osteostraci (Vertebrata): A phylogeny for the Thyestiida

Abstract: Synopsis The Osteostraci are currently regarded as the sister taxon to jawed vertebrates and, as such, osteostracan phylogeny, notably their hypothetical ancestral morphotype, has far reaching ramifications for early vertebrate evolution. The polarity of the group and the monophyly and interrelationships of the proposed constituent clades have not been tested. Here a new phylogeny is proposed for the Thyestiida, the most controversial and informative of the five main orders of Osteostraci. A comprehensive global parsimony approach is applied for the first time. The monophyly of the group, including genera of suspected thyestiid affinities, is firmly demonstrated, as is the monophyly of some constituent groups such as the Siberian Tannuaspidinae. The phylogeny supports the proposals of Janvier (1985a‐c) and is inconsistent with previous ‘Tremataspis‐basal’ models of Osteostracan evolution. Application of the phylogeny to the stratigraphical record demonstrates an early evolution and origin for the Osteostraci and indicates a missing fossil record for the group in the Llandovery, strongly related to facies bias.


1,2,3 = 2,3,4: a solution to the problem of the homology of the digits in the avian hand.

Abstract: Persistent contradictions in well supported empirical findings usually point to important scientific problems and may even lead to exciting new insights. One of the most enduring problems in evolutionary biology is the apparent conflict between paleontological and embryological evidence regarding the homology of the digits in the avian hand (1, 2). We propose that this problem highlights an important feature of morphological change: namely, the possible dissociation between the developmental origin of a particular repeated element and its subsequent individualization into a fully functional character. We argue that, although comparative embryological evidence correctly identifies the homology of the primordial condensations in avians as CII, CIII, and CIV, subsequent anatomical differentiation reflects a frame shift in the developmental identities of the avian digit anlagen in later ontogeny such that CII becomes DI, CIII becomes DII, and CIV becomes DIII.


Gabaleryon, a new genus of widespread early Toarcian polychelidan lobsters

Abstract: Polychelidan lobsters are decapod crustaceans with a unique anatomy: a dorsoventrally flattened carapace, four to five pairs of chelate appendages and a completely reduced rostrum. These crustaceans, like most other malacostracans, are mostly preserved in outcrops in which exceptional preservation occurs, Fossil-Konservat-Lagerstätten. Unfortunately, Lagerstätten are rare, and therefore disjointed both geographically and stratigraphically. This study focuses on a new genus of polychelidan lobster, Gabaleryon gen. nov., with the description of two new Toarcian species, Gabaleryon coquelae sp. nov. from France and G. garassinoi sp. nov. from Italy. The long-standing question of the generic assignment of Eryon moorei (Toarcian, UK) is resolved and the species is ascribed to Gabaleryon. The occurrences of these three species and a fourth, Gabaleryon sp. 1 (Toarcian, Germany), provide a first palaeobiogeographical indication that the Fossil-Lagerstätten in which they occur were linked during Toarcian times. The occurrence of a possible fifth species of Gabaleryon in the late Bajocian–early Bathonian of France may extend the stratigraphical distribution of the new genus. Finally, these new species increase our knowledge of fossil polychelidans and place the Toarcian as their second peak of palaeobiodiversity, after that at the Kimmeridgian–Tithonian boundary. http://zoobank.org/urn:lsid:zoobank.org:pub:073513BD-A0D8-4A5B-B9DE-1C61781077DC

new genus
polychelidan lobster
gabaleryon


Morphological disparity and developmental patterning: contribution of phacopid trilobites

Abstract: In trilobites as in many others extinct organisms, our understanding of the mechanisms of evolution is based on morphological and ontogenetic features. Data from ontogenetic development are essential to provide an insight into the origins of evolutionary changes. In phacopid trilobites, detailed studies of ontogenetic series have been achieved using quantitative methods. A comparison of ontogenetic trajectories of closely related species has been conducted to understand how the both morphological disparity and developmental patterning of different ontogenetic stages were structured and to determine how the environmental or developmental constraints influenced morphological changes in trilobites. Study of such morphological disparity in developmental evolution requires knowledge of morphological features and timing and rate of development among closely related species. At a macroevolutionary scale, such quantitative studies should allow us (1) to determine the impact of individual ontogenies on morphological diversification and (2) to identify the evolutionary patterns in Phacopidae during 100 Ma of existence.

developmental patterning
phacopid trilobite
trilobite


Abstract: Corresponding autor’s contact: marco.viaretti@studenti.unimi.it How to cite: Viaretti et al. (2020). An exceptionally well-preserved scorpion from the Besano Formation (Monte San Giorgio, Middle Triassic, Southern Alps): preliminary study. Fossilia, Volume 2020: 53-55. https://doi.org/10.32774/ FosRepPal.2020.0614 Fossilia Reports in Palaeontology An exceptionally well-preserved scorpion from the Besano Formation (Monte San Giorgio, Middle Triassic, Southern Alps): preliminary study

well-preserved scorpion
middle triassic
southern alps


Competition, clade replacement, and a history of cyclostome and cheilostome bryozoan diversity

Abstract: One of the striking yet scarcely documented episodes of clade replacement in the post-Paleozoic fossil record is the decline of cyclostome Bryozoa and the corresponding, rapid diversification of cheilostome Bryozoa. These clades are closely associated morphologically and phylogenetically, and their ecological similarities have previously led to the inference that competition was a primary cause of the overt pattern of replacement. Alternatively, previous compilations of bryozoan families and genera have implied that extinctions at the Cretaceous/Tertiary boundary differentially affected cyclostomes, and thus were also an important factor in the transition. We first evaluated the ecological context for competition between the two clades, then updated and reexamined the history of absolute family diversity for bryozoans in consecutive geologic stages from Jurassic to Recent. The resulting trends echo the patterns shown in earlier family level compilations, but indicate a slight shift in the frequency of cheilostome family originations from Late Cretaceous to early Paleogene. The relative fall in cyclostome family diversity at the Cretaceous/Tertiary boundary is significantly less than shown in earlier genus level compilations. We then assessed these various compilations of absolute diversity by analyzing species counts and percentages in 728 fossil assemblages, primarily from North America and Europe, over the same time interval. Cyclostome species overwhelmingly dominate assemblages from Jurassic through Cenomanian, then decline significantly in average percentage dominance through the Campanian. Cheilostomes are predominant in Campanian and later assemblages. Cyclostome species percentages do decrease overall through the Tertiary, but this decrease is small and non-uniform, varying around 30%, with a sharp drop in the Late Neogene. Our within-assemblage results indicate that as cheilostomes radiate, their mean species diversity, maximum diversity, and variance all increase, thereby accounting for much of the decline in average percentage of cyclostomes within assemblages. While this result does not exclude a role for competition, an hypothesis of relative decline in cyclostome species richness based on competitive extinction alone seems unlikely. Further, despite decreases in absolute species counts following end-Cretaceous extinctions, within-assemblage percentages of cheilostome or cyclostome species show only slight change relative to one another. Comparison of these and earlier diversity compilations indicates that the dynamics of bryozoan clade replacement may be perceived differently at different ecologic scales or taxonomic ranks.

clade replacement
cyclostome
cheilostome
bryozoan
competition


Global carbon cycle perturbation across the Eocene-Oligocene climate transition

Abstract: The Eocene-Oligocene transition (EOT), ~34?Ma, marks a tipping point in the long-term Cenozoic greenhouse to icehouse climate transition. Paleorecords reveal stepwise rapid cooling and ice growth across the EOT tightly coupled to a transient benthic ?13C excursion and a major and permanent deepening of the carbonate compensation depth (CCD). Based on biogeochemical box modeling, Merico et al. (2008) suggested that a combination of (1) glacioeustatic sea level fall-induced shelf-basin carbonate burial fractionation and (2) shelf carbonate weathering can account for the carbon cycle perturbation, but this finding has been questioned. Alternative proposed mechanisms include increased ocean ventilation, decreased carbonate burial, increased organic carbon burial, increased silicate weathering, and increased ocean calcium concentration. Here we use an improved version of the biogeochemical box model of Merico et al. (2008) to reevaluate these competing hypotheses and an additional mechanism, the expansion of “carbon capacitors” such as permafrost and peatlands. We find that changes in calcium concentration, silicate weathering, and carbonate or organic carbon burial each yield a response that is fundamentally at odds with the form and/or sign of the paleorecords. Shelf-basin carbonate burial fractionation (CCD change), plus shelf carbonate weathering, sequestration of 12C-enriched carbon into carbon capacitors, and possibly increased ocean ventilation (?13C excursion), offers the best fit to the paleorecords. Further work is needed to understand why the EOT carbon cycle perturbation is so unique when the forcing mechanisms hypothesized to be responsible (cooling and ice growth) are not peculiar to this event.

carbon cycle perturbation
climate transition
biogeochemical box model


A new proposal concerning the botanical origin of Baltic amber

Abstract: Baltic amber constitutes the largest known deposit of fossil plant resin and the richest repository of fossil insects of any age. Despite a remarkable legacy of archaeological, geochemical and palaeobiological investigation, the botanical origin of this exceptional resource remains controversial. Here, we use taxonomically explicit applications of solid-state Fourier-transform infrared (FTIR) microspectroscopy, coupled with multivariate clustering and palaeobotanical observations, to propose that conifers of the family Sciadopityaceae, closely allied to the sole extant representative, Sciadopitys verticillata, were involved in the genesis of Baltic amber. The fidelity of FTIR-based chemotaxonomic inferences is upheld by modern–fossil comparisons of resins from additional conifer families and genera (Cupressaceae: Metasequoia; Pinaceae: Pinus and Pseudolarix). Our conclusions challenge hypotheses advocating members of either of the families Araucariaceae or Pinaceae as the primary amber-producing trees and correlate favourably with the progressive demise of subtropical forest biomes from northern Europe as palaeotemperatures cooled following the Eocene climate optimum.

botanical origin
baltic amber
family araucariaceae
tree
amber deposit


Supplementary cranial description of the types of Edmontosaurus regalis (Ornithischia: Hadrosauridae), with comments on the phylogenetics and biogeography of Hadrosaurinae

Abstract: The cranial anatomy of the flat-skulled hadrosaurine Edmontosaurus regalis (Ornithischia: Hadrosauridae) is extensively described here, based on the holotype and paratype collected from the middle part of the Horseshoe Canyon Formation in southern Alberta. Focus is given to previously undocumented features of ontogenetic and phylogenetic importance. This description facilitates overall osteological comparisons between E. regalis and other hadrosaurids (especially E. annectens), and revises the diagnosis of E. regalis, to which a new autapomorphy (the dorsal half of the jugal anterior process bearing a sharp posterolateral projection into the orbit) is added. We consider the recently named Ugrunaaluk kuukpikensis from the upper Campanian/lower Maastrichtian of Alaska a nomen dubium, and conservatively regard the Alaskan material as belonging to Edmontosaurus sp.. A phylogenetic analysis of Hadrosauroidea using maximum parsimony further corroborates the sister-taxon relationship between E. regalis and E. annectens. In the strict consensus tree, Hadrosaurus foulkii occurs firmly within the clade comprising all non-lambeosaurine hadrosaurids, supporting the taxonomic scheme that divides Hadrosauridae into Hadrosaurinae and Lambeosaurinae. Within Edmontosaurini, Kerberosaurus is posited as the sister taxon to the clade of Shantungosaurus + Edmontosaurus. The biogeographic reconstruction of Hadrosaurinae in light of the time-calibrated cladogram and probability calculation of ancestral areas for all internal nodes reveals a significantly high probability for the North American origin of the clade. However, the Laramidia–Appalachia dispersals around the Santonian–Campanian boundary, inferred from the biogeographic scenario for the North American origin of Hadrosaurinae, are in conflict with currently accepted paleogeographic models. By contrast, the Asian origin of Hadrosaurinae with its relatively low probability resulting from the biogeographic analysis is worth seriously considering, despite the lack of fossil material from the Santonian and lower Campanian of Asia. Extra fossil collecting in appropriate geographic locations and stratigraphic intervals of Asia and Europe will help to clarify the biogeographic dynamics of hadrosaurine dinosaurs in the near future.

edmontosaurus regalis
ornithischia
hadrosauridae


Ontogeny in the fossil record: diversification of body plans and the evolution of “aberrant” symmetry in Paleozoic echinoderms

Abstract: Abstract Echinoderms have long been characterized by the presence of ambulacra that exhibit pentaradiate symmetry and define five primary body axes. In reality, truly pentaradial ambulacral symmetry is a condition derived only once in the evolutionary history of echinoderms and is restricted to eleutherozoans, the clade that contains most living echinoderm species. In contrast, early echinoderms have a bilaterally symmetrical 2–1–2 arrangement, with three ambulacra radiating from the mouth. Branching of the two side ambulacra during ontogeny produces the five adult rays. During the Cambrian Explosion and Ordovician Radiation, some 30 clades of echinoderms evolved, many of which have aberrant ambulacral systems with one to four rays. Unfortunately, no underlying model has emerged that explains ambulacral homologies among disparate forms. Here we show that most Paleozoic echinoderms are characterized by uniquely identifiable ambulacra that develop in three distinct postlarval stages. Nearly all “aberrant” echinoderm morphologies can be explained by the paedomorphic ambulacra reduction (PAR) model through the loss of some combination of these growth stages during ontogeny. Superficially similar patterns of ambulacral reduction in distantly related clades have resulted from the parallel loss of homologous ambulacra during ontogeny. Pseudo-fivefold symmetry seen in Blastoidea and the true fivefold symmetry seen in Eleutherozoa result from great reduction and total loss, respectively, of the 2– 1–2 symmetry early in ontogeny. These ambulacral variations suggest that both developmental and ecological constraints affect the evolution of novel echinoderm body plans.


Late Pleistocene Carbon Cycle Revisited by Considering Solid Earth Processes

Abstract: The importance of volcanic CO2 release, continental weathering, and coral reef growth on the global carbon cycle has been highlighted by several different studies. Based on these independent approaches, we here revisit the last 800 kyr with the box model BICYCLE, which has been extended to be able to address these solid Earth contributions to the carbon cycle. We show that the volcanic outgassing of CO2 as a function of sea level change from mid‐ocean ridges and hot spot island volcanoes cannot be the generic process that leads during phases of falling obliquity to a sea level‐CO2 decoupling as has been suggested before. The combined contribution from continental and marine volcanism, if both lagging sea level change by 4 kyr, might have added up to 13 ppm to the glacial/interglacial CO2 rise. Coral reef growth as suggested by an independent model is during glacial terminations about an order of magnitude too high to be reconciled with meaningful carbon cycle dynamics. Global riverine input of bicarbonate caused by silicate and carbonate weathering is suggested to have been stable over Termination I. However, if weathering fluxes are changed by up to 50% in sensitivity experiments, the corresponding bicarbonate input might contribute less than 20 ppm to the deglacial atmospheric CO2 rise. The overall agreement of results with the new process‐based sediment module and the previously applied time‐delayed response function to mimic carbonate compensation gives confidence in the results obtained in previous applications of the BICYCLE model without solid Earth processes.

solid earth process
weathering
global carbon cycle
riverine input
bicarbonate


The Vicissicaudata revisited – insights from a new aglaspidid arthropod with caudal appendages from the Furongian of China

Abstract: Cambrian marine ecosystems were dominated by arthropods, and more specifically artiopods. Aglaspidids represent an atypical group amongst them, not the least because they evolved and rapidly diversified during the late Cambrian, a time interval between the two diversification events of the Early Palaeozoic. Recent phylogenetic analyses have retrieved aglaspidids within the Vicissicaudata, a potentially important, but difficult to define clade of artiopods. Here we describe a new aglaspidid from the Furongian Guole Konservat-Lagerstätte of South China. This taxon displays a pretelsonic segment bearing non-walking appendages, features as-yet known in all vicissicaudatans, but aglaspidids. A new comprehensive phylogenetic analysis provides strong support for the legitimacy of a monophyletic clade Vicissicaudata, and demonstrates the pertinence of new characters to define Aglaspidida. It also motivates important changes to the systematics of the phylum, including the elevation of Artiopoda to the rank of subphylum, and the establishment of a new superclass Vicissicaudata and a new aglaspidid family Tremaglaspididae. Two diversification pulses can be recognized in the early history of artiopods – one in the early Cambrian (trilobitomorphs) and the other in the late Cambrian (vicissicaudatans). The discrepancy between this pattern and that traditionally depicted for marine invertebrates in the Early Palaeozoic is discussed.

appendage
phylogenetic analysis
aglaspidida


Abstract: The Huehuetla quarry is a new fossiliferous site located near the town of the same name, into the region of Sierra Norte, northern Puebla, Mexico. This work represents the formal beginning of paleontological research on this site. This quarry occupies an area of about one hectare that is scarcely exploited with commercial purposes. The rocks rarely extracted in this site are slabs of nice jet-black carbonated shales with microscopic crystals of pyrite; which also are resistant, oily and stinky. The fossils recovered in these slabs belong to different marine vertebrate taxa, which include complete and articulated specimens as well as isolated bones. When it is preserved, the calcium phosphate of these bones is softened and filled with large calcite and pyrite crystals. Taxa represented in Huehuetla quarry constitute a peculiar assemblage that includes Nursallia aff. tethysensis, Tselfatia formosa, Goulmimichthys roberti, Hastichthys, indeterminate species of Enchodus and Clupeidae, as well as an indeterminate mosasaur. This is the first report of the pycnodontid N. tethysensis and of the dercetid Hastichthys fish all over America. This work provides evidence supporting the taxonomical validity of the species G. roberti. Based on its fossil content and lithology, it is determined that the fossil bearing strata of the Huehuetla quarry are part of the Turonian marine deposits of the Agua Nueva Formation. Jesús Alvarado-Ortega. Instituto de Geología, Universidad Nacional Autónoma de México, Circuito de la Investigación S/N, Ciudad Universitaria, Delegación Coyoacán, Ciudad de México 04510, México. alvarado@geologia.unam.mx Kleyton Magno Cantalice Severiano. Instituto de Geología, Universidad Nacional Autónoma de México, Circuito de la Investigación S/N, Ciudad Universitaria, Delegación Coyoacán, Ciudad de México 04510, México. kleytonbio@yahoo.com.br Jair Israel Barrientos-Lara. Posgrado en Ciencias Biológicas, Universidad Nacional Autónoma de México, Circuito de la Investigación S/N, Ciudad Universitaria, Delegación Coyoacán, Ciudad de México 04510, México. j4ir@me.com Alvarado-Ortega, Jesús, Cantalice Severiano, Kleyton Magno, Barrientos-Lara, Jair Israel, Díaz-Cruz, Jesús Alberto, and ThanMarchese, Bruno Andrés. 2019. The Huehuetla quarry, a Turonian deposit of marine vertebrates in the Sierra Norte of Puebla, central Mexico. Palaeontologia Electronica 22.1.13A 1-20. https://doi.org/10.26879/921 palaeo-electronica.org/content/2019/2450-huehuetla-turonian-vertebrates Copyright: March 2019 Paleontological Society. This is an open access article distributed under the terms of Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0), which permits users to copy and redistribute the material in any medium or format, provided it is not used for commercial purposes and the original author and source are credited, with indications if any changes are made. creativecommons.org/licenses/by-nc-sa/4.0/ ALVARADO-ORTEGA ET AL.: HUEHUETLA TURONIAN VERTEBRATES Jesús Alberto Díaz-Cruz. Posgrado en Ciencias Biológicas, Universidad Nacional Autónoma de México, Circuito de la Investigación S/N, Ciudad Universitaria, Delegación Coyoacán, Ciudad de México 04510, México. vertebrata.j@gmail.com Bruno Andrés Than-Marchese. Museo de Paleontología “Eliseo Palacios Aguilera”, Secretaría de Medio Ambiente e Historia Natural, Calzada de Los Hombres Ilustres s/n., Tuxtla Gutiérrez, Chiapas, México. bruthmar@gmail.com

huehuetla quarry
turonian deposit
marine vertebrate


The functional morphology of the manus in the tridactyl equids Merychippus and Mesohippus: paleontological inferences from neontological models

Abstract: ABSTRACT An investigation of the kinematics and mechanics of the manus of extant Equus and Tapirus is used as the basis for interpreting the functional morphology of the manus in the extinct tridactyl equids Mesohippus and Merychippus. The shape of the articular surfaces of each joint in the manus of the extant forms is related to the kinematics of the limb, and the probable soft-tissue anatomy and locomotory kinematics of the two fossils are reconstructed by comparing joint shapes among the four genera. The results support the conclusion of Camp and Smith (1942) that Mesohippus had a padded subunguligrade manus, similar to that of Tapirus, while Merychippus was fully unguligrade like Equus. However, all three equids have similar cursorial adaptations, not shared with Tapirus, which include the structure of the carpus and elongation of the distal segments of the limb. The differences in foot structure between Mesohippus and the unguligrade equids may be related to size. Only two, relatively minor, anatomi...

functional morphology
manus
merychippus
mesohippus
equus


The giant pliosaurid that wasn’t: revising the marine reptiles from the Kimmeridgian (Upper Jurassic) of Krzyżanowice, Poland

Abstract: Marine reptiles from the Upper Jurassic of Central Europe are rare and often fragmentary, which hinders their precise taxonomic identification and their placement in a palaeobiogeographic context. Recent fieldwork in the Kimmeridgian of Krzyżanowice, Poland, a locality known from turtle remains originally discovered in the 1960s, has reportedly provided additional fossils thought to indicate the presence of a more diverse marine reptile assemblage, including giant pliosaurids, plesiosauroids, and thalattosuchians. Based on its taxonomic composition, the marine tetrapod fauna from Krzyżanowice was argued to represent part of the “Matyja-Wierzbowski Line”—a newly proposed palaeobiogeographic belt comprising faunal components transitional between those of the Boreal and Mediterranean marine provinces. Here, we provide a detailed re-description of the marine reptile material from Krzyżanowice and reassess its taxonomy. The turtle remains are proposed to represent a “plesiochelyid” thalassochelydian ( Craspedochelys ? sp.) and the plesiosauroid vertebral centrum likely belongs to a cryptoclidid. However, qualitative assessment and quantitative analysis of the jaws originally referred to the colossal pliosaurid Pliosaurus clearly demonstrate a metriorhynchid thalattosuchian affinity. Furthermore, these metriorhynchid jaws were likely found at a different, currently indeterminate, locality. A tooth crown previously identified as belonging to the thalattosuchian Machimosaurus is here considered to represent an indeterminate vertebrate. The revised taxonomy of the marine reptiles from Krzyżanowice, as well as the uncertain provenance of the metriorhynchid specimen reported from the locality, cast doubt on the palaeobiogeographic significance of the assemblage.

giant pliosaurid
marine reptile
kimmeridgian


Global Diversity of Brittle Stars (Echinodermata: Ophiuroidea)

Abstract: This review presents a comprehensive overview of the current status regarding the global diversity of the echinoderm class Ophiuroidea, focussing on taxonomy and distribution patterns, with brief introduction to their anatomy, biology, phylogeny, and palaeontological history. A glossary of terms is provided. Species names and taxonomic decisions have been extracted from the literature and compiled in The World Ophiuroidea Database, part of the World Register of Marine Species (WoRMS). Ophiuroidea, with 2064 known species, are the largest class of Echinodermata. A table presents 16 families with numbers of genera and species. The largest are Amphiuridae (467), Ophiuridae (344 species) and Ophiacanthidae (319 species). A biogeographic analysis for all world oceans and all accepted species was performed, based on published distribution records. Approximately similar numbers of species were recorded from the shelf (n = 1313) and bathyal depth strata (1297). The Indo-Pacific region had the highest species richness overall (825 species) and at all depths. Adjacent regions were also relatively species rich, including the North Pacific (398), South Pacific (355) and Indian (316) due to the presence of many Indo-Pacific species that partially extended into these regions. A secondary region of enhanced species richness was found in the West Atlantic (335). Regions of relatively low species richness include the Arctic (73 species), East Atlantic (118), South America (124) and Antarctic (126).

echinodermata
ophiuroidea
global diversity


Evolutionary pathways toward gigantism in sharks and rays

Abstract: Through elasmobranch (sharks and rays) evolutionary history, gigantism evolved multiple times in phylogenetically distant species, some of which are now extinct. Interestingly, the world's largest elasmobranchs display two specializations found never to overlap: filter feeding and mesothermy. The contrasting lifestyles of elasmobranch giants provide an ideal case study to elucidate the evolutionary pathways leading to gigantism in the oceans. Here, we applied a phylogenetic approach to a global dataset of 459 taxa to study the evolution of elasmobranch gigantism. We found that filter feeders and mesotherms deviate from general relationships between trophic level and body size, and exhibit significantly larger sizes than ectothermic‐macropredators. We confirm that filter feeding arose multiple times during the Paleogene, and suggest the possibility of a single origin of mesothermy in the Cretaceous. Together, our results elucidate two main evolutionary pathways that enable gigantism: mesothermic and filter feeding. These pathways were followed by ancestrally large clades and facilitated extreme sizes through specializations for enhancing prey intake. Although a negligible percentage of ectothermic‐macropredators reach gigantic sizes, these species lack such specializations and are correspondingly constrained to the lower limits of gigantism. Importantly, the very adaptive strategies that enabled the evolution of the largest sharks can also confer high extinction susceptibility.


Establishing a time-scale for plant evolution.

Abstract: • Plants have utterly transformed the planet, but testing hypotheses of causality requires a reliable time-scale for plant evolution. While clock methods have been extensively developed, less attention has been paid to the correct interpretation and appropriate implementation of fossil data. • We constructed 17 calibrations, consisting of minimum constraints and soft maximum constraints, for divergences between model representatives of the major land plant lineages. Using a data set of seven plastid genes, we performed a cross-validation analysis to determine the consistency of the calibrations. Six molecular clock analyses were then conducted, one with the original calibrations, and others exploring the impact on divergence estimates of changing maxima at basal nodes, and prior probability densities within calibrations. • Cross-validation highlighted Tracheophyta and Euphyllophyta calibrations as inconsistent, either because their soft maxima were overly conservative or because of undetected rate variation. Molecular clock analyses yielded estimates ranging from 568-815 million yr before present (Ma) for crown embryophytes and from 175-240 Ma for crown angiosperms. • We reject both a post-Jurassic origin of angiosperms and a post-Cambrian origin of land plants. Our analyses also suggest that the establishment of the major embryophyte lineages occurred at a much slower tempo than suggested in most previous studies. These conclusions are entirely compatible with current palaeobotanical data, although not necessarily with their interpretation by palaeobotanists.


Ancestor–descendant relationships in evolution: origin of the extant pygmy right whale, Caperea marginata

Abstract: Ancestor–descendant relationships (ADRs), involving descent with modification, are the fundamental concept in evolution, but are usually difficult to recognize. We examined the cladistic relationship between the only reported fossil pygmy right whale, †Miocaperea pulchra, and its sole living relative, the enigmatic pygmy right whale Caperea marginata, the latter represented by both adult and juvenile specimens. †Miocaperea is phylogenetically bracketed between juvenile and adult Caperea marginata in morphologically based analyses, thus suggesting a possible ADR—the first so far identified within baleen whales (Cetacea: Mysticeti). The †Miocaperea–Caperea lineage may show long-term morphological stasis and, in turn, punctuated equilibrium.

pygmy
whale
ancestor–descendant relationship


Global microbial carbonate proliferation after the end-Devonian mass extinction: Mainly controlled by demise of skeletal bioconstructors

Abstract: Microbial carbonates commonly flourished following mass extinction events. The end-Devonian (Hangenberg) mass extinction event is a first-order mass extinction on the scale of the ‘Big Five’ extinctions. However, to date, it is still unclear whether global microbial carbonate proliferation occurred after the Hangenberg event. The earliest known Carboniferous stromatolites on tidal flats are described from intertidal environments of the lowermost Tournaisian (Qianheishan Formation) in northwestern China. With other early Tournaisian microbe-dominated bioconstructions extensively distributed on shelves, the Qianheishan stromatolites support microbial carbonate proliferation after the Hangenberg extinction. Additional support comes from quantitative analysis of the abundance of microbe-dominated bioconstructions through the Famennian and early Tournaisian, which shows that they were globally distributed (between 40° latitude on both sides of the palaeoequator) and that their abundance increased distinctly in the early Tournaisian compared to the latest Devonian (Strunian). Comparison of variations in the relative abundance of skeleton- versus microbe-dominated bioconstructions across the Hangenberg and ‘Big Five’ extinctions suggests that changes in abundance of skeletal bioconstructors may play a first-order control on microbial carbonate proliferation during extinction transitions but that microbial proliferation is not a general necessary feature after mass extinctions.

microbial carbonate proliferation
mass extinction
skeletal bioconstructor


First glimpse into Lower Jurassic deep-sea biodiversity: in situ diversification and resilience against extinction

Abstract: Owing to the assumed lack of deep-sea macrofossils older than the Late Cretaceous, very little is known about the geological history of deep-sea communities, and most inference-based hypotheses argue for repeated recolonizations of the deep sea from shelf habitats following major palaeoceanographic perturbations. We present a fossil deep-sea assemblage of echinoderms, gastropods, brachiopods and ostracods, from the Early Jurassic of the Glasenbach Gorge, Austria, which includes the oldest known representatives of a number of extant deep-sea groups, and thus implies that in situ diversification, in contrast to immigration from shelf habitats, played a much greater role in shaping modern deep-sea biodiversity than previously thought. A comparison with coeval shelf assemblages reveals that, at least in some of the analysed groups, significantly more extant families/superfamilies have endured in the deep sea since the Early Jurassic than in the shelf seas, which suggests that deep-sea biota are more resilient against extinction than shallow-water ones. In addition, a number of extant deep-sea families/superfamilies found in the Glasenbach assemblage lack post-Jurassic shelf occurrences, implying that if there was a complete extinction of the deep-sea fauna followed by replacement from the shelf, it must have happened before the Late Jurassic.

deep-sea biodiversity
situ diversification
biota


Abstract: Agnolin, F.L., July 2016. Unexpected diversity of ratites (Aves, Palaeognathae) in the early Cenozoic of South America: palaeobiogeographical implications. Alcheringa 41, xxx–xxx. ISSN 0311-5518. Ratitae is represented in South America exclusively by Rheidae. Recently, the oldest purported fossil rheid, Diogenornis fragilis, was attributed by several authors to various other ratite clades. A new revision of museum fossil specimens from Argentina has resulted in the discovery of several ratite specimens that clearly do not belong to Rheidae, but resemble other clades. The newly identified specimens derive from Paleogene and Miocene strata. The great diversity of non-rheid Patagonian ratites ended via extinction of several groups by the late Miocene, probably owing to enhanced aridity that also favoured the dispersal of arid-adapted rheids. The new specimens described here reinforce the hypothesis that the traditional vicariant biogeographical model, which proposes ratite clades originated exclusively before the breakup of the Gondwana supercontinent, is questionable owing to the unexpected diversity of various ratite clades in South America, and also in Europe and Africa. This might indicate that the history of Ratitae was more complex than previously envisioned. Federico L. Agnolin* [fedeagnolin@yahoo.com.ar], Laboratorio de Anatomía Comparada y Evolución de los Vertebrados, Museo Argentino de Ciencias Naturales ‘Bernardino Rivadavia’, Av. Ángel Gallardo, 470 (1405), Buenos Aires, Argentina. *Also affiliated with: Fundación de Historia Natural ‘Félix de Azara’, Departamento de Ciencias Naturales y Antropología, Universidad Maimónides, Hidalgo 775 (C1405BDB) Ciudad Autónoma de Buenos Aires, República Argentina.

palaeognathae
early cenozoic
palaeobiogeographical implication


New evidence of broader diets for archaic Homo populations in the northwestern Mediterranean

Abstract: Taphonomic data suggest that early humans in Europe had more variable diet breadths than assumed by current evolutionary models. Investigating diet breadth is critical for understanding how archaic Homo populations, including Neanderthals, competed for seasonally scarce resources. The current consensus in Western Europe is that ungulates formed the bulk of the human diet during the Lower and Middle Paleolithic, while small fast prey taxa were virtually ignored. Here, we present a multisite taphonomic study of leporid assemblages from Southern France that supports frequent exploitation of small fast game during marine isotope stages 11 to 3. Along with recent evidence from Iberia, our results indicate that the consumption of small fast game was more common prior to the Upper Paleolithic than previously thought and that archaic hominins from the northwestern Mediterranean had broader diets than those from adjacent regions. Although likely of secondary importance relative to ungulates, the frequent exploitation of leporids documented here implies that human diet breadths were substantially more variable within Europe than assumed by current evolutionary models.

archaic homo population
northwestern mediterranean
broad diet


Early Levallois technology and the Lower to Middle Paleolithic transition in the Southern Caucasus

Abstract: An early assemblage of obsidian artifacts Levallois technology is the name for the stone knapping technique used to create tools thousands of years ago. The technique appeared in the archeological record across Eurasia 200 to 300 thousand years ago (ka) and appeared earlier in Africa. Adler et al. challenge the hypothesis that the technique's appearance in Eurasia was the result of the expansion of hominins from Africa. Levallois obsidian artifacts in the southern Caucasus, dated at 335 to 325 ka, are the oldest in Eurasia. This suggests that Levallois technology may have evolved independently in different hominin populations. Stone technology cannot thus be used as a reliable indicator of Paleolithic human population change and expansion. Science, this issue p. 1609 An assemblage of obsidian artifacts suggests independent origins of stone knapping in different hominin populations. The Lower to Middle Paleolithic transition (~400,000 to 200,000 years ago) is marked by technical, behavioral, and anatomical changes among hominin populations throughout Africa and Eurasia. The replacement of bifacial stone tools, such as handaxes, by tools made on flakes detached from Levallois cores documents the most important conceptual shift in stone tool production strategies since the advent of bifacial technology more than one million years earlier and has been argued to result from the expansion of archaic Homo sapiens out of Africa. Our data from Nor Geghi 1, Armenia, record the earliest synchronic use of bifacial and Levallois technology outside Africa and are consistent with the hypothesis that this transition occurred independently within geographically dispersed, technologically precocious hominin populations with a shared technological ancestry.

levallois technology
middle paleolithic transition
southern caucasus


Paleotemperatures and ice volume of the past 27 Myr revisited with paired Mg/Ca and 18O/16O measurements on benthic foraminifera

Abstract: [1] We explore the applicability of paired Mg/Ca and 18O/16O measurements on benthic foraminifera from Southern Ocean site 747 to paleoceanographic reconstructions on pre-Pleistocene timescales. We focus on the late Oligocene through Pleistocene (27–0 Ma) history of paleotemperatures and the evolution of the δ18O values of seawater (δ18Osw) at a temporal resolution of ∼100–200 kyr. Absolute paleotemperature estimates depend on assumptions of how Mg/Ca ratios of seawater have changed over the past 27 Myr, but relative changes that occur on geologically brief timescales are robust. Results indicate that at the Oligocene to Miocene boundary (23.8 Ma), temperatures lag the increase in global ice-volume deduced from benthic foraminiferal δ18O values, but the smaller-scale Miocene glaciations are accompanied by ocean cooling of ∼1°C. During the mid-Miocene phase of Antarctic ice sheet growth (∼15–13 Ma), water temperatures cool by ∼3°C. Unlike the benthic foraminiferal δ18O values, which remain relatively constant thereafter, temperatures vary (by 3°C) and reach maxima at ∼12 and ∼8.5 Ma. The onset of significant Northern Hemisphere glaciation during the late Pliocene is synchronous with an ∼4°C cooling at site 747. A comparison of our δ18Osw curve to the Haq et al. [1987] sea level curve yields excellent agreement between sequence boundaries and times of increasing seawater 18O/16O ratios. At ∼12–11 Ma in particular, when benthic foraminiferal δ18O values do not support a further increase in ice volume, the δ18Osw curve comes to a maximum that corresponds to a major mid-Miocene sea level regression. The agreement between the character of our Mg/Ca-based δ18Osw curve and sequence stratigraphy demonstrates that benthic foramaniferal Mg/Ca ratios can be used to trace the δ18Osw on pre-Pleistocene timescales despite a number of uncertainties related to poorly constrained temperature calibrations and paleoseawater Mg/Ca ratios. The Mg/Ca record also highlights that deep ocean temperatures can vary independently and unexpectedly from ice volume changes, which can lead to misinterpretations of the δ18O record.

ice volume
benthic foraminifera
ocean cooling
paleotemperature


Impacts of the Cretaceous Terrestrial Revolution and KPg Extinction on Mammal Diversification

Abstract: Molecular phylogenetic analysis, calibrated with fossils, resolves the time frame of the mammalian radiation. Previous analyses of relations, divergence times, and diversification patterns among extant mammalian families have relied on supertree methods and local molecular clocks. We constructed a molecular supermatrix for mammalian families and analyzed these data with likelihood-based methods and relaxed molecular clocks. Phylogenetic analyses resulted in a robust phylogeny with better resolution than phylogenies from supertree methods. Relaxed clock analyses support the long-fuse model of diversification and highlight the importance of including multiple fossil calibrations that are spread across the tree. Molecular time trees and diversification analyses suggest important roles for the Cretaceous Terrestrial Revolution and Cretaceous-Paleogene (KPg) mass extinction in opening up ecospace that promoted interordinal and intraordinal diversification, respectively. By contrast, diversification analyses provide no support for the hypothesis concerning the delayed rise of present-day mammals during the Eocene Period.

cretaceous terrestrial revolution
phylogeny
placentalia


A toothless dwarf dolphin (Odontoceti: Xenorophidae) points to explosive feeding diversification of modern whales (Neoceti)

Abstract: Toothed whales (Odontoceti) are adapted for catching prey underwater and possess some of the most derived feeding specializations of all mammals, including the loss of milk teeth (monophyodonty), high tooth count (polydonty), and the loss of discrete tooth classes (homodonty). Many extant odontocetes possess some combination of short, broad rostra, reduced tooth counts, fleshy lips, and enlarged hyoid bones—all adaptations for suction feeding upon fishes and squid. We report a new fossil odontocete from the Oligocene (approx. 30 Ma) of South Carolina (Inermorostrum xenops, gen. et sp. nov.) that possesses adaptations for suction feeding: toothlessness and a shortened rostrum (brevirostry). Enlarged foramina on the rostrum suggest the presence of enlarged lips or perhaps vibrissae. Phylogenetic analysis firmly places Inermorostrum within the Xenorophidae, an early diverging odontocete clade typified by long-snouted, heterodont dolphins. Inermorostrum is the earliest obligate suction feeder within the Odontoceti, a feeding mode that independently evolved several times within the clade. Analysis of macroevolutionary trends in rostral shape indicate stabilizing selection around an optimum rostral shape over the course of odontocete evolution, and a post-Eocene explosion in feeding morphology, heralding the diversity of feeding behaviour among modern Odontoceti.


Bayesian Inference of Sampled Ancestor Trees for Epidemiology and Fossil Calibration

Abstract: Phylogenetic analyses which include fossils or molecular sequences that are sampled through time require models that allow one sample to be a direct ancestor of another sample. As previously available phylogenetic inference tools assume that all samples are tips, they do not allow for this possibility. We have developed and implemented a Bayesian Markov Chain Monte Carlo (MCMC) algorithm to infer what we call sampled ancestor trees, that is, trees in which sampled individuals can be direct ancestors of other sampled individuals. We use a family of birth-death models where individuals may remain in the tree process after sampling, in particular we extend the birth-death skyline model [Stadler et al., 2013] to sampled ancestor trees. This method allows the detection of sampled ancestors as well as estimation of the probability that an individual will be removed from the process when it is sampled. We show that even if sampled ancestors are not of specific interest in an analysis, failing to account for them leads to significant bias in parameter estimates. We also show that sampled ancestor birth-death models where every sample comes from a different time point are non-identifiable and thus require one parameter to be known in order to infer other parameters. We apply our phylogenetic inference accounting for sampled ancestors to epidemiological data, where the possibility of sampled ancestors enables us to identify individuals that infected other individuals after being sampled and to infer fundamental epidemiological parameters. We also apply the method to infer divergence times and diversification rates when fossils are included along with extant species samples, so that fossilisation events are modelled as a part of the tree branching process. Such modelling has many advantages as argued in the literature. The sampler is available as an open-source BEAST2 package (https://github.com/CompEvol/sampled-ancestors).

tree
mcmc
diversification rate
fossil taxa
bdss


The species taxonomy of the sauropodomorph dinosaurs from the Löwenstein Formation (Norian, Late Triassic) of Germany

Abstract: The species taxonomy of the sauropodomorph dinosaurs from the Löwenstein Formation of Germany is examined. Previous work has classified these into two taxa: Sellosaurus gracilis from a number of localities and the widespread Plateosaurus engelhardti from a single monospecific accumulation in the Löwenstein Formation, near the town of Trossingen. The current hypodigm of Sellosaurus gracilis is found to contain a substantial amount of variation. This includes differences in the dentition, structure of the skull, composition of the sacrum and the structure of the caudal vertebrae and pelvis. This variation was analysed using a specimen–based parsimony analysis of the sauropodomorphs from the Löwenstein Formation. It was found that two discrete taxa comprise the current hypodigm of Sellosaurus. The more common of these two is a plesiomorphic form for which the correct name is Efraasia minor comb. nov. The less common form (which includes the holotype of Sellosaurus gracilis) is found to share a number of synapomorphies with Plateosaurus engelhardti and is placed in this genus as Plateosaurus gracilis

species taxonomy
sauropodomorph dinosaur
germany
sellosaurus gracilis


Principal component analysis as an alternative treatment for morphometric characters: phylogeny of caseids as a case study

Abstract: In a recent study, the phylogeny of Caseidae (a herbivorous family of Palaeozoic synapsids belonging to the paraphyletic grade known as pelycosaurs) was analysed with a dataset employing more than three hundred continuous morphological characters in an effort to follow the principles of total evidence. Continuous characters are a source of great debate, with disagreements surrounding their suitability for and treatment in phylogenetic analysis. A number of shortcomings were identified in the handling of continuous characters in this study of caseids, including the use of gap weighting to discretize the characters and potential issues with redundancy and character non‐independence. Therefore, an alternative treatment for these characters is suggested here. First, rather than using gap weighting, the continuous characters were analysed in the program TNT, in which the raw values can be treated as continuous rather than discrete. Second, prior to the phylogenetic analysis, the continuous characters were subjected to a log‐ratio principal component analysis, and then the principal components were included in the character matrix rather than the raw ratios. Analysing the original data in TNT produced little difference in the results, but using the principal components as continuous characters resulted in alternative positions for Caseopsis agilis, Ennatosaurus tecton and Caseoides sanangeloensis. The differences are judged to be due to the reduced redundancy of the characters, the smaller number of principal components not overwhelming the discrete characters and the use of a scaling method which allows principal components with a higher variance to have a greater influence on the analysis. The positions of highly fragmentary fossils depended heavily on the method used to treat the missing characters in the principal component analysis, and so the method proposed here is not recommended for analysing very incomplete taxa.

alternative treatment
caseid
principal component analysis


Morphology and Evolutionary Significance of the Atlas-Axis Complex in Varanopid Synapsids

Abstract: The atlas-axis complex has been described in few Palaeozoic taxa, with little effort being placed on examining variation of this structure within a small clade. Most varanopids, members of a clade of gracile synapsid predators, have well preserved atlas-axes permitting detailed descriptions and examination of morphological variation. This study indicates that the size of the transverse processes on the axis and the shape of the axial neural spine vary among members of this clade. In particular, the small mycterosaurine varanopids possess small transverse processes that point posteroventrally, and the axial spine is dorsoventrally short, with a flattened dorsal margin in lateral view. The larger varanodontine varanopids have large transverse processes with a broad base, and a much taller axial spine with a rounded dorsal margin in lateral view. Based on outgroup comparisons, the morphology exhibited by the transverse processes is interpreted as derived in varanodontines, whereas the morphology of the axial spine is derived in mycterosaurines. The axial spine anatomy of Middle Permian South African varanopids is reviewed and our interpretation is consistent with the hypothesis that at least two varanopid taxa are present in South Africa, a region overwhelmingly dominated by therapsid synapsids and parareptiles.

atlas-axis complex
spine
lateral view
base
morphology


Avian tail ontogeny, pygostyle formation, and interpretation of juvenile Mesozoic specimens

Abstract: The avian tail played a critical role in the evolutionary transition from long- to short-tailed birds, yet its ontogeny in extant birds has largely been ignored. This deficit has hampered efforts to effectively identify intermediate species during the Mesozoic transition to short tails. Here we show that fusion of distal vertebrae into the pygostyle structure does not occur in extant birds until near skeletal maturity, and mineralization of vertebral processes also occurs long after hatching. Evidence for post-hatching pygostyle formation is also demonstrated in two Cretaceous specimens, a juvenile enantiornithine and a subadult basal ornithuromorph. These findings call for reinterpretations of Zhongornis haoae, a Cretaceous bird hypothesized to be an intermediate in the long- to short-tailed bird transition, and of the recently discovered coelurosaur tail embedded in amber. Zhongornis, as a juvenile, may not yet have formed a pygostyle, and the amber-embedded tail specimen is reinterpreted as possibly avian. Analyses of relative pygostyle lengths in extant and Cretaceous birds suggests the number of vertebrae incorporated into the pygostyle has varied considerably, further complicating the interpretation of potential transitional species. In addition, this analysis of avian tail development reveals the generation and loss of intervertebral discs in the pygostyle, vertebral bodies derived from different kinds of cartilage, and alternative modes of caudal vertebral process morphogenesis in birds. These findings demonstrate that avian tail ontogeny is a crucial parameter specifically for the interpretation of Mesozoic specimens, and generally for insights into vertebrae formation.

pygostyle formation
mesozoic specimen
extant bird
avian tail ontogeny


First fossil records of the tholichthys larval stage of butterfly fishes (Perciformes, Chaetodontidae), from the Oligocene of Europe

Abstract: The first fossils of the tholichthys larval stage of a chaetodontid from the lower Oligocene (Rupelian, Fish Shales; about 30.1 MYA) of Frauenweiler (Baden-Wu ¨rttemberg, S Germany) are described, along with two less well-preserved probable tholichthys from the lower Oligocene Menilite-Formation (IPM3, 30-29 MYA and IPM4A, 29-28 MYA) of Przemys ´l (Outer Carpathians, SE Poland). The fossils are compared with tholichthys larvae of the extant genus of Chaetodontidae to which they are most similar, namely Chaetodon. The German specimens are identified as tholichthys larvae by the plate-like expansions of the supracleithrum and posttemporal that extend posteriorly well behind the head and by an expanded preopercle with a large posterior spine; these bones, and the frontals and supraoccipital, are distinctively rugose. The Polish specimen from IPM3 has similar features so it is safe to assume that it also is a chaetodontid tholichthys, whereas the specimen from IPM4A is so poorly preserved that it can only very tentatively be referred to the Chaetodontidae. The occurrence of tholichthys larvae prompts reconsideration of the paleoenvironmental situation at their respective fossil sites.

tholichthy larval stage
chaetodontidae
oligocene


A new approach using high-resolution computed tomography to test the buoyant properties of chambered cephalopod shells

Abstract:
Abstract.
 The chambered shell of modern cephalopods functions as a buoyancy apparatus, allowing the animal to enter the water column without expending a large amount of energy to overcome its own weight. Indeed, the chambered shell is largely considered a key adaptation that allowed the earliest cephalopods to leave the ocean floor and enter the water column. It has been argued by some, however, that the iconic chambered shell of Paleozoic and Mesozoic ammonoids did not provide a sufficiently buoyant force to compensate for the weight of the entire animal, thus restricting ammonoids to a largely benthic lifestyle reminiscent of some octopods. Here we develop a technique using high-resolution computed tomography to quantify the buoyant properties of chambered shells without reducing the shell to ideal spirals or eliminating inherent biological variability by using mathematical models that characterize past work in this area. This technique has been tested on Nautilus pompilius and is now extended to the extant deep-sea squid Spirula spirula and the Jurassic ammonite Cadoceras sp. hatchling. Cadoceras is found to have possessed near-neutral to positive buoyancy if hatched when the shell possessed between three and five chambers. However, we show that the animal could also overcome degrees of negative buoyancy through swimming, similar to the paralarvae of modern squids. These calculations challenge past inferences of benthic life habits based solely on calculations of negative buoyancy. The calculated buoyancy of Cadoceras supports the possibility of planktonic dispersal of ammonite hatchlings. This information is essential to understanding ammonoid ecology as well as biotic interactions and has implications for the interpretation of geochemical data gained from the isotopic analysis of the shell.

high-resolution
tomography
buoyant property


A small podocnemidoid (Pleurodira, Pelomedusoides) from the Late Cretaceous of Brazil, and the innervation and carotid circulation of side‐necked turtles

Abstract: Pleurodires are less diverse than cryptodires, together forming the two major lineages of crown turtles. Their fossil record, however, is rich. A particularly large number of fossil pleurodires, many belonging to the Podocnemidoidae, has been recovered from the Upper Cretaceous Bauru Group outcrops of south‐central Brazil. Herein we describe an additional pleurodire from this region, Amabilis uchoensis gen. et sp. nov., based on a partially preserved skull. A. uchoensis is recognized as belonging to the Podocnemidoidae by the small entrance to the antrum postoticum and completely developed cavum pterygoidei, being unique among other non‐podocnemidid podocnemidoids for its medially open fenestra postotica and absent basioccipital–opisthotic contact. Our cladistic analysis places A. uchoensis as a sister taxon to Hamadachelys + other podocnemidoids. We further explore the neuroanatomy of side‐necked turtles with the aid of micro‐computed tomography of specimens of the main pleurodiran lineages. Our data shed light on the different carotid circulation patterns in pleurodires, and we propose new phylogenetic characters to describe the neuroanatomical variation of the group. Optimization of these characters shows two independent acquisitions of a foramen for the palatal branch of the carotid in chelids and podocnemidoids, and a unique loss of the vidian nerve canal in chelids, in turtles in general.


High-precision time-space correlation through coupled apatite and zircon tephrochronology: An example from the Permian-Triassic boundary in South China

Abstract: Accurate and precise dating of individual volcanogenic beds that spread across multiple sedimentary successions is a powerful tool to untangle stratigraphic age contradictions, since these horizons are deposited synchronously. In this study, we show that combining apatite chemistry with zircon age, Th/U ratio, and Hf isotope composition leads to reliable lateral correlation of volcanic horizons across sections representing disparate biological, chemical, and physical paleoenvironments. We correlate two volcanogenic horizons across six sedimentary sections straddling the Permian-Triassic boundary (PTB) in the Nanpanjiang Basin (South China), including the last Permian bed below the unconformity in shallow-water sections of the Luolou Platform. We place the PTB in our sections at the marked lithological change in order to avoid the difficulties that arise from the diachronism of the index conodont Hindeodus parvus, the first occurrence of which defines the PTB at the Global Stratotype Section and Point at Meishan. Our new data demonstrate that these volcanogenic beds are contemporaneous and cogenetic, allowing us to pool high-precision U-Pb zircon ages from the same horizon across several sections, and dating the last Permian volcanic event in this basin at 252.048 ± 0.033 Ma. We show that the mineral chemistry of apatite and zircon of intra- and interbasin-wide volcanogenic beds provides tie points against which biozones, carbon isotopes, astronomic cycles, and geomagnetic polarity time series can be stringently tested.

apatite
permian-triassic boundary
south china


Paleo-ocean redox environments of the Upper Ordovician Wufeng and the first member in lower Silurian Longmaxi formations in the Jiaoshiba area, Sichuan Basin

Abstract: A study of paleo-ocean redox environments is important for understanding the deposition of black shale and has practical implications for shale gas exploration. Here, we selected a total of 52 shale samples from JY1 Well, the first shale gas well of commercial exploitation in China, to analyze the redox conditions of Upper Ordovician Wufeng (O3w) and the first member in lower Silurian Longmaxi shale (S1l1) in the Jiaoshiba area. Abundant pyrite framboids are observed in these units, with average framboid diameters ranging from 3.1 to 4.7 μm and maximum diameter about 10 μm. Analyses of redox-sensitive trace elements suggest the redox environment has evolved from an anoxic condition in the bottom of Member A to a dysoxic condition in the top of Member A, and to a dysoxic–oxic environment in Members B and C. Graptolite and radiolarian are discovered in these shale samples, indicating an oxygenated seafloor, which seems to be contradictory to the results from pyrite framboids and redox-sensitive trace elemen...

upper ordovician wufeng
sichuan basin
paleo-ocean redox environment


The Ichnogenus Undichna, With Examples From The Permian Of The Falkland Islands

Abstract: Abundant, well‐preserved and variable species of Undichna are described from the Permian of the Falkland Islands. The environment is considered to be non‐marine and the traces are associated with turbidite and rhythmite deposits. There are strong similarities between the Undichna and other ichnogenera of the Falkland Islands and those of the Eastern Cape Province of South Africa, thus strengthening the view that the missing eastern end of the Permian Karoo Basin is present in the Falklands. Undichna binaU. insolentia occur associated within glacially influenced rhythmite and turbidite facies of a non‐marine basin in the Cantera Formation, Camilla Creek, East Falkland. U. quina isp. nov. occurs on Sea Lion Island and is associated with thin (mm–cm scale) graded interbeds between thicker amalgamated sandstones in a sequence deposited by density currents derived from a delta feeding the same non‐marine basin. The elements that comprise Undichna traces are (1) single sinusoidal grooves, (2) paired sinusoidal grooves, (3) broad shallow grooves, (4) repeated arcuate imprints, (5) irregular grooves, (6) striated brush‐like imprints. A distinct, repeated morphology is only produced by a constant activity of the tracemaker (generally a fish). Irregular activity (e.g. acceleration, sharp turns) or current action produces non‐constant morphology, lacking the defining regularity of the ichnogenus Undichna. Such irregular forms can frequently be identified as a modified expression of a described ichnospecies, but morphologically do not fall within the definition of the ichnospecies. It is suggested that rather than create new names they should be referred to as ‘cf. Undichna isp.’ (irregular form).

ichnogenus undichna
permian
falkland islands