30 September 2019, Volume 30 Issue 3

    

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  Contents Vol. 30 No. 3 September 2019

  Advances in Polar Science. 2019, 30(3): 0-0.

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  Advances in Polar Science
  Contents Vol. 30 No. 3 September 2019
  Special Issue : Geology and paleontology of the James Ross Basin, Antarctic Peninsula
  
  Foreword
  Reviews
  Mesozoic and Cenozoic microbiotas from the eastern Antarctic Peninsula: adaptation to a changing palaeoenvironment
  Cecilia R. AMENÁBAR, Andrea CARAMÉS, Susana ADAMONIS, Ana DOLDAN, Gabriel MACEIRAS & Andrea CONCHEYRO
  Paleobiological significance of the James Ross Basin
  J. Alistair CRAME
  The fossil record of durophagous predation in the James Ross Basin over the last 125 million years
  Elizabeth M. HARPER, J. Alistair CRAME & Alice M PULLEN
  Cretaceous Antarctic plesiosaurs: stratigraphy, systematics and paleobiogeography
  José Patricio O’GORMAN, Rodrigo OTERO, Marcelo REGUERO & Zulma GASPARINI
  Late Cretaceous non-avian dinosaurs from the James Ross Basin, Antarctica: description of new material, updated synthesis, biostratigraphy, and paleobiogeography
  Matthew C. LAMANNA, Judd A. CASE, Eric M. ROBERTS, Victoria M. ARBOUR, Ricardo C. ELY, Steven W. SALISBURY, Julia A. CLARKE, D. Edward MALINZAK, Abagael R. WEST & Patrick M. O’CONNOR
  The fossil record of birds from the James Ross Basin, West Antarctica
  Carolina ACOSTA HOSPITALECHE, Piotr JADWISZCZAK, Julia A. CLARKE & Marcos CENIZO
  The fossil record of Antarctic land mammals: commented review and hypotheses for future research
  Javier N. GELFO, Francisco J. GOIN, Nicolás BAUZÁ & Marcelo REGUERO
  Eocene Antarctica: a window into the earliest history of modern whales
  Mónica R. BUONO, R. Ewan FORDYCE, Felix G. MARX, Marta S. FERNÁNDEZ & Marcelo A. REGUERO
  Article
  Late Maastrichtian–Paleocene chronostratigraphy from Seymour Island, James Ross Basin, Antarctic Peninsula: Eustatic controls on sedimentation
  Manuel MONTES, Elisabet BEAMUD, Francisco NOZAL & Sergio SANTILLANA
  Trend
  Antarctic Paleontological Heritage: Late Cretaceous–Paleogene vertebrates from Seymour (Marambio) Island, Antarctic Peninsula
  Marcelo A. REGUERO
  Inviting contributions to Special Issues in 2020
  
  Cover picture: View of central Seymour Island, looking NE; the prominent scarp in the centre-foreground marks the K/Pg boundary. The gentle easterly regional dip reveals a 1000 m + thick sedimentary succession from the latest Cretaceous (Maastrichtian) to late Eocene on the horizon. The image in the top left hand corner shows a Middle Eocene shell bed, La Meseta Formation, Seymour Island (paper by J. Alistair Crame, page 186).
  
Foreword
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  Foreword

  Carolina Acosta Hospitaleche, Javier N. Gelfo, J. Alistair Crame

  Advances in Polar Science. 2019, 30(3): 164-164.

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  The geological and paleontological potential of the James Ross Basin, located at the northeastern tip of the Antarctic Peninsula, seems inexhaustible. A late Mesozoic–early Cenozoic sedimentary succession nearly 7 km thick is exposed within the basin, and numerous fossiliferous levels make it possible to carry out fundamental research into the evolution of both marine and continental floras and faunas at this high paleolatitude locality. This situation, linked to the spirit of scientific collaboration that governs Antarctica thanks to the Antarctic Treaty System, has resulted in innumerable important scientific contributions to date. In this Special Issue, “Geology and Paleontology of the James Ross Basin, Antarctic Peninsula”, the essence of the Antarctic Treaty is honored and celebrated. Ten original scientific works are presented by researchers from ten different countries (Argentina, Australia, Belgium, Canada, Chile, New Zealand, Poland, Spain, UK, USA) in a collaboration that highlights the current state of knowledge of this classic geological site, addressing both highly relevant questions and opening exciting new lines of inquiry for Antarctic Earth Sciences. The contributions presented here have been divided into the following categories: eight Reviews, one Article, and one Trend.
Reviews
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  Mesozoic and Cenozoic microbiotas from eastern Antarctic Peninsula: adaptation to a changing palaeoenvironment

  Cecilia R. AMENÁBAR, Andrea CARAMÉS, Susana ADAMONIS, Ana DOLDAN, Gabriel MACEIRAS, Andrea CONCHEYRO

  Advances in Polar Science. 2019, 30(3): 165-185. https://doi.org/10.13679/j.advps.2019.0017

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  A compiled selected literature on some groups of microfossils of the Mesozoic and Cenozoic of the James Ross Basin, eastern Antarctic Peninsula, is presented here, in order to show how the microbiota has been modified over time, triggered by environmental changes. The analyzed microfossils consist of palynomorphs (mostly pollen grains, spores, and dinoflagellate cysts), foraminifers and bryozoans. Dinoflagellate cysts and pollen-spores have been recorded in Jurassic to Pleistocene sedimentary outcrops. Dinoflagellate cysts proved to be good indicators for productivity and/or nutrient availability, surface water temperature and chemistry, the position of ancient shorelines and paleoceanographic trends. Pollen and spores allowed reconstruction of floral community and thus characterization of the climate that prevailed on the continent. Foraminifera, recovered from the Lower Cretaceous to the Pleistocene sedimentary rocks, provided information about the bathymetry, showing different marine settings (e.g., coastal, inner neritic, outer neritic, upper bathyal) in different localities. The bryozoan record is restricted to the Cenozoic. Their colonial growth-forms reflect several environmental conditions such as shallow waters with a low rate of sedimentation, hard substrate and moderate or strong current action for the analyzed localities. The study of the Antarctic ecosystems based on the fossil microbiota and their response to the climate and the continental configuration changes, allowed understanding of the composition and dynamics of the polar environments, which have an important role in the Earth climate.
  
  
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  Paleobiological significance of the James Ross Basin

  J. Alistair CRAME

  Advances in Polar Science. 2019, 30(3): 186-198. https://doi.org/10.13679/j.advps.2018.0047

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  The extensive Late Mesozoic–Early Cenozoic sedimentary succession exposed within the James Ross Basin, Antarctica has huge potential to enhance paleobiological investigations into both the marine and terrestrial fossil records. In excess of 7 km in total thickness and spanning the Early Cretaceous (Aptian)–Late Eocene in age, it represents an invaluable high-latitude (~65°S) site for comparison with lower latitude, tropical ones in an essentially greenhouse world. The Early Cretaceous (Aptian–Albian) sequence is deep-water but there are indications of shallowing to inner shelf depths in both the Turonian and Coniacian stages. The first prolific shallow-water marine fauna occurs in the Santonian–Campanian Santa Marta Formation and this is followed by repeated occurrences through the later Campanian, Maastrichtian, Danian and Middle Eocene (Lutetian). In this study an attempt has been made to compare these Antarctic faunas directly with the well-known ones of the same age from the US Gulf Coast. Detailed comparisons made for three time slices, Late Maastrichtian, Danian and Middle Eocene, indicate that the Antarctic is characterised by both low taxonomic diversity and high levels of endemism. The James Ross Basin is providing important evidence to indicate that the highest southern latitudes have always been characterised by a distinctive temperate biota, even on a pre-glacial Earth. The roots of at least some elements of the modern Southern Ocean biota can be traced back to a Late Mesozoic–Early Cenozoic austral realm.
  
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  The fossil record of durophagous predation in the James Ross Basin over the last 125 million years

  Elizabeth M. HARPER, J. Alistair CRAME, Alice M PULLEN

  Advances in Polar Science. 2019, 30(3): 199-209. https://doi.org/10.13679/j.advps.2019.0001

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  We review the evidence for predation of shelly benthic prey over 125 million years of earth history in the James Ross Basin, Antarctica (~65°S). Although poor in the Early Cretaceous lower parts of the sequence, which represent essentially deeper water facies, evidence for both potential crushers and drillers becomes more apparent in the Santonian–Campanian Santa Marta Formation, and by the Maastrichtian López de Bertodano Formation there is an extensive fossil record of drill holes attributable to naticid gastropods, and some evidence of crushing by decapods crustaceans and possibly other taxa too. This continues at a similar level of intensity across the K/Pg boundary into the Danian Sobral Formation, but is less well constrained in the latest Paleocene–Early Eocene. The most extensive record of predation occurs in the Middle Eocene section of the La Meseta Formation on Seymour Island which also records the highest levels of benthic diversity within the entire basin. This key section is providing some important new evidence to suggest that the rate of acceleration of benthic predation intensity through the Late Mesozoic–Early Cenozoic in the polar regions may be similar to that seen in lower latitude regions. Predator–prey interaction was a key factor in the evolution of polar marine faunas too.
  
  
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  Cretaceous Antarctic plesiosaurs: stratigraphy, systematics and paleobiogeography

  Jose Patricio O'GORMAN, Rodrigo OTERO, Marcelo REGUERO, Zulma GASPARINI

  Advances in Polar Science. 2019, 30(3): 210-227. https://doi.org/10.13679/j.advps.2018.0049

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  The last twenty million years (Maastrichtian–Santonian) of Southern Hemisphere plesiosaur history is especially well recorded in the Weddellian Province (Patagonia; Western Antarctica and New Zealand). The oldest Late Cretaceous plesiosaurs, two specimens referred to Polycotylidae indet., come from the Santonian levels of the Santa Marta Formation, while the oldest elasmosaurids come from the lower Campanian of the same formation. In the lower Maastrichtian of the Snow Hill Island Formation the non-aristonectine elasmosaurid Vegasaurus molyi is recorded together with other non-diagnosable elasmosaurid specimens, but no aristonectines are present. Aristonectines appears in the Antarctic record in the upper Maastrichtian of the López de Bertodano Formation and are represented by Morturneria and cf. Aristonectes. The specimens from the upper Campanian previously referred to Aristonectinae indet. are referred to Elasmosauridae indet., shortening the temporal record of Aristonectinae in Antarctica. Therefore aristonectines appears in the Antarctic record in the upper Maastrichtian of the López de Bertodano Formation and are represented by Morturneria and cf. Aristonectes. The Antarctic Cretaceous elasmosaurids show a paleobiogeographic connection with South America and New Zealand (Weddellian Province). This connection is indicated by the shared presence of the Aristonectinae Kaiwhekea katiki (New Zealand) and Aristonectes (Argentina and Chile). Recent phylogenetic analysis recovered the aristonectines within the Weddellonectia clade, which includes the aristonectines and the non-aristonectines Vegasaurus molyi (Isla Vega, Antarctica); Kawanectes lafquenianum (Argentina); Morenosaurus stocki and Aphrosaurus furlongi (California). Among the Weddellonectia, the aristonectines show a relatively large body size and extremely derived features and probably occupied a trophic niche that differed from the trophic niche of other elasmosaurids. By way of contrast Kawanectes lafquenianum is an extremely small body-sized elasmosaurid restricted to marginal marine (probably estuarine) environments. Therefore the Weddellonectia show high morphological and probably high ecological diversity.
  
  
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  Late Cretaceous non-avian dinosaurs from the James Ross Basin, Antarctica: description of new material, updated synthesis, biostratigraphy, and paleobiogeography

  Matthew C. LAMANNA, Judd A. CASE, Eric M. ROBERTS, Victoria M. ARBOUR, Ricardo C. ELY, Steven W. SALISBURY, Julia A. CLARKE, D. Edward MALINZAK, Abagael R. WEST, Patrick M. O’CONNOR

  Advances in Polar Science. 2019, 30(3): 228-250. https://doi.org/10.13679/j.advps.2019.0007

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  Although the fossil record of non-avian dinosaurs from the Cretaceous of Antarctica is the poorest of any continent, fossils representing at least five major taxonomic groups (Ankylosauria, early-diverging Ornithopoda, Hadrosauridae, Titanosauria, and Theropoda) have been recovered. All come from Upper Cretaceous (Coniacian–Maastrichtian) marine and nearshore deposits belonging to the Gustav and Marambio groups of the James Ross Basin at the northern tip of the Antarctic Peninsula. The majority of these finds have come from the Campanian–Maastrichtian Snow Hill Island and López de Bertodano formations of James Ross and Vega islands. Given the rarity of Antarctic Cretaceous non-avian dinosaurs, discoveries of any fossils of these archosaurs, no matter how meager, are of significance. Here we describe fragmentary new ornithischian (ankylosaur and ornithopod) material from the upper Campanian–lower Maastrichtian Cape Lamb Member of the Snow Hill Island Formation and the Maastrichtian Sandwich Bluff Member of the López de Bertodano Formation. One of these specimens is considered to probably pertain to the holotypic individual of the early-diverging ornithopod Morrosaurus antarcticus. We also provide an up-to-date synthesis of the Late Cretaceous non-avian dinosaur record of the James Ross Basin and analyze the biostratigraphic occurrences of the various finds, demonstrating that most (including all named taxa and all reasonably complete skeletons discovered to date) occur within a relatively condensed temporal interval of the late Campanian to early Maastrichtian. Most or all James Ross Basin dinosaurs share close affinities with penecontemporaneous taxa from Patagonia, indicating that at least some continental vertebrates could disperse between southern South America and Antarctica during the final stages of the Mesozoic.
  
  
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  The fossil record of birds from the James Ross Basin, West Antarctica

  Carolina ACOSTA HOSPITALECHE, Piotr JADWISZCZAK, Julia A. CLARKE, Marcos CENIZO

  Advances in Polar Science. 2019, 30(3): 251-273. https://doi.org/10.13679/j.advps.2019.0014

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  The fossil record of birds from Antarctica is concentrated in the James Ross Basin, located in north-east of the Antarctic Peninsula. Birds are here represented by an extensive Paleogene record of penguins (Sphenisciformes) and Cretaceous–Paleogene record of Anseriformes, followed by other groups with a minor representation (Procellariiformes, Falconiformes, and Pelagornithidae), and others previously assigned controversially to “Ratites”, Threskiornithidae, Charadriiformes, Gruiformes, Phoenicopteriformes, and Gaviiformes. We provide a complete update of these records, commenting on the importance of some of these remains for the evolution of the major clades.
  
  
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  The fossil record of Antarctic land mammals: commented review and hypotheses for future research

  Javier N. GELFO, Francisco J. GOIN, Nicolás BAUZÁ, Marcelo REGUERO

  Advances in Polar Science. 2019, 30(3): 274-292. https://doi.org/10.13679/j.advps.2019.0021

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  The fossil record of terrestrial mammals in Antarctica is temporally and geographically constrained to the Eocene outcrops of La Meseta and Submeseta formations in Seymour (Marambio) Island in West Antarctica. The faunal assemblage indicates a clear South American imprint since all the groups have a close phylogenetic relationship with Cretaceous and Paleogene mammals from Patagonia. Despite the presence of several mammalian taxonomic groups: Dryolestida, Gondwanatheria, Eutheria and Metatheria, the presence of other major mammalian taxa should be expected and will probably be confirmed by new findings. Placental mammals with an inferred body mass between 10 to 400 kg in size, are represented by xenarthrans, and two groups of the so called South American native ungulates: Astrapotheria and Litopterna. The Metatheria are the smaller (less than 1 kg) and most abundant components of the fauna. Marsupials are represented by derorhynchid ameridelphians, several microbiotherian australidelphians (both microbiotheriids and woodburnodontids), and ?glasbiid prepidolopod and polydolopid polydolopimorphians. Plus, there are remains of several mammalian teeth of indeterminate phylogenetic affinities. The present knowledge of the Southern Hemisphere mammalian evolution and paleogeographic change through time, indicates that Antarctica played a major role for land mammals, at least since the Jurassic. The actual representation of Paleogene terrestrial mammals in Antarctica is most probably biased, as all the evidence indicates that australosphenidan mammals should be present in this continent since the Jurassic.
  
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  Eocene Antarctica: a window into the earliest history of modern whales

  Mónica R. BUONO, R. Ewan FORDYCE, Felix G. MARX, Marta S. FERNÁNDEZ, Marcelo A. REGUERO

  Advances in Polar Science. 2019, 30(3): 293-302. https://doi.org/10.13679/j.advps.2019.0005

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  The Eocene–Oligocene Southern Ocean is thought to have played a major role in cetacean evolution. Yet, fossils from its heart – Antarctica – are rare, and come almost exclusively from the Eocene La Meseta and Submeseta formations of Marambio (Seymour) Island. Here, we provide a summary and update of this crucial fossil assemblage, and discuss its relevance in the broader context of cetacean evolution. To date, Eocene specimens from Antarctica include basilosaurids, a group of archaic stem cetaceans that had already fully adapted to life in water; and the archaic toothed mysticete Llanocetus , the second oldest crown cetacean on record (ca. 34 Ma). This Eocene co-occurrence of stem and crown cetaceans is highly unusual, and otherwise only observed in Peru. Though related, at least some of the Antarctic species appear to be different from, and notably larger than their Peruvian counterparts, suggesting an early differentiation of the high latitude cetacean fauna.
  
  
Articles
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  Late Maastrichtian–Paleocene chronostratigraphy from Seymour Island, James Ross Basin, Antarctic Peninsula: Eustatic controls on sedimentation

  Manuel MONTES, Elisabet BEAMUD, Francisco NOZAL, Sergio SANTILLANA

  Advances in Polar Science. 2019, 30(3): 303-327. https://doi.org/10.13679/j.advps.2018.0045

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  The Paleocene (66–56 Ma) was a critical time interval for understanding the geological history in high palaeolatitudes after the end of Cretaceous event (recovery from mass extinction, palaeoclimate, global sea level changes, among others). The sedimentary succession from Seymour Island (Antarctic Peninsula) provides key reference material from this important phase of the early Cenozoic. A detailed age model is proposed for the López de Bertodano Formation (LBF), Sobral Formation (SF) and Cross Valley–Wiman Formation (CVWF) based on a new magnetostratigraphic section which integrates previous dinoflagellate cyst biostratigraphy, Iridium anomaly (K-Pg boundary), U-Pb zircon dating (airfall tuff) and strontium isotope values from macrofossils. The new composite magnetostratigraphic section, which includes the Cretaceous–Paleogene boundary, has been correlated to the GPTS from C29r up to C24r. The top of the LBF is confirmed as latest Maastrichtian to earliest Danian (~65.4 Ma) in age. The overlying SF is mostly Danian in age (~65.2– ~63 Ma) and CVWF is Selandian–Thatenian (~61.3–56.9 Ma). LBF, SF and CVWF are unconformity-bounded units (alloformations) that record the geological evolution of the James Ross Basin during a period of relative decreasing tectonism but coeval with volcanic activity. Unconformity based internal units have been recognized, dividing each formation into allomembers (LBF: Molluscan and Cenozoic; SF: A, B and C; CVWF: Díaz, Arañado, Bahía Pingüino). The new age model allows correlation of base-level changes with eustatic sea-level fluctuations. The bases of the SF and CVWF are correlated with the 65.3 and 61.5 Ma sea level lowstands.
  
  
Trends
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  Antarctic Paleontological Heritage: Late Cretaceous–Paleogene vertebrates from Seymour (Marambio) Island, Antarctic Peninsula

  Marcelo A. REGUERO

  Advances in Polar Science. 2019, 30(3): 328-355. https://doi.org/10.13679/j.advps.2019.0015

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  Antarctica has significant environmental, scientific, historic, and intrinsic values, all of which are worth protecting into the future. This continent has a discrete number of places of scientific interest that exhibit great potential as natural heritage sites; its geodiversity is of fundamental importance to scientific values of the continent, and the pursuit of geological and paleontological knowledge has had a strong influence on its historical values. Seymour Island was once called the ‘Rosetta Stone’ of Southern Hemisphere paleobiology, because this small island provides the most complete and richly fossiliferous Late Cretaceous–Paleogene sequence in Antarctica. In particular, fossil vertebrates form part of the evidence used in reconstructing the history of life on Antarctica. Paleontological heritage is considered a subset of geo-heritage that embodies both natural and historical components which has received only indirect recognition. Seymour Island is an outstanding paleontological area with high heritage value of its Late Cretaceous/Paleogene vertebrates and should be considered for geo-conservation and protection. This paper reviews vertebrate fossil occurrences and outcrops on Seymour Island and discusses some threats to these fossil sites.
  
Annoucements
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  Inviting contributions to Special Issue in 2020

  Advances in Polar Science. 2019, 30(3): 356-356.

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  We would like to invite you to submit manuscripts to the special issue “Polar Regions in the Global Climate System” to be published in June of 2020. For more details, please visit the APS's websites: www.aps-polar.org.
  The schedule for the special issue “Polar Regions in the Global Climate System” is:
  ·Paper submission deadline: 30 September 2019
  ·Final acceptance deadline: 30 February 2020
  ·Publication: June 2020
  Accepted papers will be published online for open access as soon as authors have returned their proofs and all corrections have been made.