Late Palaeozoic South American pectinids revised: biostratigraphical and palaeogeographical implications

Neves, J.P., Anelli, L.E., Pagani, M.A. & Simões, M.G., 2014. Late Palaeozoic South American pectinids revised: biostratigraphical and palaeogeographical implications. Alcheringa 38 ISSN 0311-5518.

A revision of the late Palaeozoic South American pectinid Heteropecten multiscalptus (Thomas) and the establishment of Heteropecten paranaensis sp. nov. have important implications for the relationship between faunal realms within South America. Late Palaeozoic bivalve faunas occur in three distinct realms in South America: a Central Gondwanic Realm with endemic taxa showing affinities to Australia, New Zealand, South Africa and Namibia, a cold Perigondwanic Realm, and a warm Extragondwanic Realm with tethyan-like affinities similar to faunas of the American Midcontinent. In South America, faunas east of the southern Andes belong to the first two realms and previous interpretations of bivalve faunas suggested biocorrelations with those of the Extragondwanic Realm because they shared the taxon Heteropecten multiscalptus (Thomas). A revision of the Peruvian and Brazilian material does not confirm this. Instead, a re-analysis suggests that two species are present, rather than one: Heteropecten multiscalptus in the Cerro Prieto Formation, Amotape Mountains (Peru; Extragondwanic Realm), and Heteropecten paranaensis sp. nov. in the upper part of the Itararé Group, Paraná Basin (Brazil; Central Gondwanic Realm). Thus, the correlation between the late Palaeozoic faunas of the Central Gondwanic and Extragondwanic Realms in South America can no longer be supported. Heteropecten paranaensis sp. nov. lived in a siliciclastic-dominated, cold, epeiric sea of Brazil and Argentina, and is morphologically similar to some Australian species, whereas the Peruvian H. multiscalptus thrived in the warm seas of the Extragondwanic Realm.

Jacqueline P. Neves [nevesjp.unesp@gmail.com], Instituto de Geociências e Ciências Exatas, Universidade Estadual Paulista, Rio Claro campus, SP, Brazil, 13506-900; Luiz E. Anelli [anelli@usp.br], Instituto de Geociências, Universidade de São Paulo, 05508–080, Brazil; M. Alejandra Pagani, [apagani@mef.org.ar], CONICET-Museo Paleontológico Egidio Feruglio (MEF), U9100GYO, Chubut, Argentina; Marcello, G. Simões [profmgsimoes@gmail.com], Instituto de Biociências, Universidade Estadual Paulista, Botucatu campus, SP, 18618-970, Brazil. Received 19.7.2013; revised 12.11.2013; accepted 19.11.2013     

Palaeoecological insights into the Changhsingian–Induan (latest Permian–earliest Triassic) bivalve fauna at Dongpan,southern Guangxi,South China

Yang, T.L., He, W.H., Zhang, K.X., Wu, S.B., Zhang, Y., Yue, M.L., Wu, H.T. & Xiao, Y.F., November 2015. Palaeoecological insights into the Changhsingian–Induan (latest Permian–earliest Triassic) bivalve fauna at Dongpan, southern Guangxi, South China. Alcheringa 40, xxx–xxx. ISSN 0311-5518.

The Talung Formation (latest Permian) and basal part of Luolou Formation (earliest Triassic) of the Dongpan section have yielded 30 bivalve species in 17 genera. Eight genera incorporating 11 species are systematically described herein, including three new species: Nuculopsis guangxiensis, Parallelodon changhsingensis and Palaeolima fangi. Two assemblages are recognized, i.e., the Hunanopecten exilis–Euchondria fusuiensis assemblage from the Talung Formation and the Claraia dieneri–Claraia griesbachi assemblage from the Luolou Formation. The former is characterized by abundant Euchondria fusuiensis, an endemic species, associated with other common genera, such as Hunanopecten, which make it unique from coeval assemblages of South China. A palaeoecological analysis indicates that the Changhsingian bivalve assemblage at Dongpan is diverse and represented by various life habits characteristic of a complex ecosystem. This also suggests that redox conditions were oxic to suboxic in deep marine environments of the southernmost Yangtze Basin during the late Changhsingian, although several episodes of anoxic perturbations and declines in palaeoproductivity saw deterioratation of local habitats and altered the taxonomic composition or population size of the bivalve fauna.

Tinglu Yang [yang@geology.so], School of Earth Sciences, China University of Geosciences, 388 Lumo Road, Hongshan, Wuhan 430074, PR China; Weihong He* [whzhang@cug.edu.cn] and Kexin Zhang [kx_zhang@cug.edu.cn], State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences, China University of Geosciences, 388 Lumo Road, Hongshan, Wuhan 430074, PR China; Shunbao Wu [shbwu@cug.edu.cn], Yang Zhang [zhangy05@163.com], Mingliang Yue [812182779@qq.com], Huiting Wu [ht_wu415@163.com] and Yifan Xiao [shadowyi@sohu.com], School of Earth Sciences, China University of Geosciences, 388 Lumo Road, Hongshan, Wuhan 430074, PR China.     

Modern and early-middle Holocene shells of the freshwater mollusc Unio, from Çatalhöyük in the Konya Basin, Turkey: preliminary palaeoclimatic implications from molluscan isotope data

Carbon and oxygen isotope ratios in the shells of the freshwater Unio mollusc yield information on the isotopic composition of the water in which the shell was formed, which in turn relates to climatic conditions prevailing during the bivalves’ life span. Here we analysed shells from one modern Unio, from a modern lake shore in Anatolia, and 4 subfossil Unio shells from Çatalhöyük (dated between 7200 BC and 5000 BC, Neolithic and Chalcolithic periods). Sequential carbon and oxygen isotope analysis along the surface of the shells provides information on seasonal or shorter-term variability of lake waters during the lifetime of the organisms. δ¹⁸O values of the modern shell are consistent with it being collected from a dammed portion of the Seyhan River that does not undergo intensive summer evaporation. This is in contrast to many of the surface water bodies in Anatolia which suffer extensive evaporation in the arid summers. δ¹⁸O values of the subfossil shells from the Çatalhöyük middens indicate that the bivalves came from lakes which evaporated extensively during the summer months but were replenished by high winter rainfall, suggesting that the subfossil shells lived in relatively small lakes or ponds. Stable isotope analysis along the growth of freshwater bivalves is one of the few methods for investigating seasonal water fluctuations in the past. These results may alter current interpretations on the environment of Çatalhöyük during the Neolithic, although more work is needed to confirm these initial findings.     

Palaeontology of the Cerros Bayos section,Roca Formation (Danian), La Pampa Province,Argentina

Palynofloras from an outlier of Tertiary sediments in the One Tree Hill area north of Adelaide are nonmarine and correlate with similar assemblages from Middle Eocene North Maslin Sands from Maslin Bay and Golden Grove. Although there are similarities with time-equivalent Lower Nothofagidites asperus Zone palynofloras in the Gippsland Basin, a number of species in the South Australian palynofloras do not extend below the Late Eocene in the Gippsland sequences. This indicates earlier appearances for these species in southcentral Australia. The sediments overlie a highly weathered bedrock palaeosurface, indicating that a phase of significant weathering occurred prior to the Middle Eocene. A number of selected taxa are illustrated and their distribution in the palynofloras is discussed. Two new species, Proteacidites mildenhallii and Proteacidites parrawirrensis, are described and one species, Rhoipites byfieldensis, is emended.     

The Changing Exploitation of Oysters (Ostrea edulis L. 1758) in Late Medieval and Early Modern England: A Case Study from Dudley Castle,West Midlands

ABSTRACT

Analysis of over 4000 complete left oyster valves from late medieval and post-medieval Dudley Castle reveals the changing role of this perishable luxury over a 700-year period. Throughout the occupation, it seems that oysters were used as ingredients rather than served raw in the shell. A greater reliance on oyster consumption is apparent in the later fourteenth century, perhaps reflecting a more diverse diet amongst the aristocracy in the wake of the Black Death. An increased preference for mussels and whelks is also attested in the Tudor and early modern periods, reflecting changing perceptions of these foods.

Overall, it is likely that natural beds were exploited throughout the time that oysters were being brought to Dudley Castle; however, the evidence demonstrates a shift from limited exploitation of natural inter-tidal sources in the eleventh century towards the dredging of sub-littoral beds in later periods, with some possible translocation of oyster stock. Changes in the shape, size and appearance of the oyster shells suggest the source locales from which the oysters derived changed through time. A notable shift occurred in the fourteenth century, which could reflect changes in supply brought about by altered tenancy at Dudley Castle and/or disruptions to trade brought about by the Black Death. Future biochemical analyses are recommended to provide greater clarity on the origin of those sources.     

Shelly fauna from the Cambrian (Miaolingian,Guzhangian) Shannon Formation and the SPICE event in the Amadeus Basin,Northern Territory

Smith, P.M., Brock, G.A. & Paterson J.R. 20 September 2019. Shelly fauna from the Cambrian (Miaolingian, Guzhangian) Shannon Formation and the SPICE event in the Amadeus Basin, Northern Territory. Alcheringa 44, 1–24. ISSN 0311-5518

A low-diversity assemblage of linguliformean brachiopods, hyoliths, molluscs, bradoriid arthropods and echinoderms (ten taxa in total) is documented from the upper Shannon Formation (Cambrian, Miaolingian, Guzhangian; Mindyallan) in the Ross River Syncline and Todd River Anticline area, NE Amadeus Basin, central Australia. Taxa described include: the linguliformean brachiopods Treptotreta jucunda Henderson & MacKinnon, 1981, Opisthotreta sp., Stittia? sp., an undetermined acrotretid and an undetermined linguloid; the molluscs Kobayashiella? heritagensis Webers, Pojeta & Yochelson, 1992 (a paragastropod), and Apoptopegma joyceae sp. nov. (a rostroconch); the bradoriid Mongolitubulus sp.; Hyolithida gen. et sp. indet.; and isolated echinoderm plates. All fauna (including previously documented trilobites) from the upper Shannon Formation disappear at the beginning of a ～5‰ positive shift in δ¹³C, identified as the Steptoean Positive Isotopic Carbon Excursion (SPICE). Despite previous links between SPICE and a global extinction, as well as the disappearance of all faunal elements in the uppermost Shannon Formation, certain taxa reported herein range through the event elsewhere in the world. The occurrence of Treptotreta jucunda and Kobayashiella? heritagensis in younger (Furongian) deposits indicates these species survived the SPICE extinction event. This study advocates for more systematic and comprehensive sampling through stratigraphic intervals where the SPICE event occurs, especially for range data of complete faunas (rather than individual taxonomic groups), to facilitate a more complete picture of diversity trends through this important phase.

P.M. Smith* [patrick.smith@austmus.gov.au], Palaeontology Department, Australian Museum Research Institute, Sydney, New South Wales, 2010, Australia; G.A. Brock [glenn.brock@mq.edu.au], Department of Biological Sciences, Macquarie University, Sydney, New South Wales, 2109, Australia. J.R. Paterson [jpater20@une.edu.au], Palaeoscience Research Centre, School of Environmental and Rural Science, University of New England, Armidale, New South Wales, 2351, Australia. *Also affiliated with: Department of Biological Sciences, Macquarie University, Sydney, New South Wales, 2109, Australia.