Description: Publication date: 15 September 2018 Source: Palaeogeography, Palaeoclimatology, Palaeoecology, Volume 505 Author(s): Dan C. Jipa

Description: Publication date: 15 September 2018 Source: Palaeogeography, Palaeoclimatology, Palaeoecology, Volume 505 Author(s): Gildas Merceron, Marc Colyn, Denis Geraads Today, the family Giraffidae is restricted to two genera endemic to the African continent, Okapia and Giraffa , but, with over ten genera and dozens of species, it was far more diverse in the Old World during the late Miocene. We attempt to describe here how several species may have shared feeding resources in the Eastern Mediterranean. Dietary preferences were explored by means of Dental Microwear Textural Analysis in combination with estimation of body mass and the maximum height at which the various species were able to browse. One of our main results concerns the modern okapi, Okapia johnstoni . It is a forest dweller usually regarded as a browser, but we show that it might also forage on tough plants, possibly herbaceous monocots. Such feeding habits including portions of herbaceous monocotyledons were also found for some extinct species, especially the genera Samotherium and Palaeotragus . Palaeogiraffa shows a contrasted pattern: the specimens of P. pamiri from a site in Thrace were leaf-dominant browsers whereas those belonging to P. major and P. macedoniae from the Axios valley in Greece ingested herbaceous monocotyledons. Helladotherium duvernoyi , the only sivatheriine analyzed here is described as a leaf-dominant browser. The giraffine Bohlinia attica also falls within the leaf-dominant browser category but could browse on higher foliages than H. duvernoyi . On the whole, the reconstructed diets confirm the relationship between more grazing habits and smaller premolars, but not with higher dental crown height.

Description: Publication date: 15 September 2018 Source: Palaeogeography, Palaeoclimatology, Palaeoecology, Volume 505 Author(s): Tian Ying, David Shaw, Simon Schneider Sediments of the long-lived Lake Nanning in southern China (Guangxi Province) have yielded rich and diversified fossil biota of Oligocene age. The history of research on these fossils is documented herein, and revised lists of the flora and fauna recorded from Lake Nanning are provided. Based on newly collected data, the mollusc fauna and palynology of the lake sediments are assessed. Gastropods (Viviparidae, Stenothyridae), bivalves (Unionidae), ostracods and fish have successfully radiated in Lake Nanning, and developed a variety of endemic species. Shell thickening, spines, carinae, nodes and restricted apertures in bivalves and gastropods are interpreted as armour to prevent predation by giant shell crushing carp. Four different, successive macro-mollusc associations are documented, and can likely be used for relative dating of the lake sediments. Palynomorph assemblages from different lake stages are dominated by cool temperate conifer pollen and freshwater algae. The new findings suggest that the sediments of the Yongning Formation were deposited during or after Eocene–Oligocene cooling and are Oligocene in age. This also supports the biostratigraphy based on rare mammal finds. The fossils of Lake Nanning are outstandingly well preserved and provide a great opportunity to study endemic lake radiations. Besides, the lake sediments are one of the most important Oligocene climate archives of the region.

Description: Publication date: 15 September 2018 Source: Palaeogeography, Palaeoclimatology, Palaeoecology, Volume 505 Author(s): Elsbeth E. van Soelen, Wolfram M. Kürschner The Late Permian extinction interval is in many marine locations characterized by the development of anoxic conditions. The Finnmark Platform is one of few exceptions, as sedimentological and palynofacies evidence indicate oxygenated conditions throughout the event. Changes in acritarch assemblages and morphology were studied in order to better understand the link between acritarchs and environmental conditions. The main taxa are of Micrhystridium , Baltisphaeridium and leiospheres, while Veryhachium and the prasinophytes Cymatiosphaera and Tasmanites were present in low abundances. Increased concentrations of acritarchs, particularly Micrhystridium , show that the environmental changes at the start of the extinction event may have resulted in enhanced marine productivity. A shift from Micrhystridium/Baltisphaeridium dominance before and during the extinction event, to leiosphere-dominance after the extinction event, indicates a shift towards a more inshore environment. The new data are compared with published Late Permian acritarch records from East Greenland, China and Pakistan. A striking difference between the East Greenland and Finnmark Platform, which are both expanded Upper Permian/Lower Triassic sections, is that the acritarch record from Greenland shows a strong decrease in process length of the acritarch Micrhystridium . Together with a change in the acritarch assemblage, this change in morphology was interpreted to represent a decrease in salinity at the site, resulting from increased run-off. The differences between the East Greenland and the Finnmark records are likely due to their palaeogeographical settings, as the East Greenland section was located in a narrow and elongated basin which was likely more sensitive to evaporation and run-off changes than the Finnmark Platform.

Description: Publication date: 15 September 2018 Source: Palaeogeography, Palaeoclimatology, Palaeoecology, Volume 505 Author(s): Shan Chang, Sébastien Clausen, Lei Zhang, Qinglai Feng, Michael Steiner, David J. Bottjer, Yan Zhang, Min Shi Lower Cambrian assemblages of phosphatic and chitinous tubular fossils of probable cnidarian affinities were recovered from the Yanjiahe, Shuijingtuo and Shipai formations in the Three Gorges area, South China. Terreneuvian Cambrorhytium cf. C . major co-occur with an unnamed taxon in the Yanjiahe Formation. They can be compared with specimens from the Ediacaran Miaohe Fauna in the Three Gorges area. The most abundant and diversified cnidarian assemblages, including Cambrorhytium gracilis n. sp., Cambrorhytium cf. major , Cambrorhytium minor , Sphenothallus songlinensis , Sphenothallus taijiangensis ?, Sphenothallus kozaki , ? Sphenothallus sp., ? Byronia sp., and ? Mackenzia sp. are reported from the overlying, Cambrian Stage 3–4, Shuijingtuo and Shipai formations. These new fossils show previously unknown evidence for cnidarian affinities, such as an attachment disk, clonal clusters and probable budding structures. These diversified assemblages of probable cnidarian fossils further fill major gaps in the Cambrian record of stem metazoans and document associated early evolutionary patterns. In addition, our discovery suggests that along with sponges, these tubular fossils represent another important component of benthic ecosystems that colonized often dysoxic, deep-settings during the Cambrian explosion. The observed increases of average body-size and biomineralization among these probable cnidarians are tentatively linked to oxygenation of deep oceanic settings and appearance of predatory pressure during the Ediacaran–Cambrian transition, respectively.

Description: Publication date: 15 September 2018 Source: Palaeogeography, Palaeoclimatology, Palaeoecology, Volume 505 Author(s): Lu Sun, Chenglong Deng, Xiaoming Wang, Qian Li, Huafeng Qin, Huiru Xu, Yanfen Kong, Bailing Wu, Suzhen Liu, Rixiang Zhu Detailed understanding to the evolution of Neogene land mammals in East Asia and its intercontinental correlation has been impeded by the absence of an integrated biochronological system of this region. The numerous and diverse records of Neogene vertebrate fossils preserved in Inner Mongolia of northern China play a key role in the establishment of an independent biochronological framework in East Asia. However, most of these faunas are poorly constrained by independent chronological controls due to the scattered distribution of fossil localities and insufficient exposure of the fossiliferous strata. Additionally, age estimates by mammalian evolution and correlation often have uncertainties greater than ~1–2 million years. Here we present new magnetostratigraphic results of the Baogeda Ula Fauna, which was generally assigned an early Baodean Age (Late Miocene), or equivalent to the European MN12 zone (middle Turolian). Hipparion remains and associated vertebrate fossils were excavated from the upper part of the fluvio-lacustrine Baogeda Ula Formation near Abaga Banner, central Inner Mongolia of northern China. At least two layers of basalt sheet flows can be observed on top of the Baogeda Ula Formation. Our magnetostratigraphy, aided by published biochronology data and K–Ar ages of the lower basalt layer suggests that the Baogeda Ula Fauna consisting of three fossiliferous horizons can be placed within chron C4n.1n with an age range of 7.642–7.528 Ma. Thus, the Baogeda Ula Fauna becomes the first and only Baodean assemblage that is constrained by both magnetostratigraphy and radiometric ages, offering an anchoring point for future biochronological correlations.

Description: Publication date: 15 September 2018 Source: Palaeogeography, Palaeoclimatology, Palaeoecology, Volume 505 Author(s): Kaarel Mänd, Karlis Muehlenbachs, Ryan C. McKellar, Alexander P. Wolfe, Kurt O. Konhauser Ambers—fossilized plant resins—are a rich and unique source of paleoecological data due to their ability to preserve soft body fossils. However, interpretations concerning their environmental context are often hampered by uncertainties in the relationship between assemblages of inclusions and geological context, particularly in the case of secondarily redeposited ambers such as those from the Paleogene of Central Europe. Here we use stable carbon and hydrogen isotope analyses, as well as FTIR spectroscopy, from the northwestern Ukrainian Rovno amber deposit, to provide independent constraints on the geographic and temporal origins of Rovno amber. These analyses address the relationship between the Rovno and Baltic amber deposits as well as German Bitterfeld amber—a subject of considerable debate regarding their provenance. Rovno amber has a δ 13 C signature of −23.3 ± 0.9‰, similar to both Baltic and Bitterfeld ambers. Since there is a secular decreasing δ 13 C trend among amber deposits since the Early Eocene, a roughly contemporaneous origin of these deposits in the Eocene can be deduced. However, Rovno amber displays a δ 2 H signature of −258 ± 9‰, 19‰ more positive than Baltic amber, and directly comparable to Bitterfeld amber. This difference relates to precipitation sources and mean annual temperatures of the amber source regions, and suggests a much more southerly origin of Rovno amber relative to Baltic amber. FTIR spectra of each of these ambers are nearly identical and suggest that resin-producing trees were from similar families, despite contrasting source regions. Thus, we provide the first clear geochemical evidence for the distinct origin of Rovno and Baltic amber deposits, with implications for paleoecological studies involving inclusions from these deposits, and for determining the provenance of archaeological amber finds.

Description: Publication date: 15 September 2018 Source: Palaeogeography, Palaeoclimatology, Palaeoecology, Volume 505 Author(s): Xinying Zhou, Jilong Yang, Shiqi Wang, Guoqiao Xiao, Keliang Zhao, Yan Zheng, Hui Shen, Xiaoqiang Li We present new pollen data from a drilling core from the North China Plain which illustrate the nature of vegetation evolution in the temperate zone of Asia during an interval containing the Mid-Pleistocene Transition (MPT), ~1.2–0.7 Ma. Results show that, from 1.7–1.2 Ma, closed needle-leaved and broadleaved mixed forest predominated. The most important vegetation change event occurred at 1.2 Ma when there was a decline in coniferous forest and a significant increase in Artemisia , Chenopodiaceae and Poaceae grassland. There was a continued degradation of the regional forest vegetation and its replacement by woody grassland about 0.7 Ma. Patterns of vegetation change correlate closely with the key climate fluctuations of the MPT and coincide with major turnover events of large mammalian fauna (>10 kg) in China. In particular, >50% of large mammalian species became extinct in the course of the forest decline; however, they were replaced by new mammalian species after 0.7 Ma. Comparison of the vegetation and faunal records indicates that the process of forest replacement by grassland in the northern temperate zone during the MPT was associated with an acceleration of the rate of turnover of the large mammalian fauna, in terms of extinction and speciation.

Description: Publication date: 15 September 2018 Source: Palaeogeography, Palaeoclimatology, Palaeoecology, Volume 505 Author(s): Hugo Schmidt-Neto, Renata Guimarães Netto, Jorge Villegas-Martín We report the occurrence of sponge borings in composite molds of heteropectinid shells from Early Permian marine siliciclastic deposits of the Paraná Basin of southern Brazil. Sponge borings are preserved mainly as chambers ( Entobia ) and channels ( Entobia and Clionolithes ). Three preservational variations of Entobia are present, morphologically equivalent to the alpha, beta, and gamma ontogenetic stages of clionid sponges. This equivalence suggests that the ontogenetic behavior in clionid sponges remains the same since Early Permian times and points to a conservative evolutionary trend for this group. The pattern of bioerosion and other taphonomic signatures indicate rapid shell burial due to frequent and energetic storm events that might have limited the time available for bioerosion activity. The new findings improve the Paleozoic record of Entobia and Clionolithes and indicate that sponge borings have potential to be preserved in ancient siliciclastic rocks.

Description: Publication date: 15 September 2018 Source: Palaeogeography, Palaeoclimatology, Palaeoecology, Volume 505 Author(s): Karen J. Taylor, Seamus McGinley, Aaron P. Potito, Karen Molloy, David W. Beilman This study provides the first mid to late Holocene chironomid-inferred temperature (C-IT) model for northwest Ireland, creating a valuable climatic context for the development of Irish society during the Neolithic and Bronze Age. Using a lake sediment core from an isolated catchment, Lough Meenachrinna in northwest Ireland, a multi-proxy approach of chironomid (Diptera: Chironomidae) subfossils, sediment geochemistry (δ 13 C, δ 15 N, C:N) and pollen analysis was used to assess any potential limnological impact from prehistoric human activity in the region and provide a quantitative summer temperature estimate for the late Mesolithic to the Iron Age (7050–2050 cal yr BP). The pollen record provides a local signal of human activity, showing low levels of pastoral indicators in the early Neolithic, with increased evidence for pastoral and arable farming during the Bronze Age and in particular the Iron Age. Human activity does not appear to be a driving force in lake system change at Lough Meenachrinna, as peaks in farming indicators (e.g. pastoral pollen indicators and increased δ 15 N values) were not concurrent with major fluctuations in the chironomid assemblages. C-ITs provide evidence of multiple fluctuations in temperature during the mid to late Holocene with a cold phase during the late Mesolithic (6800–5890 cal yr BP), followed by a warming period during the early Neolithic (5890–5570 cal yr BP). C-ITs reflect a relatively warm climate during the middle Neolithic, with a substantial warming from the late Neolithic into the early Bronze Age (4630–3810 cal yr BP). C-ITs show a general cooling trend from the Bronze Age into the Iron Age, with a cold event occurring at 3340 cal yr BP during the middle Bronze Age and second cold event at 2430 cal yr BP during the Iron Age. The multi-proxy approach has proven an effective strategy for untangling human and climate influences on the chironomid record, and is recommended as a methodological approach in future Holocene climatic reconstructions where prehistoric human influence is a factor.