Subjects -> PALEONTOLOGY (Total: 46 journals)
Showing 1 - 21 of 21 Journals sorted alphabetically
Acta Palaeontologica Polonica     Open Access   (Followers: 6)
Alcheringa: An Australasian Journal of Palaeontology     Hybrid Journal   (Followers: 7)
Ameghiniana     Open Access   (Followers: 1)
Annales de Paléontologie     Full-text available via subscription   (Followers: 7)
Annals of Carnegie Museum     Full-text available via subscription   (Followers: 1)
Boreas: An International Journal of Quaternary Research     Hybrid Journal   (Followers: 12)
Comptes Rendus Palevol     Full-text available via subscription  
European Journal of Protistology     Hybrid Journal   (Followers: 6)
EvoDevo     Open Access   (Followers: 4)
Facies     Hybrid Journal   (Followers: 10)
Fossil Record     Open Access   (Followers: 5)
Geobios     Full-text available via subscription   (Followers: 6)
Historical Biology: An International Journal of Paleobiology     Hybrid Journal   (Followers: 9)
Ichnos: An International Journal for Plant and Animal Traces     Hybrid Journal  
International Journal of Speleology     Open Access   (Followers: 3)
Journal of Paleolimnology     Hybrid Journal   (Followers: 6)
Journal of Paleontology     Hybrid Journal   (Followers: 11)
Journal of Quaternary Science     Hybrid Journal   (Followers: 31)
Journal of Vertebrate Paleontology     Full-text available via subscription   (Followers: 12)
Marine Micropaleontology     Hybrid Journal   (Followers: 2)
Micropaleontology     Full-text available via subscription  
Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen     Full-text available via subscription   (Followers: 4)
Novitates Paleoentomologicae     Open Access   (Followers: 1)
Open Quaternary     Open Access   (Followers: 1)
Palaeogeography, Palaeoclimatology, Palaeoecology     Hybrid Journal   (Followers: 13)
Palaeontology     Hybrid Journal   (Followers: 18)
Palaeoworld     Hybrid Journal   (Followers: 3)
PALAIOS     Hybrid Journal   (Followers: 7)
Paläontologische Zeitschrift     Hybrid Journal   (Followers: 4)
Paleobiology     Full-text available via subscription   (Followers: 6)
PaleoBios     Open Access   (Followers: 1)
Paleoceanography     Full-text available via subscription   (Followers: 4)
Paleontological Journal     Full-text available via subscription   (Followers: 5)
Paleontological Research     Full-text available via subscription   (Followers: 3)
Palynology     Hybrid Journal   (Followers: 2)
Papers in Palaeontology     Hybrid Journal   (Followers: 1)
Quaternaire     Open Access   (Followers: 2)
Quaternary Research     Full-text available via subscription   (Followers: 20)
Quaternary Science Reviews     Hybrid Journal   (Followers: 25)
Review of Palaeobotany and Palynology     Hybrid Journal   (Followers: 2)
Revue de Micropaleontologie     Full-text available via subscription  
Rivista Italiana di Paleontologia e Stratigrafia (Research In Paleontology and Stratigraphy)     Open Access   (Followers: 2)
Spanish Journal of Palaeontology     Open Access  
Swiss Journal of Palaeontology     Hybrid Journal   (Followers: 4)
Vertebrate Anatomy Morphology Palaeontology     Open Access   (Followers: 2)
Zitteliana     Open Access   (Followers: 5)
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Palaeoworld
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  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 1871-174X
Published by Elsevier Homepage  [3203 journals]
  • A latest Ordovician Hirnantia brachiopod fauna from western Yunnan,
           Southwest China and its paleobiogeographic significance
    • Abstract: Publication date: Available online 27 March 2019Source: PalaeoworldAuthor(s): Bing Huang, Hang-Hang Zhou, David A.T. Harper, Ren-Bin Zhan, Xiao-Le Zhang, Di Chen, Jia-Yu RongAbstractA new, high-diversity, latest Ordovician brachiopod fauna of nearly 800 brachiopod specimens was collected from the Wanyaoshu Formation (Hirnantian) in the Shaodihe section, Mangshi City, western Yunnan, Southwest China. Altogether 22 genera and two undetermined taxa were identified; dominant are Aegiromena, Anisopleurella, Fardenia, Dalmanella, Hirnantia and Hindella, less common, Paromalomena, Leptaena, Eostropheodonta, Cliftonia, Kinnella, Templeella and Plectothyrella, together with some rare Petrocrania, Xenocrania, Pseudopholidops, Palaeoleptostrophia, Skenidioides, Giraldibella, Draborthis, Dolerorthis and Toxorthis. This is one of the most diverse typical Hirnantia faunas, associated with the Kosov Province. The paleobiogeographic relationships between western Yunnan (Southwest China), Myanmar, Yichang (Central China), Tibet (Southwest China) and Kazakhstan are clarified using Network Analysis and NMDS. The fauna studied is most similar to that of Myanmar; both resided on the Sibumasu terrane. However, the recalculated network diagram, when including the data of Hirnantia fauna from the Prague Basin, indicates that the latter is more closely linked to that of western Yunnan, a testament to the very weak brachiopod provincialism during the Hirnantian, mainly due to the influence of dominant cosmopolitan taxa. Some species of the fauna display significant population variation. Two of the dominant taxa, Aegiromena and Anisopleurella are systematically described, whereas the other two common taxa, Fardenia and Hirnantia are measured and their outlines and internal structures analyzed.
       
  • Filling the gap between the Cambrian Explosion and the GOBE —
           Proceedings of the IGCP 653 Annual Meeting 2017 in Yichang, China
    • Abstract: Publication date: March–June 2019Source: Palaeoworld, Volume 28, Issues 1–2Author(s): Yuan-Dong Zhang, Thomas Servais, David A.T. Harper
       
  • Additional thylacocephalans (Arthropoda) from the Lower Triassic (upper
           Olenekian) Osawa Formation of the South Kitakami Belt, Northeast Japan
    • Abstract: Publication date: Available online 20 March 2019Source: PalaeoworldAuthor(s): Masayuki Ehiro, Osamu Sasaki, Harumasa Kano, Toshiro NagaseAbstractThe Lower Triassic Osawa Formation in the South Kitakami Belt, Northeast Japan, consisting mostly of mudstone of shallow-marine environment, was deposited during the late Olenekian (ca. 250 Ma), and is an important unit through which to examine the biotic recovery process after the end-Permian mass extinction. The Osawa Formation is the only unit in Japan that yields thylacocephalans (Arthropoda). Three species belonging to three genera have been reported before: Ankitokazocaris bandoi, Kitakamicaris utatsuensis and Ostenocaris sp. In addition to the known species, some thylacocephalans, including one new genus and three new species, are described in the present paper: Ankitokazocaris tatensis n. sp., Concavicaris parva n. sp., Miyagicaris costata n. gen. n. sp. and Ostenocaris' sp. Although Thylacocephala have a rather long stratigraphic range (from Silurian to Cretaceous) and are known from a wide geographical region, there are only about thirty genera in this group. The Osawa thylacocephalan fauna comprises at least five genera, making it one of the most diverse in the world at the generic level. During the Triassic Period, the Thylacocephala diversified and spread widely throughout low-latitude regions.
       
  • Nonmarine ostracodes at the Permian-Triassic boundary of the central part
           of the East European Platform
    • Abstract: Publication date: Available online 7 March 2019Source: PalaeoworldAuthor(s): Maria A. Naumcheva, Valeriy K. GolubevAbstractExtensive geological and paleontological materials from the upper Permian and the Lower Triassic of the East European Platform had been accumulated by the end of the 20th century. Recently obtained new data indicate the stratigraphic continuity of the East European Permian–Triassic succession. The Permian–Triassic boundary is in many sections associated with the boundary between the Zhukovian and Vokhmian regional stages. New stratigraphic data have led to the revision of the temporal distribution of Zhukovian and Vokhmian ostracodes. In contrast to previous ideas, the rapid development of genus Gerdalia already began in the Zhukovian time rather than in the Vokhmian. At the same time, the first Darwinula of the Triassic type also appeared in the Zhukovian. A proportion of the Permian species were found to cross the boundary between Zhukovian and Vokhmian. The degree of similarity between the Permian and Triassic ostracode assemblages turns out to be much higher than previously recognized.
       
  • An evaluation of biostratigraphic markers across multiple geological
           sections in the search for the GSSP of the base of the Serpukhovian Stage
           (Mississippian)
    • Abstract: Publication date: Available online 12 February 2019Source: PalaeoworldAuthor(s): Svetlana V. Nikolaeva, Alexander S. Alekseev, Elena I. Kulagina, Yury A. Gatovsky, Galina Yu. Ponomareva, Nilyufer B. GibshmanAbstractThis paper aims to evaluate potential biostratigraphic markers for the Viséan–Serpukhovian boundary in sections of Europe and Asia, to help identify the base of the global Serpukhovian Stage, which is a high priority task for Carboniferous biostratigraphy. Sections in the Serpukhovian stratotype area in the Moscow Basin contain a gap at the base of the Tarusian Regional Substage (basal in the classical Serpukhovian), so the traditional boundary defined in these sections cannot be precisely correlated with other successions worldwide. The IUGS Task Group to establish a GSSP close to the traditional Viséan–Serpukhovian boundary focused on the search for a new boundary marker, primarily on the first appearance datum (FAD) of the conodont Lochriea ziegleri in the lineage Lochriea nodosa to Lochriea ziegleri, considering it to be a suitable biostratigraphic event. The FOD (first occurrence datum) of L. ziegleri has been recognized in many successions worldwide, although only in a few sections the supposed evolutionary lineage of L. ziegleri was inferred. There are serious impediments to the FAD of L. ziegleri being universally accepted as the boundary marker. This paper presents a review of the FOD levels of L. ziegleri documented so far from multiple sections along with other correlatable markers (foraminifers and ammonoids) that can serve as additional points of reference in sections where a conodont record is poor or absent. The reviewed sections are Naqing Section (South China), Verkhnyaya Kardailovka and Kugarchi sections (South Urals, Russia), Mariinsky Log and Ladeinaya Mountain Sections (western slope of the Middle Urals, Russia), Novogurovsky Section (Moscow Basin, Russia), Vegas de Sotres Section (Cantabrian Mountains, Spain), Lugasnaghta Section (County Leitrim, Ireland), Wenne River Bank Section (Germany), and Milivojevića Kamenjar Section (Družetić, NW Serbia). We also included a compilation of data from sections of North England and southern Scotland. In this paper, we will mainly focus on newly described sections, while the discussion of most previously described sections was summarized by Nikolaeva et al. (2001, 2002, 2005, 2009b) and other publications, so they are only briefly mentioned in this review. It should be added that there is no such a thing as a perfect GSSP section, as each section has certain disadvantages, either lithological, paleontological, or both, so it is important to hear and discuss all the different opinions to develop the optimum strategy for future research. In addition, we analyze published records from several sites in North England and southern Scotland. We discuss the first appearances of the ammonoid genera Cravenoceras, Edmooroceras, Lyrogoniatites, Dombarites, and Platygoniatites, the foraminifers Neoarchaediscus postrugosus, Hemidiscopsis muradymica, H. hemisphaerica, species of Janischewskina and Monotaxinoides, Eostaffella pseudostruvei group, Eostaffellina decurta, and Endothyranopsis plana. We publish here for the first time the useful accounts of foraminifers and conodonts from the Mariinsky Log Section and Ladeinaya Mountain Section (Middle Urals, Russia), and re-figure several important type specimens from Europe and the Urals.
       
  • The Furongian (late Cambrian) Biodiversity Gap: Real or apparent'
    • Abstract: Publication date: Available online 12 February 2019Source: PalaeoworldAuthor(s): David A.T. Harper, Timothy P. Topper, Borja Cascales-Miñana, Thomas Servais, Yuan-Dong Zhang, Per AhlbergAbstractTwo major, extended diversifications punctuated the evolution of marine life during the Early Palaeozoic. The interregnum, however, between the Cambrian Explosion and the Great Ordovician Biodiversification Event, is exemplified by the Furongian Gap when there was a marked drop in biodiversity. It is unclear whether the gap is apparent, due to sampling failure or lack of rock, or real — associated with unique and fluctuating environments, a distinctive palaeogeography and extreme climates during the late Cambrian. Indications suggest that there has been little attention paid to this interval compared with those below and above, while some of the classical areas for Cambrian research, such as Bohemia, have poor coverage through the Furongian. Moreover, based on information available in databases and the literature, together with the ghost ranges of many higher taxa through the Furongian, data suggest that biodiversity in this stage has been significantly underestimated. Emphasis, to date, has been placed on widespread, deeper-water dark shale facies of the interval, with generally low diversity faunas, whereas shallow-water communities have often been neglected.
       
  • Agglutinated tubes as a feature of Early Ordovician ecosystems
    • Abstract: Publication date: Available online 12 February 2019Source: PalaeoworldAuthor(s): Lucy A. Muir, Joseph P. Botting, Bertrand Lefebvre, Christopher Upton, Yuan-Dong ZhangAbstractAgglutinated tubes are produced by a variety of marine organisms. Such tubes will readily break down after the death of the producer, and hence are likely to be found only in deposits with rapid burial and/or exceptional preservation. Here we document agglutinated tubes from four localities of Early Ordovician age. The Lower Ordovician (upper Tremadocian) Afon Gam Biota of North Wales, UK, contains a diverse fossil assemblage including algae, worms, sponges, hyoliths, tergomyans, echinoderms, trilobites, and other arthropods. The biota also includes locally abundant agglutinated tubes composed largely of echinoderm fragments, in particular glyptocystitid (including Macrocystella) stem and brachiole ossicles. The tube producer appears to have preferentially selected echinoderms for use in tube building, with trilobites and tergomyans only rarely incorporated in the tubes. These tubes are named Echinokleptus anileis n. gen. n. sp. Similar tubes, although incorporating individual echinoderm ossicles rather than complete animals, occur in the Lower Ordovician (lower Floian) Tonggao Formation of South China. Possible additional agglutinated tubes are found in the Tremadocian–Floian Fezouata Shale of Morocco; these examples are composed of a range of bioclasts including echinoderm remains and hyolithids. Further possible tubes composed of mixed shelly material were observed in the Floian Landeyran Formation, Montagne Noire, France. The occurrence of morphologically similar agglutinated tubes on different continental blocks and at different palaeolatitudes indicates that the group responsible (inferred to be a polychaete annelid) was diversifying as part of the Great Ordovician Biodiversification Event, and similar interpretations should be considered for problematic bioclastic accumulations elsewhere.
       
  • Correlating the global Cambrian–Ordovician boundary: precise comparison
           of the Xiaoyangqiao section, Dayangcha, North China with the Green Point
           GSSP section, Newfoundland, Canada
    • Abstract: Publication date: Available online 12 February 2019Source: PalaeoworldAuthor(s): Xiao-Feng Wang, Svend Stouge, Jörg Maletz, Gabriella Bagnoli, Yu-Ping Qi, Elena G. Raevskaya, Chuan-Shang Wang, Chun-Bo YanAbstractThe Cambrian–Ordovician boundary interval exposed at the Xiaoyangqiao section, North China is presented. The distribution of stratigraphically important fossils in the Xiaoyangqiao section revealed several nearly coeval graptolite, conodont, trilobite, and acritarch bioevents in the uppermost Cambrian–lowermost Ordovician carbonate-siliciclastic sedimentary sequence. The precise correlation to the Green Point GSSP section, western Newfoundland, Canada allows for the identification of the corresponding GSSP level in the Xiaoyangqiao section. The combined data from the Xiaoyangqiao section and the Green Point GSSP section provide a series of events that all can be applied as proxies for identification of the Cambrian–Ordovician boundary horizon outside the GSSP. Based on this, the Xiaoyangqiao section, Dayangcha, is here strongly recommended as a candidate for an Auxiliary Boundary Stratigraphic Section and Point section (ASSP) for the base of the Ordovician System, because it provides one of the best and most complete Cambrian–Ordovician transitions in the world and because the first planktonic graptolites are from the Xiaoyangqiao section.
       
  • Flora of the Kazanian–Urzhumian boundary in the middle Permian of
           the Russian Platform
    • Abstract: Publication date: Available online 12 February 2019Source: PalaeoworldAuthor(s): Alexey V. GomankovAbstractRich fossil plant localities in the upper Guadalupian and the lowermost Lopingian of the Russian Platform are confined to several discrete “levels” or “horizons” divided by intervals that are almost devoid of plant remains. One such “horizon” is located at the boundary between the Upper Kazanian and the Urzhumian of the regional stratigraphic scale. Numerous localities of this level can be grouped into two geographical clusters, the northern one being confined to the Kama River Basin, and the southern one to the Orenburg Region and Southern Bashkortostan. Regarding the southern localities, three floras that are seemingly successive in time can be distinguished. Against a common background of articulates (Paracalamites and Equisetites), the lowermost flora is characterized by the dominance of leaves of Rufloria (Cordaitanthales) with very rare conifers. Conifers (Quadrocladus, Sashinia, Dvinostrobus) and leaves of Phylladoderma (Peltaspermales) are the most abundant elements of the middle assemblage, whereas Rufloria leaves are very seldom found together with the peltasperm Ginkgophyllum and the conifer-like Steirophyllum. The uppermost flora is dominated by Odontopteridium and Ustyugia, two closely related genera of peltasperms, whereas cordaitaleans are totally absent. Comparison with the northern localities, which can be linked to the type sections of the Upper Kazanian and the Urzhumian, enables the dating of these assemblages in terms of the regional stratigraphic scale. All three floras prove to be confined to the uppermost Kazanian, and only the youngest one could also occur in the lowermost Urzhumian. As the stratigraphic ranges of all observed plant taxa exceed the total stratigraphic interval under study, the sequence of the floras seems to be caused by ecological (most likely climatic) factors rather than the actual evolution of plants. In particular, the observed gradual elimination of cordaitaleans confirms the general view on the extinction of this group on the Russian Platform. The southwestern boundary of the occurrence of cordaitaleans on the Russian Platform stretched from the southwest to the northeast, approximately parallel to the palaeolatitudes reconstructed on the basis of palaeomagnetic data. During the Guadalupian it moved to the northeast, which is to the north considering the position of the North Pole of that time. Cordaitaleans were the main peat-forming plants in the Late Palaeozoic of northern Pangea (in the Kuznetsk, Tunguska and Pechora Basins). So their retreat to the north was most likely a consequence and a reflection of the warming and drying of the climate.
       
  • Middle Miocene Cephalotaxus (Taxaceae) from Yunnan, Southwest China, and
           its implications to taxonomy and evolution of the genus
    • Abstract: Publication date: Available online 12 February 2019Source: PalaeoworldAuthor(s): Jian-Wei Zhang, Ashalata D’Rozario, Xiao-Qing Liang, Zhe-Kun ZhouAbstractThe infrageneric taxonomy of the genus Cephalotaxus Siebold et Zuccarini ex Endlicher (Taxaceae) is controversial as morphological characters have been doubted to change coherently among species. Although the epidermal features are considered as important characters in the taxonomy of conifers, they have not been systematically studied in this genus. Neogene foliage shoots with well-preserved epidermal structure not only can provide systematic links to the extant species, but also have implications for the taxonomical definition of the extant species by their epidermal features. In this paper, the morphologies of leafy shoots combining epidermal structure of a Neogene Cephalotaxus, which was collected from the middle Miocene of Southwest China, and ten extant species (variants) were studied. Morphology as well as epidermal structures was compared among species (variants) in Cephalotaxus. Based on the comparisons, the taxonomical definition of extant species in genus Cephalotaxus are discussed. Our results indicate that leaf morphological characters in combination with the features of epidermal structure can distinguish species in genus Cephalotaxus. The fossil foliage shoots from the middle Miocene of Southwest China were assigned to a new species, C. maguanensis n. sp., which shows close affinities to the extant C. hainanensis. On the basis of leaf and epidermal information, we suggest there are seven extant species in Cephalotaxus. With global cooling and the uplift of the Qinghai-Tibet Plateau since the middle Miocene, the cooling climate induced the differentiation and southward expansions of C. maguanensis, and its extant offspring, C. hainanensis, is distributed to Hainan Island and the Indo-Chinese peninsula.
       
  • Stratigraphy of the Lungmachi black shales from the Huaying drill core in
           southwestern China and its palaeogeographic implications
    • Abstract: Publication date: Available online 11 January 2019Source: PalaeoworldAuthor(s): Zong-Yuan Sun, Jun-Xuan Fan, Lei Wu, Qing Chen, Zhong-Yang Chen, Chao LiAbstractCore samples from the Huaying well, Sichuan Province, have been analyzed for both graptolite biostratigraphy and carbon isotope chemostratigraphy. The result shows a stratigraphic sequence of Lituigraptus convolutus, Stimulograptus sedgwickii and Spirograptus guerichi biozones, and records a strong positive shift of δ13Corg at the base of the Stimulograptus sedgwickii Biozone, which coincides with those from Cornwallis Island (Arctic Canada), Arisaig (Nova Scotia, Canada), and the Barrandian area (Bohemia). Two outcrops were also studied in the Huaying region. The Yanwanggou section shows a continuous, but complicated, stratigraphical sequence, from the upper Katian to the lower–middle Rhuddanian, then a sedimentary hiatus of ∼3.26 Ma, and finally a continuous sequence from the upper Aeronian to the lower Telychian, whereas the Liziya section and the Huaying well exhibit significant hiatus, which lasted from Hirnantian to middle Rhuddanian or early Aeronian times. Therefore, the eastern boundary of the Central Sichuan Oldland during the Ordovician and Silurian transition can be precisely constrained to a narrow area between the Huaying well-Liziya section and the Yanwanggou section, which indicates that the Central Sichuan Oldland was much larger than previously considered. The present data also indicate the existing of a so far unidentified stage of the Kwangsian Orogeny, which resulted in the uplift of some portions of the Yangtze Platform region and the consequent delay of the transgression in those places. The multi-stage hiatus, spanning at least from the upper Katian to middle Aeronian in the study area, resulted from a combined effect of the Hirnantian glacio-eustatic sea-level fall and the regional tectonic activity of the Kwangsian Orogeny.
       
  • The Zitai Formation in South China: unique deeper-water marine red beds in
           terms of lithology, distribution and δ13Ccarb chemostratigraphy
    • Abstract: Publication date: Available online 3 January 2019Source: PalaeoworldAuthor(s): Xiao-Cong Luan, Rong-Chang Wu, Ren-Bin Zhan, Jian-Bo LiuAbstractDuring the EarlyöMiddle Ordovician characteristic red carbonate beds, i.e., the Zitai Formation and its coeval units, developed in the deeper-water marine setting of the Yangtze Platform, South China. The temporal and spatial distribution of these reddish limestones is discussed based on published data and our own observations and analyses. The red limestones formed along the margin of the Yangtze Platform on a carbonate ramp during six stages. The different stages, (0) early Fl3 and before, (1) middle to late Fl3, (2) early Dp1, (3) middle to late Dp1, (4) Dp2, and (5) Dp3 to early Dw1, are associated with regional sea-level changes and tectonic movements. Several positive shifts in the δ13Ccarb record occur in the succession beneath the red beds. Their formation presumably was induced by a global transgression in association with the drowning of the Yangtze Platform. Better ventilation and oxygenation of sediments on the platform are also indicated by the marine red beds and together intensified the Great Ordovician Biodiversification Event. Other factors such as iron presumably play a significant role in controlling occurrences and distribution of the red limestone beds.
       
  • Unusual compound zooecia in the trepostome bryozoan Eostenopora from the
           Devonian of Guizhou, China
    • Abstract: Publication date: Available online 27 December 2018Source: PalaeoworldAuthor(s): Jun-Ye Ma, Paul D. Taylor, Caroline J. ButtlerAbstractEnlarged, ‘compound zooecia’ are described for the first time in a trepostome bryozoan. Several of these zooecia are visible in tangential sections of Eostenopora guizhouensis (Hu) from the Devonian (Eifelian) Houershan Formation of Houershan, Dushan, southern Guizhou, China. They are broad and occupy the space of two or occasionally three or four normal autozooecia. Some have bridging walls extending partway across the enlarged zooecial chamber. Without serial sectioning, the origin of compound zooecia in E. guizhouensis is debatable. However, the existence of irregular gaps in some zooecial walls leads to the hypothesis that compound zooecia originated from the loss by resorption of the skeletal walls between two normal autozooecia. The bridging walls are interpreted as a response by the bryozoan to restore the integrity of the constituent zooecia. By analogy with the ‘Doppelgänger’ zooids of some modern cheilostome bryozoans, compound zooecia of E. guizhouensis may have housed the lophophores of more than one zooid.
       
  • First record of marine gastropods (wentletraps) from mid-Cretaceous
           Burmese amber
    • Abstract: Publication date: Available online 26 December 2018Source: PalaeoworldAuthor(s): Ting-Ting Yu, Bo Wang, Ed JarzembowskiAbstractsGastropod fossils are rarely preserved in amber with only a few records of terrestrial snails. Two new species, Epitonium (Epitonium) zhuoi n. sp. and Epitonium (Papyriscala) lyui n. sp. are described based on two well-preserved specimens from mid-Cretaceous amber from northern Myanmar. Highresolution three-dimensional images using X-ray micro-computed tomography (micro-CT) are provided. These species can be attributed to the family Epitoniidae (wentletraps) based on the shell characters such as the slender and conical shell-shape, numerous whorls, round aperture and regular, axial sculpture of high, sharply-ribbed costae. Our find is the first record of marine gastropods preserved in amber, and suggests that the Burmese amber forest probably existed close to the seashore.
       
  • Ordovician trilobites from the lower part of the Dawan Formation
           (Floian–Dapingian) at Huanghuachang, Yichang, Hubei, southern China
    • Abstract: Publication date: Available online 26 December 2018Source: PalaeoworldAuthor(s): Zhi-Qiang Zhou, Zhi-Yi ZhouAbstractTwelve trilobite species assigned to 11 genera are described from the Lower Unit of the Dawan Formation at the Huanghuachang section of Yichang, Hubei, southern China, which has been ratified by the International Union of Geological Sciences (IUGS) as the Global Stratotype Section and Point (GSSP) for the base of the Middle Ordovician Series and the Third Stage (Dapingian) of the Ordovician System. Of these trilobites, five species, i.e., Carolinites genacinaca genacinaca, Ovalocephalus eoprimitivus, Rhombampyx chinensis, Taihungshania tachengssuensis, and Niobe (Niobella) obscura n. sp., occur in the lowermost part of the Dawan Formation, and are restricted to the upper part of the Oepikodus communis conodont biozone to the lower part of the Oepikodus evae Biozone. Two species, Liomegalaspides taningensis and Pseudocalymene transversa, are distributed almost throughout the Lower Unit of the Dawan Formation; two taxa, Annamitella sp. and Mioptychopyge sp., are recorded from the middle part and upper part of the Oepikodus evae Biozone, respectively; and two other species, Rhombampyx yii and Aulacopleura (Paraaulacopleura) dawanensis, appear in the upper part of the Lower Unit of the Dawan Formation, which is referred to the Middle Ordovician Microzarkodina flabellum-Baltoniodus triangularis Biozone. Agerina parva has a shorter range, across the Lower–Middle Ordovician boundary. The fauna is dominated by Liomegalaspides taningensis, which is assigned to the Liomegalaspides Biofacies, and indicates an inner-shelf environment.For regional chronostratigraphic correlation, the occurrence of the middle–late Floian (approximately Corymbograptus deflexus Zone) forms Carolinites genacinaca genacinaca and Taihungshania tachengssuensis in the fauna is of great significance: the former, a pelagic trilobite species, occurs extensively in North America, East Siberia, Novaya Zemlya, and Spitsbergen; the latter is widely distributed in the Yangtze Region, occurring in Sichuan, Guizhou, Yunnan, southern Shaanxi, and eastern Anhui as well as in Hubei.The trilobites of the fauna are mostly typical of the South China Plate and eastern Peri-Gondwana, but the presence of Agerina and Niobe (Niobella) suggests faunal links with coeval Baltoscandian assemblages, and the occurrence of Rhombampyx is indicative of a Laurentian affinity.
       
  • High resolution XCT scanning reveals complex morphology of gnathal
           elements in an Early Devonian arthrodire
    • Abstract: Publication date: Available online 19 December 2018Source: PalaeoworldAuthor(s): Yu-Zhi Hu, G.C. Young, Carole Burrow, You-an Zhu, Jing LuAbstractArthodire placoderms, as a possible sister group of Chinese ‘maxillate’ placoderms plus crown gnathostomes, provide important information regarding early evolution of jaws and teeth. High-resolution computed tomography and digital dissection on a unique articulated 400 million-year-old buchanosteid arthrodire permitsa detailed description of the three types of gnathal elements in basal arthrodires for the first time, giving insights into their morphology and the organization of the associated dentition. In displaying numerous denticle rows (dental fields), the gnathal element morphology is very different from the much-reduced denticulation of higher brachythoracid arthrodires, even though the latter have been used recently to interpret origin and early evolution of teeth. Ossification centres are anterolateral on the anterior supragnathal (attached to the braincase), anteromesial on the posterior supragnathal (attached to the palatoquadrate), and in the central part of the biting portion of the infragnathal (attached to the meckelian cartilage). The latter bone shows no evidence of two ossification centres as has been interpreted for more advanced arthrodires. Denticle rows radiating from the ossification centre form dental fields in all three elements, and are more similar to the gnathal elements of phlyctaeniid and actinolepid arthrodires than to advanced brachythoracids. The new evidence gives insights into the primitive arthrodire condition for comparison with the dermal jaw bones of Chinese ‘maxillate’ placoderms that have been homologised with the premaxilla, maxilla, and dentary of osteichthyans. The new details will help clarify the sequence of character acquisition in the evolution of marginal jaw bones in basal gnathostome groups.
       
  • Cambrian biostratigraphy of the Bowers back-arc basin, Northern Victoria
           Land, Antarctica — A review
    • Abstract: Publication date: Available online 17 December 2018Source: PalaeoworldAuthor(s): James B. Jago, Christopher J. Bentley, Roger A. CooperAbstractThe Bowers Mountains in Northern Victoria Land contain the richest Cambrian Series 3 (Miaolingian, middle Cambrian) and Cambrian Series 4 (Furongian, late Cambrian) fossiliferous successions in Antarctica. Almost all the fossils are found within the Bowers Supergroup, which outcrops within the Bowers Terrane, a fault-bounded northwest-southeast oriented strip in Northern Victoria Land. The fossils provide the main age control on the history and evolution of the Bowers volcanic arc and back-arc basin. The great bulk of the fossils occur within the Spurs Formation. The fossil assemblages are dominated by agnostoids and polymerid trilobites with most ranging in age from Drumian to Paibian, although one fauna is of Jiangshanian age. Over 40 agnostoid taxa and over 100 polymerid trilobite taxa have been recorded from the rocks of the Bowers Supergroup. The youngest fauna occurs within the adjacent Robertson Bay Terrane, where a limited fauna of polymerid trilobites and conodonts from within a limestone olistolith have a very late Cambrian or early Ordovician age. Faunal affinities are mainly with Australia, New Zealand, North and South China and the Himalaya with lesser ties to Iran, Kazakhstan, Siberia and Laurentia.
       
  • The bony labyrinth of Platecarpus (Squamata: Mosasauria) and aquatic
           adaptations in squamate reptiles
    • Abstract: Publication date: Available online 15 December 2018Source: PalaeoworldAuthor(s): Hongyu Yi, Mark NorellAbstractMosasaurs were among the last marine reptiles that lived before the Cretacesous–Paleogene extinction. Little is known about the sensory evolution of mosasaurs in relation to their aquatic lifestyle. In this study, the braincase of Platecarpus was CT-scanned and virtual models were constructed showing the bony labyrinth — or the inner ear — a sensory apparatus for balance and hearing. The virtual inner ear consists of the semicircular canals, vestibule, and cochlea. Compared with extant squamates, Platecarpus resembles sea snakes in having a small vestibule with a flat dorsal surface, but it differs from non-mosasaurian squamates in having rounded semicircular canals. Phylogenetic linear regression analysis supports a linear relationship, independent from phylogeny, between the length of the three semicircular canals and the length of the skull. The semicircular canals of Platecarpus are shorter than predicted, but the fossil data fell within the 95% prediction interval calculated from the extant data and the skull length of Platecarpus. Although size reduction of the bony labyrinth has been associated with aquatic adaptions in mammals, our results suggest that in squamates, semicircular canal size is related to skull size rather than habitat preference.
       
  • Amber fossils reveal the Early Cenozoic dipterocarp rainforest in central
           Tibet
    • Abstract: Publication date: December 2018Source: Palaeoworld, Volume 27, Issue 4Author(s): He Wang, Suryendu Dutta, Richard S. Kelly, Arka Rudra, Sha Li, Qing-Qing Zhang, Qian-Qi Zhang, Yi-Xiao Wu, Mei-Zhen Cao, Bo Wang, Jian-Guo Li, Hai-Chun ZhangAbstractThe palaeoenvironmental reconstruction of central Tibet is key to understanding the uplift history of the Tibetan Plateau, which had a profound influence on Cenozoic global climate and biotic change. Here we report an amber layer from the lower part of the Dingqing Formation (late Oligocene) in Lunpola of central Tibet, which is the first record of amber from Tibet. Herein we find that Lunpola amber is derived from dipterocarp trees, as determined by gas chromatography-mass spectrometry, which are restricted to and dominant in Asian rainforest nowadays. This amber forest represents the northernmost dipterocarp forest and is consistent with the hypothesis of out-of-India dispersal of Asian dipterocarps. The Lunpola amber most probably was derived from the lower part of the Niubao Formation (early–middle Eocene) and suggests a tropical/subtropical wet forest was present in central Tibet at least before the late Oligocene (probably early–middle Eocene).
       
  • Lower Cretaceous theropod tracks with the new ichnogenus and combination
           Lockleypus luanpingensis from the Dabeigou Formation of the Luanping
           Basin, Hebei Province, China
    • Abstract: Publication date: December 2018Source: Palaeoworld, Volume 27, Issue 4Author(s): Li-Da Xing, Hendrik Klein, Zuo-Huan Qin, W. Scott Persons, Xing XuAbstractTheropod footprints from the Jingshang tracksite in the Lower Cretaceous Dabeigou Formation of the Luanping Basin, Hebei Province, China, are re-evaluated after new discoveries at this locality. They occur in a succession with sandstone, mudstone, and calcareous shale. The depositional environment was a shallow lake shore, comparable in age to the famous Jehol Biota. Based on the distinct morphology with peculiar features of the ratio of the outer digits, the footprints formerly assigned to Changpeipus carbonicus are now referred to the new ichnogenus and combination Lockleypus luanpingensis. The possible trackmaker was a relatively large ornithomimosaurian theropod thus far not known from the skeletal record of the Jehol Biota.
       
  • Middle Jurassic Ginkgo leaves from the Daohugou area, Inner Mongolia,
           China and their implication for palaeo-CO2 reconstruction
    • Abstract: Publication date: December 2018Source: Palaeoworld, Volume 27, Issue 4Author(s): Chun-Lin Sun, Xiao Tan, David L. Dilcher, Hongshan Wang, Yu-Ling Na, Tao Li, Yun-Feng LiAbstractWell-preserved Ginkgo leaves with cuticle were collected from the Middle Jurassic Jiulongshan Formation in the Daohugou area, Inner Mongolia, China, which form the common elements in the Daohugou flora. Three new species of Ginkgo are recognized and their leaf morphology and cuticular structure are described for the first time. Two different pCO2 proxy models were applied to reconstruct palaeo-atmospheric CO2 concentration by using these new Ginkgo material. NLE (nearest living equivalent) suggests a semi-quantitative pCO2 estimate as 839 ± 99 ppmv with Carboniferous standardization and 419 ± 49 ppmv with Recent standardization. While Barclay’s revised SI-pCO2 regression suggests the estimates as 405 ± 71 ppmv. The results show that the pCO2 estimate is higher than today’s atmospheric CO2 concentration but lower than most of the other results on the Jurassic Period. Combined with the floristic composition, the climate at 165 Ma in the Daohugou area is inferred to be warm temperate.
       
  • Jurassic reef events in the Moroccan Atlas: A review
    • Abstract: Publication date: December 2018Source: Palaeoworld, Volume 27, Issue 4Author(s): Driss Sadki, Jin-Geng ShaAbstractIn the Moroccan Atlas, sedimentary deposits provide important data on reef events that characterize the Jurassic period. Recent work allows us to enhance knowledge of the Jurassic reefs in the Atlas, in particular their age, character and palaeogeographic distribution. Numerous localities with sponge-microbial mud mounds, coral reefs, and lithiotid bioherms are recorded from the Middle and High Atlas regions. These different biogenic constructions occupy different palaeogeographic settings: on the top of tilted blocks within the basin center; in slightly deeper positions, at the basin platform junction; and on adjacent platforms in the middle of the coastal area. The main episodes of reef building span nearly 30 million years, as follows: (1) Sinemurian, (2) early Pliensbachian, (3) late Toarcian, (4) Aalenian–early Bajocian (pars), and (5) late Bajocian. These five distinct reef events can be linked with general fluctuations of sea level and tectonism, and have palaeoclimatic implications.
       
  • Foraminifera, Radiolaria and Conodont assemblages from the Early
           Mississipian (late Tournaisian)/Early Pennsylvanian (early Bashkirian)
           blocks within the Mersin Mélange, southern Turkey: Biochronological and
           paleogeographical implications
    • Abstract: Publication date: December 2018Source: Palaeoworld, Volume 27, Issue 4Author(s): Cengiz Okuyucu, U. Kagan Tekin, Paula J. Noble, Yavuz Bedi, D. Gülnur Saydam-Demiray, Kaan SayitAbstractThe Mersin Mélange, a sedimentary complex in southern Turkey, includes blocks of various origins within a Late Cretaceous matrix. Two blocks in the Mersin Mélange are herein recognized to be of Carboniferous age. One block (the Kozan Block) is composed of alternating chert and mudstone, and includes radiolarian and conodont assemblages revealing a late Tournaisian (Early Mississippian) age. The other (Keven-West Block) consists of platform carbonate containing abundant foraminifera indicating Bashkirian (Early Pennsylvanian) age. These dates are so far the oldest obtained from the blocks within the Mersin Mélange. A correlation of the lithostratigraphies of blocks in the Mersin Mélange with the coeval Tauride sequences indicates that they correspond to the successions in the Beysehir-Hoyran Nappes. In these nappes, the late Tournaisian is characterized by radiolarian rich chert and mudstone of an open marine environment, whereas the Bashkirian succession represents a shallow water environment with Foraminifera-bearing limestone. The Tournaisian deepening can be ascribed to the opening of a deep marginal basin to the north of the Tauride Platform and uplifting of the northern Tauride-Anatolide Platform margin during the Late Mississippian and Early Pennsylvanian.A shallowing upward sequence started in the Tournaisian with a pelagic sequence followed by platform carbonates of Bashkirian age in the Beysehir-Hoyran Nappes, and could be related to a major glaciation event during late Visean–Serpukhovian resulting in a sea-level drop and deposition of platform carbonates in the Bashkirian. Given the stratigraphic properties of northerly originated nappe packages (Cataloturan, Hadim and Bolkardag) and parautochthonous/autochthonous sequences in Taurides, sedimentation on the Tauride-Anatolide Platform mainly terminated after the Moscovian, except in the Hadim Nappe with sedimentation in a very shallow sea conditions until the end of the Permian. A depositional break corresponding to the Kasimovian–Wordian time interval in these sequences in the Tauride-Anatolide Platform could be related to the effects of both late Paleozoic Gondwanan glaciation and a possible mantle plume occurrence evidenced by the geochemistry of lavas in the Mersin Mélange causing major uplift in the Northern NeoTehys Ocean. However; at the center of the plume, pelagic sequences (e.g., ribbon chert and pelagic limestone) were deposited associated with these lavas due to a progressive developing rift system during the Permian, based on previous studies.
       
  • Conodonts of the genus Lochriea near the Visean–Serpukhovian boundary
           (Mississippian) at the Naqing section, Guizhou Province, South China
    • Abstract: Publication date: December 2018Source: Palaeoworld, Volume 27, Issue 4Author(s): Yu-Ping Qi, Tamara I. Nemyrovska, Qiu-Lai Wang, Ke-Yi Hu, Xiang-Dong Wang, H. Richard LaneAbstractThe First Appearance Datum (FAD) of the conodont Lochriea ziegleri in the lineage Lochriea nodosa–L. ziegleri has been considered the most suitable definition and global correlation-level for a revised base of the Serpukhovian Stage. Abundant specimens of Lochriea are recorded throughout the Late Visean–early Serpukhovian interval in the Naqing section, South China. Among them, the P1 elements, with wide morphological variability, enable confirmation and refinement of main lineages within the genus. Two lineages are proposed: 1) noded Lochriea species, such as L. mononodosa–L. nodosa–L. ziegleri, L. senckenbergica and L. multinodosa, and 2) ridged Lochriea species such as L. monocostata–L. costata–L. cruciformis. The possibility for their phylogenetic relationships is evaluated in this paper.
       
  • Additional cricetid and dipodid rodent material from the Erden Obo
           section, Erlian Basin (Nei Mongol, China) and its biochronological
           implications
    • Abstract: Publication date: December 2018Source: Palaeoworld, Volume 27, Issue 4Author(s): Qian LiAbstractNew cricetid (Cricetops dormitor, Eocricetodon sp., Eucricetodon cf. E. wangae, Pappocricetodon schaubi) and dipodid (Allosminthus gobiensis n. sp., Allosminthus ernos, Allosminthus uniconjugatus, Allosminthus cf. A. majusculus, Primisminthus shanghenus, Sinosminthus sp.) occurrences from the “Lower Red”, “Middle Red”, “Middle White” and “Upper White” beds of the Erden Obo section in Nei Mongol, China are reported. They are first discovered in these horizons. On the basis of the comparison of the rodent assemblages, we consider that the age of the “Upper White” beds is early Oligocene, the age of the “Middle Red” and “Middle White” beds is probable more similar to the age of late Eocene Houldjin Formation and lower part of Chaijiachong Formation, and the age of the “Lower Red” beds is correlative to the Sharamurunian. The diversity of ctenodactyloid, dipodid, and cricetid appears to change, and the turnover in rodent fauna possibly responded to the environmental and climate change towards the end of middle Eocene.
       
  • Changhsingian (Late Permian) foraminifers from the topmost part of the
           Xiala Formation in the Tsochen area, central Lhasa Block, Tibet and their
           geological implications
    • Abstract: Publication date: Available online 10 November 2018Source: PalaeoworldAuthor(s): Feng Qiao, Hai-Peng Xu, Yi-Chun ZhangAbstractA foraminiferal fauna consisting of 15 genera and 19 species is documented for the first time from the topmost part of the Xiala Formation in the Aduogabu area in Tsochen County, central Lhasa Block. This foraminiferal fauna is dominated by Colaniella, indicating a broadly Changhsingian age. The presence of Colaniella, Reichelina and absence of the typical tropical fusuline genus Palaeofusulina in the fauna indicate that the Lhasa Block has not merged into equatorial regions during the Changhsingian. More importantly, the widespread Lopingian (Late Permian) marine carbonates with warm-water faunas and the stable platform carbonate sequence through the Guadalupian and Lopingian in the Lhasa Block present an obvious contrast against the contemporaneous sequences in the South Qiangtang Block and Gondwana margin. It suggests that both the Bangong-Nujiang Ocean and the Neotethys Ocean would have opened by the Guadalupian and Lopingian.
       
  • Diverse radial symmetry among the Cambrian Fortunian fossil embryos from
           northern Sichuan and southern Shaanxi Provinces, South China
    • Abstract: Publication date: Available online 10 November 2018Source: PalaeoworldAuthor(s): Xiao-Feng Xian, Hua-Qiao Zhang, Yun-Huan Liu, Ya-Nan ZhangAbstractThe Cambrian Fortunian fossil embryos exhibit embryonic development of ancient animals and hence have important bearings on evolutionary developmental biology. They have radial symmetry, and may be early representatives of cnidarians. Here we report new material of three-dimensionally phosphatized fossil embryos from the Fortunian Kuanchuanpu Formation and coeval strata in northern Sichuan and southern Shaanxi provinces, South China. The new material includes previously reported fossil embryos assignable to Pseudooides prima with biradial symmetry or pseudo-hexaradial symmetry, Quadrapyrgites quadratacris with tetraradial symmetry, and Olivooides multisulcatus with pentaradial symmetry. Additionally, we recovered two new types of fossil embryos, i.e., Embryo I with hexaradial symmetry and Embryo II with octaradial symmetry, and they are tentatively suggested to represent new cnidarians. In contrast to the diverse radial symmetry of the Fortunian cnidarians, modern cnidarians exhibit stable tetraradial symmetry in medusozoans, biradial symmetry in anthozoans, and bilateral symmetry in siphonophores (Hydrozoa). The current study supports the view that the tetraradial symmetry of modern medusozoans is a surviving remnant of their Fortunian relatives.
       
  • Mass-transfer based modeling to investigate iodine staining effects for
           enhanced contrast X-ray computed tomography
    • Abstract: Publication date: Available online 3 November 2018Source: PalaeoworldAuthor(s): Zhi-Heng Li, Fei Yan, Richard A. Ketcham, Matthew W. Colbert, Julia A. ClarkeAbstractIodine staining combined with X-ray computed tomography (CT) has become a core approach in anatomy, offering three-dimensional and essentially non-destructive imaging of soft tissues. Although there have been rapid advances in methodologies and techniques, the mechanisms underlying diffusible iodine contrast-enhanced CT are not yet fully understood. The protocols for staining samples of differing sizes and tissue types have not yet been justified theoretically. Here we utilize mass transfer modeling to simulate iodine diffusion and predict iodine concentrations within distinct tissue types. We also undertake iodine staining experiments to visualize the detailed anatomy and contrast effects on whole-body avian specimens using different concentrations of iodine solution to compare with model simulation results. The simulations effectively explain most observed concentration changes in differently-sized samples over distinct iodine treatment durations. These results also provide insight into the mechanisms behind the efficacy of solution replenishment for enhancing staining effects. Both consistencies and inconsistencies between our simulation and experimental results regarding iodine concentration in tissues will inform further investigations to optimize iodine staining protocols.
       
  • Palaeoenvironmental changes recorded in the palynology and palynofacies of
           a Late Permian Marker Mudstone (Galilee Basin, Australia)
    • Abstract: Publication date: Available online 3 November 2018Source: PalaeoworldAuthor(s): Alexander Wheeler, Nikola Van de Wetering, Joan S. Esterle, Annette E. GötzAbstractReconstructing the terrestrial palaeoenvironment during the end-Permian is made challenging by widespread erosion and ecosystem destruction. High-resolution sampling for palynofacies and palynology in sections that preserve the boundary interval allows for detailed examination of the drastic environmental changes that characterize the Permian–Triassic mass extinction. In the Bowen and Galilee basins in eastern Australia, this environmental perturbation is recorded within a Marker Mudstone that occurs above the uppermost Permian coal seams. The Marker Mudstone is used as a stratigraphic reference level at many localities, but has previously only been studied at a single locality in the Bowen Basin. In the present study, borehole Tambo 1-1A drilled in the Galilee Basin was selected to clarify whether this black, organic-rich mudstone marks a marine transgression, and to examine potential indicators of the end-Permian mass extinction. A total of 22 samples were taken from the mudstone unit, and from the over- and underlying strata and processed for palynology, palynofacies, and carbon isotope analysis.Biostratigraphic data indicate that the Marker Mudstone itself covers the uppermost part of unit APP5, with the first index taxa of unit APP6 floras occurring in samples less than 80 cm above this interval. This can be correlated with several other localities in the Bowen and Sydney basins where this shift occurs just above the uppermost Permian coal seam. Palynofacies data agree with previous interpretations of a southwards prograding delta that subsides as base level rises to form an extensive waterbody in which the Marker Mudstone was deposited. A change from translucent phytoclast-dominated to opaque phytoclast-dominated palynofacies within the Marker Mudstone suggests a shift to more oxic conditions in the water column, while base level begins to fluctuate, or increased terrestrial input from fluvial systems as the hinterland rises. Algal bodies resembling Botryococcus are found in the strata above the Marker Mudstone, but differ in morphology from the algal bodies found in the deltaic facies below. The presence of acanthomorph acritarchs in the Marker Mudstone and in the overlying Rewan Formation may indicate marine influence. Forms resembling fungal spores are present, but they do not show a “spike” as seen in other P–T boundary localities.The relative position of unit APP6 to the P–T boundary itself remains unclear. APP6 assemblages are dominated by simple acavate trilete and cavate trilete spores, which suggests stressed environment dominated by ferns and lycopods. The presence of degraded phytoclasts towards the top of the Marker Mudstone may also be used to suggest a mass-extinction interval. They may also be indicative of shifting local palaeoenvironmental changes, an interpretation that is supported by the low magnitude negative excursion of the δ13C isotope values within the Marker Mudstone. More datasets from the Bowen and Galilee basins will be essential to decoupling these signals.
       
  • New fish assemblages from the Middle Permian from the Guadalupe Mountains,
           West Texas, USA
    • Abstract: Publication date: Available online 26 October 2018Source: PalaeoworldAuthor(s): Alexander O. Ivanov, Merlynd K. Nestell, Galina P. Nestell, Gorden L. BellAbstractLate Wordian/Capitanian (Guadalupian, Middle Permian) fish assemblages are described from the “McKittrick Canyon Limestone”, Lamar Limestone and Reef Trail Members of the Bell Canyon Formation in the Patterson Hills and the PI section (Hegler/Pinery Members) along Highway 62/180 in the Guadalupe Mountains, West Texas. The assemblages contain chondrichthyan teeth of Stethacanthulus meccaensis, Texasodus varidentatus, Cooleyella cf. amazonensis, C. cf. peculiaris, and the new genus and species Lamarodus triangulus; and buccopharyngeal denticles of undetermined symmoriiform; chondrichthyan scales of eight morphotypes; fragment of an actinopterygian jaw, isolated teeth; the scales of Alilepis sp., Varialepis sp. and undetermined elonichthyid and haplolepid fishes. Using microtomography, the vascularization system has been observed for the first time for the teeth of Texasodus varidentatus and a new taxon Lamarodus triangulus. The distribution of chondrichthyan taxa was analyzed for the known fish assemblages of the Early, Middle, and Late Permian of the world. The end-Guadalupian crisis in the evolution of chondrichthyan fishes involved substantially more taxonomic change than the Permian–Triassic mass extinction.
       
  • Main biotic and climatic events in Early Permian of the Western Urals,
           Russia, as exemplified by the shallow-water biota of the early Kungurian
           lagoons
    • Abstract: Publication date: Available online 24 October 2018Source: PalaeoworldAuthor(s): Serge V. NaugolnykhAbstractThe paper deals with the Early Permian (mostly early Kungurian) biotas of the Cis-Urals (Perm region, Russia). Taxonomic composition of the early Kungurian biota of the stratotype area (close vicinity of the City of Kungur) includes algae Algites philippoviensis Naugolnykh, A. shurtanensis Naugolnykh, tracheophytes (higher plants), i.e., equisetophytes Paracalamites spp., conifers Shaidurodendron columnaris Naugolnykh, Walchia appressa Zalessky, vojnovskyaleans Rufloria derzavinii (Neuburg) S. Meyen etc.; invertebrates: coelenterates of uncertain affinity, bivalves Permophorus costatus (Brown), Permophorus sp., Netschajewia sp. cf. N. tschernyshowi (Licharew), gastropods Goniasma angulata (Stuckenberg), terebratulid brachiopods Dielasma sp. cf. D. moelleri Tschernyschew, arthropods (limulids Paleolimulus kunguricus Naugolnykh); vertebrates: chondrichthyan and actinistian fishes.Paleogeographically, the studied area belonged to the near-shore zone of a large lagoon basin disposed along the western-southern part of the Paleo-Urals during the Kungurian time. The main events in evolution of this basin reflect the final phases of the Artinskian sea basin with normal salinity, the transition to an early Kungurian (Philippovian) lagoon, then the appearance of intercalations of evaporate conditions and episodic incursion of marine faunas, and finally a gradual transition to semi-terrestrial environments with the cyanophyte communities in early Ufimian (Solikamskian, early Roadian) time. Climatic conditions in this area changed from semi-humid to semi-arid. A new genus and species of algae Dichothallus divaricatus Naugolnykh n. gen. n. sp. is described on the basis of material originated from the stratotype of the Philippovian Horizon of the Kungurian stage, Lower Permian.
       
  • Biostratigraphy and important biotic events in the Western Verkhoyansk
           Region around the Sakmarian–Artinskian boundary
    • Abstract: Publication date: Available online 13 October 2018Source: PalaeoworldAuthor(s): Ruslan V. Kutygin, Alexander S. Biakov, Victor I. Makoshin, Igor V. Budnikov, Leonid G. Peregoedov, Olga V. KrivenkoAbstractA diverse marine invertebrate fauna was found in the Echij Formation (Sakmarian–Artinskian) at the Arkachan, Chelge, and Nizhnyaya Dielendzha sections, all Western Verkhoyansk Region, North-East of Russia. The biostratigraphic sequence of ammonoid, brachiopod, bivalve, and foraminiferal assemblages in the Echij Formation of the Western Verkhoyansk Region is studied. Five ammonoids units are identified in the Echian Regional Stage (“Horizon”): Uraloceras subsimense, Uraloceras omolonense, Neoshumardites triceps hyperboreus, Eotumaroceras endybalense, and Eotumaroceras subyakutorum beds. The first two divisions contain ammonoids of the Arkachanian association, and the last three contain the Endybalian association. The boundary between the Sakmarian and Artinskian stages is established at the base of Neoshumardites triceps hyperboreus beds. In the Sakmarian interval of the Echij Regional Stage of the Verkhoyansk Region, a brachiopod biostratigraphic sequence similar to that of the Kolyma–Omolon Region is observed: Jakutoproductus insignis, Jakutoproductus terechovi, and Jakutoproductus rugosus zones. In the lower part of the Artinskian stage, Uraloproductus stuckenbergianus beds are identified, which are characterized by a rich brachiopod assemblage (Peregoedov et al., 2009), not typical for Verkhoyansk Region. The bivalves, identified in the Lower Echij Subformation, presumably belong to the Merismopteria permiana, Cypricardinia eopermica, and Cypricardinia borealica zones of the Ogonerian Horizon of the Kolyma–Omolon Region. Bivalves of the Middle and Upper subformations are characteristic of the Edmondia gigantea and Aphanaia lima zones of the Koargychanian Regional Stage (“Horizon”). The foraminifera complex identified in the Echij Formation is compared with the complex of the lower part of the Sandy Foraminifera horizon of the northeast of the Siberian platform, to which the Tustakh Formation belongs. The beginning of the wide distribution of the Early Permian foraminifera in the Western Verkhoyansk Region was recorded at the base of the Artinskian. The Sakmarian–Artinskian boundary interval in the Verkhoyansk Region is characterized by three significant biotic events: the replacement of the brachiopod Jakutoproductus by Inoceramus-like bivalves, the first appearance of the Endybalian ammonoid association, and biotic invasions from the Uralian and North American regions. An important factor of the Late Sakmarian–Early Artinskian events was a large sea level rise (the Echian transgression), which significantly changed the environmental conditions for East Siberian marine invertebrates, and contributed to the spread of new faunas.
       
  • A new conodont biozone classification of the Ordovician System in South
           China
    • Abstract: Publication date: Available online 8 September 2018Source: PalaeoworldAuthor(s): Zhi-Hao Wang, Yong Yi Zhen, Stig M. Bergström, Rong-Chang Wu, Yuan-Dong Zhang, Xuan MaAbstractA revised conodont biozonal scheme for the Ordovician of South China is presented herein based on extensive studies following the pioneer work by the late Professor An and his co-workers in the 1980s. This new classification of 33 biozones and subbiozones includes the conodont succession of the Yangtze Platform (29 biozones and subbiozones), the Jiangnan Slope (17 biozones), and a unique succession in the Qinling Orogen (four Katian biozones). The proposed biozone scheme provides more accurate correlations of the Ordovician strata in South China. As the best known and most detailed Ordovician conodont biozone succession in eastern Gondwana and peri-Gondwana, it will serve as a standard reference for correlation not only in this region but also for comparisons with the well-established biozone successions in Baltoscandia and North America. Furthermore, this new scheme has the potential to improve the precision in reconstruction of the conodont biofacies architecture in space and time. It will also assist in advancing our understanding of the timing and magnitude of biodiversification, oceanographic, and geological events at both the local and global scale.
       
  • Palaeogeographic distribution and diversity of cephalopods during the
           Cambrian–Ordovician transition
    • Abstract: Publication date: Available online 30 August 2018Source: PalaeoworldAuthor(s): Xiang Fang, Björn Kröger, Yuan-Dong Zhang, Yun-Bai Zhang, Ting-En ChenAbstractSince the early 20th Century, when the first cephalopods from late Cambrian strata were discovered in North China, more than 160 species belonging to 39 genera in nine families and five orders, have been described from both North and South China, together with North America, Siberia and Kazakhstan. We compiled and analysed all published Cambrian cephalopod occurrences in these regions: the results show that the oldest undisputed cephalopods are from the Jiangshanian Stage of North China. After their origination, cephalopods reached their first diversity peak in the late Cambrian Acaroceras–Sinoeremoceras Biozone (early Stage 10). This initial diversity peak was followed by the “late Trempealeauan Eclipse”, which eradicated nearly 95% of late Cambrian genera. The extinction event coincides with similar extinctions of trilobites and some other groups of marine life. The rapid subsequent diversification of cephalopods during the Tremadocian (Early Ordovician) was paralleled by a diversification of graptoloids and radiolarians.
       
  • Links between early Paleozoic oxygenation and the Great Ordovician
           Biodiversification Event (GOBE): A review
    • Abstract: Publication date: Available online 30 August 2018Source: PalaeoworldAuthor(s): Cole T. EdwardsAbstractThe Great Ordovician Biodiversification Event (GOBE) represents a four-fold increase of genus-level diversity that post-dates the diversification of the ‘Cambrian explosion’ by 40–50 Myr. A major increase in atmospheric oxygen (O2) levels is thought to be a leading cause of the ‘Cambrian explosion’ that lowered metabolic costs associated with skeletal and collagen biomineralization. The cause(s) of the GOBE, however, is (are) less well understood, and may include a cooling climate, increased nutrient availability, higher sea levels and increased ecospace, and further oxygenation of shallow marine environments. Atmospheric O2 levels are difficult to quantitatively estimate, particularly whether oxygenation was a plausible driver of the GOBE, because O2 estimates are hampered in part by the coarse time resolution of redox proxy records (e.g., iron-based geochemical data) and isotope mass balance models. Newly published high-resolution geochemical trends are used to better constrain the timing and degree of oxygenation across the GOBE, which include traditional methods such as stable carbon (δ13C) and sulfur (δ34S) isotope trends to estimate O2 levels on a global scale, and local-scale redox-sensitive proxies such as iodine (I/Ca) and trace metal concentrations and isotopes (e.g., Mo and U). Taken together, geochemical evidence suggests that Ordovician environments became progressively more oxygenated following the end of recurrent anoxic events and extinctions of late Cambrian and Early Ordovician marine faunas. A sluggishly circulating Cambrian global ocean could have maintained an oxycline in the water column that impinged upon the continental shelf, which extended into wide expanses of shallow shelf settings during relative sea level rises that caused positive δ13C and δ34S excursions and mass extinctions. Ordovician oxygenation roughly corresponds to cessation of positive δ13C excursions (i.e., shallow water anoxia) and the major pulses of biodiversification that comprise the GOBE, suggesting that oxygenation was an important driver of Ordovician biodiversity. Anoxic conditions below an oxycline that impinged upon the continental shelf likely persisted until the Devonian when a cooler climate invigorated circulation and ventilated the global ocean, with the possible exception of some isolated basins that were persistently anoxic.
       
  • Middle Triassic conodont apparatus architecture revealed by synchrotron
           X-ray microtomography
    • Abstract: Publication date: Available online 23 August 2018Source: PalaeoworldAuthor(s): Jin-Yuan Huang, Carlos Martínez-Pérez, Shi-Xue Hu, Philip C.J. Donoghue, Qi-Yue Zhang, Chang-Yong Zhou, Wen Wen, Michael J. Benton, Mao Luo, Hua-Zhou Yao, Ke-Xin ZhangAbstractThe composition of conodont apparatuses is crucial for understanding the feeding mechanisms of these early vertebrates. However, the multielement apparatus reconstructions of most species remain equivocal because they have been inferred from loose element collections, guided by knowledge from rare articulated ‘bedding plane assemblages’ and fused clusters, often from distantly related taxa. Even these natural assemblages can be difficult to interpret because the component elements can be closely juxtaposed or embedded in matrix, making it hard to discern the morphology of each element and their relative positions within the architecture of the feeding apparatus. Here we report five exceptionally preserved conodont clusters from the Middle Triassic Luoping Biota, Yunnan Province, Southwest China. These materials were scanned using synchrotron radiation X-ray tomographic microscopy (SRXTM), revealing the morphology and positional homology of the component elements in the fused clusters. We confirm that the apparatus of Nicoraella was composed of eight types of elements, comprising a total of 15 elements. SRXTM reveals the positional homologies of the component elements, viz. a single alate element is located in the S0 position, flanked successively abaxially by pairs of breviform digyrate S1 and S2 elements, bipennate S3 and S4 elements, and a pair of inwardly curved breviform digyrate M elements. Carminate elements occupy the P1 and P2 positions. The apparatus of Nicoraella is among the most completely characterised of all conodonts and serves as a template for the reconstruction of gondollellids.
       
  • Early Ordovician sponge-bearing microbialites from Peninsular Malaysia:
           The initial rise of metazoans in reefs
    • Abstract: Publication date: Available online 23 August 2018Source: PalaeoworldAuthor(s): Qi-Jian Li, Masatoshi Sone, Oliver Lehnert, Lin NaAbstractIntroductionEarly Ordovician (Floian) lithistid sponge-Calathium-microbial reefs were discovered in the lower part of the Lower Setul Limestone in Perlis, northwestern Malaysia Peninsula.ResultsWith a thickness of more than 30 m, massive microbial boundstone is surrounded by thick-bedded oncoid-intraclast rudstone/grainstone. The reefs were constructed of cylindrical stromatolites and maze-like thrombolites, accompanying a small proportion of lithistid sponges (anthaspidellids) and hypercalcified sponges (Calathium). The earliest Floian age is based on a conodont fauna including the zonal index species Serratognathus bilobatus.ConclusionsThe microbialites might have grown in shallow subtidal environments, indicated by the high aspect ratio of the stromatolites and the associated coarse-grained sediments. The initial growth of stromatolites was sufficient to inhibit hydrodynamic removal of sediment and to create microhabitats in which environmental conditions were favourable for later accretion of thrombolites and colonization by anthaspidellids and calathids. These sponge-bearing microbialites represent the initial rise of metazoans in reefs at the dawn of the Ordovician Radiation, providing crucial information for understanding the transition from microbial- to metazoan-dominant reefs during this unique interval.
       
  • Southwestern Gondwana’s Permian climate amelioration recorded in
           coal-bearing deposits of the Moatize sub-basin (Mozambique)
    • Abstract: Publication date: Available online 23 August 2018Source: PalaeoworldAuthor(s): Annette E. Götz, P. John Hancox, Andrew LloydAbstractThe postglacial climate history of Gondwana represents the most prominent climate amelioration in the Phanerozoic, ranging from severe icehouse conditions in the Late Carboniferous (Pennsylvanian) to extreme hothouse conditions in the Early Triassic. Here we report new sedimentological and palynological data from a 350 m thick coal-bearing succession intersected by borehole 945L_0022, drilled in the eastern Tete Province of Mozambique, which documents southwestern Gondwana’s Permian postglacial climate amelioration. Palynofacies data further support the environmental reconstructions interpreted from the sedimentary succession. Changes in the palynomorph assemblage document a shift from cold, to cool-temperate, to warm-temperate climatic conditions. This climate signature corresponds with observations from other depositional environments elsewhere in southern Africa, and thus enables correlation on a regional to interregional scale. Thick lacustrine deposits are described within the lower coal-bearing succession, reflecting the final glacial retreat, with melt waters supplying fresh water to the incipient lacustrine system. Lakes as characteristic postglacial sedimentary sinks are excellent palaeoclimate archives and the high Total Organic Carbon content of these fine-grained clastic sediments also makes them potential source rock targets for oil and gas.
       
  • New insights for ancient foraminifera through 3D visuals of fusulinids
    • Abstract: Publication date: Available online 1 August 2018Source: PalaeoworldAuthor(s): Yu-Kun Shi, Hao Huang, Zong-Hang ShenAbstractFusulinids are larger benthic foraminifera of late Paleozoic and index fossils for Permo-Carboniferous strata. The traditional methods to examine their internal structures are through ground thin sections, which however caused lots of ambiguities regarding the morphological diagnostics and taxonomic identification.In recent years, new technique of high resolution X-ray computed tomography sheds light on the microfossil examination and we had fusulinid individuals successfully processed with this innovative approach. Here we present the results of 19 Pseudofusulina specimens, including high resolution images and rendered three-dimensional (3D) visuals of the important internal structures, to unwrap more details of fusulinid morphology. This is the first time the full 3D visuals of fusulinid interiors were constructed and exhibited. Previous understandings on fusulinid basic morphology, such as proloculus, chamber development, are precisely described with 3D illustration; cuniculi and phrenotheca are discovered regularly among the specimens and therefore are not suggested to be diagnostic features of taxonomic splitting; test and proloculus morphology divergences caused by section orientation are captured. With assistance of high resolution CT technique, fusulinid morphology, especially internal structures, is much easier to acquire, understand, and exhibit, despite the critical limitation that only the fusulinid samples buried with terrigenous clasts, such as those from calcareous mudstone or argillaceous limestone, could be successfully scanned.
       
  • Tracing the evolutionary origins of the Hemichordata (Enteropneusta and
           Pterobranchia)
    • Abstract: Publication date: Available online 26 July 2018Source: PalaeoworldAuthor(s): Jörg MaletzAbstractThe early evolution of the Hemichordata (Enteropneusta and Pterobranchia) based on the available fossil record has its challenges and highlights. Even though the pterobranchs (Cephalodiscida and Graptolithina) secrete a highly durable housing construction or domicile (the tubarium), their fossil record is largely restricted to the tubaria of the planktic Graptoloidea, whereas the fossil record of their sister-group, the enteropneusts, is close to non-existent. Pterobranchs are present until today in a few inconspicuous taxa (Atubaria, Cephalodiscus, Rhabdopleura), but during the Ordovician Biodiversification Interval the planktic Graptoloidea was among the most highly evolved and diverse colonial organisms in the marine realm. The oldest definitive pterobranch fossils include Sokoloviina costata from the Rovno Horizon of Ukraine of possible basal Cambrian (Fortunian) age. Better preserved material originates from the Cambrian Series 2, Stage 4 and may be identified under the genus name Sphenoecium. Whereas Sphenoecium definitely represents a colonial pterobranch and can be referred to the Graptolithina, older material may be identified as ‘pterobranch’ only, as the fragmentary specimens cannot demonstrate coloniality unequivocally. These older ‘pterobranchs’ may alternately be referred to the non-colonial Cephalodiscida. According to the fossil record, the pterobranchs may have been the earliest group of animals to evolve coloniality during the Cambrian Explosion and, thus, differentiate between sexual and asexual reproduction in a single taxon. Coloniality also led to their evolutionary success in the early Palaeozoic.
       
  • Ordovician and Silurian ichnofossils from carbonate facies in Estonia: A
           collection-based review
    • Abstract: Publication date: Available online 17 July 2018Source: PalaeoworldAuthor(s): Ursula Toom, Olev Vinn, Olle HintsAbstractTrace fossils are common in the Ordovician and Silurian shallow marine carbonate succession of Estonia, with 45 ichnofossil genera and five bioclaustration structures identified, representing 31 categories of architectural designs and nine categories of ethological classification. Diverse soft sediment traces, bioerosional traces and bioclaustrations occur both in the Ordovician and Silurian. Diversity of trace fossils is similarly high in the Late Ordovician and Silurian, but markedly lower in the Middle Ordovician. This could be explained by the fact that during the Late Ordovician, Baltica drifted to the subtropical climatic zone where ichnofauna is usually more diverse than in temperate climatic settings. In addition, the Great Ordovician Biodiversification reached its peak in the Late Ordovician for many groups of organisms, which further contributed to the increase in ichnodiversity. Distribution of trace fossils is also controlled by the type of sedimentation, so that the mixed carbonate-siliciclastic systems prevailing in the Late Ordovician and Silurian have higher ichnodiversity than the pure carbonate settings of Middle Ordovician age. Feeding and locomotion traces are relatively rare in the Ordovician and Silurian of Estonia with the exception of the feeding structure Arachnostega, which is formed inside of protective shells and therefore has abundant occurrences. Bioerosional trace fossils may be extremely common in places, with a large number of different genera in the Upper Ordovician, supporting the idea of the Ordovician Bioerosion Revolution.
       
  • Integrated Lower–Middle Ordovician graptolite and chitinozoan
           biostratigraphy of the Jiangnan Slope Region, South China
    • Abstract: Publication date: Available online 26 June 2018Source: PalaeoworldAuthor(s): Wen-Hui Wang, Peng Tang, Wen-Jian Chen, Jing-Qiang TanAbstractAn integrated Early–Middle Ordovician graptolite and chitinozoan biostratigraphical study was carried out to improve the correlations between the two fossil groups in two sections in the Jiangnan Slope Region (deeper outer-shelf mud–sand–carbonate belt), South China. Six graptolite biozones and two chitinozoan biozones (including an undefined interval) were recognized. The chitinozoan Lagenochitina praepirum appears to be a stratigraphically useful species, despite being geographically restricted to South China, appearing at a level coincident with the first appearance of the index graptolite Levisograptus austrodentatus. Thus, the base of the Lagenochitina praepirum Biozone can also be regarded as the base of the Darriwilian Stage. The chitinozoan abundance in both sections is exceptionally low, and the assemblages do not contain the biostratigraphically important Belonechitina species. The distributions of both chitinozoans and graptolites are eco-dependent but show different onshore–offshore diversity trends. Chitinozoans are more diverse nearer to shore whereas graptolites are more diverse offshore, preferring slope facies. This may be caused by the different ecological preferences of chitinozoans and graptolites.
       
  • The onset of the Ordovician evolutionary radiation of benthic animals in
           the Baltic Region: Explosive diversity of attachment structures of stalked
           echinoderms, substrate revolution and the role of cyanobacterial
           communities
    • Abstract: Publication date: Available online 7 May 2018Source: PalaeoworldAuthor(s): Sergey RozhnovAbstractThe study of the Ordovician holdfasts of the Baltic Paleobasin revealed an explosive increase in the morphological diversity of echinoderms of the Baltic Paleobasin, up to 12 major morphological types in the Volkhov Regional Stage (Dapingian), reflecting an explosive growth in the taxonomic and morphological diversity of stalked echinoderms in general, but primarily crinoids. A sudden increase in the size and diversity of holdfasts at that time suggests a considerable increase in calcite production by stalked echinoderms and their adaptation to a wide distribution of a new type of substrate — hardgrounds and firm coarse-grained bioclastic substrates. The possibility of wide distribution of such substrates was due to a considerable increase, of at least an order of magnitude, in the carbonate productivity of benthic communities, whereas the rapid distribution of a new type of substrate and an explosive increase in the diversity and abundance of their inhabitants in the Baltic Basin was related to the appearance of positive feedbacks between the living and non-living components of this ecosystem. The existence of this positive feedback was due to cyanobacterial communities, the development of a biofilm on the substrate, and mineralization of an extracellular polymer substance, which led to the formation of hardgrounds and consolidation of the surface of the bioclastic substrates. The appearance in the Middle Ordovician of positive feedback between the expansion of the bioclastic substrates and an increase in carbonate production by their inhabitants, resulted in the Ordovician substrate revolution and explosive diversification of Ordovician benthic animals. Cyanobacterial films episodically appearing on the substrate, were an essential factor in the formation of this feedback.
       
  • Contrasting ecosystem impacts of biotic invasions in the Type Cincinnatian
           Series (Late Ordovician, Katian)
    • Abstract: Publication date: Available online 26 April 2018Source: PalaeoworldAuthor(s): Alycia L. Stigall, Ron FineAbstractSpecies migration events are common features of the fossil record, but the impacts of immigration events vary. In this paper, the pattern and impact of two types of immigration events are compared: ephemeral invasion and biotic immigration events (BIMEs). Specifically, this study focuses on biotic patterns preserved in Edenian, Maysvillian, and Richmondian (Late Ordovician, Katian) age strata in the Cincinnati, USA region. New Edenian occurrences of rhynchonelliformean brachiopod taxa belonging to the classic “Richmondian Fauna” are documented, and the ecological and evolutionary impacts of these short-lived pre-Richmondian invasions and the sustained Richmondian Invasion are compared. The Richmondian Invasion produced substantial ecological changes and evolutionary impacts within the Cincinnatian paleocommunity; however, the ephemeral invasions that occurred in the Kope Formation did not produce a marked or lasting impact on ecological relationships within Cincinnatian paleocommunities. In each instance, an Edenian novel immigration or biotic event was limited in temporal duration and did not exceed the time to deposit a single sedimentary package. Although such ephemeral invasions do not result in community-scale changes, they nevertheless provide important information about basin connectivity, provide insight into abiotic environmental conditions, and can be useful stratigraphic indicators.
       
  • Connecting the marine red beds with the onset of the Great Ordovician
           Biodiversification Event: A case study from the Laojianshan Formation of
           western Yunnan, Sibumasu Massif
    • Abstract: Publication date: Available online 25 April 2018Source: PalaeoworldAuthor(s): Xiao-Le Zhang, Yi Wang, Jian-Bo Liu, Jia-Yu Rong, Rongyu Li, Ren-Bin Zhan, Rong-Chang Wu, Peng TangAbstractDetails of the onset of the Great Ordovician Biodiversification Event (GOBE) remain unclear, and an emerging picture indicates that this process may have been linked to oceanic oxygenation. To address this question, we carried out a case study involving facies analysis and sea-level reconstruction on the Early to earliest-Middle Ordovician marine red beds (MRBs) of the Laojianshan Formation, western Yunnan, Sibumasu Massif. The Laojianshan Formation, formed prior to the main pulse of the GOBE, was deposited in four sedimentary belts including the basal lag, nearshore, inner shelf, and outer shelf. Sea-level curves reconstructed based on facies analysis are comparable to those of other major paleo-plates, indicating a eustatic control. The MRBs are widely distributed from the nearshore to the outer shelf belts, in which shelf deposition constitutes the major part. No explicit relationships between nearshore MRBs and sea level are found; however, shelf MRBs consistently coincided with transgressive intervals. The shelf MRBs generally indicate a very low organic carbon burial rate, which could be the result of a higher oxygen content in the ocean water and lower primary productivity. Comparative studies show that widespread shelf MRBs characterize the study interval while black shales were deposited in deeper settings, indicating widespread oxygenation in the pre-Darriwilian shelf, beyond which anoxia was largely restricted to the deeper ocean. Oxygenation may have ended the biomere-associated extinctions since the late Cambrian and promoted the onset of the GOBE.
       
  • Occurrence of the aglaspidid arthropod Beckwithia in the Furongian Guole
           Konservat-Lagerstätte of South China
    • Abstract: Publication date: Available online 17 April 2018Source: PalaeoworldAuthor(s): Xue-Jian Zhu, Rudy Lerosey-Aubril, Javier Ortega-HernándezAbstractThe Aglaspidida is a major group of Palaeozoic arthropods traditionally regarded as problematic, but whose evolutionary history has attracted renewed attention over the last decade. These efforts have resulted in an improved understanding of various aspects of aglaspidid palaeobiology, including their environmental, geographical and stratigraphical distribution, and phylogenetic relationships. Here, we describe a new weakly biomineralized non-trilobite arthropod from the Furongian Guole Konservat-Lagerstätte (Sandu Formation) in South China that contributes towards a more complete reconstruction of aglaspidid evolution and diversity during the late Cambrian. Beckwithia' gracilis n. sp. resembles the type species B. typa in the possession of a reentrant posterior cephalic margin, general trunk appearance and coarse tuberculation, but differs in having a more slender construction and a homogeneous exoskeletal sculpture. A revision of putative Beckwithia from Australia and Russia argues against their inclusion in this taxon, making the new species the only representative of the genus outside Laurentia. After Aglaspella and Glypharthrus, also from the Guole biota, this is the third aglaspidid genus shared between Laurentia and South China, which supports the hypothesis that some aglaspidids had great dispersal capabilities.
       
  • Dispersal and endemic diversification: Differences in non-lithistid
           spiculate sponge faunas between the Cambrian Explosion and the GOBE
    • Abstract: Publication date: Available online 29 March 2018Source: PalaeoworldAuthor(s): Joseph P. Botting, Lucy A. MuirAbstractNon-lithistid spiculate sponges were major components of Cambrian and Ordovician communities, but currently there is limited understanding of how sponge distribution patterns developed during the Cambrian Explosion and the Great Ordovician Biodiversification Event (GOBE). We compiled data on Cambrian and Ordovician sponge occurrences from the literature and our own research. Sponge genera were widely distributed during the Cambrian Period, with broadly consistent assemblages between palaeocontinents, from different palaeolatitudes, and over a timespan of approximately 25 Myr. Sponges exhibited a marked shift from cosmopolitan to highly endemic genera during the Tremadoc and later Ordovician. Surviving Cambrian genera continued to be very widespread, but taxa that originated during the Ordovician had much narrower geographic and environmental ranges, perhaps related to the origination of modern-style, patchy ecology. The cosmopolitanism of the Cambrian faunas is suggestive of rapid dispersal of recently evolved groups without competition from pre-existing sponges, suggesting that sponges had not diversified during the Precambrian. In contrast, the Ordovician record indicates local diversification against a complex ecological backdrop. Based on the ecological record of sponges, the Cambrian Explosion was a fundamentally different process to the GOBE.
       
 
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