217 research outputs found
Early Cambrian Arthropods from the Emu Bay Shale Lagerstatte, South Australia
No full text© Instituto Geológico y Minero de España. The document attached has been archived with permission from the publisher.John R. Paterson, James B. Jago, James G. Gehling, Diego C. García-Bellido, Gregory D. Edgecombe and Michael S.Y. Le
Cambro-Ordovician studies VI
No full textTrilobites and sedimentary facies of the upper Coquena formation (late Tremadocian; 'Notopeltis orthometopa' Zone), Cordillera Oriental, Northwestern Argentina / M. Franco Tortello, Maria Benitez del Huerto, Susana B. Esteban -- An enigmatic univalve macromollusc from the lower Cambrian (Series 2, Stage 3) Heatherdale Shale, South Australia / Sarah M. Jacquet, James B. Jago, Glenn A. Brock -- Ordovician (Darriwilian-Sandbian) linguliform brachiopods from the Southern Cuyania Terrane of West-central Argentina / Lars E. Holmer, Leonid E. Popov, Oliver Lehnert, Mansoureh Ghobadi Pour -- Cambrian series 3 (Drumian) trilobites from limestone olistoliths, Reilly Ridge, Northern Victoria land, Antarctica / Christopher J. Bentley, James B. Jago, Roger A. Cooper -- Whitehouse's 'Redlichia' (Trilobita) specimens from the Georgina Basin, Western Queensland / John R. Laurie -- International correlation of the Cambrian series 2-3, stages 4-5 boundary interval / Frederick A. Sundberg, Gerd Geyer, Peter D. Kruse, Linda B. McCollum, Tatyana V. Pegel, Anna Zylinska, Andrey Yu. Zhuravlev -- Linguliformean brachiopods from the early Templetonian (Cambrian series 3, stage 5) Giles Creek Dolostone, Amadeus Basin, Northern Territory / Patrick M. Smith, Glenn A. Brock, John R. Paterson -- The mid-Cambrian (Drumian; Marjuman) trilobites 'Athabaskiella' Kobayashi 1942 and 'Bathyuriscidella' Rasetti 1948 (Dolichometopidae) from Quebec and Newfoundland, eastern Canada / Shelly J. Wernette, Stephen R. Westrop -- The present status of Tasmanian Cambrian biostratigraphy / James B. Jago, John R. Laurie, Keith D. Corbett, Christopher J. Bentley -- Geological context, biostratigraphy and systematic revision of late early Cambrian olenelloid trilobites from the Parker and Monkton formations, northwestern Vermont, U.S.A. / Ed, Landing, Mark Webster -- 'Ovatoryctocara granulata' assemblage (Cambrian series 2-series 3 boundary) of Londal, North Greenland / John S. Peel, Michael Streng, Gerd Geyer, Artem Kouchinsky, Christian B. Skovsted -- A new Ordovician paterinate brachiopod from the Barrandian area of the Czech Republic / Michal Mergl, Petr Kraft -- Ordovician trilobites from the uppermost Zhuozishan Formation (early Darriwilian) at Zhuozishan, Wuhai, Inner Mongolia / Zhou Zhiyi, Zhou Zhiqiang, Yin Gongzheng -- Taxonomy of the 'Micmacca' group, new Cambrian Chengkouiidae (Trilobita) from Morocco, and their bearing on intercontinental correlation / Gerd Geyer -- Revision of 'Irvingella tropica' Opik 1963 from Australia and related species from North America: Implications for correlation of the base of the Jiangshanian stage (Cambrian, Furongian) / Stephen R. Westrop, Jonathan M. Adrain -- Drumian and Guzhangian (middle Cambrian) lingulate brachiopods from Hunan province, China / Ian G. Percival, Michael J. Engelbretsen, Shanchi Peng -- Ordovician (Darriwilian-Katian) lingulate brachiopods from central New South Wales, Australia / Ian G. Percival, Michael J. Engelbretsen, Glenn A. Brock, John R. Farrell -- Emergence of the 'Saucrorthis' Fauna in the middle Ordovician of Northern Iran / Leonid E. Popov, Mohammad Reza Kebriaee-Zadeh, Mansoureh Ghobadi Pour.514 page(s
The bivalved arthropods Isoxys and Tuzoia with soft-part preservation from the Lower Cambrian Emu Bay Shale Lagerstatte (Kangaroo Island, Australia)
No full textAbundant material from a new quarry excavated in the lower Cambrian Emu Bay Shale (Kangaroo Island, South Australia) and, particularly, the preservation of soft-bodied features previously unknown from this Burgess Shale-type locality, permit the revision of two bivalved arthropod taxa described in the late 1970s, Isoxys communis and Tuzoia australis. The collections have also produced fossils belonging to two new species: Isoxys glaessneri and Tuzoia sp. Among the soft parts preserved in these taxa are stalked eyes, digestive structures and cephalic and trunk appendages, rivalling in quality and quantity those described from better-known Lagerstätten, notably the lower Cambrian Chengjiang fauna of China and the middle Cambrian Burgess Shale of Canada.Diego C. García-Bellido, John R. Paterson, Gregory D. Edgecombe, James B. Jago, James G. Gehling and Michael S. Y. Le
Guzhangian (late middle Cambrian) agnostoids and trilobites from Riana, northwestern Tasmania, Australia
No full textGuzhangian (late middle Cambrian) agnostoids and trilobites are described from near Riana, northwestern Tasmania. Five agnostoid and five trilobite species are documented. The agnostoids include a new species, which is the oldest known representative of the genus Aspidagnostus. The trilobites include Monkaspidae indet, which probably represents a new genus. The librigena of the species described as cf. Penarosa sp. appears to be unique in that it has a segmented genal spine and possesses closely spaced small, stout spines on its margins. The age of the fauna is probably within the range of Lejopyge laevigata II Zone to lower Acmarhachis quasivespa Zone, which makes it the youngest known Cambrian fauna in the Dial Range Trough.Christopher J. Bentley [[email protected]]; James B. Jago* [[email protected]], University of South Australia-STEM, Mawson Lakes, South Australia 5095, Australia
The Emu Bay Shale Konservat-Lagerstatte: a view of Cambrian life from East Gondwana
No full textRecent fossil discoveries from the lower Cambrian Emu Bay Shale (EBS) on Kangaroo Island, South Australia, have provided critical insights into the tempo of the Cambrian explosion of animals, such as the origin and seemingly rapid evolution of arthropod compound eyes, as well as extending the geographical ranges of several groups to the East Gondwanan margin, supporting close faunal affinities with South China. The EBS also holds great potential for broadening knowledge on taphonomic pathways involved in the exceptional preservation of fossils in Cambrian Konservat-Lagerstätten. EBS fossils display a range of taphonomic modes for a variety of soft tissues, especially phosphatization and pyritization, in some cases recording a level of anatomical detail that is absent from most Cambrian Konservat-Lagerstätten.John R. Paterson, Diego C. García-Bellido, James B. Jago, James G. Gehling, Michael S.Y. Lee, Gregory D. Edgecomb
Nektaspid arthropods from the lower Cambrian Emu Bay Shale Lagerstatte, South Australia, with a reassessment of lamellipedian relationships
No full textThe lower Cambrian Emu Bay Shale on Kangaroo Island, South Australia, contains the only known Cambrian Burgess Shale-type biota in Australia. Two new lamellipedian arthropods, Emucaris fava gen. et sp. nov. and Kangacaris zhangi gen. et sp. nov., from the Emu Bay Shale Lagerstätte are described as monotypic genera that are resolved cladistically as a monophyletic group that is sister to Naraoiidae + Liwiidae and classified within the Nektaspida as a new family Emucarididae. Shared derived characters of Emucarididae involve a bipartite, elongate hypostome and elongation of the pygidium relative to the cephalic shield and very short thorax. A monophyletic Liwiidae is composed of Liwia and the Ordovician Tariccoia + Soomaspis but excludes Buenaspis, and even the membership of Buenaspis in Nektaspida is contradicted amongst the shortest cladograms. New morphological interpretations favour affinities of Kwanyinaspis with Conciliterga rather than with Aglaspidida, and Phytophilaspis with Petalopleura.John R. Paterson, Gregory D. Edgecombe, Diego C. Garciá-Bellido, James B. Jago and James G. Gehlin
Taphonomy and palaeoecology of the emuellid trilobite Balcoracania dailyi (early Cambrian, South Australia)
No full textCopyright © 2007 Elsevier B.V. All rights reserved.Monospecific assemblages of the trilobite Balcoracania dailyi occur in lower Cambrian strata within the Adelaide Geosyncline in South Australia. Biostratinomic data from single bedding plane assemblages within the Warragee and Coads Hill Members of the Billy Creek Formation and White Point Conglomerate reveal a range of taphonomic signatures from census to within-habitat, time-averaged assemblages. These assemblages are interpreted as having inhabited protected, shallow, marginal marine environments. Size-frequency distributions, coupled with taphonomic data, show that the Warragee Member census assemblage represents a living population in a physically stressful environment within a tidally-influenced lagoon, while the original population structure of the Coads Hill Member and White Point Conglomerate assemblages has been lost due to varying degrees of taphonomic overprinting. Integration of taphonomic, stratigraphic and sedimentological data supports the interpretation of B. dailyi as representing an opportunistic species. A preserved body cluster from the Warragee Member assemblage is considered to characterise a congregation formed for the purpose of synchronous reproduction and ecdysis, representing one of the oldest examples of gregarious behaviour in the arthropod fossil record. Furthermore, by analogy with modern horseshoe crabs, the high number of juveniles (i.e., protaspides and early meraspides) within the same assemblage are believed to be constituents of a nursery within the intertidal zone, with adults migrating into the shallows to copulate and spawn. Preserved moult ensembles from the Coads Hill Member and White Point Conglomerate have enabled the description of exuviation techniques for B. dailyi. © 2007 Elsevier B.V. All rights reserved.John R. Paterson, James B. Jago, Glenn A. Brock and James G. Gehlinghttp://www.elsevier.com/wps/find/journaldescription.cws_home/503355/description#descriptio
Modern optics in exceptionally preserved eyes of Early Cambrian arthropods from Australia
No full textDespite the status of the eye as an "organ of extreme perfection"1, theory suggests thatcomplex eyes can evolve very rapidly2. The fossil record has, until now, been inadequate in providing insight into the early evolution of eyes during the initial radiation of many animal groups known as the Cambrian explosion. This is surprising because Cambrian Burgess-Shale-type deposits are replete with exquisitely preserved animals, especially arthropods, that possess eyes3–5. However, with the exception of biomineralized trilobite eyes, virtually nothing is known about the details of their optical design. Here we report exceptionally preserved fossil eyes from the Early Cambrian ( 515 million years ago) Emu Bay Shale of South Australia, revealing that some of the earliest arthropods possessed highly advanced compound eyes, each with over 3,000 large ommatidial lenses and a specialized ‘bright zone’.These are the oldest nonbiomineralized eyes known in such detail, with preservation quality exceeding that found in the Burgess Shale and Chengjiang deposits. Non-biomineralized eyes of similar complexity are otherwise unknown until about 85 million years later6,7. The arrangement and size of the lenses indicate that these eyes belonged to an active predator that was capable of seeing in low light. The eyes are more complex than those known from contemporaneous trilobites and are as advanced as those of many living forms. They provide further evidence that the Cambrian explosion involved rapid innovation in fine-scale anatomy as well as gross morphology, and are consistent with the concept that the development of advanced vision helped to drive this great evolutionary eventMichael S. Y. Lee, James B. Jago, Diego C. García-Bellido, Gregory D. Edgecombe, James G. Gehling and John R. Paterso
A new vetulicolian from Australia and its bearing on the chordate affinities of an enigmatic Cambrian group
No full textBACKGROUND: Vetulicolians are one of the most problematic and controversial Cambrian fossil groups, having been considered as arthropods, chordates, kinorhynchs, or their own phylum. Mounting evidence suggests that vetulicolians are deuterostomes, but affinities to crown-group phyla are unresolved. RESULTS: A new vetulicolian from the Emu Bay Shale Konservat-Lagerstätte, South Australia, Nesonektris aldridgei gen. et sp. nov., preserves an axial, rod-like structure in the posterior body region that resembles a notochord in its morphology and taphonomy, with notable similarity to early decay stages of the notochord of extant cephalochordates and vertebrates. Some of its features are also consistent with other structures, such as a gut or a coelomic cavity. CONCLUSIONS: Phylogenetic analyses resolve a monophyletic Vetulicolia as sister-group to tunicates (Urochordata) within crown Chordata, and this holds even if they are scored as unknown for all notochord characters. The hypothesis that the free-swimming vetulicolians are the nearest relatives of tunicates suggests that a perpetual free-living life cycle was primitive for tunicates. Characters of the common ancestor of Vetulicolia + Tunicata include distinct anterior and posterior body regions - the former being non-fusiform and used for filter feeding and the latter originally segmented - plus a terminal mouth, absence of pharyngeal bars, the notochord restricted to the posterior body region, and the gut extending to the end of the tail.Diego C García-Bellido, Michael S Y Lee, Gregory D Edgecombe, James B Jago, James G Gehling, and John R Paterso
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