| 1. |
- Betts, Marissa J., et al.
(författare)
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A new early Cambrian bradoriid (Arthropoda) assemblage from the northern Flinders Ranges, South Australia
- 2014
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Ingår i: Gondwana Research. - : Elsevier BV. - 1342-937X .- 1878-0571. ; 25, s. 420-437
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Tidskriftsartikel (refereegranskat)abstract
- A new assemblage of early Cambrian bivalved arthropods (Bradoriida) is described from the Arrowie Syncline in the northern Flinders Ranges, South Australia. The well preserved, largely endemic fauna comprises a total of six taxa (including five new species): Jiucunella phaseloa sp. nov., Jixinlingella daimonikoa sp. nov., Mongolitubulus anthelios sp. nov., Neokunmingella moroensis sp. nov., Phasoia cf. spicata ( Öpik, 1968), and Sinskolutella cuspidata sp. nov. This assemblage is derived from a carbonate sedimentary package representing a high energy, shallow water archaeocyath-Renalcis biohermal facies of Terreneuvian, Stage 2 age which transitions up-section to a more restricted, low energy, intra-shelf lagoonal environment that correlates with a Cambrian Series 2, Stage 3 age. The new taxon J. phaseloa sp. nov., has a first appearance datum (FAD) in shallow water biohermal facies of the Hideaway Well Member of the Wilkawillina Limestone at a level 47 m below the FAD of Pelagiella subangulata which is taken to approximate the base of Series 2, Stage 3 in South Australia. Along with Liangshanella circumbolina, this makes J. phaseloa sp. nov. amongst the oldest bivalved arthropods in South Australia and potentially greater Gondwana. The presence of 25 bradoriid taxa from the early Cambrian of South Australia suggests East Gondwana represents a major centre of origin for the Bradoriida.
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| 2. |
- Betts, Marissa, J., et al.
(författare)
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A new lower Cambrian shelly fossil biostratigraphy for South Australia
- 2016
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Ingår i: Gondwana Research. - : Elsevier BV. - 1342-937X .- 1878-0571. ; 36, s. 163-195
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Tidskriftsartikel (refereegranskat)abstract
- Definition of early Cambrian chronostratigraphic boundaries is problematic with many subdivisions stillawaiting ratification. Integrated multi-proxy data from well-resolved regional-scale schemes are ultimately the key to resolving broader issues of global correlationwithin the Cambrian. In Australia, early Cambrian biostratigraphy has been based predominantly on trilobites. Phosphatic shelly fauna have great potential as biostratigraphic tools, especially in pre-trilobitic strata because they are widespread and readily preserved, but they have remained underutilised. Here we demonstrate their value in a new biostratigraphic scheme for the early Cambrian of South Australia using a diverse shelly fauna including tommotiids, brachiopods, molluscs and bradoriids. Biostratigraphic data are derived from ten measured stratigraphic sections across the Arrowie Basin, targeting Hawker Group carbonates including the Wilkawillina, Wirrapowie and Ajax limestones and the Mernmerna Formation. The stratigraphic ranges of shelly fossils are predictable and repeatable across the Arrowie Basin, allowing three discrete shelly biozones to be identified, spanning Terreneuvian, Stage 2 to Series 2, Stages 3–4. The Kulparina rostrata Zone (new) and part of the overlyingMicrina etheridgei Zone (new) are pre-trilobitic (predominantly Terreneuvian). The Cambrian Series 2, Stage 3 Dailyatia odyssei Zone (new) features a very diverse shelly fauna and will be described in detail in a separate publication. These zones provide robust means to correlate Terreneuvian–Series 2 successions in neighbouring coeval basins in Australia, particularly the Stansbury Basin. Wider correlation is possible throughout East Gondwana, and especially with South China.
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| 3. |
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| 4. |
- Betts, Marissa, J., et al.
(författare)
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Early Cambrian chronostratigraphy and geochronology of South Australia
- 2018
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Ingår i: Earth-Science Reviews. - : Elsevier BV. - 0012-8252 .- 1872-6828. ; 185, s. 498-543
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Tidskriftsartikel (refereegranskat)abstract
- The most successful chronostratigraphic correlation methods enlist multiple proxies such as biostratigraphy and chemostratigraphy to constrain the timing of globally important bio- and geo-events. Here we present the first regional, high-resolution shelly fossil biostratigraphy integrated with δ13C chemostratigraphy (and corresponding δ18O data) from the traditional lower Cambrian (Terreneuvian and provisional Cambrian Series 2) of South Australia. The global ZHUCE, SHICE, positive excursions II and III and the CARE are captured in lower Cambrian successions from the Arrowie and Stansbury basins. The South Australian shelly fossil biostratigraphy has a consistent relationship with the δ13C results, bolstering interpretation, identification and correlation of the excursions. Positive excursion II straddles the boundary between the Kulparina rostrata and Micrina etheridgei zones, and the CARE straddles the boundary between the M. etheridgei and Dailyatia odyssei zones, peaking in the lower parts of the latter zone. New CA-TIMS zircon dates from the upper Hawker Group and Billy Creek Formation provide geochronologic calibration points for the upper D. odyssei Zone and corresponding chemostratigraphic curve, embedding the lower Cambrian successions from South Australia into a global chronostratigraphic context. This multi-proxy investigation demonstrates the power of integrated methods for developing regional biostratigraphic schemes and facilitating robust global correlation of lower Cambrian successions from South Australia (part of East Gondwana) with coeval terranes on other Cambrian palaeocontinents, including South and North China, Siberia, Laurentia, Avalonia and West Gondwana.
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| 5. |
- Betts, Marissa, J., et al.
(författare)
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Global correlation of the early Cambrian of South Australia: Shelly faunaof the Dailyatia odyssei Zone
- 2017
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Ingår i: Gondwana Research. - Amsterdam : Elsevier BV. - 1342-937X .- 1878-0571. ; 46, s. 240-279
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Tidskriftsartikel (refereegranskat)abstract
- A lack of well resolved biostratigraphic data has prevented robust regional and global correlation of lower Cambriansuccessions from South Australia. A new early Cambrian biostratigraphy, based on data derived from 21measured stratigraphic sections and drill cores (11 described herein) reveals the abundance and diversity ofshelly fauna from the Arrowie Basin, and the value of early Cambrian “small shelly fossils” (SSF) for biostratigraphicstudies. Here we examine shelly fauna associated with the youngest of three recently establishedbiozones, the Dailyatia odyssei Taxon Range Zone (hereafter D. odyssei Zone), and their correlative potential.The D. odyssei Zone features a diverse suite of tommotiids, organophosphatic brachiopods, bradoriid arthropods,molluscs and phosphatic problematica. This fauna permits strong correlation (often at species-level) with othermajor early Cambrian terranes, particularly Antarctica, South China and Laurentia, and suggest a Cambrian Series2, Stages 3–4 age for the D. odyssei Zone. Bradoriids have proven to be useful biostratigraphic tools. Four newspeciesand three new genera are described herein: Acutobalteus sinuosus gen. et sp. nov., Eozhexiella adnyamathanha gen. etsp. nov., Manawarra jonesi gen. et sp. nov. and Mongolitubulus descensus sp. nov. The description of Eohadrotreta sp.cf. zhenbaensis represents the first occurrence of the acrotretoid brachiopod Eohadrotreta from Australia.
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| 6. |
- Betts, Marissa, J., et al.
(författare)
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Shelly fossils from the lower Cambrian White Point Conglomerate, Kangaroo Island, South Australia
- 2019
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Ingår i: Acta Palaeontologica Polonica. - : Polska Akademia Nauk Instytut Paleobiologii (Institute of Paleobiology, Polish Academy of Sciences). - 0567-7920 .- 1732-2421. ; 64:3, s. 489-522
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Tidskriftsartikel (refereegranskat)abstract
- The lower Cambrian (Series 2) White Point Conglomerate (WPC) on Kangaroo Island, South Australia contains exoticclasts representing a diverse array of lithologies, including metamorphics, chert, sandstone, and abundant carbonates,notably archaeocyath-rich bioclastic limestone. Acetic acid digestion of the WPC bioclastic limestone clasts reveals adiverse shelly fauna. This assemblage includes abundant organophosphatic brachiopods such as Cordatia erinae Brockand Claybourn gen. et sp. nov., Curdus pararaensis, Eodicellomus elkaniformiis, Eohadrotreta sp. cf. E. zhenbaensis,Eoobolus sp., Kyrshabaktella davidii, and Schizopholis yorkensis. Additional shelly taxa include the solenopleurid trilobiteTrachoparia? sp., the tommotiids Dailyatia odyssei, Dailyatia decobruta Betts sp. nov., Kelanella sp., and Lapworthellafasciculata, spines of the bradoriid arthropod Mongolitubulus squamifer, and several problematica, such as Stoibostrombuscrenulatus and a variety of tubular forms. The upper age limit for the WPC is constrained by biostratigraphic data fromthe overlying Marsden Sandstone and Emu Bay Shale, which are no younger than the Pararaia janeae Trilobite Zone(Cambrian Series 2, Stage 4). The shelly fossil assemblage from the WPC limestone clasts indicates an upper Dailyatiaodyssei Zone (= Pararaia tatei to lower P. janeae trilobite zones), equivalent to the Atdabanian–early Botoman of theSiberian scheme. This contrasts with the previously suggested late Botoman age for the limestone clasts, based on the diversearchaeocyath assemblage. The minor age difference between the WPC and its fossiliferous limestone clasts suggestsrelatively rapid reworking of biohermal buildups during tectonically-active phases of deposition in the Stansbury Basin.
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| 7. |
- Bicknell, Russell D.C., et al.
(författare)
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The gnathobasic spine microstructure of recent and Silurian chelicerates and the Cambrian artiopodan Sidneyia: Functional and evolutionary implications
- 2018
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Ingår i: Arthropod structure & development. - : Elsevier BV. - 1467-8039 .- 1873-5495. ; 47, s. 12-24
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Tidskriftsartikel (refereegranskat)abstract
- Gnathobasic spines are located on the protopodal segments of the appendages of various euarthropod taxa, notably chelicerates. Although they are used to crush shells and masticate soft food items, the microstructure of these spines are relatively poorly known in both extant and extinct forms. Here we compare the gnathobasic spine microstructures of the Silurian eurypterid Eurypterus tetragonophthalmus from Estonia and the Cambrian artiopodan Sidneyia inexpectans from Canada with those of the Recent xiphosuran chelicerate Limulus polyphemus to infer potential variations in functional morphology through time. The thickened fibrous exocuticle in L. polyphemus spine tips enables effective prey mastication and shell crushing, while also reducing pressure on nerve endings that fill the spine cavities. The spine cuticle of E. tetragonophthalmus has a laminate structure and lacks the fibrous layers seen in L. polyphemus spines, suggesting that E. tetragonophthalmus may not have been capable of crushing thick shells, but a durophagous habit cannot be precluded. Conversely, the cuticle of S. inexpectans spines has asimilar fibrous microstructure to L. polyphemus, suggesting that S. inexpectans was a competent shell crusher. This conclusion is consistent with specimens showing preserved gut contents containing various shelly fragments. The shape and arrangement of the gnathobasic spines is similar for both L. polyphemusand S. inexpectans, with stouter spines in the posterior cephalothoracic or trunk appendages, respectively.This differentiation indicates that crushing occurs posteriorly, while the gnathobases on anterior appendages continue mastication and push food towards and into the mouth. The results of recent phylogenetic analyses that considered both modern and fossil euarthropod clades show that xiphosurans and eurypterids are united as crown-group euchelicerates, with S. inexpectans placed within more basalartiopodan clades. These relationships suggest that gnathobases with thickened fibrous exocuticle, if not homoplasious, may be plesiomorphic for chelicerates and deeper relatives within Arachnomorpha. This study shows that the gnathobasic spine microstructure best adapted for durophagy has remained remarkably constant since the Cambrian.
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| 8. |
- Bing, Pan, et al.
(författare)
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Biostratigraphical and palaeogeographical implications of Early Cambrian hyoliths from the North China Platform
- 2019
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Ingår i: Alcheringa. - : Informa UK Limited. - 0311-5518 .- 1752-0754. ; 43, s. 351-380
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Tidskriftsartikel (refereegranskat)abstract
- A succession of diverse hyolith assemblages comprising 10 genera and 14 species are reported from the lower Cambrian Shangwan and Sanjianfang sections of the Xinji Formation, and Xiaomeiyao section of the Houjiashan Formation, which crop out along the southern margin of the North China Platform. Most of the specimens are represented by both conchs and opercula. The identified orthothecids include Conotheca australiensis, Cupitheca holocyclata, C. costellata, Neogloborilus applanatus, N. spinatus, Tegminites hymenodes, Triplicatella disdoma, T. xinjia sp. nov. and Paratriplicatella shangwanensis gen. et sp. nov. The hyolithids comprise Protomicrocornus triplicensis gen. et sp. nov., Microcornus eximius, M. petilus, Parkula bounites and Parakorilithes mammillatus. Some anomalous taxa possess characteristics of both Hyolithida and Orthothecida, such as C. australiensis, Neogloborilus and P. triplicensis. Protomicrocornus may constitute a sister group of other hyolithids. The teeth of Parkula bounites and clavicles of Parakorilithes mammillatus are documented for the first time. The hyolith assemblages from North China are probably coeval, and can be correlated with the Cambrian upper Stage 3–lower Stage 4. Many taxa are also globally distributed and have significant potential for biostratigraphical correlations. In accordance, the hyoliths from North China reveal closest compositional similarities to faunas from eastern Gondwana, and especially South Australia. However, some taxa are shared with Laurentian assemblages suggesting cosmopolitanism, and possibly planktonic larval dispersal.
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| 9. |
- Chen, Feiyang, et al.
(författare)
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Cambrian ecological complexities: Perspectives from the earliest brachiopod – supported benthic communities in the early Cambrian Guanshan Lagerstätte
- 2022
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Ingår i: Gondwana Research. - Amsterdam : Elsevier. - 1342-937X .- 1878-0571. ; 107, s. 30-41
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Tidskriftsartikel (refereegranskat)abstract
- The Cambrian radiation is characterized by the emergence of diverse bilaterian animal phyla and theestablishment of complex marine ecosystems. The Guanshan Biota records an unusual ecological transition from trilobite- to brachiopod-dominated communities during Cambrian Stage 4. This community transition is accompanied by direct evidence of in situ biological interactions such as durophagous pre-dation and kleptoparasitism. Here we describe new material from the Guanshan biota, focusing on an association of palaeoscolecidomorphs and brachiopods with parasitic tube worms that occur on micro-bedding planes. The bedding plane assemblages are dominated by the organophosphatic brachiopod Neobolus wulongqingensis encrusted with kleptoparasitic tube-dwelling worms, along with infaunal palaeoscolecidans. Taphonomic and sedimentological evidence indicates that these specimens are com-monly preserved in life position, and thus the association between individuals represent potential biological interactions. This case study reveals that ecosystems during the early Cambrian exhibited a well-developed system of tiering and a complex trophic network, easily distinguished from the simple communities typical of precursor deposits in the Ediacaran. Brachiopods forming extremely dense concentrations on the sea floor are effectively acting as ecosystem engineers, not only to stabilize the soft-substrate seafloor, but also act as an alternative substrate for the oldest empirically demonstrated kleptoparasites.The in situ biological interactions preserved in the Guanshan Biota are critical for filling gaps in ourknowledge of ecosystem complexity in the Cambrian.
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| 10. |
- Claybourn, Thomas, 1989-, et al.
(författare)
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Camenellan tommotiids from the Cambrian Series 2 of East Antarctica: biostratigraphy, palaeobiogeography, and systematics
- 2021
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Ingår i: Acta Palaeontologica Polonica. - : Instytut Paleobiologii PAN. - 0567-7920 .- 1732-2421. ; 66, s. 207-229
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Tidskriftsartikel (refereegranskat)abstract
- Cambrian Series 2 shelly fossils from thick carbonate successions in East Antarctica have received limited systematic treatment through the 20th century. Described here are the East Antarctic camenellan tommotiids from the Shackleton Limestone in the Central Transantarctic Mountains and the Schneider Hills limestone in the Argentina Range. This material comes from both newly sampled collections and incompletely described material from older collections. The assemblage supports correlation to the Dailyatia odyssei Zone and Pararaia janeae Trilobite Zone of South Australia, with the newly examined specimens of Dailyatia decobruta from the Shackleton Limestone providing direct correlation to the Mernmerna Formation of the Ikara-Flinders Ranges and White Point Conglomerate of Kangaroo Island. These East Antarctic assemblages include five species referred to Dailyatia, in addition to an undetermined kennardiid species and fragments of the problematic Shetlandia multiplicata. The results further corroborate the notion that fossiliferous carbonate clasts found on King George Island were sourced from the same carbonate shelf as the Shackleton Limestone, with the taxon S. multiplicata found in both units. The Schneider Hills limestone in the Argentina Range has yielded sclerites of Dailyatia icari sp. nov., currently only known from this location.
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