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1.
  • Davies, J. I., et al. (författare)
  • Global surgery, obstetric, and anaesthesia indicator definitions and reporting: An Utstein consensus report
  • 2021
  • Ingår i: Plos Medicine. - : Public Library of Science (PLoS). - 1549-1277 .- 1549-1676. ; 18:8
  • Tidskriftsartikel (refereegranskat)abstract
    • Background Indicators to evaluate progress towards timely access to safe surgical, anaesthesia, and obstetric (SAO) care were proposed in 2015 by the Lancet Commission on Global Surgery. These aimed to capture access to surgery, surgical workforce, surgical volume, perioperative mortality rate, and catastrophic and impoverishing financial consequences of surgery. Despite being rapidly taken up by practitioners, data points from which to derive the indicators were not defined, limiting comparability across time or settings. We convened global experts to evaluate and explicitly define-for the first time-the indicators to improve comparability and support achievement of 2030 goals to improve access to safe affordable surgical and anaesthesia care globally. Methods and findings The Utstein process for developing and reporting guidelines through a consensus building process was followed. In-person discussions at a 2-day meeting were followed by an iterative process conducted by email and virtual group meetings until consensus was reached. The meeting was held between June 16 to 18, 2019; discussions continued until August 2020. Participants consisted of experts in surgery, anaesthesia, and obstetric care, data science, and health indicators from high-, middle-, and low-income countries. Considering each of the 6 indicators in turn, we refined overarching descriptions and agreed upon data points needed for construction of each indicator at current time (basic data points), and as each evolves over 2 to 5 (intermediate) and >5 year (full) time frames. We removed one of the original 6 indicators (one of 2 financial risk protection indicators was eliminated) and refined descriptions and defined data points required to construct the 5 remaining indicators: geospatial access, workforce, surgical volume, perioperative mortality, and catastrophic expenditure. A strength of the process was the number of people from global institutes and multilateral agencies involved in the collection and reporting of global health metrics; a limitation was the limited number of participants from low- or middle-income countries-who only made up 21% of the total attendees. Conclusions To track global progress towards timely access to quality SAO care, these indicators-at the basic level-should be implemented universally as soon as possible. Intermediate and full indicator sets should be achieved by all countries over time. Meanwhile, these evolutions can assist in the short term in developing national surgical plans and collecting more detailed data for research studies.
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2.
  • Andersson, Ki, 1975- (författare)
  • Aspects of locomotor evolution in the Carnivora (Mammalia)
  • 2003
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • In this thesis, the shape of the distal humerus trochlea is analysed using landmark-based morphometrics and multivariate methods, with the aim of exploring locomotor evolution in carnivorans. Elbow joint morphology is used together with body size and craniodental morphology to characterize past and present carnivorans. Evolutionary implications are studied at the ordinal, familial, and species levels, testing specific hypotheses about scaling, morphological constraints, evolutionary trajectories, and potential for social pack-hunting behaviour. The circumference of the distal humerus trochlea is found to be highly correlated with body mass, and appears to scale similarly throughout the order Carnivora. A general predictive model for carnivoran bodymass is presented (a=0.601; b= 2.552; r2=0.952, SEE=0.136, p<0001, n=92), which removes the need for the investigator to actively choose between the diverging estimates that different predictors and their equations often produce. At the elbow joint, manual manipulation and locomotion appear to be conflicting functions, thus suggesting mutually exclusive lifestyles involving either forelimb grappling or pursuit. At large body sizes, carnivorans are distributed over a strongly dichotomised pattern (grappling or locomotion), a pattern coinciding with the postulated threshold in predator-prey size ratio at 21.5-25 kg. This pattern is compared to that of two carnivoran faunas from the Tertiary. In the Oligocene (33.7-23.8 Myr BP), the overall pattern is remarkably similar to that observed for extant Carnivora. In the Miocene (23.8-11.2 Myr BP) carnivores show a similarly dichotomised pattern as the Oligocene and Recent, although the whole pattern is shifted towards larger body sizes. This difference is suggested to be a reflection of the extraordinary species richness of browsing ungulates in the early Miocene of North America. Such an increase in prey spectrum would create a unique situation, in which large carnivores need not commit to a cursorial habitus in order to fill their nutritional requirements. Finally, the elbow joints and craniodental morphology (14 measurements) of fossil canids were examined with the aim of assessing the potential for pack-hunting in fossil canids. It is clear that small and large members of the Recent Caninae share similar craniodental morphologies. However, this pattern is not present in Borophaginae and Hesperocyoninae. In the latter, large representatives are characterized by being short-faced, with reduced anterior premolars and enlarged posterior premolars, thus approaching a “pantherine-like” craniodental configuration. These traits are interpreted as an adaptation for killing prey with canine bites. It is similarly determined that, unlike recent Caninae, all analyzed species of borophagines and hesperocyonines have retained the ability to supinate their forearms. It is therefore likely that manual manipulation was part of their hunting behaviour, thus removing an essential part of the argument for social pack-hunting in these forms, as the benefits of such a strategy become less obvious.
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3.
  • Streng, Michael, 1971-, et al. (författare)
  • Columnar shell structures in early linguloid brachiopods : new data from the Middle Cambrian of Sweden
  • 2008
  • Ingår i: Earth and Environmental Science Transactions of the Royal Society of Edinburgh. - 1755-6910. ; 98:Part 3-4, s. 221-232
  • Tidskriftsartikel (refereegranskat)abstract
    • The records of columnar shell structures of linguloid brachiopods (Class Lingulata, Order Lingulida, Superfamily Linguloidea) are reviewed in the light of the discovery of two new taxa from the Middle Cambrian Forsemölla Limestone Bed of southern Sweden. The linguloid taxa, described here as Eoobolus? sp. aff. E. priscus (Poulsen) and Canalilatus? simplex sp. nov., are both characterised by a columnar shell structure, a structural type that is representative for acrotretoid brachiopods and that has previously only rarely been reported from the linguloids. Though the two taxa are superficially similar to known genera, i.e., Eoobolus and Canalilatus, their shell structure challenges such affiliations, as the shell structure of the type species of these genera is previously unknown. Linguloid families whose morphological characteristics agree the most with those of the new taxa, i.e., the Zhanatellidae and the Eoobolidae, and from which columnar shell structures have been reported, i.e., the Lingulellotretidae and the Kyrshabaktellidae, are reviewed briefly. Many taxa assigned to these families completely lack shell structure data and are in need of restudy in order to elucidate their systematic position. Knowledge of the representative type of shell structure of the various suprageneric taxa within the Linguloidea is considered crucial, in order to unravel their currently poorly resolved phylogenetic relationships.
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4.
  • Wang, Haizhou, et al. (författare)
  • Peduncular attached secondary tiering acrotretoid brachiopods from the Chengjiang fauna : Implications for the ecological expansion of brachiopods during the Cambrian explosion
  • 2012
  • Ingår i: Palaeogeography, Palaeoclimatology, Palaeoecology. - : Elsevier BV. - 0031-0182 .- 1872-616X. ; 323-325, s. 60-67
  • Tidskriftsartikel (refereegranskat)abstract
    • Brachiopods are usually thought to contribute little to the tiering complexity from the Paleozoic to the Recent, mainly due to the fact that their recent representatives live primarily in lower tiers directly above or below the water-sediment interface. Here we present the first and oldest record of varied levels of secondary tiering in minute brachiopods attached by exceptionally preserved thread-like pedicles around the branched fronds of the algae-like Malongitubus kuangshanensis Hu, 2005. The specimens illustrated herein were recovered from the Chengjiang fauna (Series 2, Stage 3) in the Lower Cambrian Heilinpu Formation at the Kuangshan section in Malong County, Yunnan Province, southern China. The micro-morphology and oval outline of the attached brachiopods demonstrate that they can be assigned to acrotretoid brachiopods (Linguliformea, Lingulata, Acrotretoidea), described here as Kuangshanotreta malungensis gen. et sp. nov. This is the first report on the occurrence of acrotretoid brachiopods in the Lower Cambrian muddy deposits from southern China. The posterior margins of the Kuangshanotreta shells are invariably either in direct contact with, or directed towards, and then in situ attached to the algal frond of M. kuangshanensis, indicating a secondary tiering in the ecological structure of Early Cambrian brachiopods. The acrotretoid Kuangshanotreta/algae malongitubus association represents both the first and oldest evidence into the enigmatic paleoecology of the diverse acrotretoid linguliformean stock that comprises an important component of the Cambrian evolutionary fauna, and sheds light on medium-high levels of secondary tiering (+5 to +10 cm) Cambrian soft substrate suspension-feeding communities. When compared to other Chengjiang brachiopods, the miniature morphology and concomitant weight reduction of the shell of K. malungensis may be a good adaption to a suspended epifaunal tiering life style. We infer that the diversification of micromorphic and miniaturized acrotretoids that occurred from the Middle Cambrian to Early Ordovician may be the result of the increased availability of habitable surfaces provided by high levels of tiering in new types of ecological spaces.
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5.
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6.
  • Álvaro, J. Javier, et al. (författare)
  • Submarine metalliferous carbonate mounds in the Cambrian of the Baltoscandian Basin induced by vent networks and water column stratification
  • 2022
  • Ingår i: Scientific Reports. - : Springer Nature. - 2045-2322. ; 12:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Two massive precipitation events of polymetallic ore deposits, encrusted by a mixture of authigenic carbonates, are documented from the Cambrian of the semi-enclosed Baltoscandian Basin. δ34S (‒9.33 to ‒2.08‰) and δ33S (‒4.75 to ‒1.06‰) values from the basal sulphide breccias, sourced from contemporaneous Pb–Zn–Fe-bearing vein stockworks, reflect sulphide derived from both microbial and abiotic sulphate reduction. Submarine metalliferous deposits were triggered by non-buoyant hydrothermal plumes: plumes of buoyant fluid were trapped by water column stratification because their buoyancy with respect to the environment reversed, fluids became heavier than their surroundings and gravitational forces brought them to a halt, spreading out laterally from originating vents and resulting in the lateral dispersion of effluents and sulphide particle settling. Subsequently, polymetallic exhalites were sealed by carbonate crusts displaying three generations of ikaite-to-aragonite palisade crystals, now recrystallized to calcite and subsidiary vaterite. Th of fluid inclusions in early calcite crystals, ranging from 65 to 78 ºC, provide minimum entrapment temperatures for carbonate precipitation and early recrystallization. δ13Ccarb (‒1.1 to + 1.6‰) and δ18Ocarb (‒7.6 to ‒6.5‰) values are higher than those preserved in contemporaneous glendonite concretions (‒8.5 to ‒4.7‰ and ‒12.4 to ‒9.1‰, respectively) embedded in kerogenous shales, the latter related to thermal degradation of organic matter. Hydrothermal discharges graded from highly reduced, acidic, metalliferous, and hot (~ 150 ºC) to slightly alkaline, calcium-rich and warm (< 100 ºC), controlling the precipitation of authigenic carbonates.
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7.
  • Betts, Marissa J, et al. (författare)
  • Integrated chronostratigraphy of the lower Cambrian Byrd Group, Transantarctic Mountains
  • Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
    • Antarctica and Australia were sutured together straddling the equator during the major pulse of animal biodiversification associated with the Cambrian radiation. However, lack of detailed systematic sampling of lower Cambrian sedimentary packages from Antarctica has significantly impeded precise age determination and correlation with other Cambrian paleocontinents, especially with other parts of East Gondwana. Here were present new, integrated biostratigraphic and chemostratigraphic (δ13C isotopes) data from three stratigraphic sections measured through autochthonous shallow water carbonates (including archaeocyath-microbial bioherms) from the lower Cambrian Byrd Group in the Transantarctic Mountains. Recovered shelly fossil assemblages (brachiopods, tommotiids, molluscs, trilobites) from the Holyoake and Churchill Ranges include conspecific taxa previously described from Hawker Group rocks in the Arrowie Basin of South Australia facilitating direct correlation with the upper Dailyatia odyssei biozone. Synchronous chemostratigraphic data capture a distinctive positive ?13C excursion in the Churchill Range interpreted as the global Mingxinsi Carbon Isotope Excursion (MICE) peak. A succeeding gradual negative ?13C excursion captured in the Churchill and Holyoake sections is interpreted as the global Archaeocyathid Extinction Carbon Isotope Excursion (AECE) event. There is no chemostratigraphic evidence for the large Redlichiid-Olenellid Extinction Carbon Isotope Excursion (ROECE) negative event that straddles and defines the Cambrian Stage 4 – Miaolingian boundary. Hence, the integrated faunal and new chemostratigraphic data presented herein strongly support a Cambrian Stage 4 age for the upper Shackleton Limestone – Holyoake Formation – Starshot Formation succession of the Byrd Group.
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8.
  • Butler, Aodhán D., et al. (författare)
  • Exceptionally preserved Mickwitzia from the Indian Springs Lagerstätte (Cambrian Stage 3), Nevada
  • 2015
  • Ingår i: Journal of Paleontology. - : Cambridge University Press (CUP). - 0022-3360 .- 1937-2337. ; 89:6, s. 933-955
  • Tidskriftsartikel (refereegranskat)abstract
    • ABSTRACT Exceptionally preserved specimens of the Cambrian stem-group brachiopod Mickwitzia occidens Walcott, 1908 are described in detail from the Indian Springs LagerstÀtte in Nevada, USA. Shell structure and preserved mantle setae from these specimens reveal a variable diagenetic (taphonomic) history and provide insight into the phylogenetic position of mickwitziids. Morphologic and morphometric comparison to M. monilifera (Linnarsson, 1869) from Sweden and M. muralensis Walcott, 1913 from British Columbia, Canada reveals clear species-level distinctions. Scanning electron microscopic analysis allows revision of the generic diagnosis. The Mickwitzia shell is characterized by the presence of inwardly pointing phosphatic cones and tangential setae-bearing tubes. The inwardly pointing cone structures are not consistent with setal bearing structures as previously thought, but rather represent endopunctae-like structures. Acrotretid-like shell structures and shell-penetrating setae in M. occidens strengthen the previously proposed close relationship between stem-group brachiopods and tommotiids, a group of small shelly fossils.
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9.
  • Hairapetian, Vachik, et al. (författare)
  • Ordovician of the Anarak Region : implications in understanding Early Palaeozoic history of Central Iran
  • 2015
  • Ingår i: Stratigraphy. - 1547-139X .- 2331-656X. ; 12:2, s. 22-30
  • Tidskriftsartikel (refereegranskat)abstract
    • The Pol-e Khavand area south-east of the town of Anarak preserves important clues for understanding geological evolution of Central Iran during the Palaeozoic. New observations confirm the non-conformable relationship between Doshakh metamorphites and overlying unmetamorphosed Lower Palaeozoic sediments, suggesting accretion of the volcanic arc in front of the Yazd block sometime in the late Cambrian to early Ordovician. The newly introduced volcano-sedimentary Polekhavand Formation preserves evidence of a ?Late Cambrian to Early Ordovician post-collisional bimodal volcanism and related extensional regime in the Pol-e Khavand area during that time. The Middle to Upper Ordovician interval of the studied succession is assigned to the newly introduced Chahgonbad Formation. The Darriwilian age of the base of this lithostratigraphical unit is demonstrated by the brachiopods Tritoechia and Yangtzeella which co-occur with a diverse a cephalopod assemblage. The low diversity fauna including brachiopods Hibernodonta sp., Hindella sp., Rostricellula cf. ambigena and trilobites Vietnamia cf. teichmulleri suggest a Katian age for the upper part of the unit. There is insufficient evidence for the existence of the hypothetical Palaeo Tethys suture zone south of the Pol-e Khavand area.
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10.
  • Harper, David A.T., et al. (författare)
  • Brachiopods : origin and early history
  • 2017
  • Ingår i: Palaeontology. - : Wiley. - 0031-0239 .- 1475-4983. ; 60:5, s. 609-631
  • Tidskriftsartikel (refereegranskat)abstract
    • Despite many major advances in recent years, three key challenges remain in bringing clarity to the early history of the phylum: (1) identifying the origin, morphology and life modes of the first brachiopods; (2) understanding the relationships of the major groups to each other and higher sister taxa; and (3) unravelling the roles of the Cambrian and Ordovician radiations that set the agenda for much of subsequent brachiopod evolution. Since some 95% of all brachiopod taxa are extinct, the fossil record is the primary source of data to frame and test models for the evolution of the phylum. The acquisition of new, and the redescription of existing faunas, in precise spatial and temporal frameworks, using new and well-established analytical and investigative techniques, are as important as ever.
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11.
  • Holmer, Lars E., 1960-, et al. (författare)
  • Cambrian rhynchonelliform nisusioid brachiopods : phylogeny and distribution
  • 2019
  • Ingår i: Papers in Palaeontology. - : John Wiley & Sons. - 2056-2799 .- 2056-2802. ; 5:3, s. 559-575
  • Tidskriftsartikel (refereegranskat)abstract
    • A comprehensive review and phylogenetic analysis of genera and species presently assigned to the rhynchonelliform superfamily Nisusioidea and family Nisusiidae suggests that this short-lived but important group of brachiopods first appeared in peri-Gondwana during the second half of the Cambrian Series 2, before going extinct by the end of Drumian times. Nisusiides achieved their maximum morphological disparity and geographical distribution during the Wuliuan Age, and Laurentia was probably the major centre of their dispersal. A new phylogenetic analysis suggests an early separation of the lineages of spinose and non-spinose nisusiids. The non-spinose nisusiids probably evolved in Laurentia by the end of Cambrian Series 4. The new nisusiid genus Bellistrophia is described. The new species Nisusia multicostata represents the first documented rhynchonelliform (kutorginide) brachiopod from the Miaolingian (Drumian) of the Alborz Mountains, Iran.
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12.
  • Holmer, Lars E., 1960-, et al. (författare)
  • Cambrian (Stage 4 to Wuliuan) brachiopods from Sonora, Mexico
  • 2022
  • Ingår i: Journal of Paleontology. - : Cambridge University Press. - 0022-3360 .- 1937-2337. ; , s. 1-21
  • Tidskriftsartikel (refereegranskat)abstract
    • The Cambrian successions at the Chihuarruita Hill outcrop, Sonora, Mexico, have yielded two successive linguliform brachiopod assemblages that are transitional between Cambrian Stage 4 and the newly recognized global Wuliuan Stage. The lowermost assemblage includes Dictyonina sp., Paterina sp., Eothele sp., Hadrotreta rara? (Cooper), and Linnarssonia arellanoi? (Cooper), coming from the upper part of the Buelna Formation. The younger, recently named El Gavilán Formation contains a more diverse linguliform brachiopod assemblage, including Acrothele concava Cooper, Batenevotreta? mexicana n. sp., Dictyonina minutipuncta Cooper, Eothele sp., Eoobolus sp., Hadrotreta rara? (Cooper), Linnarssonia arellanoi? (Cooper), Micromitra sp., Paterina sp., and Prototreta sp. The El Gavilán Formation contains a diverse trilobite fauna suggesting Delamaran age in terms of the Laurentian regional stratigraphical scheme. The base of the global Wuliuan Stage and Miaolingian Series is defined by the first occurrence of Oryctocephalus indicus; in the absence of the index species, the base should be provisionally placed at the base of the El Gavilán Formation. The Wuliuan age of the brachiopod assemblage recovered from the El Gavilán Formation is supported by the occurrence of Acrothele in the Cambrian biostratigraphical succession of Himalaya, where the genus makes its first appearance in the Kaotaia prachina Zone. In addition, the co-occurrences of Acrothele and Eothele can be taken as an indication of the Wuliuan age of the fauna. A new biogeographic analysis confirms that the Eothele Fauna first appeared at the end of Cambrian Stage 4, as a result of increased faunal migration within the southern tropical latitudes directed from Australasian Gondwana to Laurentia.
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13.
  • Holmer, Lars E, et al. (författare)
  • Early Ordovician organophosphatic brachiopods with Baltoscandian affinities from the Alay Range, southern Kyrgyzstan
  • 2000
  • Ingår i: GFF. - : Informa UK Limited. - 1103-5897 .- 2000-0863. ; 122:4, s. 367-375
  • Tidskriftsartikel (refereegranskat)abstract
    • Organophosphatic-shelled brachiopods (Subphylum Linguliformea, Class Lingulata) of early Ordovician (Arenig) age are described for the first time from carbonate olistoliths within the Silurian Pulgon Formation of the Kichik Alay Range, southern Kyrgyzstan. The assemblages include Paterula? naukatensis sp. nov., Rowellella sp., Orbithele ceratopygarum (Brgger), Acrotreta korynevskii Holmer & Popov, Ombergia mirabilis gen. et sp. nov., Eoconulus cf.primus Popov & Holmer, and Palaeoglossa? aff. razumovskii (Lermontova). The Kyrgyzstanian faunas appear to correlate mainly with assemblages from the upper Hunnebergian or lower Billingenian regional stages of Baltoscandia. Taxa in common with those from the early Arenig of Baltoscandia and the South Urals include O. ceratopygarum and A. korynevskii. Ombergia mirabilis is known otherwise only from coeval strata in Baltoscandia. It is probable that the Kyrgyzstanian olistoliths originated from early Ordovician intra-oceanic volcanic island arcs in the proximity of Gondwana, and the microbrachiopod faunas around these islands may have given rise to the more widespread and richer faunas that spread across Baltica during the rest of the Ordovician, as the island complexes drifted towards Baltica.
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14.
  • Holmer, Lars E., et al. (författare)
  • Ecology, biofacies, biogeography and systematics of micromorphic lingulate brachiopods from the Ordovician (Darriwilian–Sandbian) of south-central China
  • 2017
  • Ingår i: Papers in Palaeontology. - : Wiley. - 2056-2799 .- 2056-2802. ; 3:3, s. 317-361
  • Tidskriftsartikel (refereegranskat)abstract
    • Ordovician (Darriwilian to Sandbian) micromorphic linguliform lingulate brachiopods are described from the Guniutan Formation at the Fenxiang section in Hubei province, and the Maocaopu and Cili sections in Hunan province of south-central China, situated on the Yangtze Platform. A total of 7560 specimens from 155 limestone samples (within the interval of Lenodus variabilis – Pygodus anserinus biozones) are assigned to 22 species, representing a low taxonomic diversity and low abundance fauna. The fauna is dominated by the Acrotretoidea, mainly species of the Torynelasmatidae, with Torynelasma the most abundant (more than 40% of total number of specimens), along with the Eoconulidae and Eoconulus (18% of total) representing the second most common forms. Species of the Ephippelasmatidae are also common (16% of total) diverse, and include representatives of Myotreta and Numericoma, as well as Ephippelasma, whereas species of the Scaphelasmatidae are somewhat less common (13% of total). All three investigated sections represent outer shelf environments, but the Maocaopu section is situated in a relatively deeper position, in proximity of the south-eastern outer margin of the Upper Yangtze Platform, close to its boundary with the Jiangnan Slope. A quantitative analysis of the relative abundance data was carried out in order to investigate the biofacies distribution of the micromorphic brachiopod communities across the Yangtze Platform, something that has not been attempted before with Palaeozoic linguliforms. Six lingulate microbrachiopod communities could be recognized in the sections. The major biofacies shift, which occurred in the Cili section in the upper part of the Microzarkodina ozarkodella Zone, at the time of the onset and initial rise of the Mid Darriwilian Carbon Isotope Excursion (MDICE) suggests that these biofacies may have been depth controlled.
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15.
  • Holmer, Lars E., 1960-, et al. (författare)
  • Evolutionary significance of a middle Cambrian (Series 3) in situ occurrence of the pedunculate rhynchonelliform brachiopod Nisusia sulcata
  • 2018
  • Ingår i: Lethaia. - : Scandinavian University Press / Universitetsforlaget AS. - 0024-1164 .- 1502-3931. ; 51:3, s. 424-432
  • Tidskriftsartikel (refereegranskat)abstract
    • Exceptionally preserved, silicified and articulated complete shells of the rhynchonelliform kutorginate brachiopod Nisusia sulcata are redescribed from the middle Cambrian (Series 3) Marjum Limestone, Utah. Cylindroid sausage-like protrusions, emerging posteriorly between the valves, were originally interpreted as faecal in origin, but restudy under the SEM shows that these features represent silicified pedicles as they are attached in situ to other Nisusia. The Nisusia host most likely was alive at the time of attachment. Restudy of the pedicles of Nisusia provides new phylogenetic information on the anatomy of the earliest rhynchonelliforms. The silicified pedicles differ considerably from the pedicles of living crown group rhynchonelliforms in being strongly annulated, distally tapering, and were likely to have been rather more flexible. The Nisusia pedicles are more similar to the exceptionally preserved pedicles from other Cambrian rhynchonelliform brachiopods, including Kutorgina, Longtancunella and Alisina, but these emerge from the ventral apical foramen rather than from between the valves as in Nisusia. Although generally similar, these two types of pedicles are unlikely to represent homologous structures as Nisusia is provided with both an apical foramen (possibly larval attachment) and a posterior adult pedicle. The similarities may be explained by similar type of accretionary growth from two different types of epithelia. The Nisusia-like pedicle appeared early within the kutorginates and rhynchonellates. The discovery of hollow spines in Nisusia sulcata further supports the generic assignation of the species.
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16.
  • Holmer, Lars E., 1960-, et al. (författare)
  • Linguliform brachiopods from the Cambrian (Guzhangian) Karpinsk Formation of Novaya Zemlya
  • 2020
  • Ingår i: Papers in Palaeontology. - : John Wiley & Sons. - 2056-2799 .- 2056-2802. ; 6:4, s. 571-592
  • Tidskriftsartikel (refereegranskat)abstract
    • Abstract A moderately diverse assemblage of micromorphic linguliform brachiopods, including Tapuritreta gribovensis sp. nov., Wahwahlingula? pankovensis sp. nov., Acrothele sp., Anabolotreta? sp., Orbithele? sp. and Stilpnotreta sp., is for the first time described from the Cambrian Karpinsk Formation (Miaolingian, Guzhangian) of the South Island of Novaya Zemlya. The morphology of the metamorphic shell in Acrothele and Wahwahlingula? suggest that both taxa had a single pair of larval setal sacs, similar to the recent discinids, but their metamorphosis was completed only at the end of the pelagic stage and shows that they did have direct development, which is characteristic of all recent lingulides. The biogeographical signature of the new Cambrian brachiopod fauna from Novaya Zemlya is discussed, and the new fauna gives new information on the poorly known Cambrian margins of the Baltica palaeocontinent.
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17.
  • Holmer, Lars E., et al. (författare)
  • Lower Ordovician (Tremadocian) lingulate brachiopods from the House and Fillmore formations, Ibex Area, western Utah, USA
  • 2005
  • Ingår i: Journal of Paleontology. - 0022-3360 .- 1937-2337. ; 79:5, s. 884-906
  • Tidskriftsartikel (refereegranskat)abstract
    • Seven genera and eight species of lingulate brachiopods were recovered from the House Limestone and lower Fillmore Formation, Ibex area, Utah, USA. These strata are assigned to the upper Skullrockian Stage and lower Stairsian Stage of the Ibexian Series (Iapetognathus Conodont Zone to Low Diversity Interval) and are correlated with the Tremadocian Series of the Acado–Baltic Faunal Province. The fauna includes two new linguloid species, Spinilingula prisca and Wahwahlingula sevierensis, one new siphonotretoid species, Schizambon obtusus, and two new acrotretoid species, Eurytreta fillmorensis and Ottenbyella ibexiana. The last species is the first record of the genus in North America and suggests a correlation of the basal Fillmore Formation with the Ceratopyge Limestone in Sweden. A Siphonobolus? covered by long hollow spines may be one of the oldest siphonotretides with such ornament. This fauna and those described previously from older Utah strata document the biodiversification of the Cambrian–Ordovician lingulate brachiopods and demonstrate their potential for regional and intercontinental correlation.
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18.
  • Holmer, Lars E., et al. (författare)
  • Reassessment of the early Triassic lingulid brachiopod ‘Lingula’ borealis Bittner, 1899 and related problems of lingulid taxonomy
  • 2016
  • Ingår i: GFF. - : Informa UK Limited. - 1103-5897 .- 2000-0863. ; 138:4, s. 519-525
  • Tidskriftsartikel (refereegranskat)abstract
    • The Early Triassic (late Induan to early Olenekian) Lingula borealis Bittner, from the Russkii Island on the Pacific cost of south-eastern Russia is revised, based on re-examination of the type material. Although this species, like most described Triassic lingulids, has remained very poorly understood due to the lack of information on important characters, such as musculature and mantle canals, it has been commonly recorded in subsequent studies and included in attempts at understanding the patterns of extinction and recovery at around the Permian-Triassic boundary. Linguliform brachiopods are some of the notable survivors of this significant mass extinction event. Lingula borealis has previously been referred to Lingularia and provisionally synonymised with Lingularia similis Biernat & Emig. Here, it is shown that it differs from Lingularia similis mainly in characters of mantle canals, musculature and most importantly in details of the pedicle nerve impression. In Lingularia borealis, the impression of the pedicle nerve is symmetrical and goes almost straight between the individual ventral umbonal muscle scars, whereas in Lingularia similis it is asymmetrically positioned towards the smaller left component of the ventral umbonal muscle scar. Shell structures and details of preserved ontogenies have also proven to be important for the discrimination of lingulid taxa, but cannot be provided from the types of Lingularia borealis.
  •  
19.
  • Holmer, Lars E., 1960-, et al. (författare)
  • Unusual pitted Ordovician brachiopods from the East Baltic : the significance of coarsely pitted ornamentations in linguliforms
  • 2017
  • Ingår i: Papers in Palaeontology. - : Wiley. - 2056-2799 .- 2056-2802. ; 3:3, s. 387-399
  • Tidskriftsartikel (refereegranskat)abstract
    • A characteristic coarsely pitted ornamentation (with pits larger than 0.015 mm across) can be found on some very enigmatic and rare Lower Ordovician phosphatic-shelled linguliform brachiopods, including the paterinid Lacunites balaschovae Gorjansky and the obolid Foveola maarduensis Gorjansky. Both of these species are poorly understood and known from only a few specimens from the Floian of the East Baltic. Here we describe the Ordovician species Lacunites ivantsovi sp. nov. from the lower Darriwilian of the St Petersburg region and Foveola ivari sp. nov. from the Sandbian of Estonia, representing the last known survivors of these genera in the area. The new Darriwilian species of Lacunites is also one of the last members of the Class Paterinata, which most importantly includes some of the earliest known brachiopods from the early Cambrian. The coarsely pitted ornamentation of Foveola ivari is associated with the formation of asymmetrical so-called terrace lines in the umbonal area. The latter may indicate a burrowing life style. The pits in Lacunites and Foveola are directly comparable to the more or less identical coarse pits in the discinoid Trematis. Unlike the microscopic pits found in many fossil linguliforms, it is most likely that the coarse pits were empty in life; the minute surface ornamentation of irregular wrinkles in the outer primary layer continues across the bottom of the depressions in Foveola and Trematis; in the latter the cementing attachment discs of an attached phosphatic tubular Byronia-like organism also extend down into the pits.
  •  
20.
  • Jahangir, Hadi, et al. (författare)
  • Biostratigraphy of the Cambrian–Ordovician boundary beds at Kopet-Dagh, Iran
  • 2015
  • Ingår i: Stratigraphy. - 1547-139X .- 2331-656X. ; 2:12, s. 40-47
  • Tidskriftsartikel (refereegranskat)abstract
    • A continuous succession comprising upper Cambrian (Furongian) to Lower Ordovician (Tremadocian) conodont biozones is reported for the first time from the Kopet-Dagh Region of northeastern Iran. Seven biostratigraphical units are recognized, including the Proconodontus tenuiserratus and Proconodontus posterocostatus zones; these two lowermost biostratigraphical units are defined by euconodont species which have not been previously reported from Iran and temperate latitude peri-Gondwana. The conodont diversity and abundance decreased significantly above the Eoconodontus notchpeakensis Zone; the conodont faunas of the succeeding Cordylodus proavus, Cordylodus lindstromi (sensu lato) and Cordylodus angulatus zones are characterised by oligotaxic to monotaxic associations dominated by species of Cordylodus. In the absence of diagnostic conodont species, the position of the lower boundary of the Ordovician System in the Kalat Valley Section can be placed somewhat below the first occurrence of the early planktonic graptolite Rhabdinopora flabelliformis, which approximately coincides with the onset of black shale deposition.
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21.
  • Jahangir, Hadi, et al. (författare)
  • The siphonotretide brachiopod Schizambon from the Early Ordovician of South China : ontogeny and affinity
  • 2023
  • Ingår i: Papers in Palaeontology. - : John Wiley & Sons. - 2056-2799 .- 2056-2802. ; 9:4
  • Tidskriftsartikel (refereegranskat)abstract
    • Schizambon is one of the earliest and most distinctive genera in the Order Siphonotretida. However, current knowledge of siphonotretide phylogeny and early evolution requires understanding of their earliest ontogeny. In this study, the new species Schizambon tongziensis from the Tungtzu Formation at Honghuayuan section in Guizhou Province, South China is described; it is also the first record of Schizambon in South China. The new well-preserved specimens shed light on the ontogeny, palaeobiogeographical distribution, phylogeny and early evolution of siphonotretide brachiopods. Characters of metamorphic shells on both valves, outlined by distinct halos, show that Schizambon had a planktotrophic ‘paterinide-type’ larva, typical of many early Palaeozoic brachiopods. Based on the newly obtained data it is inferred that the free-swimming larva of Schizambon settled directly on the ventral side of the body, and this type of ontogeny is probably true for other siphonotretides. The divergence of Schizambon from the main siphonotretide lineage probably happened prior to the Guzhangian Age, well before the occurrence of major biodiversification within the order.
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22.
  • Larsson, Cecilia M (författare)
  • Early Cambrian Problematic Lophotrochozoans and Dilemmas of Scleritome Reconstructions
  • 2012
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • The emergence and radiation of metazoan body plans around the Precambrian/Cambrian boundary, some 500-600 million years ago, seems to be concordant with the appearance and diversification of preservable hard parts. Several Precambrian soft-bodied, multicellular organisms most likely represent stem-group bilaterians, but their fossil record is rather sparse.  In contrast, the Cambrian fossil record is comparably rich – comprising hard part, trace fossil and delicate soft tissue preservation – and most animal phyla that we know of today had evolved by the end of the Cambrian. Consequently, this time represents an important period in the early evolution of metazoan life forms. Most skeletal remnants of invertebrate organisms from this period are preserved in incomplete, disarticulated sclerite assemblages, and the true architecture of the original skeletal structure, the scleritome, may therefore be hard to discern. Many scleritomous taxa have been suggested to be members of the lophotrochozoan clade, while their exact position within this group remains unclear. Such taxa are often referred to as Problematica. This thesis deals with some problematic scleritomous early Cambrian lophotrochozoans, and as such also addresses the dilemmas of scleritome reconstructions. In the first part, completely disarticulated calcareous sclerites from the lower Cambrian of North Greenland are described as Trachyplax arctica. Hypothetical scleritome reconstruction alternatives and comparisons to other scleritome-bearing taxa are discussed, but the lack of articulated material obscures any satisfactory conclusions regarding phylogenetic affinities and the original morphology of the organism. The other part of the thesis focuses on some minute, organophosphatic scleritomous metazoans, tommotiids, found in lower Cambrian limestone successions in South Australia – Paterimitra pyramidalis and Kulparina rostrata – their scleritome architecture and their phylogenetic relationship with paterinid brachiopods. The oldest brachiopod from South Australia, Askepasma saproconcha, and the slightly younger Askepasma toddense are also described and discussed. Based on articulated specimens, recently described partial scleritomes of the tommotiid Eccentrotheca helenia and similarities in shell ultrastructure with both Eccentrotheca and Askepasma, Paterimitra is interpreted as a stem-group brachiopod and reconstructed as a bilaterally symmetrical, sessile, filter feeder with a tubular/conical scleritome. The morphological similarities with Paterimitra point in the same direction for the slightly older Kulparina.
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23.
  • Liang, Yue, et al. (författare)
  • Evolutionary contingency in lingulid brachiopods across mass extinctions
  • 2023
  • Ingår i: Current Biology. - : Elsevier BV. - 0960-9822 .- 1879-0445. ; 33:8, s. 1565-1572.e3
  • Tidskriftsartikel (refereegranskat)abstract
    • Morphology usually serves as an effective proxy for functional ecology,1,2,3,4,5 and evaluating morphological, anatomical, and ecological changes permits a deeper understanding of the nature of diversification and macroevolution.5,6,7,8,9,10,11,12 Lingulid (order Lingulida) brachiopods are both diverse and abundant during the early Palaeozoic but decrease in diversity over time, with only a few genera of linguloids and discinoids present in modern marine ecosystems, resulting in them frequently being referred to as “living fossils.”13,14,15 The dynamics that drove this decline remain uncertain, and it has not been determined if there is an associated decline in morphological and ecological diversity. Here, we apply geometric morphometrics to reconstruct global morphospace occupation for lingulid brachiopods through the Phanerozoic, with results showing that maximum morphospace occupation was reached by the Early Ordovician. At this time of peak diversity, linguloids with a sub-rectangular shell shape already possessed several evolutionary features, such as the rearrangement of mantle canals and reduction of the pseudointerarea, common to all modern infaunal forms. The end Ordovician mass extinction has a differential effect on linguloids, disproportionally wiping out those forms with a rounded shell shape, while forms with sub-rectangular shells survived both the end Ordovician and the Permian-Triassic mass extinctions, leaving a fauna predominantly composed of infaunal forms. For discinoids, both morphospace occupation and epibenthic life strategies remain consistent through the Phanerozoic. Morphospace occupation over time, when considered using anatomical and ecological analyses, suggests that the limited morphological and ecological diversity of modern lingulid brachiopods reflects evolutionary contingency rather than deterministic processes.
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24.
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25.
  • Popov, Leonid E., et al. (författare)
  • Biogeography of Ordovician linguliform and craniiform brachiopods
  • 2013
  • Ingår i: Early Palaeozoic Biogeography and Palaeogeography. - : Geological Society of London. - 9781862393738 ; , s. 117-126
  • Bokkapitel (refereegranskat)abstract
    • The biogeographical patterns shown by Ordovician linguliform and craniiform brachiopods are greatly influenced by their dominance in low-diversity associations in marginal environments. This is particularly evident in the Early Ordovician, when linguliform-dominated dysaerobic assemblages are widely distributed along the deep shelves of Gondwana, the Kazakhstanian terranes and in Baltica. By the Darriwilian, micromorphic linguliforms are characteristic components of the pantropical climatic-controlled faunas of Laurentia, Cuyania and Kazakhstanian terranes, which – in spite of separation by extensive oceans – retain a distinct similarity. Analysis of craniiform biogeographical distribution is impeded significantly by the poor state of craniide taxonomy and lack of reliable data from most regions. However, in general their biogeographical dispersion is similar to other groups of the Palaeozoic Evolutionary Fauna. Unlike the linguliforms, which are important members of the Cambrian Evolutionary Fauna, there is no convincing Cambrian craniiform record; they may have evolved and dispersed from Gondwana and associated microcontinents and island arcs. The earliest well-established record is from the late Tremadocian of temperate to high-latitude peri-Gondwana. During most of the Ordovician, they have a peri-Iapetus distribution. They are very rare or absent in tropical Gondwana, South China and Kazakhstanian terranes and are not yet documented from Siberia. The trimerellides probably evolved in tropical peri-Gondwanan island arc settings. Their dispersion and major features of biogeography mirror those of atrypides.
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26.
  • Popov, Leonid E., et al. (författare)
  • Cambrian (Furongian) rhynchonelliform brachiopods from the Eastern Alborz Mountains, Iran
  • 2013
  • Ingår i: Bulletin of Geosciences. - : Czech Geological Survey. - 1214-1119 .- 1802-8225. ; 88:3, s. 525-538
  • Tidskriftsartikel (refereegranskat)abstract
    • The Cambrian (Furongian) shallow water carbonates in the Mila Formation in the Tuyeh-Darvar area (eastern Alborz, northern Iran) contain numerous shell beds, entirely composed of disarticulated valves of the billingsellide brachiopods Billingsella? fortis sp. nov. and Hyrcanostrophia tuyehensis gen. et sp. nov. Higher up in the Mila Formation, the shallow water carbonates are replaced by nodular limestones, deposited in an open marine environment, containing Palaeostrophia tecta Nikitin & Popov, 1983 and the early polytoechioid Darvaretoechia prisca gen. et sp. nov. These two different brachiopod assemblages are assigned to the oligotaxic Billingsella and Palaeostrophia associations, respectively. These associations are considered to represent precursors to the brachiopod-dominated benthic assemblages of the Palaeozoic Evolutionary Fauna. The new brachiopod faunas from the Alborz Terrane are closely similar to contemporaneous Furongian faunas from the Australasian sector of Gondwana, in particular, to those from South China and the Kazakhstanian terranes.
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27.
  • Popov, L. E., et al. (författare)
  • Earliest ontogeny of Early Palaeozoic Craniiformea : compelling evidence for lecithotrophy
  • 2012
  • Ingår i: Lethaia. - : Scandinavian University Press / Universitetsforlaget AS. - 0024-1164 .- 1502-3931. ; 45:4, s. 566-573
  • Tidskriftsartikel (refereegranskat)abstract
    • The early ontogeny of Palaeozoic Craniiformea (Brachiopoda) remains controversial, with conflicting reports of evidence indicating lecithotrophic versus planktotrophic larval stages. Further compelling evidence for lecithotrophy in Palaeozoic craniiforms is described here. Newly obtained, well-preserved Silurian specimens of craniiforms, including Craniops (Craniopsida), and Lepidocrania? and Orthisocrania (Craniida) from Gotland and the St. Petersburg region, form the basis for this study. The new material demonstrates that the characters of shell structure and shell formation provide evidence of early differentiation of an adult dorsal mantle, and the presence of a distinctive primary layer with a characteristic lath-like pattern indicates that these craniiforms underwent a lecithotrophic larval stage, more or less identical to that of living.
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28.
  • Popov, Leonid E., et al. (författare)
  • Earliest ontogeny of Early Palaeozoic Craniiformea : implications for brachiopod phylogeny
  • 2010
  • Ingår i: Lethaia. - : Scandinavian University Press / Universitetsforlaget AS. - 0024-1164 .- 1502-3931. ; 43:3, s. 323-333
  • Tidskriftsartikel (refereegranskat)abstract
    • Well preserved specimens of the Early Palaeozoic craniiform brachiopods Orthisocrania and Craniops retain clear evidence of a lecithotrophic larval stage, indicating the loss of planktotrophy early in their phylogeny. The size of the earliest mineralized dorsal shell was <100 mu m across, and the well preserved shell structure in these fossil craniiforms allows their earliest ontogeny to be compared directly with that of living Novocrania, in which the first mineralized dorsal shell (metamorphic shell) is secreted only after settlement of the lecithotrophic larvae. Immediately outside this earliest shell (early post-metamorphic or brephic shell) and in the rest of the dorsal valve the primary layer in both fossil and living craniiforms has characteristic radially arranged laths, which are invariably lacking in the earliest dorsal shell. The ventral valve of the fossil specimens commonly preserves traces of an early attachment scar (cicatrix), which is equal in size to the dorsal metamorphic shell, and the brephic post-metamorphic ventral valve also has a primary shell with radially arranged laths. However, a primary shell with radial laths is completely lacking in the ventral valve of living Novocrania, indicating that heterochrony may have been involved in the origin of the encrusting mode of life in living craniids; the entire ventral valve of Recent craniids (with the possible exception of Neoancistrocrania) may correspond to the earliest attachment scar of some fossil taxa such as Orthisocrania. It is also probable that the unique absence of an inner mantle lobe as well as the absence of lobate cells in Novocrania could be the result of heterochronic changes. The dorsal valve of both fossil and living craniiforms has a marked outer growth ring, around 500 mu m across, marking the transition to the adult, and a significant change in regime of shell secretion. The earliest craniiform attachment is considered to be homologous to the unique attachment structures described recently in polytoechioids (e.g. Antigonambonites) and other members of the strophomenate clade. However, unlike the craniiforms, polytoechioids and strophomenates all have planktotrophic larvae, and planktotrophy is most probably a plesiomorphic character for all Brachiopoda.
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29.
  • Popov, Leonid E., et al. (författare)
  • Earliest ontogeny of Middle Ordovician rhynchonelliform brachiopods (Clitambonitoidea and Polytoechioidea) : Implications for brachiopod phylogeny
  • 2007
  • Ingår i: Lethaia. - : Scandinavian University Press / Universitetsforlaget AS. - 0024-1164 .- 1502-3931. ; 40:1, s. 85-96
  • Tidskriftsartikel (refereegranskat)abstract
    • New data on the earliest ontogeny of Mid-Ordovician Baltoscandian clitambonitoid (Apomatella, Neumania and Oslogonites) and polytoechioid (Antigonambonites and Raunites) brachiopods reveal significant differences in the life history of the taxa belonging to these two superfamilies. The Polytoechioidea and probably other members of the Billingsellida had planktotrophic larvae, in which the dorsal and ventral mantle lobes formed separately and without reversion. The 'pedicle sheath' in Antigonambonites is secreted by a section of modified ventral mantle and thus this 'pedicle' is not homologous within the pedicle of rhynchonellate brachiopods. It is likely that polytoechioids and other members of the strophomenate clade had the same type of ontogeny and mode of attachment. In contrast, the ontogeny and mode of attachment of clitambonitoids are similar to that of recent rhynchonellates: their mantle lobes and both valves formed simultaneously, and the pedicle most likely formed from the larval pedicle lobe. Evidence for the lecithotrophic nature of clitambonitoid larva is discussed. This confirms that the Clitambonitoidea, unlike the Polytoechioidea, represents an ingroup within the Rhynchonellata.
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30.
  • Popov, Leonid E., et al. (författare)
  • Early ontogeny and soft tissue preservation in siphonotretide brachiopods : New data from the Cambrian-Ordovician of Iran
  • 2009
  • Ingår i: Gondwana Research. - : Elsevier BV. - 1342-937X .- 1878-0571. ; 16:1, s. 151-161
  • Tidskriftsartikel (refereegranskat)abstract
    • New Late Cambrian (Furongian) to Early Ordovician (Tremadocian) assemblages of micromorphic organo-phosphatic (linguliformean) brachiopods from Iran are characterised by the presence of exceptionally well preserved material of the Order Siphonotretida, a small, phylogenetically important group with a very poorly documented Cambrian history. Unlike other known Cambrian siphonotretides, which generally lack true spines, the new Iranian taxa preserve the constant presence of hollow spines from as early as the mid Late Cambrian. Early siphonotretide ontogeny remains poorly known, but new data from the Iranian faunas demonstrate that the dorsal larval shell had two pairs of lobes, indicative probably of the presence of larval setal sacs and possibly a rudiment of the embryonic shell. Morphology of the ventral brephic shell. previously unknown in siphonotretides, confirms earlier observations that the adult siphonotretide pedicle attachment was related entirely to the ventral mantle, and it may not be homologous with the pedicle of other lingulates. Phosphatised setae emerging from hollow spines are described for the first time in siphonotretides, most probably representing a retained primitive character. Siphonobolus priscus and Siphonobolus kalshanehensis are established as new species. (C) 2009 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved.
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31.
  • Popov, Leonid E, et al. (författare)
  • Furongian Linguliform Brachiopods from the Alborz Mountains, Iran
  • 2009
  • Ingår i: Memoirs of the Association of Australasian Palaeontologists. - 0810-8889. ; 1:37, s. 103-122
  • Tidskriftsartikel (refereegranskat)abstract
    • Micromorphic linguliform brachiopods are described for the first time from the Furongian part of the Cambrian Mila Formation, eastern Alborz Mountains, Iran. The assemblage is dominated by acrotretides, including Dactylotreta lamellosa n. sp. and Ottenbyella hyrcanica n. sp. as well as species of the new genera Tapuritreta (T. angusta n. sp.) and Sadrocarta (S. delicatus). The siphonotretide Siphonobolus sp. also occurs in abundance, which is unusual for Furongian lingulate faunas. The newly discovered assemblage shows little similarity to contemporaneous faunas of Laurentia, Baltica and Kazakhstanian terranes, but S. delicatus is also known from the middle Furongian Series of the Malyi Karatau Range in southern Kazakhstan.
  •  
32.
  • Popov, Leonid E, et al. (författare)
  • Glendonite occurrences in the Tremadocian of Baltica : first Early Palaeozoic evidence of massive ikaite precipitation at temperate latitude
  • 2019
  • Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 9
  • Tidskriftsartikel (refereegranskat)abstract
    • The Tremadocian (Early Ordovician) is currently considered a time span of greenhouse conditions with tropical water surface temperature estimates, interpolated from oxygen isotopes, approaching 40 °C. In the mid-latitude Baltoscandian Basin, conodonts displaying low δ18O values, which suggest high temperatures (>40 °C) in the water column, are in contrast with the discovery of contemporaneous glendonite clusters, a pseudomorph of ikaite (CaCO3·6H2O) traditionally considered as indicator of near-freezing bottom-water conditions. The massive precipitation of this temperature sensitive mineral is associated with transgressive conditions and high organic productivity. As a result, the lower Tremadocian sediments of Baltoscandia apparently contain both "greenhouse" pelagic signals and near-freezing substrate indicators. This paradox points to other primary controlling mechanisms for ikaite precipitation in kerogenous substrates, such as carbonate alkalinity, pH and Mg/Ca ratios, as recently constrained by laboratory experiments. Preservation of "hot" conodonts embedded in kerogenous shales rich in δ18O-depleted glendonites suggests both the onset of sharp thermal stratification patterns in a semi-closed basin and the assumed influence of isotopically depleted freshwater yielded by fluvial systems.
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33.
  • Popov, Leonid E., et al. (författare)
  • Gondwanan faunal signatures from Early Palaeozoic terranes of Kazakhstan and Central Asia : evidence and tectonic implications
  • 2009
  • Ingår i: Geological Society, London, Special Publications. ; 325:1, s. 23-64
  • Tidskriftsartikel (refereegranskat)abstract
    • Two separate tectonic blocks in the southwestern segment of the Kazakhstanian orogen, the Chu-Ili terrane and the Karatau-Naryn terrane (with particular attention to Malyi Karatau), are selected to illustrate their geological history and major biogeographical signatures from the Cambrian to the early Silurian. Mid- to Late Ordovician brachiopod and trilobite faunas of Chu-Ili show increased endemicity of shallow shelf assemblages, whereas distinct links to equatorial ( east') peri-Gondwanan are more evident in trilobite assemblages of the outer shelf. In the Late Ordovician, strong biogeographical affinities to equatorial Gondwanan faunas became firmly established and they are also traceable into the Silurian. Early Cambrian faunas of Malyi Karatau show remarkable similarity to those of South China. From the Middle Cambrian this region evolved as an isolated carbonate seamount, but until the Early Ordovician links to South China faunas were still evident. Benthic faunas from both regions show weak links to contemporaneous faunas of Baltica and little in common with Cambrian and Ordovician faunas of the Siberian craton. This suggests their location in low southern latitudes, in relative proximity to East Gondwana, which places some constraints on plate-tectonic reconstructions in relation to the southern cluster of Kazakhstanian terranes, including Karatau-Naryn, North Tien Shan and Chu-Ili.
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34.
  • Popov, Leonid E., et al. (författare)
  • Himalayan Cambrian brachiopods
  • 2015
  • Ingår i: Papers in Palaeontology. - : Wiley. - 2056-2799 .- 2056-2802. ; 1:4, s. 345-399
  • Tidskriftsartikel (refereegranskat)abstract
    • A synoptic analysis of previously published material and new finds reveals that Himalayan Cambrian brachiopods can be referred to 18 genera, of which 17 are considered herein. These contain 20 taxa assigned to species, of which five are new: Eohadrotreta haydeni, Aphelotreta khemangarensis, Hadrotreta timchristiorum, Prototreta? sumnaensis and Amictocracens? brocki. Well-preserved topotype material from the classic Parahio Valley section is described for three species that have not previously been illustrated photographically. A biostratigraphical scheme based on Cambrian brachiopod occurrence is integrated with that recently proposed for trilobites. Regional correlations based on shared taxa within and across Himalayan lithotectonic belts demonstrate that erosion of Cambrian rocks in the Kurgiakh orogeny in the Parahio Valley removed little of the Parahio Formation and that all of the fossil-bearing lithotectonic zones share similar late early Cambrian brachiopods, suggesting regional faunal continuity at the time. Palaeobiogeographical analysis of the Cambrian brachiopod faunas from the Himalaya shows that they occupied a marginal position of the Australasian segment of Gondwana.
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35.
  • Popov, Leonid E., et al. (författare)
  • Silurian (Aeronian) rhynchonelliform brachiopods of Shabdjereh, south-west Central Iran and their significance for early spiriferide evolution
  • 2021
  • Ingår i: Journal of Systematic Palaeontology. - : Taylor & Francis. - 1477-2019 .- 1478-0941. ; 19:3, s. 191-219
  • Tidskriftsartikel (refereegranskat)abstract
    • The Silurian (Aeronian) post-extinction recovery brachiopod fauna of Iran and Afghanistan is characterized by a proliferation of the Stegocornu Brachiopod Association, which includes prominent endemic rhynchonellide and spiriferide components. A local variety of that association, recently recovered from the Shabdjereh Formation of Kerman Province, East-Central Iran, contains eight brachiopod species, including the rhynchonellide Kermanirhyncha granulata gen. et sp. nov., and the spiriferides Levanispirifer alatus gen. et sp. nov. and Mictospirifer obtusus sp. nov. A new phylogenetic analysis of the earliest Late Ordovician to Aeronian spiriferides, within the general context of the Ordovician radiation of rhynchonelliform brachiopods with calcified brachial supports, reveals the following two major centres of biodiversification and dispersal: (1) the Laurentian palaeocontinent, which is the likely place of origin and initial diversification of the atrypide suborders Lissatrypidina and Anazygidina; and (2) the assemblage of Kazakh island arcs and microplates (known also as Kazakh Archipelago), which was the centre of origin and initial dispersal of the atrypid suborder Atrypidina and the order Spiriferida. South China represents a major refuge, where spiriferides survived the terminal Ordovician extinction and from where they dispersed towards adjacent parts of Gondwana including the Iranian terranes. The latter areas were an important secondary centre of spiriferide biodiversification during the Aeronian Age.
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36.
  • Skovsted, Christian B., et al. (författare)
  • The scleritome of Eccentrotheca from the Lower Cambrian of South Australia : Lophophorate affinities and implications for tommotiid phylogeny
  • 2008
  • Ingår i: Geology. - 0091-7613 .- 1943-2682. ; 36:2, s. 171-174
  • Tidskriftsartikel (refereegranskat)abstract
    • The first partially articulated scleritome of a tommotiid, Eccentrotheca sp., is described from the Lower Cambrian of South Australia. The Eccentrotheca scleritome consists of individual sclerites; fused in a spiral arrangement, forming a tapering tube-shaped skeleton with an inclined apical aperture and a circular to subcircular cross section. Traditionally, tommotiid sclerites have been assumed to form a dorsal armor of imbricating phosphatic plates in slug-like bilaterians, analogous to the calcareous sclerites of halkieriids. The structure of the Eceentrotheca scleritome is here reinterpreted as a tube composed of independent, irregularly shaped sclerites growing by basal-marginal accretion that were successively fused to form a rigid, protective tubular structure. The asymmetrical shape and sometimes acute inclination of the apical aperture suggests that the apical part of the scleritome was cemented to a hard surface via a basal disc, from which it projected vertically. Rather than being a vagrant member of the benthos, Eccentrotheca most likely represented a sessile, vermiform filter feeder. The new data suggest that the affinities of Eccentrotheca, and possibly some other problematic tommotiids, lie with the lophophorates (i.e., the phoronids and brachiopods), a clade that also possesses a phosphatic shell chemistry and a sessile life habit.
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37.
  • Skovsted, Christian B., et al. (författare)
  • The scleritome of Paterimitra : an Early Cambrian stem group brachiopod from South Australia
  • 2009
  • Ingår i: Proceedings of the Royal Society of London. Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 276:1662, s. 1651-1656
  • Tidskriftsartikel (refereegranskat)abstract
    • Early Cambrian tommotiids are problematic fossil metazoans with external organophosphatic sclerites that have been considered to be basal members of the lophophorate stem group. Tommotiids are almost exclusively known from isolated or rarely fused individual sclerites, which made previous reconstructions of the actual organism highly conjectural. However, the recent discovery of the first articulated specimens of the tommotiid Eccentrotheca revealed a tubular sclerite arrangement (scleritome) that limited the possible life habit to sessile filter feeding and thus further supported a lophophorate affinity. Here, we report the first articulated specimens of a second tommotiid taxon, Paterimitra from the Early Cambrian of the Arrowie Basin, South Australia. Articulated specimens of Paterimitra are composed of two bilaterally symmetrical sclerite types and an unresolved number of small, asymmetrical and irregular crescent-shaped sclerites that attached to the anterior margin of the symmetrical sclerites. Together, the sclerites form an open cone in which the symmetrical sclerites are joined together and form a small posterior opening near the base of the scleritome, while the irregular crescent-shaped sclerites defined a broad anterior opening. The coniform scleritome of Paterimitra is interpreted to have attached to hard substrates via a pedicle that emerged through the small posterior opening ( sometimes forming a tube) and was probably a sessile filter feeder. The scleritome of Paterimitra can be derived from the tubular scleritome of Eccentrotheca by modification of basal sclerites and reduction in tube height, and probably represents a more derived member of the brachiopod stem group with the paired symmetrical sclerites possibly homologous to brachiopod valves.
  •  
38.
  • Skovsted, Christian, 1974-, et al. (författare)
  • Taxonomy, morphology, shell structure and early ontogeny of Pelmanotreta nom. nov. from the lower Cambrian of Siberia
  • 2015
  • Ingår i: GFF. - : Informa UK Limited. - 1103-5897 .- 2000-0863. ; 137:1, s. 1-8
  • Tidskriftsartikel (refereegranskat)abstract
    • The new generic name Pelmanotreta is proposed under the provisions of the International Code of Zoological Nomenclature (ICZN) to replace Cryptotreta Pelman, 1977 (Brachiopoda), a junior homonym of Cryptotreta Blanc & Foote, 1961 (Arthropoda). This poorly known brachiopod genus and its type and only species, Pelmanotreta neguertchenensis (Pelman, 1977), from the early Cambrian of Siberia is redescribed. The family-level taxonomy of Pelmanotreta and other “cryptotretid” brachiopods is uncertain. In Pelmanotreta, dorsal valves vastly outnumber ventral valves in all collections but new specimens of the poorly known ventral valve reveal a possibly septate and poorly mineralized apical region. A prismatic hexagonal shell structure comparable to that of Salanygolina is described. P. neguertchenensis preserves the earliest known record of a larval shell in brachiopods.
  •  
39.
  • Tolmacheva, Tatiana, et al. (författare)
  • Conodont biostratigraphy and faunal assemblages in radiolarian ribbon-banded cherts of the Burubaital Formation, West Balkhash Region, Kazakhstan
  • 2004
  • Ingår i: Geological Magazine. - 0016-7568 .- 1469-5081. ; 141:6, s. 699-715
  • Tidskriftsartikel (refereegranskat)abstract
    • Biostratigraphical study of the early to mid-Ordovician conodont fauna from ribbon-banded radiolarian cherts of the middle Burubaital Formation in Central Kazakhstan reveals an almost complete succession of conodont biozones from the late Tremadocian to the early Darriwilian. During this interval, biosiliceous sediments were deposited in basinal environments, inhabited by lingulate brachiopods, sponges, pterobranchs and caryocaridids in conditions of high fertility and primary productivity of surface water. The community structure of taxonomically diverse conodont assemblages typifying open oceanic environments is not significantly different from that of epicratonic basins of the North Atlantic conodont province. The regional increase of oxygenated bottom waters at the base of the Oepikodus evae Biozone is possibly related to considerable changes in palaeo-oceanographical circulation patterns. The finds of three natural clusters of Prioniodus oepiki (McTavish) enable us to propose an emended diagnosis of this species.
  •  
40.
  • Zhang, Zhifei, et al. (författare)
  • A sclerite-bearing stem group entoproct from the early Cambrian and its implications
  • 2013
  • Ingår i: Scientific Reports. - London : Nature Publishing Group. - 2045-2322. ; 3, s. 1-7
  • Tidskriftsartikel (refereegranskat)abstract
    • The Lophotrochozoa includes disparate tentacle-bearing sessile protostome animals, which apparently appeared in the Cambrian explosion, but lack an uncontested fossil record. Here we describe abundant well preserved material of Cotyledion tylodes Luo et Hu, 1999, from the Cambrian (Series 2) Chengjiang deposits, reinterpreted here as a stem-group entoproct. The entoproct affinity is supported by the sessile body plan and interior soft anatomy. The body consists of an upper calyx and a lower elongate stalk with a distal holdfast. The soft anatomy includes a U-shaped gut with a mouth and aboral anus ringed by retractable marginal tentacles. Cotyledion differs from extant entoprocts in being larger, and having the calyx and the stalk covered by numerous loosely-spaced external sclerites. The description of entoprocts from the Chengjiang biota traces the ancestry of yet another lophotrochozoan phylum back to the Cambrian radiation, and has important implications for the earliest evolution of lophotrochozoans.
  •  
41.
  • Zhang, Zhiliang, et al. (författare)
  • Earliest ontogeny of early Cambrian acrotretoid brachiopods : first evidence for metamorphosis and its implications
  • 2018
  • Ingår i: BMC Evolutionary Biology. - : Springer Science and Business Media LLC. - 1471-2148. ; 18
  • Tidskriftsartikel (refereegranskat)abstract
    • Our understanding of the ontogeny of Palaeozoic brachiopods has changed significantly during the last two decades. However, the micromorphic acrotretoids have received relatively little attention, resulting in a poor knowledge of their ontogeny, origin and earliest evolution. The uniquely well preserved early Cambrian fossil records in South China provide a great new opportunity to investigate the phylogenetically important ontogeny of the earliest acrotretoid brachiopods, and give new details of the dramatic changes in anatomy of acrotretoid brachiopods during the transition from planktotrophic larvae to filter feeding sedentary juveniles.
  •  
42.
  • Zhang, Zhiliang, et al. (författare)
  • The oldest Cambrian trilobite - brachiopod association in South China
  • 2021
  • Ingår i: Gondwana Research. - : Elsevier. - 1342-937X .- 1878-0571. ; 89, s. 147-167
  • Tidskriftsartikel (refereegranskat)abstract
    • Limestones of the Xihaoping Member of the Dengying Formation in the Xiaoyangba section, South China, yield the oldest known Cambrian brachiopod-trilobite association. In this member, the trilobite Parabadiella cf. huoi co-occurs with the new brachiopod species Eoobolus incipiens sp. nov. The association provides potential for correlation of lower Cambrian successions and gives novel insights into the origin, palaeobiogeographic distribution and early evolution of linguliform brachiopods. Parabadiella occurs in shallow marine clastic and carbonate rocks in South China, demonstrating a broad distribution for this taxon. The new discovery indicates an early Chiungchussuan age (Parabadiella trilobite Zone, Cambrian Age 3) for the longstanding problematic Xihaoping Member. Furthermore, this earliest Parabadiella-Eoobolus association helps to establish close links with the oldest knowntrilobite-brachiopod assemblage from the upper Micrina etheridgei Zone (Parabadiella huoi trilobite Zone) in Australia. Eoobolus incipiens represents one of the earliest known linguliform brachiopods, with a distinctive mixture of characters shared with both problematic tommotiids, as well as paterinide, lingulide and acrotretide brachiopods, indicating that these features may be plesiomorphic for the Linguliformea. An age-constrained dispersal mode for early lingulate brachiopods is proposed, indicating that the Subphylum Linguliformea may have originated in East Gondwana and South China during Cambrian Age 3, and only subsequently dispersed to other major Cambrian palaeocontinents (e.g. Siberia, Laurentia, Antarctica, Baltica, Avalonia, West Gondwana, North China) during the late stage of the Cambrian evolutionary radiation of animals. (C) 2020 The Author(s). Published by Elsevier B.V. on behalf of International Association for Gondwana Research.
  •  
43.
  • Agbaje, Oluwatoosin B. A., et al. (författare)
  • Biomacromolecules in recent phosphate-shelled brachiopods : identification and characterization of chitin matrix
  • 2021
  • Ingår i: Journal of Materials Science. - : Springer Nature. - 0022-2461 .- 1573-4803. ; 56:36, s. 19884-19898
  • Tidskriftsartikel (refereegranskat)abstract
    • Phosphate-shelled brachiopods differ in filter-feeding lifestyle, with Lingula anatina an active infaunal burrower, and Discinisca tenuis a shallow marine epibenthic animal. The shells of these animals are built of organophosphatic constituents, the organic fibres/sheets reinforced with calcium phosphate to provide a sophisticated ultrastructural robustness. This investigation examined the nature of the organic fibres in order to improve understanding of how living organisms produce hierarchically structured biomaterials. Unlike powdered samples commonly used in previous studies, organic fibres were isolated for the first time and the shell fractions were purified, in order to study the content and nature of the biopolymer fibres. Biochemical methods including Calcofluor staining revealed a chitin matrix. Ultrastructural analysis, thermal gravimetric analysis, and spectroscopic analyses show that the core polysaccharide framework is composed of layers of β-chitin sheets and/or fibrils that are coated with a fibrous organic matrix. There is more chitin matrix in the L. anatina shells (26.6 wt.%) compared to the D. tenuis shells (12.9 wt.%). Taken together, the data show that the chitin matrix contributes to increased skeletal strength, making L. anatina highly adapted for life as an active burrower. In comparison, D. tenuis contains less chitin and lives as attached epibenthos in a shallow marine environment.
  •  
44.
  • Agbaje, Oluwatoosin B. A., et al. (författare)
  • Characterization of organophosphatic brachiopod shells : spectroscopic assessment of collagen matrix and biomineral components
  • 2020
  • Ingår i: RSC Advances. - 2046-2069. ; 10, s. 38456-38467
  • Tidskriftsartikel (refereegranskat)abstract
    • The shells of linguloid brachiopods such as Lingula and Discinisca are inorganic–organic nanocomposites with a mineral phase of calcium phosphate (Ca-phosphate). Collagen, the main extracellular matrix in Ca-phosphatic vertebrate skeletons, has not previously been clearly resolved at the molecular level in organophosphatic brachiopods. Here, modern and recently-alive linguliform brachiopod shells of Lingula and Discinisca have been studied by microRaman spectroscopy, Fourier transform infrared spectroscopy, field emission gun scanning electron microscopy, and thermal gravimetric analysis. For the first time, biomineralized collagen matrix and Ca-phosphate components were simultaneously identified, showing that the collagen matrix is an important moiety in organophosphatic brachiopod shells, in addition to prevalent chitin. Stabilized nanosized apatitic biominerals (up to ∼50 nm) permeate the framework of organic fibrils. There is a ∼2.5-fold higher wt% of carbonate (CO32−) in Lingula versus Discinisca shells. Both microRaman spectroscopy and infrared spectra show transient amorphous Ca-phosphate and octacalcium phosphate components. For the first time, trivalent moieties at ∼1660 cm−1 and divalent moieties at ∼1690 cm−1 in the amide I spectral region were identified. These are related to collagen cross-links that are abundant in mineralized tissues, and could be important features in the biostructural and mechanical properties of Ca-phosphate shell biominerals. This work provides a critical new understanding of organophosphatic brachiopod shells, which are some of the earliest examples of biomineralization in still-living animals that appeared in the Cambrian radiation.
  •  
45.
  • Altenburger, Andreas, et al. (författare)
  • Metamorphosis in Craniiformea revisited : Novocrania anomala shows delayed development of the ventral valve
  • 2013
  • Ingår i: Zoomorphology. - : Springer Science and Business Media LLC. - 0720-213X .- 1432-234X. ; 132:4, s. 379-387
  • Tidskriftsartikel (refereegranskat)abstract
    • We revisited the brachiopod fold hypothesis and investigated metamorphosis in the craniiform brachiopod Novocrania anomala. Larval development is lecithotrophic and the dorsal (brachial) valve is secreted by dorsal epithelia. We found that the juvenile ventral valve, which consists only of a thin layer that was previously described as periostracal, is not a valve and is not secreted by the same epithelia as the dorsal valve. It is secreted by the attachment area of the larva at the posterior-most tip of the posterior larval lobe. The same attachment area is used by larvae of rhynchonelliform brachiopods during metamorphosis to cement their pedicle to the substrate. N. anomala is therefore not initially attached by a valve but by material corresponding to pedicle cuticle. This is different to previous descriptions, which had led to speculations about a folding event in the evolution of Brachiopoda. We show that the “brachiopod fold hypothesis,” which argues that brachiopods are transversely “folded” across the ontogenetic anterior–posterior axis, should be rejected at least with respect to the craniiforms. The data now suggest that the Craniiformea may be a derived group within the Rhynchonelliformea. This interpretation suggests that the last common ancestor of the Craniiformea has lost the pedicle and the ventral valve in early juvenile development. Characters that have previously been considered to be shared between the Craniiformea and the Linguliformea (clade Inarticulata), such as a through-gut and missing hinge articulation, may thus be secondarily derived characters of the Craniiformea within the Rhynchonelliformea.
  •  
46.
  •  
47.
  • Balthasar, Uwe, et al. (författare)
  • Homologous skeletal secretion in tommotiids and brachiopods
  • 2009
  • Ingår i: Geology. - 0091-7613 .- 1943-2682. ; 37:12, s. 1143-1146
  • Tidskriftsartikel (refereegranskat)abstract
    • Tommotiids are distinctive components of the early Cambrian small shelly fauna, almost invariably represented by isolated phosphatic sclerites derived from a multielement protective cover (scleritome). The unusual range of tommotiid sclerite morphologies and unknown construction of the scleritome have severely hampered our understanding of their phylogenetic affinities. However, recent description of rare, articulated scleritome material belonging to the tommotiid genera Eccentrotheca and Paterimitra support the hypothesis that some tommotiids fall within the stem group of the lophophorate phyla Phoronida and Brachiopoda and that at least some tommotiid sclerites are homologous precursors of the shells of organophosphatic brachiopods. Here we show that the shell microstructure of Eccentrotheca and Paterimitra share substantial similarities with paterinid brachiopods. While paterinids possess an overall brachiopod morphology, their microstructure appears more similar to Eccentrotheca and Paterimitra than to nonpaterinate lingulids. These findings strongly support the existence of a brachiopod total group that is solidly rooted within tommotiids, and identify the organophosphatic skeletal composition as plesiomorphic with calcareous shells as derived. The microstructural changes of the proposed tommotiid-brachiopod transition probably reflect an adaptation to fluctuating food and phosphorous intake that came with the switch to a sessile life style at the base of the tommotiid clade.
  •  
48.
  •  
49.
  • Brock, Glenn A., et al. (författare)
  • Early Ordovician brachiopods from the Emanuel Formation, Canning Basin, Western Australia
  • 2004
  • Ingår i: Memoirs of the Association of Australasian Palaeontologists. - : Association of Australasian Palaeontologists. - 0810-8889. ; :30, s. 113-132
  • Tidskriftsartikel (refereegranskat)abstract
    • The lingulate brachiopods from the type section of the Emanuel Fonnation, Canning Basin, Western Australia are described. The fauna consists on new obolid taxa, Libecoviella divaricata n. sp., Wahwahlingula? emanuelensis n. sp., and Zhanatellidae n. gen? A, and two acrotretoids, Semitreta lauriei n. sp., and Ottenbyella shidertensis (Popov & Holmer, 1994). Contemporaneous trilobite and conodont faunas indicate a late Lancefieldian (La3) to mid Bendigonian (Be2) (=earliest Arenigian) age for the Emanuel Fonnation. The lingulate fauna is largely endemic at the species level, with minor faunal links to Kazakhstan and Bohemia.
  •  
50.
  • Butler, Aodhán D., 1986- (författare)
  • Decoding the fossil record of early lophophorates : Systematics and phylogeny of problematic Cambrian Lophotrochozoa
  • 2015
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • The evolutionary origins of animal phyla are intimately linked with the Cambrian explosion, a period of radical ecological and evolutionary innovation that begins approximately 540 Mya and continues for some 20 million years, during which most major animal groups appear. Lophotrochozoa, a major group of protostome animals that includes molluscs, annelids and brachiopods, represent a significant component of the oldest known fossil records of biomineralised animals, as disclosed by the enigmatic ‘small shelly fossil’ faunas of the early Cambrian. Determining the affinities of these scleritome taxa is highly informative for examining Cambrian evolutionary patterns, since many are supposed stem-group Lophotrochozoa. The main focus of this thesis pertained to the stem-group of the Brachiopoda, a highly diverse and important clade of suspension feeding animals in the Palaeozoic era, which are still extant but with only with a fraction of past diversity. Major findings include adding support for tommotiid affinity as stem-group lophophorates. Determining morphological character homologies vital to reconstructing the brachiopod stem-group was achieved by comparing Cambrian Lagerstätten with the widespread biomineralised record of Cambrian stem-brachiopods and small shelly fossils. Polarising character changes associated with the putative transition from scleritome organisms to crown-group brachiopods was furthered by the description of an enigmatic agglutinated tubular lophophorate Yuganotheca elegans from the Chengjiang Lagerstätte, China, which possesses an unusual combination of phoronid, brachiopod and tommotiid characters. These efforts were furthered by the use of X-ray tomographic techniques that revealed novel anatomical features, including exceptionally preserved setae in the tommotiid Micrina. The evidence for a common origin of columnar brachiopod shell structures in the tommotiids is suggested and critically examined. Enigmatic and problematic early and middle Cambrian lophotrochozoans are newly described or re-described in light of new evidence, namely: the stem-brachiopod Mickwitzia occidens Walcott from the Indian Springs Lagerstätte, Nevada; a putative stem-group entoproct Cotyledion tylodes Luo and Hu from Chengjiang, China; a new enigmatic family of rhynchonelliform brachiopods exemplified by the newly described Tomteluva perturbata from the Stephen Formation, Canada; and the tommotiid Micrina etheridgei (Tate) from the Flinders Ranges, South Australia. Cladistic analyses of fossil morphological data supports a monophyletic Brachiopoda.
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