| 1. |
- Streng, Michael, 1971-, et al.
(författare)
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Columnar shell structures in early linguloid brachiopods : new data from the Middle Cambrian of Sweden
- 2008
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Ingår i: Earth and Environmental Science Transactions of the Royal Society of Edinburgh. - 1755-6910. ; 98:Part 3-4, s. 221-232
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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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| 2. |
- Holmer, Lars E., et al.
(författare)
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Lower Ordovician (Tremadocian) lingulate brachiopods from the House and Fillmore formations, Ibex Area, western Utah, USA
- 2005
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Ingår i: Journal of Paleontology. - 0022-3360 .- 1937-2337. ; 79:5, s. 884-906
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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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| 3. |
- Popov, Leonid E., et al.
(författare)
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Earliest ontogeny of Middle Ordovician rhynchonelliform brachiopods (Clitambonitoidea and Polytoechioidea) : Implications for brachiopod phylogeny
- 2007
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Ingår i: Lethaia. - : Scandinavian University Press / Universitetsforlaget AS. - 0024-1164 .- 1502-3931. ; 40:1, s. 85-96
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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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| 4. |
- Popov, Leonid E., et al.
(författare)
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Early ontogeny and soft tissue preservation in siphonotretide brachiopods : New data from the Cambrian-Ordovician of Iran
- 2009
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Ingår i: Gondwana Research. - : Elsevier BV. - 1342-937X .- 1878-0571. ; 16:1, s. 151-161
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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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| 5. |
- Popov, Leonid E, et al.
(författare)
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Furongian Linguliform Brachiopods from the Alborz Mountains, Iran
- 2009
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Ingår i: Memoirs of the Association of Australasian Palaeontologists. - 0810-8889. ; 1:37, s. 103-122
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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.
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| 6. |
- Popov, Leonid E., et al.
(författare)
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Gondwanan faunal signatures from Early Palaeozoic terranes of Kazakhstan and Central Asia : evidence and tectonic implications
- 2009
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Ingår i: Geological Society, London, Special Publications. ; 325:1, s. 23-64
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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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| 7. |
- Bassett, Michael G., et al.
(författare)
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Pedicle preservation in a Silurian rhynchonelliformean brachiopod from Herefordshire, England : soft-tissue or an artefact of interpretation?
- 2008
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Ingår i: Earth and Environmental Science Transactions of the Royal Society of Edinburgh. - 1755-6910. ; 98:3-4, s. 303-308
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Tidskriftsartikel (refereegranskat)abstract
- The interpretation of pedicle soft tissue preservation in a unique brachiopodspecimen of Wenlock (Silurian) age from Herefordshire, western England, is re-assessed. Bethia serraticulma, assigned originally to the Orthida, is more probably a member of the Strophomenida (Plectambonitoidea). The supposed pedicle structure is more plausibly a weakly mineralised pedicle sheath, which is a common morphological and functional development in the early ontogeny of a number of Palaeozoic brachiopod lineages.
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| 8. |
- Holmer, Lars E., et al.
(författare)
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The enigmatic early cambrian salanygolina : a stem group of rhynchonelliform chileate brachiopods?
- 2009
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Ingår i: Palaeontology. - : Wiley. - 0031-0239 .- 1475-4983. ; 52:1, s. 1-10
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Tidskriftsartikel (refereegranskat)abstract
- New material of the enigmatic brachiopod Salanygolina obliqua Ushatinskaya from the Early Cambrian of Mongolia shows that it has a colleplax- a triangular plate - in the umbonal perforation, which is enlarged by resorption. This structure is otherwise only known from the equally enigmatic Palaeozoic orders Chileida and Dictyonellida (Rhynchonelliformea, Chileata). The colleplax in Salanygolina is here considered to be homologous with that of the chileates. Salanygolina is also provided with a ridge-like pseudodeltidium, which is another chileate feature. Other characters of Salanygolina, like the radial arrangement of adductor muscle scars and postero-medially placed internal oblique muscles are characteristic of chileates, but also found in the paterinates. In contrast, mixoperipheral dorsal valves with low rudimentary interareas are well known in paterinates, but not yet recorded from chileates. Thus, Salanygolina shows a mosaic combination of morphologic characters, known both from the paterinates and chileates, indicating that it may represent a stem group of the rhynchonelliform chileate brachiopods. The laminar phosphatic secondary shell of Salanygolina is composed of closely packed and nearly identical hexagonal prisms, oriented with their long axis normal to the laminae in a honeycomb pattern. The prism walls appear to have originally been composed of organic membranes and might represent precursors of the organic sheaths of calcite fibers that are typical of calcitic shells with a fibrous microstructure.
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| 9. |
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| 10. |
- Popov, Leonid E., et al.
(författare)
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A low diversity shallow water lingulide brachiopod-gastropod association from the Upper Ordovician Almaly Formation of North Kyrgyzstan
- 2007
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Ingår i: Acta Paleontologica Polonica. - 0567-7920. ; 52:1, s. 27-40
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Tidskriftsartikel (refereegranskat)abstract
- A low diversity association made up of the lingulid Tunisiglossa almalensis Popov and Mambetov, sp. nov. and the gas−tropod Ptychonema agyris Ebbestad, sp. nov. is described from the Upper Member of the Almaly Formation at KyrgyzRange, North Tien Shan, Kyrgyzstan/Kazakhstan. The specimens co−occur in dense coquinas, made up of different sizedindividuals, deposited in a shallow water, intertidal, and storm driven depositional environment. The lingulid shells dis−play a completely reduced dorsal pseudointerarea typical of Glossellinae, and the smooth shell lacking fine external gran−ulation, radial or pitted ornament, a small ventral pseudointerarea, and no dorsal median ridge place it in the hithertomonotypic Tunisiglossa known previously only from the Lower Ordovician (Tremadocian) Sanrhar Formation of Libya.It compares with Ectenoglossa sorbulakensis that is widespread in the lower to middle Caradocian Anderken Formationof Chu−Ili Range in southern Kazakhstan. Gastropods of this age have not been reported earlier in Kyrgyzstan; neither canPtychonema be compare with any taxon in the gastropod association earlier described from the contemporary AnderkenFormation in Kazakhstan. Ptychonema is otherwise commonly associated with peri−Gondwana terranes, but the Late Or−dovician dispersal pattern of the genus is unknown. Overall, however, the Upper Ordovician faunas of North Tien Shanshow close similarities to contemporaneous faunas of the Chu−Ili terrane, which have strong biogeographic signatureslinking them to the faunas of South and North China.
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| 11. |
- Popov, Leonid E., et al.
(författare)
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Ordovician (Arenig-Caradoc) Syntrophiidine brachiopods from the East Baltic Region
- 2005
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Ingår i: Palaeontology. - : Wiley. - 0031-0239 .- 1475-4983. ; 48:4, s. 739-761
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Tidskriftsartikel (refereegranskat)abstract
- Syntrophiidine brachiopods are a rare and poorly known component of Ordovician Baltoscandian faunas. They appear in the East Baltic in the Billingenian (lower Arenig) as part of the earliest known benthic assemblages dominated by elements of the Palaeozoic Evolutionary Fauna. These faunal assemblages usually include bryozoans, ostracodes, and the earliest known porambonitoids, strophomenides and endopunctate orthides, such as Idiostrophia and Orthidium, which later became characteristic of the Whiterockian brachiopod assemblages in Laurentia, but by that time had disappeared from Baltica. The superfamily Syntrophioidea reappears in Baltoscandia in the mid Caradoc. In contrast, Porambonitoidea remained the integral part of the Baltoscandian brachiopod associations through the Ordovician. Porambonites, herein redefined on the basis of restudy of the type species P. intermedius, includes only smooth porambonitoids; taxa with the distinctive ornament of radiating rows of pits first appeared in the group in the mid Arenig. The taxa Eoporambonites gen. nov., Tetralobula peregrina sp. nov., Idiostrophia prima sp. nov. and Idiostrophia tenuicostata sp. nov. are erected.
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