| 1. |
- Balthasar, Uwe
(författare)
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The brachiopod Eoobolus from the Early Cambrian Mural Formation (Canadian Rocky Mountains)
- 2009
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Ingår i: Palaeontologische Zeitschrift. - : Springer Science and Business Media LLC. - 0031-0220 .- 1867-6812. ; 83:3, s. 407-418
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Tidskriftsartikel (refereegranskat)abstract
- The Early Cambrian brachiopod, Eoobolus, is one of the first representatives of the superfamily, Linguloidea, the defining characteristics of which include the classical morphology of oval shells and a pedicle that emerges from between the two valves. The material described here from the Mural Formation (Jasper National Park, Canadian Rocky Mountains) provides well-preserved muscle scars and larval shells that allow a discussion of the muscle system and the larval morphology of Eoobolus. The dorsal larval shell exhibits a morphology similar to other Cambrian linguloids, but also to paterinids, Mickwitzia muralensis, and some rhynchonelliforms. This suggests that there was a lesser degree of disparity among brachiopod larvae in the Cambrian than there is today. The muscle system of Eoobolus is similar to other linguloids, but differs from that of Recent lingulids and discinids by having one or two more pairs of oblique muscles. New data on the distribution of features characteristic of the family Eoobolidae question the validity of this family.
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| 2. |
- Cope, John C. W., et al.
(författare)
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Tergomyan molluscs from the Early Ordovician of the Llangynog Inlier, South Wales, UK
- 2024
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Ingår i: Palaeontologische Zeitschrift. - : Springer. - 0031-0220 .- 1867-6812. ; 98:1, s. 17-28
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Tidskriftsartikel (refereegranskat)abstract
- A low abundance but diverse fauna of tergomyan molluscs is described from the Llangynog Inlier, Carmarthenshire, South Wales. The specimens originate from a single quarry exposing shallow-water siltstone and mudstone beds of the Early Arenig (early Floian) Bolahaul Member of the Ogof Hen Formation. The fauna includes Proplina areniga sp. nov., Proplina? obtusa sp. nov., Celtopileus calvapex gen. et sp. nov. with preserved muscle scars, Costulaconus mirificus gen. et sp. nov., and Hypseloconus? sp. Comparable tryblidiid taxa are mainly found in the Lower Ordovician of Midwestern USA among species of Proplina Kobayashi, 1933 and Gasconadeoconus Stinchcomb, 1986. The tentative assignment of the predominantly late Cambrian Hypseloconus is symptomatic of the many uncertainties regarding the phylogeny of the tryblidiids. The diverse assemblage of organisms preserved at the single locality represents one of the most remarkable faunas of this age worldwide.
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| 3. |
- Duda, Jan-Peter, et al.
(författare)
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Molecular fossils within bitumens and kerogens from the ~ 1 Ga Lakhanda Lagerstätte (Siberia, Russia) and their significance for understanding early eukaryote evolution
- 2021
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Ingår i: Palaeontologische Zeitschrift. - : Springer Nature. - 0031-0220 .- 1867-6812. ; 95, s. 577-592
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Tidskriftsartikel (refereegranskat)abstract
- The emergence and diversification of eukaryotes during the Proterozoic is one of the most fundamental evolutionary developments in Earth’s history. The ca. 1-billion-year-old Lakhanda Lagerstätte (Siberia, Russia) contains a wealth of eukaryotic body fossils and offers an important glimpse into their ecosystem. Seeking to complement the paleontological record of this remarkable lagerstätte, we here explored information encoded within sedimentary organic matter (total organic carbon = 0.01–1.27 wt.%). Major emphasis was placed on sedimentary hydrocarbons preserved within bitumens and kerogens, including molecular fossils (or organic biomarkers) that are specific to bacteria and eukaryotes (i.e. hopanes and regular steranes, respectively). Programmed pyrolysis and molecular organic geochemistry suggest that the organic matter in the analyzed samples is about peak oil window maturity and thus sufficiently well preserved for detailed molecular fossil studies that include hopanes and steranes. Together with petrographic evidence as well as compositional similarities of the bitumens and corresponding kerogens, the consistency of different independent maturity parameters establishes that sedimentary hydrocarbons are indigenous and syngenetic to the host rock. The possible presence of trace amounts of hopanes and absence of steranes in samples that are sufficiently well preserved to retain both types of compounds evidences an environment dominated by anaerobic bacteria with no or very little inputs by eukaryotes. In concert with the paleontological record of the Lakhanda Lagerstätte, our study adds to the view that eukaryotes were present but not significant in Mesoproterozoic ecosystems.
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| 4. |
- Geyer, Gerd, et al.
(författare)
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A new lowermost middle Cambrian (Series 3, Stage 5) faunule from Saxony (Germany) and its bearing on the tectonostratigraphic history of the Saxothuringian domain
- 2014
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Ingår i: Palaeontologische Zeitschrift. - : Springer Science and Business Media LLC. - 0031-0220 .- 1867-6812. ; 88:3, s. 239-262
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Tidskriftsartikel (refereegranskat)abstract
- The core of borehole 1209/78 west of Doberlug-Kirchhain and south of Herzberg in the Torgau-Doberlug Syncline records an atypical lower part of the Trobitz Formation with thin limestone horizons. These limestone layers include the remains of a low to moderately diverse fauna with the trilobites Protolenus (Hupeolenus) bergstroemi n. sp., Cambrunicornia saxonica n. sp., Ornamentaspis? aff. todraensis Geyer 1990a, Calodiscus? n. sp., the remains of two undetermined olenelloid? and paradoxidid? species, at least two brachiopods (Trematobolus, undetermined acrotretoid), and one hyolith. The fauna clearly suggests a position in the lower Agdzian stage of the West Gondwana chronostratigraphic scheme and correlation with the lowermost to lower Middle Cambrian strata in regions such as the Moroccan Atlas ranges and northern Spain, so the assemblages represent the oldest Middle Cambrian fauna known from the Saxothuringian domain and reconfirm the palaeogeographic position in the Perigondwanan segment. The lithological differences of the fossiliferous cores from those of the typical Trobitz Formation and the recorded high-energy conditions indicate high-frequency sea-level changes suggesting that this part of the succession may be a late stage of the subglobally recognizable eustatic sea-level fluctuations at the traditional Lower-Middle Cambrian boundary interval.
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| 5. |
- Geyer, Gerd, et al.
(författare)
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The Paradoxides puzzle resolved : the appearance of the oldest paradoxidines and its bearing on the Cambrian Series 3 lower boundary
- 2015
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Ingår i: Palaeontologische Zeitschrift. - : Springer Science and Business Media LLC. - 0031-0220 .- 1867-6812. ; 89:3, s. 335-398
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Tidskriftsartikel (refereegranskat)abstract
- The Moroccan Atlas ranges provide sections that help reconstruct the earliest evolution of Paradoxides s.l. A fine-scale analysis of the basal part of the Jbel Wawrmast Formation in the eastern Anti-Atlas and comparisons with other sections in southern Morocco not only shows the abrupt appearance of Acadoparadoxides in nearly monofacial successions, but also illustrates a rapid diversification of the genus. This remarkable evolution of the clade includes material that can be assigned provisionally to the frequently described species Acadoparadoxides mureroensis (Sdzuy, 1958), to A. nobilis (Geyer, 1998) and also to the new species A. pampalius, A. levisettii and A. ovatopyge, of which A. pampalius can be shown to be the oldest described species of Paradoxides s.l. presently known. A fine-scale biostratigraphic and depositional development analysis permits a precise evaluation of suggested correlations within West Gondwana and into other Cambrian continents, and shows that attempts at precise correlations based on Acadoparadoxides species, and particularly A. mureroensis as a key taxon for global correlation, suffer from deficiencies that become obvious. In addition, the often subtle differences between species of the A. mureroensis clade illustrate that a confident identification of these species is only possible for well-preserved and largely undistorted specimens. Thus, many reports of A. mureroensis may be based, in part, on unfavourably preserved specimens of other species. The concept of a fairly variable species and even the idea of a dimorphism seem to have led to problematic identifications. In this context, material from the Taurus Mountains, southern Turkey, identified as A. mureroensis is identified herein as Acadoparadoxides deani n. sp. Paradoxides s.l. species appear to have been quite provincial in their palaeogeographic distribution, and an analysis of early appearing species shows that A. harlani (Green, 1834) was restricted to the Avalonia palaeocontinent, is incorrectly reported from West Gondwana and cannot be used as a basis for lower Series 3 correlation or chronostratigraphy. Finally, the so-called Valdemiedes Event described from the Iberian Chains in Spain obviously is a regional feature based on the abrupt appearance of an early, but not the earliest, Series 3 trilobite assemblage above a barren interval. This "event" appears to be a local stratigraphic artefact and does not reflect regional West Gondwanan or global geological history.
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| 6. |
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| 7. |
- Hoel, Ole A.
(författare)
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Strophomenidae, Leptostrophiidae, Strophodontidae and Shaleriidae (Brachiopoda, Strophomenida) from the Silurian of Gotland, Sweden
- 2011
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Ingår i: Paläontologische Zeitschrift. - : Springer Science and Business Media LLC. - 0031-0220 .- 1867-6812. ; 85:2, s. 201-229
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Tidskriftsartikel (refereegranskat)abstract
- Twelve species of Brachiopods are described from the Silurian of Gotland, six furcitellinines and six "strophodontids." One is new-Strophodonta hoburgensis n. sp. The furcitellinines are moderately common and diverse in the lower part of the succession, but the last species disappears in the middle Hemse beds (similar to middle Ludlow). Three genera are represented: Bellimurina, Pentlandina and Katastrophomena, with the species and subspecies B. wisgoriensis, P. tartana, P. loveni, P. lewisii lewisii, K. penkillensis and K. antiquata scabrosa. Most of the taxa are confined to low energy environments, but P. loveni was evidently specialized for the high energy reef environments of the Hogklint Formation. B. wisgoriensis displays environmentally induced morphological variability in developing strong, frilly growth lamellae in high-energy environments. The "strophodontids," although belonging to three different families, share a common morphology consisting of denticles along the hinge line, a semi-circular outline, unequally to finely costellate ornament and, most importantly, a concavo-convex profile with both valves of the same curvature, enclosing a very small body chamber. Two leptostrophiids are generalists, occurring in both high- and low-energy environments and with long stratigraphical ranges [Mesoleptostrophia filosa; latest Llandovery through the entire Ludlow. Brachyprion (Brachyprion) semiglobosa; latest Llandovery to latest Wenlock]. The third leptostrophiid (Brachyprion (Erinostrophia) walmstedti) is short ranged and occurs in low-energy environments in the latest Llandovery. The species belonging to the Strophodontidae (Strophodonta hoburgensis n. sp.) and Shaleriidae [Shaleria (Janiomya) ornatella and S. (Shaleriella) ezerensis] occur only in high-energy environments and have a short range within the late Ludlow.
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| 8. |
- Holmer, Lars E., et al.
(författare)
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The first occurrence of a lingulid brachiopod from the Cretaceous of Sergipe, Brazil, with a restudy of 'Lingula' bagualensis Wilckens, 1905 from southern Patagonia
- 2009
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Ingår i: Palaeontologische Zeitschrift. - : Springer Science and Business Media LLC. - 0031-0220 .- 1867-6812. ; 83:2, s. 255-266
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Tidskriftsartikel (refereegranskat)abstract
- The lingulid brachiopod Lingularia? notialis sp. nov. is described from the upper Turonian (Cretaceous) of the Sergipe Basin in northeastern Brazil. The rare but well-preserved new material shows morphological characters such as muscle scars, mantle canals and a baculate shell structure. In a preliminary note L.? notialis was referred to Lingularia? bagualensis (Wilckens, 1905) from the uppermost Cretaceous of southern Patagonia, a species restudied here and referred conditionally to Credolingula Smirnova in Smirnova and Ushatinskaya, 2001.
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| 9. |
- Löfgren, Anita
(författare)
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An Oistodus venustus-like conodont species from the Middle Ordovician of Baltoscandia
- 2006
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Ingår i: Palaeontologische Zeitschrift. - 1867-6812. ; 80:1, s. 12-21
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Tidskriftsartikel (refereegranskat)abstract
- Ordovician conodont specimens resembling Oistodus venustus STAUFFER, 1935 have been reported from many areas. There is increasing evidence, however, that several lineages with homeomorphic conodont elements have erroneously been referred to one and the same species. I have investigated Baltoscandian conodont elements of this kind in order to find out about their origins and phylogenetic relationships with morphologically comparable elements from other areas. A natural grouping of finds from the Middle and lower Upper Ordovician of Baltoscandia is here described as belonging to a new species of a new genus, Venoistodus balticus n. gen., n. sp. The new species probably evolved paedomorphically from Drepanoistodus forceps (LINDSTROM, 1955) in the Early Ordovician.
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| 10. |
- Peel, John S.
(författare)
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Dasyclad-like problematic fossils from the lower Cambrian of North Greenland
- 2014
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Ingår i: Palaeontologische Zeitschrift. - : Springer Science and Business Media LLC. - 0031-0220 .- 1867-6812. ; 88:4, s. 367-374
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Tidskriftsartikel (refereegranskat)abstract
- The problematic fossil Kordesphecia nyeboensis gen. et sp. nov. from the lower Cambrian of North Greenland resembles the slightly younger, putative dasycladalean alga Amgaella Korde, 1957 in terms of its spirally arranged rhombic cells and central cavity. It differs in adding new cells through the sequential addition of roofing plates ('shingles') to pre-existing cell rows rather than encrusting lateral branches in dasycladalean fashion, in which character it seems comparable to the contemporaneous Lenaella Korde, 1959) from Siberia of unknown affinity. Kordesphecia is classified as incertae sedis but may be a stem-group dasycladalean.
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