Ravnholtvej 23

Juelsminde, Denmark

Ravnholtvej 23

Juelsminde, Denmark
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Ebbestad J.O.R.,Uppsala University | Weidner T.,Ravnholtvej 23
Palaeontology | Year: 2017

Pengia Geyer & Corbacho is a Cambrian burlingiid trilobite with fused trunk segments devoid of any articulation in the anamorphic and epimorphic phases of development. The type species is Pengia fusilis (Peng et al.) from the Wanshania wanshanensis Zone of China. Here we describe a second species, Pengia palsgaardia sp. nov., from the Lejopyge laevigata Zone of the Paradoxides forchhammeri Superzone. It comes from a glacial erratic in Denmark which probably originated in the Alum Shale Formation of Västergötland, Sweden. Pengia palsgaardia is a large burlingiid (~10 mm in length), with 14 fused segments in the trunk whose boundaries are marked by ridges. The axis is narrow, with the axial furrows faintly indicated or effaced across the median. Laterally along the axis and the tapering glabella, symmetrical globular lobes are developed that are pinched at their base. During ontogeny the glabellar furrows are pit-like adaxially but shallow towards the axial furrow as the globular lobes develop. Their pit-like appearance in Pengia palsgaardia and some other burlingiid species is not considered similar to the condition seen in oryctocephalid trilobites. A median preglabellar ridge resembling that of Schmalenseeia Moberg develops late in ontogeny but in early ontogeny the preglabellar field resembles that of Burlingia Walcott, Alumenella Geyer & Corbacho and Niordilobites Geyer & Corbacho. This gives Pengia a more basal position in the schmalenseeid lineage, outside the derived Schmalenseeia. In mature specimens the facial sutures in P. palsgaardia are fused, but an ocular suture may have been present. During ontogeny Pengia would have gone through the anamorphic and protomeric protaspid segmental conditions, but articulation between either the cephalon and pygidium, or pygidium and thoracic segments of the trunk never developed so it did not progress beyond the protaspid phase. This extreme protomeric development is considered to be a derived feature in Pengia. © The Palaeontological Association


Ebbestad J.O.R.,Uppsala University | Rushton A.W.A.,Natural History Museum in London | Stein M.,Natural History Museum of Denmark | Weidner T.,Ravnholtvej 23
GFF | Year: 2013

A mass aggregation of 148 paradoxidid trilobites and associated specimens of the agnostoid Pentagnostus praecurrens is preserved on a surface of a split orsten lens from the Middle Cambrian Series 3 Acadoparadoxides pinus-P. praecurrens Zone in Jämtland, Sweden. Most specimens are complete or nearly complete, lying parallel to the sediment surface and seem unaffected by currents or sorting. The association is interpreted as a moult ensemble. Paradoxidid specimens are represented by two taxa, identified as paradoxidid sp. 1 (n = 28 specimens) and Eccaparadoxides sp. 2 (n = 45 specimens). The species are preserved both dorsum up and dorsum down, in about equal number, which may reflect a natural tendency to moult in either posture. They probably moulted by opening the cephalic sutures along the wide rostrum. The dorsal sutures are invariably open and the librigenae are very often displaced, commonly backwards in relation to the cranidium, but not symmetrically in relation to the axial shield. The glabella of the paradoxidids is often crushed, so that sometimes the underlying hypostome is outlined. Very few examples show the joint between the cranidium and the trunk being broken. Facies interpretation suggests deposition below storm wave base. Rapid burial, possibly by blanketing from hypopycnal flows followed by an extended period of slow sediment input (Type 1 facies of Brett et al. 2012) may explain the unusual preservation. The animals may have lived in an ex-aerobic environment, but evidence to support this is at the moment insubstantial. © 2013 Copyright OPA (Overseas Publishers Association) N.V. Published by license under the Harwood Academic Publishers imprint, 2012.


Weidner T.,Ravnholtvej 23 | Rushton A.W.A.,Natural History Museum in London | Ebbestad J.O.R.,Uppsala University
GFF | Year: 2014

We describe faunas, formerly very little known, from allochthonous mid-Cambrian strata in the Fjällbränna Formation (Tåsjön Group) in Ångermanland that are equivalent to the “Paradoxides oelandicus Beds” of the autochthon. Paradoxidid trilobites are by far the commonest forms but are represented only by dissociated sclerites; 7–10 taxa appear to be present, but most of them are so incomplete that they cannot be identified with certainty. They are accompanied by rare agnostoids of two taxa, Pentagnostus praecurrens and Acadagnostus acadicus. The assemblages lack eodiscoid or other polymerid trilobites, molluscs and brachiopods, and in this respect contrast with shallower-water shelf faunas in the “Oelandicus Beds” of the Swedish autochthon, but bear comparison with shelf-edge or slope faunas from Novaya Zemlya (Arctic Russia), the Moesian Platform (Romania) and South Carolina (USA). © 2014, © 2014 Taylor & Francis.


Weidner T.,Ravnholtvej 23 | Nielsen A.T.,Copenhagen University
Journal of Systematic Palaeontology | Year: 2014

A newly collected trilobite fauna from the lowermost part of the Alum Shale Formation at Øleå, Bornholm, Denmark, demonstrates the presence of a thin but richly fossiliferous Middle Cambrian Acidusus atavus Zone (Paradoxides paradoxissimus Superzone). The lower part of the zone (the Tomagnostus fissus-Ptychagnostus atavus Zone of older Scandinavian literature) is represented by a discontinuous limestone bed, up to 20 cm thick, whereas the upper part (Hypagnostus parvifrons Zone of older literature) is represented by shale, less than 80 cm thick, containing lenses of bituminous limestone. A total of 39 agnostid and 21 polymerid species are recorded from the A. atavus Zone (including 12 taxa treated under open nomenclature). One additional polymerid species collected from an ice-rafted boulder derived from the Bornholm area is also treated. The fauna is described and illustrated, with designation and reillustration of relevant lectotypes. The abundance of polymerid trilobites in comparison with nearby Scania, southern Sweden, where 25 agnostid and nine polymerid species have been reported from equivalent strata, is indicative of a less dysoxic environment in the Bornholm area, which was probably uplifted. The trilobite fauna resembles the coeval assemblages described from England, Wales, eastern Newfoundland and eastern Siberia, sharing several species not reported previously from Baltica, including Anopolenus sp., Agraulos longicephalus, Bailiella ornata, Clarella impar, Solenopleura? applanata, Acadagnostus aff. bulkurensis and Phalagnostus ovalis. A few faunal elements originally described from Bohemia and Australia are also present, viz. Hydrocephalus aff. carens, Phalagnostus nudus, Skryjagnostus pompeckji, Hypagnostus aff. clipeus, Euagnostus aff. interstrictus and Euagnostus? aff. glandifer. © The Trustees of the Natural History Museum, London 2013.


Nielsen A.T.,Copenhagen University | Weidner T.,Ravnholtvej 23 | Terfelt F.,Lund University | Hoyberget M.,Rennesveien 14
GFF | Year: 2014

The traditional Furongian trilobite biozones of Scandinavia, recently proposed abandoned due to inconsistent boundary definitions [Terfelt, F., Eriksson, M.E., Ahlberg, P. & Babcock, L.E., 2008: Furongian Series (Cambrian) biostratigraphy of Scandinavia - a revision. Norwegian Journal of Geology88, 73-87], are resurrected and elevated to superzonal rank. These superzones are usually readily recognized in the field, even by non-specialists, and for general correlation and mapping the more wide-ranging biozones are considerably more practicable than the very detailed zonation (formerly subzonation) introduced by Terfelt et al. (2008). Formal definition of the superzones is outlined including designation of stratotype sections. The superzones are each defined by the FAD of a characterizing species group and upwards delimited by the base of the succeeding superzone. The long used Olenus, Parabolina and Leptoplastus (super)zones as well as the recently introduced Acerocarina Superzone (= Acerocare Zone of older literature) are maintained and formalized. The Protopeltura praecursor, Peltura minor and Peltura scarabaeoides zones are abandoned and replaced by two new units, named the Protopeltura and Peltura superzones, respectively. Accordingly, all Furongian superzones have a uniform naming style referring to a characteristic genus. The six Furongian superzones currently comprise 27 trilobite zones. The Paradoxides forchhammeri Superzone (Cambrian Series 3) is extended upwards to the base of the Olenus Superzone, thereby formally including the Agnostus pisiformis Zone. © 2014 © 2014 Taylor & Francis.


Weidner T.,Ravnholtvej 23 | Nielsen A.T.,Copenhagen University
GFF | Year: 2013

The traditional Furongian biozones of Scandinavia, based on olenid trilobites, are proposed elevated to superzonal rank. For the time being they are treated informally, except that the designation Acerocarina Superzone is proposed as replacement name for the uppermost superzone, formerly referred to as the Acerocare Zone. It comprises four zones. The lowest of these zones, hitherto referred to as the Peltura transiens Zone, is renamed as the Acerocarina granulata Zone. The distribution of the Acerocarina Superzone in Baltoscandia is mapped. A newly discovered 1.4 m thick succession on Kinnekulle, Västergötland, yielded Parabolina heres heres, P. transiens, Peltura costata, Peltura scarabaeoides westergaardi and Sphaerophthalmus alatus. In addition, A. granulata, Pelturina punctifera and Leptoplastides? sp. were collected from loose boulders deriving from the same interval. This is the first unambiguous record of P. costata and P. punctifera in Sweden. The fossil assemblage, assigned to the P. costata Zone, contains species hitherto considered characteristic of five different biozones, viz. the Ctenopyge tumida Zone, the Parabolina lobata Zone, the P. transiens Zone, the P. costata Zone and the Westergaardia scanica Zone. P. transiens, P. scarabaeoides westergaardi and S. alatus are assumed to have been reworked, whereas P. punctifera appears one zone earlier than in Norway. Parabolina (Parabolina) heres lata, not found during this study, may turn up in the P. costata Zone or even earlier. The Acerocarina Superzone is resting on the P. lobata Zone, and the intervening zone, characterized by Peltura paradoxa (uppermost "Peltura scarabaeoides" superzone), is missing in the succession on Kinnekulle. © 2013 Copyright.


Rushton A.W.A.,Natural History Museum in London | Weidner T.,Ravnholtvej 23
GFF | Year: 2010

New material of Irvingella from central Sweden includes a cranidium of Irvingella major which is associated with fragmentary olenid trilobites that represent the Parabolina brevispina Subzone of the P. spinulosa Zone. This affords a direct correlation between the olenid trilobite zonation of Baltica and the Irvingella major Zone at the base of the Sunwaptan Stage in Laurentia. Several topotypic cranidia of Irvingella suecica Westerga°rd confirm the features of that species but do not provide a direct indication of its position within the olenid zonal succession.


Anna Z.,University of Warsaw | Thomas W.,Ravnholtvej 23 | John A.,Backlyckevagen 4B | Per A.,Lund University
Acta Geologica Polonica | Year: 2015

Seventeen taxa of exotic trilobites representing eight families are described from the olenid- and agnostoid-dominated strata of the uppermost Cambrian Series 3 and lower Furongian alum shale facies of Sweden and from glacial erratic boulders of Denmark. Only five taxa are assigned to species level, i.e., Maladioidella abdita (Salter, 1866), Olentella rara (Westergård, 1922), Pedinocephalus peregrinus (Henningsmoen, 1957), Ptychoparia pusilla (Westergård, 1922), and Westergaardella olenorum (Westergård, 1922), whereas the others are left under open nomenclature or remain unrecognized. Most are described for the first time from the Cambrian of Scandinavia. Their affinities point to a strong connection with East Gondwana, Laurentia, Kazakhstania and Siberia. Exotic trilobites appear in the succession directly after periods of very low oxygen concentration in the Alum Shale Sea; their occurrences correspond to the ranges of agnostoid arthropods in the succession and seem to be linked to global transgressive events causing an influx of cool and/or oxygen-depleted waters onto the shelf of the Baltica palaeocontinent. © 2015 Wydawnictwo Naukowe INVIT. All rights reserved.


Weidner T.,Ravnholtvej 23 | Nielsen A.T.,Copenhagen University
Bulletin of the Geological Society of Denmark | Year: 2015

The trilobite genus Agraulos Hawle & Corda 1847 has within Scandinavia been recorded only from Bornholm, Denmark, where its representatives occur in the Middle Cambrian Paradoxides paradoxissimus Superzone of the Alum Shale Formation. Only cranidia have been found so far, representing Agraulos longicephalus (Hicks 1872) and the rare “Agraulos” depressus Grönwall 1902. The two species from Bornholm are redescribed and discussed based on museum collections in combination with newly collected material from Borggård, Øleå. Agraulos longicephalus occurs commonly in the lower and upper part of the Acidusus atavus Zone as well as in the Ptychagnostus punctuosus Zone. It closely resembles the coeval Agraulos ceticephalus (Barrande 1846) known from Bohemia and eastern Newfoundland. A lectotype for “Agraulos” depressus is designated and reillustrated; this taxon is hesitantly assigned to Proampyx? It is known only from the Ptychagnostus punctuosus Zone and may represent an early, atypical Proampyx or maybe a precursor that should be separated in a new genus. Emended diagnoses of Agraulos Hawle & Corda 1847 and Proampyx Frech 1897 are presented. © 2014, Dansk Geologisk Forening. All rights reserved.


Weidner T.,Ravnholtvej 23 | Nielsen A.T.,Copenhagen University
GFF | Year: 2015

Species assigned to the Middle Cambrian agnostid genus Tomagnostus are briefly reviewed and a large number of Tomagnostus sibiricus found in Scania, Sweden, are described. The material derives from the Triplagnostus gibbus Zone in the Exsulans Limestone. Several morphological features support an assignment of the species to Tomagnostus: occasional scrobiculation of the cephalon, half of the cephala have an incipient frontal sulcus, pygidia have well-developed F2 furrows, well-defined transverse depression on posteroaxis and occasionally minute marginal spines or swellings. One pygidium of the biostratigraphically important Pentagnostus praecurrens and one pygidium of the rare Onymagnostus seminula are also described from the Exsulans Limestone of Brantevik, Scania. The new findings expand the stratigraphic ranges of these species in Scandinavia. © 2014, © 2014 Taylor & Francis.

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