| 1. |
- Alvarez, Maria Eugenia Dies, et al.
(författare)
-
Bradoriid arthropods from the lower-middle Cambrian of Scania, Sweden
- 2008
-
Ingår i: Acta Palaeontologica Polonica. - 0567-7920. ; 53:4, s. 647-656
-
Tidskriftsartikel (refereegranskat)abstract
- Three species of bradoriid arthropods from the lower to middle Cambrian transitional interval of Scania, southern Sweden, are described and illustrated: Beyrichona tines from the top of the traditional lower Cambrian (Gislov Formation: Ornamentaspis? linnarssoni Zone), and Hipponicharion eos and Alutella sp. from the basal portion of the traditional middle Cambrian (lowermost part of the Alum Shale Formation). The bradoriid fauna compares most closely with others previously described from western and eastern Avalonia (New Brunswick and England). The record of B. tinea suggests a correlation between the "Protolenus Zone" (Hupeolenus Zone) of western Avalonia and the O.? linnarssoni Zone of Scandinavia. Hipponicharion eos appears to be a fairly long-ranging species as it has previously been recorded from upper lower Cambrian or lower middle Cambrian strata in New Brunswick, Poland, and probably Sardinia. The record of H. eos from the lowermost part of the Alum Shale Formation suggests that this largely unfossiliferous interval in the Scanian succession is not younger than the Acadoparadoxides oelandicus Superzone. The genus Alutella has not previously been recorded from the Acado-Baltic Province.
|
|
| 2. |
- Chirivella Martorell, Juan B., et al.
(författare)
-
A blind trilobite with Baltic affinities from Cambrian Series 3 of the Iberian Chains, Spain, and its stratigraphical and palaeobiogeographical significance
- 2015
-
Ingår i: GFF. - : Informa UK Limited. - 2000-0863 .- 1103-5897. ; 137:3, s. 175-180
-
Tidskriftsartikel (refereegranskat)abstract
- Three cranidia of a conocoryphid trilobite are described from the lower Caesaraugustan Regional Stage (upper part of provisional Cambrian Stage 5 within Cambrian Series 3) in the Iberian Chains, Spain. The material is from the upper part of the Mansilla Formation and the base of the overlying Murero Formation. It closely resembles Bailiella tenuicincta (Linnarsson, 1879), which has previously been described from the Ptychagnostus gibbus (Cambrian Stage 5) and lower P. atavus zones (lower Drumian Stage) of Baltica (Sweden and Bornholm), and from the P. atavus Zone of West Avalonia (Newfoundland). The record of B. cf. tenuicincta from the Mediterranean margin of West Gondwana provides additional evidence for considering the Acado-Baltic region a discrete biogeographical province, at least during the Cambrian 5 and Drumian ages.
|
|
| 3. |
|
|
| 4. |
|
|
| 5. |
- Dies Alvarez, Maria Eugenia, et al.
(författare)
-
Paradoxides brachyrhachis Linnarsson, 1883 versus Paradoxides mediterraneus Pompeckj, 1901: a problematic determination
- 2010
-
Ingår i: GFF. - : Informa UK Limited. - 2000-0863 .- 1103-5897. ; 132:2, s. 95-104
-
Tidskriftsartikel (refereegranskat)abstract
- A revision of paradoxidid trilobites reveals that previous identifications of specimens from Sardinia and Spain as the Nordic trilobite species Paradoxides brachyrhachis Linnarsson, 1883, are mistaken. The southern species, occurring also in France, is here referred to Eccaparadoxides mediterraneus (Pompeckj, 1901). Main differences are seen in the preocular field, pleural furrow and pygidium. The species P. brachyrhachis is referred with question to the genus Mawddachites Fletcher 2007.
|
|
| 6. |
- Gamez Vintaned, Jose Antonio, et al.
(författare)
-
Trace and soft body fossils from the Pedroche Formation (Ovetian, Lower Cambrian of the Sierra de Cordoba, S Spain) and their relation to the Pedroche event
- 2006
-
Ingår i: Geobios. - : Elsevier BV. - 0016-6995. ; 39:4, s. 443-468
-
Tidskriftsartikel (refereegranskat)abstract
- The low Lower Cambrian rocks from the Sierra de Cordoba contain one of the best successions in Europe, which consists of well exposed mixed facies with abundant fossil assemblages showing long stratigraphical ranges throughout the Pedroche Formation. These assemblages include diverse Ovetian archaeocyaths, trilobites, small shelly fossils, calcimicrobes, trace fossils and stromatolites. Trace fossils are still poorly known, and thus they are the main objective of this work. Ichnological data are obtained from the Arroyo de Pedroche 1, Arroyo de Pedroche 2 and Puente de Hierro sections. Trace fossils include the ichnogenera Bergaueria, aff. Bilinichnus, Cochlichnus, aff. Cosmorhaphe?, Cylindrichnus, Dactyloidites, Dimorphichnus, Diplichnites, Monocraterion, Palaeophycus, aff. Phycodes, Planolites, Psammichnites, Rusophycus, Skolithos, Torrowangea and Treptichnus, as well as faecal pellets, meniscate trace fossils and others. They are abundant in shales and sandstones, and indicate important changes in the benthic conditions with respect to the underlying Torrearboles Formation. Changes in fossil assemblages within Member I of the Pedroche Formation indicate palaeoccological disruptions, which led to the disappearance of numerous archaeocyath species and the decrease of stromatolite biodiversity. This was followed by dominance of trilobite and brachiopod assemblages, accompanied by trace fossils of the Psammichnites ichnosp. A ichnoassociation. This biotic turnover (Pedroche event) occurred at the lower part of the archaeocyath Zone III, within the Bigotina bivallata biozone. The diagnoses of the ichnospecies Cochlichnus anguineus and Dactyloidites cabanasi are emended. (c) 2006 Elsevier SAS. All rights reserved.
|
|
| 7. |
|
|
| 8. |
- Linani, Eladio, et al.
(författare)
-
New lower Ovetian trilobites (low lower Cambrian) from Sierra Morena (Spain)
- 2008
-
Ingår i: Ameghiniana. - 0002-7014. ; 45:1, s. 123-138
-
Tidskriftsartikel (refereegranskat)abstract
- Trilobites from two lower Ovetian (low lower Cambrian) localities in Sierra Morena (south of Spain) are described. Serrania palaciosi nov. sp. and Serrania? gordaensis nov. sp. come from the western locality (Alconera). New specimens of Serrania verae Linan Guijarro, 1978 come from the eastern locality (Sierra de Cordoba). The ontogenetic study of S. verae suggests that this species evolved from S. palaciosi. The new material allows us to include the genus Serrania within the new subfamily Serrinae defined herein, belonging to the family Bigotinidae. We include also two more genera with a lateral spine in the glabella, Hupetina and Sdzuyia. According to its stratigraphical position and the associated taxa, we can determinate that S. verae belongs to the Lemdadella linaresae Zone, corresponding to the lower part of the archaeocyatids Zone III. On the basis of stratigraphic and phylogenetic criteria, S. palaciosi nov. sp. and S.? gordaensis nov. sp. from Alconera belong probably to the Zone I of archaeocyathids. Some unclassifiable trilobite fragments have been also found in the Zone I of archaeocyathids at the Ovetian stratotype in Sierra de Cordoba, below the trilobite zone of Bigotina bivallata (which is equivalent to the trilobite Zone 0, or Eofallotaspis Zone, of Morocco). The new species defined herein are, up to now, the oldest trilobites described from Gondwana.
|
|
| 9. |
|
|
| 10. |
- Zhang, Xingliang, et al.
(författare)
-
Challenges in defining the base of Cambrian Series 2 and Stage 3
- 2017
-
Ingår i: Earth-Science Reviews. - : Elsevier BV. - 0012-8252. ; 172, s. 124-139
-
Tidskriftsartikel (refereegranskat)abstract
- Formal subdivision of the Cambrian System into four series and ten stages is in progress. The base of Cambrian Stage 3 (provisional), which is conterminous with the base of Cambrian Series 2 (provisional), is expected to be placed at a horizon close to the first appearance of trilobites, which marks the onset of the largest phase of the Cambrian explosion. Conceptually, an ideal boundary position would be marked by a significant and globally recognizable bioevent that divides the lower part of the Cambrian System into a sub-trilobitic Terreneuvian Series and a trilobite-dominated Series 2. If the level is to be identified principally through biostratigraphic means, its position also needs to be recognizable using non-biostratigraphic means, and its correlation potential should be tested through detailed investigation of several continuous successions embracing the critical interval. Major difficulties in identifying a suitable horizon include strong biotic provincialism, a plethora of regional unconformities, and facies changes on different paleocontinents in the Cambrian Terreneuvian–Series 2 boundary interval. Levels that provide potential for intercontinental correlation include the first appearance position of trilobites and the approximately equivalent first appearance positions of certain small shelly fossil and acritarch species. In addition, a non-biostratigraphic marker, such as a stable carbon isotopic excursion, may be useful as a correlation level. Cambrian Series 2 and Stage 3 are provisional stratigraphic units, and their conterminous base was previously suggested to coincide to the appearance of trilobites. Compared to other potential chronostratigraphic indicators, the first appearance of trilobites still has advantages for recognizing and correlating the base of Stage 3, and should remain as the provisional primary marker for the boundary position.
|
|
