Silurian global events – at the tipping point of climate change

Calner, Mikael

doi:10.1007/978-3-540-75916-4_4

Cited by 86 publications

(73 citation statements)

References 76 publications

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“…This is not surprising considering that the event is associated with the largest positive carbon isotope excursion of the Phanerozoic (Lehnert et al 2003, Munnecke et al 2003, dramatic faunal turnovers (see summary in Jeppsson & Aldridge 2000, Calner 2008) and a collapse of the marine ecosystem (Calner 2005). Profound biotic changes have been recorded, e.g., among conodonts (Jeppsson & Aldridge 2000), acritarchs (Stricanne et al 2006), graptolites (Urbanek 1993, Štorch 1995, Melchin et al 1998, Manda et al 2012, cephalopods (Manda 2008) and fish ).…”

Section: The Kozlowskii/lau Event and Its Influence On The Polychaetementioning

confidence: 97%

A jawed polychaete fauna from the late Ludlow Kozlowskii event interval in the Prague Basin (Czech Republic)

Tonarová¹,

Eriksson²,

Hints³

2012

Bull. Geosci.

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Section: The Kozlowskii/lau Event and Its Influence On The Polychaetementioning

confidence: 97%

A jawed polychaete fauna from the late Ludlow Kozlowskii event interval in the Prague Basin (Czech Republic)

Tonarová¹,

Eriksson²,

Hints³

2012

Bull. Geosci.

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“…This level corresponds with the onset of the Kozlowskii and Lau extinction event (Urbanek 1993, Calner 2008, Manda et al 2012. Three paleopopulations were examined, from three thin beds with erosive surfaces, each representing a single depositional event: Zadní KopaninaNad Jirasovým lomem, bed No.…”

Section: Variabilitymentioning

confidence: 99%

"An endocochleate experiment" in the Silurian straight-shelled cephalopod Sphooceras

Turek¹,

Manda²

2012

Bull. Geosci.

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Sphooceras truncatum (Barrande, 1860), a Silurian straight-shelled cephalopod with a short finger-shaped shell, is one of a few cephalopods in which natural truncation of the apical part of the phragmocone from the rest of the conch is confirmed. Periodic natural removal of the apical part of the shell (4 to 5 phragmocone chambers) preceded formation of a terminal callus and a calcareous plug closing the septal foramen. The apical callus probably originated by fusion of the truncation septum with episeptal deposits. These structures temporarily formed the new apex on which two additional calcareous layers had been secreted. A unique specimen preserves a colour pattern in the convex apical region, which proves that the shell in Sphooceras was temporarily completely surrounded by mantle extending from the body chamber, i.e. the cephalopod was at least temporarily endocochleate. The co-occurrence of different growth stages of S. truncatum together with one type of short juvenile orthoceracone shell, with a maximum of eight phragmocone chambers and a very small subglobular initial chamber indicates that these embryonic shells may belong to Sphooceras. Two other genera are discussed, both previously included in the family Sphooceratidae: Disjunctoceras Gnoli in Kiselev, 1992 and Andigenoceras Gnoli in Kiselev, 1992. The newly discovered thickening of the apex in "Disjunctoceras" disjunctum, the type species of Disjunctoceras, indicates that this species does not differ substantially from Sphooceras and should be reassigned to this genus. Similarly, representatives of Andigenoceras also possess characteristic features of Sphooceras. Sphooceras has many features characteristic for modern cephalopods: short, thin-walled, semi-internal shell; phragmocone reduced to only a few chambers; uncalcified connecting rings; apical callus (a structure analogous to the belemnite rostrum); retractor muscle scars situated dorsally; very small protoconch without cicatrix. In some exceptionally well-preserved cephalopods with orthoceracone shell radula with seven rows of teeth were observed. All these features support the thesis that some straight-shelled cephalopods are evolutionarily closer to coleoids than nautiloids and their separation from nautiloids is legitimate. Vascular imprints on the surface of the cameral deposits provide further support for their primary origin and the existence of a cameral mantle. The character of cameral deposits in Sphooceras demonstrates that the systematic value of these structures in other straight-shelled cephalopods, a subject of controversy, has limited value. The morphology of Sphooceras also demonstrates that the boundary between endocochleate and ectocochleate cephalopods is not sharp, i.e. internalisation of the shell in cephalopods occurred repeatedly.•

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“…The time of the conodont Lau Event is regarded by some authors as one of the most conspicuous oceanic events (see review by Calner 2008). The event proper was originally postulated, because several conodont taxa disappeared in a stepwise extinction that started before the last appearance datum (LAD) of the conodont taxon Polygnathoides siluricus Branson & Mehl, 1933 in the upper part of the Hemse beds on Gotland.…”

Section: The Lau Eventmentioning

confidence: 99%

Reflection of the mid-Ludfordian Lau Event in conodont faunas of Bohemia

Slavík¹,

Kříž²,

Carls³

2010

Bull. Geosci.

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Conodont faunas of the Polygnathoides siluricus Zone (Ludfordian, Ludlow) from shallow-water environments of Bohemia are characterized by relatively high taxonomic diversity that reflects an interval with taxa thriving due to increased nutrient supply in rather stable environments during the pre-Lau Event time, as has been documented globally. Although the conodont faunas in strata with P. siluricus are more diversified and variable than those in the interval instantly following, the uninterrupted ranges of several taxa (of genera Wurmiella, Ozarkodina and Delotaxis) show that the change in conodont faunas in the sections is not as drastic in Bohemia as described on Gotland and that the extinction rate was rather moderate. A detailed correlation of conodont distribution in the sections indicates, however, that a large part of the Lau Event is not preserved in the shallow water environment of the former Řeporyje Volcanic Elevation. Accordingly, timing and spatial image of the conodont extinction are thus partly obscured. Only a short interval with considerably diminished conodont elements during the lower range of Ozarkodina? snajdri with random occurrences of Pedavis latialatus, corresponds to the part of the "Icriodontid Zone" on Gotland, i.e. the uppermost part of the Lau Event. This incompleteness in record confirms sedimentary starvation in the shallow environment on the former volcanic elevation in this part of the Prague Basin.•

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Silurian global events – at the tipping point of climate change

Cited by 86 publications

References 76 publications

A jawed polychaete fauna from the late Ludlow Kozlowskii event interval in the Prague Basin (Czech Republic)

A jawed polychaete fauna from the late Ludlow Kozlowskii event interval in the Prague Basin (Czech Republic)

"An endocochleate experiment" in the Silurian straight-shelled cephalopod Sphooceras

Reflection of the mid-Ludfordian Lau Event in conodont faunas of Bohemia

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