Christian Klug | University of Zurich, Switzerland (original) (raw)

Papers by Christian Klug

Research paper thumbnail of Phosphatized adductor muscle remains in a Cenomanian limid bivalve from Villers-sur-Mer (France)

Swiss Journal of Palaeontology

Soft-tissue preservation in molluscs is generally rare, particularly in bivalves and gastropods. ... more Soft-tissue preservation in molluscs is generally rare, particularly in bivalves and gastropods. Here, we report a three-dimensionally preserved specimen of the limid Acesta clypeiformis from the Cenomanian of France that shows preservation of organic structures of the adductor muscles. Examination under UV-light revealed likely phosphatisation of organic remains, which was corroborated by EDX-analyses. We suggest that the parts of the adductor muscles that are very close to the attachment are particularly resistant to decay and thus may be preserved even under taphonomic conditions usually not favouring soft-tissue fossilisation.

Research paper thumbnail of Is the relative thickness of ammonoid septa influenced by ocean acidification, phylogenetic relationships and palaeogeographic position?

Swiss Journal of Palaeontology

The impact of increasing atmospheric CO2 and the resulting decreasing pH of seawater are in the f... more The impact of increasing atmospheric CO2 and the resulting decreasing pH of seawater are in the focus of current environmental research. These factors cause problems for marine calcifiers such as reduced calcification rates and the dissolution of calcareous skeletons. While the impact on recent organisms is well established, little is known about long-term evolutionary consequences. Here, we assessed whether ammonoids reacted to environmental change by changing septal thickness. We measured the septal thickness of ammonoid phragmocones through ontogeny in order to test the hypothesis that atmospheric pCO2, seawater pH and other factors affected aragonite biomineralisation in ammonoids. Particularly, we studied septal thickness of ammonoids before and after the ocean acidification event in the latest Triassic until the Early Cretaceous. Early Jurassic ammonoid lineages had thinner septa relative to diameter than their Late Triassic relatives, which we tentatively interpret as consequ...

Research paper thumbnail of Palaeontology

Research paper thumbnail of The early elasmobranch Phoebodus : phylogenetic relationships, ecomorphology and a new time-scale for shark evolution

Proceedings of the Royal Society B: Biological Sciences, 2019

Anatomical knowledge of early chondrichthyans and estimates of their phylogeny are improving, but... more Anatomical knowledge of early chondrichthyans and estimates of their phylogeny are improving, but many taxa are still known only from microremains. The nearly cosmopolitan and regionally abundant Devonian genus Phoebodus has long been known solely from isolated teeth and fin spines. Here, we report the first skeletal remains of Phoebodus from the Famennian (Late Devonian) of the Maïder region of Morocco, revealing an anguilliform body, specialized braincase, hyoid arch, elongate jaws and rostrum, complementing its characteristic dentition and ctenacanth fin spines preceding both dorsal fins. Several of these features corroborate a likely close relationship with the Carboniferous species Thrinacodus gracia , and phylogenetic analysis places both taxa securely as members of the elasmobranch stem lineage. Identified as such, phoebodont teeth provide a plausible marker for range extension of the elasmobranchs into the Middle Devonian, thus providing a new minimum date for the origin of ...

Research paper thumbnail of Anatomy and evolution of the first Coleoidea in the Carboniferous

Communications Biology, 2019

Research paper thumbnail of Predatory behaviour and taphonomy of a Jurassic belemnoid coleoid (Diplobelida, Cephalopoda)

Research paper thumbnail of Palaeozoic evolution of animal mouthparts

Bulletin of Geosciences, 2017

Research paper thumbnail of Ecological Change during the early Emsian (Devonian) in the Tafilalt (Morocco), the Origin of the Ammonoidea, and the First African Pyrgocystid Edrioasteroids, Machaerids and Phyllocarids

Palaeontographica Abteilung A, 2008

Abstract Early Emsian claystones and marls of the Tafilalt yielded two diverse and prolific fauna... more Abstract Early Emsian claystones and marls of the Tafilalt yielded two diverse and prolific faunas with nearly 5000 specimens belonging to at least 100 species being recovered and identified. The older of the two faunas contains what may be the oldest bactritids, pyrgocystid edrioasteroids, phyllocarid carapaces, complete asteropygid trilobites, acanthodian fin spines rarely preserved as pairs, and articulated machaeridians. Additionally, the lower interval yielded a diverse and largely infaunal bivalve assemblage. The younger fauna is ...

Research paper thumbnail of Cephalopod associations and palaeoecology of the Cretaceous (Barremian–Cenomanian) succession of the Alpstein, northeastern Switzerland

Cretaceous Research, 2017

Research paper thumbnail of Intraspecific variation of phragmocone chamber volumes throughout ontogeny in the modern nautilidNautilusand the Jurassic ammoniteNormannites

PeerJ, 2015

Nautilusremains of great interest to palaeontologists after a long history of actualistic compari... more Nautilusremains of great interest to palaeontologists after a long history of actualistic comparisons and speculations on aspects of the palaeoecology of fossil cephalopods, which are otherwise impossible to assess. Although a large amount of work has been dedicated toNautilusecology, conch geometry and volumes of shell parts and chambers have been studied less frequently. In addition, although the focus on volumetric analyses for ammonites has been increasing recently with the development of computed tomographic technology, the intraspecific variation of volumetric parameters has never been examined. To investigate the intraspecific variation of the phragmocone chamber volumes throughout ontogeny, 30 specimens of RecentNautilus pompiliusand two Middle Jurassic ammonites (Normannites mitis) were reconstructed using computed tomography and grinding tomography, respectively. Both of the ontogenetic growth trajectories from the twoNormannitesdemonstrate logistic increase. However, a co...

Research paper thumbnail of A new Plesioteuthis with beak from the Kimmeridgian of Nusplingen (Germany)

Research paper thumbnail of An earliest Hettangian (Jurassic) belemnitid from Great Britain with a preserved proostracum

Research paper thumbnail of New anatomical information on arms and fins from exceptionally preserved Plesioteuthis (Coleoidea) from the Late Jurassic of Germany

Swiss Journal of Palaeontology, 2015

Research paper thumbnail of Latitudinal shifts of Palaeozoic marine invertebrate gigantism and global change

Since the Cambrian Explosion, giant marine invertebrate species have evolved iteratively in sever... more Since the Cambrian Explosion, giant marine invertebrate species have evolved iteratively in several groups. In the Palaeozoic, marine invertebrate gigantism was heterogeneously distributed through time and space; changes in maximum sizes show no clear relationship with atmospheric or oceanic oxygen and other environmental factors. Although gigantism has found an explanation for Carboniferous land invertebrates in the atmospheric oxygen peak, marine gigantism has not been studied empirically and explained comprehensively. By quantifying the spatiotemporal distribution of the largest representatives of some major marine invertebrate clades, we assessed links between ecological parameters and giant growth. These occurrence data suggest that temperature and latitude in combination with oxygen played important roles. Marine invertebrate gigantism developed in certain phases and regions with a greater number of extremely large species and their occurrences shifted independently from middle towards low latitudes during the Palaeozoic in all examined groups. This trend roughly coincides with the Late Devonian to Carboniferous cooling and regression as well as with a rise in atmospheric oxygen. This shows how global environmental changes can control the geographical distribution of organisms and that the optimal ecological requirements might differ depending on body size: extremely large organisms might react less flexibly to ecological changes.

Research paper thumbnail of The first record of Early Devonian ammonoids from Belgium and their stratigraphic significance

Geologica Belgica

The first ammonoids from the Lower Emsian (Devonian) of Belgium are described. They belong to the... more The first ammonoids from the Lower Emsian (Devonian) of Belgium are described. They belong to the Anetoceratinae, which show the most plesiomorphic characters of all ammonoids. This is the second report of Early Emsian ammonoids within the Rhenish facies of the Rhenish Slate Mountains (Belgium, Germany), in this case from the Belgian part of the Eifel (Burg Reuland). It highlights the possible importance of ammonoids for the correlation of the Emsian in its traditional German sense and the Emsian in the global sense as delimited by the GSSPs. Newly collected, age-significant brachiopods of the genera Arduspirifer and Euryspirifer and other previously reported fossils indicate a middle or late Early Emsian (Singhofen or Vallendar) age (in German sense) for this locality. We extend the range of Ivoites schindewolfi outside of the Hunsrück Basin and further corroborate an age younger than Ulmen for parts of the Hunsrück Slate.

Research paper thumbnail of Ancestry, Origin and Early Evolution of Ammonoids

Topics in Geobiology, 2015

In order to put the origin of the Ammonoidea into the broader evolutionary context, we review the... more In order to put the origin of the Ammonoidea into the broader evolutionary context, we review the hypothesis on the origin of cephalopods in general, the origin of bactritids as well as the origin of bactritids with their respective Bauplan characters. We also list major morphological changes that occurred between the origin of cephalopods until the early evolution of ammonoids.

Research paper thumbnail of Taxonomic Diversity and Morphological Disparity of Paleozoic Ammonoids

Topics in Geobiology, 2015

Research paper thumbnail of Mature Modifications and Sexual Dimorphism

Topics in Geobiology, 2015

Research paper thumbnail of Taphonomy and palaeoecology of the green Devonian gypidulid brachiopods from the Aferdou El Mrakib, eastern Anti-Atlas, Morocco

Swiss Journal of Palaeontology, 2013

Research paper thumbnail of Reply to “Ichthyosaur embryos outside the mother body: not due to carcass explosion but to carcass implosion” by van Loon (2013)

Palaeobiodiversity and Palaeoenvironments, 2014

Research paper thumbnail of Phosphatized adductor muscle remains in a Cenomanian limid bivalve from Villers-sur-Mer (France)

Swiss Journal of Palaeontology

Soft-tissue preservation in molluscs is generally rare, particularly in bivalves and gastropods. ... more Soft-tissue preservation in molluscs is generally rare, particularly in bivalves and gastropods. Here, we report a three-dimensionally preserved specimen of the limid Acesta clypeiformis from the Cenomanian of France that shows preservation of organic structures of the adductor muscles. Examination under UV-light revealed likely phosphatisation of organic remains, which was corroborated by EDX-analyses. We suggest that the parts of the adductor muscles that are very close to the attachment are particularly resistant to decay and thus may be preserved even under taphonomic conditions usually not favouring soft-tissue fossilisation.

Research paper thumbnail of Is the relative thickness of ammonoid septa influenced by ocean acidification, phylogenetic relationships and palaeogeographic position?

Swiss Journal of Palaeontology

The impact of increasing atmospheric CO2 and the resulting decreasing pH of seawater are in the f... more The impact of increasing atmospheric CO2 and the resulting decreasing pH of seawater are in the focus of current environmental research. These factors cause problems for marine calcifiers such as reduced calcification rates and the dissolution of calcareous skeletons. While the impact on recent organisms is well established, little is known about long-term evolutionary consequences. Here, we assessed whether ammonoids reacted to environmental change by changing septal thickness. We measured the septal thickness of ammonoid phragmocones through ontogeny in order to test the hypothesis that atmospheric pCO2, seawater pH and other factors affected aragonite biomineralisation in ammonoids. Particularly, we studied septal thickness of ammonoids before and after the ocean acidification event in the latest Triassic until the Early Cretaceous. Early Jurassic ammonoid lineages had thinner septa relative to diameter than their Late Triassic relatives, which we tentatively interpret as consequ...

Research paper thumbnail of Palaeontology

Research paper thumbnail of The early elasmobranch Phoebodus : phylogenetic relationships, ecomorphology and a new time-scale for shark evolution

Proceedings of the Royal Society B: Biological Sciences, 2019

Anatomical knowledge of early chondrichthyans and estimates of their phylogeny are improving, but... more Anatomical knowledge of early chondrichthyans and estimates of their phylogeny are improving, but many taxa are still known only from microremains. The nearly cosmopolitan and regionally abundant Devonian genus Phoebodus has long been known solely from isolated teeth and fin spines. Here, we report the first skeletal remains of Phoebodus from the Famennian (Late Devonian) of the Maïder region of Morocco, revealing an anguilliform body, specialized braincase, hyoid arch, elongate jaws and rostrum, complementing its characteristic dentition and ctenacanth fin spines preceding both dorsal fins. Several of these features corroborate a likely close relationship with the Carboniferous species Thrinacodus gracia , and phylogenetic analysis places both taxa securely as members of the elasmobranch stem lineage. Identified as such, phoebodont teeth provide a plausible marker for range extension of the elasmobranchs into the Middle Devonian, thus providing a new minimum date for the origin of ...

Research paper thumbnail of Anatomy and evolution of the first Coleoidea in the Carboniferous

Communications Biology, 2019

Research paper thumbnail of Predatory behaviour and taphonomy of a Jurassic belemnoid coleoid (Diplobelida, Cephalopoda)

Research paper thumbnail of Palaeozoic evolution of animal mouthparts

Bulletin of Geosciences, 2017

Research paper thumbnail of Ecological Change during the early Emsian (Devonian) in the Tafilalt (Morocco), the Origin of the Ammonoidea, and the First African Pyrgocystid Edrioasteroids, Machaerids and Phyllocarids

Palaeontographica Abteilung A, 2008

Abstract Early Emsian claystones and marls of the Tafilalt yielded two diverse and prolific fauna... more Abstract Early Emsian claystones and marls of the Tafilalt yielded two diverse and prolific faunas with nearly 5000 specimens belonging to at least 100 species being recovered and identified. The older of the two faunas contains what may be the oldest bactritids, pyrgocystid edrioasteroids, phyllocarid carapaces, complete asteropygid trilobites, acanthodian fin spines rarely preserved as pairs, and articulated machaeridians. Additionally, the lower interval yielded a diverse and largely infaunal bivalve assemblage. The younger fauna is ...

Research paper thumbnail of Cephalopod associations and palaeoecology of the Cretaceous (Barremian–Cenomanian) succession of the Alpstein, northeastern Switzerland

Cretaceous Research, 2017

Research paper thumbnail of Intraspecific variation of phragmocone chamber volumes throughout ontogeny in the modern nautilidNautilusand the Jurassic ammoniteNormannites

PeerJ, 2015

Nautilusremains of great interest to palaeontologists after a long history of actualistic compari... more Nautilusremains of great interest to palaeontologists after a long history of actualistic comparisons and speculations on aspects of the palaeoecology of fossil cephalopods, which are otherwise impossible to assess. Although a large amount of work has been dedicated toNautilusecology, conch geometry and volumes of shell parts and chambers have been studied less frequently. In addition, although the focus on volumetric analyses for ammonites has been increasing recently with the development of computed tomographic technology, the intraspecific variation of volumetric parameters has never been examined. To investigate the intraspecific variation of the phragmocone chamber volumes throughout ontogeny, 30 specimens of RecentNautilus pompiliusand two Middle Jurassic ammonites (Normannites mitis) were reconstructed using computed tomography and grinding tomography, respectively. Both of the ontogenetic growth trajectories from the twoNormannitesdemonstrate logistic increase. However, a co...

Research paper thumbnail of A new Plesioteuthis with beak from the Kimmeridgian of Nusplingen (Germany)

Research paper thumbnail of An earliest Hettangian (Jurassic) belemnitid from Great Britain with a preserved proostracum

Research paper thumbnail of New anatomical information on arms and fins from exceptionally preserved Plesioteuthis (Coleoidea) from the Late Jurassic of Germany

Swiss Journal of Palaeontology, 2015

Research paper thumbnail of Latitudinal shifts of Palaeozoic marine invertebrate gigantism and global change

Since the Cambrian Explosion, giant marine invertebrate species have evolved iteratively in sever... more Since the Cambrian Explosion, giant marine invertebrate species have evolved iteratively in several groups. In the Palaeozoic, marine invertebrate gigantism was heterogeneously distributed through time and space; changes in maximum sizes show no clear relationship with atmospheric or oceanic oxygen and other environmental factors. Although gigantism has found an explanation for Carboniferous land invertebrates in the atmospheric oxygen peak, marine gigantism has not been studied empirically and explained comprehensively. By quantifying the spatiotemporal distribution of the largest representatives of some major marine invertebrate clades, we assessed links between ecological parameters and giant growth. These occurrence data suggest that temperature and latitude in combination with oxygen played important roles. Marine invertebrate gigantism developed in certain phases and regions with a greater number of extremely large species and their occurrences shifted independently from middle towards low latitudes during the Palaeozoic in all examined groups. This trend roughly coincides with the Late Devonian to Carboniferous cooling and regression as well as with a rise in atmospheric oxygen. This shows how global environmental changes can control the geographical distribution of organisms and that the optimal ecological requirements might differ depending on body size: extremely large organisms might react less flexibly to ecological changes.

Research paper thumbnail of The first record of Early Devonian ammonoids from Belgium and their stratigraphic significance

Geologica Belgica

The first ammonoids from the Lower Emsian (Devonian) of Belgium are described. They belong to the... more The first ammonoids from the Lower Emsian (Devonian) of Belgium are described. They belong to the Anetoceratinae, which show the most plesiomorphic characters of all ammonoids. This is the second report of Early Emsian ammonoids within the Rhenish facies of the Rhenish Slate Mountains (Belgium, Germany), in this case from the Belgian part of the Eifel (Burg Reuland). It highlights the possible importance of ammonoids for the correlation of the Emsian in its traditional German sense and the Emsian in the global sense as delimited by the GSSPs. Newly collected, age-significant brachiopods of the genera Arduspirifer and Euryspirifer and other previously reported fossils indicate a middle or late Early Emsian (Singhofen or Vallendar) age (in German sense) for this locality. We extend the range of Ivoites schindewolfi outside of the Hunsrück Basin and further corroborate an age younger than Ulmen for parts of the Hunsrück Slate.

Research paper thumbnail of Ancestry, Origin and Early Evolution of Ammonoids

Topics in Geobiology, 2015

In order to put the origin of the Ammonoidea into the broader evolutionary context, we review the... more In order to put the origin of the Ammonoidea into the broader evolutionary context, we review the hypothesis on the origin of cephalopods in general, the origin of bactritids as well as the origin of bactritids with their respective Bauplan characters. We also list major morphological changes that occurred between the origin of cephalopods until the early evolution of ammonoids.

Research paper thumbnail of Taxonomic Diversity and Morphological Disparity of Paleozoic Ammonoids

Topics in Geobiology, 2015

Research paper thumbnail of Mature Modifications and Sexual Dimorphism

Topics in Geobiology, 2015

Research paper thumbnail of Taphonomy and palaeoecology of the green Devonian gypidulid brachiopods from the Aferdou El Mrakib, eastern Anti-Atlas, Morocco

Swiss Journal of Palaeontology, 2013

Research paper thumbnail of Reply to “Ichthyosaur embryos outside the mother body: not due to carcass explosion but to carcass implosion” by van Loon (2013)

Palaeobiodiversity and Palaeoenvironments, 2014