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Papers by Christian Klug

Ammonoids reached their greatest diversity during the Triassic period. In the early Middle Triass... more Ammonoids reached their greatest diversity during the Triassic period. In the early Middle Triassic (Anisian) stage, ammonoid diversity was dominated by representatives of the family Ceratitidae. High taxonomic diversity can, however, be decoupled from their morphologic disparity. Due to its high phenotypic variability, the high diversity of ceratitids of the Anisian of Nevada was initially assumed to be caused by artificial over-splitting. This study aims to contribute data to settle this issue by applying geometric morphometrics methods, using landmarks and semi-landmarks, in the study of ontogenetic cross-sections of ammonoids for the first time. The results reveal that alterations in ontogenetic trajectories, linked to heterochronic processes, lead to the morphologic diversification of the species studied herein. Our knowledge, based on these ontogenetic changes, challenge the traditional treatment of species using solely adult characters for their distinction. This study furthermore demonstrates that the high diversity of the Anisian ammonoid assemblages of Nevada based on the traditional nomenclatoric approach is regarded to be reasonably accurate.

Swiss journal of palaeontology, May 30, 2024

Belemnite rostra are very abundant in Mesozoic marine deposits in many regions. Despite this abun... more Belemnite rostra are very abundant in Mesozoic marine deposits in many regions. Despite this abundance, soft-tissue specimens of belemnites informing about anatomy and proportions of these coleoid cephalopods are extremely rare and limited to a few moderately large genera like Passaloteuthis and Hibolithes. For all other genera, we can make inferences on their body proportions and body as well as mantle length by extrapolating from complete material. We collected data of the proportions of the hard parts of some Jurassic belemnites in order to learn about shared characteristics in their gross anatomy. This knowledge is then applied to the Bajocian genus Megateuthis, which is the largest known belemnite genus worldwide. Our results provide simple ratios that can be used to estimate belemnite body size, where only the rostrum is known.

Swiss journal of palaeontology, Mar 4, 2024

Marine conservation deposits ('Konservat-Lagerstätten') are characterized by their mode of fossil... more Marine conservation deposits ('Konservat-Lagerstätten') are characterized by their mode of fossil preservation, faunal composition and sedimentary facies. Here, we review these characteristics with respect to the famous conservation deposit of the Besano Formation (formerly Grenzbitumenzone; including the Anisian-Ladinian boundary), and the successively younger fossil-bearing units Cava inferiore, Cava superiore, Cassina beds and the Kalkschieferzone of Monte San Giorgio (Switzerland and Italy). We compare these units to a selection of important black shale-type Lagerstätten of the global Phanerozoic plus the Ediacaran in order to detect commonalities in their facies, genesis, and fossil content using principal component and hierarchical cluster analyses. Further, we put the Monte San Giorgio type Fossillagerstätten into the context of other comparable Triassic deposits worldwide based on their fossil content. The results of the principal component and cluster analyses allow a subdivision of the 45 analysed Lagerstätten into four groups, for which we suggest the use of the corresponding pioneering localities: Burgess type for the early Palaeozoic black shales, Monte San Giorgio type for the Triassic black shales, Holzmaden type for the pyrite-rich black shales and Solnhofen type for platy limestones.

Nature Communications, Dec 6, 2023

Recently, on the basis of a single specimen (ROMIP 64897) from the Royal Ontario Museum (Canada),... more Recently, on the basis of a single specimen (ROMIP 64897) from the Royal Ontario Museum (Canada), Whalen and Landman 1 described the new coleoid taxon with a fairly completely preserved frontal part as Syllipsimopodi bideni. The specimen, recovered from the Bear Gulch Limestone, Heath Formation in Fergus County, Montana, USA, is of Serpukhovian age 2 . Based on the suggested presence of a gladius, ten arms, and fins, as well as the supposed absence of a phragmocone, the authors interpreted the "remarkably well-preserved" specimen as "the oldest definitive vampyropod and crown coleoid" 1 . We herein test if the fidelity of preserved characters in S. bideni affects the interpretation of this organism-particularly by comparing these characters to other soft bodied cephalopod fossils from Bear Gulch. We provide evidence for the likely synonymy of S. bideni and Gordoniconus beargulchensis. Our interpretation casts doubt on the phylogeny proposed by Whalen and Landman 1 , who suggested S. bideni as the oldest vamyropod. Vampyropoda ( = Octobrachia or Octopodiformes) is considered to be the sister group of all tenarmed cephalopods (Decabrachia) , which is also supported by recent molecular analyses . The holotypes of the early coleoids Gordoniconus beargulchensis 9 and Syllipsimopodi bideni share many important morphological characters. They are both of the same age and come from the same locality. In our Fig. , we show the photographs of both holotypes (Fig. ) and line drawings made after these published images (Fig. ) at the same scale. In Fig. , we overlaid the line drawings of both holotypes with the drawing of G. beargulchensis being scaled down by 20% to fit the body chamber width to each other. This overlay demonstrates that the morphology and proportions of the preserved parts of the two holotypes are so similar that we consider S. bideni may be a 1234567890():,; 1234567890():,;

Fossil Record, Dec 17, 2021

Supplementary material from "Was the Devonian placoderm Titanichthys a suspension feeder?

Large nektonic suspension feeders have evolved multiple times. The apparent trend among apex pred... more Large nektonic suspension feeders have evolved multiple times. The apparent trend among apex predators for some evolving into feeding on small zooplankton is of interest for understanding the associated shifts in anatomy and behaviour, while the spatial and temporal distribution gives clues to an inherent relationship with ocean primary productivity and how past and future perturbations to these may impact on the different tiers of the food web. The evolution of large nektonic suspension feeders— 'gentle giants'—occurred four times among chondrichthyan fishes (e.g. whale sharks, basking sharks and manta rays), as well as in baleen whales (mysticetes), the Mesozoic pachycormid fishes and at least twice in radiodontan stem group arthropods (Anomalocaridids) during the Cambrian Explosion. The Late Devonian placoderm Titanichthys has tentatively been considered to have been a megaplanktivore, primarily due to its gigantic size and narrow, edentulous jaws while no suspension-feeding apparatus have ever been reported. Here, the potential for microphagy and other feeding behaviours in Titanichthys is assessed via a comparative study of jaw mechanics in Titanichthys and other placoderms with presumably differing feeding habits (macrophagy and durophagy). Finite-element models of the lower jaws of Titanichthys termieri in comparison to Dunkleosteus terrelli and Tafilalichthys lavocati reveal considerably less resistance to von Mises stress in this taxon. Comparisons with a selection of large-bodied extant taxa of similar ecological diversity reveal similar disparities in jaw stress resistance. Our results, therefore, conform to the hypothesis that Titanichthys was a suspension feeder with jaws ill-suited for biting and crushing but well suited for gaping ram feeding.

Acta Palaeontologica Polonica, 2001

New records of nautiloid beak elements conventionally classified as "Rhyncholithes hirundo (Bigue... more New records of nautiloid beak elements conventionally classified as "Rhyncholithes hirundo (Biguet, 1819)" and "Conchorhynchus avirostris (von Schlotheim, 1820)" with carbonised (originally chitinous) three-dimensionally preserved appendages from the Upper Muschelkalk (Middle Triassic) of northern Württemberg (Southwest Germany) enable restoration of the complete beak of Germanonautilus. In three specimens, the lower mandible is embedded within the living chamber of Germanonautilus conchs. Beak elements of Germanonautilus differ from those of Recent Nautilus in the more elongate appendages of the fossil lower mandibles and the weaker sculpture on the originally chitinous parts. Furthermore, the dorsal sculpture of the fossil conchorhynchs consists of ridges rather than denticles and the ventral sculpture of the fossil rhyncholiths displays ridges in places where the Recent rhyncholiths have a smooth surface. Additionally, the fossil beak elements attained a larger size than their Recent counterparts. During transport of "Rhyncholithes hirundo", the light chitinous parts served as a sail and the heavier conchorhynch anchored in the sediment causing alignment. In contrast to the irregularly embedded isolated rhyncholiths, the conchorhynchs usually settled with their ventral side up. From the study of 407 fossil nautiloid beak-elements, a significant variability of the hard parts is evident. Consequently, the assignment of specific morphologies to the species of Germanonautilus is impossible.

Conch Form Analysis, Variability, Morphological Disparity, and Mode of Life of the Frasnian (Late Devonian) Ammonoid Manticoceras from Coumiac (Montagne Noire, France)

Springer eBooks, 2007

Intraspecific variation of conch shape has been documented for many Mesozoic ammonoids (eg, Aguir... more Intraspecific variation of conch shape has been documented for many Mesozoic ammonoids (eg, Aguirre-Urreta, 1998; Bhaumik et al., 1993; Dagys and Weitschat, 1993a, b; Mitta, 1990; Tanabe, 1993), while Paleozoic ammonoids are commonly regarded as expressing much less variability. Traditionally, species concepts which were applied on Devonian ammonoids were strictly typological and based on the holotype and few paratypes. The investigation of larger populations was only rarely achieved (cf. Dzik, 1985 for Mesozoic ammonoids). ...

Varioevodevo: Intraspecific Variation in Paleozoic Ammonoids

GSA Annual Meeting in Indianapolis, Indiana, USA - 2018, 2018

Devonian (Emsian, Givetian) blastoids and crinoids from the Tafilalt, Morocco

Neues Jahrbuch für Geologie und Paläontologie, Nov 1, 2018

Two Emsian species of crinoids, Kroppocrinus garamdouaraensis n. sp. and Elicrinus? weyeri, and t... more Two Emsian species of crinoids, Kroppocrinus garamdouaraensis n. sp. and Elicrinus? weyeri, and two species of blastoids, Pentremitidea pailleti (Emsian) and Hyperoblastus clavatus (Givetian), are described herein from the Tafilalt of Morocco. The crinoid records expand the sparse record of Devonian crinoids within Morocco; the blastoids represent the first report of this class from the Anti-Atlas and probably northern Africa. Key words: Crinoidea, Blastoidea, Emsian, Givetian, Anti-Atlas, Tafilalt.

Editorial: Jobst Wendt, the northern African Devonian sediments and their carbonate build-ups

Neues Jahrbuch für Geologie und Paläontologie, Nov 1, 2018

JOBST WENDT spent much of his career as a sedimentologist and palaeontologist carrying out resear... more JOBST WENDT spent much of his career as a sedimentologist and palaeontologist carrying out research on Devonian to Jurassic sedimentary successions in Europe, northern Africa and Iran. This volume comprises articles on the palaeontology and sedimentology of the famous mudmounds of Hamar Laghdad (Morocco) and is dedicated to JOBS WENDT. Key words: Devonian, Carboniferous, Triassic, Jurassic, Algeria, Italy, Morocco, sedimentology, palaeontology.

Patterns of Intraspecific Variation in Cephalopods - New Data from 3D Morphometry of Nautilus Shells

GSA Annual Meeting in Seattle, Washington, USA - 2017, 2017

Cephalopod Associations, Alpha Diversity and Paleoecology of the Cretaceous in the Alpstein, Switzerland

GSA Annual Meeting in Denver, Colorado, USA - 2016, 2016

PeerJ, Dec 21, 2022

Fossil chondrichthyan remains are mostly known from their teeth, scales or fin spines only, where... more Fossil chondrichthyan remains are mostly known from their teeth, scales or fin spines only, whereas their cartilaginous endoskeletons require exceptional preservational conditions to become fossilized. While most cartilaginous remains of Famennian (Late Devonian) chondrichthyans were found in older layers of the eastern Anti-Atlas, such fossils were unknown from the Hangenberg black shale (HBS) and only a few chondrichthyan teeth had been found therein previously. Here, we describe a Meckel's cartilage from the Hangenberg black shale in Morocco, which is the first fossil cartilage from these strata. Since no teeth or other skeletal elements have been found in articulation, we used elliptical Fourier (EFA), principal component (PCA), and hierarchical cluster (HCA) analyses to morphologically compare it with 41 chondrichthyan taxa of different size and age and to evaluate its possible systematic affiliation. PCA and HCA position the new specimen closest to some acanthodian and elasmobranch jaws. Accordingly, a holocephalan origin was excluded. The jaw shape as well as the presence of a polygonal pattern, typical for tessellated calcified cartilage, suggest a ctenacanth origin and we assigned the new HBS Meckel's cartilage to the order Ctenacanthiformes with reservations.

Fossil Record, Feb 1, 2006

A late Vise ´an section of clastic and carbonatic rocks is described from the eastern part of the... more A late Vise ´an section of clastic and carbonatic rocks is described from the eastern part of the Anti-Atlas (Morocco). The sedimentary succession is a mixed carbonate-siliciclastic system influenced by sea-level fluctuations. The sedimentology of the section is interpreted with respect to transgressive-regressive cycles and systems tracts. Highstand sediments yielded ammonoid assemblages from six horizons; a total of 1,040 specimens separated into 20 species are described in the palaeontological section. The genus Itimaites is new, together with the 16 new species Itimaites parabolicus n.

Scientific Reports, Feb 18, 2020

Reproductive strategies of extinct organisms can only be recognised indirectly and hence, they ar... more Reproductive strategies of extinct organisms can only be recognised indirectly and hence, they are exceedingly rarely reported and tend to be speculative. Here, we present a mass-occurrence with common preservation of pairs of late Givetian (Middle Devonian) oncocerid cephalopods from Hamar Laghdad in the Tafilalt (eastern Anti-Atlas, Morocco). We analysed their spatial occurrences with spatial point pattern analysis techniques and Monte carlo simulations; our results shows that the pairwise clustering is significant, while ammonoids on the same bedding plane reveal a more random distribution. it is possible that processes such as catastrophic mass mortality or post-mortem transport could have produced the pattern. However, we suggest that it is more likely that the oncocerids were semelparous and died shortly after mating. These findings shed new light on the variation and evolution of reproductive strategies in fossil cephalopods and emphasise that they cannot be based on comparisons with extant taxa without question. Among the two major clades of living cephalopods, the Coleoidea and Nautiloidea, there is a broad range of reproductive strategies. Coleoids were long considered to be invariably semelparous (reproducing only once), while Nautilus is iteroparous (giving rise to offspring multiple times) 1 . However, in recent years, squid, octopus and cuttlefish were shown to exhibit a wide range of reproductive strategies and life cycles 2 . Nevertheless, although its reproductive biology is still poorly known, Nautilus is unique among living cephalopods in its polycyclic spawning and long life span, in contrast to the monocyclic spawning (which can occur in separate batches or during an extended time period) of the relatively short-lived coleoids 1,2 . Studies of the reproduction strategies of the mostly externally shelled fossil cephalopods are very rare, largely because the scarcity of soft part preservation strongly limits the possibilities of these investigations. Yet, cephalopods such as ammonoids, bactritids and orthocerids possess small protoconchs and thus eggs and hatchlings; accordingly, they are often considered to be close to coleoids in their reproductive strategy, while cephalopods with large embryonic shells are generally considered to be closer to the living Nautilus 3-6 . In addition, nautiloids are usually thought to be K-strategists (type I survivorship), while coleoids, ammonoids, bactritids and partly orthocerids are seen as r-strategists (type III survivorship 3,7 ). However, since both K-and r-strategies occur among recent coleoids combined with a semelparous life cycle 2 , these assumptions may be too simple. In addition, the paradigm of K-and r-strategy 8 has been abandoned in the field of life-history evolution for some time . Previous studies have focused on life history traits that can be assessed with some reliability. For example, the mode of life of hatchlings can be inferred from the size of the embryonic shell and facies distribution, while the relative size of the hatchling to the adult can be informative about fecundity . Iteroparity or semelparity is more difficult to identify in fossil cephalopods as direct evidence is lacking. In some cases, it has been inferred from combinations of the aforementioned life history traits ; however, these may not always be good predictors. Apparent mass spawning events in the Late Devonian ammonoid Prolobites were seen as support for their similarity to coleoids in terms of reproduction . Further mass occurrences of several ammonoid species in the Middle Carboniferous of Arkansas were similarly interpreted as support for semelparity 14 . In another case, ovoviviparity,

Lithology Controls Ammonoid Size Distributions

PALAIOS, Dec 29, 2022

ABSTRACT Body-size distributions of organisms across environments in space and time are a powerfu... more ABSTRACT Body-size distributions of organisms across environments in space and time are a powerful source of information on ecological and evolutionary processes. However, most studies only focus on selected parameters of size distributions (e.g., central tendency or extremes) and rarely take into account entire distributions and how they are affected by the collection style and facies. Here we analyze the impact of facies, region, taxonomy, and collection style over size distributions using diameter as a proxy of Late Devonian ammonoids in their entirety using non-metric multidimensional scaling and PERMANOVA based on Kolmogorov distance. The effects are then compared with effects on mean sizes. In all analyses, lithology was the dominant effect, with sizes greater by 59% in marls and by 33% in limestones, as compared to black shales. The effect of complete sampling style was a decrease in size by 11%. Kurtosis was an important parameter differentiating size distributions, with platykurtic distributions in marls and leptokurtic distributions in limestones, suggesting that this parameter may reflect different degrees of time averaging. Most size distributions were positively skewed, but most strongly in marls. Complete sampling led to skewness values close to zero (symmetrical distributions) and high kurtosis. Samples from higher paleolatitudes were on average smaller, but contained outliers with the largest sizes, highlighting the need to analyze entire distributions. Lithology and collection differences need to be accounted for when evaluating size differences across space (polar gigantism) and time (Lilliput effect). Similarly, differences in facies may affect species determination.

Swiss Journal of Palaeontology, Jul 25, 2017

Mimosphinctes is an ammonoid genus that occurs in many localities that formerly surrounded the Pr... more Mimosphinctes is an ammonoid genus that occurs in many localities that formerly surrounded the Prototethys. In spite of the great exposures and abundance of fossils, unequivocal and well-documented records of this genus from Gondwana were missing. Here, a recently discovered specimen from the eastern Anti-Atlas of Morocco is described and the taxon Mimosphinctes karltschanzi n. sp. is introduced. Based on this discovery, the state of the art of ammonoid stratigraphy in the eastern Anti-Atlas is shortly discussed with a focus on the timing of the Daleje Event.

Fossil Record, Mar 20, 2018

Selected specimens from the Jurassic ammonoid family Arietitidae were investigated using morphome... more Selected specimens from the Jurassic ammonoid family Arietitidae were investigated using morphometric methods of transverse and longitudinal conch section analysis. The family Arietitidae is characterized by similarities in the conch geometry, but variation can be demonstrated by means of differences in conch morphology. Our study focuses on a specimen of the arietitid Pararnioceras sp., which revealed striking changes in conch morphology due to a syn vivo growth through a parasitic serpulid. Changes in its ontogenetic development are compared with specimens without epizoans. The ecological interpretation of the morphometric data allows the conclusion that the host possessed the ability to counteract the parasitic conch abnormalities by adapting its housing growth, thus ensuring survival. MB.C.27408 (formerly Technical University Berlin Coll.), Coroniceras sp. from the Heinemann claypit near Oelber am weißen Wege: 18-96 mm conch diameter (Fig. ).

Swiss Journal of Palaeontology, Nov 1, 2019

Here, we describe part of a large-bodied macrophagous plesiosaur jaw from the lower Bajocian (Mid... more Here, we describe part of a large-bodied macrophagous plesiosaur jaw from the lower Bajocian (Middle Jurassic) Passwang Formation near Arisdorf in the Basel-Land canton of Switzerland. The specimen preserves the posterior glenoid extremity of the right mandibular ramus comprising the surangular, angular, articular, and probably the prearticular. Notable character states include a transversely expanded surangular that incorporates a prominent medial ridge adjacent to the glenoid and a shallow dorsal fossa, together with a conspicuous trough extending across the lateral surfaces of both the surangular and angular; there is also a basally broad and medially deflected retroarticular process. Collectively, these features suggest affinities with Middle-Late Jurassic pliosaurids, as well as some coeval rhomaleosaurids. Based on such comparisons, we estimate that the Passwang Formation mandible was approximately 1.5 m long when complete, and thus approaches the size range of the largest-known pliosaurids. This discovery supplements the sparse record of diagnostic pliosaurid-like remains from Switzerland and contributes to the currently incomplete knowledge of pre-Callovian Middle Jurassic plesiosaurs globally.

Swiss journal of palaeontology, May 30, 2024

Swiss journal of palaeontology, Mar 4, 2024

Nature Communications, Dec 6, 2023

Fossil Record, Dec 17, 2021

Supplementary material from "Was the Devonian placoderm Titanichthys a suspension feeder?

Acta Palaeontologica Polonica, 2001

Conch Form Analysis, Variability, Morphological Disparity, and Mode of Life of the Frasnian (Late Devonian) Ammonoid Manticoceras from Coumiac (Montagne Noire, France)

Springer eBooks, 2007

Varioevodevo: Intraspecific Variation in Paleozoic Ammonoids

GSA Annual Meeting in Indianapolis, Indiana, USA - 2018, 2018

Devonian (Emsian, Givetian) blastoids and crinoids from the Tafilalt, Morocco

Neues Jahrbuch für Geologie und Paläontologie, Nov 1, 2018

Editorial: Jobst Wendt, the northern African Devonian sediments and their carbonate build-ups

Neues Jahrbuch für Geologie und Paläontologie, Nov 1, 2018

Patterns of Intraspecific Variation in Cephalopods - New Data from 3D Morphometry of Nautilus Shells

GSA Annual Meeting in Seattle, Washington, USA - 2017, 2017

Cephalopod Associations, Alpha Diversity and Paleoecology of the Cretaceous in the Alpstein, Switzerland

GSA Annual Meeting in Denver, Colorado, USA - 2016, 2016

PeerJ, Dec 21, 2022

Fossil Record, Feb 1, 2006

Scientific Reports, Feb 18, 2020

Lithology Controls Ammonoid Size Distributions

PALAIOS, Dec 29, 2022

Swiss Journal of Palaeontology, Jul 25, 2017

Fossil Record, Mar 20, 2018

Swiss Journal of Palaeontology, Nov 1, 2019