[Paleontology • 2024] The Marine Conservation Deposits of Monte San Giorgio (Switzerland & Italy): the Prototype of Triassic Black Shale Lagerstätten

 

The marine conservation deposits of Monte San Giorgio (Switzerland, Italy): the prototype of Triassic black shale Lagerstätten.

in Klug, Spiekman, Bastiaans, Scheffold et Scheyer, 2024.

 DOI: 10.1186/s13358-024-00308-7 

Abstract

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.

Keywords: Konservat-Lagerstätten, Taphonomy, Marine reptiles, Exceptional preservation

Three important marine reptiles from the Middle Triassic of Monte San Giorgio with their reconstructions, recently crafted by Beat Scheffold. 

A Tanystropheus, PIMUZ T 2817. B Cyamodus, PIMUZ T58. C, Mixosaurus, PIMUZ T 4923 (top) and PIMUZ T 4376 (bottom)

Fossilized foetuses inside the mother, examples from the Middle Triassic of Monte San Giorgio. A Mixosaurus, PIMUZ T 4830 (e.g., Brinkmann, 1996; Miedema et al., 2023). B Saurichthys, PIMUZ T 3917 (e.g., Maxwell et al., 2018)

Fossilized mollusks from the Middle Triassic of Monte San Giorgio (see Rieber, 1969, 1970, 1973; Pieroni, 2022). 

A, Proarcestes extralabiatus, internal mould. B, Repossia acutenodosa, silicified internal mould. C, Proarcestes extralabiatus, external mould. D, Phragmoteuthis ticinensis with complete arm crown, cephalic cartilage, oesophagus and ink sac. E, Daonella caudata. F, Pleuronautilus sp., internal mould

Some animals from Monte San Giorgio.
 Note that not all of the depicted taxa may have co-occurred in time or in space (habitat depth, etc.). At Monte San Giorgio, the water depth was likely greater then shown in these images.
A Meride Limestone (Ladinian). B Besano Formation (Anisian)

Reconstructions by Beat Scheffold.  

Conclusions: 

The conservation deposits of Anisian and Ladinian age of Monte San Giorgio, comprising the Besano Formation, Cava inferiore, Cava superiore, Cassina Beds, and the Kalkschieferzone, represent some of the first black shale conservation deposits of Triassic age that were thoroughly studied. Now, after a century of excavations and more than a century of research, these deposits begin to enjoy global scientific recognition (e.g., Etter, 2002a; Rieppel, 2019), and continue to produce valuable new information about the palaeobiology and evolution of Triassic vertebrates today.

With this paper, we want to highlight the key role of the conservation deposits of Monte San Giorgio: comparable to the pioneer role of the Burgess Shale for the Cambrian Lagerstätten or Solnhofen for the Mesozoic platy limestones, we highlight the pioneer role of the Besano Formation in particular as the prototype for Triassic Lagerstätten. Our simple comparison of 45 Fossillagerstätten worldwide employing principal component and hierarchical cluster analyses of 32 traits based on the ...

Christian Klug, Stephan N. F. Spiekman, Dylan Bastiaans, Beat Scheffold and Torsten M. Scheyer. 2024. The Marine Conservation Deposits of Monte San Giorgio (Switzerland, Italy): the Prototype of Triassic Black Shale Lagerstätten.  Swiss Journal of Palaeontology. 143, 11. DOI: doi.org/10.1186/s13358-024-00308-7 

 

[Paleontology • 2024] Postcranial Anatomy of Besanosaurus leptorhynchus (Reptilia: Ichthyosauria) from the Middle Triassic Besano Formation of Monte San Giorgio (Italy/Switzerland), with Implications for Reconstructing the Swimming Styles of Triassic Ichthyosaurs

Besanosaurus leptorhynchus Dal Sasso & Pinna, 1996
Artistic reconstruction (based on BES SC 999) catching a Phragmoteuthis. 

in Bindellini, Wolniewicz, Miedema, Dal Sasso et Scheyer, 2024.

DOI: 10.1186/s13358-024-00330-9 

 x.com/ASWolniewicz

 Artwork by Alessio Ciaffi

Abstract

Besanosaurus leptorhynchus Dal Sasso & Pinna, 1996 was originally described on the basis of a single complete fossil specimen excavated near Besano (Italy). However, a recent taxonomic revision and re-examination of the cranial osteology allowed for the assignment of five additional specimens to the taxon. Here, we analyse, describe and discuss the postcranial anatomy of Besanosaurus leptorhynchus in detail. The size of the specimens examined herein ranged from slightly more than one meter to eight meters. Overall, several diagnostic character states for this taxon are proposed, demonstrating a mosaic of plesiomorphic and derived features. This is best exemplified by the limbs, which show very rounded elements in the forelimbs, and pedal phalanges with retained rudimentary shafts. We suggest that the widely spaced phalanges in the forefins of Besanosaurus leptorhynchus were embedded in a fibrocartilage-rich connective tissue, like in modern cetaceans. We also review the similarities of Besanosaurus with Pessopteryx and Pessosaurus, allowing us to conclude that Besanosaurus is not a junior synonym of either of the two taxa. Lastly, to test the swimming capabilities of Besanosaurus leptorhynchus, we expanded on a previously published study focussing on reconstructing the swimming styles of ichthyosaurs. Besanosaurus leptorhynchus was found to possess a peculiar locomotory mode, somewhat intermediate between anguilliform swimmers, such as Cymbospondylus and Utatsusaurus, and some shastasaur-grade (e.g., Guizhouichthyosaurus) and early-diverging euichthyosaurian (e.g., Californosaurus) ichthyosaurs. Based on our results, we furthermore suggest that mixosaurids acquired their characteristic body profile (dorsal fin and forefins that are distinctly enlarged compared to the hindfins) independently and convergently to the one that later appeared in Parvipelvia. Moreover, the different swimming styles inferred for Cymbospondylus, Mixosauridae, and Besanosaurus strengthen the earlier hypothesis of niche partitioning among these three distinct ichthyosaur taxa from the Besano Formation.

Keywords: Ichthyosauria, Shastasauridae, Middle Triassic, Besano Formation, Monte San Giorgio, Postcranial anatomy, Osteology, Phylogeny, Swimming style, Marine reptiles

Artistic reconstruction of Besanosaurus leptorhynchus (based on BES SC 999) catching a Phragmoteuthis. Two individuals of Mixosaurus and a shoal of the ammonoid Ceratites can be seen in the background to the left of Besanosaurus leptorhynchus. Some ammonoids of the genus Serpianites are visible swimming around the large ichthyosaur and a single individual of the same ammonoid is depicted in the foreground on the right, along with other specimens of Phragmoteuthis.

 Artwork by Alessio Ciaffi

 

Gabriele Bindellini, Andrzej S. Wolniewicz, Feiko Miedema, Cristiano Dal Sasso and Torsten M. Scheyer. 2024. Postcranial Anatomy of Besanosaurus leptorhynchus (Reptilia: Ichthyosauria) from the Middle Triassic Besano Formation of Monte San Giorgio (Italy/Switzerland), with Implications for Reconstructing the Swimming Styles of Triassic Ichthyosaurs. Swiss Journal of Palaeontology. 143: 32. DOI: doi.org/10.1186/s13358-024-00330-9

  x.com/ASWolniewicz/status/1833548304040317084

[PaleoIchthyology • 2022] Libys callolepis • The First Jurassic Coelacanth from Switzerland

 Libys callolepis 

Ferrante, Menkveld-Gfeller & Cavin, 2022

 

DOI: 10.1186/s13358-022-00257-z 

Researchgate.net/publication/363791599 

  twitter.com/Lionel_Cavin

Abstract

Coelacanths form a clade of sarcopterygian fish represented today by a single genus, Latimeria. The fossil record of the group, which dates back to the Early Devonian, is sparse. In Switzerland, only Triassic sites in the east and southeast of the country have yielded fossils of coelacanths. Here, we describe and study the very first coelacanth of the Jurassic period (Toarcian stage) from Switzerland. The unique specimen, represented by a sub-complete individual, possesses morphological characteristics allowing assignment to the genus Libys (e.g., sensory canals opening through a large groove crossed by pillars), a marine coelacanth previously known only in the Late Jurassic of Germany. Morphological characters are different enough from the type species, Libys polypterus, to erect a new species of Libys named Libys callolepis sp. nov. The presence of Libys callolepis sp. nov. in Lower Jurassic beds extends the stratigraphic range of the genus Libys by about 34 million years, but without increasing considerably its geographic distribution. Belonging to the modern family Latimeriidae, the occurrence of Libys callolepis sp. nov. heralds a long period, up to the present day, of coelacanth genera with very long stratigraphic range and reduced morphological disparity, which have earned them the nickname of ‘living fossils’.

Keywords: Sarcopterygii, Actinistia, Libys, New species, Mesozoic, Toarcian, Morphology

Skeleton of Libys callolepis sp. nov. on the part (holotype, NMBE 5034073).
 A Photos with osteological details: 1, denticles on the proximal fin rays of the caudal fin. 2, Postparietal shield with the otic sensory canal opening as a deep groove crossed by pillars (white arrowhead). 3, Posterior parietal and the supraorbitals with their pillars (white arrowhead). 4, Consolidated snout with the anterior opening for the rostral organ (white arrowhead). 5, Teeth on the prearticular. B Semi-interpretative line drawing of the specimen

Libys callolepis sp. nov.

Diagnosis: Libys species with the postparietal shield about half the length of the parietonasal shield (the parietonasal is then proportionally shorter than in the type species). The teeth covering the prearticular are very small, and rounded and smooth. Between 41–47 neural arches. Fin rays are slender than in the type species and then not expanded. The scales are strongly ornamented with irregularly sized and elongated round-to-ovoid ridges disposed along a longitudinal axis.

Etymology: From the ancient Greek καλός, kalós, (‘beautiful’, ‘nice’) and λεπίς, lepís, (‘scale’) in reference to the nicely ornamented scales of the species, which differentiates it from the type species.

Holotype and only known specimen: NMBE 5034072 and 5034073, a sub-complete specimen preserved in right lateral view as part and counterpart. Most of the bones, including the scales on the body, are preserved in anatomical position and only the bones of the cheek and the jaw are missing. The specimen is kept in the collections of the Natural History Museum Bern (Canton of Bern, Switzerland).

Horizon and type locality: Toarcian (Lower Jurassic), Creux de l’Ours section, locality of Les Pueys near the Teysachaux summit (Canton of Fribourg, Switzerland).

 

Skeleton of  Libys callolepis sp. nov. on the counterpart (holotype, NMBE 5034072).
A Photos with osteological details: 1, articular head of the scapulocoracoid. 2, Scales on the flank immediately beneath the first anterior dorsal fin. 3, Scales of the lateral line showing the ornamental pattern with the larger central tubercles (white arrowheads point, showed only on one scale). 4, Scales on the ventral flank from the pelvic to the anal fin. 5, Axial mesomere (white arrowhead) surrounded by some fin rays of the anal fin. 6, Axial mesomeres (white arrowhead) partially covered by sediment in the pelvic fin. B Semi-interpretative line drawing of the specimen

Christophe Ferrante, Ursula Menkveld-Gfeller and Lionel Cavin. 2022. The First Jurassic Coelacanth from Switzerland. Swiss Journal of Palaeontology. 141: 15. DOI: 10.1186/s13358-022-00257-z

 Researchgate.net/publication/363791599_The_first_Jurassic_coelacanth_from_Switzerland

  twitter.com/Lionel_Cavin/status/1575729513513684993

[Paleontology • 2023] Lorrainosaurus keileni • The Rise of Macropredatory Pliosaurids near the Early-Middle Jurassic Transition

 Lorrainosaurus keileni   

 in Sachs, Madzia, Thuy & Kear, 2023.

 DOI: 10.1038/s41598-023-43015-y 

 facebook.com/DanielMadzia

artwork: Joschua Knüppe

Abstract

The emergence of gigantic pliosaurid plesiosaurs reshaped the trophic structure of Mesozoic marine ecosystems, and established an  ~ 80 million-year (Ma) dynasty of macropredatory marine reptiles. However, the timescale of their ‘defining’ trait evolution is incompletely understood because the fossil record of gigantic pliosaurids is scarce prior to the late-Middle Jurassic (Callovian),  ~ 165.3 Ma. Here, we pinpoint the appearance of large body size and robust dentitions to early-Middle Jurassic (Bajocian) pliosaurids from northeastern France and Switzerland. These specimens include a new genus that sheds light on the nascent diversification of macropredatory pliosaurids occurring shortly after the Early-Middle Jurassic transition, around  ~ 171 Ma. Furthermore, our multivariate assessment of dental character states shows that the first gigantic pliosaurids occupied different morphospace from coeval large-bodied rhomaleosaurid plesiosaurs, which were dominant in the Early Jurassic but declined during the mid-Jurassic, possibly facilitating the radiation and subsequent ecomorph acme of pliosaurids. Finally, we posit that while the emergence of macropredatory pliosaurids was apparently coordinated with regional faunal turnover in the epeiric basins of Europe, it paralleled a globally protracted extinction of other higher trophic-level marine reptiles that was not completed until after the earliest-Late Jurassic,  ~ 161.5 Ma.

Skeletal remains of the holotype (MNHNL BU159) of Lorrainosaurus keileni.
(a) Reconstruction in lateral view showing recovered elements. (b) Tooth crown with root. (c) Posterior section of mandible in lateral view. (d) Glenoid section of mandible in articular view. (e) Complete mandible in ventral view. (f) Enlargement of the mandibular symphysis. (g) Coracoid in dorsal view.

  

Plesiosauria de Blainville, 1835 

Pliosauridae Seeley, 1874 

Thalassophonea Benson & Druckenmiller, 2014 

Lorrainosaurus gen. nov.

Etymology: Derived from ‘Lorraine’, for the type locality; and ‘σαῦρος’ (sauros), Greek for ‘reptile’.

Type species: Lorrainosaurus keileni (Godefroit, 1994) 

Type locality and stage: A temporary road cutting between Montois-la-Montagne and Sainte-Marie-aux-Chênes ~ 18 km northeast of Metz in Lorraine, northeastern France. These deposits form part of the Marnes de Gravelotte regional lithostratigraphical unit correlated with the upper Bajocian (mid-Middle Jurassic) Parkinsonia parkinsoni Zone.

Diagnosis: Large-bodied thalassophonean pliosaurid autapomorphically distinguished by a transversely broad, ‘wedge-shaped’ splenial contact that extends anteriorly to the level of the fourth mandibular alveolus. Lorrainosaurus keileni also displays a unique character state combination: (1) laterally expanded and posteriorly constricted ‘spatulate’ symphyseal section of the mandible bearing five to six alveoli; (2) lateral trough on the mandible anterior to the glenoid fossa; (3) a retroarticular process that is shorter than the glenoid fossa; (4) retroarticular process with posteroventrally oriented dorsoventral long axis and slightly posteromedially inflected mediolateral long axis; (5) wide posteromedial seperation of the coracoids; (6) posterolateral edge of the coracoid (cornu) projecting beyond the level of the glenoid fossa (Fig. 1).

 

 Sven Sachs, Daniel Madzia, Ben Thuy and Benjamin P. Kear. 2023. The Rise of Macropredatory Pliosaurids near the Early-Middle Jurassic Transition. Scientific Reports. 13: 17558. DOI: 10.1038/s41598-023-43015-y

  facebook.com/DanielMadzia/posts/10232169972497818

 

[PaleoMammalogy • 2022] First Records of extinct kentriodontid and squalodelphinid Dolphins from the Upper Marine Molasse (Burdigalian Age) of Switzerland and A Reappraisal of the Swiss Cetacean Fauna

 the dolphins from the Upper Marine Molasse chasing a group of eurhinodelphinids: Kentriodon (foreground), a squalodelphinid (background, left) and a physeterid (background, right).

in Aguirre-Fernández​, Jost & Hilfiker, 2022. 

DOI: 10.7717/peerj.13251

Life restoration by Jaime Chirinos.

Abstract 

The Swiss Upper Marine Molasse (OMM) documents a transgression event dated to around 21 to 17 million years in which dolphin and other vertebrate remains have been reported. We revised the whole cetacean (whales and dolphins) OMM assemblage available in main collections, focusing on the identification and interpretation of periotics (bone that contains the inner ear). Periotics are rare, but they provide the richest taxonomic information in the sample and hint to environmental associations. Micro-computerized tomography allowed the reconstruction of bony labyrinths for comparisons and environmental interpretations. Three families are represented by periotics: Kentriodontidae, Squalodelphinidae and Physeteridae. The cetacean taxonomic composition of the Swiss OMM reinforces biogeographical patterns reported for the Mediterranean and Paratethys during the Burdigalian at a regional scale and the Calvert cetacean fauna of the northwest Atlantic at oceanic scale.

Life restoration of the dolphins from the Upper Marine Molasse chasing a group of eurhinodelphinids: Kentriodon (foreground), a squalodelphinid (background, left) and a physeterid (background, right).

Artwork: Jaime Chirinos.

 

 

Gabriel Aguirre-Fernández​, Jürg Jost and Sarah Hilfiker. 2022. First Records of extinct kentriodontid and squalodelphinid Dolphins from the Upper Marine Molasse (Burdigalian Age) of Switzerland and A Reappraisal of the Swiss Cetacean Fauna. PeerJ. 10:e13251. DOI: 10.7717/peerj.13251

 sci-news.com/paleontology/upper-marine-molasse-cetaceans-10823.html

[Paleontology • 2022] Giant Late Triassic Ichthyosaurs from the Kössen Formation of the Swiss Alps and Their Paleobiological Implications

in Sander, Pérez de Villar, Furrer & Wintrich, 2022.

DOI: 10.1080/02724634.2021.2046017 

 twitter.com/DennisMHansen 

ABSTRACT

The Late Triassic was populated by the largest ichthyosaurs known to date, reaching lengths of over 20 m. Recent discoveries include the remains of giant ichthyosaurs from the Austroalpine nappes of the eastern Swiss Alps. The finds come from the lower two members of the Kössen Formation (late Norian to Rhaetian). The material consists of a very large tooth lacking most of the crown from the Rhaetian Schesaplana Member, a postcranial bone association of one very large vertebra and ten rib fragments also from the Schesaplana Member, and an association of seven very large vertebral centra from the upper Norian to lower Rhaetian Alplihorn Member. These associations represent the only published partial skeletons of large to giant ichthyosaurs younger than middle Norian. We compare the material with the two largest ichthyosaurs known from partial skeletons, Shonisaurus popularis (15 m) and Shastasaurus sikkanniensis (21 m) from the late Carnian (ca. 230 Ma) of Nevada and the middle Norian (ca. 218 Ma) of British Columbia, respectively. The incomplete tooth confirms that at least some giant ichthyosaurs had teeth. Based on their proportional differences, the two bone associations may represent two different taxa of Shastasaurus-like ichthyosaurs. The larger and geologically younger specimen may have been nearly the size of S. sikkanniensis, and the smaller that of S. popularis. These giant ichthyosaurs from the eastern Swiss Alps indicate that such ichthyosaurs also colonized the western Tethys. The finds also unequivocally document that giant ichthyosaurs persisted to the latest Triassic.

SYSTEMATIC PALEONTOLOGY

ICHTHYOSAURIA Blainville, 1835

ICHTHYOSAURIA indet.

Material—One very large tooth lacking most of the crown, PIMUZ A/III 670.

Horizon and Locality—Rhaetian Schesaplana Member, Kössen Formation from Gretji, from scree 900 m southwest of Chrachenhorn Mountain, Davos-Monstein, Canton Grisons, eastern Swiss Alps, Switzerland (coordinates 46.6850323N, 9.8036022E).

    

MERRIAMOSAURIA Motani, 1999

SHASTASAURIDAE Merriam, 1902 sensu Ji et al., 2016

Definition—The last common ancestor of Shastasaurus and Besanosaurus, and all its descendants (from Ji et al., 2016).

SHASTASAURIDAE sp. A

Material—Specimen PIMUZ A/III 744, associated partial skeleton (Fig. 3) consisting of a very large anterior or middle dorsal vertebral centrum (PIMUZ A/III 744a) and eight distally incomplete dorsal ribs and two rib fragments (PIMUZ A/III 744b-l). The centrum is strongly tectonically deformed in the transverse plane. The ribs also appear tectonically deformed.

Horizon and Locality—Rhaetian Schesaplana Member, Kössen Formation. East side of Fil da Stidier ridge, Corn da Tinizong Mountain, Filisur, Canton Grisons, eastern Swiss Alps, Switzerland (coordinates 46.6204533N, 9.6816551E).

P. Martin Sander, Pablo Romero Pérez de Villar, Heinz Furrer and Tanja Wintrich. 2022. Giant Late Triassic Ichthyosaurs from the Kössen Formation of the Swiss Alps and Their Paleobiological Implications. Journal of Vertebrate Paleontology. e2046017. DOI: 10.1080/02724634.2021.2046017

  twitter.com/DennisMHansen/status/1519628909725245440

Huge new ichthyosaur, one of the largest animals ever, uncovered high in the Alps

 phys.org/news/2022-04-huge-ichthyosaur-largest-animals-uncovered.html

[Paleontology • 2021] Cranial Anatomy of Besanosaurus leptorhynchus Dal Sasso & Pinna, 1996 (Reptilia: Ichthyosauria) from the Middle Triassic Besano Formation of Monte San Giorgio, Italy/Switzerland: Taxonomic and Palaeobiological Implications

Besanosaurus leptorhynchus Dal Sasso & Pinna, 1996

in Bindellini​, Wolniewicz, ... et Dal Sasso​, 2021. 

DOI: 10.7717/peerj.11179 

facebook.com/AndrzejWolniewicz14 

Abstract 

Besanosaurus leptorhynchus Dal Sasso & Pinna, 1996 was described on the basis of a single fossil excavated near Besano (Italy) nearly three decades ago. Here, we re-examine its cranial osteology and assign five additional specimens to B. leptorhynchus, four of which were so far undescribed. All of the referred specimens were collected from the Middle Triassic outcrops of the Monte San Giorgio area (Italy/Switzerland) and are housed in various museum collections in Europe. The revised diagnosis of the taxon includes the following combination of cranial characters: extreme longirostry; an elongate frontal not participating in the supratemporal fenestra; a prominent ‘triangular process’ of the quadrate; a caudoventral exposure of the postorbital on the skull roof; a prominent coronoid (preglenoid) process of the surangular; tiny conical teeth with coarsely-striated crown surfaces and deeply-grooved roots; mesial maxillary teeth set in sockets; distal maxillary teeth set in a short groove. All these characters are shared with the holotype of Mikadocephalus gracilirostris Maisch & Matzke, 1997, which we consider as a junior synonym of B. leptorhynchus. An updated phylogenetic analysis, which includes revised scores for B. leptorhynchus and several other shastasaurids, recovers B. leptorhynchus as a basal merriamosaurian, but it is unclear if Shastasauridae form a clade, or represent a paraphyletic group. The inferred body length of the examined specimens ranges from 1 m to about 8 m. The extreme longirostry suggests that B. leptorhynchus primarily fed on small and elusive prey, feeding lower in the food web than an apex predator: a novel ecological specialisation never reported before the Anisian in a large diapsid. This specialization might have triggered an increase of body size and helped to maintain low competition among the diverse ichthyosaur fauna of the Besano Formation.

Figure 3: The most complete skeletons of Besanosaurus leptorhynchus.  
 (A) PIMUZ T 1895; (B) BES SC 999; (C) PIMUZ T 4376 (with a Mixosaurus specimen above it); (D) PIMUZ T 4847.

Scale bars represent 50 cm.

Figure 4: Skull and mandible of Besanosaurus leptorhynchus holotype BES SC 999, and interpretative drawings.
 Grey dashed lines and grey labels indicate elements not visible on the surface, grey areas indicate background sediment, light grey areas indicate background bone.

 Scale bar represents 10 cm.

Figure 20: Cranial reconstruction of Besanosaurus leptorhynchus.
Articulated skull and mandible in (A) left rostrolateral, (B) caudal (occipital), (C) dorsal, (D) left lateral, and (E) ventral (palatal) view.

 Line drawings by Marco Auditore.

 Besanosaurus leptorhynchus Dal Sasso & Pinna, 1996

Conclusions: 

In general, the specimens here described preserve and represent a remarkably complete cranial anatomy, so that Besanosaurus leptorhynchus now is among the best-understood Middle Triassic Ichthyosaur taxa to date. Our revision of the skull morphology of this taxon clarified long-standing controversies regarding its cranial anatomy and the taxonomy of shastasaurids from Monte San Giorgio. Based on this rich fossil material, we have demonstrated that Mikadocephalus gracilirostris (GPIT 1793/1) is a junior synonym of Besanosaurus leptorhynchus, providing evidence to refute previous hypotheses (Maisch & Matzke, 1997a, 2000; Maisch, 2010) about the co-occurrence of two different shastasaurid taxa (Besanosaurus and Mikadocephalus) in the Besano Formation.

The six specimens here described represent a potential ontogenetic series covering a certain size range of mainly adult and potentially subadult specimens (Fig. 19), ordered by increasing size as follows: PIMUZ T 4376, PIMUZ T 1895, BES SC 999, BES SC 1016, GPIT 1793/1, PIMUZ T 4847. An allometric growth signal, yet to be fully tested, has also been detected. Other sources of intraspecific variation such as sexual dimorphism, cannot be ruled out, however, partly due to the limited dataset. Here we also report evidence that Besanosaurus was the largest Middle Triassic ichthyosaur taxon of the Western Tethys since we confidently estimate a fully adult size of about 8 m for specimen PIMUZ T 4847.

Besanosaurus possesses an extremely long, slender, and gracile snout, representing an ecological specialization never seen before the Anisian in a large sized (~8 m) diapsid. The diagnostic, prominent coronoid (preglenoid) process of the surangular and a large rugose area for the attachment of the mAMES allow to infer the presence of well-developed jaw closing muscles, which likely had an important functional role: we assume an efficient and fast jaw closing movement and hypothesize a snap-feeder-like hunting strategy, with a specific preference for small and elusive prey (such as coleoids and/or small fishes). Among the ichthyosaurian Besano-Monte San Giorgio Fauna (Cymbopondylus, mixosaurids, and Besanosaurus), different hunting strategies, demonstrated by different morphologies and dimensions of the rostra, should have led to the maintenance of low interspecific competition (i.e., niche partitioning). We also hypothesize that the specialization represented by a longirostrine morphology might have been driven by prey preference and the methods of prey capture. Mixosaurus and Cymbospondylus show almost a global distribution; on the contrary, Besanosaurus is known only from the Besano Formation (Italy and Switzerland). A wider distribution of this genus is expected (and supported by McGowan & Motani, 2003: 135–136): it seems unlikely to us that Besanosaurus would be represented only in the Alpine Tethys realm.

Last but not least, the importance of Besanosaurus is not only given by the completeness and remarkable preservation of its remains, and its ecological role, but also by the key phylogenetic position occupied by the taxon in the ichthyosaurian phylogeny: our analysis, performed with a matrix that includes around 90% of unambiguous scores for B. leptorhynchus and revised scores for other Triassic taxa, shows that this taxon represents the basalmost member of shastasaur-grade ichthyosaurs.

Gabriele Bindellini​, Andrzej S. Wolniewicz, Feiko Miedema, Torsten M. Scheyer and Cristiano Dal Sasso​. 2021. Cranial Anatomy of Besanosaurus leptorhynchus Dal Sasso & Pinna, 1996 (Reptilia: Ichthyosauria) from the Middle Triassic Besano Formation of Monte San Giorgio, Italy/Switzerland: Taxonomic and Palaeobiological Implications. PeerJ. 9:e11179. DOI: 10.7717/peerj.11179

 facebook.com/AndrzejWolniewicz14/posts/4165706186814712

 

[Paleontology • 2020] Jaws of A Large Belemnite and An Ammonite from the Aalenian (Middle Jurassic) of Switzerland

Jurassic belemnite jaws: Acrocoelites conoideus & Hibolithes semisulcatus.

in Klug, Etter, et al., 2020. 

 DOI: 10.1186/s13358-020-00207-7 

Reconstructions by Kenneth De Baets.

 twitter.com/djbirddanerd

Abstract
Although belemnite rostra can be quite abundant in Jurassic and Cretaceous strata, the record of belemnite jaws was limited to a few specimens from Germany and Russia. Here, we describe and figure three cephalopod jaws from the Middle Jurassic Opalinus Clay of northern Switzerland. Although flattened, the carbonaceous fossils display enough morphological information to rule out an ammonoid, nautiloid or octobrachian origin of the two larger jaws. Their similarities to belemnite jaws from Germany and Russia conforms with our interpretation of these specimens as belemnite jaws. Based on their rather large size, we tentatively assign these two jaws to the megateuthidid Acrocoelites conoideus. The third jaw is a rather small upper jaw of an ammonoid. Since Leioceras opalinum is by far the most common ammonite in this unit in northern Switzerland, we tentatively suggest that the upper jaw belongs to this species.

Keywords: Cephalopoda, Megateuthididae, Graphoceratidae, Mouthparts, Body size, Opalinus clay

Reconstructions of Jurassic belemnite jaws.
a–c Acrocoelites conoideus from the Swiss Aalenian.
d–f Hibolithes semisulcatus from the German Kimmeridgian, modified after Klug et al. (2010b); the inner lamella of the lower jaw was enlarged

Christian Klug, Walter Etter, René Hoffmann, Dirk Fuchs and Kenneth De Baets. 2020. Jaws of A Large Belemnite and An Ammonite from the Aalenian (Middle Jurassic) of Switzerland. Swiss Journal of Palaeontology. 139, 4. DOI: 10.1186/s13358-020-00207-7

twitter.com/djbirddanerd/status/1300415883744022530

[Paleontology • 2020] Schleitheimia schutzi • A derived Sauropodiform Dinosaur and other Sauropodomorph Material from the Late Triassic of Canton Schaffhausen, Switzerland

Schleitheimia schutzi

Rauhut, Holwerda & Furrer, 2020

 DOI: 10.1186/s00015-020-00360-8

Illustration: Beat Scheffold. 

Abstract

Although sauropodomorph dinosaurs have been known for a long time from the Late Triassic of central Europe, sauropodomorph diversity and faunal composition has remained controversial until today. Here we review sauropodomorph material from the Canton Schaffhausen, Switzerland. The material comes from three different but geographically close localities and represents at least three different taxa. Apart from the common genus Plateosaurus, the material includes remains of two different large, robustly built sauropodomorphs. One of these is described as a new taxon, Schleitheimia schutzi n. gen. et sp., on the basis of an unusual ilium and associated axial and appendicular material. Schleitheimia represents a derived basal sauropodiform and possibly the immediate outgroup to Sauropoda, and thus is the most derived sauropodomorph known from the Late Triassic of Europe. These results thus highlight the diversity of sauropodomorphs in the Late Triassic of central Europe and further indicate widespread sauropodomorph survival across the Triassic-Jurassic boundary.

Keywords: Late Triassic, Switzerland, Sauropodomorpha, Sauropod origins

Posterior cervical vertebra of Schleitheimia schutzi n. gen., n. sp., PIMUZ A/III 538. a, b left and right lateral views; c dorsal view; d anterior view; e posterior view; f ventral view.

aas, anterior articular surface; na, neural arch; ld, lateral depression; nc, neural canal; pap, parapophysis; vk, ventral keel; vlr, ventrolateral ridge. Scale bar equals 5 cm

Systematic palaeontology

Dinosauria OWEN, 1842.

Sauropodomorpha HUENE, 1932.

Sauropodiformes SERENO 2007 (sensu McPhee et al. 2014).

Schleitheimia n. gen.

Type species. Schleitheimia schutzi sp. nov.

Etymology. Genus name refers to the type locality at Schleitheim, Canton Schaffhausen, Switzerland.

Schleitheimia schutzi sp. nov.

Etymology. Species epithet honours the collector of the type material, Emil Schutz (1916–1974).

Holotype. PIMUZ A/III 550, partial right ilium.

Type locality and horizon. The type locality is Santierge (Fig. 1), a hill situated 900 m south of the church of Schleitheim in the Swiss Canton Schaffhausen (47° 44′ 30″ N, 8° 29′ 13″ S). The material, collected in the Bratelen Bonebed (“Rhät-Bonebed”), was most probably derived from the uppermost part of the ‚Zanclodonmergel‘(= Knollenmergel), now called Gruhalde Member of the Klettgau Formation, uppermost Norian (Jordan et al. 2016).

Diagnosis. The new taxon can be diagnosed by the following autapomorphies: medial brevis shelf of ilium developed as dorsoventrally broad, rounded ridge just below the mid-height of the iliac blade on the medial side that ends in a large, round expansion at the posterior end of the ilium; fourth trochanter of the femur very robust and arises gradually out of the posterior surface of the bone at about its mid-width towards its apex at the posteromedial margin; crista tibiofibularis of the femur exceptionally broad and only very slightly offset medially from the lateral margin of the shaft, so that no posteriorly facing shelf is present lateral to the crista.

Time-calibrated cladogram of basal sauropodomorph relationships (based on the unweighted analysis), showing the survival of numerous lineages (including sauropods) across the Triassic-Jurassic boundary

Conclusions: 

Fragmentary sauropodomorph remains from the probably Late Norian of Schaffhausen, Switzerland, that were long considered to represent the common central European genus Plateosaurus can be shown to represent a separate taxon of non-sauropodan sauropodomorphs, Schleitheimia schutzi. The recognition of this new taxon, together with an evaluation of other sauropodomorph material from the Late Triassic of Schaffhausen shows that at least three different basal sauropodomorph taxa were present in the Norian of Switzerland. Schleitheimia is a derived sauropodiform and might even represent the immediate outgroup to sauropods. In the context of a phylogenetic analysis, the new taxon indicates that the Triassic/Jurassic extinction event probably only had a minor effect on sauropodomorph evolution, and that the ascent of sauropods was delayed until the late Early Jurassic, when other basal sauropodomorph lineages perished in the Pliensbachian/Toarcian extinction event and gave way to an explosive radiation of that clade.

Oliver W. M. Rauhut, Femke M. Holwerda and Heinz Furrer. 2020. A derived Sauropodiform Dinosaur and other Sauropodomorph Material from the Late Triassic of Canton Schaffhausen, Switzerland.  Swiss Journal of Geosciences [Swiss J Geosci]. 113, 8.  DOI: 10.1186/s00015-020-00360-8

https://biologie-seite.de/News/Ein_fr%C3%BCher_Gigant_aus_der_Schweiz.html

[PaleoMammalogy • 2019] Cartierodon egerkingensis • A Large Hyaenodont from the Lutetian of Switzerland expands the Body Mass Range of the European Mammalian Predators during the Eocene

Cartierodon egerkingensis

Solé & Mennecart, 2019

DOI: 10.4202/app.00581.2018 

 naturalsciences.ch/organisations/swiss-systematics

We here present a new hyaenodont genus and species from the Lutetian locality of Egerkingen γ (Switzerland; MP13?): Cartierodon egerkingensis gen. et sp. nov. The new taxon is represented by numerous dental elements, mostly isolated teeth. The molars show typical features of a hypercarnivorous predator such as the strong reduction of the crushing (talonid/protocone) and puncturing (metaconid) structures. The calculation of several dental indices indicates that this hyaenodont may have been a bone-cracking predator. The new taxon differs from all the hyaenodonts previously known in Europe during the Ypresian and Lutetian by its larger size, with an estimated mass of almost 29 kg (the size of the extant African wild dog, Lycaon pictus). Other hyaenodonts known for this period do not exceed 20 kg. Previous authors proposed the hypothesis of an ecological limitation of the body mass, but the description of Cartierodon egerkingensis indicates instead that the European hyaenodonts continuously increased in size throughout the Eocene. We also performed a phylogenetic analysis in order to test the relationships of this new taxon: the new hyaenodont appears to be closely related to the Lutetian hyaenodont Prodissopsalis eocaenicus.

Key words: Mammalia, Hyaenodonta, Cartierodon, ecology, phylogeny, Eocene, Switzerland.

Hyaenodontid mammal Cartierodon egerkingensis gen. and sp. nov. from Switzerland, Egerkingen γ (MP13?, Lutetian, Eocene)

Systematic palaeontology 

Hyaenodonta Van Valen, 1967 

Hyaenodontoidea Leidy, 1869 

Hyaenodontidae Leidy, 1869 

Genus Cartierodon nov. 

Type species: Cartierodon egerkingensis sp. nov.; monotypic, see below. 

Etymology: Dedicated to Pastor Robert Cartier, who excavated the infilling of Egerkingen γ from 1840 to 1884 and gave his collection to the Naturhistorisches Museum Basel; combined with Greek odon, tooth. 

Cartierodon egerkingensis sp. nov.

Etymology: Refers to the type locality, the filling of Egerkingen γ. 

Holotype: NMB.Em.11, right mandible bearing p2, p3, p4, the trigonid of m1, and the alveoli of p1. 

Type locality: Egerkingen γ, Gaü, Solothurn, Switzerland. 

Type horizon: Unnamed unit of karst fillings in an aberrant siderolitic facies; MP13?, Lutetian, Eocene.

Diagnosis.— Differs from all contemporaneous European hyaenodont genera (Oxyaenoides, Proviverra, Cynohyaenodon, Eurotherium, Prodissopsalis, Leonhardtina, Allopterodon, Alienetherium, and Praecodens) by its larger size. It differs from Oxyaenoides by the presence of a metaconid on molars and transversally enlarged premolars. It also differs from Proviverra, Cynohyaenodon, Eurotherium, Leonhardtina, Allopterodon, Alienetherium, and Praecodens by a poorly developed metaconid on molars. It differs from Quer cytherium, with which it shares transversally enlarged premolars, by its larger size, poorly developed metaconid on molars, and less squared p2 and p3. It differs from Prodissopsalis eocaenicus, its closest hyaenodont relative, by a second foramen located below the anterior root of the p4, wider lower premolars, mesiodistally shorter talonid on m3, and a protocone area more developed on P3.

...

Taxonomy.— Modifications to the Borths and Stevens (2017b) matrix grouped almost all “proviverrine” taxa sensu Solé (2013) in the same clade (see below). However, hyaenodontines are still included in the “proviverrine” clade, as in previous analyses. This result refutes the monophyly of “Proviverrinae” sensu Solé (2013), resolving “proviverrines” as part of hyaenodontine stem lineages. Because our results agree with those of Borths et al. (2016), we propose to consider the Proviverrinae as a clade that includes the last common ancestor of Proviverra and Parvagula. We here propose to name Hyaenodontoidea the clade that includes the last common ancestor of Proviverra and Hyaenodon. This results in grouping Hyaenodontidae and Proviverrinae among Hyaenodontoidea.

Conclusions: 

The description of Cartierodon egerkingensis based on fossils from Egerkingen γ (MP13?) importantly improves our knowledge of the ecology of the Lutetian hyaenodonts. This taxon likely represents a bone-cracking hypercarnivore. Moreover, it is the largest hyaenodont from the Lutetian. 

Its body mass clearly shows that the maximum body mass of the European hyaenodontoids increased throughout the Ypresian and Lutetian, possibly in response to the vacated large-size predator niche after the disappearance of oxyaenids (Palaeonictis and Oxyaena) and mesonychids (Dissacus and Pachyaena) during the Ypresian. 

However, one can still wonder why European hyaenodonts did not reach 150 kg during the Eocene as some Pachyaena species did during the early Ypresian of Europe. This question needs future study, including the analysis of available prey body masses.

Floréal Solé and Bastien Mennecart. 2019. A Large Hyaenodont from the Lutetian of Switzerland expands the Body Mass Range of the European Mammalian Predators during the Eocene. Acta Palaeontologica Polonica. 64(2); 275-290. DOI: 10.4202/app.00581.2018 

naturalsciences.ch/organisations/swiss-systematics/new_species_swiss_made