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A new species of the metriorhynchid crocodylomorph Cricosaurus from the Upper Jurassic of southern Germany
Sachs, S., Young, M., Abel, P. & Mallison, H. (in press) A new species of the metriorhynchid crocodylomorph Cricosaurus from the Upper Jurassic of southern Germany. Acta Palaeontologica Polonica 64.
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Here we describe a new species of the metriorhynchid thalattosuchian Cricosaurus, C. bambergensis sp. nov., from the Upper Jurassic Torleite Formation of Wattendorf near Bamberg, Bavaria (southern Germany). The holotype and only known specimen is a nearly complete skeleton that shows a number of diagnostic traits including a bicarinate dentition formed by labiolingually compressed tooth crowns that lack a conspicuous enamel ornamentation and the presence of a distinct midline ridge with paired depressions on the palatines. Our phylogenetic analysis recovers a grouping of Cricosaurus bambergensis sp. nov. with C. elegans and C. suevicus. The implications of the new Cricosaurus species to the species complex from the late Kimmeridgian–early Tithonian of southern Germany is discussed. O
Sachs, Young, Abel, Mallison (2019) A ne
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Morphological and phylogenetic aspects of the dentition of Megacephalosaurus eulerti, a pliosaurid from the Turonian of Kansas, USA, with remarks on the cranial anatomy of the taxon

Madzia, D., Sachs, S. & Lindgren, J. (in press) Morphological and phylogenetic aspects of the dentition of Megacephalosaurus eulerti, a pliosaurid from the Turonian of Kansas, USA, with remarks on the cranial anatomy of the taxon. Geological Magazine. [Request a pdf]

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Megacephalosaurus eulerti is a large macropredatory plesiosaur representing one of the last members of the diverse pliosaurid clade Brachaucheninae. The taxon was established upon a nearly complete skull including the mandible and fragments of the postcranial skeleton originating from the lower middle Turonian (Upper Cretaceous) of Kansas, USA. Owing to its age, reasonable completeness and its state of preservation, M. eulerti bears important anatomical details regarding the last brachauchenines. Here we assess the dentition of the taxon, compare the teeth to those of other thalassophonean pliosaurids and comment on the utility of these results for inferences of the phylogenetic relationships of the last brachauchenines. Additionally, we provide remarks on the cranial anatomy of M. eulerti, revise character scores of this taxon used in current phylogenetic studies and address the phylogenetic relationships within Brachaucheninae. Parsimony analyses, aimed to test different character sampling and tree-search strategy, inferred only a single unambiguous synapomorphy uniting a clade formed by mid- to Late Cretaceous brachauchenines: presence of subcircular rather than subtrihedral/trihedral cross-sectional shape of the teeth. Still, the last brachauchenines (Brachauchenius and Megacephalosaurus) can be roughly characterized by a switch from anisodont to subisodont dentition and reduction of their tooth count. Nevertheless, the overall knowledge of the origin, phylogenetic relationships and distinguishability of brachauchenine pliosaurids remains poor and represents a subject for further extensive studies and modifications in taxon and character sampling.

2019


Filling the biostratigraphical gap: first choristoderan from the Lower–mid-Cretaceous interval of Europe

Reiss, S., Scheer, U., Sachs, S. & Kear, B.P. (2019) Filling the biostratigraphical gap: first choristoderan from the Lower–mid-Cretaceous interval of Europe. Cretaceous Research 96: 135-141. [Request a pdf]

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Choristodera is a clade of extinct aquatic reptiles whose fossils have been found in freshwater and marginal marine deposits from Europe, Asia and North America. The European record is the most extensive, spanning at least the Middle Jurassic to early Miocene, and incorporates the stratigraphically oldest and youngest members of the group. Despite this, there is an unexplained ∼70 myr gap in European choristoderan fossil occurrences. Here we fill this hiatus with the discovery of an isolated choristoderan dorsal vertebra from the lower Cenomanian ‘Rotkalk’ red limestone facies of the Essen Greensand Formation in Mülheim/Ruhr, North Rhine-Westphalia, western Germany. This specimen represents the first identifiable European choristoderan from the Kimmeridgian–Campanian interval, and displays a diagnostic state combination including an amphiplatyan centrum with synapophyses on the transverse processes that are level with the neurocentral suture. The palaeobiogeographical distribution of choristoderans thus likely transected the entire Laurasian landmass throughout the Cretaceous, with perceived stratigraphical interstices being a result of incomplete sampling.

2018


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A global perspective on Mesozoic marine amniotes
Sachs, S., Lindgren J. & Kear, B.P. (2018) A global perspective on Mesozoic marine amniotes. An Australasian Journal of Palaeontology 42(4): 457-460
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Mosasaurs are squamates that became the dominant predatory marine reptiles in the Late Cretaceous about 98–66 million years ago. Although early members of this group possessed body profiles similar to living terrestrial lizards, many of the later, more derived forms were streamlined and equipped with finlike limbs and a bilobed (hypocercal) tail fluke that would have enabled powerful swimming (Lindgren et al. 2010). Ecomorphological comparisons indicate that mosasaurs were probably very similar to modern pelagic sharks in terms of their hydrodynamic performance, and thus are convergent in both body form and locomotory style with other highly modified secondarily aquatic amniotes, including advanced ichthyosaurians (which were extremely specialised basallybranching non-saurian diapsids) and whales (Lindgren et al. 2011). Moreover, be
Sachs, Lindgren & Kear (2018) A global p
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Reassessment of the Styxosaurus snowii (Williston, 1890) holotype specimen and its implications for elasmosaurid plesiosaurian interrelationships

Sachs, S., Lindgren J. & Kear, B.P. (2018) Reassessment of the Styxosaurus snowii (Williston, 1890) holotype specimen and its implications for elasmosaurid plesiosaurian interrelationships. Alcheringa: An Australasian Journal of Palaeontology 42(4): 560-574. [Request a pdf]

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The holotype (KUVP 1301) of Styxosaurus snowii—one of the earliest described elasmosaurid plesiosaurians—consists of a well-preserved cranium, mandible and articulated sequence of anterior–mid-series cervical vertebrae found in the lowermost Campanian strata of the Smoky Hill Chalk Member in the Niobrara Formation of Kansas, USA. This particular specimen has proven important for recent phylogenies of Elasmosauridae, and is integral to resulting definitions of the subfamily-level clade, Styxosaurinae. Despite this, KUVP 1301 has not been redescribed or figured in detail since its original taxonomic establishment. We, therefore, re-evaluated KUVP 1301 and assessed its phylogenetic implications. Several notable character states are pertinent for diagnosing S. snowii at genus and species level: (1) an anisodont functional dentition comprising enlarged premaxillary and dentary teeth with a pair of maxillary ‘fangs’, and elongate posterior-most dentary teeth that overlap the upper tooth row; (2) a prominent dorsomedian crest extending from the tip of the premaxillary rostrum, and expanding into a low ‘mound-like’ boss between the external bony nasal openings and orbits; (3) a pronounced convex projection on the posterolateral edge of the squamosals; and (4) platycoelous post-axial cervical vertebral centra that are substantially longer than high, and bear both lateral longitudinal ridges and ventral notches. Character state comparisons with the congeneric subfamily specifier Styxosaurus browni suggest that taxonomic distinction is possible, but equivocal. We, therefore, restrict our definition of Styxosaurus to morphologies observable in KUVP 1301. Furthermore, phylogenetic analysis of our first-hand data returns inconsistent elasmosaurid intra-clade relationships, especially with regard to Styxosaurinae. Consequently, we posit that a more targeted reassessment of Elasmosauridae is necessary to resolve both species-level topologies and higher taxonomy within the group.

First evidence of a large predatory plesiosaurian from the Lower Cretaceous non-marine ‘Wealden facies’ deposits of northwestern Germany

Sachs, S., Hornung, J.J., Lallensack, J. & Kear, B.P. (2018) First evidence of a large predatory plesiosaurian from the Lower Cretaceous non-marine ‘Wealden facies’ deposits of northwestern Germany. Alcheringa: An Australasian Journal of Palaeontology 42(4): 501-508. [Request a pdf]

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Here, we describe the incomplete mandible of a large-skulled ‘pliosauromorph’ plesiosaurian from the Lower Cretaceous (Berriasian) of northwestern Germany. The fossil derives from limnic–brackish ‘Wealden facies’ deposits of the Deister Formation (Bückeberg Group), and is preserved as a natural mould in fine-grained sandstone. Examination of the original remains, in conjunction with a three-dimensional photogrammetrically digitized ‘cast’, revealed a conspicuous rosette of symphyseal alveoli, which would otherwise typically characterize Early–Middle Jurassic macrophagous plesiosaurians including rhomaleosaurids and the pliosaurid Simolestes. The Deister Formation ‘pliosauromorph’ represents the first record of a large-bodied plesiosaurian macrocarnivore from the ‘Wealden-facies’ strata of Europe, and thus adds a previously unrecognized trophic level of aquatic apex predators to the Early Cretaceous non-marine ecosystems of Europe.

A rare new Pliensbachian plesiosaurian from the Amaltheenton Formation of Bielefeld in northwestern Germany

Sachs, S. & Kear, B.P. (2018) A rare new Pliensbachian plesiosaurian from the Amaltheenton Formation of Bielefeld in northwestern Germany. Alcheringa: An Australasian Journal of Palaeontology 42(4): 487-500. [Request a pdf]

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We describe a new plesiosaurian from the upper Pliensbachian Amaltheenton Formation of Bielefeld in northwestern Germany. The taxon is based upon an incomplete associated skeleton comprising part of the right mandibular ramus, several teeth, a series of cervical, pectoral, dorsal and caudal vertebrae, as well as ribs, limb girdle elements including a nearly complete right scapula, and various distal limb bones. A unique character state combination serves to distinguish the Amaltheenton Formation remains from other previously documented Early Jurassic plesiosaurians. The most important features are the presence of a longitudinal notch incising the posterior rim of the glenoid fossa and retroarticular process, and a pronounced ventrolateral shelf on the scapula, both of which constitute derived states otherwise shared with Early Cretaceous leptocleidians. However, phylogenetic analysis using a ‘total group’ Plesiosauria data-set that specifically accommodates for Pliensbachian taxa unanimously placed the Amaltheenton Formation plesiosaurian among Early–Middle Jurassic pliosaurids. This discovery is significant because it reveals unexpected homoplasy, but also because it establishes what is only the third formally named plesiosaurian taxon thus far documented from Pliensbachian strata worldwide.

Soft-tissue evidence for homeothermy and crypsis in a Jurassic ichthyosaur

Lindgren, J., Sjövall, P., Thiel, V., Zheng, W., Ito, S., Wakamatsu, K., Hauff, R., Kear, B.P., Engdahl, A., Alwmark, C., Eriksson, M.E., Jarenmark, M., Sachs, S., Ahlberg, P.E., Marone, F., Kuriyama, T., Gustafsson, O., Malmberg, P., Thomen, A., Rodríguez-Meizoso, I., Uvdal, P., Ojika, M. & Schweitzer, M.H. (2018) Soft-tissue evidence for homeothermy and crypsis in a Jurassic ichthyosaur. Nature 564: 359–365. [Request a pdf]

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Ichthyosaurs are extinct marine reptiles that display a notable external similarity to modern toothed whales. Here we show that this resemblance is more than skin deep. We apply a multidisciplinary experimental approach to characterize the cellular and molecular composition of integumental tissues in an exceptionally preserved specimen of the Early Jurassic ichthyosaur Stenopterygius. Our analyses recovered still-flexible remnants of the original scaleless skin, which comprises morphologically distinct epidermal and dermal layers. These are underlain by insulating blubber that would have augmented streamlining, buoyancy and homeothermy. Additionally, we identify endogenous proteinaceous and lipid constituents, together with keratinocytes and branched melanophores that contain eumelanin pigment. Distributional variation of melanophores across the body suggests countershading, possibly enhanced by physiological adjustments of colour to enable photoprotection, concealment and/or thermoregulation. Convergence of ichthyosaurs with extant marine amniotes thus extends to the ultrastructural and molecular levels, reflecting the omnipresent constraints of their shared adaptation to pelagic life.

Not worth mentioning? Paleontological collections of small museums: the example of Bielefeld (North Rhine Westphalia, Germany).

Keiter, M. & Sachs, S. (2018) Not worth mentioning? Paleontological collections of small museums: the example of Bielefeld (North Rhine Westphalia, Germany). In: Beck, L.A., & Joger, U (eds.) Palaeontological collections of Germany, Austria and Switzerland. Springer, Berlin: 69-76. [Request a pdf]

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The Naturkunde-Museum in Bielefeld (Germany) is one of the smaller Museums of Nature in Germany, but it harbors a large collection of paleontological specimens. This collection mainly comprises material from the region, and as such is a valuable local archive for the history of life and environment. Among the highlights are several holotypes of Mesozoic vertebrates and invertebrates, a valuable assemblage of fossils from the Oligocene Doberg locality, as well as Pleistocene vertebrate material. It is any museum’s responsibility to take care of and develop such a historical heritage and convey its worth to the public.

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Thalattosuchian remains from the late Aalenian Eisensandstein Formation of Baden-Württemberg, southwestern Germany
Abel, P., Sachs, S. & Young, M. T. (2018) Thalattosuchian remains from the late Aalenian Eisensandstein Formation of Baden-Württemberg, southwestern Germany. Geobonn 2018, Abstracts: 223.
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The fossil record of marine reptiles from the Aalenian is globally poor. In Germany they are mostly limited to isolated and fragmentary remains, although at least one ichthyosaur, Stenopterygius aaleniensis, is known from a complete and articulated skeleton. The Aalenian thalattosuchian record has not yet been studied in detail, and a number of specimens are still undescribed. Among these unpublished fossils is cranial and postcranial material from the late Aalenian Eisensandstein Formation (“Dogger β”) of Baden-Württemberg (SW Germany) that is housed at the Staatliches Museum für Naturkunde Stuttgart. Despite their fragmentary nature, this material can be attributed to both major thalattosuchian subclades, Teleosauroidea and Metriorhynchoidea. The teleosauroid material includes five inco
Abel, Sachs & Young (2018) Thalattosuchi
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Einblicke in die Evolution der Thalattosuchier - Meereskrokodile des Mesozoikums
Young, M.T., Sachs, S. & Abel, P. (2018) Einblicke in die Evolution der Thalattosuchier - Meereskrokodile des Mesozoikums.
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Die Gruppe der Crocodylomorpha, die alle heutigen Krokodile und deren ausgestorbene Verwandte umfasst, hat eine lange, abwechslungsreiche Evolution hinter sich. Ihre ältesten Vertreter aus der Späten Trias (vor ca. 237 Millionen Jahren) waren noch reine Landbewohner, deren Körperbau eher Windhunden als heutigen Krokodilen glich.
Young, Sachs & Abel (2018) Einblicke in
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Mosasaurid and plesiosaurian remains from marginal facies of the lower Campanian (Upper Cretaceous) Bottrop and Vaals formations of western Germany

Sachs, S., Hornung, J. & Scheer, U. (2018) Mosasaurid and plesiosaurian remains from marginal facies of the lower Campanian (Upper Cretaceous) Bottrop and Vaals formations of western Germany. Cretaceous Research 87: 358-367. [Request a pdf]

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Isolated remains of mosasaurids and plesiosaurians are recorded from the lower Campanian Bottrop and Vaals formations of North Rhine-Westphalia, western Germany. A tooth crown from Bottrop- Fuhlenbrock, referred to an elasmosaurid plesiosaurian, represents the first record of this group from late-Upper Cretaceous strata of the area. Another presumed plesiosaurian remain is a fragmentary gastralium from Duisburg-Walsum. Some of the mosasaurid material from the Bottrop Formation (a tooth crown and vertebrae from Bottrop-Fuhlenbrock and Duisburg-Walsum) is assigned to the subfamily Plioplatecarpinae. The Vaals Formation, which is a lateral equivalent of the Bottrop Formation, yielded a single tooth crown, found at Aachen-Bildchen, that is here referred to the genus Hainosaurus. These finds from the Bottrop and Vaals formations constitute evidence of the presence of these taxa in proximal shelf to nearshore settings during the Campanian. The mosasaurid occurrences in particular may be an indicator that diversity and abundance increased in more basinward facies and greater palaeowaterdepth.

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Fossil Focus: Thalattosuchia
Young, M. T., Sachs, S. & Abel, P. (2018) Fossil Focus: Thalattosuchia. Palaeontology Online, 8 (5): 1-13 .
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To most people, crocodilians are large-bodied carnivores that have been unchanged since the age of the dinosaurs. However, during their 230 million-year history, modern crocodilians and their extinct relatives evolved a stunning diversity of body plans, with many looking very different from those alive today (crocodi les, alligators, caimans and gharials).
Young, M. T., Sachs, S. & Abel, P. (2018
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Arminisaurus schuberti – Ein neuer Plesiosaurier aus dem oberen Pliensbachium von Bielefeld und die Methoden seiner Konservierung
Sachs, S. & Keiter, M. (2018) Arminisaurus schuberti – Ein neuer Plesiosaurier aus dem oberen Pliensbachium von Bielefeld und die Methoden seiner Konservierung. Der Steinkern 32: 50-58.
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Verglichen mit den anderen Stufen des Unterjura sind Funde von Reptilien im Pliensbachium (182,7– 190,8 Mio. J.) eher selten (Sachs & Kear, 2017), weshalb ihre taxonomische Diversität für diesen Zeitabschnitt nur zum Teil bekannt ist. In der Literatur wird daher zuweilen von der “Pliensbachium-Lücke” gesprochen (Bardet et al., 2008). Dies gilt auch für die Gruppe der Plesiosaurier. Von diesen Meeresreptilien sind speziell aus dem nachfolgenden Toarcium eine große Zahl verschiedener Arten bekannt (Sachs et al., 2016; Vincent et al., 2017) und es liegen diverse, teils vollständige Skelette vor. Man denke etwa an die Funde aus der Region um Holzmaden (Hauff & Hauff, 1981) oder Whitby (Lomax, 2011). Aus dem Pliensbachium hingegen waren bisher nur zwei Arten bekannt: Westphaliasaurus simon
Sachs _ Keiter (2018) Arminisaurus schub
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Turonian marine amniotes from the Opole area in southwest Poland

Sachs, S., Jagt, J.W.M., Niedźwiedzki, R., Kędzierski, M., Jagt-Yazykova, E. & Kear, B.P. (2018) Turonian marine amniotes from the Opole area in southwest Poland. Cretaceous Research 84: 578-587. [Request a pdf]

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A few isolated plesiosaurian and mosasauroid squamate teeth were collected from the Opole area in southwest Poland during the late nineteenth century. Calcareous nannofossil analysis of their associated rock matrix indicates an early Turonian age (nannofossil zone UC7; Mytiloides ex gr. labiatus and Inoceramus apicalis inoceramid zones), which is significant because this constitutes a globally enigmatic interval of marine amniote evolution. The Opole plesiosaurian teeth are attributable to polycotylids, but an indeterminate mesopodial was also recovered. They are similar to specimens from the Cenomanian–Turonian in the Saxonian Cretaceous Basin of Germany and the Chalk succession of England, but differ from polycotylid remains found in the coeval Bohemian Cretaceous Basin of the Czech Republic, which are far more robust. The mosasaurid tooth crown from Opole compares favourably with dentary and maxillary teeth of a number of Turonian yaguarasaurines and basal russellosaurines, but in having well-developed carinae and a smooth labial and strongly folded/markedly striated lingual tooth surfaces it can be differentiated from taxa such as Yaguarasaurus columbianus (Colombia), Romeosaurus fumanensis and R. sorbinii (both Italy) and ‘Mosasaurus’ gracilis (England). However, a single record from the Bohemian Cretaceous Basin may refer to a conspecific form. All this suggests a potential for slight compositional differences between Cenomanian–Turonian marine amniote assemblages across central and northern Europe, although otherwise these regions probably constituted a common faunal belt bordering the Tethys Ocean.

2017


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The dentition of Megacephalosaurus eulerti (Plesiosauria, Pliosauridae) from the Turonian of Kansas and comments on the phylogenetic relationships of the last brachauchenines
Madzia, D., Sachs, S. & Lindgren, J. (2017) The dentition of Megacephalosaurus eulerti (Plesiosauria, Pliosauridae) from the Turonian of Kansas and comments on the phylogenetic relationships of the last brachauchenines. The Palaeontological Association, Abstracts of Annual Meeting, London: 93 .
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Megacephalosaurus eulerti was a large brachauchenine pliosaurid that roamed the Western Interior Seaway during the middle Turonian (Late Cretaceous). The type specimen (FHSM VP-321) consists of a nearly complete skull including the dentaries, and associated incomplete postcranial material. We assessed the dental morphology of Megacephalosaurus and the variability observed in its dentition. The results show that the dentition of M. eulerti was subisodont and subhomodont, with the most apparent differences observed in the development of the apicobasal ridges, which branch in some teeth. However, the taxonomic utility of this feature is debatable and perhaps depends on the part of the tooth cr
Madzia, Sachs _ Lindgren (2017) The dent
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Reste eines Elasmosauriers aus der Oberkreide von Schleswig-Holstein in der Sammlung des Naturkunde-Museums Bielefeld
Sachs, S. & Ladwig, J. (2017) Reste eines Elasmosauriers aus der Oberkreide von Schleswig-Holstein in der Sammlung des Naturkunde-Museums Bielefeld. Berichte Naturwissenschaftlicher Verein für Bielefeld und Umgegend 55: 28-36.
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Im Sommer 2016 erhielt das Naturkunde-Museum Bielefeld diverse Reste eines Elasmo-sauriers aus dem Obercampanium von Kronsmoor (Kreis Steinburg) in Schleswig-Holstein. Das Material umfasst fragmentarische Wirbel und Phalangen sowie nicht näher bestimmbare Fragmente. Weitere Teile des gleichen Skeletts (ein Zahn, Cervical-, Dorsal-und Caudalwirbel, Teile der Gliedmaßen und 110 Gastrolithen) befinden sich in der Sammlung des Geologischen Instituts der Universität Hamburg sowie in Privatsammlungen. In 2016, the Natural History Museum Bielefeld received fragmentary remains of an elasmosaurid plesiosaurian from the upper Campanian of Kronsmoor (Steinburg district) in Schleswig-Holstein (northern Germany). The material includes incomplete vertebrae, phalanges
Sachs _ Ladwig (2017) Reste eines Elasmo
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Reptilienfunde aus dem Muschelkalk von Gogolin

Sachs, S. & Hornung, J.J. (2017) Reptilienfunde aus dem Muschelkalk von Gogolin. In: Scheer, U. & Stottrop, U. (eds) Erdgeschichten Geologie im Ruhr Museum. Verlag der Buchhandlung Walther König, Essen: 140-141.

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Das Ruhr Museum besitzt in seinen Sammlungsbeständen einige Reptilienfunde aus dem Muschelkalk von Gogolin in Oberschlesien (heute Gmina Gogolin, Polen). Zu diesen gehört das hier gezeigte Kieferfragment, das die charakteristische abgeflachte und robuste Bezahnung der Placodontier aufweist, welche der Gruppe ihren deutschen Namen Pflasterzahnsaurier einbrachte. Placodontier waren im Wasser lebende Reptilien, deren kräftige Zähne dazu dienten die Schalen ihrer Nahrung zu knacken, die wahrscheinlich aus Muscheln und Armfüßern bestand (Neenan, 2014). Die flachen „Pflasterzähne“ saßen sowohl im seitlichen Bereich der Kiefer, als auch auf dem Gaumen. Placodontier sind bisher nur aus der Triaszeit bekannt und brachten eine Reihe von verschiedenen Körperformen hervor. Einige Arten erinnern an die heutigen Galapagos-Meerechsen, andere mit ihrer Gestalt und dem Panzer aus Knochenplatten eher an Meeresschildkröten. Die meisten Placodontier wurden etwa 1 oder 2 m lang. Sie gehören in die weitere Verwandtschaft der Schuppenkriechtiere (Echsen und Schlangen), haben aber keine lebenden Verwandten mehr.
Gogolin gehört zu den klassischen Fundstellen für Muschelkalkfossilien und lieferte auch schon früh Wirbeltierfossilien. So berichtete bereits Hermann von Meyer, der Vater der Wirbelpaläontologie in Deutschland, in seiner Monographie „Die Saurier des Muschelkalkes mit Rücksicht auf die Saurier aus dem bunten Sandstein und Keuper“ (Meyer, 1847-1855) von Reptilienfunden aus dem Gogoliner Raum. Später erforschten zum Beispiel Georg Gürich aus Breslau und Anton Schrammen aus Hildesheim weiteres Material (Gürich, 1884; Schrammen, 1899). Nebst Gogolin selbst sind auch andere Fundorten in Oberschlesien für Muschelkalkfossilien bekannt, so zum Beispiel Chorzów (Königshütte), Krapkowice (Krappitz), Zakrzów (Sakrau/Sacrau) oder Tarnowskie Góry (Tarnowitz)...

A new basal elasmosaurid (Sauropterygia: Plesiosauria) from the Lower Cretaceous of Germany

Sachs, S., Hornung, J. J. & Kear, B. P. (2017) A new basal elasmosaurid (Sauropterygia: Plesiosauria) from the Lower Cretaceous of Germany. Journal of Vertebrate Paleontology, 37(4): e1301945. [Request a pdf]

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Here we report on a new basal elasmosaurid plesiosaurian, Lagenanectes richterae, gen. et sp. nov., from the Lower Cretaceous (probably Upper Hauterivian) of Germany. The material includes a partial skull (cranium and mandible), the atlas-axis complex, additional cervical vertebrae, caudal vertebrae, an ilium, and limb elements. The basioccipital and atlas intercentrum are pathologically deformed, probably due to an osteomyelitic infection. Two potential autapomorphies were found in the mandible: (1) the alveolar margin at the symphysis is laterally expanded with the rostral-most alveoli being markedly procumbent and situated along the lateral margins of the dentaries; and (2) the ventral midline at the symphysis is produced into a prominent wedge-shaped platform indented by numerous irregular pits. Lagenanectes richterae, gen. et sp. nov., also shows a number of typical elasmosaurid traits, including a longitudinal lateral ridge on the cervical vertebral centra (although a ventral notch is absent) and teeth with oval cross-sections. Lagenanectes richterae, gen. et sp. nov., is one of the best-preserved plesiosaurians from the Lower Cretaceous of Europe.

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On the largest Ichthyosaurus: A new specimen of Ichthyosaurus somersetensis containing an embryo
Lomax, D. & Sachs, S. (2017) On the largest Ichthyosaurus: A new specimen of Ichthyosaurus somersetensis containing an embryo. Acta Palaeontologica Polonica 62(3): 575-584.
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A formerly undescribed Ichthyosaurus specimen from the collection of the Niedersächsisches Landesmuseum (Lower Saxony State Museum) in Hannover, Germany, provides valuable new information. The skeleton was collected from the Lower Jurassic strata (lower Hettangian, Blue Lias Formation) of Doniford Bay, Somerset, UK. However, the specimen is a composite as almost the entire tail has been added and other parts are reconstructed. Regardless of the incomplete preservation, the estimated total length of this individual, based on the skull and precaudal length, is between 300 and 330 cm and it is thus the largest unequivocal example of the genus Ichthyosaurus. Cranial and postcranial characters, specifically from the maxilla, lacrimal, jugal, the humerus, and the ilium justify a referral to I. somersetensis. A fork-
Lomax & Sachs (2017) On the largest Icht
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Pliosauromorph plesiosaurian remains from the Late Cretaceous of northwestern Germany
Sachs, S., Bertling, M. & Kear, B.P. (2017) Pliosauromorph plesiosaurian remains from the Late Cretaceous of northwestern Germany. In: 15th Annual Meeting of the European Association of Vertebrate Palaeontologists Munich, Germany. Zitteliana 91: 78-79.
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Plesiosaurian skeletal remains are rare in Late Cretaceous strata of Europe. During several years in the 1950`s, various cranial and postcranial elements of a pliosauromorph plesiosaurian had been collected by amateurs at Anröchte, North Rhine-Westphalia, northwestern Germany. They were donated to the Geomuseum of the WWU, Münster, but remained unstudied over decades: their softness combined with the embedment in a hard siliceous rock precluded preparation until suitable techniques were developed. These remains represent the most complete plesiosaurian reptile find from Turonian strata in Europe, but they have only been studied provisionally as yet. The material comes from the Soest Greensand Member (Salder Formation) of Late Turo
Sachs, Bertling _ Kear (2017) Pliosaurom
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Reappraisal of the ʽDorking Specimen’: An Upper Cretaceous Brachauchenine Pliosaurid from England
Madzia, D., Sachs, S., Evans, M., Lindgren, J., Kear, B.P. & Cau, A. (2017) Reappraisal of the ʽDorking Specimen’: An Upper Cretaceous Brachauchenine Pliosaurid from England. In: 15th Annual Meeting of the European Association of Vertebrate Palaeontologists Munich, Germany. Zitteliana 91: 55-56.
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Brachauchenine pliosaurids were marine macropredatory reptiles that might have been the only evolutionary lineage of pliosaurid plesiosaurians that crossed the Jurassic-Cretaceous boundary. Yet progress in understanding their origins and phylogenetic relationships has been hindered by limited knowledge of Early Cretaceous brachauchenine pliosaurid diversity and disparity relative to Late Cretaceous members of the clade. Late Cretaceous brachauchenines currently include only three valid taxa: Brachauchenius lucasi and Megacephalosaurus eulerti, initially described from the Turonian of Kansas, as well as ʽPolyptychodonʼ hudsoni from the Turonian of Texas. In Europe, the clade has long b
Madzia, Sachs et al. (2017) Reappraisal
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Redescription of the elasmosaurid plesiosaurian Libonectes atlasense from the Upper Cretaceous of Morocco

Sachs, S. & Kear, B.P. (2017) Redescription of the elasmosaurid plesiosaurian Libonectes atlasense from the Upper Cretaceous of Morocco. Cretaceous Research 74: 205-222. [Request a pdf]

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The holotype of Libonectes atlasense is an almost complete skeleton from Upper Cretaceous (mid-Turonian) rocks of the Goulmima area in eastern Morocco. Initial assessment of this specimen in 2005 proposed generic referral based on stratigraphical contemporaneity with Libonectes morgani from the Cenomanian–Turonian of Texas, U.S.A. Nevertheless, relative differences in the profile of the premaxillary-maxillary tooth row, position of the external bony nasal opening, number of teeth and rostral inclination of the mandibular symphysis, proportions of the axial neural arch, and number of cervical and pectoral vertebrae were used to distinguish between these species. As part of an on-going comparative appraisal of elasmosaurid plesiosaurian osteo-anatomy, we re-examined the type and formally referred material of both L. atlasense and L. morgani in order to establish species validity, as well as compile a comparative atlas for use in future works. Our inspections revealed that these reportedly distinct species-level fossils are in fact virtually indistinguishable in gross morphology. Indeed, the only substantial difference occurs in relative prominence of the midline keel along the mandibular symphysis, which might be explained by intraspecific variation. Furthermore, our observations permit an amendment to the published generic diagnosis of Libonectes with the confirmation of important states such as the likely presence of a pectoral bar, distocaudal expansion of the humerus, and an epipodial foramen. In addition, novel features include a prominent ‘prong-like’ ventral midline process on the coracoids, and the development of a median pelvic bar that encloses a central fenestration. The composite remains of L. morgani thus constitute one of the most complete elasmosaurid skeletal hypodigms documented worldwide, and evidence a trans-Atlantic distribution for this apparently dispersive species during the early–Late Cretaceous.

Cenomanian–Turonian marine amniote remains from the Saxonian Cretaceous Basin of Germany

Sachs, S., Wilmsen, M., Knüppe, J., Hornung, J. & Kear, B.P. (2017) Cenomanian–Turonian marine amniote remains from the Saxonian Cretaceous Basin of Germany. Geological Magazine 154(2): 237-246. [Request a pdf]

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The Saxonian Cretaceous Basin constitutes an important source of rare Late Cretaceous marine amniote fossils from Germany. It is also historically famous, having been documented in a series of monographic works published by the distinguished German palaeontologist Hanns Bruno Geinitz in the nineteenth century. The most productive rock units include the upper Cenomanian Dölzschen Formation and upper Turonian Strehlen and Weinböhla limestones (lower Strehlen Formation). A survey of curated specimens recovered from these deposits has now identified isolated teeth of probable polycotylid and elasmosaurid plesiosaurians, as well as several humeri that are referred to protostegid marine turtles. The Saxonian Cretaceous Basin formed a continuous epeiric seaway with the Bohemian Cretaceous Basin during late Cenomanian – Turonian time. A western connection to the North Sea Basin also existed via the North German and Münsterland Cretaceous basins. The Mesozoic marine amniote remains from these regions therefore record a coeval northern European fauna that was probably homogeneous across the northern peri-Tethyan margin during Late Cretaceous time.

2016


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Kreide-Fossilien in Sachsen. Teil 15. Reptilien / Reptiles
Sachs, S.; Hornung, J. J.; Knüppe, J.; Wilmsen, M. & Kear, B.P. (2016) 15. Reptilien / 15. Reptiles. In: Niebuhr, B.; Wilmsen, M. (eds.) Kreide-Fossilien in Sachsen, Teil 2. Geologica Saxonica 62: 169-179.
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Reptilien gehören in der sächsischen Kreide (Elbtal-Gruppe) zu den Seltenheiten. Die wenigen bekannten Reste sind historische Funde, die erstmals im 19. Jahrhundert von Hanns Bruno Geinitz bearbeitet wurden. Sie stammen aus zwei stratigraphischen Einheiten, der Dölzschen-Formation (oberes Obercenomanium) sowie dem Strehlener und Weinböhlaer Kalk der unteren Strehlen-Formation (mittleres Oberturonium) und wurden fast ausschließlich im heutigen Stadtgebiet von Dresden gesammelt. Die Exemplare aus der Dölzschen-Formation sind sehr fragmentarisch erhalten und konnten keiner Gruppe mit Sicherheit zugeordnet werden. Das Material aus dem Strehlener Kalk hingegen zeigt, dass zwei Plesiosaurier-Familien (Elasmosauridae und ?Polycotylidae) sowie verschiedene marine S
Sachs, Hornung et al. (2016) Kreide-Foss
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Reappraisal of Europe’s most complete Early Cretaceous plesiosaurian: Brancasaurus brancai Wegner, 1914 from the “Wealden facies” of Germany
Sachs, S., Hornung, J.J. & Kear, B.P. (2016) Reappraisal of Europe’s most complete Early Cretaceous plesiosaurian: Brancasaurus brancai Wegner, 1914 from the “Wealden facies” of Germany. PeerJ 4 (5745).
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The holotype of Brancasaurus brancai is one of the most historically famous and anatomically complete Early Cretaceous plesiosaurian fossils. It derived from the Gerdemann & Co. brickworks clay pit near Gronau (Westfalen) in North Rhine-Westphalia, northwestern Germany. Stratigraphically this locality formed part of the classic European ''Wealden facies,'' but is now more formally attributed to the uppermost strata of the Bückeberg Group (upper Berriasian). Since its initial description in 1914, the type skeleton of B. brancai has suffered damage both during, and after WWII. Sadly, these mishaps have resulted in the loss of substantial information, in particular many structures of the cranium and limb girdles, which are today only evidenced from published text
Sachs, Hornung & Kear (2016) Reappraisal
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Cyclotosaurus buechneri – ein neuer Riesenlurch aus der oberen Trias von Bielefeld
Witzmann, F., Sachs, S. & Nyhuis, C. (2016) Cyclotosaurus buechneri – ein neuer Riesenlurch aus der oberen Trias von Bielefeld. Der Steinkern 27: 46-51.
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Mehrere Meter große, entfernt an Krokodile erinnernde Lurche, die sogenann-ten Capitosaurier, beherrschten in der Trias die limnischen Ökosysteme in wei-ten Teilen der Welt. Ein Vertreter der Capitosaurier, der aufgrund seiner rund-um geschlossenen Ohröffnung zu den Rundohrlurchen (Cyclotosaurier) gezählt werden kann, wurde vor über 40 Jahren im Schilfsandstein der oberen Trias von Bielefeld entdeckt – ein Novum für Norddeutschland, findet man die Überreste solcher Riesen doch zumeist in triassischen Sedimenten Süddeutschlands. Der Fund wurde jetzt erstmals wissenschaftlich ausgewertet und es zeigte sich, dass es sich um eine neue Art der Gattung Cyclotosaurus handelt.
Witzmann, Sachs _ Nyhuis (2016) Cyclotos
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Reste von protostegiden Meeresschildkröten aus dem Cenomanium (Oberkreide) des Kassenberges (Mülheim an der Ruhr, Westdeutschland
Sachs, S., Scheer, U. & Rabi, M. (2016) Reste von protostegiden Meeresschildkröten aus dem Cenomanium (Oberkreide) des Kassenberges (Mülheim an der Ruhr, Westdeutschland / Protostegid marine turtle remains from the Cenomanian (Late Cretaceous) of the Kassenberg (Mülheim an der Ruhr, Western Germany). Berichte Naturwissenschaftlicher Verein für Bielefeld und Umgegend 54: 32-43.
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Postcraniale Reste von protostegiden Schildkröten aus dem unteren Untercenomanium von Mülheim an der Ruhr (Westdeutschland) werden vorgestellt. Das Material umfasst fragmentarische Reste des Carapax und Appendikularskeletts eines Taxons mit einer mittleren Carapax- Länge von etwa 20-30 cm. Die Schildkrötenreste ergänzen den Nachweis dieser Gruppe im Cenomanium Deutschlands, sowie die Fauna des Kassenbergs. Postcranial remains of protostegid turtles from the lowermost Cenomanian of Mülheim an der Ruhr (Western Germany) are described. The material includes fragments from the carapace a
Sachs, Scheer _ Rabi (2016) Reste von pr
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Big-headed marine crocodyliforms and why we must be cautious when using extant species as body length proxies for long-extinct relatives
Young, M., Rabi, M., Bell, M., Foffa, D., Steel, L., Sachs, S. & Peyer, K. (2016) Big-headed marine crocodyliforms and why we must be cautious when using extant species as body length proxies for long-extinct relatives. Palaeontologia Electronica 19.3.(30A:): 1-14.
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Body size is commonly used as a key variable for estimating ecomorphological trends at a macroevolutionary scale, making reliable body length estimates of fossil taxa critically important. Crocodylomorphs (extant crocodylians and their extinct relatives) evolved numerous 'aberrant' body-plans during their ~230 million-year history, ranging from ‘hooved’ terrestrial species to dolphin-like pelagic species. Such clades evolved distinct cranial and femoral scaling ratios (compared to total body length), thereby making extant taxa unsuitable proxies for estimating their body lengths. Here we illustrate that the fossil clade Teleosauridae also fits into this category. Teleosaurids were a predominately shal
Young, Rabi et al. (2016) Big-headed mar
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Overview of Marine Reptiles from the Turonian of the Opole area, southwest Poland
Sachs, S., Niedźwiedzki, R., Kędzierski, M., Kear, B.P., Jagt-Yazykova, E. & Jagt, J.W.M. (2016) Overview of Marine Reptiles from the Turonian of the Opole area, southwest Poland. XIV Annual Meeting of the European Association of Vertebrate Palaeontologist: 80.
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Turonian strata in the Opole area are well known for their well-preserved invertebrate fossils. Amongst the earliest descriptions is Leonhard’s 1897 monograph “Die Fauna der Kreideformation in Oberschlesien”, in which some isolated tetrapod elements, including mosasauroid and plesiosaurian teeth as well as a fragmentary bone named Plesiosauridarum were listed. Part of Leonhard's material is now curated in the collection of the Department of Paleozoology of University of Wrocław. Further, yet undescribed, specimens were found in the collection of the Ruhrmuseum in Essen. At present several plesiosaurian teeth, one mosasauroid tooth and a paddle element (? a plesiosaurian mesopodial) are available. Le
Sachs, Niedźwiedzki et al. (2016) Overvi
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5th Triennial Mosasaur Meeting – a global perspective on Mesozoic marine amniotes. Abstracts and Program
Kear, B.P., Lindgren, J. & Sachs, S. (eds) (2016) 5th Triennial Mosasaur Meeting – a global perspective on Mesozoic marine amniotes. Abstracts and Program: 49 p.
Kear, Lindgren & Sachs (2016) 5th Trienn
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Evidence for a Simolestes-like plesiosaurian from the Berriasian (Lower Cretaceous) limnic-brackish Bückeberg group of northwestern Germany
Sachs, S., Hornung, J.J., Lallensack, J. & Kear, B.P. (2016) Evidence for a Simolestes-like plesiosaurian from the Berriasian (Lower Cretaceous) limnic-brackish Bückeberg group of northwestern Germany. In: Sachs, S., Kear, B.P. & Lindgren (eds) 5th Triennial Mosasaur Meeting – a global perspective on Mesozoic marine amniotes. Abstracts and Program: 35-37.
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The middle to late Berriasian Bückeberg Group of northwestern Germany has yielded a number of plesiosaurian fossils. These include Europe's most complete Lower Cretaceous plesiosaurian, Brancasaurus brancai, in the fine grained, argillaceous Isterberg Formation near Gronau in Westfalen. Recently a second taxon, Gronausaurus wegneri was identified from the same locality and stratum (Hampe 2013) A higher diversity in the Bückeberg Group plesiosaurian assemblage is indicated by pliosauromorph and other plesiosaurian vertebrae from strata in the upper part of the sequence (see e.g. Koken 1896; Hornung et al., 201
Sachs, Hornung et al. (2016) Evidence fo
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Re-description of Thalassomedon haningtoni – an elasmosaurid from the Cenomanian of North America
Sachs, S., Kear, B.P. & Lindgren, J. (2016) Re-description of Thalassomedon haningtoni – an elasmosaurid from the Cenomanian of North America. In: Sachs, S., Kear, B.P. & Lindgren (eds) 5th Triennial Mosasaur Meeting – a global perspective on Mesozoic marine amniotes. Abstracts and Program: 38-40.
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halassomedon haningtoni is one of the most thoroughly documented elasmosaurids. The type specimen, a nearly complete skeleton representing an osteologically mature individual with a well preserved postcranium (but damaged skull) was found in Cenomanian strata of the Graneros Shale in Colorado, USA. The only comprehensive description of this specimen produced so far is that of Welles (1943); however, his interpretations are contentious and require substantial updating relative to subsequent elasmosaurid discoveries. A second specimen of T. haningtoni is also known from the Cenomanian Graneros Shale of Nebraska, USA. This skeleton comprises a well preserved skull and art
Sachs, Lindgren _ Kear (2016) Re-descrip
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A reassessment of historical plesiosaurian specimens from the Turonian (lower Upper Cretaceous) of the Opole area, southwest Poland
Sachs, S., Niedźwiedzki, R., Kędzierski, M., Kear, B.P., Jagt-Yazykova, E. & Jagt, J.W.M. (2016) A reassessment of historical plesiosaurian specimens from the Turonian (lower Upper Cretaceous) of the Opole area, southwest Poland. In: Sachs, S., Kear, B.P. & Lindgren (eds) 5th Triennial Mosasaur Meeting – a global perspective on Mesozoic marine amniotes. Abstracts and Program: 40-42.
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In 1897, Richard Leonhard presented brief descriptions and some illustrations of a few plesiosaurian remains (teeth and a supposed phalanx) from the lower Turonian of the Opole area (southwest Poland). Leonhard assigned the teeth to Polyptychodon interruptus and established a new genus, Plesiosauridarum (a species name was not supplied, making this a nomen nudum), for the supposed phalanx. Until recently, the whereabouts of all these specimens were unknown. However, during a recent survey of several Polish and German collections, most of Leonhard’s specimens could be relocated. Fur
Sachs, Niedźwiedzki et al. (2016) A reas
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Plesiosaurian fossils from Baltic glacial erratics: evidence of Early Jurassic marine amniotes from the southwestern margin of Fennoscandia

Sachs, S., Hornung, J. J. & Kear, B.P. (2016) Plesiosaurian fossils from Baltic glacial erratics: evidence of Early Jurassic marine amniotes from the southwestern margin of Fennoscandia. In: Kear, B.P., Lindgren, J., Hurum, J.H., Milán, J. & Vajda, V. (eds.) Mesozoic biotas of Scandinavia and its Arctic territories. Geological Society, London, Special Publications 434: 149-163. [Request a pdf]

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Early Jurassic plesiosaurian fossils are rare in the Scandinavian region, with a few isolated bones and teeth known from Bornholm, and anecdotal finds from East Greenland. The only other identifiable specimens derive from Toarcian-aged (based on ammonites) erratics deposited during Late Pleistocene glacial advances near the town of Ahrensburg, NE of Hamburg in northern Germany. The geographical source of these transported clasts is debated, but reconstructed ice-flow directions and lithofacies comparisons implicate either the offshore Baltic Sea between the Island of Bornholm and Mecklenburg–Vorpommern (Germany) or, less probably, south of the Danish Archipelago (Mecklenburg Bay). These regions collectively bordered the Fennoscandian landmass and adjacent Ringkøbing-Fyn Island in the late Early Jurassic, and were dominated by near-shore marine deltaic to basinal settings. The Ahrensburg plesiosaurian remains include postcranial elements reminiscent of both the microcleidid Seeleyosaurus and the rhomaelosaurid Meyerasaurus. These occur alongside other classic ‘Germanic province’ marine amniotes, such as the teleosaurid crocodyliform Steneosaurus and ichthyosaurian Stenopterygius cf. quadriscissus: thus, advocating faunal continuity between Scandinavia and southern Germany during the Toarcian, and a less pronounced marine reptile faunal provinciality than previously assumed.

A partial plesiosaurian braincase from the Upper Cretaceous of Sweden

Sachs, S., Lindgren, J. & Siversson, M. (2016) A partial plesiosaurian braincase from the Upper Cretaceous of Sweden. In: Kear, B.P., Lindgren, J., Hurum, J.H., Milán, J. & Vajda, V. (eds.) Mesozoic biotas of Scandinavia and its Arctic territories. Geological Society, London, Special Publications 434: 293-301. [Request a pdf]

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A partial exoccipital–opisthotic from the uppermost lower Campanian (Upper Cretaceous) of the Åsen locality, Kristianstad Basin, southernmost Sweden, is described and illustrated. The fossil represents the first braincase element of a plesiosaur found in Sweden. It includes the chamber for the ampulla and utriculus, openings for the caudal vertical and horizontal semicircular canals, and four foramina for cranial nerves. The incomplete braincase can be referred to an elasmosaurid plesiosaur, and closely resembles the exoccipital–opisthotic of Libonectes morgani and a referred specimen of Aristonectes parvidens. Although we discuss putative postcranial material of the elasmosaurid subfamily Aristonectinae in the uppermost lower Campanian of southernmost Sweden, the exoccipital–opisthotic from Åsen most likely belongs to a juvenile individual of a non-aristonectine elasmosaur.

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A new species of Cyclotosaurus (Stereospondyli, Capitosauria) from the Late Triassic of Bielefeld, NW Germany, and the intrarelationships of the genus
Witzmann, F., Sachs, S. & Nyhuis, C. (2016) A new species of Cyclotosaurus (Stereospondyli, Capitosauria) from the Late Triassic of Bielefeld, NW Germany, and the intrarelationships of the genus. Fossil Record 19(2): 83-100.
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A nearly complete dermal skull roof of a capi-tosaur stereospondyl with closed otic fenestrae from the middle Carnian Stuttgart Formation (Late Triassic) of Bielefeld-Sieker (NW Germany) is described. The specimen is assigned to the genus Cyclotosaurus based on the limited contribution of the frontal to the orbital margin via narrow lateral processes. A new species, Cyclotosaurus buechneri sp. nov., is erected based upon the following unique combination of characters: (1) the interorbital distance is short so that the orbitae are medially placed (shared with C. robustus); (2) the region lateral to the orbitae is only slightly broader than the orbitae (shared with C. posthumus, C. ebrachen-sis, C. intermedius, and C. mordax); (3) the postorbital
Witzmann, Sachs _ Nyhuis (2016) A new sp
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2015


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Fossil Focus: Elasmosaurs
Sachs, S. & Kear, B.P. (2015) Fossil Focus: Elasmosaurs. Palaeontology Online, Volume 5, Article 2: 1-8.
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Elasmosaurs were a group of marine reptiles that lived during the Cretaceous period (about 145 million to 66 million years ago). They were fully adapted to an aquatic lifestyle, and had a distinctive body plan comprising a compact, streamlined body, long, paddle-like limbs and an extremely elongated neck with a large number of vertebrae (Fig. 1). The first named elasmosaur was Elasmosaurus platyurus from the Late Cretaceous (Campanian stage, about 83.6 million to 72.1 million years ago). It was found in Kansas and described by the famous US scientist Edward Drinker Cope (1840–97, Fig. 2), who, when he first wrote about it in 1868, believed that the almost complete series of 72 neck vertebrae came from a massively long tail. Today, many articulated skeletons of elasmosaurs provide insight in the anatomy, lifestyle and relationships of these spectacular ancient
Sachs & Kear (2015) Fossil Focus Elasmos
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Belege für riesige Pliosaurier aus dem Jura Deutschlands
Sachs, S. & Nyhuis, C. (2015) Belege für riesige Pliosaurier aus dem Jura Deutschlands. Der Steinkern 21: 74-82
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Pliosaurier gehören zu den größten Meeresreptilien, die je gelebt haben. Vom Mittleren Jura bis in die obere Unterkreide erreichten einige Gattungen gigantische Ausmaße und standen meist an der Spitze der Nahrungskette. In den letzten Jahren haben besonders zwei Pliosaurier-Funde das Interesse der Öffentlichkeit erregt. Einer davon ist als „Monster von Aramberri“ bekannt geworden. Es handelt sich dabei um ein unvollständiges Skelett aus dem Kimmeridgium von Mexiko, dessen fossile Überreste von Buchy et al. (2003) als nicht näher bestimmbarer Pliosauride beschrieben wurden. Das Tier erreichte vermutlich eine Gesamtlänge von 15 m. Der zweite populär gewordene Fund, gleichfalls ein unvollständiges Skelett, stammt aus dem Tithonium von Svalbard (Spitzbergen) und erhielt den Spitznamen „Predator X“. Das Exemplar wurde von Knutsen et al. (201
Sachs _ Nyhuis (2015) Belege für riesige
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Megacnemus – a forgotten reptile, presumably from the Triassic of Poland
Skawiński, T.,Tałanda, M. & Sachs, S. (2015) Megacnemus – a forgotten reptile, presumably from the Triassic of Poland. In: J. Jagt, G. Hebda, S. Mitrus, E. Jagt-Yazykova, A. Bodzioch, D. Konietzko-Meier, K. Kardynał, K. Gruntmejer (ed.) EAVP. XIII Meeting Opole, Abstracts: 139.
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Protorosaurs were important components of many Permian and Triassic ecosystems. Some of the known protorosaurian taxa have been established on the basis of fragmentary material. One of these is Megacnemus grandis von Huene, 1954, of which only a single complete, yet distorted propodial – originally interpreted as a femur – is known. Although exact locality data are missing, von Huene (1954) pointed out that the specimen had most probably been found in the Middle Triassic deposits near Gogolin (southwest Poland). Since its initial description the genus Megacnemus has received very little attention. Our attempt is to redescribe the type specimen and assess the phylogenetic position of
Skawiński, Talanda _ Sachs (2015) Megacn
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A new basal elasmosaurid skeleton with joint pathologies from the Lower Cretaceous of Germany
Sachs, S., Hornung, J., Wohlsein, P. & Kear, B. (2015) A new basal elasmosaurid skeleton with joint pathologies from the Lower Cretaceous of Germany. In: J. Jagt, G. Hebda, S. Mitrus, E. Jagt-Yazykova, A. Bodzioch et al. (eds.) EAVP. XIII Meeting Opole, Abstracts: 131.
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The family Elasmosauridae constitutes one of the most iconic plesiosaurian clades. Their conservative body plan represents the popular model for Plesiosauria, and is characterised by a distinctive osteological morphology especially adapted for hyper-elongation of the neck. Here we report on a new basal elasmosaurid from the Lower Cretaceous (upper Hauterivian) of Lower Saxony, northern Germany. The fossil comprises skeletal components from an osteologically old individual: most of the cranium and partial mandible, the atlas-axis complex, cervical and caudal vertebrae, ribs, an ilium and paddle elements. The specimen displays a number of primitive elasmosaurid traits including five premaxillary teeth and amphicoelous
Sachs, Hornung et al. (2015) A new basal
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Marine Tetrapoden aus dem Mittleren Jura (Aalenium und Bajocium) von Bielefeld (Nordwestdeutschland)
Sachs, S. & Hornung, J. J. (2015) Marine Tetrapoden aus dem Mittleren Jura (Aalenium und Bajocium) von Bielefeld (Nordwestdeutschland) / Marine tetrapods from the Middle Jurassic (Aalenian and Bajocian) of Bielefeld (northwest Germany). Berichte Naturwissenschaftlicher Verein für Bielefeld und Umgegend 53: 52-73.
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Bisher unbeschriebene Reste von marinen Tetrapoden aus dem Oberaalenium (Ludwigienton-Formation) und Oberbajocium (Parkinsonienton-Formation) von Bielefeld-Bethel werden vorgestellt. In beiden stratigraphischen Intervallen lassen sich Thalattosuchier, Ichthyosaurier und Plesiosaurier nachweisen. Dieser Befund zeigt das persistieren typischer unterjurassischer Faunenelemente tieferer Beckenbereiche in den Mitteljura hinein an, und ist von besonderem Wert, da sowohl aus dem Aalenium als auch aus dem Bajocium Mitteleuropas nur wenige Funde mariner Tetrapoden bekannt sind. Beide Faunen kamen unter transgressiven oder Hochstandsbedingungen zur Ablagerung. Hithe
Sachs _ Hornung (2015) Marine Tetrapoden
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Postcranium of the paradigm elasmosaurid plesiosaurian Libonectes morgani (Welles, 1949)

Sachs, S. & Kear, B.P. (2015) Postcranium of the paradigm elasmosaurid plesiosaurian Libonectes morgani (Welles, 1949). Geological Magazine 152(4): 694-710. [Request a pdf]

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Elasmosauridae constitutes one of the most immediately recognizable plesiosaurian radiations. Their distinctive body plan represents the popular model for Plesiosauria, and is typified by an osteological morphology especially adapted for hyper-elongation of the neck. Nevertheless, many archetypal elasmosaurids are known only from incomplete and/or inadequately documented material, a problem that has contributed to their uncertain intra-clade relationships. A prime example of this is Libonectes morgani from the Upper Cretaceous of Texas, USA, which is frequently presented as an elasmosaurid structural proxy because of its three-dimensionally preserved holotype skull. Perplexingly though, both the taxonomic diagnosis and phylogenetic placement of L. morgani rely primarily upon the cervical vertebrae, together with the pectoral girdle and forelimb, yet most of these elements are now lost and figured only as line drawings. We therefore reviewed the remnant postcranial skeleton of L. morgani first-hand with the objective of clarifying its defining character states. Our observations showed that the existing diagnosis of L. morgani is indeed inadequate. Moreover, the only identifiable autapomorphies occurred within the axial skeleton. This concurred with an examination of character scores used in published plesiosaurian phylogenies, and highlights the persistent significance of postcranial elements for discriminating elasmosaurid taxa.

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Mosasaurs from Germany – a brief history of the first 100 years of research
Sachs, S., Hornung, J.J. & Reich, M. (2015) Mosasaurs from Germany – a brief history of the first 100 years of research. Netherlands Journal of Geosciences – Geologie en Mijnbouw 94(1): 5-18.
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In Germany, mosasaur remains are very rare and only incompletely known. However, the earliest records date back to the 1830s, when tooth crowns were found in the chalk of the Isle of Rügen. A number of prominent figures in German palaeontology and geosciences of the 19th and 20th centuries focused on these remains, including, among others, Friedrich von Hagenow, Hermann von Meyer, Andreas Wagner, Hanns Bruno Geinitz and Josef Pompeckj. Most of these works were only short notes, given the scant material. However, the discovery of fragmentary cranial remains in Westphalia in 1908 led to a more comprehensive discussion, which is also of historical importance, as it illustrates the discussions on the highly controversial and radical universal phylogenetic theory proposed by Gu
Sachs, Hornung _ Reich (2015) Mosasaurs
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2014


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Mitteilung über ein neues Skelett eines Plesiosauriers (Reptilia: Sauropterygia) aus dem Oberen Pliensbachium (Unterjura) von Bielefeld, Nordwestdeutschland
Sachs, S., Schubert, S., Kear, B.P. (2014) Mitteilung über ein neues Skelett eines Plesiosauriers (Reptilia: Sauropterygia) aus dem Oberen Pliensbachium (Unterjura) von Bielefeld, Nordwestdeutschland / Note on a new plesiosaur (Reptilia: Sauropterygia) skeleton from the upper Pliensbachian (Lower Jurassic) of Bielefeld, northwest Germany. Berichte Naturwissenschaftlicher Verein für Bielefeld und Umgegend 52: 26-35.
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Wir stellen einen neuen Plesiosaurier-Fund aus dem Oberen Pliensbachium (Unterer Jura) von Bielefeld-Jöllenbeck (Nordrhein-Westfalen, NW Deutschland) vor. Die erhaltenen Partien des Skeletts umfassen Teile des Schädels, der Wirbelsäule, der Rippen, des Schultergürtels sowie der Extremitäten. Es gehörte zu einem nicht ausgewachsenen Individuum von etwa 2-3 m Länge. Wichtige diagnostische Merkmale sind unter anderem eine markante Einkerbung in der caudalen Begrenzung der Fossa glenoidalis der Mandibula, craniale Cervicalwirbelcentra die höher als
Sachs, Schubert _ Kear (2014) Mitteilung
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Ein gepanzerter Dinosaurier aus der Unterkreide Westfalens
Sachs, S. & Hornung J. J. (2014) Ein gepanzerter Dinosaurier aus der Unterkreide Westfalens. Der Steinkern 18(3): 29-36.
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Die Tongrube Gerdemann bei Gronau (Westfalen) zählt zu den bedeutendsten historischen Fundpunkten für Wirbeltierfossilien aus der Unteren Kreide in Deutschland. Aus diesem Aufschluss werden zwei Knochen vorgestellt, die sich in der Sammlung der Universität Münster bzw. der Ausstellung des Drilandmuseums in Gronau befinden und dort lange ein wenig beachtetes Dasein fristeten. Die wissenschaftliche Untersuchung zeigte jüngst, dass es sich um Knochen von Ankylosauriern handelt, deren Vorkommen in Deutschland bis dato noch nicht sicher belegt war.
Keywords: Ankylosauria, Hylaeosaurus, Metatetrapodus, Lower Cretaceous, Wealden
Sachs _ Hornung (2014) Ein gepanzerter D
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Meeresreptilien vom Südpol der Unterkreide
Sachs, S. & Kear, B.P. (2014) Meeresreptilien vom Südpol der Unterkreide. Fossilien 3/2014: 16-22.
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Während der späten Unterkreide (Aptium, Albium) war das Gebiet des heutigen Australiens noch mit der Antarktis vereint. Die gemeinsame Landmasse befand sich in der Nähe des damaligen Südpols; die Wassertemperaturen fielen zum Teil unter den Gefrierpunkt. Dennoch lebte dort eine artenreiche Fauna, die unter anderem marine Reptilien wie Ichthyosaurier und Plesiosaurier umfasste. Sie waren offensichtlich an diese kalten Temperaturen angepasst. Vielleicht besaßen sie einen hohen Körperfettanteil, führten saisonale Wanderungen durch oder hatten einen erhöhten Stoffwechsel. Keywords: Platypterygius, Kronosaurus, Opallionectes, Umoonasaurus, Eromangasaurus, Bouliachelys, Lower Cretaceous, Australia
Sachs _ Kear (2014) Meeresreptilien vom
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2013


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Sauropterygian fossils from the predominantly limnic–brackish Bückeberg Formation (Berriasian–Early Valanginian, Early Cretaceous) of northwestern Germany – diversity, distribution, and palaeoe
Hornung, J.J., Sachs, S. & Kear, B.P. (2013) Sauropterygian fossils from the predominantly limnic–brackish Bückeberg Formation (Berriasian–Early Valanginian, Early Cretaceous) of northwestern Germany – diversity, distribution, and palaeoecology. In: Reitner, Yang, Wang & Reich (eds.) Palaeobiology and Geobiology of Fossil Lagerstätten through Earth History: 75.
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The Bückeberg Formation (Lower Saxony Basin, northern Germany and eastern Netherlands) represents a siliciclastic succession, deposited during the mid-Berriasian through to the earliest Valanginian. The unit is predominantly lacustrine with fluvial inflow and episodic marine connections to the Boreal Sea. Its fossil faunas include sauropterygian remains comprising isolated bones and partial, articulated skeletons. Though most of these finds cannot be identified at genus level, there is evidence of at least three morphotypes, representing distinct taxa: “Plesiosaurus degenhardti” Koken, 1887; Bra
Hornung et al. (2013) Sauropterygian fos
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Revised vertebral count in the ‘‘longest-necked vertebrate’’ Elasmosaurus platyurus Cope 1868, and clarification of the cervical-dorsal transition in Plesiosauria
Sachs, S., Kear, B.P. & Everhart, M. (2013) Revised vertebral count in the ‘‘longest-necked vertebrate’’ Elasmosaurus platyurus Cope 1868, and clarification of the cervical-dorsal transition in Plesiosauria. PLoS ONE 8(8): e70877.
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Elasmosaurid plesiosaurians are renowned for their immensely long necks, and indeed, possessed the highest number of cervical vertebrae for any known vertebrate. Historically, the largest count has been attributed to the iconic Elasmosaurus platyurus from the Late Cretaceous of Kansas, but estimates for the total neck series in this taxon have varied between published reports. Accurately determining the number of vertebral centra vis-a`-vis the maximum length of the neck in plesiosaurians has significant implications for phylogenetic character designations, as well as the inconsistent terminology applied to some osteological structures. With these issues in mind, we reassessed the holotype of E. platyurus as a model for standardiz
Sachs et al. (2013) Revised vertebral co
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Cenomanian-Turonian mosasauroids from the Bohemian Cretaceous Basin
Kear, B.P., Sachs, S., Ekrt, P. & Hornung, J.J. (2013) Cenomanian-Turonian mosasauroids from the Bohemian Cretaceous Basin. In: Polcyn, M.J. & Jacobs, L.L. (eds) 4th Triennial International Mosasaur Meeting. Program and Abstracts. Dallas, Texas: 24.
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The Bohemian Cretaceous Basin (BCB) is an intracontinental depositional depression that extends from Brno in eastern Moravia, through Bohemia to the north and west of Prague, and across the Czech-German border into southern Saxony around Dresden. During the early Late Cretaceous, the BCB formed part of the continuous peri-Tethyan shelf of central and southern Europe, which was inundated by a northwesterly trending marine transgression extending between the Tethys Ocean and the Boreal North Sea Basin. Fossils of marine amniotes that inhabited this shallow epicontinental seaway have been documented for over 155 years, but have attracted little recent research attention in comparison to other more famous localities elsewhe
Kear et al. (2013) Cenomanian-Turonian m
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Ankylosaur remains from the Early Cretaceous (Valanginian) of northwestern Germany
Sachs, S. & Hornung J. J. (2013) Ankylosaur Remains from the Early Cretaceous (Valanginian) of Northwestern Germany. PLoS ONE 8(4).
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A fragmentary cervico-pectoral lateral spine and partial humerus of an ankylosaur from the Early Cretaceous (early
Valanginian) of Gronau in Westfalen, northwestern Germany, are described. The spine shows closest morphological
similarities to the characteristic cervical and pectoral spines of Hylaeosaurus armatus from the late Valanginian of England.
An extensive comparison of distal humeri among thyreophoran dinosaurs supports systematic differences in the
morphology of the distal condyli between Ankylosauria and Stegosauria and a referral of the Gronau specimen to the
former. The humerus fragment indicates a rather small individual, probably in the size range of H. armatus, and both
specimens are determined herein as ?Hylaeosaurus sp.. A short overview of other purported ankylosaur material from the
Berriasian-Valanginian of northwes
Sachs & Hornung (2013) Ankylosaur Remain
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2012


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Eine Fährtenplatte mit Chirotherium barthii KAUP und cf. Rotodactylus aus dem Oberen Buntsandstein (Untere Trias) von Pirmasens
Haderer, F.-O. & Sachs, S. (2012) Eine Fährtenplatte mit Chirotherium barthii KAUP und cf. Rotodactylus aus dem Oberen Buntsandstein (Untere Trias) von Pirmasens. Mitteilungen der POLLICHIA 96: 5-10.
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Aus der Sammlung des Pfalzmuseums für Naturkunde – POLLICHIA-Museum in Bad Dürkheim wird eine Fährtenplatte aus dem Oberen Buntsandstein (Untere Trias) von Pirmasens beschrieben, auf welcher die Fährtenart Chirotherium barthii KAUP und ein weiterer Fährtenrest cf. Rotodactylus erhalten ist. Sowohl Chirotherium barthii KAUP als auch cf. Rotodactylus stellen die ersten Nachweise dieser Taxa aus Rheinland-Pfalz dar.
Haderer _ Sachs (2012) Eine Fährtenplatt
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2011


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Ein elasmosaurider Plesiosaurier aus dem unteren Campan (Oberkreide) von Sehnde-Höver (Landkreis Hannover)
Sachs, S. (2011) Ein elasmosaurider Plesiosaurier aus dem unteren Campan (Oberkreide) von Sehnde-Höver (Landkreis Hannover). Arbeitskreis Paläontologie Hannover 39. 12-19.
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In der Sammlung von Herrn Udo Frerichs (Langenhagen) befinden sich einige craniale Reste eines Elasmosauriers. Die Stücke wurden im Frühjahr 1978 in der Grube „Alemannia“ in Sehnde-Höver bei Hannover entdeckt (FRERICHS 1994, 2005, FRERICHS & FRERICHS 1978). Nebst gut erhaltenen Zähnen unterschiedlicher Größe umfasst das Fundgut Teile der Mandibula, sowie einige nicht näher bestimmbare Knochenreste...
Sachs (2011) Ein elasmosaurider Plesiosa
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