Early Jurassic palaeopolar marine reptiles of Siberia

2020 ◽  
pp. 1-18
Author(s):  
Nikolay G. Zverkov ◽  
Dmitry V. Grigoriev ◽  
Igor G. Danilov
Keyword(s):  
Indirect Evidence ◽  
Wide Distribution ◽  
Lower Jurassic ◽  
Taxonomic Composition ◽  
Polar Night ◽  
Marine Reptiles ◽  
Polar Environment ◽  
Seasonal Migrations ◽  
Low Latitudes ◽  
Marine Reptile

Abstract Marine reptile occurrences are rare in the Lower Jurassic Series outside of Europe. Here we describe diverse marine reptile faunas from the Lower Jurassic Series (Pliensbachian and Toarcian stages, including the Toarcian–Aalenian boundary interval) of Eastern Siberia. The taxonomic composition of Toarcian marine reptile assemblages of Siberia highlight their cosmopolitan nature, with the presence of taxa previously known nearly exclusively from coeval strata of Europe, such as ichthyosaurians Temnodontosaurus and Stenopterygius, microcleidid plesiosaurians (including the genus Microcleidus), rhomaleosaurids and basal pliosaurids. The palaeogeographic reconstruction places these faunas to the palaeopolar region, north of the 80th northern parallel and up to the palaeo north pole (upper value within the 95% confidence interval for some of the localities). The materials include remains of both mature and juvenile (or even infant, judging by their very small size and poor ossification) animals, indicating a possibility that these polar seas may serve as a breeding area. The diversity and abundance of plesiosaurians and ichthyosaurians, along with a lack of thalattosuchian remains (considering their wide distribution elsewhere at low latitudes), is an additional argument that plesiosaurians and neoichthyosaurians were able to live and reproduce in a polar environment. There is no certainty whether these animals lived in polar seas permanently, or whether they were taking seasonal migrations. However, given the polar night conditions at high latitudes, the latter seems more plausible, and both these scenarios are further indirect evidence that these groups likely had a high metabolism.

scholarly journals Marine reptiles and climates of the Jurassic and Cretaceous of Siberia

2019 ◽  
Vol 27 (4) ◽  
pp. 13-39
Author(s):  
M. A. Rogov ◽  
N. G. Zverkov ◽  
V. A. Zakharov ◽  
M. S. Arkhangelsky
Keyword(s):  
Late Jurassic ◽  
New Records ◽  
Time Interval ◽  
Eastern Siberia ◽  
Warm Climate ◽  
The North ◽  
Marine Reptiles ◽  
Seasonal Migrations ◽  
Marine Reptile

All available data on the Jurassic and Cretaceous climates of Siberia, based on isotope, palaeontological and lithological markers are summarized. Late Pliensbachian cooling, early Toarcian warming, followed by late Toarcian to Middle Jurassic cooling and long-term Late Jurassic warming are well-recognized. Gradual cooling started since the late Ryazanian and continued during the whole Early Cretaceous except the short early Aptian warming event. At the beginning of the Late Cretaceous climate became warmer with warming peak at the Cenomanian–Turonian transition. During the middle and late Turonian climate became colder. During the Coniacian–Campanian time interval climate became warmer, but at the end of the Campanian new cooling event occurred. New records of marine reptiles from the Toarcian, Kimmeridgian, Volgian and Santonian–Campanian of the north of Eastern Siberia are described. All data concerning marine reptile occurrences in the Jurassic and Cretaceous of Siberia are reviewed; these records (from 51 localities) are mostly located at high palaeolatitudes. The analysis has revealed that most of the localities containing fossil reptile remains were llocated in the Transpolar palaeolatitudes (70°–87°). There are no direct relationship between climate oscillations and distribution of these animals. Taking into account recent data arguing that nearly all groups of the Jurassic and Cretaceous big marine reptiles were able to maintain constant body temperature and also were capable make long-range seasonal migrations, any conclusions concerning usage of these animals as markers of warm climate should be treated with a caution.

Jurassic bivalve biogeography

Paleobiology ◽  
1977 ◽  
Vol 3 (1) ◽  
pp. 58-73 ◽  
Author(s):  
A. Hallam
Keyword(s):  
Sea Level ◽  
Wide Distribution ◽  
Lower Jurassic ◽  
Taxonomic Composition ◽  
Extinction Rate ◽  
Ecological Groups ◽  
Sharp Rise ◽  
Extinction Rates ◽  
Endemic Genera ◽  
The Relationship

An analysis of the geographic and stratigraphic distribution of nearly 200 Jurassic bivalve genera leads to a number of new discoveries. Similarities between regions reached a maximum in the middle of the period, while the percentage of endemism correspondingly decreased. Diversity increased through the Lower Jurassic to a level which remained more or less stable from Middle Jurassic times onwards, while the origination rate shows the opposite trend. Extinction rate increased early in the period to a maximum in the Pliensbachian and fell thereafter to a low value until the Tithonian, which is marked by a sharp rise. The overall taxonomic composition of the fauna in terms of orders remained substantially stable throughout the period. The relationship with facies is discussed and three major ecological groups distinguished: marginal marine (euryhaline), shallow neritic and deep neritic. Certain pterioids have a very wide distribution and the order as a whole has a significantly higher proportion of cosmopolitan to endemic genera than any other order; the hippuritoids and trigonioids have the highest proportion of endemics. Five faunal provinces are distinguished, and the dominant control on distribution considered to be sea level. Times of high sea level were marked by widespread distribution of taxa and low endemism. High extinction rates were provoked both by regression (in the Tithonian) and by a sharp rise of sea level in the Toarcian, marked by the widespread onset of anaerobic or near-anaerobic conditions in many epicontinental seas. Some latitudinal control is recognised, notably for the hippuritoids and other stenotopic thick-shelled genera, which are confined to low latitudes.

New metrics to differentiate species ofStenopterygius(Reptilia: Ichthyosauria) from the Lower Jurassic of southwestern Germany

2012 ◽  
Vol 86 (1) ◽  
pp. 105-115 ◽  
Author(s):  
Erin E. Maxwell
Keyword(s):  
Soft Tissue ◽  
Multivariate Analyses ◽  
Research Effort ◽  
Measurement Data ◽  
Body Cavity ◽  
Lower Jurassic ◽  
The Body ◽  
Marine Reptiles ◽  
The World ◽  
Posidonia Shale

Ichthyosaurs represent one of the most highly specialized lineages of marine reptiles, but our understanding of the evolution of this group is based on specimens found at a surprisingly small number of stratigraphic intervals and localities. The Lower Jurassic (Toarcian) Posidonia Shale of southwestern Germany is one of the richest ichthyosaur-bearing formations in the world and has produced thousands of skeletons, including specimens with preserved soft tissue, and fetal remains inside the body cavity. The most abundant ichthyosaur genus in the Posidonia Shale isStenopterygius. In spite of almost 200 years of research effort, the number of species in this genus is still a point of active disagreement in the literature. Here, bivariate and multivariate analyses are used to classify both articulated and disarticulated skeletons to the level of species, using measurement data from individual cranial and postcranial elements. Unlike previous classification attempts, this technique pinpoints ontogenetically conserved differences in size and proportion between the species, and so can be applied to adult, subadult, and neonatal specimens. Using this method, three species ofStenopterygius, S. quadriscissus, S. triscissus, andS. uniterare differentiated.

Mesozoic palaeogeography and tectono-stratigraphic features of the northern Amerini Mts. (Central Apennines, Italy): new constraints on their Jurassic and Cretaceous evolution

2020 ◽  
Author(s):  
Costantino Zuccari ◽  
Angelo Cipriani ◽  
Massimo Santantonio
Keyword(s):  
Early Cretaceous ◽  
Lower Cretaceous ◽  
Carbonate Platform ◽  
Indirect Evidence ◽  
Lower Jurassic ◽  
Geological Mapping ◽  
Carbonate Platforms ◽  
Central Apennines ◽  
Sedimentary Evolution ◽  
Structural High

<p>A geological mapping project was performed on the 1:10,000 scale in the northern Amerini Mts. (Narni–Amelia Ridge, Central Apennines), coupled with facies analysis and multidisciplinary outcrop characterisation. This project was focused on the Jurassic-Lower Cretaceous succession, in order to reconstruct the Mesozoic palaeogeography and tectono-sedimentary evolution of the study area. This sector of the Apenninic Chain (i.e. Umbria-Marche-Sabina palaeogeographic domain) experienced the Early Jurassic rifting phase, which dismembered the vast Calcare Massiccio carbonate platform. The development of a rugged submarine topography, coupled with drowning of the benthic factories, were the main effects of this normal faulting. The complex submarine physiography, made of structural highs and lows, is highlighted by facies and thickness variations of the Jurassic and Lower Cretaceous deposits. The hangingwall blocks hosted thick (hundreds of metres) pelagic successions, with variable volumes of admixed gravity-flow deposits. These successions onlapped the horst blocks along escarpments, rooted in the rift faults, where the pre-rift Calcare Massiccio was exposed. The tops of footwall blocks (Pelagic Carbonate Platforms or PCPs) were capped by thin (few tens of metres or less), fossil-rich and chert-free, condensed pelagic successions. This rift architecture was evened out at a domain scale in the Early Cretaceous. Successively, Miocene orogenic and Plio-Pleistocene extensional faulting caused uplift and exhumation of the Mesozoic rocks.</p><p>In the study area, geothematic mapping associated with the analysis of basin-margin unconformities and successions revealed a narrow and elongated Jurassic structural high (Mt. Croce di Serra - Mt. Alsicci structural high), surrounded by Jurassic basinal pelagites. The PCP-top condensed succession is not preserved. The chert-rich basinal units rest on the horst-block Calcare Massiccio through unconformity surfaces (palaeoescarpments), as marked by the silicification of the (otherwise chert-free) shallow-water limestone. The onlap successions embed megablocks of Calcare Massiccio (hundreds of metres across), detached from their parent palaeoescarpments. Very thin, condensed deposits form discontinuous veneers on the olistoliths of Calcare Massiccio (epi-olistolith deposits) and are onlapped by younger basin-fill pelagites. The beds surrounding the olistoliths are characteristically bent due to differential compaction, as their (newly acquired) strikes mimic the outline of the stiff objects they were burying.</p><p>Indirect evidence for a Toarcian, post-rift, tectonic pulse can be locally mapped, and is documented by angular unconformities between the Pliensbachian and Toarcian pelagites, as well as by mass-transport deposits found in the Rosso Ammonitico (Toarcian).</p><p>The same goes for millimetric to centimetric neptunian dykes made of Maiolica pelagites cross-cutting the Corniola Fm. (Sinemurian-Pliensbachian). These dykes, coupled with the occurrence of unconformities between Aptian-Albian pelagites (Marne a Fucoidi Fm.) and Lower Jurassic rocks (Calcare Massiccio and Corniola formations), provide evidence for a further Early Cretaceous tectonic phase, recently reported from the southern sectors of Narni-Amelia ridge.</p>

The Middle Triassic marine reptile biodiversity in the Germanic Basin, in the centre of the Pangaean world

2012 ◽  
Vol 4 (1) ◽  
Author(s):  
Cajus Diedrich
Keyword(s):  
Middle Triassic ◽  
Coastal Areas ◽  
Skeletal Remains ◽  
Southern Germany ◽  
Shallow Marine ◽  
Germanic Basin ◽  
Marine Reptiles ◽  
Marine Habitats ◽  
Reptile Species ◽  
Marine Reptile

AbstractThe Middle Triassic fossil reptile localities near Bayreuth (Bavaria, southern Germany) consist of shallow marine autochthonous glauconitic marls and terebratulid-rich tempestite carbonates of the newly defined Bindlach and Hegnabrunn formations. Single bones and incomplete skeletons of marine reptiles have been recorded in bone beds within in the Illyrian and Fassanian stages. These include the remains of the sauropterygians Neusticosaurus sp., Lariosaurus cf. buzzii [1], Nothosaurus mirabilis [2], Paranothosaurus giganteus [2], Placodus gigas [3], Cyamodus rostratus [4], Cyamodus münsteri [5], Pistosaurus longaevus [6], and ichthyosaursOmphalosaurus sp., and Shastasaurus sp. or proterosaur Tanystrophaeus conspicuus [7]. New skeletal reconstructions are based on the osteological analysis of three dimensionally preserved bones and skeletal remains. The large number of marine endemic placodont macroalgae feeders (P. gigas) in the Bayreuth sites coincides with the presence of invertebrate palaeocommunities that are characteristic of macroalgae meadow paleoenvironments. Most of the reptile species and genera from the Bayreuth localities also occur in beds of similar ages from the Monte San Giorgio (Switzerland/Italy) or Perledo (Italy) lagoonal areas. Ichthyosaurs and pistosaurs were adapted for open marine conditions, and may have migrated from the Panthalassa Oceans into the shallow marine Germanic Basin to reproduce, whereas placodonts and many other sauropterygians seem to have lived permanently in those shallow marine habitats, with large squamates and thecodont or smaller archosaurs in coastal areas.

Maastrichtian marine reptiles of the Mediterranean Tethys: a palaeobiogeographical approach

2012 ◽  
Vol 183 (6) ◽  
pp. 573-596 ◽  
Author(s):  
Nathalie Bardet
Keyword(s):  
New Jersey ◽  
Northern Margin ◽  
Marine Reptiles ◽  
Global Comparison ◽  
The Mediterranean ◽  
And Cluster Analysis ◽  
Marine Reptile ◽  
Warm Temperate ◽  
Relative Scarcity ◽  
Southern Tethys

AbstractA global comparison of coeval Maastrichtian marine reptiles (squamates, plesiosaurs, chelonians and crocodyliformes) of Europe, New Jersey, northwestern Africa and Middle-East has been performed. More than twenty outcrops and fifty species (half of them being mosasaurids) have been recorded. PEA and Cluster Analysis have been performed using part of this database and have revealed that marine reptile faunas (especially the mosasaurid ones) from the Mediterranean Tethys are clearly segregated into two different palaeobiogeographical provinces: 1) The northern Tethys margin province (New Jersey and Europe), located around palaeolatitudes 30-40°N and developping into warm-temperate environments, is dominated by mosasaurid squamates and chelonioid chelonians; it is characterized by the mosasaurid association of Mosasaurus hoffmanni and Prognathodon sectorius. 2) The southern Tethys margin province (Brazil and the Arabo-African domain), located between palaeolatitudes 20°N-20°S and developping into intertropical environments, is dominated by mosasaurid squamates and bothremydid chelonians; it is characterized by the mosasaurid association of Globidens phosphaticus as well as by Halisaurus arambourgi and Platecarpus (?) ptychodon (Arabo-African domain). These faunal differences are interpreted as revealing palaeoecological preferences probably linked to differences in palaeolatitudinal gradients and/or to palaeocurrents.On a palaeoecological point on view and concerning mosasaurids, the mosasaurines (Prognathodon, Mosasaurus, Globidens and Carinodens) prevail on both margins but with different species. The ichthyophageous plioplatecarpines Plioplatecarpus (Northern margin) and Platecarpus (?) ptychodon (Southern margin) characterise respectively each margin. The halisaurine Halisaurus is present on both margins but with different species. Of importance, the tylosaurines remain currently unknown on the southern Tethys margin and are restricted to higher palaeolatitudes. Chelonians (bothremydids and chelonioids) are respective of each margin, which probably indicates lower dispersal capabilities compared to mosasaurids. The relative scarcity of plesiosaurs and crocodyliformes could be linked to different ecological preferences. The noteworthy crocodyliforme diversity increase in the Palaeogene is probably linked to mosasaurid extinction during the biological crisis of the K/Pg boundary.

scholarly journals An injured pachypleurosaur (Diapsida: Sauropterygia) from the Middle Triassic Luoping Biota indicating predation pressure in the Mesozoic

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Qiling Liu ◽  
Tinglu Yang ◽  
Long Cheng ◽  
Michael J. Benton ◽  
Benjamin C. Moon ◽  
...  
Keyword(s):  
Middle Triassic ◽  
Large Body ◽  
Morphological Characters ◽  
Predation Pressure ◽  
The Body ◽  
West China ◽  
Marine Reptiles ◽  
Large Predator ◽  
The Right ◽  
Marine Reptile

AbstractThe Middle Triassic Luoping Biota in south-west China represents the inception of modern marine ecosystems, with abundant and diverse arthropods, fishes and marine reptiles, indicating recovery from the Permian–Triassic mass extinction. Here we report a new specimen of the predatory marine reptile Diandongosaurus, based on a nearly complete skeleton. The specimen is larger than most other known pachypleurosaurs, and the body shape, caniniform teeth, clavicle with anterior process, and flat distal end of the anterior caudal ribs show its affinities with Diandongosaurus acutidentatus, while the new specimen is approximately three times larger than the holotype. The morphological characters indicate that the new specimen is an adult of D. acutidentatus, allowing for ontogenetic variation. The fang-like teeth and large body size confirm it was a predator, but the amputated hind limb on the right side indicate itself had been predated by an unknown hunter. Predation on such a large predator reveals that predation pressure in the early Mesozoic was intensive, a possible early hint of the Mesozoic Marine Revolution.

scholarly journals Eggs for breakfast? Analysis of a probable mosasaur biting trace on the Cretaceous echinoid <i>Echinocorys ovata</i> Leske, 1778

Fossil Record ◽  
2018 ◽  
Vol 21 (1) ◽  
pp. 55-66 ◽  
Author(s):  
Christian Neumann ◽  
Oliver Hampe
Keyword(s):  
Food Webs ◽  
Prey Selection ◽  
Indirect Evidence ◽  
Northern Germany ◽  
Predator Prey ◽  
Tooth Position ◽  
Oral Surface ◽  
Marine Reptile ◽  
Skeletal Regeneration ◽  
Shed Light

Abstract. Fossil biting traces (praedichnia) represent indirect evidence of predation and shed light on fossil predator–prey interactions and fossil food webs. Especially from echinoderm skeletons, biting traces are well known. Here, we describe the oral surface of a large Cretaceous (Maastrichtian) holasteroid echinoid Echinocorys ovata Leske, 1778 from Hemmoor (northern Germany) which exhibits four circular punctures arranged in a semi-circular arc. Whereas three of the punctures penetrated the skeleton, one puncture only just hit the margin of the echinoid test at the ambitus, leaving a long incision furrow in the skeleton. The punctures were not lethal to the sea urchin as is indicated by progressed skeletal regeneration and closure of the fractures. The overall appearance of the punctures suggests that they were produced during a single mechanical event, most likely by the biting action of the teeth of a large vertebrate animal. We analysed the shape and arrangement of the biting trace and conclude that it was probably produced by a marine reptile possessing a prognath tooth position, most likely by a globidensine mosasauroid. Our finding not only sheds light on mosasaur feeding behaviour and prey selection but also increases the knowledge of the food webs in the chalk sea ecosystem during the uppermost Cretaceous.

Swimming capabilities of Mesozoic marine reptiles: implications for method of predation

Paleobiology ◽  
1988 ◽  
Vol 14 (2) ◽  
pp. 187-205 ◽  
Author(s):  
Judy A. Massare
Keyword(s):  
Swimming Speed ◽  
Teleost Fish ◽  
Body Shape ◽  
Total Drag ◽  
Marine Reptiles ◽  
Major Factors ◽  
Marine Reptile

Body shape and mode of swimming were major factors that affected the swimming capabilities of Mesozoic marine reptiles. By estimating the total drag and the amount of energy available through metabolism, the maximum sustained swimming speed was calculated for 115 marine reptile specimens. Calculated sustained swimming speeds range from 1.8 to 2.7 m/sec, but are probably too high by as much as a factor of two. Mesozoic marine reptiles were probably much slower than modern toothed whales. The diversification of fast, agile teleost fish in the Cretaceous may have therefore contributed to the decline of the marine reptiles.Long-bodied reptiles appear to have had slower sustained swimming speeds than deep-bodied forms of the same length. For a given length, ichthyosaurs were probably faster sustained swimmers than plesiosaurs, and plesiosaurs were probably faster sustained swimmers than crocodiles and mosasaurs. This suggests that the long-bodied forms probably used an ambush technique to capture prey, to maximize the range of possible prey and to minimize competition with the faster pursuit predators.

Short Note: Second Jurassic marine reptile from the Antarctic Peninsula

2008 ◽  
Vol 21 (2) ◽  
pp. 169-170 ◽  
Author(s):  
Daniel C.H. Hikuroa
Keyword(s):  
Antarctic Peninsula ◽  
Short Note ◽  
Marine Reptiles ◽  
Neuquen Basin ◽  
The Rich ◽  
Neuquén Basin ◽  
Marine Reptile ◽  
The Antarctic

Except for the rich record from the Neuquen Basin (e.g. Gasparini & Fernández 2006), Jurassic southern Gondwanan marine reptiles are relatively rare. A tooth discovered in the Bean Peaks, Ellsworth Land, Antarctic Peninsula (Fig. 1) represents the southernmost, and only the second record of Jurassic marine reptiles from the Antarctic Peninsula. Comprising a single, incomplete tooth, the specimen is unable to be assigned to a species, but the paucity of Gondwanan Jurassic marine reptile material means this find adds significant palaeobiogeographical information.

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