First records of Somalinautilus (Cephalopoda: Nautiloidea) from the Jurassic of Southern Germany – inferences for trans-provincial migrations

2020 ◽  
Vol 298 (2) ◽  
pp. 137-146
Author(s):  
Günter Schweigert
Keyword(s):  
Sea Level ◽  
Geographic Distribution ◽  
Middle Jurassic ◽  
Late Jurassic ◽  
Southern Germany ◽  
First Time ◽  
Lower Kimmeridgian ◽  
Lower Bathonian

The Late Jurassic nautiloid Somalinautilus antiquus (Dacqué, 1910), previously only known by the holotype from Lower Kimmeridgian strata of Ethiopia, is reported from the Lower Kimmeridgian (Platynota Zone) of Southern Germany. This unexpected record largely expands the known geographic distribution of this species. Another species of Somalinautilus, S. clavifer Tintant , 1994, is recorded for the first time from the Middle Jurassic (Lower Bathonian, Zigzag Zone) of Southern Germany. A short stratigraphic and palaeogeographic review of Somalinautilus occurrences is provided. Faunal migrations of nautiloids over large distances were probably triggered by sea- level highstands and/or palaeocurrents.

scholarly journals Sphenofontis velserae gen. et sp. nov., a new rhynchocephalian from the Late Jurassic of Brunn (Solnhofen Archipelago, southern Germany)

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11363
Author(s):  
Andrea Villa ◽  
Roel Montie ◽  
Martin Röper ◽  
Monika Rothgaenger ◽  
Oliver W.M. Rauhut
Keyword(s):  
Middle Jurassic ◽  
Late Jurassic ◽  
Wide Distribution ◽  
New Taxon ◽  
Skeletal Morphology ◽  
Southern Germany ◽  
Single Well ◽  
History Of

The Solnhofen Archipelago is well known for its fossil vertebrates of Late Jurassic age, among which figure numerous rhynchocephalian specimens, representing at least six and up to nine genera. A new taxon, named Sphenofontis velserae gen. et sp. nov., increases rhynchocephalian diversity in the Solnhofen Archipelago and is herein described based on a single, well-preserved specimen originating from the Late Kimmeridgian of the Brunn quarry, near Regensburg. The exquisite preservation of the holotype allowed a detailed description of the animal, revealing a skeletal morphology that includes both plesiomorphic and derived features within rhynchocephalians. Sphenofontis is herein referred to Neosphenodontia and tentatively to sphenodontine sphenodontids. It notably differs from all other rhynchocephalians known from the Jurassic of Europe, showing instead closer resemblance with the Middle Jurassic Cynosphenodon from Mexico and especially the extant Sphenodon. This is evidence for a wide distribution of taxa related to the extant tuatara early in the Mesozoic, and also for the presence of less-specialized rhynchocephalians coexisting with more derived forms during the earliest time in the history of the Solnhofen Archipelago.

Note preliminaire sur le Bathonien inferieur du Bugey (Jura meridional)

1964 ◽  
Vol S7-VI (4) ◽  
pp. 529-534
Author(s):  
Charles Mangold ◽  
R. Enay ◽  
Pierre Dominjon
Keyword(s):  
Geographic Distribution ◽  
Middle Jurassic ◽  
Western Europe ◽  
Jura Mountains ◽  
Southern England ◽  
Upper Bajocian ◽  
Relationship Of ◽  
The Relationship ◽  
Lower Bathonian

Abstract The recent discovery of lower Bathonian (upper middle Jurassic) ammonites at several places in the Bugey region of the southern Jura mountains of eastern France resolves the problem of the relationship of the Bajocian to the Bathonian in this key region. Fauna of upper Bajocian (lower middle Jurassic) and middle and upper Bathonian had long been known but lower Bathonian was unknown. One bed is particularly rich in a varied fauna of ammonites, pelecypods, gastropods, and echinoderms in a remarkable state of preservation. The faunal association shows the coexistence of the forms of the Zigzag beds of England and the Wuerttembergicus beds of Germany, thus confirming the homology of these two horizons. The geographic distribution of type genera of the lower Bathonian in western Europe permits the identification of two faunal domains overlapping in Lorraine and the northern Jura mountains as well as the Bugey region. The genus Zigzagiceras extends from southern England through Switzerland, the Jura mountains, and the Basses-Alpes to Sicily, and also has been found in Portugal. The western limit of the species Parkinsonia (Oraniceras) wuerttembergica occurs in Germany, Lorraine, the Jura mountains, and Sicily. It appears that the genera Morphoceras and Ebrayiceras may have an even greater distribution.

Kimmeridgian and early Tithonian cephalopods from the Kisújbánya Limestone Formation, Zengővárkony (Mecsek Mountains, southern Hungary), their faunal composition, palaeobiogeographic affinities, and taphonomic character

2021 ◽  
Vol 21 (13) ◽  
pp. 265-314
Author(s):  
László Bujtor ◽  
Richárd Albrecht ◽  
Csaba Farkas ◽  
Bertalan Makó ◽  
Dávid Maróti ◽  
...  
Keyword(s):  
Late Jurassic ◽  
First Record ◽  
Internal Mould ◽  
Weathering Processes ◽  
Shell Fragment ◽  
Long Time ◽  
First Time ◽  
Upper Kimmeridgian ◽  
Ammonite Zones ◽  
Lower Kimmeridgian

A new collection at Zengővárkony (Mecsek Mountains, Hungary) provided a rich and diverse but poorly preserved cephalopod-dominated fossil assemblage representing the Kimmeridgian and the lower Tithonian. The material came from mixed scree, soil, and amongst roots affected by weathering processes having been exposed to the elements for a long time. The nautiloid Pseudaganides strambergensis is the first record from the Mecsek Mountains. Due to the weathering, the ammonite fauna consists of mainly fragmentary and dissolved individuals that comprises 528 specimens belonging to 34 species and 30 genera out of which 20 species and 15 genera are reported for the first time from the Mecsek Mountains. The fauna includes specimens of known taxa. No new taxa are introduced. Based on the comparison with other faunas, this assemblage most closely resembles the fauna of the Venetian Alps (Italy). Additional faunal elements include aptychi (Laevaptychus latus, Lamellaptychus murocostatus), belemnites (Hibolithes semisulcatus), and an indetermined brachiopod. The first record of Spiraserpula spirolinites, an encrusting fossil polychaete preserved on the internal mould of a Taramelliceras shell fragment indicates favourable bottom conditions for the epifauna. The presence of Aspidoceras caletanum, Gravesia aff. gigas, and Pseudowaagenia inerme indicates faunal connections with the Submediterranean Province of the Tethys, which is in line with the tectonic and palaeogeographical position of the Mecsek Zone during the Late Jurassic. The ammonite assemblage represents elements of five Tethysian ammonite zones of the Kimmeridgian and Tithonian. The lower Kimmeridgian Herbichi Zone is indicated by Streblites tenuilobatus and Praesimoceras herbichi. The upper Kimmeridgian Acanthicum Zone is indicated by Aspidoceras acanthicum, and the Cavouri Zone by Mesosimoceras cavouri and Aspidoceras caletanum. The upper Kimmeridgian Beckeri Zone is suggested by Hybonoticeras pressulum and Pseudowaagenia inerme. Whereas Gravesia aff. gigas, Lithacoceras aff. siliceum, and Malagasites? denseplicatus are faunal elements characterising the Early Tithonian Hybonotum Zone. Phylloceratid and lytoceratid specimens account only for 12% of the fauna, while the majority of the specimens belong to the Oppeliidae and Ataxioceratidae (60%).

scholarly journals Jurassic

1982 ◽  
Vol 8 ◽  
pp. 37-45
Author(s):  
Jens Ole Koch ◽  
Lise Holm ◽  
Olaf Michelsen
Keyword(s):  
Sea Level ◽  
North Sea ◽  
Middle Jurassic ◽  
Late Jurassic ◽  
Main Part ◽  
Early Jurassic ◽  
The North ◽  
The North Sea ◽  
Sand Bodies

During Early Jurassic time, deposition continued in the basinal areas occupied by Triassic sedimentation. The Danish Central Graben subsided strongly and more than 4000 m of sediments were deposited during Jurassic time (fig. 14). North of the area the thickness seems less than 2000 m and, in the Norwegian-Danish Basin, approximately 1200 m. The rhythm of sedimentation corresponds closely to what is known from adjacent areas in the Northwest European sedimentary region. During the Early Jurassic, relatively uniform marine claystone series, the Fjerritslev Formation, were deposited all over the North Sea region, including the main part of the highs. Large areas were uplifted and eroded during the Mid Cimmerian phase (fig. 23), accompanied by a general eustatic lowering of the sea level. During the Middle Jurassic period, deltaic or fluvial conditions prevailed in the main part of the North Sea, and coal-bearing sand bodies, the J-2 Unit, were deposited. During the Late Jurassic a general subsidence took place, but more restricted areas were transgressed by the sea than in the Early Jurassic. Thick marine claystone series (the J-3 and J-4 Units) were deposited in the main part of the basin. Near marginal highs, only minor sand bodies (the W-1 Unit) were laid down. The Late Jurassic is a period of main subsidence for the Central Graben. Figs. 21 and 23 show the distribution of Jurassic sediments.

scholarly journals Bone histology of the Middle Jurassic turtle shell remains from Kirtlington, Oxfordshire, England

2017 ◽  
Author(s):  
Torsten M. Scheyer ◽  
Jérémy Anquetin
Keyword(s):  
Cortical Bone ◽  
Phylogenetic Relationships ◽  
Middle Jurassic ◽  
Late Jurassic ◽  
Bone Histology ◽  
Histological Structure ◽  
Turtle Shell ◽  
Fibre Bundles ◽  
First Time ◽  
New Evidence

The Middle Jurassic (Bathonian) turtle material from the Mammal Bed at Kirtlington, Oxfordshire, England, has recently been tentatively referred to the Pleurosternidae, although the known synapomorphies of this clade were absent from the specimens. Here we present new evidence from shell bone histology that corroborates reports of pleurosternids at Kirtlington and further reveal that two different histomorphs (= two different taxa) are present in this locality. The first histomorph presents the distinctive histological structure of pleurosternids, which is described herein for the first time: the external cortical bone layers are differentiated into an inner zone of coarse, irregularly interwoven structural fibre bundles and an outer fine-fibred zone. The second histomorph has a more plesiomorphic structure and can only be assigned to Cryptodira indet. A morphological reassessment of the Kirtlington material fails to recognize two different taxa and shows that only sparse evidence supports the presence of pleurosternids in this locality. Shell bone histology thus appears as a powerful tool to study poorly preserved specimens and may in some case (like with pleurosternids) help resolve phylogenetic relationships. According to our results, the stratigraphic appearance of the Pleurosternidae is adjusted from the Kimmeridgian (Late Jurassic) to the Bathonian (Middle Jurassic), which significantly reduces the ghost lineage of Paracryptodira.

Radiolarian assemblages of Middle and Late Jurassic to early Late Cretaceous (Cenomanian) ages from an olistolith record pelagic deposition within the Bornova Flysch Zone in western Turkey

2012 ◽  
Vol 183 (4) ◽  
pp. 307-318 ◽  
Author(s):  
Ugur Kagan Tekin ◽  
M. Cemal Göncüoglu ◽  
Seda Uzuncimen
Keyword(s):  
Late Cretaceous ◽  
Middle Jurassic ◽  
Late Jurassic ◽  
Western Turkey ◽  
Oceanic Basin ◽  
Platform Margin ◽  
Lowermost Part ◽  
Early Late ◽  
Radiolarian Assemblages

Abstract The Bornova Flysch Zone (BFZ) in NW Anatolia comprises several olistoliths or tectonic slivers, representing various parts of the Izmir-Ankara ocean. Radiolarian assemblages extracted from one of the olistoliths of the BFZ, cropping out along the Sögütlü section, to the NE Manisa city, were studied in detail. The lowermost part of the section contains latest Bajocian – early Callovian radiolarian taxa, followed by radiolarian assemblages indicating Late Jurassic to early Late Cretaceous (Cenomanian) ages. Previous studies reveal that the Izmir-Ankara oceanic basin was initially opened during late Ladinian – early Carnian. The new radiolarian data obtained from this olistolith reveals that relatively condensed, and possibly more or less continuous, pelagic sedimentation took place during the late Middle Jurassic to early Late Cretaceous in a non-volcanic oceanic basin closer to the Tauride-Anatolide platform margin.

Modes of extinction, pseudo-extinction and distribution in Middle Jurassic ammonites: terminology

2001 ◽  
Vol 38 (2) ◽  
pp. 187-195
Author(s):  
Gerd EG Westermann
Keyword(s):  
New Species ◽  
Sea Level ◽  
Middle Jurassic ◽  
Small Populations ◽  
Sea Level Changes ◽  
Range Contraction ◽  
Extreme Form ◽  
Phylogenetic Lineage

Mid-Jurassic Ammonitina (Cephalopoda, Mollusca) provide good examples of true and apparent "extinctions" (i.e., taxon or clade disappearances) at the local, regional, and global scales. A terminology is presented. Extinction is the termination of a phylogenetic lineage or entire clade (not of local demes or regional populations). Extinction was often preceded by progressive range contraction that resulted in diachronous regional disappearance ("extirpation") and occurred with the elimination of the last refuge. Other range contractions, however, were not terminal, but were followed by renewed expansions, resulting in temporary absence of the lineage over part of its known range only, due to pseudo-extinction. Some lineages, called Lazarus taxa, apparently disappeared entirely for short or extended periods by pseudotermination (causing a "phylogenetic hiatus"). This is an extreme form of pseudo-extinction with unknown refuge due to small size and (or) unsuitable facies and location. Lineage or clade reappearance may be in the form of new species, whose relationship to ancestral taxa has been problematic. Some disappearances can be explained with displacive competition, where the replacement taxon is either of endemic origin or an immigrant. Recent research in previously underexplored field areas has closed some of the gaps of documentation by finding the refuges. Range contractions and expansions, together with their regional disappearances and pseudo-extinctions, including pseudotermination, were often causally related to sea-level changes, especially eustasy. Most true extinctions, however, cannot be identified precisely, because they occurred in small populations and (or) refuges. Extinctions presumably did not coincide with global geoevents.

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