Wyniki wyszukiwania

1

Artykuł dostępny w postaci pełnego tekstu - kliknij by otworzyć plik

Ammonoid biodiversity changes across the Cenomanian-Turonian boundary in the Yezo Group, Hokkaido, Japan

100%

Kurihara K., Toshimitsu S., Hirano H.

Acta Palaeontologica Polonica

|

2012

|

tom 57

|

nr 4

Ammonoid biodiversity changes from shallow to offshore environments across the Cenomanian–Turonian (C–T) boundary are reconstructed in the Yezo Group, Hokkaido, Japan. This group was probably deposited at approximately 35–45ºN along a westward subduction margin in the northeastern Asian continent. Temporal changes in species richness in the Yezo Group, which show persistently high values during the middle Cenomanian and then decline stepwise from near the middle–late Cenomanian boundary, resemble those in Europe, but not those in Tunisia and the Western Interior. These differences suggest that the Cenomanian–Turonian “mass extinction” was not a global event for ammonoids but was restricted to mid−palaeolatitudinal regions (Europe and Japan). Sea level and climate changes probably influenced ammonoid faunas in the Yezo Group as well as those in Europe. However, it is unlikely that a single, simple cause led to the C–T boundary “mass extinction” because various abiotic changes in the Cenomanian–Turonian transition have been detected, and biotic and abiotic change are interrelated.

2

Lower Turonian record of belemnite Praeactinocamax from NW Siberia and its palaeogeographic significance

100%

Kostak M., Wiese F.

Acta Palaeontologica Polonica

|

2008

|

tom 53

|

nr 4

Specimens of the belemnitellid Praeactinocamax Naidin, 1964 are described from the Upper Cretaceous of NW Siberia (Taimyr Region, Lower Agapa River, Russia). The rostra determined as Praeactinocamax aff. plenus consist of an aragonitic anterior part and a calcitic posterior part with a sharp boundary in between. This boundary surface is referred to as the “alveolar fracture”, and it is a typical morphological feature of early belemnitellids and not a result of diagenetic processes. The occurrence of Praeactinocamax in Arctic areas shows a wider palaeobiogeographical distribution of the genus in the Late Cenomanian–Early Turonian interval than previously known. This finding suggests that migration of the late Cenomanian–early Turonian fauna occurred across Turgai channel. The geographic position of these new records may also explain the occurrence of Praeactinocamax in the Turonian of the US Western Interior Seaway, the origin of which has been hitherto unclear.

3

The oldest African eucryptodiran turtle from the Cretaceous of Angola

100%

Mateus O., Jacobs L., Polcyn M., Schulp A. S., Vineyard D., Buta Neto A., Antunes M. T.

Acta Palaeontologica Polonica

|

2009

|

tom 54

|

nr 4

A new Late Cretaceous turtle, Angolachelys mbaxi gen. et sp. nov., from the Turonian (90 Mya) of Angola, represents the oldest eucryptodire from Africa. Phylogenetic analysis recovers Angolachelys mbaxi as the sister taxon of Sandownia harrisi from the Aptian of Isle of Wight, England. An unnamed turtle from the Albian Glen Rose Formation of Texas (USA) and the Kimmeridgian turtle Solnhofia parsonsi (Germany), are successively more distant sister taxa. Bootstrap analysis suggests those four taxa together form a previously unrecognized monophyletic clade of marine turtles, herein named Angolachelonia clade nov., supported by the following synapomorphies: mandibular articulation of quadrate aligned with or posterior to the occiput, and basisphenoid not visible or visibility greatly reduced in ventral view. Basal eucryptodires and angolachelonians originated in the northern hemisphere, thus Angolachelys represents one of the first marine amniote lineages to have invaded the South Atlantic after separation of Africa and South America.

4

New paleontological data from the Turonian and Coniacian of the Opole Trough (SW Poland)

80%

Niedzwiedzki R., Godlewska A.

Geologia Sudetica

|

2005

|

tom 37

5

Extremely rare Turonian belemnites from the Bohemian Cretaceous Basin and their palaeogeographical importance

80%

Kostak M., Wiese F.

Acta Palaeontologica Polonica

|

2011

|

tom 56

|

nr 2

New records of extremely rare late Turonian belemnites are described from the Úpohlavy working quarry in the Bohemian Cretaceous Basin. These specimens are referred to Praeactinocamax bohemicus (Stolley, 1916). An alveolar fragment possibly represents Praeactinocamax strehlensis (Fritsch, 1872) and would be the third find of this species ever recorded. All finds derive from a thin horizon in the uppermost part of the Hudcov limestone (Teplice Formation, uppermost Subprionocyclus neptuni Ammonite Zone). The small faunule most likely had its origin in a taxon from the Praeactinocamax manitobensis/walkeri/sternbergi group of the North American Province, and its occurrence in Europe can be seen in the context of a southward shift of Boreal taxa in the course of a late Turonian cooling event.

6

Vertebral morphology, dentition, age, growth, and ecology of the large lamniform shark Cardabiodon ricki

80%

Newbrey M. G., Siversson M., Cook T. D., Fotheringham A. M., Sanchez R. L.

Acta Palaeontologica Polonica

|

2015

|

tom 60

|

nr 4

Cardabiodon ricki and Cardabiodon venator were large lamniform sharks with a patchy but global distribution in the Cenomanian and Turonian. Their teeth are generally rare and skeletal elements are less common. The centra of Cardabiodon ricki can be distinguished from those of other lamniforms by their unique combination of characteristics: medium length, round articulating outline with a very thick corpus calcareum, a corpus calcareum with a laterally flat rim, robust radial lamellae, thick radial lamellae that occur in low density, concentric lamellae absent, small circular or subovate pores concentrated next to each corpus calcareum, and papillose circular ridges on the surface of the corpus calcareum. The large diameter and robustness of the centra of two examined specimens suggest that Cardabiodon was large, had a rigid vertebral column, and was a fast swimmer. The sectioned corpora calcarea show both individuals deposited 13 bands (assumed to represent annual increments) after the birth ring. The identification of the birth ring is supported in the holotype of Cardabiodon ricki as the back-calculated tooth size at age 0 is nearly equal to the size of the smallest known isolated tooth of this species. The birth ring size (5-6.6 mm radial distance [RD]) overlaps with that of Archaeolamna kopingensis (5.4 mm RD) and the range of variation of Cretoxyrhina mantelli (6-11.6 mm RD) from the Smoky Hill Chalk, Niobrara Formation. The revised, reconstructed lower jaw dentition of the holotype of Cardabiodon ricki contains four anterior and 12 lateroposterior files. Total body length is estimated at 5.5 m based on 746 mm lower jaw bite circumference reconstructed from associated teeth of the holotype.

7

Paracupes svitkoi [Coleoptera: Cupedidae], a new species from the Cretaceous of New Jersey

80%

Lubkin S. H.

Acta Zoologica Cracoviensia

|

2003

|

tom 46

|

nr Suppl.

Paracupes svitkoi is a new species based on a single specimen from the Raritan Formation of the Cretaceous of New Jersey. The fossil, a well-preserved, charcoalified head, is the first fossil member of the genus Paracupes KOLBE, 1898. It is very similar to the modern species in the genus.

8

Aragonitic rostra of the Turonian belemnitid Goniacamax: arguments from diagenesis

70%

Dauphin Y., Williams C. T., Barskov I. S.

Acta Palaeontologica Polonica

|

2007

|

tom 52

|

nr 1

The hypothesis that belemnitid rostra are formed by primary biogenic low−Mg calcite is widespread. However, the coexistence in the same rostrum of both aragonitic and calcitic components has been reported in true belemnites (Goniocamax, Turonian). A combined microstructural and chemical composition study of the comparison of shells with undisputed mineralogy from the same site as the Turonian Goniocamax, shows that these aragonitic shells display the effects of diagenetic alteration. These observations favour the hypothesis that belemnite rostra are composed of primary aragonite, rather than low−Mg calcite, and are consistent with all other cephalopod shells. Calcitic and aragonitic rostra are also known in other Dibranchiata such as Triassic Aulacocerida and Eocene Belopterina. Diagenetic changes such as shown here may clearly affect palaeo−environmental interpretations based on carbonate shells.

9

New sharks and rays from the Cenomanian and Turonian of Charentes, France

70%

Vullo R., Cappetta H., Neraudeau D.

Acta Palaeontologica Polonica

|

2007

|

tom 52

|

nr 1

New or so far poorly known neoselachians from the Cenomanian and Turonian of SW France are described. The material studied herein comes from nine localities in the Charentes region, comprising palaeoenvironments ranging from coastal to open marine environments, and consists of two orectolobiforms, six lamniforms, and four rajiforms. The new taxa are Squalicorax coquandi sp. nov. and Roulletia bureaui gen. et sp. nov. within lamniforms, and Hamrabatis bernardezi sp. nov., Archingeayia sistaci gen. et sp. nov., and Engolismaia couillardi gen. et sp. nov. within rajiforms. New specimens of Odontaspis rochebrunei Sauvage, 1880 from the type area allow redescription of this taxon, assigned herein to the genus Cenocarcharias. Occurrences of Squalicorax baharijensis, S. cf. intermedius, and Archaeolamna sp., previously unrecorded from this region, and Almascyllium, a genus generally described from younger strata, are also noted, and improve knowledge of mid−Cretaceous selachian faunas from Western Europe.

Ograniczanie wyników

Ammonoid biodiversity changes across the Cenomanian-Turonian boundary in the Yezo Group, Hokkaido, Japan

Lower Turonian record of belemnite Praeactinocamax from NW Siberia and its palaeogeographic significance

The oldest African eucryptodiran turtle from the Cretaceous of Angola

New paleontological data from the Turonian and Coniacian of the Opole Trough (SW Poland)

Extremely rare Turonian belemnites from the Bohemian Cretaceous Basin and their palaeogeographical importance

Vertebral morphology, dentition, age, growth, and ecology of the large lamniform shark Cardabiodon ricki

Paracupes svitkoi [Coleoptera: Cupedidae], a new species from the Cretaceous of New Jersey

Aragonitic rostra of the Turonian belemnitid Goniacamax: arguments from diagenesis

New sharks and rays from the Cenomanian and Turonian of Charentes, France