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Tytuł:
A new euselachian shark from the early Permian of the Middle Urals, Russia
Autorzy:
IVANOV, ALEXANDER O.
DUFFIN, CHRISTOPHER J.
NAUGOLNYKH, SERGE V.
Powiązania:
https://bibliotekanauki.pl/articles/945229.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
chondrichthyes
elasmobranchii
teeth
permian
russia
urals
Opis:
The isolated teeth of a new euselachian shark Artiodus prominens Ivanov and Duffin gen. et sp. nov. have been found in the Artinskian Stage (Early Permian) of Krasnoufimskie Klyuchiki quarry (Sverdlovsk Region, Middle Urals, Russia). The teeth of Artiodus possess a multicuspid orthodont crown with from four to nine triangular cusps; prominent labial projection terminating in a large round tubercle; distinct ornamentation from straight or recurved cristae; oval or semilunar, elongate, considerably vascularized base; dense vascular network formed of transverse horizontal, ascending, short secondary and semicircular canals. The teeth of the new taxon otherwise most closely resemble the teeth of some protacrodontid and sphenacanthid euselachians possessing a protacrodont-type crown, but differ from the teeth of all other known euselachians in the unique structure of the labial projection. The studied teeth vary in crown and base morphology, and three tooth morphotypes can be distinguished in the collection reflecting a moderate degree of linear gradient monognathic heterodonty. The range of morphologies otherwise displayed by the collection of teeth shows the greatest similarity to that described for the dentitions of relatively high-crowned hybodontids from the Mesozoic. The internal structure of the teeth, including their vascularization system is reconstructed using microtomography. The highest chondrichthyan taxonomic diversity is found in the Artinskian, especially from the localities of the Middle and South Urals.
Źródło:
Acta Palaeontologica Polonica; 2017, 62, 2; 290-298
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A probable oligochaete from an Early Triassic Lagerstatte of the southern Cis-Urals and its evolutionary implications
Autorzy:
Shcherbakov, D.E.
Timm, T.
Tzetlin, A.B.
Vinn, O.
Zhuravlev, A.Y.
Powiązania:
https://bibliotekanauki.pl/articles/2082181.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Annelida
Clitellata
Oligochaeta
Mesozoic
Lagerstätte
Russia
Opis:
Oligochaetes, despite their important role in terrestrial ecosystems and a tremendous biomass, are extremely rare fossils. The palaeontological record of these worms is restricted to some cocoons, presumable trace fossils and a few body fossils the most convincing of which are discovered in Mesozoic and Cenozoic strata. The Olenekian (Lower Triassic) siliciclastic lacustrine Petropavlovka Lagerstätte of the southern Cis-Urals yields a number of extraordinary freshwater fossils including an annelid. The segmented body with a secondary annulation of this fossil, a subtriangular prostomium, a relatively thick layered body wall and, possibly, the presence of a genital region point to its oligochaete affinities. Other fossil worms which have been ascribed to clitellates are reviewed and, with a tentative exception of two Pennsylvanian finds, affinities of any pre-Mesozoic forms to clitellate annelids are rejected. The new fossil worm allows tracing of a persuasive oligochaete record to the lowermost Mesozoic and confirms a plausibility of the origin of this annelid group in freshwater conditions.
Źródło:
Acta Palaeontologica Polonica; 2020, 65, 2; 219-233
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New diplodocoid sauropod dinosaur material from the Middle Jurassic of European Russia
Autorzy:
Averianov, A.O.
Zverkov, N.G.
Powiązania:
https://bibliotekanauki.pl/articles/2082206.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Dinosauria
Sauropoda
Diplodocoidea
Mesozoic
Russia
Fennoscandian landmass
Opis:
Two anterior caudal vertebrae from apparently a single individual from the Callovian (Middle Jurassic) marine deposits of the Podosinki Formation at Peski Quarry near Moscow, Russia, are attributed by the phylogenetic analyses of two independent datasets to the sauropod clade Diplodocoidea. Morphologically, these vertebrae differ from the anterior caudals of Diplodocidae and Rebbachisauridae, but are similar to those of Dicraeosauridae. This finding is in line with a recent discovery of the dicraeosaurid sauropod Lingwulong from the late Early–early Middle Jurassic of China, and suggests earlier diversification of the main neosauropod lineages and Asiatic origin for Dicraeosauridae. The Peski sauropod is the first Jurassic terrestrial vertebrate from the Fennoscandian landmass. Diplodocoid sauropods likely dispersed to this land massive before the Bathonian, when it was still connected with Asia.
Źródło:
Acta Palaeontologica Polonica; 2020, 65, 3; 499-509
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The soft-tissue attachment scars in Late Jurassic ammonites from Central Russia
Autorzy:
Mironenko, A.A.
Powiązania:
https://bibliotekanauki.pl/articles/22288.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Ammonoidea
Craspeditidae
Kachpurites
Garniericeras
soft tissue attachment
attachment scar
Late Jurassic
Jurassic
ammonite
paleobiology
Central Russia
Russia
Opis:
Soft-tissue attachment scars of two genera and four species of Late Jurassic craspeditid ammonites from the Russian Platform are described. A previously suggested relationship between lateral attachment scars and ammonoid hyponome is confirmed, however, a new interpretation is proposed for dorsal attachment scars: they could have been areas not only for attachment of the dorsal (nuchal) retractors, but also of the cephalic retractors. The new type of the soft-tissue attachment—anterior lateral sinuses, located between the lateral attachment scars and the aperture of the ammonite body chamber is described. Enclosed elliptical or subtriangular areas in apertural parts of the anterior lateral sinuses were found for the first time. Their presence and location suggest that this structure could have been used for attaching the funnel-locking apparatus, similar to those of coleoids. A transformation of shape and position of lateral attachment scars through the evolution of the Late Jurassic craspeditid lineage starting from platycones (Kachpurites fulgens) to keeled oxycones (Garniericeras catenulatum) is recognized.
Źródło:
Acta Palaeontologica Polonica; 2015, 60, 4
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new type of shell malformation caused by epizoans in Late Jurassic ammonites from Central Russia
Autorzy:
MIRONENKO, ALEKSANDR A.
Powiązania:
https://bibliotekanauki.pl/articles/945743.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
ammonoidea
craspeditidae
kachpurites
parasites
epifauna
jurassic
russia
Opis:
A new type of shell damage on Late Jurassic ammonite Kachpurites fulgens is described. The new type of shell malformation consists of small elongated pits, arranged in groups on the surface of ammonite shell and concentrated near the terminal aperture. The examination of the pits demonstrated no signs of drilling, biting, or healing of punctures. The shell layers in the pits are bent downward without changing in thickness. At the same time the pits, in some cases, significantly distort the shape of the shell walls. Deformed growth lines are associated with some of the pits. All of this supports the hypothesis that the pits had been formed by epifauna located at a flexible uncalcified part of the periostracum in the apertural region of the growing ammonite shell. It is likely that epizoan attachment led to the deformation of the thin periostracum film and to the distortion of the growing shell wall. The nature of epizoans is discussed, but remains unclear due to their rather poor preservation. The relationship between epizoans and ammonites is also an open question: they could have been parasites, but other types of biotic relationships cannot be entirely ruled out.
Źródło:
Acta Palaeontologica Polonica; 2016, 61, 3; 645-660
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Feeding convergence among ray-finned fishes: Teeth of the herbivorous actinopterygians from the latest Permian of East European Platform, Russia
Autorzy:
Pindakiewicz, M.
Talanda, M.
Sulej, T.
Niedźwiedzki, G.
Sennikov, A.G.
Bakaev, A.S.
Bulanov, V.V.
Golubev, V.K.
Minikh, A.V.
Powiązania:
https://bibliotekanauki.pl/articles/2082138.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Actinopterygii
Eurynotoidiidae
multicuspid teeth
herbivory
convergence
Permian
Russia
Opis:
A unique functional adaptation to herbivory within early ray-finned fishes is exemplified by the late Permian actinopterygians within the family Eurynotoidiidae with policuspid teeth strongly modified with respect to the primitive actinopterygian conditions. Here we report additional finds of multidenticulated teeth from the fluvial latest Permian deposits of Russia. The teeth belong to the members of endemic Eurynotoidiidae and show rather high morphological diversity. We confirm that the Russian forms are the earliest known ray-finned fishes with substantial modifications of teeth adapted to the processing of food. These finds confirm some previous suggestions that the adaptation to herbivory first developed in freshwater fishes, not marine. We found very similar dental adaptations in some groups of Recent freshwater teleosts, especially in characiforms and cichlids. It suggests that sympatric species of Permian Eurynotoidiidae explored various herbivorous niches like modern fish in East African lakes. Apparently, this first pulse of adaptive radiation in ray-finned fishes was probably caused by diversification of Permian aquatic vertebrate community.
Źródło:
Acta Palaeontologica Polonica; 2020, 65, 1; 71-79
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Femoral histology and growth patterns of the ceratopsian dinosaur Psittacosaurus sibiricus from the Early Cretaceous of Western Siberia
Autorzy:
Skutschas, P.P.
Morozov, S.S.
Averianov, A.O.
Leshchinskiy, S.V.
Ivantsov, S.V.
Fayngerts, A.V.
Feofanova, O.A.
Vladimirova, O.N.
Slobodin, D.A.
Powiązania:
https://bibliotekanauki.pl/articles/2082328.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Dinosauria
Ceratopsia
Psittacosaurus
bone histology
Cretaceous
Siberia
Russia
Opis:
The early ceratopsian dinosaur Psittacosaurus sibiricus from the Early Cretaceous of Western Siberia, Russia, is one of the most advanced and largest (up to 2.5 m) members of the genus. Here we present a description of ontogenetic changes in the long-bone histology of this species. Analysis of a growth series of femora demonstrates significant histological maturation during ontogeny, expressed by the progressive appearance of signs of bone remodeling (erosion bays, secondary bone formation), decreasing of vascularity, changing of the orientation of vascular canals from reticular to longitudinal, and appearance of parallel-fibred bone in the outer part cortex. These ontogenetic changes in the longbone histology of P. sibiricus are generally similar to those of another relatively advanced species, P. lujiatunensis from China. The basal P. mongoliensis from Mongolia shows less mature long-bone histology during late ontogeny (e.g., the late appearance of signs of remodeling and the predominance of reticular vascularization at later stages). We suggest that the earlier achievement of histological maturity is an evolutionary trend of the genus Psittacosaurus.
Źródło:
Acta Palaeontologica Polonica; 2021, 66, 2; 437-447
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An enigmatic early ? palaeocope ostracode from the Arenig of NW Russia
Autorzy:
Tinn, O
Meidla, T.
Powiązania:
https://bibliotekanauki.pl/articles/22806.pdf
Data publikacji:
2002
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
systematic position
ostracod
Ordovician
Russia
Ostracoda
paleontology
Lavachilina evae
Opis:
The ostracode Lavachilina evae gen. et sp. nov. is described from the Arenig of Western Russia. Its carapace possesses a unique discontinuous velum, developed at both ends as a narrow spinose ridge. The systematic position of L. evae is uncertain. Its character set shows mostly palaeocope affinities but also some features of leiocopes. L. evae is tentatively assigned to the palaeocope family Oepikellidae, possibly representing an early member of that family. Although L. evae existed contemporaneously with palaeocopes such as Laccochilina, it does not appear to be closely related to these early eurychilinoids.
Źródło:
Acta Palaeontologica Polonica; 2002, 47, 4
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A review of Neogene and Quaternary pikes of southeastern Europe and a new species from the early Pleistocene of Nogaisk, Ukraine
Autorzy:
KOVALCHUK, OLEKSANDR M.
WILSON, MARK V.H.
GRANDE, TERRY
Powiązania:
https://bibliotekanauki.pl/articles/945423.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
: esociformes
esocidae
esox
miocene
pliocene
pleistocene
ukraine
russia
moldova
Opis:
The fish genus Esox (Teleostei, Esocidae) has been recorded from thirty late Miocene, Pliocene, and Pleistocene localities where forty-one bone-bearing strata are exposed in the territory of Ukraine, Russian Federation, and Republic of Moldova. From eight localities the genus is reported or described for the first time. A detailed description and morphological analysis of the currently available osteological material demonstrates the presence of four species in the studied area: (i) Esox sibiricus (late Miocene–early Pliocene); (ii) Esox moldavicus (early Pliocene–early Pleistocene); (iii) Esox nogaicus sp. nov. (early Pleistocene, Calabrian); (iv) Esox lucius (early–middle Pleistocene). The Northern Pike (Esox lucius) is recorded for the first time in the early Pleistocene fossil record of southeastern Europe. The new species E. nogaicus is characterized by a massive dentary with deep symphysis and the possible presence of a pair of fixed canine-like teeth near the anterior end of the vomer. Such canine teeth are seen also in certain species known only from North America, the extant Esox masquinongy, the fossil species E. columbianus, and an unnamed Miocene form. However, unlike in E. nogaicus, in the three North American species fixed canines also occur anteriorly on the palatines. The Miocene, Pliocene, and Pleistocene pikes from southeastern Europe document a greater diversity of morphologies in the past than exists today in the pike species of Europe. Changes in the predominant species of Esox in southeastern Europe are hypothesized to be driven by changing global and regional climates.
Źródło:
Acta Palaeontologica Polonica; 2017, 62, 1; 121-135
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new assessment of the Late Devonian antiarchan fish Bothriolepis leptocheira from South Timan (Russia) and the biotic crisis near the Frasnian–Famennian boundary
Autorzy:
LUKŠEVIČS, ERVĪNS
BEZNOSOV, PAVEL
STŪRIS, VALDEMĀRS
Powiązania:
https://bibliotekanauki.pl/articles/945315.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
placodermi
diversity
variability
devonian
frasnian
famennian
russia
south timan
Opis:
The species of the Late Devonian, earliest Famennian placoderm fish Bothriolepis jeremejevi has been downranked to subspecies Bothriolepis leptocheira jeremejevi comb. nov. in a result of detailed morphological studies of the type specimens and abundant new material from the type locality of the Sosnogorsk Formation, South Timan, Komi Republic, Russia. This taxon closely resembles Bothriolepis leptocheira leptocheira from Scotland, B. leptocheira curonica from Latvia, and B. leptocheira ssp. from Severnaya Zemlya differing only in small deviations of the size, proportions and shape of some plates of the armour. The composition of vertebrate assemblages from Scotland, Latvia, and Severnaya Zemlya containing B. leptocheira demonstrates a reduced diversity of antiarch placoderm, acanthodian, and sarcopterygian fishes; however, the Sosnogorsk assemblage differs in a larger diversity containing very primitive tetrapod and diversified sarcopterygian fishes including dipnoans and porolepiforms but lacking acanthodians. Wide distribution of a single species of Bothriolepis and usually diminished diversity of vertebrates suggest that the earliest Famennian vertebrate assemblages conform the survival faunas of the latest Frasnian–earliest Famennian biotic crisis.
Źródło:
Acta Palaeontologica Polonica; 2017, 62, 1; 97-119
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cenozoic fossil fishes of the extinct alepisauroid family Polymerichthyidae from the Sakhalin Island, Russia
Autorzy:
NAZARKIN, MIKHAIL V.
Powiązania:
https://bibliotekanauki.pl/articles/945438.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
teleostei
aulopiformes
polymerichthys
morphological analysis
systematics
tertiary
russia
sakhalin
Opis:
Five incomplete skeletons of fishes of the extinct monotypic family Polymerichthyidae (Aulopiformes: Alepisauroidei) from the Paleogene and Neogene of Sakhalin Island, Russia, are identified as Polymerichthys sp., described in detail, and compared with known representatives of the family. The results of this study suggest that polymerichthyids were characterized by a prolonged rostrum, behind which the upper jaw symphysis was placed; by an anal fin without spinules, contrary to what was assumed earlier; and, probably, by sexual dimorphism. Morphological analysis reveals the closest relationships of Polymerichthyidae to be with Recent Alepisauridae, but their taxonomic position is still unresolved. The new material is the second occurrence of articulated skeleton of fishes of this family. The new findings from Sakhalin expand the known geographical distribution of Pacific polymerichthyids by about 12° of latitude, and extend the time interval for this family to as early as the late Oligocene.
Źródło:
Acta Palaeontologica Polonica; 2016, 61, 4; 829-838
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Alpha taxonomy of the Russian Permian procolophonoid reptiles
Autorzy:
Saila, L.K.
Powiązania:
https://bibliotekanauki.pl/articles/22010.pdf
Data publikacji:
2009
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
taxonomy
Russia
Permian
procolophonoid reptile
Procolophonoidea
Parareptilia
Procolophonidae
paleobiogeography
Opis:
European Russia has been the source of many procolophonoid taxa from both the Permian and Triassic, and a Permian origin for the procolophonoid family Procolophonidae has been based on the Russian taxon Microphon exiguus. Recently, this taxon was reclassified as a seymouriamorph and, in its place, the taxa Nyctiphruretus, Suchonosaurus, and Kinelia from the Middle and Upper Permian of Russia were suggested as “procolophons”, using evolutionary−systematic classification methods. In recent phylogenies, however, Nyctiphruretus has been recovered as a non–procolophonoid parareptile, whereas Kinelia and Suchonosaurus have never been included in a phylogenetic study. Re−examination indicates that Suchonosaurus is a member of the procolophonoid subfamily Procolophonidae based on the shape of the maxillary bone and the external naris, the laterally visible maxillary depression, and the number and type of maxillary teeth. Kinelia, on the other hand, is excluded from the Procolophonoidea because of its subpleurodont dental attachment and lack of any procolophonoid features. Thus, Suchonosaurus is the only confirmed Permian procolophonid from the Permian of Russia. Additionally, re−examination of the holotype of Microphon exiguus confirms that it is identical to the seymouriamorph specimens recently included in the genus Microphon and that it lacks procolophonoid features. The earliest unequivocal record of the subfamily Procolophonidae is confirmed from the Late Permian of Russia, making Russia the only region where, with certainty, both Permian and Triassic procolophonids have been discovered.
Źródło:
Acta Palaeontologica Polonica; 2009, 54, 4
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Concentrations of Silurian nautiloid cephalopods from Russia and Kazakhstan
Autorzy:
Bogolepova, O K
Holland, C H
Powiązania:
https://bibliotekanauki.pl/articles/22316.pdf
Data publikacji:
1995
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Cephalopoda
cephalopod
Silurian
concentration
Russia
living population
Kazakhstan
paleontology
nautiloid cephalopod
Opis:
Silurian cephalopod limestones known from northern Asia are usually singular beds or horizons of nodules. They range in their taphonomic character from the Mojero river type, with postmortem concentration from rich living populations by relatively gentle bottom currents into a submarine low, to that of the Karabutak Formation of the South Urals, where there has been concentration by strong wave or current action.
Źródło:
Acta Palaeontologica Polonica; 1995, 40, 4
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Femur of a morganucodontid mammal from the Middle Jurassic of Central Russia
Autorzy:
Gambaryan, P P
Averianov, A.O.
Powiązania:
https://bibliotekanauki.pl/articles/23231.pdf
Data publikacji:
2001
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Morganucodontidae
Middle Jurassic
mammal
anatomy
Mammalia
morganucodontid
Russia
femur
Jurassic
locomotion
Opis:
We describe a nearly complete mammalian femur from the Middle Jurassic (upper Bathonian) from Peski quarry, situated some 100 km south east of Moscow, central Russia. It is similar to the femora of Morganucodontidae in having a globular femoral head, separated from the greater trochanter and reflected dorsally, fovea capitis present, both trochanters triangular and located on the same plane, distal end flat, mediolaterally expanded, and somewhat bent ventrally, and in the shape and proportions of distal condyles. It is referred to as Morganucodontidae gen. et sp. indet. It is the first representative of this group of mammals in Eastern Europe from the third Mesozoic mammal locality discovered in Russia. Exquisite preservation of the bone surface allowed us to reconstruct partial hind limb musculature. We reconstruct m. iliopsoas as inserting on the ridge, which starts at the lesser trochanter and extends along the medial femoral margin for more than half of the femur length. On this basis we conclude that the mode of locomotion of the Peski morganucodontid was similar to that of modern echidnas. During the propulsive phase the femur did not retract and the step elongation was provided by pronation of the femur.
Źródło:
Acta Palaeontologica Polonica; 2001, 46, 1
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Lower Turonian record of belemnite Praeactinocamax from NW Siberia and its palaeogeographic significance
Autorzy:
Kostak, M.
Wiese, F.
Powiązania:
https://bibliotekanauki.pl/articles/21284.pdf
Data publikacji:
2008
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Lower Turonian
belemnite
Praeactinocamax
Siberia
paleogeography
Belemnitellidae
Turonian
Upper Cretaceous
Russia
Opis:
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.
Źródło:
Acta Palaeontologica Polonica; 2008, 53, 4
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
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