Informacja

Drogi użytkowniku, aplikacja do prawidłowego działania wymaga obsługi JavaScript. Proszę włącz obsługę JavaScript w Twojej przeglądarce.

English (EN)·Polski (PL)·Yкраїнський (UK)
Przejdź do strony domowej biblioteki Centralna Biblioteka Wojskowa Link otwiera się w nowym oknie Logo biblioteki Prolib Integro - strona głównaCentralna Biblioteka Wojskowa

Wyszukujesz frazę "ammonoid" wg kryterium: Wszystkie pola

  Lista filtrów
Wyrównaj
    Wyświetlanie 1-15 z 15
    Tytuł:
    The origin of ammonoid locomotion
    Autorzy:
    Klug, C
    Korn, D.
    Powiązania:
    https://bibliotekanauki.pl/articles/21156.pdf
    Data publikacji:
    2004
    Wydawca:
    Polska Akademia Nauk. Instytut Paleobiologii PAN
    Tematy:
    phylogenesis
    Bactritida
    ontogenesis
    Ammonoidea
    conch
    coiling
    Devonian
    paleontology
    locomotion
    ammonoid
    Opis:
    Evolution of the coiled ammonoid conch from the uncoiled bactritid conch was probably coupled with changes in manoeuvrability and swimming velocity. The gradual transformation of uncoiled to coiled ammonoid conchs has essential functional consequences. The radical change in conch geometry during phylogeny but also in ontogeny of early ammonoids implies a shift of the aperture from an original roughly downward, via a downward oblique and an upward oblique to an upward orientation, presuming a neutrally buoyant condition of the ammonoid animal. Similar trends were reconstructed for the three main ammonoid lineages in the Middle Devonian, the agoniatitid, the anarcestid, and the tornoceratid lineages. This allowed an increase in manoeuvrability and in the maximum horizontal swimming speed.
    Źródło:
    Acta Palaeontologica Polonica; 2004, 49, 2
    0567-7920
    Pojawia się w:
    Acta Palaeontologica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Devonian pearls and ammonoid-endoparasite co-evolution
    Autorzy:
    De Baets, K.
    Klug, C.
    Korn, D.
    Powiązania:
    https://bibliotekanauki.pl/articles/23478.pdf
    Data publikacji:
    2011
    Wydawca:
    Polska Akademia Nauk. Instytut Paleobiologii PAN
    Tematy:
    Algeria
    Ammonoidea
    Devonian
    Germany
    Morocco
    Trematoda
    paleontology
    parasite
    pearl
    evolution
    terminology
    distribution
    ammonoid
    endoparasite
    Opis:
    Raised shell projections on the inner shell walls that form pits on the internal moulds of Devonian ammonoids have been known for several decades. New specimens from Morocco reveal novel details of these structures; most, if not all, of which consist of a capsule of ammonoid shell that covers tiny tubes attached to the outer (= lateral or ventral) shell wall from the inside. In accordance with comparable Recent occurrences of similar structures in molluscs, we use the term “pearls” for these structures and the pits they form on the internal moulds. The nature of these encapsulated tubes is described and discussed. Because of the presence of these tubes inside the pearls, pearl arrangement, and their similarity to Recent mollusc occurrences, the tubes are interpreted as traces of parasitoses. The pearls and pits were grouped into five types based on differences in morphology, size, and arrangement. Then, having used these traits to perform a simple cladistic analysis, the resulting cladogram was compared to the phylogeny of ammonoids. Based on this comparison, it appears likely that the parasites underwent a co−evolution with the ammonoids, which lasted 10 to 15 Ma. Patterns of evolutionary events include co−speciation, “drowning on arrival” (end of parasite lineage near base of a new host clade), and “missing the boat” (parasite lineage does not adapt to a new host clade, thus not evolving a new parasite clade). Because of the lack of fossilised soft tissue, only speculations can be made about the systematic affiliation of the parasites, their life−cycle, infection strategy, and ecological framework. Some co−occurring bivalves also have pits reminiscent to structures caused by trematodes in Recent forms. Based on the available information, the tubes are interpreted as artefacts of trematode infestations, which, if correct, would extend the fossil record of parasitic trematodes into the Early Devonian.
    Źródło:
    Acta Palaeontologica Polonica; 2011, 56, 1
    0567-7920
    Pojawia się w:
    Acta Palaeontologica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Differential preservation of the Upper Cretaceous ammonoid Anagaudryceras limatum with corrugated shell in Central Hokkaido, Japan
    Autorzy:
    Wani, R
    Powiązania:
    https://bibliotekanauki.pl/articles/21872.pdf
    Data publikacji:
    2007
    Wydawca:
    Polska Akademia Nauk. Instytut Paleobiologii PAN
    Tematy:
    Hokkaido
    fossil record
    Japan
    Ammonoidea
    Cretaceous
    Upper Cretaceous
    paleoecology
    Anagaudryceras limatum
    corrugation
    paleontology
    ammonoid
    Opis:
    The taphonomy of the Upper Cretaceous ammonite Anagaudryceras limatum differs from associated ammonites in the same horizon. This differential taphonomy is reconstructed based on fragmentation patterns and structural property of the corrugated shells of their body chamber parts. The characteristic preservation of isolated body chamber parts with corrugations is commonly observed in A. limatum from the upper Turonian of the Oyubari area, central Hokkaido, Japan. This preservation probably results from the differential internal structural properties of the hollow body chamber and septated phragmocone as well as the peculiar corrugation on body chamber of the present species: (1) fracturing along the corrugations against bending force is easier than flat material, because of the concentration of force on the tops or bottoms of corrugations, and (2) high durability against compressive forces. The separated body chamber parts were resistant to being squashed and broke into pieces due to the durability of corrugations against compressive force. The statistic test on the fossil assemblage suggests that selective destruction did not affect the fidelity of species composition and relative abundance of the studied fossil assemblage. Molluscan death assemblages in marine systems consistently show strong fidelity to relative abundances in the live community, suggesting that there was an Anagaudryceras−dominant ammonoid community during the late Turonian in the Oyubari area.
    Źródło:
    Acta Palaeontologica Polonica; 2007, 52, 1
    0567-7920
    Pojawia się w:
    Acta Palaeontologica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Double alignments of ammonoid aptychi from the Lower Cretaceous of Southeast France: Result of a post-mortem transport or bromalites?
    Autorzy:
    Reboulet, S
    Rard, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/21005.pdf
    Data publikacji:
    2008
    Wydawca:
    Polska Akademia Nauk. Instytut Paleobiologii PAN
    Tematy:
    Cretaceous
    Valanginian
    predation
    coprolite
    ammonoid
    paleontology
    taphonomy
    France
    aptychus
    Ammonoidea
    Lower Cretaceous
    Opis:
    A new preservation of aptychi is described from the Valanginian limestone−marl alternations of the Vergol section (Drôme), located in the Vocontian Basin (SE France). Aptychi are arranged into two parallel rows which are generally 50 mm in length and separated by 4 mm. The alignments are very often made by entire aptychi (around 10 mm in length), oriented following their harmonic margin. Aptychi show the outside of valve to the viewer: they are convex−up. This fossilization of aptychi is successively interpreted as the result of post−mortem transport by bottom currents (taphonomicresedimentation process) or the residues (bromalites: fossilized regurgitation, gastric and intestinal contents, excrement) from the digestive tract of an ammonoid−eater (biological processes). Both the parallel rows of aptychi are more likely interpreted as a coprolite (fossil faeces) and they could be considered as both halves (hemi−cylindrical in shape) of the same cylindrical coprolite which would have been separated in two parts (following the long axis) just after the animal defecated. Considering this hypothesis, a discussion is proposed on the hypothetical ammonoid−eater responsible for them.
    Źródło:
    Acta Palaeontologica Polonica; 2008, 53, 2
    0567-7920
    Pojawia się w:
    Acta Palaeontologica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Emergence and collapse of the Frasnian conodont and ammonoid communities in the Holy Cross Mountains, Poland
    Autorzy:
    Dzik, J
    Powiązania:
    https://bibliotekanauki.pl/articles/21673.pdf
    Data publikacji:
    2002
    Wydawca:
    Polska Akademia Nauk. Instytut Paleobiologii PAN
    Tematy:
    Ammonoidea
    paleobiology
    Conodonta
    Polska
    collapse
    population variability
    conodont
    community
    Frasnian
    change
    Devonian
    evolution
    Holy Cross Mountains
    paleontology
    ammonoid
    Opis:
    The dominant factor in faunal succession of conodonts in the Frasnian of Poland is the apparent immigration of species originating allopatrically in other regions. Each immigration event usually changes the population variability of a local species (character displacement). Only a few lineages show their phyletic evolution within the studied area. Attempts to distinguish conodont species on the basis of platform element shape failed in some of the latest Frasnian palmatolepidids. Even at the apparatus−based generic level, certain ramiform elements of the apparatus appear much more diagnostic than the platforms. Correlative value of the late Frasnian palmatolepidids of unknown apparatus structure is thus questionable. The evolution of platform elements in Ancyrodella offers a more solid basis for age determination although their great population variability makes resolution rather low and requires the population approach. The panderodontids Belodella(?) tenuiserrata sp., B. minutidentata sp. nov., B. robustidentata sp. nov., prioniodontid Icriodus kielcensis sp. nov., enigmatic monospecific Playfordiidae fam. nov., prioniodinids Dyminodina planidentata gen. et sp. nov., D. anterodenticulata sp. nov., D. kovalensis sp. nov., Pluckidina kielcensis gen. et sp. nov., P. slupiensis sp. nov., P. robustipegmata sp. nov., and P. lagoviensis sp. nov., derived polygnathid Avignathus bifurcatus sp. nov., probably secondarily simplified polygnathid Nicollidina gen. nov., and palmatolepidids Kielcelepis gen. nov., Lagovilepis gen. nov. and Klapperilepis gen. nov. are proposed.
    Źródło:
    Acta Palaeontologica Polonica; 2002, 47, 4
    0567-7920
    Pojawia się w:
    Acta Palaeontologica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Palaeobiogeographic and evolutionary meaning of an early Late Tournaisian ammonoid fauna from the Tafilalt of Morocco
    Autorzy:
    Korn, D
    Bockwinkel, J.
    Ebbighausen, V.
    Klug, C.
    Powiązania:
    https://bibliotekanauki.pl/articles/20107.pdf
    Data publikacji:
    2003
    Wydawca:
    Polska Akademia Nauk. Instytut Paleobiologii PAN
    Tematy:
    Carboniferous
    Ammonoide
    ammonoid fauna
    Morocco
    distribution
    Late Tournaisian
    paleobiogeography
    paleontology
    Tournaisian
    Opis:
    An early Late Tournaisian (Early Carboniferous/Mississippian) ammonoid fauna is described from the Tafilalt of south−eastern Morocco. Twelve genera, four of which are new, and eleven new species are represented: Becanites africanus sp. nov., Triimitoceras epiwocklumeriforme gen. et sp. nov., Irinoceras minutum sp. nov., Muensteroceras quadriconstrictum sp. nov., Eurites bouhamedensis sp. nov., Ouaoufilalites ouaoufilalensis gen. et sp. nov., Helicocyclus fuscus sp. nov., Pericyclus mercatorius sp. nov., Orthocyclus(?) sp., Bouhamedites enigmaticus gen. et sp. nov., Winchelloceras antiatlanteum sp. nov., and Progoniatites maghribensis gen. et sp. nov. Palaeogeographic analysis of Late Tournaisian ammonoid assemblages shows strong endemism at the species−level, but genera and families had a nearly global distribution in the equatorial seas. The new fauna contains the stratigraphically oldest known representatives of the important Carboniferous goniatite families Girtyoceratidae and Goniatitidae.
    Źródło:
    Acta Palaeontologica Polonica; 2003, 48, 1
    0567-7920
    Pojawia się w:
    Acta Palaeontologica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Dimorphism in tetragonitid ammonoid Tetragonites minimus from the Upper Cretaceous in Hokkaido, Northern Japan
    Autorzy:
    Aiba, D.
    Powiązania:
    https://bibliotekanauki.pl/articles/31341368.pdf
    Data publikacji:
    2022
    Wydawca:
    Polska Akademia Nauk. Instytut Paleobiologii PAN
    Tematy:
    paleontology
    dimorphism
    tetragonitid
    ammonoid
    Ammonoidea
    Tetragonidae
    Tetragonites minimus
    Cretaceous
    Upper Cretaceous
    Hokkaido
    Japan
    Źródło:
    Acta Palaeontologica Polonica; 2022, 67, 4; 949-961
    0567-7920
    Pojawia się w:
    Acta Palaeontologica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Hydrodynamically controlled anagenetic evolution of Famennian goniatites from Poland
    Autorzy:
    Niechwedowicz, M
    Trammer, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/22390.pdf
    Data publikacji:
    2007
    Wydawca:
    Polska Akademia Nauk. Instytut Paleobiologii PAN
    Tematy:
    environment change
    Famennian
    hydrodynamics
    Ammonoidea
    Polska
    Devonian
    evolution
    Holy Cross Mountains
    Tornoceratidae
    paleontology
    fossil animal
    ammonoid
    Opis:
    This paper reports on the evolution of ammonoids belonging to the family Tornoceratidae from the Devonian of Janczyce in the Holy Cross Mountains, Poland. Steady and gradual changes in conch morphology of the goniatite lineage Phoenixites frechi–Tornoceras subacutum–T. sublentiforme occurred in concert with water shallowing during the deposition of the Lower Famennian cephalopod limestone. Biometric analysis of ammonoid conch and facies analysis of the cephalopod limestones have been applied to assess the possible relationship between shell geometry and environmental changes. Results show that ratios of whorl width / diameter as well as whorl width / whorl height decreased, while distance from the venter to the greatest whorl width / diameter increased with time, thereby reducing hydrodynamic drag of the shells, probably in response to increasing water turbulence. The interpretation presented here is in agreement with similar cases from the literature. However, this kind of environmentally controlled evolution has hitherto been recognized only in Jurassic and Cretaceous ammonoids. Conch morphology may be considered as an indicator of palaeobathymetry.
    Źródło:
    Acta Palaeontologica Polonica; 2007, 52, 1
    0567-7920
    Pojawia się w:
    Acta Palaeontologica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Dorsal shell wall in ammonoids
    Autorzy:
    Kulicki, C
    Tanabe, K.
    Landman, N.H.
    Mapes, R.H.
    Powiązania:
    https://bibliotekanauki.pl/articles/20686.pdf
    Data publikacji:
    2001
    Wydawca:
    Polska Akademia Nauk. Instytut Paleobiologii PAN
    Tematy:
    dorsal wall
    Ammonoidea
    biomineralization
    dorsal shell
    Sibirites
    body organ
    Aconeceras
    shell wall
    paleontology
    ultrastructure
    wrinkle layer
    ammonoid
    paleozoology
    Subolenekites
    Opis:
    In ammonoids, a soft body organ (possibly a supracephalicmantle fold), extending from the conch aperture secreted aragonitic wrinkles, forming a layer on the surface of the preceding whorl. The dorsal shell wall consists of the outer and inner components which were deposited sequentially, beginning at the aperture of the living chamber inwards. The dorsal wall attains its full thickness near the last septum. The outer component is visible in the apertural region and is smooth or wrinkled; it is called the wrinkled layer in the latter case. The wrinkles may be continuous, interrupted, or form isolated patches arranged in rows. The wrinkles are usually triangular in cross section. A further stage of dorsal wall development involves filling in the space between the apices of triangles, and then adding one or more inner prismatic layers from the inside of the living chamber. This pattern occurs at least in the postembryonic stage of all genera studied, belonging to five suborders of Ammonoidea ranging from Late Carboniferousto Late Cretaceous. In many genera, the outer component of the dorsal shell wall exhibits remarkable ontogenetic change in its ultrastructure and microornament. It may be compared with the black film of Recent Nautilus shells with respect to place of formation. The outer component of the ammonoid dorsal shell wall is regarded as a product of organic secretion and carbonate precipitation in the area of the supracephalic mantle fold.
    U planispiralnie skręconych amonoidów, u których ścianka grzbietowa styka się bezpośrednio ze ścianką poprzedniego skrętu, mamy do czynienia z modyfikacją strukturalną ścianki grzbietowej w obszarze styku obu ścianek. Wymienione modyfikacje dotyczą w głównej mierze zewnętrznego składnika ścianki grzbietowej tzw. wrinkle-layer, położonego bezpośrednio na peryostrakum poprzedniego skrętu. Strefa zmarszczek (wrinkle-layer) znana była początkowo jedynie u amonoidów paleozoicznych, dopiero Senior (1971) i Kulicki (1979) odnotowali jej występowanie u amonoidów mezozoicznych. Na podstawie przebadanego materiału obejmującego 12 rodzajów należących do pięciu podrzędów Ammonoidea i występujących od późnego paleozoiku do późnej kredy nie stwierdzono występowania strefy zmarszczek poza ścianką grzbietową. Podobne suuktury, obserwowane u paleozoicznych amonoidów w ściankach bocznej i brzusznej nosza nazwę „Ritzstreifen” i nie są homologiczne do zmarszczek „wrinkle-layer”. Typowa zmarszczka „wrinkle-layer” w przekroju podłuznym zbudowana jest z elementu centralnego, organicznego lub organo-mineralnego, oraz pryzmatycznych warstewek, w których długie osie pryzm są prostopadłe do boków trójkąta skierowanych do wnętrza komory mieszkalnej. Obok typowych elementów strefy zmarszczek, opisano tzw. elementy dwurożne o zarysie okrągłym, lub owalnym u triasowych rodzajów Subolenekites i Sibirites, a także u wczesnokredowego Aconeceras. Te elementy były błędnie interpretowane (Doguzhaeva & Mutvei 1986) jako pory związane z przyczepami miękkich tkanek płaszcza do muszli. Typowa strefa zmarszczek wytwarzana przez fałd nadgłowowy płaszcza, została stwierdzona we wszystkich badanych podrzędach za wyjątkiem Phylloceratina. W wymienionym rzędzie opisano powszechnie występujące rytmiczne modyfikacje peryostrakum wbudowywane do ścianki grzbietowej. We wczesnych stadiach rozwojowych modyfikacje te mogą przypominać elementy strefy zmarszczek, lecz ich pochodzenie i budowa są różne.
    Źródło:
    Acta Palaeontologica Polonica; 2001, 46, 1
    0567-7920
    Pojawia się w:
    Acta Palaeontologica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Low durophagous predation on Toarcian (Early Jurassic) ammonoids in the northwestern Panthalassa shelf basin
    Autorzy:
    Takeda, Y.
    Tanabe, K.
    Powiązania:
    https://bibliotekanauki.pl/articles/23068.pdf
    Data publikacji:
    2015
    Wydawca:
    Polska Akademia Nauk. Instytut Paleobiologii PAN
    Tematy:
    Toarcian
    Early Jurassic
    Jurassic
    ammonoid
    Panthalassa zob.Panthalassic Ocean
    Panthalassic Ocean
    shelf basin
    Ammonoidea
    predation
    ventral bite mark
    paleontology
    Opis:
    Predatory shell breakage is known to occur occasionally on the ventrolateral portion of the body chamber in Mesozoic ammonoids. Here we report, for the first time, quantitative data of shell breakage in large ammonoid samples that were recovered from the lower Toarcian (Lower Jurassic) strata in the Toyora area, western Japan. The strata yielding the ammonoid samples consisted mostly of well-laminated, bituminous black shale that was deposited in an oxygen-depleted shelf basin of the northwestern Panthalassa, under the influence of the early Toarcian oceanic anoxic event. Among a total of 1305 specimens from 18 localities, apparent shell breakage was recognised in 35 specimens belonging to 7 genera, resulting in only a 2.7% frequency of occurrence relative to the total number of specimens. The breakage occurs mostly on the ventrolateral side of the body chamber with a complete shell aperture. This fact, as well as the low energy bottom condition suggested for the ammonoid-bearing shale, indicate that the shell breaks observed in the examined ammonoids were not produced by non-biological, post-mortem biostratinomical processes but were lethal injuries inflicted by nek-tonic predators such as reptiles, jawed fishes, coleoids, nautiloids, and carnivorous ammonoids with calcified rostral tips in their upper and lower jaws. Similar predatory shell breaks on the ventrolateral side of the body chamber have been found in contemporaneous ammonoid assemblages of the Tethys Realm, with a much higher frequency of occurrence than in the examined samples from the northwestern Panthalassa, suggesting a weaker durophagous predation pressure on ammonoids in the latter bioprovince.
    Źródło:
    Acta Palaeontologica Polonica; 2015, 60, 4
    0567-7920
    Pojawia się w:
    Acta Palaeontologica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Precursory siphuncular membranes in the body chamber of Phyllopachyceras and comparisons with other ammonoids
    Autorzy:
    Tanabe, K
    Kulicki, C.
    Landman, N.H.
    Powiązania:
    https://bibliotekanauki.pl/articles/22378.pdf
    Data publikacji:
    2005
    Wydawca:
    Polska Akademia Nauk. Instytut Paleobiologii PAN
    Tematy:
    Ammonoidea
    Late Cretaceous
    organic membrane
    scanning electron microscopy
    morphogenesis
    Hokkaido
    body chamber
    Japan
    chamber formation
    Phyllopachyceras ezoense
    septal epithelium
    paleontology
    Phyllopachyceras
    ammonoid
    Opis:
    Organic membranes preserved in the rear part of the body chamber of the Late Cretaceous phylloceratid ammonite Phyllopachyceras ezoense were examined with scanning electron microscopy (SEM) on the basis of well−preserved specimens from Hokkaido, Japan. SEM observations revealed that the membranes are continuous with the siphuncular tube wall in the phragmocone and consist of two layers, both of which are made of a dark, primarily conchiolin material; namely, a thinner inner homogeneous layer and a thicker outer layer with gently inclined pillar−like units. Hence, they are interpreted as the precursory siphuncular membranes. The precursory siphuncular membranes are not associated with any other organic components such as the siphuncular sheets reported in some Paleozoic and Mesozoic ammonoids. Unlike the tube−like condition in the phragmocone, the precursory siphuncular membranes in the body chamber of the specimens examined do not form a tube shape; on the ventral side the membranes are truncated and directly contact the outer shell wall. These observations suggest that the inner and outer layers of the precursory siphuncular membranes in the body chamber were respectively formed by the siphuncular epithelium from the inner side and by the invaginated septal epithelium from the outer side. It is also postulated that at the initial stage of septal formation, the rear part of the body moved slowly forward, developing a circumsiphonal invagination of the septal epithelium. Because similar conchiolin membranes are occasionally preserved in the body chambers of other phylloceratids, the above morphogenetic process applies to all members of the Phylloceratina. The tube−shaped structure in the rear part of the body chamber of desmoceratid Damesites consists only of nacreous layer. We interpret it as a pathologically overgrown prochoanitic septal neck.
    Źródło:
    Acta Palaeontologica Polonica; 2005, 50, 1
    0567-7920
    Pojawia się w:
    Acta Palaeontologica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Piggyback whorls: A new theoretical morphologic model reveals constructional linkages among morphological characters in ammonoids
    Autorzy:
    Ubukata, T
    Tanabe, K.
    Shigeta, Y.
    Maeda, H.
    Mapes, R.H.
    Powiązania:
    https://bibliotekanauki.pl/articles/20269.pdf
    Data publikacji:
    2008
    Wydawca:
    Polska Akademia Nauk. Instytut Paleobiologii PAN
    Tematy:
    morphospace
    morphology
    morphological data
    fossil animal
    constructional linkage
    ammonoid
    paleontology
    cross-sectional shape
    computer simulation
    shell growth
    morphological diversity
    Opis:
    A new theoretical morphological model is proposed for the analysis of growth, form and morphospace of ammonoid shells. In this model, the shape of a radial cross section through the shell is simulated by “piggybacking” of successive whorls. The “piggyback whorls model” is defined in terms of the enlarging rate of the perimeter and the proportion of the dorsal wall to the whorl periphery, if an isometric relationship is assumed between perimeter and area of the cross−sectioned whorl. Allometric coefficients on these growth parameters determine how compressed and evolute shells are formed. The present model successfully reproduced some correlations among purely geometric variables that have been reported in previous works and were also observed in our biometric analyses. This model yields a hypothesis of “constructional linkages” between aperture shape and coiling geometry that might provide a functional coupling between hydrostatic and hydrodynamic characters. The model may partly explain Buckman’s Law of Covariation between rib features and shell shapes.
    Źródło:
    Acta Palaeontologica Polonica; 2008, 53, 1
    0567-7920
    Pojawia się w:
    Acta Palaeontologica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Lower and Middle Jurassic ammonoids of the Shemshak Group in Alborz, Iran and their palaeobiogeographical and biostratigraphical importance
    Autorzy:
    Seyed-Amami, K
    Fursich, F.T.
    Wilmsen, M.
    Majidifard, M.R.
    Shekarifard, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/21183.pdf
    Data publikacji:
    2008
    Wydawca:
    Polska Akademia Nauk. Instytut Paleobiologii PAN
    Tematy:
    Middle Jurassic
    biostratigraphy
    Lower Jurassic
    Ammonitida
    ammonoid
    paleontology
    Jurassic
    Alborz Mountains
    paleobiogeography
    Shemshak Group
    Iran
    Opis:
    The Shemshak Group at Shahmirzad (northern Iran) is characterized by the most frequent and extensive marine intercalations and contains the most abundant and diverse ammonite faunas hitherto known from the Lower and lower Middle Jurassic strata of the Alborz Range. So far, 62 ammonite taxa have been recorded from this area, including 25 taxa from earlier studies. The taxa belong to the families Cymbitidae, Echioceratidae, Amaltheidae, Dactylioceratidae, Hildoceratidae, Graphoceratidae, Hammatoceratidae, Erycitidae, and Stephanoceratidae with the new species Paradumortieria elmii and Pleydellia (P.?) ruttneri. The fauna represents the Late Sinemurian, Late Pliensbachian, Toarcian, Aalenian, and Early Bajocian. Palaeobiogeographically, it is closely related to the Northwest European (Subboreal) Province, and exhibits only minor relations with the Mediterranean (Tethyan) Province.
    Źródło:
    Acta Palaeontologica Polonica; 2008, 53, 2
    0567-7920
    Pojawia się w:
    Acta Palaeontologica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Extreme abundance of ammonoids in mass accumulations from the Late Devonian of the Moroccan Anti-Atlas
    Autorzy:
    Greif, M.
    Nebelsick, J.H.
    Klug, C.
    Powiązania:
    https://bibliotekanauki.pl/articles/31341387.pdf
    Data publikacji:
    2022
    Wydawca:
    Polska Akademia Nauk. Instytut Paleobiologii PAN
    Tematy:
    paleontology
    paleoecology
    ammonoid
    mass accumulation
    biomass
    Cephalopoda
    Ammonoidea
    fecundity
    Famennian
    Devonian
    Late Devonian
    Morocco
    Anti-Atlas Mountains
    Lesser Atlas Mountains zob.Anti-Atlas Mountains
    Little Atlas Mountains zob.Anti-Atlas Mountains
    Atlas Mountains
    Źródło:
    Acta Palaeontologica Polonica; 2022, 67, 3; 667-684
    0567-7920
    Pojawia się w:
    Acta Palaeontologica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-15 z 15

      Ta witryna wykorzystuje pliki cookies do przechowywania informacji na Twoim komputerze. Pliki cookies stosujemy w celu świadczenia usług na najwyższym poziomie, w tym w sposób dostosowany do indywidualnych potrzeb. Korzystanie z witryny bez zmiany ustawień dotyczących cookies oznacza, że będą one zamieszczane w Twoim komputerze. W każdym momencie możesz dokonać zmiany ustawień dotyczących cookies