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1

Age, distribution, and phylogeny of the peculiar Late Devonian ammonoid Soliclymenia

100%

Korn D. , Niedźwiedzki R. , Posieczek J.

Acta Geologica Polonica

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2005

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tom Vol. 55, no. 2

99-108

EN

New records of the triangularly coiled Soliclymenia paradoxa (MUNSTER, 1839) from Dzikowiec (Sudetes, Poland) allow the study of intraspecific variability. It can be demonstrated that at least three species within the genus Soliclymenia can be separated. The genus has a limited stratigraphic distribution within the .Wocklumeria Stufe. of the Late Devonian, but a wide geographic range within the tropical seas.

2

The dorsal shell wall structure of Mesozoic ammonoids

86%

Acta Palaeontologica Polonica

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2017

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tom 62

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nr 1

EN

The study of pristine preserved shells of Mesozoic Ammonoidea shows different types of construction and formation of the dorsal shell wall. We observe three major types: (i) The vast majority of Ammonoidea, usually planispirally coiled, has a prismatic reduced dorsal shell wall which consists of an outer organic component (e.g., wrinkle layer), which is the first layer to be formed, and the subsequently formed dorsal inner prismatic layer. The dorsal mantle tissue suppresses the formation of the outer prismatic layer and nacreous layer. With the exception of the outer organic component, secretion of a shell wall is omitted at the aperture. A prismatic reduced dorsal shell wall is always secreted immediately after the hatching during early teleoconch formation. Due to its broad distribution in (planispiral) Ammonoidea, the prismatic reduced dorsal shell wall is probably the general state. (ii) Some planispirally coiled Ammonoidea have a nacreous reduced dorsal shell wall which consists of three mineralized layers: two prismatic layers (primary and secondary dorsal inner prismatic layer) and an enclosed nacreous layer (secondary dorsal nacreous layer). The dorsal shell wall is omitted at the aperture and was secreted in the rear living chamber. Its layers are a continuation of an umbilical shell doubling (reinforcement by additional shell layers) that extends towards the ventral crest of the preceding whorl. The nacreous reduced dorsal shell wall is formed in the process of ontogeny following a prismatic reduced dorsal shell wall. (iii) Heteromorph and some planispirally coiled taxa secrete a complete dorsal shell wall which forms a continuation of the ventral and lateral shell layers. It is formed during ontogeny following a prismatic reduced dorsal shell wall or a priori. The construction is identical with the ventral and lateral shell wall, including a dorsal nacreous layer. The wide distribution of the ability to form dorsal nacre indicates that it is a plesiomorphic trait which either was passed on from gyrocone ammonoid ancestors or (re-)developed in post-Triassic ammonoids.

3

The mid-Famennian ammonoid succession in the Rhenish Mountains: the "annulata Event" reconsidered

86%

Korn D.

Geological Quarterly

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2004

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tom Vol. 48, No 3

245--252

EN

The mid-Late Devonian pelagic sedimentary successions of the Rhenish Mountains and other regions show a double black shale horizon called the annulata Black Shale. It marks, at the species level, a prominent faunal turnover of ammonoids from the Prolobites delphinus Zone into the Platyclymenia annulata Zone. An analysis of ammonoid genera distribution, phylogenetic relationships, andmorphospace occupation demonstrates that the "annulata Event" does not correspond to a crisis of the group and does not fulfill the criteria of a major biotic event.

4

Ammonoidea Toarcian biohorizons in the Basque-Cantabrian Basin (N Spain): a correlation between the Iberian Range and the Mediterranean Province standard scale

86%

Goy A. , Martinez G. , Ureta S.

Volumina Jurassica

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2006

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tom Vol. 4, no. 1

166-167

EN

In the Basque-Cantabrian Basin several detailed biostratigraphical studies in Toarcian sediments have been carried out, and all the zones and the most subzones from the NW European Province standard scale have been characterized. Recent investigations allow us to complete the reference scale and define 35 successive ammonoidea biohorizons that can be identified in the whole basin with rare exceptions. Biohorizons have been established with similar criteria to those suggested by Page (1995), and when possible, the evolution of a particular taxonomic group has been taken into account. The use of taxa with an important record overlap in the basin has been avoided. • Tenuicostatum Zone (1 – simplex, 2 – mirabile, 3 – crosbeyi, 4 – tenuicostatum, 5 – semicelatum). Successive species of Dactylioceras with reference sections in Camino (1, 2, 3, 5) and San Miguel de Aguayo (4). • Serpentinus Zone (6 – elegantulum, 7 – exaratum, 8 – elegans, 9 – pseudoserpentinus, 10 – douvillei). Species of Harpoceratinae (Eleganticeras, Cleviceras, Harpoceras) and Hildoceratinae (Orthildaites) with reference sections in Tudanca (6, 7, 8, 9) and San Andrés (10). • Bifrons Zone (11 – sublevisoni, 12 – tethysi, 13 – lusitanicum, 14 – apertum, 15 – bifrons, 16 – semipolitum). Successive species of Hildoceras with reference section in San Andrés. • Variabilis Zone (17 – variabilis, 18 – illustris, 19 – phillipsi, 20 – vitiosa). Species of Haugia with reference section in San Andrés. • Thouarsense Zone (21 – “Grammoceras”, 22 – “Essericeras”, 23 – fallaciosum). The presence of discontinuities in numerous sections and the poor and casual record of Grammoceras and Essericeras, challenging the establishment of the lowers biohorizons in this Zone. Their reference sections are Cillamayor (21, 22) and Castillo Pedroso (23). • Dispansum Zone (24 – cappuccinum, 25 – pachu, 26 – gruneri). The firsts two are successive species of Hammatoceras and the third one is a Gruneria species with a extensive record in the basin. All of them have the reference section in Cillamayor. • Pseudoradiosa Zone (27 – levesquei, 28 – munieri, 29 – pseudoradiosa, 30 – tectiforme). Successive species of Dumortieria and Paradumortieria with reference section in Cillamayor. • Aalensis Zone (31 – mactra, 32 – subcompta, 33 – aalensis/fluitans, 34 – falcifer, 35 – buckmani). Successive species of Pleydellia with reference section in San Andrés. This succession of biohorizons has numerous similarities with the one for the Iberian Range and considerable differences with sucessions from regions further south in the Iberian Peninsula. Moreover, the presence of the same taxa as other W. Tethys regions, where detailed biozonations have been made, enable the establishment of a precise correlation between the Basque-Cantabrian Basin and the Mediterranean Province, for some particular intervals and specifically for the base of Tenuicostatum/ Polymorphum Serpentinus/Levisoni, Bifrons, Dispansum/Speciosum and Aalensis zones. The discontinuous records of Collina gemma and Dumortieria meneghinii provide difficulties in correlation between Variabilis/Gradata, and Pseudoradiosa/Meneghinii zones, respectively. The present knowledge on the Basque-Cantabrian Basin doesn’t allow the precise correlation of the base of Thouarense/Bonarelli Zones.

5

Sanmartinoceras aff. walshense (ETHERIDGE, 1892) from the Early Cretaceous of California - the first evidence of the ammonite subfamily Aconeceratinae SPATH, 1923 in North America

86%

Lehmann J. , Murphy M.

Acta Geologica Polonica

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2000

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tom Vol. 50, no. 1

119-124

EN

Sanmartinoceras aff. walshense (ETHERIDGE, 1892), a single large representative of the Aconeceratinae SPATH, 1923 from California is believed to be a macroconch. It shows close relations to Sanmartinoceras africanum KENNEDY & KLINGER, 1979 and Sanmartinoceras walshense, however the described combination of features is unique. Until the variability of this ammonite is established we assign this specimen to Sanmartinoceras aff. walshense. It is probably Late Aptian in age and represents the first evidence of the Aconeceratinae in North America

6

Aalenian (Jurassic) to Berriasian (Cretaceous) chronostratigraphic zonation and guide ammonites of the Central Andes (Argentina, Chile, Peru)

81%

Parent H.

Volumina Jurassica

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2022

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tom Vol. 20

1--46

EN

In the Central Andes there are developed two marine basins with an extensive Jurassic record: the Neuquén (or Central Andean) Basin and the Tarapacá Basin. Their Jurassic and Lower Cretaceous ammonite successions have been studied extensively for more than 150 years, producing detailed chronostratigraphic scales based on ammonite zones and biohorizons. The ammonite faunas include Andean lineages, and cosmopolitan, Tethyan, Caribbean, North American, and Indo-Madagascan elements. This paper presents the results of a revision of the zonation of the interval Aalenian-Berriasian. Before presenting the results, this paper emphasizes the distinction between, and the convenient nomenclature for, biozones, zones, standard zones, and biohorizons. The scissum Hz. (new) is introduced in the lower (-most?) Manflasensis Zone (Aalenian). The Rotundum Subzone (new) with base at the cf.-leptus Hz., is introduced for the upper part of the Rotundum Zone (Bajocian). The Gulisanoi Zone (Bathonian) is standardized by designation of the cf.-aspidoides Hz. (new) as its base. The Chacaymelehuensis Zone (new) with base at the “prahecquense” Hz. (new) is introduced for the Callovian. The Cubanensis Zone (Oxfordian) is introduced to replace nominally, or to rename, the inconveniently named “Passendorferia” Zone. The Tarapacaense Zone (Oxfordian) is standardized by designation of the tarapacaense Hz. (new) as its base. The Tithonian Malarguensis Zone (formerly subzone) is here emended and standardized by designation of the malarguensis Hz. as its base; this zone replaces the unviable Mendozanus Zone. The Zitteli Zone is standardized by designation of the widely recorded perlaevis Hz. as its base. The Fascipartita Subzone (Internispinosum Zone) is standardized by designation of the internispinosum-beta Hz. (new) as its base. The Alternans Zone is standardized by designation of the vetustum Hz. as its base, and the Koeneni Zone (uppermost Tithonian) by designation of the striolatus Hz. as its base.

7

New and poorly known Perisphinctoidea (Ammonitina) from the Upper Tithonian of Le Chouet (Drôme, SE France)

72%

Bulot L. , Frau C. , Wimbledon W.

Volumina Jurassica

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2014

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tom Vol. 12, no. 1

113--128

EN

The aim of this paper is to document the ammonite fauna of the upper part of the Late Tithonian collected at the key section of Le Chouet (Drôme, SE France). Emphasis is laid on new and poorly known Ataxioceratidae, Himalayitidae and Neocomitidae from the upper part of the Tithonian. Among the Ataxioceratidae, a new account on the taxonomy and relationship between Paraulacosphinctes Schindewolf and Moravisphinctes Tavera is presented. Regarding the Himalayitidae, the range and content of Micracanthoceras Spath is discussed and two new genera are introduced: Ardesciella gen. nov., for a group of Mediterranean ammonites that is homoeomorphic with the Andean genus Corongoceras Spath, and Pratumidiscus gen. nov. for a specimen that shows morphological similarities with the Boreal genera Riasanites Spath and Riasanella Mitta. Finally, the occurrence of Neocomitidae in the uppermost Tithonian is documented by the presence of the reputedly Berriasian genera Busnardoiceras Tavera and Pseudargentiniceras Spath.

8

Short-term survival of ammonites in New Jersey after the end-Cretaceous bolide impact

72%

Landman N. H. , Garb M. P. , Rovelli R. , Ebel D. S. , Edwards L. E.

Acta Palaeontologica Polonica

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2012

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tom 57

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nr 4

EN

A section containing the Cretaceous/Paleogene (= Cretaceous/Tertiary) boundary in Monmouth County, New Jersey, preserves a record of ammonites extending from the end of the Cretaceous into possibly the beginning of the Danian. The section includes the upper part of the Tinton Formation and lower part of the Hornerstown Formation. The top of the Tinton Formation is represented by a richly fossiliferous unit (the Pinna Layer) that contains many bivalves in life position as well as ammonite jaws preserved inside body chambers. Ammonites include Pachydiscus (Neodesmoceras) mokotibensis, Sphenodiscus lobatus, Eubaculites carinatus, E. latecarinatus, Discoscaphites iris, D. sphaeroidalis, D. minardi, and D. jerseyensis. The Pinna Layer probably represents a relatively short interval of time lasting tens to hundreds of years; it is conformably overlain by the Burrowed Unit, which contains a single fragment of Discoscaphites sp. and several fragments of E. latecarinatus, as well as several isolated specimens of ammonite jaws including two of Eubaculites. Examination of the mode of preservation of the ammonites and jaws suggests that they were fossilized during deposition of the Burrowed Unit and were not reworked from older deposits. Based on the ammonites and dinoflagellates in the Pinna Layer and the Burrowed Unit, these strata traditionally would be assigned to the uppermost Maastrichtian, corresponding to calcareous nannofossil Subzone CC26b. However, a weak iridium anomaly (500–600 pg/g) is present at the base of the Pinna Layer, which presumably represents the record of the bolide impact. Correlation with the iridium layer at the Global Stratotype Section and Point at El Kef, Tunisia, would, therefore, imply that these assemblages are actually Danian, provided that the iridium anomaly is in place and the ammonites and dinoflagellates are not reworked. If the iridium anomaly is in place, or even if it has migrated downward from the top of the Pinna Layer, the ammonites would have survived the impact at this site for a brief interval of time lasting from a few days to hundreds of years.

9

Ammonite faunal dynamics across bio-events during the mid- and Late Cretaceous along the Russian Pacific coast

72%

Jagt-Yazykova E. A.

Acta Palaeontologica Polonica

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2012

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tom 57

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nr 4

EN

The present paper focuses on the evolutionary dynamics of ammonites from sections along the Russian Pacific coast during the midand Late Cretaceous. Changes in ammonite diversity (i.e., disappearance [extinction or emigration], appearance [origination or immigration], and total number of species present) constitute the basis for the identification of the main bio−events. The regional diversity curve reflects all global mass extinctions, faunal turnovers, and radiations. In the case of the Pacific coastal regions, such bio−events (which are comparatively easily recognised and have been described in detail), rather than first or last appearance datums of index species, should be used for global correlation. This is because of the high degree of endemism and provinciality of Cretaceous macrofaunas from the Pacific region in general and of ammonites in particular.

10

Terminal Maastrichtian ammonites from Turkmenistan, Central Asia

72%

Machalski M. , Jagt J. W. M. , Alekseev A. S. , Jagt-Yazykova E. A.

Acta Palaeontologica Polonica

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2012

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tom 57

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nr 4

EN

A complete uppermost Maastrichtian–Danian succession in the Sumbar River section, western Kopet Dagh (southwest Turkmenistan, Central Asia), constitutes one of the few instances in the world where the fossil record of the last ammonites can be directly positioned with respect to the iridium−rich, impact−related clay layer, which defines the Cretaceous–Paleogene (K–Pg) boundary. Two ammonite taxa, Baculites cf. vertebralis and Hoploscaphites constrictus johnjagti, range up to a level directly beneath the K–Pg boundary clay in the Sumbar River section. Thus, these two forms probably survived until the very end of the Maastrichtian in the western Kopet Dagh area. The terminal Maastrichtian ammonite records from the Sumbar River area represent the southeasternmost occurrences of these essentially Boreal taxa.

11

Evolution of the Goniatitaceae and Visean-Namurian biogeography

72%

Korn D.

Acta Palaeontologica Polonica

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1997

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tom 42

|

nr 2

177-199

EN

Evolutionary lineages within the Carboniferous ammonoid superfamily Goniatitaceae can be recognized using cladistic and stratophenetic analyses, showing that both approaches lead to coinciding results. In the late Viséan and Namurian A, ammonoid provinces can be defined by the distribution of lineages within the goniatite superfamily Goniatitaceae. The first province corresponds to the Subvariscan Realm (where the superfamily became extinct near the Viséan-Namurian boundary), and the second embraces the majority of the occurrences, e.g. the south urals, central Asia, and North America (where the superfamily with different independent lieages continued up into the late Namurian A). In the Viséan, the superfamily was, in two short epochs, globally distributed with major transgressions, which probably led to migration events. The first is at the end of the late Viséan A (G. fimbriatus and G. spirifer Zones, when the genus Goniatites had a world-wide distribution with various species), and the second at the beginning of the late Viséan C (L. poststriatum Zone, when Lusitanoceras is globally distributed).

PL

Przy zastosowaniu metod analizy kladystycznej i stratofenetycznej rozpoznano linie ewolucyjne w obrębie karbońskiej nadrodziny goniatyrtów Goniatitaceae. Obie metody dały podobne rezultaty. W późnym wizenie i w namurze A prowincje goniatytowe mogą być zdefiniowane na podstawie rozmieszczenia poszczególnych linii Goniatitaceae. Pierwsza prowincja odpowiada obszarowi subwaryscyjskiemu, gdzie goniatyty tej nadrodziny wymarły w pobliżu granicy wizen-namur. Druga prowincja obejmuje resztę obszarów występowania nadrodziny, a więc np. południowy Ural, środkową Azję i Amerykę Północną, gdzie Goniatitaceae przetrwały do Namuru A. Goniatitaceae miały światowe rozprzesrzenienie podczas dwóch krótkich epok wielkich transgresji w wizenie, które ułatwiały migracje. Pierwsza z tych epok odpowiada późnemu wizenowi A, kiedy rodzaj Goniatites (Zony G. fimbriatus i G. spirifer) miał światowe rozprzestrzenienie. Druga epoka przypadła na początek późnego wizenu C, kiedy to światowe rozprzestrzenienie miał rodzaj Lustinoceras (Zona L. poststriatum).

12

The last Cretaceous ammonites in Latin America

72%

Stinnesbeck W. , Ifrim C. , Salazar C.

Acta Palaeontologica Polonica

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2012

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tom 57

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nr 4

EN

Sections yielding late Maastrichtian ammonite assemblages are rare in Latin America and precise biostratigraphic correlation with European type sections remains difficult. In all, the extinction pattern of ammonites appears to differ between sites in southern high latitudes and those in the tropics to subtropics. In austral sections of Chile, and possibly also in southern Argentina, diverse assemblages range throughout most of the substage and then show a gradual decline prior to the Cretaceous–Paleogene (K–Pg) boundary. Further north, in northeast Brazil, only two genera (Diplomoceras, Pachydiscus) range into the uppermost Maastrichtian, but disappear within the last 0.3 Ma of the Cretaceous. In tropical sections of Columbia and Mexico, the decline of ammonites started earlier and Sphenodiscus is the last ammonite known to occur in the late Maastrichtian. In all sections revised here the disappearance of ammonites was completed prior to the end of the Maastrichtian and was thus independent of the asteroid impact at, or near, the end of the Cretaceous.

13

Exploring the limits of morphospace: ontogeny and ecology of Late Visean ammonoids from the Tafilalt, Morocco

72%

Klug C. , De Baets K. , Korn D.

Acta Palaeontologica Polonica

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2016

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tom 61

|

nr 1

EN

Early late Viséan ammonoid assemblages in Morocco are composed of diverse and well-preserved specimens. The material was found in a plain in the Tafilalt (eastern Anti-Atlas). Here, we describe mass-occurrences of juvenile specimens, in which subadult and adult specimens occur in low numbers. The juveniles of some species display a conch morphology that differs fundamentally from the adult stages. Accordingly, we emend the species diagnoses of Goniatites lazarus as well as Calygirtyoceras darkaouaense, introduce the species Entogonites bucheri sp. nov., and discuss possible ecological implications of the morphologic changes throughout ontogeny. In particular, we compare the changes in conch morphology through ontogeny in the light of Pareto Optimiality according to which the morphology of organisms would fill a polygon or polyhedron in morphospace. Data points in one of the vorteces of the polyhedron indicate optimisation for the corresponding task. Although shape is not a proof of function, it appears plausible that juvenile conchs were selected rather for compactness while adult conchs were positively selected for conchs with improved hydrodynamic properties. This appears plausible because at small conch diameters, swimming movements will not suffice for effective translocation and a planktonic mode of life is likely.

14

Size-shape relationships in the Mesozoic planispiral ammonites

72%

Parent H. , Greco A. F. , Bejas M.

Acta Palaeontologica Polonica

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2010

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tom 55

|

nr 1

EN

Ammonites are of outstanding importance in dating events of the Mesozoic and in the study of mechanisms, modes and timing of evolutionary processes. These applications rely on a detailed understanding of their morphology and the modes of variation. It has been known for a long time that their shape is composed of a number of highly correlated features. A new model, called the ADA−model, is introduced for the study of shell morphology (size and shape). The new model is based on classic dimensions which are stable parameters throughout ontogeny, giving very close agreement between pre− dictions and actual observations. It was applied in the exploration of the morphospace occupied by the planispirally coiled and the regularly uncoiled Mesozoic Ammonoidea, based on two new reduced morphospaces introduced for the analysis. Results obtained expose close relationships between size and shape, and general patterns in the ammonite shell morphol− ogy and morphogenesis. (i) The relative apertural height of the whorl section relative to the diameter of the shell (H₂/D) is involved in definition of size and shape. (ii) This same dimension shows a strong tendency to be H₂/D = 0.3. (iii) There are some geometrically possible shell shapes (or morphotypes) which seem to have not been developed since they are not known in the current record. Assuming the known ranges of protoconch size and whorl number as constraints, the ADA−model strongly suggests that these morphotypes have not been developed for the too large or too small sizes the shells would have attained, well outside of the actual size range of the planispirally coiled Ammonoidea. (iv) The law of covariation is shown to be a general pattern within the planispiral ammonites which describes structured variation of the shell shape. (v) A large fraction of the non−structured variation seems originate in the lack of correlation between the rela− tive umbilical diameter and width of the whorl section.

15

Using abundance data to assess the relative role of sampling biases and evolutionary radiations in Upper Muschelkalk ammonoids

72%

McGowan A. J. , Kiessling W.

Acta Palaeontologica Polonica

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2013

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tom 58

|

nr 3

EN

The Middle Triassic ammonoid genus Ceratites diversified spectacularly within the Germanic Muschelkalk Basin during the Anisian/Ladian (244–232 Mya). Previous studies have interpreted this diversification as a sequence of rapid, endemic radiations from a few immigrant taxa. Here we investigate the possibility that geological and sampling biases, rather than ecological and evolutionary processes, are responsible for this pattern. A new specimen−based dataset of Ceratites species−richness and abundance was assembled. This dataset was combined with 1:200 000 geological maps in a geodatabase to facilitate geospatial analyses. One set of analyses compared species richness per geological map with the number of occurrences and localities per map. Per−map change in the amount of rock available to sample for fossils was also included as a variable. Of these three variables, number of occurrences is the most strongly correlated with richness. Variation in the amount of rock is not a strong determinant of species−richness. However, rarefaction of basin−wide species/abundance data demonstrates that differences in species−richness through time are not attributable to sample size differences. The average percent similarity among sites remained close to 50% throughout the Upper Muschelkalk. The rank abundance distribution (RAD) of species from the first interval of the Upper Muschelkalk is consistent with colonization of a disturbed environment, while the other two intervals have RADs consistent with more stable ecosystems. These results indicate that genuine ecological and evolutionary events are partly responsible for the observed differences in richness and abundance. Although changes in the RADs through time support changes in the ammonoid assemblage structure, the processes underlying increasing richness and change in RADs cannot be explained by increasing geographic distinctiveness or isolation among the ammonoid assemblages present at different localities.

16

The origin of ammonoid locomotion

72%

Klug C. , Korn D.

Acta Palaeontologica Polonica

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2004

|

tom 49

|

nr 2

EN

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.

17

The soft-tissue attachment scars in Late Jurassic ammonites from Central Russia

58%

Mironenko A. A.

Acta Palaeontologica Polonica

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2015

|

tom 60

|

nr 4

EN

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.

18

Extreme abundance of ammonoids in mass accumulations from the Late Devonian of the Moroccan Anti-Atlas

58%

Greif M. , Nebelsick J. H. , Klug C.

Acta Palaeontologica Polonica

|

2022

|

tom 67

|

nr 3

19

Late Famennian (Devonian) Balviinae (Ammonoidea) from the Holy Cross Mountains, Poland

58%

Woroncowa-Marcinowska T.

Acta Geologica Polonica

|

2011

|

tom Vol. 61, no. 1

35-45

EN

Five species of the Late Famennian family Balviinae korn 2002, Effenbergia lens korn, 1992, E. minutula korn, 1992, Kenseyoceras nucleus (schmidt, 1924), K. biforme (schindewolf, 1937), and Balvia globularis (schmidt, 1924), are described from the Holy Cross Mountains, Central Poland. The material comes from the "Wocklumeria Beds" of the kowala, ostrówka and Besówka sections, possibly from the Effenbergia lens - Parawocklumeria paradoxa zones and from the upper part of the Wocklumeria sphaeroides Zone - Epiwocklumeria applanata subzone of the Late Famennian.

20

New Lower Kimmeridgian ataxioceratin ammonite from the eastern Iberian Chain, Spain: Systematic, biogeographic, and biostratigraphic relevance

58%

Moliner L. , Oloriz F.

Acta Palaeontologica Polonica

|

2010

|

tom 55

|

nr 1

EN

New ammonites collected bed−by−bed from the upper part of Ataxioceras hypselocyclum Chronozone deposits in the eastern Iberian Chain are described as Geyericeras gen. nov. The new genus includes microand macroconchiate Ataxioceratinae of small size, with moderate to loose coiling and subpolyplocoid ribs, a character crucial for its identification. Key points for the comparative identification of Geyericeras gen. nov. are: (i) microconchiate Geyericerasshow morphological convergence with evolute specimens of the stratigraphically older genus Schneidia [m]; (ii) contemporary Ataxioceratinae genera such as Ardescia [m, M] and Lithacosphinctes [m, M] did not develop subpolyplocoid ribbing; (iii) smoothing of sculpture combined with short primary ribs are not realized in Geyericeras gen. nov. [M] and can be therefore used to separate the new genus from Ataxioceras[M]; and (iv) smaller shells, and weaker and less dense ribbing with no parabolic structures differentiate Geyericeras gen. nov. [m, M] from Parataxioceras[m, M], as well as the type of subpolyplocoid ribs seen among microconchiate specimens of these two genera. The new species Geyericeras aragoniense sp. nov. is the index and guide fossil for identification of a biohorizon occurring below the first occurrence of the genus Crussoliceras in the eastern Iberian Chain.