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1

Shape Variation in Spiroplectammina spectabilis (Grzybowski)

100%

Kaminski M. A.

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nr 1-2

EN

The morphology and intraspecific variation of Spiroplectammina spectabilis (Grzybowski) is investigated based upon topotype material. Linear measurements and eigenshape analyses of species of Spiroplectammina described from California show them to be conspecific with S. spectabilis. Two ecophenotypic forms are distinguished: S. spectabilis forma trinitatensis — a robust Eocene variety, and S. spectabilis forma perplexa, a minute, compressed form.

PL

Na podstawie materiału topotypowego badano morfologię i zmienność wewnątrzgatunkową Spiroplectammina spectabilis (Grzybowski), (Foraminiferida, Textulariina). Analiza „eigenshape” pozwala stwierdzić, że największa zmienność istnieje w proporcjach spirali początkowej i że zmienność wewnątrz zespołów jest większa niż pomiędzy zespołami. Porównanie pomiarów S. spectabilis sugeruje, że gatunek ten stanowi zbiór form pośrednich, aczkolwiek można wyróżniać formy końcowe. Testy statystyczne przeprowadzonych pomiarów wykazują znaczną nierównomierność parametrów pomiędzy próbkami pobranymi z różnych rejonów. Znaczące różnice w grubości skorupki pozwalają na wyróżnienie dwóch form w obrębie badanego gatunku: S. spectabilis forma perplexa i S. spectabilis forma trinitatensis. Nazwa S. spectabilis forma perplexa może być stosowana do oznaczania drobnych i spłaszczonych form, zaś S. spectabilis forma trinitatensis dla form większych i bardziej wypukłych od typowych okazów S. spectabilis.

2

Modern agglutinated Foraminifera from the Hovgård Ridge, Fram Strait, west of Spitsbergen: evidence for a deep bottom current

63%

Kaminski M. A. , Niessen F.

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tom Vol. 85, No. 1

309--320

EN

Deep-water agglutinated foraminifera on the crest of the Hovgård Ridge, west of Spitsbergen, consist mostly of large tubular astrorhizids. At a boxcore station collected from the crest of Hovgård Ridge at a water depth of 1169 m, the sediment surface was covered with patches of large (1 mm diameter) tubular forms, belonging mostly to the species Astrorhiza crassatina Brady, with smaller numbers of Saccorhiza, Hyperammina, and Psammosiphonella. Non-tubular species consisted mainly of opportunistic forms, such as Psammosphaera and Reophax. The presence of large suspension-feeding tubular genera as well as opportunistic forms point to the presence of deep currents at this locality that are strong enough to disturb the benthic fauna. This is confirmed by data obtained from sediment echosounding, which exhibit lateral variation in relative sedimentation rates within the Pleistocene sedimentary drape covering the ridge, indicative of winnowing in a south-easterly direction.

3

A new species of primitive Reticulophragmium (Foraminifera) from the Paleocene Vidono Formation of northeastern Venezuela

63%

Kaminski M. A. , Crespo de Cabrera S.

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tom Vol. 69, No. 3-4

189-193

EN

The new species Reticulophragmium vidonioensis Kaminski & Crespo de Cabrera is newly described from the subsurface Vidono Formation of northeastern Venezuela. The foraminiferal assemblage is dated as Zone P3 (mid Paleocene), and represents an outer neritic-upper bathyal biofacies. Reticulophragmium vidonioensis n.sp. displays very primitive morphological features, and illustrates the close evolutionary relationship between the earliest Paleocene alveolar genus Reticulophragmium and the non-alveolar genus Haplophragmoides.

PL

Z osadów środkowego paleocenu (zona P3) formacji Vidono w północno-wschodniej Wenezueli opisano nowy gatunek Reticulophragmium vidonioensis Kaminski & Crespo de Cabrera, należący do grupy otwornic aglutynujących. Zespół otwornic z nowo opisanym taksonem reprezentuje biofacje z pogranicza strefy nerytycznej i górnego batiału. Gatunek Reticulophragmium vidonioensis n.sp. charakteryzują cechy stawiające go jako forme pośrednią pomiędzy rodzajem Reticulophragmium o alweolarnej strukturze i rodzajem Haplophragmoides nie wykazującym w budowie wewnętrznej skorupki struktury alweolarnej.

4

Plectoeratidus subarcticus, n.gen., n.sp., a new agglutinated foraminifer from the Upper Cretaceous of the western Barents Sea

51%

Kaminski M. A. , Setoyama E. , Tyszka J.

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tom Vol. 79, No 2

141-146

EN

We describe the new foraminiferal genus and species Plectoeratidus subarcticus n.gen. n.sp., from the Upper Cretaceous deep-water deposits of the Kviting and Kveite formations in the western Barents Sea. The genus is characterised by its planispiral-biserial-uniserial chamber arrangement, terminal aperture and lateral compre- ssion. The biometric analysis of test ontogenesis has been applied to document its dimorphism attributed to megalospheric and microspheric generations. This taxon may represent an evolutionary transition between the Cretaceous genera Spiroplectammina or Bolivinopsis and the Cenozoic genus Eratidus. The taxon appears to be endemic to the flysch-type agglutinated foraminiferal assemblages in the Norwegian Sea area.

5

The phanerozoic diversity of agglutinated foraminifera: Origination and extinction rates

51%

Kaminski M. A. , Setoyama E. , Cetean C. G.

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nr 3

529-539

EN

New diversity curves for agglutinated foraminiferal genera are presented based on the stratigraphic ranges of 764 genera distributed over the 91 Phanerozoic chronostratigraphic subdivisions given in the ICS timescale. The data set for this analysis is based on the stratigraphic ranges of agglutinated genera published in Foraminiferal Genera and their Classification, 218 of which have been modified based upon subsequently published studies and new observations. Additionally, a total of 136 genera have been newly described or reinstated subsequent to the publication of Foraminiferal Genera and their Classification. The revision of stratigraphic ranges is part of the effort by the Grzybowski Foundation’s International Working Group on Foraminiferal Classification to compile a new Catalogue of Agglutinated Foraminiferal Genera. The mean standing diversity of agglutinated foraminiferal genera was compiled by counting the number of boundary crossers rather than the number of genera in each stage. This diversity curve displays a general upward trend throughout the Phanerozoic, punctuated by peaks and troughs of variable magnitude. The curve shows a period of initial radiation from the Early Cambrian to the Early Silurian, followed by a plateau to the Late Permian. The Permian/Triassic and the Triassic/Jurassic boundaries are characterised by small dips in the diversity record. The Jurassic begins with an exponential rise in mean standing diversity that continues to the Cenomanian. The Cenomanian to Holocene record of mean standing diversity is characterised by four peaks and troughs that are roughly in line with the cycles of global climate, with reductions in diversity in the end−Cenomanian, end−Cretaceous, and end−Miocene. Excluding modern values, the Phanerozoic maximum in the number of genera with a fossil record is observed in the Cenomanian, whereas the maximum Phanerozoic mean standing diversity is observed in the Langhian stage of the Miocene. The highest per−capita origination rates are observed in the Hettangian, Dapingian, Pleistocene, and Sheinwoodian (mid−Silurian). Linear regression analysis of the origination rates reveals a decrease towards the Holocene, in agreement with findings of Raup and Sepkoski. The highest per−capita extinction rates are observed in the Messinian, late Silurian (Gorstian), Hirnantian (latest Ordovician), and Maastrichtian. The background extinction rate shows an increasing trend towards the Recent, which is in disagreement with the findings of Raup and Sepkoski. We attribute this apparent discrepancy to the Late Cretaceous to Palaeogene extinctions of shallower−water larger agglutinates and the pull of the end−Miocene extinction event.

6

Seasonal variations, environmental parameters, and standing crop assessment of benthic foraminifera in eastern Bahrain, Arabian Gulf

38%

Arslan M. , Kaminski M. A. , Tawabini B. S. , Ilyas M. , Babalola L. O. , Frontalini F.

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2016

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tom Vol. 60, No. 1

26--37

EN

Living benthic foraminifera in a relatively unpolluted site offshore Bahrain in the Arabian Gulf, were studied to determine the seasonal variability of their populations, as well as environmental parameters that may affect their distribution. The maximum foraminiferal density was observed during winter with the assemblages primarily dominated by rotaliids and secondarily by miliolids. The high population is attributed to an increased number of juveniles. A relationship between sediment grain size and the foraminiferal density reveals that juveniles were most abundant on coarse-grained sandy substrate and less abundant on fine-grained substrates. In spring, the foraminiferal density decreased, and the lowest values were observed during summer. The population increased again in autumn with highest juvenile/adult ratios. Moreover, results of relative abundance and species consistency show that Ammonia and Glabratellina are consistent from the shallowest to the deepest station, whereas miliolids occurred only at deeper stations. The numbers of peneroplidae and Elphidium also increased along the depth transect. Environmental characterization reveals that although the site is subject to eutrophication caused by nitrates and sulfates, pollution caused by hydrocarbons and heavy metals is not significant. The assessment of 63 heavy metals showed that none of the metals had concentrations that exceed internationally accepted norms [the devised level of Effect Range-Low], but with high concentration of strontium. The lack of a significant environmental effect of heavy metals is confirmed by the Foraminiferal Abnormality Index of <2%. Likewise, no hydrocarbon contamination was detected in the water or sediment samples. We conclude that the site in Bahrain is not yet adversely affected by human development, and therefore can provide baseline information for future comparison and assessment of foraminiferal assemblages in contaminated zones of the Arabian Gulf.