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A new etching trace from the Savignone Conglomerate (Oligocene), NW Italy, probably produced by limpet gastropods

100%

Uchman A. , Rattazzi B.

tom Vol. 68, no. 4

651--662

A new ichnogenus and ichnospecies (Solealites ovalis) of etching trace is preserved on the surfaces of clasts from the Savignone Conglomerate (Oligocene) in the Palaeogene Piemonte Basin in NW Italy. It is a shallow, oval depression with a central elevation, which was produced probably by limpet gastropods and served as their home scar, but other gastropods or even sea anemones are not excluded as the trace makers. The conglomerate is interpreted as a deposit of a fan delta, whose clasts have been bioeroded in an intertidal and shallow subtidal shore zone and redeposited to the deeper sea.

A new heterobranch gastropod, Chelidonura radwanskii sp. nov., from the middle Miocene of the Korytnica Basin (Holy Cross Mountains, Poland)

100%

Bałuk W.

tom Vol. 68, no. 4

499--502

A new species of heterobranch gastropods, the hammerhead Chelidonura radwanskii sp. nov., found in the socalled Pleurotoma-clays of middle Miocene (Langhian) age in the environs of Korytnica, southern Holy Cross Mountains, Poland, is described. It is the first fossil representative of Chelidonura A. Adams, 1850. This tiny gastropod is named in honour of the late Professor Andrzej Radwański.

Fauna osadów interglacjalnych z Koczarek koło Mrągowa

80%

Skompski S.

tom Vol. 50, nr 7

615--619

Analiza paleontologiczna 46 próbek z otworu wiertniczego w Koczarkach wykazała obecność różnorodnych szczątków zwierząt: mięczaków, małżoraczków, ryb i owadów. Na tej podstawie określono warunki paleoekologiczne i paleoklimatyczne w jakich powstawały osady z fauną oraz ich stratygrafię. Znalezione tu charakterystyczne gatunki mięczaków: Corbicula fluminalis i Lithoglyphus jahni oraz małżoraczka Scottia browniana pozwalają określić wiek osadów z fauną na interglacjał mazowiecki.

The late Silurian-Middle Devonian long-term eustatic cycle as a possible control on the global generic diversity dynamics of bivalves and gastropods

80%

Ruban D. A.

tom Vol. 19, No. 3

193--200

A long-term eustatic cycle (fall and subsequent rise of the global sea level) embraced the late Silurian-Middle Devonian time interval. Potentially, these sea-level changes could drive global biodiversity. The stratigraphic ranges of 204 bivalve genera and 279 gastropod genera included into the famous Sepkoski database allow reconstructing changes in the total diversity and the number of originations and extinctions of these important groups of marine benthic macro- -invertebrates during this interval. None of the recorded parameters coincided with the long-term global sea-level cycle. It cannot be not excluded, however, that the global sea-level changes did not affect the regions favourable for bivalve and gastropod radiation because of regional tectonic mechanisms; neither can it be excluded that the eustatic control persisted together with many other extrinsic and intrinsic controls. Interestingly, the generic diversity of gastropods increased together with a cooling trend, and vice versa. Additionally, the Ludlow, Eifelian, and Givetian biotic crises affected, probably, both fossil groups under study. There was also a coincidence of the relatively high bivalve generic diversity, initial radiation of gastropods and the entire biota, and the diversification of brachiopods with the Early Devonian global sea-level lowstand, and this may be interpreted as evidence of a certain eustatic control on the marine biodiversity.

Septacja w muszlach ślimaków frańskich z Gór Świętokrzyskich

80%

Krawczyński W.

tom Vol. 57, nr 1

39-39

Amongst several known Paleozoic gastropod species having transverse septa in the apical parts of shells, three species (Straparollus aff. circularis, Orecopia kadzielniae and Donaldiella karczewskii) have been found in the Frasnian limestones of Grabina and Bolechowice-Panek in the Holy Cross Mountains (Central Poland). Septation in gastropod shells is a rare phenomenon and is an adaptive feature. Septa occur either in the thick-shelled gastropods living in high-energetic (reef) environments, preventing against negative effects of destruction of the apical parts of shells, or in the thin-shelled gastropods living on muddy substrate, lowering the inner volume of a habitable part of shell and increasing outer surface of gastropod body.