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TREPOSTOME AND CRYPTOSTOME BRYOZOANS FROM THE KONĔPRUSY LIMESTONE (LOWER DEVONIAN, PRAGIAN) OF ZLATÝ KÙÒ (CZECH REPUBLIC)
ANDREJ ERNST
The present paper presents descriptions of 10 bryozoan species from material deposited at the Geological Centrum Göttingen, Germany. The studied material comes from the Lower Devonian rocks (Konĕprusy Limestone, Pragian), exposed in a quarry near Zlatý Kùò in Central Bohemia. Described bryozoans comprise 8 trepostome and 2 cryptostome (rhabdomesine) species. One genus and species is new: the cryptostome (rhabdomesine) Paracuneatopora striata gen. n., n. sp., and 7 species are new: trepostomes Leioclema elegans n. sp., Atactotoechus divulgatus n. sp., Loxophragma fistulosum n. sp., Leptotrypella punctata n. sp., Microcampylus obscurus n. sp., Dyscritella bohemica n. sp., and the rhabdomesine Orthopora tenuis n. sp. Furthermore, two trepostomes Monotrypa bohemica Prantl, 1933 and Anomalotoechus cf. typicus Duncan, 1939 were identified in this material. The described fauna displays palaeozoogeographic relations to the Lower Devonian (Pragian) of Morocco and the Middle Devonian of Michigan (USA).
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GLOMOMIDIELLA N. GEN. (FORAMINIFERA, MILIOLATA, NEODISCIDAE): A NEW GENUS FROM THE LATE GUADALUPIAN-LOPINGIAN OF HYDRA ISLAND (GREECE)
DANIEL VACHARD, ROBERTO RETTORI, LUCIA ANGIOLINI & ALESSIO CHECCONI
A new genus of Foraminifera (Miliolata, Cornuspiroidea, Neodiscidae) is erected from the late Guadalupian (Capitanian = Midian) to Lopingian sedimentary succession of the island of Hydra (Greece). It represents an important phylogenetic form, probably at the origin of several genera (or subfamilies of the authors) that became relatively widespread during the Lopingian (Late Permian). Glomomidiella n. gen. is characterized by an entirely glomospiral coiling and rudimentary pseudoseptation.
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A NEW SPECIES OF THE GENUS COLOBODUS AGASSIZ, 1844 (OSTEICHTHYES, ACTINOPTERYGII) FROM THE PELSONIAN (ANISIAN, MIDDLE TRIASSIC)
OF GUIZHOU, SOUTH CHINA
SUN ZUOYU, ANDREA TINTORI, CRISTINA LOMBARDO, JIANG DAYONG,
HAO WEICHENG, SUN YUANLIN, WU FEIXIANG & MARCO RUSCONI
Eight almost complete medium-large sized (about 33 cm in s.l.) fossil fishes, belonging to the family Colobodontidae, are described from the Pelsonian (Anisian, Middle Triassic) of South China. Their cranial and postcranial features fit those of the genus Colobodus Agassiz, 1844 from the western Tethys. However, they are older than the previously known Colobodus species and, furthermore, they come far from the western Tethys, where most colobodontids have been found so far. The significance of our new findings, beyond the erection of a new species, lies in the fact that they are the first definite record of Colobodus outside the western Tethyan faunal province, and represent the oldest unequivocal colobodontids worldwide, as well as suggest that they could have originated in the East rather than the western Tethys, as previously thought.
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SELECTED AMMONOID FAUNA FROM PRATI DI STUORES/STUORES WIESEN AND RELATED SECTIONS ACROSS THE LADINIAN-CARNIAN BOUNDARY
(SOUTHERN ALPS, ITALY)
PAOLO MIETTO, STEFANO MANFRIN, NEREO PRETO & PIERO GIANOLLA
The ammonoid fauna of the Prati di Stuores/Stuores Wiesen section (Dolomites, north-eastern Italy) was studied in detail. This section was proposed as stratotype for the Carnian GSSP, with the first appearance of Daxatina cf. canadensis as primary marker, based on preliminary data. The validity of this proposal is confirmed by the present study, which integrates collections from the Prati di Stuores/Stuores Wiesen section and from others, particularly Bec de Roces (Passo Campolongo) and Antersass (Badia Valley). Ammonoids collected in these localities belong to three biostratigraphic units: regoledanus, canadensis and aon subzones. These subzones constitute, in the Southern Alps, the Ladinian/Carnian boundary interval. Regoledanus Subzone: the north American species Zestoceras enode is most probably documented in this biostratigraphic interval. Canadensis Subzone: the base is marked by the first appearance of Daxatina canadensis, and at least, another north American species, Daxatina laubei, seems to be present. Two species of Zestoceras were found: Z. barwicki e Z. lorigae sp.n. Two species of Trachyceras, distinct from T. aon, are represented in the canadensis Subzone: T. muensteri and T. bipunctatum. These species predate the first appearance of Trachyceras, justifying the canadensis Subzone to be included in the Carnian also on the basis of nomenclatural stability. Other significant taxa of this subzone are Rossiceras? armatum and Sirenotrachyceras thusneldae. Aon Subzone: the ammonoid fauna of this subzone is extensively treated in existing literature and thus not further discussed. Taxonomical notes and stratigraphic consequences: the new subfamily Anolcitinae (family Trachyceratidae) is erected. At present, Frankites regoledanus, F. apertus and F. sp. A have been recognized in the Southern Alps. The lectotype of Ammonites (Trachyceras ?) Regoledanus was defined. The latter species is exclusive of the regoledanus Subzone, whereas the distribution of the two other species encompasses the defined GSSP. The shell morphology of F. apertus and the north American species F. sutherlandi is identical. The suture line is also comparable, hence the two species are considered synonyms. This synonymy is relevant for long-distance correlations. The lectotypes of Trachyceras ruturanum and T. laricum were also defined.
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The Triassic/Jurassic boundary in a peritidal carbonate platform of the Pelagonian Domain: the Mount Messapion section (Chalkida, Greece)
Roberta Romano, Daniele Masetti, Nicolaos Carras,
Filippo Barattolo & Guido Roghi
In the Mount Messapion area (Chalkida, Greece) a continuous and expanded section of Triassic/Jurassic (T/J) limestone is exposed. This section consists of a 710 m thick pile of shallowing-upward peritidal cycles; the persistence of the facies and the lack of paleoenvironmental changes across the T/J boundary allowed studying the distribution of shallow water microfossils. The T/J boundary is placed in the upper part of the section defined by correspondence with (i) the last occurrence of Triasina hantkeni, (ii) the abrupt disappearance of megalodontid faunas and (iii) the presence of Early Jurassic microfossil assemblages. This paleontological reorganization happens suddenly, it is not controlled by any facies change, and surprisingly, it seems to produce no evident modification in the vertical stacking pattern of the cycles. A detailed facies analysis, performed along a 290 m thick stratigraphic interval (60 m above the T/J boundary and 230 m below), allowed the recognition of peritidal cycles: five different elementary cyclothemes are described and their distribution along the section is given. This integrated stratigraphic study attempts to highlight the relationship between the changes of carbonate producers and sea level fluctuations across the T/J boundary.
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THE HETTANGIAN SHALLOW WATER CARBONATES AFTER THE TRIASSIC/JURASSIC BIOCALCIFICATION CRISIS: THE ALBENZA FORMATION IN THE
WESTERN SOUTHERN ALPS
FLAVIO JADOUL & MARIA TERESA GALLI
This study investigates the stratigraphic and sedimentologic setting of an early Hettangian carbonate platform in the Lombardy Basin, taking into account the Triassic-Jurassic (Tr-J) post-crisis evolution and the geodynamic setting related to the beginning of the Early Jurassic rifting. The historical name of this platform ("Conchodon Dolomite"), not adequate for the absence of Conchodon and for the mainly calcareous lithology, has been replaced with Albenza Formation. The depositional model of this carbonate platform unit is coherent with a leeward Great Bahama Bank-type environment, without any reefs facing deep water environments. The unusual abundance of ooids and marine cements, in the basal progradational ramp-type margins, reflects temporal variation in the saturation state of seawater after the Tr-J crisis, possibly due to marine calcified cyanobacteria blossom. The absence of biotically induced margins related to the (biocalcification) Tr-J crisis and the concomitant tectonic fragmentation, with different subsidence rates of the Tethyan passive margin, conditioned the drowning and the eastward retrogradation of the Albenza platform.
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ages of the onset of marly sedimentation and of the black shales in the Tuscan Basin (Northern Apennines, Italy)
Nicola Perilli, Viviana Reale & Luiz carlos Veiga de Oliveira
In this paper is for the first time dated the inception of the Lower Jurassic marly sedimentation and the lower Toarcian black shales in the Tuscan Nappe, based on semiquantitative analysis of the calcareous nannofossils recovered from the Calcare selcifero di Limano/Calcari e marne a Posidonia transition and the lower part of this latter unit. The boundary between these formations lies within the nannofossil NJT5 Lotharingius hauffii Zone (uppermost Pliensbachian to lower Toarcian), the lower portion of the Calcari e marne a Posidonia ranges from the nannofossil NJT5 Lotharingius hauffii Zone to the NJT7 Discorhabus striatus Zone (middle Toarcian) and the organic-rich interval lies in the nannofossil NJT6 Carinolithus superbus Zone (lower Toarcian). Consequently, the changes from carbonate-dominated to marly-dominated sedimentation (NJT5 Zone) and the black shales accumulation (NJT6 Zone) in the Tuscan and Umbria-Marche basins are two coeval sedimentary events.
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CALLOVIAN RADIOLARIANS FROM THE LOWERMOST CALCARE SELCIFERO DI FONZASO AT PONTE SERRA (TRENTO PLATEAU, SOUTHERN ALPS, ITALY)
PAOLA BECCARO, MARC-OLIVIER DISERENS, SPELA GORICAN & LUCA MARTIRE
This paper deals with radiolarian biostratigraphy of the Calcare Selcifero di Fonzaso at the type-section of Ponte Serra (Southern Alps, Italy). The Ponte Serra section is located on the easternmost part of the Trento Plateau and represents an early-drowned sector that marks the transition to the Belluno Trough.The Calcare Selcifero di Fonzaso consists of pelagic siliceous limestones of Middle to Late Jurassic age for a total thickness of about 70 m. A 24 metres thick package of resedimented limestone is interstratified. This research is focused on the lowermost part, 9 metres thick, that mainly consists of red and green siliceous micrites with interbedded clay beds and abundant chert lenses and nodules. The studied interval lies between the lower member of the Rosso Ammonitico Veronese Formation below and the resedimented limestone above. The recovered radiolarian assemblages indicate a Callovian age for the base of the Calcare Selcifero di Fonzaso. Correlation with other sections of the Trento Plateau reveals a significant diachronism in siliceous sedimentation that we relate to highly irregular sea-bottom paleotopography. The base of siliceous deposits can be even older (Bathonian) on the eastern margin of the Trento Plateau, but younger (Oxfordian) on its western margin. The Callovian succession of the Belluno Trough consists of radiolarian-bearing micrite alternating with oolitic limestone. The oolitic sands that filled in the Belluno Trough during the Middle Jurassic prograded over the eastern margin of the Trento Plateau in the early Oxfordian.
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COUPLING AMPULLINID GASTROPODS: SEXUAL BEHAVIOUR FROZEN IN PALAEOGENE DEPOSITS OF NORTHERN ITALY
IGINIO DIENI
Couples of the ampullinid gastropods Globularia (Eocernina) vulcani (Brogniart, 1823), Amaurellina (Crommium) angustata (Grateloup, 1827) and Amaurellina (Pachycrommium) cf. suessoniensis (d'Orbigny, 1850), composed of dimorphed shells tightly conjoined at the apertures, from the Palaeogene (Eocene and Oligocene) marine successions of northern Italy, are interpreted as buried while mating, specimens being "frozen" while suddenly covered by a mass of sediment. Violent depositional events were responsible for their rapid burial, primarily by volcanoclastics, the formation of which had also involved acidification. The consequent poisoning of sea water and/or overwarming beyond the range in which the gastropods could survive, induced mass mortality. A similar set of conditional circumstances is also discussed for differently sized coupled specimens of Ampullinopsis crassatina (Lamarck, 1804), preserved with their shells slightly apart but with their apertures almost in contact. With reference to the catastrophic eruption of Vesuvius in A.D. 79, when Pompei was buried under tephra, it is thought that volcanic activity caused the death and burial of all these pairing gastropods in a "Pompeian" way.
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REVISION AND RE-DOCUMENTATION OF M. AIROLDI'S SPECIES OF LITHOPHYLLUM FROM THE TERTIARY PIEDMONT BASIN
GRAZIA VANNUCCI, FRANCESCA QUARANTA & DANIELA BASSO
The species originally attributed by Airoldi (1932) to the genus Lithophyllum (L. perrandoi, L. ligusticum, L. personatum and L. desitum) are here re-examined on the basis of the original material, original descriptions and illustrations. L. perrandoi and L. ligusticum are considered to be conspecific and questionably retained in the genus Lithophyllum. We give priority to the name ?L. perrandoi Airoldi to honour the priest Don Perrando, who collected most of the fossils conserved in the Dip.Te.Ris of Genova. L. personatum and L. desitum do not belong to the genus Lithophyllum as presently circumscribed. L. personatum Airoldi is a female/carposporangial plant of a mastophoroid species resembling Spongites fruticulosus Kützing, and therefore we retain a dubitative identification with the new combination ?Spongites personatus (Airoldi). L. desitum is here placed in the genus Mesophyllum under the new combination Mesophyllum desitum (Airoldi). On the basis of its vegetative and reproductive features, M. desitum comb. nov. is here considered conspecific with Mesophyllum obsitum Airoldi.
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