Vol 104 n. 1
Stratigraphy and fusulinids of the Moscovian Stage (Middle
Carboniferous) in the southwestern Darvaz (Pamir).
Ernst Ja. Leven
Abstract. A refined subdivision, based on fusulinids, of the Moscovian stage in southwestern Darvaz is proposed. Seven local zones, three in the Lower Moscovian substage and four in the Upper Moscovian substage were established, based on investigations of three stratigraphic sections. The zones were correlated with those of the Eastern European and Middle Asian stratigraphic schemes. One hundred and forty-three species and subspecies, which belong to 29 genera and 13 families of fusulinids, were identified in the Middle Carboniferous of Darvaz. Among them, one genus (Undatafusulina) and 16 species, i.e. Taitzehoella compacta, Ovatella panjensis, Aljutovella darvasica, Undatafusulina asiatica, Citronites panjensis, C. reticulatus, Beedeina darvasica, B. dutkevichi, Putrella admiranda, Hemifusulina orientalis, Fusulinella (Moellerites) subundulata, F. (M.) jucunda, F. (M.) orientalis, F.(Fusulinella)
crassitectoria, F. (F.) bogushi, and F. (F.) pamirensis are new.
THE GEN. COMELICANIA FRECH, 1901 (BRACHIOPODA) FROM THE SOUTHERN ALPS:MORPHOLOGY AND CLASSIFICATION
Renato POSENATO
Abstract. Analysis of the internal characters, especially the cardinalia and brachidium, of the brachiopod Comelicania Frech from the Southern Alps, confirmed the attribution of this genus to the Superfam. Athyridoidea Davidson and provided a more complete taxonomic description of the Fam. Comelicaniidae Merla. This family includes two genera which differ in the morphology of their cardinalia, i.e. Gruntallina Waterhouse & Gupta, type-species Gruntallina triangularis (Grunt) from the lower Dorashamian of Transcaucasia and Comelicania, type-species Comelicania megalotis (Stache) from the uppermost Bellerophon Fm. of the Southern Alps.
The study of a collection composed of more than a hundred specimens highlighted a broad variability of the morphological characters and a pattern of ontogenetic development which demonstrates that classification at the species level is possible only when using mature specimens. Taxonomic revision at the specific level reduced the eleven species of Comelicania from the Southern Alps, described by previous authors, to: C. megalotis (Stache) and C. haueri (Stache). In addition a new species, C. merlai, which characterises the upper Comelicania beds, is proposed.
JURASSIC PALAEOGEOGRAPHY OF THE TRANSDANUBIAN CENTRAL RANGE (HUNGARY)
Attila VÖRÖS & András GALÁCZ
Abstract. The Transdanubian Central Range (TCR) is a flattened range of hills in northern Transdanubia (Hungary), formed mainly by Mesozoic carbonate rocks showing strong facies similarities with the Southern Alps and the Austroalpine domain. The Jurassic system is divided into several formations of predominantly pelagic limestones. Ammonoids are frequent and were collected bed-by-bed in numerous sections, providing an excellent biostratigraphic resolution. The thickness of the Jurassic system is usually small but changes along the strike of the TCR. It reaches a maximum thickness of 500 m in the western part; is very variable (10-400 m) in the central segment (Bakony Mts.) and rather low (less than 100 m) in the east (Gerecse). In the Bakony segment, the thickness variation reflects the strongly dissected topography of the Jurassic sea-floor. Synsedimentary tectonics is dominated by normal faults; tilted blocks and listric faults may be inferred only in the east.
Five main steps were identified in the palaeogeographic evolution:
1) Late Hettangian: carbonate oolitic shoals prevail, except for a few sites where non-deposition or neritic sediments occur.
2) Sinemurian and Pliensbachian: tectonic disintegration resulted in an intricate pattern of submarine horsts and intervening basins, with condensed sedimentation or non-deposition on the horsts and thicker, continuous sedimentary sequences in the basins. The submarine topographic highs are surrounded by aprons of redeposited material (scarp breccias, brachiopod coquinas, crinoidal calcarenites, spiculitic cherty limestones), while pure or argillaceous limestones (Rosso Ammonitico) prevail in the distal areas.
3) Early Toarcian: the Tethys-wide anoxic event is superimposed on the previous submarine bottom topography; the resulting black shales and sedimentary Mn-ores are concentrated on the western sides of some horsts.
4) Dogger to Early Malm: radiolarites with heterochronous lower and upper boundaries (Aalenian to Kimmeridgian) prevail, except for the top of some submarine topographic highs. The absence of uppermost Bathonian to Lower Oxfordian carbonates suggests that the whole TCR sunk below the CCD in those times.
5) Latest Jurassic: the uniform deposition of Rosso Ammonitico and Biancone in the Late Kimmeridgian and Tithonian is interrupted only in the Early Tithonian by local intercalations of scarp breccias and coarse biodetrital limestones. This is interpreted as the last manifestation of synsedimentary tectonic movements along the faults bordering the submarine horsts.
Based on palaeogeographic similarities and analogies in Jurassic times, the TCR is visualized as the northern foreground of the Trento platform/plateau (lying north of the later Insubric lineament), where the block-tectonic disintegration and differential subsidence started earlier and resulted in a bottom morphology more dissected than in the South Alpine part of this west Tethyan passive margin.
New data on Middle to Late Miocene calcareous plankton biostratigraphy in the Mediterranean area
Luca Maria Foresi, Silvia Iaccarino, Roberto Mazzei & Gianfranco Salvatorini
Abstract
. Planktonic foraminifera from one Atlantic Ocean (Site 397) and five Mediterranean sequences of middle to late Miocene age were investigated. The aim of the research was to refine the biostratigraphy of the Serravallian to early Tortonian interval and, since the recent literature provides no general consensus, to check the range of Neogloboquadrina acostaensis (Blow) and Paragloborotalia siakensis (Le Roy).Examination of planktonic foraminifera identified a succession of events which is, in part, new in the Mediterranean area, and documented an overlap in the distribution of N. acostaensis and P.lia siakensis.
Based on the new data, the zonal scheme for the Serravallian to early Tortonian interval proposed by Iaccarino and Salvatorini (1982) and Iaccarino (1985) was emended. In particular, it was ascertained that the first occurrence (FO) of N. acostaensis falls in the upper part of the Serravallian, well before the last occurrence (LO) of P.lia siakensis .
The new zonation was calibrated with the calcareous nannofossil zonation and the geomagnetic polarity time scale. In light of these new data, the events closest to the base of the Rio Castellania-Rio Mazzapiedi-Tortonian type-section are interpreted to be the LO of P.lia siakensis, the first common occurrence (FCO) of N. acostaensis, and the FO of Discoaster hamatus.. Therefore, the use of these events in selecting the GSSP of the Serravalian/Tortonian boundary is recommended.
Revision and re-documentation of M. Airoldi’s species of Mesophyllum from the Tertiary Piedmont Basin (NW Italy)
Daniela Basso°, Patrizia Fravega°°, Michele Piazza ° & Grazia Vannucci°°
Abstract. Airoldi (1930, 1932) described twenty-three fossil Corallinales (Rhodophyta) from the Oligocene of the Tertiary Piedmont Basin (NW Italy), including thirteen new species. In this paper Mesophyllum fructiferum Airoldi 1932 and Mesophyllum obsitum Airoldi 1932 are re-documented and re-described. The presence of cell fusions, multiporate conceptacles and a ventral core of cell filaments passing from coaxial to non-coaxial confirm that both species belong to the genus Mesophyllum.
SHORT NOTES
A PHYTOSAUR SKULL FROM THE NORIAN (LATE TRIASSIC) OF LOMBARDY (NORTHERN ITALY)
Silvio Renesto & Anna Paganoni
Abstract. An isolated phytosaur skull found in the Calcare di Zorzino (Norian, Late Triassic), near the locality of Endenna (Bergamo Prealps, Lombardy, Northern Italy), is described. The skull lacks the mandible and is severely compressed and distorted in its posterior portion. Nevertheless it is possible to ascribe it to the genus Mystriosuchus, likely to Mystriosuchus planirostris, already known on the basis of excellent specimens from the Stubensandstein Formation in Germany. This finding represents one of the rare large reptile specimens found in the Norian fossil-bearing localities of Lombardy, along with a new phytosaur yet to be prepared and a nearly two meters long specimen of the placodont Psephoderma alpinum.
Middle Pliocene cetaceans from Monte Voltraio (Tuscany, Italy). Biostratigraphical, paleoecological and paleoclimatic observations.
Giovanni Bianucci, Giovanni Sarti , Rita Catanzariti, Ubaldo Santini
Abstract.
The historic collection of fossil odontocetes (Cetacea) from Monte Voltraio, near Volterra (Tuscany, Italy) has been examined and lithostratigraphical and biostratigraphical investigations on the find locality have been carried out. The Monte Voltraio outcrop is referred to the Middle Pliocene, in particular to Globorotalia aemiliana and Discoaster tamalis zones. The odontocete remains are assigned to the families Kogiidae (Kogia pusilla) and Delphinidae (Globicephala? etruriae and two indeterminate specimens which might belong to Hemisyntrachelus and Stenella giulii). The Middle Pliocene cetacean fauna from the Mediterranean basin (Monte Voltraio and Rio Stramonte associations) includes extinct taxa or extant taxa no longer represented in this basin. The disappearance of these taxa may be linked with the Pliocene and/or Quaternary climatic deteriorations (e.g. the climatic crisis at about 2.6-2.4 MA) .
Tube morphology and structure of the bathyal Mediterranean serpulid Hyalopomatus variorugosus
Ben-Eliahu & Fiege, 1996 (Annelida, Polychaeta)
Rossana Sanfilippo
Abstract. The species studied differs from the other Hyalopomatus species by having a peculiar rugose sculptured outer tube surface. This character is markedly variable; it can be more or less developed and may also vary along the same tube. Observed by SEM, this rugosity proves to consist of irregular flaps, roughly following the growth lines.
SEM observations on transverse fractures show a homogeneous composition of the tube wall, consisting of calcium carbonate crystals. These crystals show a prismatic habitus and are arranged in a homogeneous granular microcrystalline structure.
New records of H. variorugosus are from deep water stations in the Western Mediterranean and from Pleistocene bathyal deposits of Southern Italy.
The discussion covers aspects of tube characters of use for taxonomy.