BABA SENOWBARI-DARYAN, MICHAELA BERNECKER , LEOPOLD KRYSTYN & MILOS SIBLIK

Abstract. Carnian reef biota and brachiopods of the Misfah Formation (Hawasina complex) from a locality near the town of Al Aqil in Oman are described. A new brachiopod species, Oxycolpella arabica n. sp. is described. The composition of the Carnian reef biota in Oman is similar to those known from the Alpine-Mediterranean region. However, differences exist in the microfauna of reef dwellers, e.g. foraminifers. New stratigraphic data based on reef organisms and conodonts are presented.

Emanuela Mattioli and Elisabetta Erba

Abstract. This paper is a synthesis of calcareous nannofossil biostratigraphy for the Lower and Middle Jurassic of the Mediterranean Province based on several sections from Northern and Central Italy. Nannofossil events were calibrated with ammonite biostratigraphy and, when necessary, ammonite-controlled sections in South East France were incorporated. Data derive from previously published biostratigraphies and unpublished data of the authors.

The large data-set allowed estimates of reliability and reproducibility of single events. As a result, in the Hettangian-Bathonian interval we propose 47 main events based on diagenesis-resistant and common taxa, 17 events based on rare but ubiquitous taxa and 12 potential events requiring further investigations due to taxonomic problems and sporadic occurrence. A biostratigraphic scheme, consisting of 11 zones and 15 subzones, is proposed for the Tethyan Lower and Middle Jurassic.

The proposed biostratigraphy is compared to recent schemes compiled for Portugal, Morocco, Switzerland and the Boreal Realm. Only 27 events are reproducible in various regions, but diachroneity of most events seems to derive from different ammonite biostratigraphies applied in different areas. A very high stratigraphic resolution is achieved in Italy/France for the Pliensbachian to Lower Bajocian interval. The Sinemurian and Bathonian are characterized by the lowest resolution, and very few sections with ammonite control and/or favourable lithologies are available for improvement of nannofossil biostratigraphy.

This study confirms the potential of calcareous nannofossil biostratigraphy for dating Lower and Middle Jurassic successions as well as for intra- and inter-regional correlations.

Fabrizio CECCA, Annie V. DHONDT & Tamara N. BOGDANOVA

Abstract. The ammonite successions of Turkmenistan, particularly those of the Greater Balkhan and Tuarkyr areas, are considered references for the Aptian Stage. Six sections across the uppermost Barremian - basal Upper Aptian interval were studied in the Tuarkyr desert in October 1997,and ammonites and bivalves were collected. Data are compared with those from a section sampled by a Russian team in 1959. The stratigraphic distribution of the faunas in the sections is discontinuous, as the fossiliferous levels intercalate with terrigenous sediments. The ammonite faunas, at least in the intervals sampled, show low diversity and are dominated by the genus Deshayesites in the lower Aptian and the genus Epicheloniceras, associated with the less common Caspianites, in the basal upper Aptian. The Turkmenistan sections contain species present also in the Caucasus, England, Germany, France and Switzerland, indicating that the Turkmenian faunas reflect impoverishement rather than geographic isolation. The chronologic equivalence between the Turkmenian Epicheloniceras subnodosocostatum Zone and the Epicheloniceras martinioides Zone in England seems questionable because the Epicheloniceras-bearing beds of the Tuarkyr correspond to the upper part of the E. martinioides Zone, i. e. the Epicheloniceras buxtorfi Subzone. The bivalve fauna consists mainly of pteriids, Exogyrinae oysters and trigoniids. These groups undoubtedly indicate a very shallow, fairly warm and fully marine environment, typical of the Tethyan Lower Cretaceous. The heterodonts are too rare to give further bathymetric indications. None of the taxa indicate deep burrowing and all are assumed to be ?? littoral. The bivalve fauna shows strong affinities with that of the English Lower Greensand.

Marco Menichini

Abstract. In the Piobbico area (Pesaro, Central Italy, Inner Marchean Basin), outcrops of Paleogene to Early Miocene pelagic sediments are widespread and mainly consist of marls and marly limestones. In this paper two sections have been considered in the near Pieve d’Accinelli (PDA and PDA bis). A detailed biostratigraphic study was performed on planktonic foraminiferal assemblages using the standard zonations. PDA bis section spans from Early Oligocene to basal Aquitanian (Zone P20 to Subzone N4a), while PDA section is included in Zone N4 (Early Aquitanian).

"Standard" bioevents such as the LO (Last Occurrence) of "Globigerina" ampliapertura, Chiloguembelina spp., Paragloborotalia opima opima and the FO (First Occurrence) of Paragloborotalia kugleri and of Globoquadrina dehiscens, together with other "added" bioevents, have been identified. Moreover, several peaks in abundance occur such as a fair peak of Dentoglobigerina in the middle-upper portion of Subzone P21b, a strong increase in abundance of Tenuitella and Catapsydrax groups in Subzone P21b, an increase in abundance of Dentoglobigerina at the top of Zone P22, of Globoquadrina in Subzone N4a, of Globigerinoides spp. at the top of Subzone N4a and of Globoquadrina dehiscens in Subzone N4b.

A preliminary study of dinoflagellate cyst assemblages was carried out around Early Oligocene/Late Oligocene boundary. Two bioevents such as a peak in abundance of Svalbardella cooksonae at the base of Subzone P21b and the FO of Impaginodinium minor at the base of Zone P22 have been identified.

On the ground of a semiquantitative analysis of the planktonic foraminiferal assemblages, a paleoclimatic pattern has been tentatively inferred. This analysis suggests cool-temperate conditions at the top of Zone P20. In the lower part of the Late Oligocene the assemblages indicate the outset of very cool conditions, while the interval that spans Zone P22 to Subzone N4b is characterized by a generalized paleoclimatic instability.

Cengiz OKUYUCU

Abstract. The Hadim Nappe Carboniferous-Permian boundary and its fusulinacean-rich strata from the Çatalkatran Tepe stratigraphic section were studied.

The appearance of Sphaeroschwagerina sp. determines the Carboniferous-Permian boundary in this section. The presence of Pseudofusulina ? buzulukensis Dobrokhotova, Pseudofusulina parviflucta Zhou, Pseudofusulina hovunensis Davydov, Occidentoschwagerina (?) kosvaensis Echakov and Rugosofusulina stabilis Rauzer-Chernousova confirm the Asselian age.

A new Multidiscus ? species, Multidiscus ? tauridiana n. sp. was discovered from the Early Permian (Asselian) of Turkey (Hadim Nappe, Central Taurus).

Giovanni Bianucci & Walter Landini

Abstract. A partial skull of an odontocete cetacean from Middle Pliocene sediments of Monte Voltraio (Pisa Province, Tuscany, Italy) is examined. This fossil, erroneously referred to the family Ziphiidae and described in the past as holotype of the species Hyperoodon pusillus, is assigned here to the genus Kogia (family Kogiidae). The species Kogia pusilla is redescribed and compared to the living species K. breviceps and K. simus.

Phylogenetically, an old separation (at least in the Lower Miocene) of Kogiidae and Physeteridae is suggested. The lack of substantiated kogiid records until the Upper Miocene is probably due to the rarity of these cetaceans. Phyletic analysis within the Kogiidae is undertaken and supposed apomorphies in the morphology and/or the extension of the supracranial basin that houses the large air sacs and the spermaceti organ are considered.

Rossana Sanfilippo

Abstract. The new species Ditrupa brevis (Polychaeta, Serpulidae) is described from Middle Pliocene silts of southern Italy. It is also reported from Late Miocene sediments of southern Italy. The associated faunas suggest an infralittoral or upper-circalittoral distribution.

A morphometrical and microstructural analysis of tube was carried out. D. brevis closely resembles Ditrupa arietina but several morphometrical differences allow to discriminate the two species.

The Ditrupa tubes provide a substrate for a diversified epifauna. Their high density greatly affects species composition and diversity of soft-bottom communities.

It is concluded that Ditrupa can live in various positions with respect to the sediment surface, depending on local sedimentation rate and dynamics.

Antonietta Rosso

Abstract: A new species and a new subgenus Amphiblestrum (Aviculamphiblestrum) ruggeroi sp.n. are described from deep circalittoral-epibathyal bottoms from the Sicily Strait and the north-western Mediterranean. The new subgenus is created to distinguish, within Amphiblestrum, species with both gymnocystal adventitious and large interzooidal avicularia, both originating from basal pore chambers.