SHUZONG SHEN, G. R. SHI & KUIYU ZHU

Abstract. Twenty eight species belonging to twenty six genera and two unidentifiable genera are reported and figured from twelve isolated localities of the Dingjianzhai Formation in the Baoshan Block, western Yunnan, China. Four new species, Bandoproductus qigshuigouensis n. sp., Callytharrella dongshanpoensis n. sp., Trigonotreta semicircularis n. sp. and Punctocyrtella? yunnanensis n. sp., are described. Based on the stratigraphic distribution of the brachiopod species throughout the Dingjiazhai Formation, three assemblages are recognizable, which in ascending order are: Bandoproductus qingshuigouensis-Marginifera semigratiosa Assemblage (Asselian age), Punctocyrtella australis-Punctospirifer afghanus Assemblage (most likely latest Asselian-Early Sakmarian) and Callytharrella dongshanpoensis Assemblage (Late Sakmarian-Artinskian). The Early Permian Dingjiazhai brachiopod fauna as a whole demonstrates strong generic and specific links with those of Gondwanan and Perigondwanan faunas, but also demonstrates limited but significant links with those of the eastern Palaeotethyan faunas.

PETER BRACK, WOLFGANG SCHLAGER, MARCO STEFANI, FLORIAN MAURER & JEROEN KENTER

Abstract. First results and basic geological information of the Seceda Coring Project are reported. The Seceda project started with drilling of a well for scientific purposes. The core material is currently studied by an international group of geoscientists from different universities. Fundamental topics of the project are a thorough sedimentological and cyclostratigraphic analysis of the complete succession of Middle Triassic pelagic Buchenstein Beds in the northwestern Dolomites (Southern Alps, Italy) as well as their temporal relationship with coeval carbonate platforms. Complementary studies focus on stratigraphic correlation tools including bio-, litho- and magnetostratigraphy.

DAVID PETERS

Abstract. Traditionally, pterosaurs have been included within the Archosauriformes and many contemporary workers consider the Pterosauria the sister group to Lagosuchus, Scleromochlus and the Dinosauria. New analyses cast doubts on those relationships because nearly all presumed archosauriform or ornithodire "synapomorpies" are either not present within the Pterosauria or are also present within certain prolacertiform taxa. Recent examinations of the holotypes of Cosesaurus aviceps, Longisquama insignis and Sharovipteryx mirabilis suggest that many characters may be interpreted differently than previously reported. Results of several subsequent cladistic analyses suggests that these "enigmatic" prolacertiforms, along with the newly described Langobardisaurus, are sister taxa to the Pterosauria, based on a suite of newly identified synapomorphies.

FRANCESCO MACCHIONI

Abstract. Encrustation and/or bioerosion have been observed on both sides of several ammonites sampled from Lower-Middle Toarcian Rosso Ammonitico of the Umbria-Marche Apennines (Central Italy). The majority of these features are due to the activity of polychaete worms: the encrusting s.s. is due to serpulids, whilst bioerosion s. s. is similar to Maeandropolydora decipiens Voigt, and a third category of polychaetes has produced bioerosion-encrustation structures. The ornamentation features of the samples studied, allowed us to establish that the upper sides are preserved as composite moulds and the lower sides as internal moulds. The overprinting of the external shell structures on the internal infillings took place during burial diagenesis; the deformation style is plastic and only vertical, lateral deformation s being impeded.

The presence of boring and/or encrustation on the lower side of internal moulds is classically interpreted as evidence of reelaboration. Regarding these Toarcian specimens, the nature of the composite moulds would seem to confirm that the phenomena of encrusting and/or boring by polichaete worms occurred before the dissolution of the shells. Except in the cases of pure bioerosion, it is impossible to ascertain whether the shell was already infilled or not. The encrustation by polichaete worms probably occurred during post-mortem drifting or when the shell was exposed on the sea floor.

The similarity between the observed bioerosion phenomena and other hard and/or firm material borers gives us reason to think that the complete re-exhumation of the shell is not necessary to permit the boring action: however, a partial re-exhumation might have helped the borer to detect the presence of a shell test.

Jesús E. Caracuel , Paolo Monaco & Federico Olóriz ***

MILENA PIK-BIOLZI, PETER A. HOCHULI & ALEXANDER FLISCH

Abstract. X-ray computed tomography (CT) is a relatively new technology which has been used as a powerful research tool mainly by vertebrate palaeontologists. CT allows scientists to visualise internal features of fossils and rocks non destructively, just as medical scanners di for the human body. High-resolution industrial scanners provide cross sections of fossils at a resolution of 20 microns or less. We present the application of CT to two paleobotanical specimens: a petrified trunk of a Cycadeoidea from the Late Jurassic of England and a silicified cone Araucaria mirabilis from the Jurassic Cerro Cuadraro Petrified Forest in Patagonia, Argentina. In the three longitudinal and four cross-sections of the Cycadeoidea trunk, a multitude of internal structures could be observed, including pith, xylem, cortex, vascular bundles, floral cones and leaf bases. In central longitudinal and median transverse sections, the perfectly preserved cone Araucaria mirabilis pith, xylem, vascular bundles, seeds and ovuliferous scales are clearly visible. In order to test the resolution of the CT a second, less complete, but similarly well preserved specimen of A. mirabilis has been cut and sliced for a thin section.

IGNACIO ARENILLAS & JOSE’ A. ARZ

Abstract. The Parvularugoglobigerina eugubina Biozone (lowermost Danian) was defined at Gubbio (Italy) to precisely define the Cretaceous/Paleogene (K/P) boundary. It was defined by the total range of Pv. eugubina, but this small morphospecies presents some taxonomic problems. The Pv. eugubina holotype and the planktic foraminiferal assemblage of the Pv. eugubina type-sample at Ceselli (Ceselli 3) were revised to precise the biostratigraphic position of this biozone. Of the 21 morphospecies identified in Ceselli 3, 14 are early Paleocene species and 7 are possible Cretaceous survivors of the K/P boundary extinction event. To clarify the lowermost Danian bizonation, it was necessary to taxonomically revise Pv. eugubina and Pv. longiapertura, which have both been identified in this sample. Following the definition of Pv. eugubina and the original definition of the nominal biozone, the base of Pv. eugubina Biozone should be placed at the first appearance datum of the eponymous species and not at the first appearance datum of Pv. longiapertura.

Barbara Dall’Antonia^*

Abstract. The genus Oblitacythereis, type species Oblitacythereis (Oblitacythereis) mediterranea Benson, 1977, and the subgenera Oblitacythereis and Paleoblitacythereis are well defined by Benson (1977), who designated Carinocythereis ruggierii Russo, 1966 as type species of Paleoblitacythereis. The specimens figured and described as Carinocythereis ruggierii by Benson (1977), however, clearly differ from Russo’s species, and coincide well with Oblitacythereis sp. 3 Russo & Bossio, 1976, as stated by Bonaduce & Russo (1985). As a consequence of this misidentification the subgenus Paleoblitacythereis is subject to uncertainty and potential instability. The type species designated by Benson should be considered as a new nominal species and Carinocythereis ruggierii Russo, which actually belongs to Paleoblitacythereis, should be revised. The study of well-preserved specimens from some Miocene formations in southern Italy prompts the author to propose herein a systematic revision of the Italian representatives of the subgenus Paleoblitacythereis. Three species are discussed. These are: Oblitacythereis (Paleoblitacythereis) ruggierii (Russo, 1966), Oblitacythereis (Paleoblitacythereis) bossioi n. sp. ( = Oblitacythereis sp. 3 Russo & Bossio, 1976), here proposed as the new nominal type species of Paleoblitacythereis and, finally, Oblitacythereis (Paleoblitacythereis) apula n. sp., described as new. The systematic notes of each species are given with the bio-chronostratigraphical distribution resulting from the present study together with some palaeoecological remarks.

CARLOS ZAVALA

Abstract. Defined as a piggyback basin, the Plio-Pleistocene Sant’Arcangelo basin is one of the more recent onshore sedimentary basin of the Southern Apennines. Extensive field studies allow to reinterpret the whole stratigraphy of the basin in a more simple and significant way. Five unconformity-bounded units ("groups") have been recognised :

The (1) Catarozzo Group (late Pliocene) unconformably overlies pre-Miocene units, and it is composed of a flood-dominated fan-delta marine (C1) and restricted-marine (C2) systems bounded by a sharp contact with a total thickness up to 650 meters.

The (2) Aliano Group (late Pliocene - early Pleistocene) includes an up to 1,400 meters thick succession of flood-dominated fan-delta systems, with facies ranging from poorly organised alluvial conglomerates in the west to massive marine mudstones in the east. Two sub-units have been recognised, bounded by a regional unconformity, which shows an abrupt passage from marine (A1) to restricted-marine (A2) conditions.

The (3) Tursi Group (early-middle Pleistocene) reaches a thickness of 500 meters. It is composed of two sub-units, corresponding to alluvial fan (T1) and fan-delta (T2) systems. The alluvial facies of T2 (conglomerates) outcrop extensively in the Sant’Arcangelo basin, with equivalent flood-dominated shelfal sandstone lobes broadly developed in the Tursi area (Metaponto basin).

The (4) Profico and (5) Montalbano Jonico groups (middle Pleistocene) are partially time equivalents, and were developed in both sides of the Valsinni structure, which divided an early, broader Sant'Arcangelo basin into two sub-basins, the present "Sant'Arcangelo" and "Metaponto" basins. The Profico Group has a thickness of up to 300 m and consists of lacustrine strata overlying in angular unconformity the Tursi Allogroup in the "Sant'Arcangelo basin". The Montalbano Jonico Group on the other hand is made up of up to 300 m of fine-grained marine strata unconformably overlying the Tursi Group in the "Metaponto basin". All the units considered display clear evidences of synsedimentary tectonics.