VOLUME 106 (2000) N. 2
TANYSTROPHEUS (ARCHOSAUROMORPHA, PROLACERTIFORMES) REMAINS FROM THE TRIASSIC OF THE NORTHERN FRIULI (NE ITALY)
FABIO MARCO DALLA VECCHIA
Abstract. The first diagnostic remains of the large prolacertiform Tanystropheus are reported from northeastern Italy. They include a proximal caudal vertebra from the Middle Triassic of Aupa valley (Udine, Friuli) and a cervical vertebra from the Carnian of Fusea (Udine). The cervical vertebra represents the first record of Tanystropheus in the Carnian and is the geologically youngest occurrence other than the Norian T. fossai. Tanystropheus lived along the coasts of the northwestern Tethys during the Late Triassic while it disappeared in Central Europe where continental environments were prevailing.
A NEW, EARLY CROWN-GROUP ASTEROID (ECHINODERMATA) FROM THE NORIAN (TRIASSIC) OF NORTHERN ITALY
Daniel B. Blake, Andrea Tintori, & Hans Hagdorn
Abstract. Noriaster barberoi gen. et. sp. n. is based on a single specimen from the Calcare di Zorzino (Norian, Triassic) of northern Italy. A member of the surviving Poraniidae (Valvatida; Echinodermata), N. barberoi is the oldest-known species assignable to a Jurassic and younger family and the first such species known from the Triassic. No Paleozoic species with close affinities with crown-group families has been recognized. Noriaster and the slightly older Triassic genus Trichasteropsis from the Muschelkalk of Germany together indicate that the diversification of crown-group asteroids was well underway at least by Middle and Late Triassic time.
Phylogeny of crown-group asteroids is problematic because extant familial-level taxa are morphologically divergent, and they exhibit comparatively few uncontested characters that clearly indicate phylogenetic affinities and sequence. Familial assignment of Noriaster is supported by a new cladistic analysis.
To the student of living asteroids, the appearance of a living Noriaster would be remarkable only because it would seem so commonplace. To the extent that form correlates with function, Noriaster suggests that modern asteroid life modes emerged quite promptly during the Mesozoic asteroid diversification.
BIRD-LIKE HEAD ON A CHAMELEON BODY: NEW SPECIMENS OF THE ENIGMATIC DIAPSID REPTILE MEGALANCOSAURUS FROM THE LATE TRIASSIC OF NORTHERN ITALY
Abstract. Two new Megalancosaurus specimens collected from the Norian (Late Triassic) Calcare di Zorzino (Zorzino Limestone) Formation (Bergamo, Lombardy, Northern Italy), and from the coeval Dolomia di Forni (Forni Dolostone) Formation (Udine, Friuli, North-eastern Italy) improve our knowledge of skeletal anatomy and mode of life of this genus. Morphology of observable skull elements and cervical vertebrae in one of the new specimens shows some resemblance to the possible Triassic bird Protoavis, while the postcranial skeleton of Megalancosaurus is completely non-avian. This may suggest that either Megalancosaurus and Protoavis developed a similar neck structure as a response to the same functional requirement, or that part of the disarticulated material ascribed to Protoavis may indeed belong to a Megalancosaurus-like reptile.
Megalancosaurus shows a very high adaptation to arboreal life and a peculiar feeding strategy. Recent suggestions that Megalancosaurus may have been a glider and a possible model for bird ancestry are discussed. Some skeletal features of Megalancosaurus may indeed be interpreted as gliding adaptation, but evidence is weak, and if this reptile was a glider, however, its gliding bauplan should have been completely different from the one usually accepted for bird ancestors, showing instead more morphological similarities with gliding squirrels, phalangeriids and putative ancestors of bats and pterosaurs (according to a non cursorial model for these latter).
A LATE TRIASSIC OSTRACOD ASSEMBLAGE FROM THE QUATTERVALS NAPPE (AUSTROALPINE, NORTHERN ITALY)
SYLVIE CRASQUIN-SOLEAU, FABRIZIO BERRA & ROBERTO RETTORI
Abstract. The up to 1200 m thick Norian succession of the Quattervals Nappe (Central Austroalpine, Italy) documents a tectonically-driven passage from intertidal facies (Dolomia Principale-Hauptdolomit), represented by early-dolomitized bedded to massive gray dolostones, to intraplatform basin sediments (Pra Grata Formation and Quattervals Limestone), consisting of resedimented dark limestones and thin bedded laminated limestones, alternating (mainly in the Pra Grata Formation) with intraformational breccias containing abundant shallow-water facies. The transitional and basinal facies contain an interesting ostracod assemblage, beside bioclastic layers containing shallow-water and upper slope skeletal grains.The ostracod fauna is rich in specimens belonging to few genera, denoting restricted environmental conditions characterized by variations of salinity and low oxygenation. Despite the intense deformation and recrystallization related to the Alpine tectonics, the paleontological analysis of the ostracod assemblage from the base of the Quattervals Limestone, allowed the identification of the two new species of ostracods Rhombocythere dimorphica and Kerocythere quattervalsi in association with other already known forms.
Revision and re-documentation of M. Airoldi's species of Archaeolithothamnium from the Tertiary Piedmont Basin (NW Italy)
Grazia Vannucci, Michele Piazza, Patrizia Fravega & Daniela Basso
Abstract. Airoldi (1930, 1932) described twenty-three fossil Corallinales (Rhodophyta) from the Oligocene of the Tertiary Piedmont Basin (NW Italy), containing thirteen new species. In this paper Archaeolithothamnium praeerithraeum Airoldi 1932 and Archaeolithothamnium statiellense Airoldi 1932 are re-documented and re-described. The features observable in the sporangial compartments allowed to attribute both species to the genus Sporolithon.
THE OLIGOCENE MOLLUSC FAUNA OF THE PIEDMONT BASIN (NORTH-WESTERN ITALY)
I. SCAPHOPODA AND ARCHAEOGASTROPODA
M. Cristina Bonci, Gabriella Cirone, Bruna Merlino & Luca Zaliani
Abstract. The aim of the present work is to study the Oligocene Scaphopoda and Archaeogastropoda of the Tertiary Piedmont Basin (T.P.B.), aiming towards an overall revision of the Oligocene mollusc fauna of this Basin. Five taxa of Scaphopoda and twenty-eight taxa of Archaeogastropoda have been analysed; among these a new species of Nerita (Theliostyla) is proposed.
New observations on the anatomy of the fossil calcareous alga Subterraniphyllum Elliott
GRAZIA VANNUCCI, DANIELA BASSO & PATRIZIA FRAVEGA
Abstract. New specimens of Subterraniphyllum thomasii Elliott collected from the Oligocene Molare Formation outcropping close to Alessandria (northern Italy) and studied in thin sections and by SEM showed that primary pit-connections, cell fusions, uniporate conceptacles and geniculate branches were present. These new observations collectively confirm the placement of S. thomasii within the geniculate Corallinaceae. Although S. thomasii share many diagnostic characters with the Corallinoideae, in particular with the tribe Corallineae (apical position of uniporate conceptacles, number of medullary cell layers) and some similarity with the Metagoniolithoideae (medullary cells gradually merging into the cortical cells) the lack of information on genicula and the observed details of insertion of branches do not allow to determine the suprageneric disposition of S. thomasii.
GEOLOGICAL EVOLUTION AND BIOCHRONOLOGICAL EVIDENCES OF THE MONTE RICCIO SECTION (TARQUINIA, CENTRAL ITALY).
Ilaria Mazzini, Paolo Paccara, Carmelo Petronio & Raffaele Sardella
Abstract: The geological evolution of the area of M.te Riccio for the Plio-Pleistocene time span has been pointed out. The M.te Riccio area was probably an high during Gelasian-Santernian times. The stratigraphical sequence shows the passage from a coastal marine environment during Pliocene, to a coastal environment during Early Pleistocene (testified by evidences of shorelines) to continental conditions during the upper part of Pleistocene. The analysis of the mammal bones coming from a level overlying a marine formation ("Macco" auct.) allow us to ascribe the faunal association to the late Villafranchian (Tasso F.U.) referable to the beginning of the Pleistocene. It is the first signalation of an Early Pleistocene mammal fauna in the Northern Latium.