LARDAROCERAS GEN. N., A NEW LATE ANISIAN AMMONOID GENUS FROM THE PREZZO LIMESTONE (SOUTHERN ALPS)

On the basis of ammonoids collected in the uppermost part of the Prezzo Limestone (Anisian), the new genus Lardaroceras and two new species L.  krystyni (type species) and L. pseudohungaricum are described; a third one is left in open nomenclature. The genus Lardaroceras comprises involute and compressed ceratitids, whose subtrapezoidal whorl section is characterized by an evident periumbilical margin and a rounded ventral keel. The ornamentation is made of umbilical and lateroventral nodes, to which sometimes lateral nodes are added, and of lightly proverse and sinuous, primary, intercalatory and bifurcate ribs. The very distinctive suture line is subammonitic. The two species, L. krystyni and L. pseadohungaricam, differ mainly in the ornamentation and in the adult body chember: the former has umbilical and lareroventral nodes and its ornamentation fades on the adult body chamber, the latter has also lateral nodes and its ornamentation strengthens in the latest stage of growth. Because of the suture line the genus is attributed to the subfamily Beyrichitinae. The stratigraphic significance of the new genus is also discused

CAST PHOTOCOPYING: A SIMPLE METHOD FOR THE ANALYSIS AND THE ILLUSTRATION OF THE OUTLINE OF CEPHALOPOD SHELLS

A simple way to get accurate figures of the outline of cephalopod shells is hereunder described. It consists in photocopying carefully sectioned casts made of plaster. The usefulness of the method is evaluated in comparisons with the other available techniques

TAXONOMY,STRATIGRAPHY AND PHYLOGENY OF THE NEW GENUS LANCEOPTYCHITES (AMMONOIDEA, ANISIAN)

For the first time a population analysis of compressed Ptychitidae (Ammonoidea) bed-by-bed collected from Prezzo Limestone (Upper Anisian, Southern Alps) is performed. The analysis allows to demonstrate that within some populations of compressed ptychitids during the growth the venter may become subacute/fastigate and the section lanceolate. This modification is not due to growth anomalies, as sometimes believed in literature, but is a normal ontogenetic development. The ammonoids with this peculiar ontogeny are moved from the genus Flexoptychites, that groups the compressed ptychitids with rounded venter, into the new genus Lanceoptychites. The new genus is a secondary descendent of Flexoptychites and comprises 4 species: L. velox (type) sp. n., L. styx sp. n., L. indistinctus (Mojsisovics) and L. charlyanus (Diener). L. styx and its peramorphic descendant L. velox are stratophenetic species. They are described from the Prezzo Limestone, where they are confined to the middle part of the Paraceratites trinodosus zone (Illyrian). No bed-by-bed information is available for L. indistinctus (Mojsisovics) and L. charlyanus (Diener). These morphospecies are revised on the basis of the type material.&nbsp

Editorial [BOLLETTINO DELLA SOCIETÀ PALEONTOLOGICA ITALIANA, Vo. 54, 2015]

Editorial to the Volume

Editorial [BOLLETTINO DELLA SOCIETÀ PALEONTOLOGICA ITALIANA, vol. 55(2), 2016]

Editorial to the Volume

LADINIAN/CARNIAN AMMONOIDS AND CONODONTS FROM THE CLASSIC SCHILPARIO-PIZZO CAMINO AREA (LOMBARDY): REVALUATION OF THE BIOSTRATIGRAPHIC SUPPORT TO CHRONOSTRATIGRAPHY AND PALEOGEOGRAPHY

This area played a key role in defining Middle Triassic stratigraphy. In the nineteenth century the study of several ammonoids collected in the Wengen Formation served as a basis for the definition of the Longobardian substage of the Ladinian. Moreover, during the 1960’s the modern Triassic Lithostratigraphy of Lombardy was founded on sections from this area. The present study represents the first bed-by-bed sampling of this area and is focused mainly on the Wengen Formation and Pratotondo Limestone. In particular, conodonts were found in both units for the first time. The age of some Middle Triassic formations is revised: the top of the Wengen Formation belongs definitively to the Lower Carnian in a sizeable portion of the study area. The overlying carbonate platform, previously attributed to the Upper Ladinian Esino Limestone, is instead Carnian and is coeval to the Breno Formation in the Southern Camonica Valley. the Pratotondo Limestone is dated Late Ladinian/Early Carnian, while the overlying Lozio shale is Carnian. These new data contradict the equivalence "Wengener Schichten" = Archelaus Zone = Longobardian so common in the literature. We demonstrate that the Regoledanus Zone represents a great part of the Wengen Formation. Moreover, at the top of the Wengen Formation the ammonoid and conodont fauna represents the early Carnian Daxatina or Aon Zone. The biochronostratigraphic revision of the basinal formations requires modification of both the chronostratigraphic schemes and the paleogeographic history of the lombardian Southern Alps during Ladinian-Carnian time.&nbsp

MIDDLE TRIASSIC CERATITIDS (AMMONOIDEA) COLLECTED BY C. RENZ FROM HYDRA (GREECE)

This paper  is focused on the description of an assemblage of ceratitids collected more than 50 years ago by C. Renz from the Han-Bulog Limestone of Hydra (Greece), up to the present never described. The identified forms are Asseretoceras camunum  (Assereto, 1963), Megaceratites aff. fallax Balini, 1992b, Ronconites sp. n. A, "Kellnerites"  sp. ind., Nevadites sp. ind. Two ceratitids of uncertain attribution are also described. These species have only paleoecological implications, since a stratigraphic bed-by-bed sampling has not been performed. A. camunum and the genera Megaceratites and Ronconites are reported for the first time from the Han-Bulog Limestone. Megaceratites and Ronconites are also reported for the first time out of the Southern Alps

LATE CARNIAN-EARLY NORIAN AMMONOIDS FROM THE GSSP CANDIDATE SECTION PIZZO MONDELLO (SICANI MOUNTAINS, SICILY)

A small collection of ammonoids from the Upper Triassic Scillato Formation at Pizzo Mondello (Agrigento, Sicily) is studied. The specimens were collected in a framework of a project aimed at providing an integrated high-resolution bio-chronostratigraphic support to the Upper Carnian-Norian magnetostratigraphic scale defined at this site, that is located in an historical area from which G.G. Gemmellaro collected the Upper Triassic of ammonoids monographed at the beginning of the XX century. The specimens from Pizzo Mondello were bed-by-bed sampled and represent the first collection of Upper Triassic ammonoids described from Sicily since Gemmellaro time. Quite several levels of the Pizzo Mondello section yielded ammonoids, but very few levels have provided more than one specimen. Due to the scarcity of specimens the taxonomic analysis has been complex because Gemmellaro, who described 166 new species, did not explain the variability of many of his taxa. Sixsteen taxa belonging to eleven genera are described. They include Placites sp. ind., Discotropites plinii (Mojsisovics), Anatropites sp., Microtropites cf. paronai, Metathisbites cf. affinis, Hyattites aff. praefloridus, Projuvavites boehmi (Gemmellaro), Projuvavites inflatus (Gemmellaro), Gonionotites cf. italicus, Gonionotites aff. recuperoi, Dimorphites noricus n. sp., Dimorphites selectus Mojsisovics, Dimorphites sp., Pregriesbachites n. gen. , P. bukowskii (Gemmellaro), Discophyllites insignis. Among the new taxa, Dimorphites noricus n. sp. formalizes the nomen nudum “Dimorphites n. sp. 1” quoted in literature for several years, that is index of the lowest subzone of the Norian stage.The small collection document the Discotropites plinii and Gonionotites italicus subzones of the uppermost Carnian Spinosus Zone and the Dimorphites noricus and D. selectus subzones of the Jandianus Zone, the first zone of the Lower Norian. This chronostratigraphic classification firmly tie the Pizzo Mondello succession to the Tethyan chronostratigraphic scale, and is crucial for the calibration of the Halobia and conodont bioevents identified in the section. The chronostratigraphic correlations based on ammonoids of the Pizzo Mondello section with Feuerkogel (Austria), Jomsom (Nepal), West Union Canyon (Nevada, USA) and Black Bear Ridge (British Columbia, Canada) is discussed. These are the most complete ammonoid-bearing sections in the world spanning the Carnian/Norian boundary, but all of them show a discrete distribution of ammonoid-bearing beds across the boundary. Ammonoid will not provide the primary marker event for the definition of the GSSP of the Norian, but they are crucial for the selection of the most significant events.

THE DISCOVERY OF AMMONOIDS IN THE CUNARDO FORMATION (VARESE). A NEW CHRONOSTRATIGRAPHIC INTERPRETATION

The discovery of ammonoids at the top of the Cunardo Formation allows the revision of the chronostratigraphic position of the unit. Detoniceras, Argolites and Anolcites testify the Archelaus Zone. The age of the unit is then Ladinian instead of Carnian, as reported in literature