A reappraisal of the Italian record of the Cretaceous pachycormid fish Protosphyraena Leidy, 1857

The genus Protosphyraena is known mainly from partial remains, consisting of isolated blade-like teeth, conical rostra and scythe-like pectoral fins. This paper provides a new insight into partial specimens of the genus Protosphyraena from the Cretaceous of NE Italy, housed in historical collections from local paleontological museums and previously poorly known to the international scientific community. The specimens are referred to the species Protosphyraena ferox, based on the morphology of the pectoral fin. This attribution is consistent with the paleobiogeographic distribution and stratigraphic range of this taxon. The Italian material provides new information about the distribution in time and space of Protosphyraena, which is relatively poorly known despite being an iconic taxon. The Italian remains, although fragmentary, contribute to fill a gap in the central Tethys record of the genus, whose range probably extended worldwide, considering also the genus Australopachycormus and its profound (possibly congeneric) similarities

UPPER CENOMANIAN FISHES FROM THE BONARELLI LEVEL (OAE2) OF NORTHEASTERN ITALY

The Bonarelli Level (BL) is a radiolarian-ichthyolithic, organic-rich marker bed that was deposited close to the Cenomanian/Turonian boundary (CTB) representing the sedimentary expression of the global Oceanic Anoxic Event 2 (OAE2). In northeastern Italy this horizon yielded fossil remains documenting a rather diverse ichthyofauna. The assemblage was studied by Sorbini in 1976 based on material from a single locality, Cinto Euganeo. Subsequently, other localities yielding fish remains have been discovered. Our revision also includes fish remains from three new fish-bearing localities, the Carcoselle Quarry, the Valdagno-Schio tunnel and Quero other than those from Bomba Quarry near Cinto Eugeneo. At least 28 taxa were identified, including nine previously not reported from the Bonarelli Level, namely: Scapanorhynchus raphiodon, Cretalamna appendiculata, Archaeolamna kopingensis, ‘Nursallia’ tethysensis, Belonostomus sp., Dixonanogmius dalmatius, ‘Protosphyraena’ stebbingi and the beryciform Hoplopteryx sp. The overall assemblage mostly consists of crossognathiforms, tselfatiiforms and aulopiforms. A comparison of the taxonomic diversity with coeval assemblages evidences a general similarity with nearby western Tethyan fish assemblages and especially with the Jebel Tselfat ichthyofauna, although some of the taxa are exclusively shared with the assemblages of the boreal realm (English Chalk, Westphalia and Saxony). However, additional information would be necessary to more properly define the main global ichthyogeographic patterns during the Cenomanian

THE BASAL COMPLEX STRATIGRAPHY OF THE HELMINTHOID MONTE CASSIO FLYSCH: A KEY TO THE EOALPINE TECTONICS OF THE NORTHERN APENNINES

Below the Monte Cassio helminthoid Flysch of the type locality, a well exposed basal complex outcrops in which Cenomanian turbidites of up to 200 m thickness are recognized. The bulk of these turbidites, named here Case Baruzzo Sandstone (CBS), consists of thick-bedded silty marlstones with a fine arenaceous base and represents the oldest siliciclastic input within the succession of the Cassio tectonic unit. The Case Baruzzo Sandstone lies unconformably on the Palombini shale of Hauterivian-Aptian age and on stratified packets of Jurassic-Cretaceous formations with Austroalpine affinity (Radiolarites, Aptici Shale and Maiolica). The Cenomanian CBS are unconformably overlain by Varicoloured Clay of Santonian - Campanian age and affected by soft-sediment deformations. The petrography of the CBS shows two petrofacies indicating (1) a direct provenance from their substrate and (2) an extrabasinal source similar to the terrigenous framework of the tectonically independent Coniacian-Santonian Ostia Sandstone outcropping southwest of the Cassio Unit. Because of its Cenomanian age the CBS must be considered as a siliciclastic wedge distinct from the younger Ostia Sandstone belonging to the Media Val Taro Unit and time correlative to the Varicoloured Clay of the Cassio Unit. The initiation of the turbidite sandstones terrigenous supply is Cenomanian into the Cassio Basal Complex (CBS), Coniacian into the Media Val Taro Unit (Ostia Sandstone) and Campanian into the more internal Gottero Unit (fine-grained turbidites interbedded within the Val Lavagna Formation). It is proposed that the relative positions of the highest tectonic units outcropping in the Emilian Apennines (i.e. Gottero, Media Val Taro and Cassio Units) during Late Cretaceous were not very different to the present setting, and that their tectono-stratigraphic evolution was related to Alpine-vergent accretionary wedges. The Alpine tectonic polarity should have controlled the westwards migration of the basinal depocentres and the evolution from the Adriatic-margin supply of the Cenomanian turbidites to the European-margin supply of the Maastrichtian turbidites. During the middle Eocene tectonic phase, before the counterclockwise apenninic rotation, the ophiolite-free Cretaceous Ligurian Units (i.e. Gottero, Media Val Taro, Cassio) overthrusted the Ligurian Units characterized by late Cretaceous ophiolitic detritus, known as Ottone and Caio Units, along a significant lithospheric discontinuity which acted as a transpressive fracture zone.&nbsp

Nuovi dati stratigrafici sull’ambra di Castelvecchio di Prignano (MO)

L’ambra dell’Appennino settentrionale è nota nel Bolognese fin dal XVII secolo (Masini, 1650; Boccone, 1684). La prima segnalazione dal Modenese risale a Strobel (1886), che parla di ambra da “Sassuolo nella provincia di Modena”; l’età di tale ambra rimane però indefinita. Skalski & Veggiani (1990), nella loro rassegna di ambre della Sicilia e dell’Appennino settentrionale, attribuiscono l’ambra del Bolognese (Scanello vicino a Loiano, provincia di Bologna) alla Formazione di Ranzano (o Loiano? L’equivalenza tra le due formazioni dichiarata dagli autori non è valida), assegnandole all’Oligocene inferiore. L’ambra del Modenese, più precisamente localizzata da Skalski & Veggiani (1990) nelle “Castelvecchio sandstones” (sic), vicino a Prignano (MO), viene dagli stessi autori attribuita alla Formazione di Ranzano e quindi datata anch’essa all’Oligocene inferiore. Angelini & Bellintani (2005), nella loro rassegna sulle ambre di provenienza archeologica dell’Italia settentrionale, hanno analizzato con metodi spettroscopici ambre di Scanello Bolognese (BO) e di Castelvecchio di Prignano (MO), evidenziando una marcata differenza tra i campioni provenienti dal Bolognese e dal Modenese. Inoltre, l’attribuzione dell’ambra di Castelvecchio all’Oligocene non è sostenuta da alcun dato diretto, se si esclude una possibile somiglianza litologica tra gli strati campionati e quelli della Formazione di Ranzano. In sintesi, l’attribuzione di un’età oligocenica all’ambra proveniente da Castelvecchio di Prignano risulta quantomeno dubbia. Un affioramento contenente ambra da questa località del Modenese è stato recentemente localizzato con precisione, misurato e campionato. L’esposizione comprende circa 5 m di successione, costituita da arenarie più o meno calcaree intercalate a livelli siltitici e argillosi variamente bioturbati. All’interno dei livelli arenitici (di solito nella loro parte superiore) si trovano livelli ricchi di frustoli vegetali, contenenti ambra e pezzi di carbone. L’ambra si presenta in frammenti e gocce, generalmente di colore rosso molto scuro, di dimensioni che vanno da 0,5 cm fino a oltre 6-7 cm. Al momento non sono state osservate inclusioni animali, soltanto alcuni minuscoli frammenti carboniosi che rendono scuro il colore della resina fossile. Sull’ambra è stata effettuata l’analisi agli infrarossi a trasformata di Fourier (FTIR). Per chiarire il contesto stratigrafico della resina fossile di Castelvecchio, sono stati raccolti campioni per lo studio del plancton calcareo, che ha consentito di attribuire i livelli fossiliferi alla parte superiore del Maastrichtiano. Questo dato diretto ha permesso, per la prima volta, di far risalire un’ambra dell’Appennino settentrionale al Cretaceo, diversamente da quanto finora riportato in letteratura. Bibliografia: Angelini I. & Bellintani P. (2005). Archaeological ambers from Northern Italy: an FTIR-DRIFT study of provenance by comparison with the geological amber database. Archaeometry, 47: 441-454. Boccone P. (1684). Osservazioni naturali ove si contengono Materie Medico-Fisiche, e di Botanica, Produzioni Naturali, Fosfori diversi, Fuochi sotterranei d’Italia, et altre curiosità. Manolessi Stamp., Bologna, p. 156-157. Masini A. (1650). Bologna perlustrata. Zenero, Bologna, p. 180. Skalski A.W. & Veggiani A. (1990). Fossil Resin in Sicily and the Northern Apennines: Geology and Organic content. Prace Muzeum Ziemi, 41: 37-49. Strobel P. (1886). L’ambra padana. Bullettino di Paletnologia Italiana, 12: 42-49

Morphology and paleobiology of the Late Cretaceous large-sized shark Cretodus crassidens (Dixon, 1850) (Neoselachii; Lamniformes)

The definition of the Cretaceous shark genus Cretodus Sokolov, 1965 is primarily based on isolated teeth. This genus includes five species. Among these, Cretodus houghtonorum Shimada and Everhart, 2019 is the only species based on a partially preserved skeleton. Here, the taxonomic attribution of a virtually complete skeleton of Cretodus from the Turonian of northeastern Italy is discussed, together with a few specimens from the Turonian of England. One of the latter is investigated through micropaleontological analysis to determine its stratigraphic position. The material is referred to Cretodus crassidens (Dixon, 1850), the diagnosis of which is emended herein. The dentition is tentatively reconstructed, exhibiting strong similarities with congeneric species, although it differs in having strong vertical folds on the main cusp labial face, a mesiodistally broad tooth aspect, weak and well-spaced 'costulae' at crown base, and a different dental formula in the number of parasymphyseal and lateral rows. Some tooth malformations are interpreted as feeding-related or senile characters. The Italian specimen suggests that Cretodus crassidens had a wide and laterally expanded mouth and head, a stout body, and attained a gigantic size. Cretodus crassidens was a moderate-speed swimming shark ecologically like the extant tiger shark Galeocerdo cuvier (Péron and Lesueur in Lesueur, 1822). The age estimate from vertebral-band counting suggests that the Italian individual was at least 23 years old and the growth model indicates a longevity of 64 years and a maximum attainable total length of 9-11 m. Cretodus crassidens occurs both in Boreal and Tethyan domains, implying a broad paleobiogeographic distribution and a preference toward offshore settings

THE MIDDLE EOCENE CLIMATIC OPTIMUM (MECO) IMPACT ON THE BENTHIC AND PLANKTIC FORAMINIFERAL RESILIENCE FROM A SHALLOW-WATER SEDIMENTARY RECORD

We present here new quantitative analyses of planktic and benthic foraminifera to assess the impact of the Middle Eocene Climatic Optimum (MECO, ~40 Ma) on these biotic groups studied along a shallow-water succession rich in larger benthic foraminifera (Sealza, Liguria, NW Italy). The MECO is one of the major Eocene global warming events, characterized by ~4–6°C warming, shifts in the global carbon cycle, and rise in atmospheric pCO2. The Sealza succession is interpreted as the product of a drowning ramp influenced by tectonic activity and provides an exceptional chance to compare biotic variations in shallow-water assemblages with deep-water communities across the MECO. In the section, the MECO interval is tentatively constrained by stable isotope oxygen data and calcareous plankton biostratigraphy. The marked decline in abundance of the epifaunal benthic Cibicidoides across the lower-middle part of the MECO suggests a decrease in oxygenation at the seafloor. Further evidence of oxygen depletion is the increase in organic matter content (TOC) of the sediment and the presence of infaunal genera Uvigerina and Bolivina. The planktic foraminiferal assemblages record the MECO warming in the upper water column as the mixed-layer warm index genera Acarinina and Morozovelloides markedly increase in abundance. In the post-MECO interval, here poorly exposed, cooler conditions are indicated by the dominance of the cold-water index genus Subbotina. Remarkably, Acarinina decline in abundance in the upper MECO interval and never recover. The MECO perturbance permanently impacted the benthic and planktic communities at Sealza that exceeded the tipping point to move to a new regime, thus proving the fauna to be not resilient, but also not recording any extinctions.

The 10Be record as a proxy of paleomagnetic reversals and excursions: A Mediterranean perspective

The 10Be/9Be ratio is acknowledged as an effective tool for establishing the stratigraphic position of paleomagnetic excursions. Still, our data suggest that, in particular depositional settings, the interplay between climate, sedimentation and oceanography may jeopardize a realistic depiction of the natural 10Be/9Be record

Proposal for the Global Boundary Stratotype Section and Point (GSSP) for the Priabonian Stage (Eocene) at the Alano section (Italy)

The base of the Priabonian Stage is one of two stage boundaries in the Paleogene that remains to be formalized. The Alano section (NE Italy) was elected by consensus as a suitable candidate for the base of the Priabonian during the Priabonian Working Group meeting held in Alano di Piave in June 2012. Further detailed research on the section is now followed by a formal proposal, which identifies the base of a prominent crystal tuff layer, the Tiziano bed, at meter 63.57 of the Alano section, as a suitable candidate for the Priabonian Stage. The choice of the Tiziano bed is appropriate from the historical point of view and several bio-magnetostratigraphic events are available to approximate this chronostratigraphic boundary and guarantee a high degree of correlatability over wide geographic areas. Events which approximate the base of the Priabonian Stage in the Alano section are the successive extinction of large acarininids and Morozovelloides (planktonic foraminifera), the Base of common and continuous Cribrocentrum erbae and the Top of Chiasmolithus grandis (nannofossils), as well as the Base of Subchron C17n.2n and the Base of Chron C17n (magnetostratigraphy). Cyclostratigraphic analysis of the Bartonian-Priabonian transition of the Alano section as well as radioisotopic data of the Tiziano tuff layer provide an absolute age (37.710 – 37.762 Ma, respectively) of this bed and, consequently, of the base of the Priabonian Stage