Grazia Vannucci

Fossil and living corallinaceans related to the mediterranean endemic speciesLithophyllum racemus (Lamarck)Foslie

SummaryNew observations on asexual and sexual thalli of the Mediterranean speciesLithophyllumracemus and description of its variability in a Tyrrhenian population have led to reinterpretation of the features of some fossil and living taxa. The external appearance and the reproductive and vegetative anatomy of the fossil speciesLithophyllum viennotii corresponds to tetrasporangial plants ofL. racemus. The fossil speciesLithophyllum microsporum, whose holotype is redescribed here, represents a sexual stage ofL. racemus, probably the carpogonial/carposporangial plants.Consequently, the stratigraphical distribution ofL. racemus is widened back to the Aquitanian, and the species can thus be considered a Mediterranean paleoendemic. No character was found supporting the distinction ofLithophyllum duckeri fromL. racemus, therefore this species is also considered conspecific withL. racemus.

Rhodolith-rich lithofacies of the Porto Badisco Calcarenites(upper Chattian, Salento, southern Italy)

This study describes the rhodolith-rich lithofacies of the Porto Badisco Calcarenites, an upper Chattian rhodalgal/larger foraminiferaldominated unit exposed in the southern part of the Apulia Carbonate Platform (Salento Peninsula, Italy). The lensoid rhodolith-rich lithosome at the base of the studied section is made of rhodolith rudstone and floatstone which infill a channel-like depression inherited from the substrate. Changes in the texture of the rhodolith facies and in the inner structure of the rhodoliths reflect variations in submarine current velocity across the section of the channel. Inherited topography controlled both the locus and the mode of rhodolith accumulation. The rhodolith lithosome is bounded by a flat surface above which rhodoliths are notably absent and beds are tabular. This implies that rhodolith accumulation ended as soon as substrate topography was completely levelled off. The taxonomic composition of the red algal and larger foraminiferal assemblages suggests that the rhodolith-rich unit deposited in the oligophotic zone. The abundance of tropical genera among the coralline algae (Lithoporella and Sporolithon) and the high diversity of larger foraminiferal assemblages indicate that the deposition of the Porto Badisco Calcarenites took place in the warm waters of the tropical to subtropical zone

Climatic and tectonic control on the distribution of the Oligocene reefs of the Tertiary Piedmont Basin (NW Italy)

The Tertiary Piedmont Basin (TPB) stretches along the Piedmont-Liguria border and is a late- to post-orogenic basin that evolved in a piggy-back position on the Monferrato thrust belt. Its depositional story is strongly controlled by tectonic and eustatic events. The basin was filled with mainly marine sediments (upper Eocene-upper Miocene), which unconformably overlie the Ligurian Alps and the Northern Apennines. The early stage of sedimentation of TPB records a transgressive phase (time-transgressive from the eastern to the western sectors, upper Eocene-upper Oligocene), characterized by the deposition of alluvial fan and fan delta siliciclastic conglomerates and sandstones, marine shallow-water coarse to fine grained siliciclastic sediments, and reef limestones. The TPB reefal buildups, which developed close to the paleoshoreline, have a lower Rupelian-middle Chattian stratigraphic distribution and are restricted to the central part of the southern margin of the TPB. The Valzemola-San Bernardino reef is the younger and the westernmost settlement, while the Val Lemme reef represents the older and easternmost one. The depicted stratigraphic and geographic distribution may be the result of a combined climatic and tectonic control. The lack of reef settlements west of Valzemola-Bric S. Bernardino may be due to climatic condition unfavourable for the reef development (temperature cooler than those of the early Rupelian-middle Chattian time interval). The absence of reefs in the area to the east of Val Lemme may be the consequence of bottom instability and high sedimentation rates (unfavourable conditions for the reef development) caused by the syn-sedimentary tectonic activity along the Scrivia fault, during the time interval spanning from the late Eocene to the early Oligocene (notwithstanding the favourable climatic conditions). Finally, the age of the older reefal complex, i.e. early Rupelian (Val Lemme), gives an obvious constraint to the age of the end of the N-vergent thrusting phase of the Voltri Unit onto the flysch units and its sedimentary cover.

Coralline algae as environmental indicators: a case study from the Attard member (Chattian, Malta)

ABSTRACT We investigated the distribution of the red algae assemblages along the depositional profile of the Attard carbonate ramp of Malta (Chattian). The Attard member is ascribed to the Lower Coralline Limestone Formation characterized by 4 members: Maghlaq, Attard, Xlendi and Il Mara. Coralline algae are present in the inner and middle ramp environments of the Attard member. Sporolithaceans and melobesioids dominate the inner ramp, while mastophoroids and peyssonneliaceans are subordinate. In the middle ramp the association of red algae is characterized by an increase of sporolithacenas and a decrease of melobesioids, mastophoroids and peyssonneliaceans. These assemblages are related to the depth gradient existing from the inner relatively shallow to the progressively deeper middle ramp. However, transportation of red algae down slope may have had an effect on the red algae associations. The shape, morphology and structure of rhodoliths in the inner ramp environment are indicative of high-energy conditions. Nevertheless localized sectors of inner ramp are characterized by morphologies typical of low energy probably related to the presence of areas colonized by seagrass. Rhodoliths from the middle ramp have characteristics of moderately highenergy. The presence of Sporolithon Heydrich and Lithoporelk (Foslie) Foslie indicates that the production of carbonate took place under tropical conditions. We suggest that the Mg/Ca ratios may had a control on the flourishing of coralline algae in the Oligocene carbonate factories situated in oligo- to mesotrophic conditions, whereas during Early to Middle Miocene times the trophic conditions were one of the main controlling factor.

REVISION AND RE-DOCUMENTATION OF M. AIROLDI'S SPECIES OF LITHOPHYLLUM FROM THE TERTIARY PIEDMONT BASIN

The species originally attributed by Airoldi (1932) to the genus Lithophyllum ( L. perrandoi , L. ligusticum , L. personatum and L. desitum ) are here re-examined on the basis of the original material, original descriptions and illustrations. L. perrandoi and L. ligusticum are considered to be conspecific and questionably retained in the genus Lithophyllum . We give priority to the name ? L. perrandoi Airoldi to honour the priest Don Perrando, who collected most of the fossils conserved in the Dip.Te.Ris of Genova. L. personatum and L. desitum do not belong to the genus Lithophyllum as presently circumscribed. L. personatum Airoldi is a female/carposporangial plant of a mastophoroid species resembling Spongites fruticulosus Kutzing, and therefore we retain a dubitative identification with the new combination ? Spongites personatus (Airoldi). L. desitum is here placed in the genus Mesophyllum under the new combination Mesophyllum desitum (Airoldi). On the basis of its vegetative and reproductive features, M. desitum comb. nov. is here considered conspecific with Mesophyllum obsitum Airoldi. Pdf

THREE NEW SPECIES OF CORALLINE ALGAE (GENERA LITHOTHAMNION AND LITHOPHYLLUM ) FROM THE TERTIARY PIEDMONT BASIN

Two new species of the genus Lithothamnion and one of Lithophyllum were discovered in the burdigalian section of Bric Cardinelle (Visone Formation, Tertiary Piedmont Basin). The holotypes are present in rhodoliths coming from oncolitic rudstone or calciruditic bodies. The new species are characterised by morphological features and dimensions of cells that are clearly different from those of the other recorded species of Lithothamnion and Lithophyllum .

Quantification of the coralline carbonate from a Serravallian rhodolith bed of the Tertiary Piedmont Basin (Stazzano, Alessandria, NW Italy)

ABSTRACT Digital photographs of the surface of Serravallian rhodolith-bearing strata from Stazzano (Tertiary Piedmont Basin) Italy have been elaborated by Image-J opensource software (U.S. National Institutes of Health — NIH), to obtain a map of the algal surface in each photograph. The 33 images in the 7 m-thick outcrop, covering a total of 11.53 m2, were complemented by data on rhodolith shape, structure, composition and taphonomy. The Serravallian rhodolith body was produced in a long-lasting infralittoral sedimentary environment and then transported into deeper water by slumping. Although biological and geological definitions of rhodolith-dominated facies are inconsistent in some respects, the image analysis described here allows direct comparison of percentages of rhodolith dominance in discrete fossil rhodolith facies and their living counterparts. The procedures involved are both rapid and inexpensive, so the method appears very useful for carbonate quantification. The calculated algal cover, based only on rhodoliths > 2 cm, ranges from 11.9 to 59.7% (mean 27.3%). The carbonate production rate of the Serravallian rhodolith bed was probably in the range 55 to 136.3 g CaCO3 m-2yr-1 as calculated for a Brazilian present-day analogue.

Subterraniphyllum and free-living Neogoniolithon (coralline algae) from the Oligocene reef facies of Costa d’Ovada (Tertiary Piedmont Basin, Alessandria, NW Italy)

The present study examines the siliciclastic sediments and reef limestone of the Oligocene transgressive event of the Tertiary Piedmont Basin outcropping in the area of Costa d’Ovada (Alessandria, Southern Piedmont, NW Italy). Seven lithostratigraphic sections have been studied. On the basis of the lithostratigraphic evidence, sedimentary architectures and structures, and paleontological data a paleoenvironmental reconstruction is suggested. The reef of Costa d’Ovada rests on siliciclastic marine sediments and was buried by siliciclastic sandy and/or gravely shallow marine deposits. This reef was built in warm tropical or subtropical, clear and very shallow waters, on sandy gravely, moderately exposed bottoms. It might be interpreted as a patch reef developed close to the coastline. In the depicted paleoenvironmental frame, an unusual, for the Tertiary Piedmont Basin, Neogoniolithon-dominated coralline algae association is described and interpreted. This association is characterised by the common occurrence of freeliving thalli of Neogoniolithon raripunctatum and intergenicula of Subterraniphyllum thomasii. Finally, the paleoecological meaning of these species is discussed.

NEOGONIOLITHON CONTII COMB. NOV. BASED ON THE TAXONOMIC RE-ASSESSMENT OF MASTRORILLI’S ORIGINAL COLLECTIONS FROM THE OLIGOCENE OF NW ITALY (TERTIARY PIEDMONT BASIN)

Recent anatomic observations of the types of Lithophyllum contii Mastrorilli, 1967, Lithophyllum embergeri Mastrorilli, 1968, Mesophyllum flexile Mastrorilli, 1968 and Mesophyllum rigidum Mastrorilli, 1968 urged their revision under modern taxonomic schemes. Lithophyllum contii Mastrorilli, 1967 is transferred to the subfamily Mastophoroideae and the new combination Neogoniolithon contii is proposed. L. giammarinoi, L. embergeri, M. flexile and M. rigidum are considered to be younger heterotypic synonyms of L. contii , originally established on the basis of anatomical details herein considered to be artefacts due to improper orientation of studied thalli. Each species is critically analysed on the basis of original Mastrorilli’s collections (Genoa University, Dip.Te.Ris) and additional material collected at the type localities.

Biostratigraphic, paleobiogeographic and paleoecological implications in the taxonomic review of Corallinaceae

Some fossil species of nongeniculate coralline algae are synonyms of living species. These synonimies allow us to use stratigraphic distributions ofPhymatolithon calcareum (Pallas) Adey and McKibbin 1970 (Oligocene — Recent) and of the Mediterranean endemicsLithophyllum racemus (Lamarck) Foslie 1901 (Aquitanian — Recent) andLithothamnion valens Foslie 1909 (Priabonian — Recent) to clarify their paleobiogeography. It also illuminates the bionomy and paleoenvironments of benthic Mediterranean bottoms dominated by unattached corallines. The changes in species and morphologies in the coating sequence of rhodoliths, from nucleus to periphery, document sequential environmental changes.RiassuntoAlcune specie fossili di Corallinaceae non genicolate sono sinonimi di specie viventi. Queste sinonimie permettono di utilizzare la distribuzione stratigrafica diPhymatolithon calcareum (Pallas) Adey and McKibbin 1970 (Oligocene-Recente), come anche diLithophyllum racemus (Lamarck) Foslie 1901 (Aquitaniano-Recente) eLithothamnion valens Foslie 1909 (Priaboniano-Recente), due specie endemiche del Mediterraneo, per chiarirne l’evoluzione paleobiogeografica. Queste sinonimie tra specie fossili ed attuali e quindi il significato attribuibile ai fossili nell’ambito della bionomia bentonica mediterranea (almeno dal tardo Miocene) consentono di ricostruire con maggior dettaglio alcuni paleoambienti di fondo mobile dominati da queste corallinacee. In presenza di rodoliti multispecifiche, è possibile tracciare l’evoluzione del paleoambiente attraverso la sequenza di accrescimento delle rodoliti stesse.