COMMON AND RARE LOWER PLIOCENE AGGLUTINATED FORAMINIFERS OF PIEDMONT (NORTHWESTERN ITALY): DISTRIBUTION, TAXONOMY AND PALEOENVIRONMENT

To cite this article: Violanti D. (2023) - Common and rare Lower Pliocene agglutinated foraminifers of Piedmont (northwestern Italy): distribution, taxonomy and paleoenvironment. Riv. It. Paleontol. Strat. , 129(3): 411-455.


IntroductIon
This work analyzes the agglutinated foraminifers preserved in the Argille Azzurre (AA) and, for a lesser extent, in the Sabbie di Asti (SA) Formations, marine sediments deposited during the Early Pliocene on wide sectors of what is now the Pied-mont region (northwestern Italy). Agglutinated taxa represent the oldest foraminifers with a mineralized shell, known from the latest Precambrian (Vendian or Ediacarian) (Hemleben et al. 1990;Gaucher & Sprechmann 1999), widespread from the Early Cambrian to all the Phanerozoic (Culver 1991;Kaminski et al. 2008;Pawlowski et al. 2013). They are among the most widely distributed benthic protozoans, thriving in all the marine habitats, from brackish to abyssal depths (Hemleben et al. 1990). They are less or not sensitive to the calcitic dissolution that affects the calcareous forms at great depth (Berger 1972;Sliter et al. 1975), or under extreme conditions (Nardelli et al. 2022). Agglutinated foraminifers exploit different life strategies and microhabitats, with species thriving as infaunal or epifaunal (Murray 2006) and also able to exhibit an epibiotic or epilithic lifestyle (Waskowska & Kaminski 2019;Lintner et al. 2022).
Agglutinated species are considered a minor component of Northern Italy Pliocene foraminiferal assemblages, and generally they are represented by few long-ranging, calcareous-cemented taxa, such as Bigenerina nodosaria d 'Orbigny, 1826, Martinottiella communis (d'Orbigny, 1826, Textularia spp. Previous studies on Northern Italy Pliocene reported the agglutinated taxa only as a part of the total foraminiferal assemblage (Martinis 1954;Sampò et al. 1968; Violanti 2005, with references). Moreover, research specifically devoted to the study of this taxonomic group during Pliocene is very limited, mostly consisting of the old papers on the textularias by Fornasini (1883;1885;1887a, 1887b1887c;1887d;1887e;1888a;1888b;1902-1904a1902-1904b and more recently by Mancin (2001) and Mancin et al. (2012;. Few samples, collected in the central Piedmont and dated to the MPl3 foraminiferal zone (Cita 1975; Sprovieri 1992), differed from the exclusively calc-agglutinated assemblages by the occurrence of previously never recorded organic-cemented or ferruginous-cemented agglutinated species.
The studied area encompasses the northeastern Monferrato, the southeastern margins of the Turin Hill, the Astigiano, the Albese, and part of the Langhe (Fig. 1). At the present state of study, the Pliocene marine deposits of the central Piedmont are limited to the Zaclean MPl4a foraminiferal subzone or to a not better determinable MPl4 zone. Younger marine deposits, dated to the Piacenzian MPl5a subzone, based on the occurrence of Globorotalia bononiensis Dondi, 1963and/or Globorotalia aemiliana Colalongo & Sartoni, 1967, have been documented only out of the studied area, to the north on the western side of the Turin Hill (Tropeano et al. 2014;Gattiglio et al. 2015), along the northwestern side of the Monferrato at Casale Monferrato (Violanti & Sassone 2008), and to the east at Villalvernia (Pavia et al. 2022).
The sections of Moncucco Torinese, Isola d'Asti, Calliano, Incisa Scapaccino, and Revignano were selected as representative of the different agglutinated assemblages and the corresponding paleoenvironmental settings. The lowermost Pliocene succession (MPl1 and MPl2 zones) is documented in the lower part of the Moncucco section (Trenkwalder et al. 2008;Violanti et al. 2011b), and was recovered also in the Narzole borehole (Violanti et al. 2009). The interval encompassing the MPl3 zone and MPl4a subzone was more widely documented in the whole area. Very often assemblages from silty and sandy lithologies were devoid of planktonic biostratigraphic markers. As a consequence, they were dubiously referred to the Lower Pliocene on stratigraphycal basis or on the occurrence of benthic Lower Pliocene agglutinated foraminifers of Piedmont 413 species, such as Anomalinoides helicinus (Costa, 1857), Bolivina placentina Zanmatti, 1957, Uvigerina rutila Cushman & Todd, 1941, became extinct at the end of the Zanclean or during the earliest Piacentian (Sprovieri 1986).
Quantitative analyses performed in this study document a strong relation between the specific composition, diversity, and abundance of agglutinated foraminifers and paleoenvironmental setting. Therefore, agglutinated assemblages are suggested to be a useful tool to investigate the Early Pliocene (Zanclean) paleoenvironmental evolution of the Piedmont and northwestern Italy.

MaterIal and Method
145 samples were collected from natural or artificial sections and from small outcrops along roads or paths across fields and vineyards in the Asti district (PR = Primeglio, MN = Montechiaro, VS = Villa San Secondo, FR1-FR6 = Frinco, VG = Vaglierano, VI = Vigliano d'Asti, SM = S. Martino Alfieri), in the Cuneo district (GO = Govone S. Sebastiano, VE2-VE5 = Vezza d'Alba, MA = Monticello d'Alba), or from drillings for roadworks (CH90 from S272 drilling and CH83, S276 drilling, Cherasco) (Fig. 1). Sediments are gray clays and sandy silts of the AA, in some sites (Calliano, Incisa S. and Revignano) covered by gray to yellow sands and silty sands of the SA, both dated to the Zanclean (Early Pliocene), from the MPl1 to the MPl4 foraminiferal zones. The biostratigraphic scheme here followed is that of Cita (1975) emended Sprovieri (1992).
For the present study, quantitative data on the Moncucco T. and Isola d'Asti foraminiferal assemblages, presented in Trenkwalder et al. (2008) and Violanti (2012), respectively, were in part recalculated.
Data about the agglutinated taxa in the Moncucco T., Isola d'Asti and Calliano sections are here firstly published, with the exception of those concerning the Karreriella bradyi (Cushman, 1911) distribution, figured in Violanti et al. (2011b).
The quantitative study of the Incisa S. and Revignano sections as well as of samples from short outcrops and drillings was carried out for the present research.
For foraminiferal analysis about 200-500 g of dry sediment were disaggregated with water and a small amount of hydrogen peroxide (H 2 O 2 ). Then the material was gently washed, sieved into grain size fractions >250 μm, 125-250 μm and 125-63 μm, dried at 50° C and weighed.
Quantitative analyses were carried out on the total >125 µm fraction, split into aliquots containing approximately 300-400 well preserved foraminiferal tests, and observed under the stereomicroscope. Percentages of the identified planktonic and benthic species were calculated on the total of planktonic and benthic specimens, respectively. Percentages of the agglutinated species were calculated on the total benthic taxa. The 125-63 μm residues were not included in the counted fractions, owing to the scarcity or even absence of agglutinated tests.
For the present study, the P/(P+B-ST-SW) ratio was calculated following van der Zwaan et al. (1990) and van Hinsbergen et al. (2005), discarding from the total tests the benthic stress tolerant, opportunistic taxa (ST) (most of Bulimina and Bolivina species, all Brizalina, Fursenkoina, Globobulimina and most Uvigerina) and the infralittoral taxa (SW), transported from shallow depths (Ammonia, Elphidium, Lobatula, Neoconorbina, Rosalina). High numbers of ST and SW specimens affect the relative abundance of planktonic tests, and consequently the estimated paleobathymetry.
The diversity Shannon-Weaner H-Index was calculated using PAST ver. 1.77 (Hammer et al. 2008). The relative abundance of agglutinated (A) specimens on the total benthic (B) assemblage was expressed as the A/B ratio percentage. For each sample, the number of agglutinated genera (AGN) was counted. Percentage variations of the agglutinated species were analyzed. Agglutinated taxa were grouped in the morphological groups proposed by Jones & Charnock (1985), Nagy et al. (1995), Kaminski et al. (1995), Mancin (2001), Kaminski & Gradstein (2005) and Frontalini et al. (2014).
The studied material is housed at the Geology and Paleontology Museum of the Turin University under repository numbers MGPT-PU134019 to MGPT-PU134080.

GeoloGIcal settInG of the studIed sectIons
The Moncucco T. section (Figs. 1,2) represents the Pliocene portion of an upper Messinian to Pleistocene succession, extensively described by Trenkwalder et al. (2008). The Zanclean succession consists of about 26 m of bioturbated light gray marly clays. A slightly coarser layer, about 3 decimeters thick, occurred at 18.5 m from the base. Two biocalcarenitic beds, each one about 0.50 m thick, are interbedded in the upper part of the section.
The Isola d'Asti section (Figs. 1, 3) is located in the abandoned Merlino brickyard, about 1.5 km NE of Isola d'Asti village. About 24 m of predominantly bioturbated clays, pertaining to the AA, are exposed. Two beds of coarse sands, rich in mollusc shells and fragments, and separated each other's by a 0.2 m thick silty interval, occur between 6.5-7.2 m above the base of the section. Four laminated layers, few centimeters to few decimeters thick, are interbedded with the clays.
The Calliano section (Figs. 1, 4) was sampled in a disused quarry, NE of the Calliano village, along the SS (Strada Statale, National Road) 457. The succession is exposed for about 13 m and consists of a basal layer, about 1 m thick, of blue-gray homogeneous diatomitic clays, overlain by about 4.5 m of yellowish massive clayey silts, passing upward to about 7.5 m of poorly bedded sandy silts, only in part accessible for sampling.
The Incisa Scapaccino section (Figs. 1,5) was sampled at about 2 km NW from the center of the Incisa Scapaccino village, during and soon after the digging of the small artificial Valtiverno pond, in the Val Sarmassa Regional Reserve. The succession is about 48 m thick and starts, from the base, with about 4 m of biocalcarenites, now covered by the pond. The biocalcarenites are overlain by about 34 meters of discontinously exposed yellow to gray clayey silts to silty sands, often extensively bioturbated, interbedded with thin layers of thin to medium-grained sands. After a covered interval, about 5 meters of yellow sands, referable to the SA, are only partly exposed.
The Revignano section (Figs. 1, 6), located in the homonymous hamlet of the Vaglierano municipality, crops out for about 17 m along the Borbore stream, near the railway bridge of the Turin-Asti line. From the base, about 5-6 m of gray silty clays are exposed. Very abundant tubes of the polychaete Ditrupa arietina (O. F. Müller, 1776) are directly exposed on the ground. After a covered interval of about 2 meters, the silty clays are followed by about 3 m of gray-yellowish clayey silts, still very rich in Ditrupa tubes. The upper part of the succession is extensively covered by vegetation, and only about 3 m of yellow-reddish silty sands are exposed.

The agglutinated foraminiferal distribution in the selected sections
At the Moncucco T. section, a rich planktonic and predominantly calcareous benthic foraminiferal assemblage was collected from 52 samples of the AA at a mean sampling interval of 0.5 m. Biostratigraphic and paleoenvironmental interpretations proposed by Trenkwalder et al. (2008) indicate deposition from the basal Pliocene MPl1 zone (Sphaeroidinellopsis spp. acme-zone) to the MPl4a subzone (Globorotalia puncticulata interval-subzone). The P/(P+B-ST-SW) ratio (Fig. 2) is high to very high (60-80%) in the MPl1 and MPl2 zones. Upwards, from the coarse level at about 18.5 m from the base, it decreases to values ranging around 60% in almost all samples. The Shannon-Weaner H Index, calculated as a measure of the total benthic di-versity (calcareous plus agglutinated forms), varies from a minimum value of 1.36 (sample at 23.5 m from the base) to a maximum of 3.70 (sample 22.5 m) (Fig. 2). The abundance of agglutinated specimens (A) on the total benthic (B) foraminiferal assemblage is expressed by the A/B% curve (Fig.  2). Its percentages showed strong variations in adjacent samples, with a general increasing trend in the lowermost part of the Moncucco T. section, with values between 3.5-10.9, and a strong progressive decrease upwards, to values generally between 2-3. The AGN (Agglutinated Genera Number) (Fig. 2) showed low values (1-4) in the basal samples of the MPl1 zone, in which only Karreriella, Martinottiella, Sigmoilopsis, Siphotextularia or Textularia occurred. Then, in the MPl1-MPl2 interval, the values ranged between 3-7, with the progressive occurrence of Eggerella, Cylindroclavulina and Spiroplectinella. The AGN decreased (<4) in the uppermost layers, dated to the MPl4a subzone, in which the epibathyal taxa Eggerella and Cylindroclavulina are absent. As a whole, 14 agglutinated genera were recognized in the Moncucco T. section. 23 agglutinated species were collected from the total succession, but the number of species for each sample is generally very low, 1 to 5. The most common species are B. nodosaria, Cylindroclavulina rudis (Costa, 1855), Eggerella bradyi (Cushman, 1911), K. bradyi, M. communis and Sigmoilopsis schlumbergeri (Silvestri, 1904), which reach percentages greater than 2% in more than one sample (Fig. 2). Both the first occurrence of C. rudis and of E. bradyi are registered in the short interval characterized by the presence of mesopelagic Sphaerodinellopsis spp. (Trenkwalder et al. 2008). The group Textularia spp., including Sahulia conica (d 'Orbigny, 1839) and the genus Textularia, here represented by Textularia aciculata d 'Orbigny, 1826, Textularia agglutinans d'Orbigny, 1839, Textularia candeiana d'Orbigny, 1839, Textularia gramen d'Orbigny, 1846, Textularia pala Cžjžek, 1848and Textularia ponderosa Fornasini, 1887, was absent in many samples or present with values below 2%. Martinottiella perparva (Cushman, 1936) (Fig. 2) was recovered in the lower part of the section, with a maximum of 1.15% at 0.4 m from the base, and in the middle part up to 16 m from the base. On the contrary, Bannerella gibbosa (d 'Orbigny, 1826) and Spiroplectinella wrighti (Silvestri, 1903) were found in the upper half of the section, with percentages below 1% and 2%, respectively. Other rare agglutinated species were Cribrogoesella robusta (Brady, ues of 40-50% at the base of the section, increases to 80-98% in the samples correlated to the lower MPl3 zone and in the uppermost laminated layer, and ranges between 50-60% in the intervals among the laminites. The H Index (Fig. 3) displays values between 2-3.6 in most of the clays, and decreased to about 1 both in the sandy layers and in the laminites. The agglutinated foraminifers represent a low percentage of the total benthic assemblage in most samples from the clays, with a A/B ratio about 5% (Fig. 3), and are absent or very rare in the laminites and sands. Only in the interval between 5.0-6.7 m from the base, agglutinated tests are common and exceed 20% of the the total, ranging between 27.7-37.8%. The AGN (Fig. 3) was high in most of the lower part of the section, reaching a maximum of 10-11 genera in the samples above the sandy inter-1881), recovered in the sample at 9.7 m with 2.9%, Haplophragmoides canariensis (d 'Orbigny, 1839) in the sample at 24.20 m, with 0.31%, Karreriella gaudryinoides (Fornasini, 1885), found in the lower-middle samples, and Siphotextularia affinis (Fornasini, 1883), observed in very few samples along the whole section, both with percentages below 1%.
At Isola d'Asti (Figs. 1, 3) 42 samples were collected at intervals of 5-10 cm within the laminites, of 0.5-1 m in the massive, bioturbated clays. The lower part of the succession was dated by Violanti (2012) to the MPl3 zone, the upper section to the MPl4a subzone, due to the absence of Globorotalia margaritae Bolli & Bermudez, 1965 and the occurrence of Globorotalia puncticulata (Deshayes, 1832) and Globorotalia puncticulata padana Dondi & Papetti, 1968. The P/(P+B-ST-SW) ratio (Fig. 3) shows val- val. Upward, values range between 3-6, influenced by the disappearance of deep circalittoral/epibathyal genera such as Eggerella, Karreriella and Martinottiella. In total, 22 agglutinated species belonging to 14 genera were collected from the clays. The most common taxa, occurring with percentages greater than 2% almost in a single sample (Fig. 3), were Ammobaculites agglutinans (d 'Orbigny, 1846), B. nodosaria, M. communis, S. conica, S. schlumbergeri, S. affinis, S. wrighti, and Textularia spp., here represented by T. aciculata, T. agglutinans, T. gramen, T. ponderosa, Textularia sagittula Defrance, 1824, and Textularia soldanii Fornasini, 1883 In particular, A. agglutinans was collected from the lower-middle part of the section, and is common in the interval between 4.30-6.70 m from the base. Species occurring with percentages lower than 2% are B. gibbosa, and K. bradyi, whereas with values lower than 1% are E. bradyi, K. gaudryinoides, and M. perparva (Fig. 3). Cribrostomoides subglobosus subglobosus (Cushman, 1910), C. robusta, Psammolingulina papillosa (Neugeboren, 1856), and Psammosphaera fusca Schulze, 1875 were collected from the clays between 4.3-8.1 m from the base, all with values <1%. In the Calliano section, 9 samples (CL14 to CL22) were collected with an average sampling interval of about 1-2 m. The scattered occurrence of G. margaritae and G. puncticulata enable assigning the section to the MPl3 zone (Violanti et al. 2011a). The P/(P+B-ST-SW) ratio (Fig. 4) displays low values, ranging from a maximum of 23% in the basal diatomitic clay to about 11-19% in the clayey silts and to a minimum of 5.84% in the sandy silts. The H Index (Fig. 4) shows rather uniform values, around 3.5 in most samples, and ranges between a minimum of 2.94 in the basal sample to a maximum of 3.71 at 5.5 m from the base. The A/B ratio (Fig. 4) displays a minimum in the basal diatomitic clays (1.37%), it reaches its maximum of about 16% in the lower- most clayey silts and shows decreasing percentages upwards. The AGN (Fig. 4)  In the Incisa Scapaccino section 20 samples were collected at very variable intervals, ranging from 0.3-1 m up to 7 m, due to the thick coverage and low accessibility of the outcrop (Fig. 5). Foraminifers were absent in the basal mollusc-rich layer and in the overlying biocalcarenites, common but poorly diversified in the clayey silts, and scarce in the upper yellow sands. Tubes of the serpulid D. arietina are rather common in the uppermost clayey silts. The P/(P+B-ST-SW) values are very low, below or near 10%, in the lowermost and uppermost samples of the succession, and increase to 20-30% in most samples from the clayey silt (Fig. 5). The H Index values (Fig. 5) range between 2.69-2.15 in most samples, with a maximum of 3.31 in the yellow sands at 44.6 m and a minimum of 1.8 at 22 m from the base. The agglutinated foraminifers are frequent and the A/B ratio (Fig. 5) is between 15-30% in most of the clayey silts. A strong decrease to about 1-8% is registered in the interval between samples at 22.0-23.8 m, low values are also registered in the upper sands. The AGN (Fig. 5) ranges between 2-4, with a maximum of 5 genera at the top of the clayey silts, given by Bannerella, Bigenerina, Siphotextularia, Spiroplectammina, and Textularia. A total of 12 agglutinated species was recognized in the succession (Fig. 5). B. gibbosa, B. nodosaria and Textularia spp. are the most common taxa. T. aciculata is the more abundant species, and strongly dominates the Textularia spp. group, which includes also T. sagittula, T. agglutinans, T. candeiana, T. gramen, T. pala, and T. soldanii, all of them with percentages around or lower than 1%. Very rare (<1%) S. affinis and S wrighti were observed.
From the Revignano section, four samples were collected. The three samples from the clayey silts (Fig. 6) yielded very abundant tubes of the opportunistic serpulid D. arietina and foraminifers, the overlying sample from the sandy silts was barren. The P/(P+B-ST-SW) ratio shows uniform, extremely low values, below 2%. The H Index is between 1.72 and 2.36. Agglutinated specimens represent about 10% of the assemblages, and the A/B ratio ranges between 9.75-11.54%. Low values are registered for the AGN, ranging between 2-4. Only the genera Bannerella, Bigenerina, Sahulia and Textularia were found. Five agglutinated species were collected in the clayey silts: B. gibbosa, B. nodosaria, T. aciculata are rather common, whereas S. conica and T. angularis display values lower than 1%.

The agglutinated species distribution in the selected small oucrops
The eightheen samples collected from small natural or artificial outcrops, here quantitatively studied, were selected from many others for the occurrence of very rare calcarous-cemented and organicor ferruginous-cemented forms. Sediments consist of clayey or sandy silts, pertaining to the AA, deposited at depth between the circalittoral to the upper epibathyal zones (Dela Pierre et al. 2003;Ghielmi et al. 2019). Some samples yielded frequent to abundant planktonic foraminifers, dominated by Globigerina bulloides d 'Orbigny, 1826, Globigerinella obesa (Bolli, 1957, Globigerinoides obliquus Bolli, 1957, Globoturborotalita spp. G. margaritae and G. puncticulata were rather common and sometimes occurred together, allowing the correlation to the MPl3 zone (samples PR, GO, SM, VE3) (Fig. 7). In other samples, G. margaritae and G. puncticulata occurred separately or were missing. In the first case the zone was tentatively indicated, in the second case was not given.
The P/(P+B-ST-SW) ratio is greater than 50% in many samples, it reaches about 70-73% in the samples PR and VE3, respectively (Fig. 7). The lowest values, less of 20%, were observed in the FR1-FR6 samples. The diversity H Index showed values equal or greater then 3.5 in many samples, with a maximum of 4.4 in sample PR (Fig. 7). Samples from the Frinco area (FR1, FR3-FR6) differed in their less diversified benthic assemblages, reflected by the low values of the H Index, ranging from 2.8 to 3.2 (Fig.  7). The A/B ratio percentages (Fig. 7) show large variations, ranging from about 8% to about 26%. The AGN (Fig. 7) ranges from a minimum value of 6 to the maximum of 18 in sample VI, in which most of the rarest agglutinated forms were found. A total of 42 agglutinated species was recognized, but many of them occurred in few samples with percentages lower than 1%. Among the most common species (Fig. 7), B. gibbosa is present or frequent in all samples from the Monferrato area, absent or rare in the other samples. B. nodosaria occurs in almost all samples. On the contrary, C. rudis was only recovered in a few samples of the Albese. M. communis is more common in the Astigiano and Albese samples than in those from the Monferrato. S. schlumbergeri shows a rather similar pattern, with abundance often below 1%. Textularia spp., represented by S. conica, T. aciculata, T. angularis, T. agglutinans, T. candeiana, T. communis, T. gramen, T. pala, T. ponderosa T. soldanii, is often common to abundant (Fig. 7). E. bradyi, K. bradyi, K. gaudrinoides, M. perparva, S. affinis, and S. wrighti randomly occur with percentage below or near 1%. Rare specimens of A. agglutinans, Ammoscalaria pseudospiralis (Williamson, 1858), Ammoscalaria runiana (Heron-Allen & Earland, 1916), Ammoscalaria tenuimargo (Brady, 1884), Bigenerina compressissima Colom, 1946, C. robusta, C. subglobosus subglobosus, Crithionina pisum Goës, 1896, C. cancellata, H. canariensis, Lagenammina atlantica (Cushman, 1944 (Cushman, 1911), and Spirotextularia fistulosa (Brady, 1884) were counted in the >125 μm fraction (Fig.  8). Among the very rare species, only A. agglutinans, C. cancellata and P. papillosa are rather common and reach abundances between 2 and 4%.

Morphogroup analysis
In order to improve the paleoenvironmental interpretation of the Piedmont Pliocene succession, the recognized agglutinated species were combined into morphological groups. The morphogroup analysis of agglutinated foraminifers, based on the relation among the test morphology, life position and trophic habits, proposed by Jones & Charnock (1985), was subsequently modified and successfully applied to fossil and recent assemblages (Nagy et al. 1995;Kaminski et al. 1995;Violanti 2000;Mancin 2001;Kaminski & Gradstein 2005;Kaminski et al. 2011;Frontalini et al. 2014;Setoyama et al. 2018). In the studied assemblages four broad morphogroups were distinguished (Tab. 1).
Morphogroup A comprises the tubular or branching shapes, thriving as epifaunal, mainly suspension feeders and is here insignificant, being represented by very rare fragments of R. cf. abyssorum, recovered only in sample VI (Fig. 10).
Morphogroup B includes epifaunal to shallow infaunal taxa of globular shape such as C. pisum, L. atlantica, Psammosphaera spp., the rounded planispiral and trochospiral forms C. subglobosus subglobosus, C. cancellata, H. canariensis, Recurvoides sp. and the elongate keeled with mixed coiling modes S. milletti and Spiroplectinella spp., included as epifaunal following Kaminski & Gradstein (2005). The morphogroup B is scarce in the studied sections, given almost exclusively by the elongate keeled S. wrighti (Fig. 9). Only in samples FR3-FR5, GO, SM, VI, VE3, CH90, and CH83, morphogroup B is rather more represented. Violanti D. 420 The morphogroup C is strongly dominant and constitues the total agglutinated assemblage in most of the studied samples. It comprises the common calc-agglutinated, infaunal forms with elongat-ed tapered or subcylindrical shape B. nodosaria, E. bradyi, K. bradyi, M. communis, and Textularia spp. The ovoidal B. gibbosa and the stout subcylindrical C. rudis were included in this morphogroup.
The milioline shaped morphotype is given by S. schlumbergeri, correlated to the morphogroup C both for its flattened-tapered shape and for its inferred infaunal microhabitat (Violanti 2000;). It shows low percentages in the fine sediments, whereas it is absent or insignificant in the inner shelf silty sands and sands. Morphogroup D, including the flattened trochospiral and planispiral epiphytal forms, is totally absent.

dIscussIon
Quantitative analyses of agglutinated foraminifers were carried out on the sections and small outcrops previously described and selected for their good documentation of the Pliocene succession in the Piedmont, both from the biostratigraphic and the paleoenvironmental point of view. The agglutinated taxa distribution and inferred paleoenvironmental significance will be discussed following the stratigraphic sequence. Parameters concerning the total foraminiferal assemblages such as the P/ (P+B-ST-SW) ratio %, the Diversity H Index, the A/B % and the AGN provide the framework to investigate the paleoenvironmental requirement of the agglutinated species.
Calcareous-cemented species distribution K. bradyi, M. communis, S. schlumbergeri and rare Textularia spp. are the only agglutinated taxa found at the base of the Pliocene (Fig. 2), among the benthic re-immigrants the Mediterranean Sea after the Messinian Salinity Crisis. They occur in assemblages K. bradyi was collected with low percentages in almost all the MPl1 and MPl2 samples and in some of the MPl3 assemblages. This deep circalittoral to epibathyal species (Wright 1978;Murray 2006) is seldom reported in other Pliocene rather deep assemblages of Piedmont (Martinis 1954).
M. communis also occurs in most of the assemblages dated to the MPl1-MPl3 zones (Figs. 2, 3), it is rather common in few small outcrops (Fig. 7), with rather high P/(P+B-ST-SW) ratios and well diversified deep circalittoral/upper epibathyal assemblages. As K. bradyi, it is absent in the younger and shallower shelf assemblages of the clayey and sandy silts widespread in the region.
The small M. perparva was found in samples dated to the MPl1 zone and in other few deep assemblages of the MPl3 and MPl4a zones (Figs. 2,3,8). The taxon, extinct during the MPl5 zone at about 2.4 My (Sprovieri 1986), in the Pliocene Piedmont succession is rare and sporadic, restricted to the deepest assemblages of the area, from marly clays with high to very high P/(P+B-ST-SW) values (60-80%), and rather low A/B%. Rare specimens of the taxon were seldom recorded in Pliocene sediments of the Mediterranean area (Sprovieri 1986;Barra et al. 1998). Therefore, the extinct M. perparva seems to have been preferential of deep epibathyal or mesobathyal depths and its distribution appears more restricted than that of M. communis, for probably a more selective ecological requirement.
S. schlumbergeri is the only porcellanaceous species recovered in most of the studied samples, here included in the agglutinated group because of its agglutinated outer coating (Fontanier et al. 2003;Mancin et al. 2015). Only at the base of the Moncucco T. section, MPl1 zone, S. schlumbergeri reached a percentage about 5%. It was discontinously found with abundances less than 3% in the marly clays, clays and clayey silts dated to the MPl2 to MPl3 zones (Figs. 2, 3, 4, 7). S. schlumbergeri, a shallow infaunal form (Jorissen & Wittling 1999), positively correlates with high organic matter (Jorissen 1987). The low abundance of S. schlumbergeri in the Piedmont, in comparison with those registered in high productivity areas, suggests a rather low availability of food and low surface productivity in the area during most of the Pliocene.
The bathyal E. bradyi and C. rudis, absent at the base of the Pliocene, occur in the epibathyal assemblages slightly later during the MPl1 zone ( Fig.  2) and up to the MPl3 zone (C. rudis) or to the MP-l4a subzone (E. bradyi) with low abundances, <3% and <4%, respectively (Fig. 2). These species re-entered the Mediterranean basin following the influx of the deep-marine calcareous benthic taxa such as Cibicidoides kullenbergi (Parker, 1953), Cibicidoides robertsonianus (Brady, 1881), and Siphonina reticulata (Cžjžek, 1848) (Sgarrella et al. 1997), and contributed to the increased benthic diversity and abundance C. rudis is recorded from bathyal settings (Sprovieri 1986;Violanti 1987;. It predominantly selected biogenic grains, most of them foraminiferal fragments or tests, embedded in abundant calcareous cement. Fragments of planktonic foraminifers are abundant on the test surface, and appear to be preferentially picked. Therefore, the distribution of C. rudis seems directly related to a sea-floor rich in biogenic debris and abundant planktonic tests. E. bradyi, as C. rudis, is absent at the base of the Pliocene and occurs slightly later during the MPl1 zone (Fig. 2). Its delayed occurrence as well as its early disappearance in comparison with that of K. bradyi agree with data of Phleger et al. (1953) and indicate a deeper paleobathymetrical settings for E. bradyi than K. bradyi.
In comparison with the previous species, B. nodosaria was found later in the MPl1 zone, in assemblages with slightly decreasing P/(P+B-ST-SW) ratios (Fig. 2). The cosmopolitan B. nodosaria is one of the most common agglutinated foraminifers in the studied succession, even if in general with low percentages. The species is reported as a shelf taxon (Blanc-Vernet 1969; Milker & Schmiedl 2012), but was also reported from open-sea, bathyal recent and fossil assemblages Frontalini et al. 2014;Symphonia & Senthil 2019). Living specimens of the shallow to intermediate infaunal B. nodosaria were reported from mesotrophic upper slope stations (Contreras-Rosales et al. 2012). These data support the hypothesis that in the Piedmont Pliocene epibathyal settings B. nodosaria is authochthonous, and not displaced from shallower depths.
Rare Textularia spp. are documented from the basal Pliocene (Fig. 2), and are very rare or absent in the deep circalittoral/epibathyal assemblages of the region, with high or middle P/(P+B-ST-SW) ratios and low A/B percentages (Figs. 3,7,9). High frequence and diversity of Textularia spp. are registered in the silty clays, clayey silts and sandy silts (Figs. 4,5,6), as part of assemblages with low to very low P/(P+B-ST-SW) %, common calcareous benthic forms, typical of muddy infralittoral to circalittoral depths such as Brizalina spp., Bulimina spp., Cassidulina carinata Silvestri, 1896, Nonion boueanum (d'Orbigny, 1846 (Murray 2006). T. aciculata is the dominant species of the group in silty clays or clayey silts rich in D. arietina, an opportunistic suspension-feeding polychaete, typical of shallow circalittoral environments, periodically disturbed by episodes of instability (Peres & Picard 1964;Hartley 2014). T. aciculata is common to frequent in the clayey to sandy silts cropping out in the neighbourhood of Asti, overlaying the AA or heteropic between the AA and the SA. These silts show lithologies and fossil assemblages with intermediate characteristics between those of the previous two formations and can be interpreted as circalittoral prodelta deposits, characterized by large amount of clayey-silty sediments, abundant organic matter and moderate dysaerobic conditions. T. aciculata is reported from many Pliocene and Pleistocene marine delta successions Di Bella et al. 2002) and from Po Plain Quaternary and Recent sediments Fiorini 2004). On the basis of this distribution, T. aciculata seems to be a rather shallow taxon, preferential of siltysandy sediments, subjected to periodical supply of mud, and well suited to unstable conditions, such as those influenced by river inflows. Its increasing abundance in the area around the Asti town could be related to the tectonic and regressive phase active during the late Zanclean (Ghielmi et al. 2019), that led to the infilling of the area by prograding and interfingering delta river fronts.
B. gibbosa (Figs. 4, 5, 6) shows a distribution similar to that of T. aciculata, and is frequently recorded in the clayey silts and sandy silts dated to MPl3-MPl4 zones (Martinis 1954;Ghielmi et al. 2019). The taxon is absent in the older bathyal assemblages and rare in the infralittoral sands of the Astian facies (Sampò et al. 1968) and appears to be typical of deep infralittoral and shallow circalittoral depths.

Organic-and ferruginous-cemented species distribution
Specimens of the organic-or ferruginous-cemented taxa found in the Piedmont Pliocene assemblages, such as Ammoscalaria spp., C. pisum, C. cancellata, H. canariensis, L. atlantica, P. papillosa, Psammosphaera spp., Recurvoides sp., R. cf. abyssorum and R. scorpiurus, are very fragile, easily broken during the study procedures. Therefore, reworking was excluded for their poor preservation potential. For some species, transport or displacement cannot be excluded, suggested by the common broken chambers of A. agglutinans, C. cancellata and Recurvoides sp. Frequencies of the single taxa are often very low and could be considered as negligible or casual. But the co-occurrence of some or several organic-or ferruginous-cemented taxa in the same sample, as well as their finding in a rather restricted geographic area of the central Piedmont, in a time-interval pertaining to the MPl3 zone, appear significant of peculiar paleoenvironmental conditions. Sediments yielding these rare forms were sampled at south of Asti, from the hills bordering the Tanaro river valley, and from a northern sector in the Monferrato, south of the Moncalvo town (Fig. 1B). The latter localities are at the southern margin of the "Pliocene Moncalvo gulf " (Sacco 1889), and near to the La Torretta and Calliano outcrops of diatomaceous silts and clays, interpreted as evidences of seasonal rather high productivity episodes during the Zanclean (Violanti et al. 2011a). In the Astigiano, like the other agglutinated taxa, they are absent in the laminated layers, deposited during episodes of sea-floor dysoxia. Therefore, well oxygenated sediments seem to be required for the diffusion of the organic-cemented agglutinated foraminifers.
Data on living assemblages report common to frequent A. agglutinans, C. subglobosus, Psammosphaera spp. and R. scorpiurus in mesotrophic environments (Fontanier et al. 2005). A. pseudospiralis, H. canariensis, L. atlantica, P. fusca, R. cf. abyssorum, R. scorpiurus, together with B. nodosaria and T. sagittula, were reported in rather shallow recent assemblages along the coasts of Turkey, in areas influenced by currents or by deep sea waters (Meriç et al. 2014). All these data document a strong relation among these agglutinated taxa, trophic environment and water circulation, which could explain their finding in the studied sites.
Tests of organic or ferruginous-cemented taxa here recovered could be the "survivors", fortuitously preserved as part of a more abundant non-fossilising foraminiferal fauna. The occurrence of many fragile species during the MPl3 zone, in sediments deposited on the outer shelf or upper slope, and in assemblages indicating a good seafloor oxygenation, suggests enhanced circulation and nearly mesotrophic conditions in part of the Asti basin and Monferrato during this time interval. Increasing tectonic activity, leading to the Intra-Zanclean deformation phase and the regressive phase (Ghielmi et al. 2019) as well as seasonality can be at the origin of local condition of strong currents and water mixing, similar to those now present along canyon or straits slopes and margins (Fontanier et al. 2005;Frontalini et al. 2014).

Morphogroup distribution
The morphogroup methodology was applied for a broad comparison of agglutinated foraminiferal assemblages and paleoenvironments.
The presence of morphogroup A is interpreted as an indicator of a contour current or deeper food-carrying bottom currents (Kaminski et al., 1989;). Despite the low abundance, the presence of the organic-or ferruginous-cemented taxa, included in the morphogroups A (R. cf. abyssorum) and B (C. pisum, L. atlantica, Psammosphaera spp., C. subglobosus subglobosus, C. cancellata and H. canariensis) is here interpreted as an evidence of counter currents active in the central Piedmont area during the Zanclean MPl3 zone. The strong dominance of the morphogroup C was interpreted by Jones & Charnock (1985), Kuhnt et al. (1996), Kaminski et al. (1999), Mancin (2001), and  as typical of assemblages from the continental shelf to the upper continental slope, such as those documented in the studied area.
The absence of morphogroup D, including the epiphytal but also interstitial (Jones & Charnock 1985;Violanti 2000) trochamminids, was also observed in the older Epiligurian succession (Mancin 2001) and could be a result of taphonomic processes.

conclusIons
The general assemblages composition confirms the dominance, or the exclusive presence, of calc-agglutinated infaunal species of elongated tapered or subcylindrical shape, included in the Morphogroup C, and shows significant variations in specific diversity and abundance, strictly related to different paleoenvironmental settings.
The re-flooding of the Mediterranean basin after the MSC and the re-entry from the Atlantic Ocean of foraminifers are evidenced also by agglutinated taxa in the lowermost Pliocene layers, characterized by less diversified assemblages with K. bradyi, Martinottiella spp., S. schlumbergeri and rare Textularia spp. The progressive rise of the sea level, registered in the Mediterranean basin during the MPl1 zone and documented by the influx of deep water calcareous benthic species such as C. robertsonianus, S. reticulata, and of abundant planktonic taxa, among them the mesopelagic Sphaeroidinellopsis spp., is also registered by the occurrence of C. rudis, C. robusta and E. bradyi. The low frequence of these bathyal species, and the common occurrence of the deep circalittoral to epibathyal B. nodosaria and M. communis, suggest upper slope depths and open marine conditions during the earliest Pliocene, MPl1 and MPl2 zones, in the central part of the basin. The small, very rare, deep agglutinated M. perparva is the first to disappear from the counted fractions. It seems one of the most sensitive agglutinated taxa to the paleonvironmental changes occurring in the area during the Zanclean. From the MPl3 zone upward, the deepest agglutinated species C. rudis, E. bradyi, K. bradyi, and M. communis become progressively rarer or disappear, indicating a reduction in bathymetry and width of the Pliocene marine basin. Diatomitic clays, related to rather high, probably seasonal, productivity episodes, crop out at Calliano and in the nearby Monferrato area. In this time interval, dysaerobic sea-floor conditions are documented by laminated layers at Isola d'Asti. The organic or ferruginous-cemented taxa were found only in sediments deposited after the diatomitic clays or before the laminated layers, suggesting normal or good oxygenation. Among the total of 42 agglutinated species identified in the Lower Pliocene succession of the central Piedmont, many of them were very seldom found, such as C. cancellata, R. scorpiurus and R. cf. abyssorum, or were never reported, such as A. agglutinans, Ammoscalaria spp., B. compressissima, C. subglobosus subglobosus, C. pisum, H. canariensis, L. atlantica, Psammosphaera spp., P. papillosa, S. milletti, and S. fistulosa.
The occurrence of the rare organic-cemented taxa in the central part of the Piedmont basin is here suggested as the only signal of not otherwise registered paleoenvironmental conditions, such as a locally active deep circulation, a rather mesotrophic bottom waters, a complex sea-floor paleomorphology, and seasonality, all influenced by the increasing tectonity activity and by harbingers of the Late Pliocene climatic deterioration.
In the shallower and younger sediments of the MPl4a subzone, agglutinated foraminifers are frequent but poorly diversified. The highest abundance of Textularia spp., dominated by T. aciculata, and of B. gibbosa is recorded in shallow circalittoral unstable muddy layers, widespread in the Astigiano area, and interpreted as prograding and interfingering fan-delta sediments. T. aciculata is suggested as a typical agglutinated species of shallow marine deposits and, when common to frequent, indicative of a deltaic paleoenvironment.
Remarks. This cosmopolitan species is reported from Late Cretaceous to Recent circalittoral to abyssal depths (Kaminski & Kuhnt 1991;Kaminski & Gradstein 2005;Stefanoudis et al. 2016), and interpreted as an epifaunal/shallow infaunal form (Kuhnt et al. 2000).  found rare specimens in the infralittoral zone of the Gulf of Policastro (Tyrrhenian Sea), only near rivers mouths. It occurs also in recent assemblages from brackish to shallow marine sediments of the Northern Adriatic ) as well along the Aegean coasts (Frontalini et al. 2014). Kaminski & Kuhnt (1991) related its variations in size and test morphology to the bathymetry and noted an increase in the number of uniserial chambers in the abyssal forms, in comparison with shelf and bathyal ones.
In the studied Pliocene assemblages, this taxon was found in samples referred to the MPl3 foraminiferal zone and to circalittoral or upper epibathyal depths. Many specimens were broken or showed a very short uniserial stage, suggesting transport and a rather shallow paleoenvironment.
Test elongate, compressed, planispiral in the early stage, then uniserial. Planispiral portion involute, with 1-1.5 whorls, uniserial portion formed by 3-6 nearly rectangular chambers. Sutures very slightly depressed. Aperture terminal, at the end of a neck more or less produced. Wall coarsely agglutinated, imperforate, with organic cement.
Remarks. This cosmopolitan taxon occurs in a wide depth and latitude range (Chapman & Parr 1937;Murray 2006), from more or less sandy deposits between 20 and 50 m in the Gullmar Fjord (Höglund 1947), rare in shallow fjord and shelf and common in deep shelf assemblages ). In the Mediterranean area it was reported from recent biogenic, detritic sediments of submerged banks (Moncharmont Zei 1962), from muddy shelf (Blanc-Vernet 1969), and upper slope sediments (Sgarrella & Moncharmont Zei 1993;Meriç et al. 2014). It was interpreted as a shallow infaunal form (Barmawidjaja et al. 1992).
In the studied material, rare A. pseudospiralis occurs in silty or sandy clays from the Asti area dated to the MPl3 zone and in samples PR and FR6 from the Monferrato. Test compressed, planispirally coiled, involute, with a terminal uncoiled part. Test with 4-8 chambers in the last whorl, with a subrectangular last uncoiled chamber. Sutures indistinct. Aperture terminal, irregular. Wall coarsely agglutinated, imperforate, with organic cement.
Remarks. The taxon, described by Heron-Allen & Earland (1916), is characterized by a very short uniserial portion, a less compressed text with more abundant cement in comparison to A. pseudospiralis and A. tenuimargo. It is a shallow water, intertidal-subtidal brackish taxon common in fine to medium sand with <20% mud and low TOC and salinity (Alve & Murray 1999; Murray & Alve 2011).
Rare specimens confidently attributable to this taxon were collected in the circalittoral to upper epibathyal assemblages of samples VI and SM, dated to the MPl3 Zone.
Remarks. The taxon is cosmopolitan, reported from bathyal depths in the Atlantic (Cushman 1920), it was also found living at depths ranging from 250 to 2668 m (Murray 2006), between 200 and 700 m in the Skagerak (Höglund 1947), occasionally common in shelf deep bottoms . Boltovskoy et al. (1980) included A. pseuspiralis and A. tenuimargo, such as the whole genus Ammoscalaria, among the hypoaline forms of the southern Brazil and the Rio de la Plata. In the Mediterranean Sea, rare specimens have been documented from sandy pelitic and pelitic infralittoral and circalittoral sediments of the Gulf of Policastro and the Gulf of Salerno , between 25 and 445 m in the Gulf of Naples (Sgarrella & Moncharmont Zei 1993).
Specimens here determined as A. cf. tenuimargo differ from those described by Brady (1884) for a reduced number of chambers and a stouter test. The last chamber, larger than the previous ones and the internal structure, observed in transmitted light, agrees with the characters of the taxon as described by Höglund (1947).
It was found in the samples PR, SM and MA, with percentages <1%.
Remarks. The B. gibbosa stratigraphic range is controversial: it is reported from the Oligocene to the Recent by Salvatorini (1968), from the lowermost Pliocene to the Quaternary by Agip (1982). It is also accepted as living by WoRMS (2023). Commonly reported in Pliocene shelf assemblages of the Mediterranean area (Martinis 1954; Sampò et al.

Bigenerina compressissima
Remarks. The species was originally described from the Miocene of Mallorca (Colom 1946). Very rare, well preserved specimens were described in the Lower Pliocene (MPl3 Zone) assemblages of the Rio Torsero (Ligury, Northwestern Italy) (Violanti 1987).
In the studied area B. compressissima was found in sample PR, dated to the MPl3 zone.
The species occurs in most of the studied samples. It reaches its highest frequencies in AA silts and sandy silts referred to the circalittoral zone. It is very rare or absent in the infralittoral Asti Sands.
Remarks. Cushman (1935) erected the genus Cribrogoesella, indicating as genotype Bigenerina robusta Brady, 1881, illustrated by Brady (1884). The species is reported in the Atlantic from Miocene to Holocene (Loeblich & Tappan 1987). It is very seldom recorded in the Mediterranean area from the Lower Pliocene to about the Middle Pleistocene assemblages (Sampò et al. 1968;Agip 1982;Rasmussen & Thomsen 2005). Blanc-Vernet (1969) reports rare C. robusta from Recent and Pleistocene bathyal Mediterranean muds. It was common in the recent Coral Rubble Facies of Santa Maria di Leuca deep-water coral province (Ionian Sea) (Rosso et al. 2010).
In the studied material C. robusta very seldom occurs, in sample 9.70 m at Moncucco T., and in samples MN and CH83.
Test stout, subglobular, involute, initial stage streptospiral, later almost planispiral, 4-6 chambers in the last whorl, gradually increasing in size. Sutures slightly depressed or flush with the surface, Aperture a broad, low slit at the base of the apertural face, bordered by a lip. Multiple openings may occur in larger specimens. Wall thick, finely agglutinated, surface rather smooth, with organic cement, imperforate.
In the studied material very rare specimens occur in the Isola d'Asti section, in samples FR3, FR5 and VI.
Remarks. A very rare and seldom reported species, found at about 164 m in the Timor Sea (Loeblich & Tappan 1994) and in deeper stations, exceeding 200 m in depth (Höglund 1947) down to about 3,000 m (Flint 1899). Recorded as living in Antarctic waters (Violanti 1996;2000).
In the studied material, it was found in sample VI. Test large, planispiral, involute, biconvex. Perypheral margin rounded to subacute. Umbilical area depressed. Chambers numerous, about 9-12 in the last whorl, gradually increasing in size. Sutures slightly depressed, curved to sigmoid. Wall finely agglutinated, often containing coarse mineral grains, with an inner alveolar layer and an outer imperforate thin layer. Organic cement, imperforate.
Remarks. A cosmopolitan species, known from the Late Eocene to Recent, reported as bathyal to abyssal (Hermelin 1989;Kaminski & Gradstein 2005;Kaminski et al. 2008). In the recent assemblages of the Mediterranean Sea it was known from bathyal muds (Blanc-Vernet 1969), from 500 m depth downward (Colom 1974), rare in the deep-water coral province of Santa Maria di Leuca (Rosso et al. 2010). In the Gulf of Naples it was found in a depth range of 250-410 m (Scorziello 1979). Martinis (1954) reported rare Cyclammina sp. from the Pliocene sandy clays of Piedmont.
In the studied material, C. cancellata was recognized in samples from the Astigiano and Monferrato areas, dated to the MPl3 zone or of undetermined Pliocene age.
Cylindroclavulina rudis (Costa, 1855) Pl Test very large, stout, subcylidrical in the adult specimens, globular in the juveniles. Early stage indistinctly triserial, followed by a short biserial stage and by a longer uniserial stage with 3-4 low chambers. Sutures indistinct, aperture a narrow slit produced on a thin, short neck. Wall thick, agglutinating biogenic debris (bryozoans, molluscs, small plank-tonic and benthic foraminiferal tests), arranged to give a slightly rough outer surface. Inner surface smooth. Abundant calcareous cement.
It occurs with abundances near 2% in the upper MPl1 and MPl2 zones samples of the Moncucco section and in sample VE5.
Remarks. A cosmopolitan living species, known from the Oligocene (Agip 1982), reported as deep infaunal (Kuhnt et al. 2000). It is very seldom reported from deep-water Pliocene assemblages (Martinis 1954). Wright (1978) and  pointed out the easy confusion with Karreriella bradyi immature specimens and the possibility that these two species might be often lumped together.
In the studied area, E. bradyi specimens are rare, reaching abundances of about 2-4% only in the epibathyal clays from part of the MPl1 and MPl2 zones, absent in shelf deposits.
Very rare specimens were found in samples FR1, VE2 and MA.
Remarks. It is a cosmopolitan living species, know from the middle Eocene (Agip 1982), rather commonly reported as rare from recent and Pleistocene marine sediments (Brady 1884;Herb 1971;Murray 1971;2006;Mancin et al. 2015) as well as from Pliocene deep circalittoral and bathyal assemblages (Martinis 1954;D'Onofrio 1981;Jonkers 1984;Barra et al. 1998;Rasmussen 2005). In the Mediterranean bathyal deposits, it is frequently associated with the triserial Eggerella bradyi (Wright 1978;. Phleger et al. (1953) report a shallower upper depth limit for K. bradyi (about 155 m) than that of E. bradyi (about 600 m) in the North Atlantic. Also in the Piedmont assemblages, K. bradyi showed a rather different dis-tribution than E. bradyi, suggesting a shallower bathymetrical range for the first taxon.
In the studied area, K. bradyi occurs in the MPl1 and MPl2 zones epibathyal assemblages. It is scarce in the deep circalittoral/upper epibathyal assemblages of the MPl3 zone.
In the studied material it occurs in few samples from the lower-middle part of the Moncucco and Isola d'Asti sections, in samples VG, VI, SM and CH90, with percentages below 1%.

Fig. 1 -Lagenammina atlantica
Remarks. The cosmopolitan species was known from the lower Eocene (Agip 1982), frequently reported from Mediterranean Miocene and Pliocene assemblages (Ferasin 1954;Martinis 1954;Jonkers 1984;Rio et al. 1988). It is common to abundant in the modern deep sea from high latitudes (Chapman & Parr 1937;Herb 1971), and in the upper Quaternary bathyal sediments of the SW Pacific (Mancin et al. 2015).

Martinottiella perparva
Remarks. In the Mediterranean area, the species is generally rare and seldom reported in deep assemblages from the Langhian to the Pliocene (Agip 1982;, up to the MPl5 zone (Sprovieri 1986).
The species was recovered in the AA epibathyal assemblages of the Moncucco T. section and of the Narzole borehole (Violanti et al. 2009), referred to the MPl1 and MPl2 biozones, and in one samples from the Isola d'Asti section, MPl4a subzone.
Rare specimens were found in the lower part of the Isola d'Asti and Calliano sections, in samples PR, FR3, GO, VI, VE5 and CH83.
Remarks. The taxon differs from P. fusca for its small diameter and the smaller, more uniform clasts included in the wall. Flint (1899, p. 268) described the species with "test often built around a long sponge spicule, which tranfixes the test". The very rare Piedmont specimens, collected from samples MN, VI and CH90, do not yield the sponge spicule, described as often present, (therefore not always), but for the other characteristics, such as the small test, and uniform clasts dimensions seem to correspond to the Flint's species.

Recurvoides sp.
Pl. 6, fig. 3 Test large, trochospirally enrolled, plano-convex, with 4-4.5 chambers in the last whorl. The last chamber increases in dimensions more rapidly than the previous ones. The umbilicus is moderately depressed. Sutures straight and very slightly depressed. Wall thick, with abundant coarse mineral grains and less frequent smaller grains, loosely cemented. Cement organic. Aperture not evident, infilled by sediment.
Remarks. Very rare specimens and fragments, here tentatively assigned to the genus Re-curvoides, occur in samples FR3, FR5, GO, VI and CH83.
Test elongated, with 4-6 subglobular to subcylindrical chambers, uniserially arranged along a straight or sligtly curved axis. Wall coarsely agglutinated, with poorly sorted terrigenous grains. Cement organic. Aperture terminal, rounded, at the end of a short neck.
In the Piedmont Pliocene it was recorded by Sampò et al. (1968) in the "Astian" assemblages around Asti. Very rare specimens were found in samples FR3, VG and CH90.
Rare fragments of Rhabdammina sp. were reported in Piedmont Pliocene "Astian" assemblages by Sampò et al. (1968). Rare tubular fragments were found in sample VI.
Test short, small, biserial throughout, with few pairs (4-5) of subtriangular chambers, wider than high, rapidly increasing in size. Sutures straight or fairly curved, sligthly depressed. Wall coarse to medium size grained with calcareous cement, canaliculate. Aperture a low arch at the inner margin of the last chamber.
Remarks. A very frequently recorded taxon, but probably, as observed by Lacroix (1932), many reports had included under this name juvenile specimens of other textulariids. In the Mediterranean, it occurs in the infralittoral and circalittoral zones (Koukousioura et al. 2011), down to 671 meters in the Eastern Mediterranean (Parker 1958), and from 15 to about 300 m (Frontalini et al. 2014) in the Aegean Sea. Also reported from Pliocene and Pleistocene assemblages of the Mediterranean area Di Bella et al. 2002).
In the Piedmont succession, it is rather common in the lower part of the Isola d'Asti clays, very rare in the silty-sandy sediments.
Remarks. A living cosmopolitan species, in the Mediterranean Sea sediments reported from the upper Miocene to Quaternary (Agip 1982) and from a depth-range of about 30-1000 m (Sgarrella & Moncharmont Zei 1993;Alfirević 1998).
In the Piedmont succession, it occurs with low percentages in the circalittoral/upper epibathy-al clays and marly clays dated to the MPl1-MPl4a zones.
Remarks. The stratigraphic range of this taxon is known from the Tortonian to the Quaternary (Salvatorini 1968). It is reported from Pliocene circalittoral and upper epibathyal assemblages (D'Onofrio 1981;Jonkers 1984;Violanti 1987) of the Mediterranean area.
In the studied material S. affinis is rather common in the lower clays of the Isola d'Asti section (MPl3 zone).
Siphotextularia sp.1 Pl. 7, Very rare specimens, recovered only in the PR (Primeglio) and MN (Montechiaro) samples, were ascribed to this form. They differ from S. affinis from their very large and stout tubular neck, and a rather more subangular chambers. They could be a different species as well as an aberrant form of S. affinis. (Cushman, 1911) Pl. 7, figs. 8-10 1911Textularia milletti Cushman, p. 133, figs. 18-19. 1932Spiroplectammina milletti -Cushman, p. 7, pl. 1, figs. 5a,b. 1987Textularia milletti -Loeblich & Tappan, p. 173, pl. 192, figs. 17-19. 1994 Test of medium to small size, stout, compressed. Planispirally coiled juvenile chambers, well developed in the megalospheric forms. Adult chambers biserially arranged, rapidly increasing in width, larger than high, with thick, rough upper margins and depressed lower margins. Peripheral margin acute. Sutures often indistinct. Wall coarsely agglutinated, including dominant inorganic fragments and few biogenic debris, with calcareous cement. Parapores evident on the outer surface. Aperture a narrow arch at the inner margin of the last chamber.
Remarks. Frequently reported in the Mediterranean area from circalittoral to upper epibathyal Tortonian to Recent assemblages (Martinis 1954;Sampò et al. 1968;D'Onofrio 1981;Agip 1982;Rio et al. 1988;Coppa et al. 2001;Frontalini et al. 2014), but, as observed by Sgarrella & Moncharmont Zei (1993), frequently confused with Textularia sagittula. This latter taxon, on the basis of the original description, differs from S. wrighti for the lacking of a real planispiral stage and for the sutures nearly orthogonal to the median axis (Fig. 9).
In the Piedmont Pliocene assemblages S. wrighti rather commonly occurs, but reaches abundances around 3% only in the Isola d'Asti deep circalittoral-upper epibathyal clays (MPl3-MPl4a zones). Spiroplectinella sp. Pl. 8, Test elongate, compressed, with a planispiral stage both in microspheric and macrospheric forms. About 7-8 pairs of sub-rectangular chambers, slowly increasing in breadth in the biserial adult stage. Sutures distinct, slightly depressed, the chamber upper suture forming an angle with the median axis ranging between 68-82° (Fig. 9). Peripheral margin acute, lobate. Wall smooth, including small regularly arranged inorganic debris, abundant calcareous cement, with parapores. Aperture a low arch at the inner margin of the last chamber, bordered by a thin lip.
Remarks. Few specimens were collected from the circalittoral clayey silts of Incisa S. and in the AA silty clays of the northern Monferrato (Arignano, Verrua S.), all dated to the MPl4a subzone.
Test elongate, tapering, biserial throughout. Aboral part acutely pointed in the microspheric generation, more rounded in the megalospheric one. 6 to 8 pairs of compressed chambers, gradually increasing in size. Sutures straight and oblique, slightly depressed, not or poorly evident in the early chambers, the upper suture forming an angle ranging between 45-60° with the median axis (Fig. 9). Peripheral margin acute to subrounded. Wall thin, fine to medium size grained, including small biogenic debris (molluscs, sponge spicules, foraminifers, calcareous nannofossils), with calcareous cement, canaliculate, outer surface rather smooth. Aperture a medium arch at the inner margin of the last chamber.

Remarks. T. aciculata is often reported from
Italian Pliocene (Terrigi 1880;Fornasini 1887d;1888b¸ Martinis 1954Sampò et al. 1968;Rio et al. 1988;Di Bella et al. 2002), Pleistocene (Coppa et al. 2001; and Recent assemblages Aiello et al. 2021). In the cited literature, it is generally recorded from circalittoral silty to clayey deposits. The species is accepted, as fossil and recent, by WoRMS (2023). On the contrary, Poignant (1998), in her review of some d'Orbigny species, invalidated T. aciculata, as a junior synonym of Textularia angularis d 'Orbigny, 1826. At a first sight, T. aciculata may be confused with S. wrighti, for their apparent similar morphol-ogy. T. aciculata can be differentiated from S. wrighti on the basis of: 1) The absence in T. aciculata of any planispiral juvenil stage, occurring in S. wrighti, verified by the observation of some hundred specimens in transmitted light under a transparency agent (lavander or thuja oil). 2) The angle formed by the upper suture with the median axis ranging between 45-60° in T. aciculata, between 63-72° in S. wrighti) (Fig. 9). 3) The coarser and of less uniform size grains agglutinated in the wall of T. aciculata than in S. wrighti.
Remarks. A cosmopolitan living species, known from the Oligocene (Cushman 1922; Gal-  'Orbigny, 1826, Calliano, 5.5 m, lateral view. Fig. 3 -Textularia aciculata d 'Orbigny, 1826, Calliano, 5.5 m, wall enlargement of specimen in Fig. 2. Fig. 4 (2015) documented its epiphytic life mode on vegetated rocky substrates along the Israeli Mediterranean coasts. The species is rare in most of the studied samples, common only in the lower part of the Isola d'Asti section. The clast granulometry and cement amount can strongly differ, in relation to the more or less sandy sediment, and a range from very coarse (Pl. 9, fig. 7) to a rather smooth wall (Pl. 9, fig. 9) occurred.
Remarks. The species is known from the Miocene of Europe, North America and Caribbean area (Galloway & Heminway 1941;Cicha & Zapletalová 1965;Foresi et al. 1997). In WoRMS (2023) it is considered as synonym of Textularia mariae d'Orbigny, 1846, following the opinion of Papp & Schmid (1985). The specimen figured by these last authors to support their opinion (p. 89, pl. 82, figs. 2-3) appears very different from the d'Orbigny drawnings, for the test general morphology, sutures inclination and chambers growing ratio. T. articulata is here retained as a valid species.
In the Piedmont assemblages, it is very rare, found in silty clays pertaining to the MPl3 zone (Calliano, Isola d'Asti and Verrua S. sections, sample CH83).
Test of medium to large size, biserial, and of variable morphology, ranging between two end shapes, a rather lanceolate form with up to 6-8 pairs of chambers (Pl. 10, fig. 3) and a shorter, stout, more inflated form, subrhomboidal in transverse section, with 4-5 pairs of chambers, rapidly increasing in size, corresponding to Textularia abbreviata d 'Orbigny, 1846 (Pl. 10 , fig. 4). Peripheral margine acute. Sutures more or less distinct, slightly curved and depressed. Wall fine to medium size grained, with abundant calcareous cement. Aperture a small arch at the base of the last chamber.
Remarks. Fornasini (1887b) pointed out the difficulty to separate T. abbreviata from T. gramen and from short ("abbreviate") forms of other Textularia species (Textularia subangulata d 'Orbigny, 1846, Textularia haueri d'Orbigny, 1846. Rasmussen (2005) regarded T. pseudogramen, separated by Chapman & Parr (1937) on the basis of its higher number of chamber than T. gramen, as conspecific of the latter species. Following the opinion of Papp & Schmidt (1985) and of WoRMS (2023), T. abbreviata is here retained as synonym of T. gramen. In the Mediterra-nean area it frequently occurs in sandy circalittoral sediments, recorded down to 345 meter depth in the Gulf of Naples (Sgarrella & Moncharmont Zei 1993). In the Northern Italy and Switzerland Pliocene it is recorded in the form T. abbreviata (Ferasin 1954;Martinis 1954;Violanti & Sassone 2008).
Rare specimens occur in the silty marls and silts of the MPl3-MPl4a zones from Isola d'Asti, Calliano, and Frinco. Cžjžek, 1848 Pl. 10, figs. 5-7 Test of medium size, triangular, biserial throughout, with 10-12 pairs of compressed chambers regularly increasing in size. Sutures distinct, horizontal to slightly curved. Wall very fine grained, with large amount of calcareous cement. Aperture a short slit at the base of the apertural face.
Remarks. Fornasini (1887e) figured and gave a very brief description of the taxon, distinguishing T. ponderosa on the basis of its curved and prominent chambers. The species is limited to the Lower Pliocene (Agip 1982), it is generally rare and recorded from silty and sandy sediments (Sampò et al. 1968;D'Onofrio 1981;Violanti 1987).
In the Pliocene Piedmont succession it is very rare and randomly occurs in silty-sandy deposits. Defrance, 1824 Pl. 11, figs. 1-3 Test lanceolate, compressed, biserial. Chambers rapidly increasing in size in the first 3-4 pairs, then gradually increasing in size. Peripheral margins acute to subrounded, nearly parallel in the adult stage. Sutures straight or slightly curved, indistinct to slightly depressed, the chamber upper suture forming an angle with the median axis near to 90° (Fig. 9). Wall medium to coarse agglutinated, with dominant inorganic debris and abundant calcareous cement, canaliculate. Aperture a short arch at the base of the last chamber.

Textularia sagittula
Remarks. A controversial species, accepted in WoRMS (2023) as T. sagittula, but attributed in literature both to the genus Textularia or to Spiroplectinella. T. sagittula is the type species of the genus Textularia, the "adventitious third chamber against the first pair of chambers in the microspheric generation" (Loeblich & Tappan 1987), could be interpreted as an initial planispiral stage, typical of the genus Spiroplectinella. Parker (1958) placed in synonymity the two species as T. sagittula and reports the taxon highest frequencies shoaler than 201 m in the Eastern Mediterranean. Frontalini et al. (2014) reported the taxon, as S. sagittula, frequent to abundant in the upper 100 m, but also present down to about 600 m in the northern Aegean Sea. Blanc Vernet (1969) reported T. sagittula from infralittoral vegetated sea-floor down to upper bathyal muds.
In the studied succession it is rare, rather common in silty-sandy intervals.  pl. 9,fig. 20. Violanti D. 446 The form differs from the typical T. sagittula only in the last 2-4 pairs of chambers, more inflated in their central part and with more depressed and distinct sutures. The peripheral margin, nearly continous in the approximately first half of the test, is lobate in the uppermost 1 or 2 pairs of chambers.
Remarks. Fornasini (1887a) named this taxon as Textularia sagittula Defrance var. calaritana on one specimen collected from Miocene sediments in the surroudings of Cagliari (Sardinia). In the subsequent paper on the italian textularias (Fornasini 1887b), he figured the specimen, but referred the variety to the species T. luculenta Brady, 1884. It is accepted in WoRMS (2023) at the species level. Tests showing the lobate last pairs of chambers, characteristic of "calaritana", were figured in recent assemblages among typical S. wrighti or S. sagittula (Cimerman & Langer 1991;Milker & Schmiedl 2012). Here it is preferred to mantain the form at the rank of a variety of T. sagittula, if not a morphotype.

Textularia soldanii
Remarks. The species, described by Fornasini (1883) from the Pliocene of Ponticello di Savena (Bologna, Northern Italy), was previously figured, but not described, by Soldani (1791). T. soldanii is common in many shelf to upper slope assemblages from Miocene (Tortonian) to Pleistocene (Agip 1982;Rio et al. 1988). Reported as fossil in WoRMS (2023), it is included in the list of the extant Mediterranean species (Banchetti et al. 2008), without reference source.
Rare specimens occur in clayey-silty sediments, from the upper part of the AA formation of Isola d'Asti, Calliano, Incisa S. sections, and of samples MN, FR3, CH90.
Very rare specimens were collected from the AA clays and silty clays of the Isola d'Asti, Incisa S. and Verrua S. sections and from the SA silty sands at Moncalvo.
Very rare specimens were collected in the AA assemblages of the Isola d'Asti and Verrua S. sections and in sample FR1.
Textularia sp. 1 Pl. 12, Test of lozenge shape, biserial, with 5-8 pairs of chambers, fastly increasing in width. Peripheral margin acute, a keel may be present in the adult stage. The median part of the test, along the axis, is sligtly inflated, giving a distinct median ridge. Sutures oblique, fairly depressed to indistinct. Wall rather thick, medium to coarse agglutinated, almost exclusively made by inorganic clasts, with abundant calcareous cement, and parapores. Aperture a very small arch at the inner margin of the last chamber.
Remarks. Textularia sp. 1 differs from T. aciculata for the more rhomboidal shape of the test, the acute peripheral margin, the evident median ridge and the irregularly agglutinated wall. In the studied area, rare specimens occur in the circalittoral silts and sandy silts assemblages.
Aknowledgements: The author is greatly indebted with Mariano Gallo and Bartolomeo Vigna, for their geological support and fruitful suggestions, with Simona Cavagna for her assistance in SEM analyses and with the Earth Science Department of Turin University for the laboratory and instrumentation availability. The author wishes to thank the editors Lucia Angiolini and Maria Rose Petrizzo, Cristina Lombardo (University A. Desio of Milan) and the reviewers Mike Kaminski (KFUPM), Nicoletta Mancin (University of Pavia) and an anonymous one, for their constructive comments that greatly improved the early version of this paper.