Biodiversity Data Journal :
Taxonomy & Inventories
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Corresponding author: Federico Plazzi (federico.plazzi@unibo.it)
Academic editor: Yasen Mutafchiev
Received: 26 Sep 2022 | Accepted: 15 Mar 2023 | Published: 21 Mar 2023
© 2023 Federico Plazzi, Guido Pedroni
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Plazzi F, Pedroni G (2023) Biodiversity of extant snails (Gastropoda, Mollusca) in the Pliocene Mountain Spur Natural Reserve (Northern Apennine, Italy). Biodiversity Data Journal 11: e95688. https://doi.org/10.3897/BDJ.11.e95688
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To date, there is a substantial lack of information about gastropods from the Tuscan-Emilian Apennine in the north of Italy, notwithstanding the availability of detailed and comprehensive literature on this molluscan class. We present a gastropod fauna from the Natural Reserve of the Pliocene Mountain Spur: to our knowledge, this is the first investigation of the extant gastropod fauna in the Tuscan-Emilian Apennine and one of the few in the Apennine's mountain chain as a whole.
We describe a gastropod fauna comprised by 25 species, belonging to 18 genera and 10 families: the general figure which is emerging is an assemblage of European and Mediterranean-European species, with a single Asian contribution. Several shells were collected as embedded in sandy-clayey soils and showed fossilisation traces: therefore, we regard these shells as subfossil samples. Namely, subfossil shells are from the species Pomatias elegans, Granaria frumentum, Retinella olivetorum, Xerolenta obvia obvia, Oxychilus cf. draparnaudi, Monacha cartusiana and Monacha cantiana. The present checklist is the first report in the Tuscan-Emilian Apennine and Emilia-Romagna areas for six taxa: Morlina glabra glabra, Oxychilius alliarius, Xerosecta cespitum, Fruticicola fruticum, Xerogyra spadae and Xerolenta obvia obvia.
Pliocene Mountain Spur, Tuscan-Emilian Apennine, checklist, molluscan fauna, Gastropoda, Eupulmonata, pulmonate molluscs, subfossils
The order Stylommatophora is by far the best-known and largest order of the superorder Eupulmonata (Gastropoda), including approximately 25,000-30,000 terrestrial species in 104 families (
Currently, 2,087 species of non-marine gastropods are known to inhabit Europe. Amongst these non-marine gastropod species, as many as 1,834 (87.88%) are eupulmonates, of which only 24 (1.31%) are non-stylommatophorans; in Italy, 345 species belonging to Eupulmonata have been detected (
The area of the Pliocene Mountain Spur is a system of rocky outcrops of sandstone dating back to the Pliocene, which ranges between 2.58 and 5.33 million years ago (mya). The Pliocene Mountain Spur encompasses the valleys of rivers Setta, Savena, Zena and Idice; it spans over the Tuscan-Emilian Apennines for a length of about 15 km, covering an approximate surface area of 2,628 ha (Fig.
A map of the Pliocene Mountain Spur Area. The Natural Reserve is highlighted in green; sampling localities are shown with numbers 1-10 and refer to those in Table
Detected species and relative sampling localities. Sampling sites are shown in Fig.
(Sub)Species | Sampling locality | Elevation (m a.s.l.) | Date | Coordinates | Number of samples | Depth (cm) | Subfossils | Habitat |
Pomatias elegans | Fosso Raibano (3) | 231 | 12.IX.2020 |
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> 15 | 0-60 | Yes | Sandy-clayey underbrush |
Pomatias elegans | Monte Mario (1) | 231 | 31.VIII.2020 | 44.3716°N 11.2729°E | > 10 | 0 | No | Grass beside the road |
Pomatias elegans | Monte Mario (slope) (2) | 241 | 17.VIII.2021 |
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3 | 0 | No | Sandy underbrush below sandstone cliff |
Pomatias elegans | Road to Monte Adone (below Campiuno) (6) | 374 | 30.VIII.2020 |
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> 15 | 0-60 | Yes | Grassy slopes along the road |
Pomatias elegans | Campiuno (7) | 421 | 30.VIII.2020 |
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6 | 0 | No | Underbrush slopes with reddish soil |
Pomatias elegans | Road between Monte del Frate and Monte Adone (5) | 336 | 28.VIII.2020 |
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8 | 0 | No | Conglomerate outcrops along the road |
Pomatias elegans | Monte del Frate (basement) (4) | 335 | 6.IX.2021 |
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> 15 | 0 | No | Very high outcrops above the road |
Granaria frumentum apennina | Campiuno (7) | 421 | 31.XII.2018 |
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1 | 0 | No | Underbrush slopes with reddish soil |
Granaria frumentum illyrica | Road between Monte del Frate and Monte Adone (5) | 336 | 28.VIII.2020 |
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2 | 0 | No | Conglomerate outcrops along the road |
Granaria frumentum illyrica | Campiuno (7) | 421 | 31.XII.2020 |
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1 | 0-40 | Yes | Underbrush slopes with reddish soil |
Granaria variabilis | Campiuno (7) | 421 | 31.XII.2018 |
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2 | 0 | No | Underbrush slopes with reddish soil |
Jaminia quadridens quadridens | Road between Monte del Frate and Monte Adone (5) | 336 | 28.VIII.2020 |
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3 | 0 | No | Conglomerate outcrops along the road |
Jaminia quadridens quadridens | Campiuno (7) | 421 | 31.XII.2018 |
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2 | 0 | No | Underbrush slopes with reddish soil |
Euomphalia strigella strigella | Monte Adone (top) (9) | 654 | 13.XII.2021 |
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1 | 0 | No | Sandy plain with sparse shrubs |
Monaca cantiana | Campiuno (7) | 421 | 31.XII.2018 |
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2 | 0-60 | Yes | Underbrush slopes with reddish soil |
Monaca cantiana | Road to Monte Adone (below Campiuno) (6) | 374 | 28.VIII.2020 |
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9, > 15 juv. | 0 | No | Vegetation beside the road towards Brento |
Monacha cartusiana | Lower road to Monte del Frate, curve (4) | 335 | 28.VIII.2020 |
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2 | 0-50 | Yes | At the base of high sandstone walls |
Monacha martensiana | Campiuno (7) | 421 | 5.IX.2021 |
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2 | 0 | No | Underbrush slopes with reddish soil |
Monachoides incarnatus | Campiuno (7) | 421 | 5.IX.2021 |
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4 | 0 | No | Underbrush slopes with reddish soil |
Cornu aspersum | Monte Mario (slope) (2) | 241 | 31.VIII.2020 |
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1 | 0 | No | Sandy underbrush below sandstone cliff |
Helix cincta | Monte Mario (1) | 231 | 31.VIII.2020 |
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> 15 | 0 | No | Grass beside the road |
Helix cincta | Brento (8) | 436 | 28.VII.2020 |
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3 | 0 | No | Sandstone outcrops |
Helix ligata | Monte Mario (slope) (2) | 241 | 31.VIII.2020 |
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2 | 0 | No | Sandy underbrush below sandstone cliff |
Morlina glabra glabra | Monte Mario (slope) (2) | 241 | 31.VIII.2020 |
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1 | 0 | No | Sandy underbrush below sandstone cliff |
Oxychilus alliarius | Monte Mario (slope) (2) | 241 | 31.VIII.2020 |
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1 | 0 | No | Sandy underbrush below sandstone cliff |
Oxychilus cf. draparnaudi | Brento (8) | 436 | 28.VIII.2020 |
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2 | 0-50 | Yes | Sandstone outcrops |
Retinella olivetorum olivetorum | Fosso Raibano (3) | 231 | 12.IX.2020 | 44,3711°N, 11,2742°E | 4 | 0-50 | Yes | Sandy-clayey underbrush |
Retinella olivetorum olivetorum | Road to Monte Adone (below Campiuno) (6) | 241 | 28.VIII.2020 |
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1 | 0 | No | Vegetation beside the road towards Brento |
Candidula unifasciata unifasciata | Monte Mario (slope) (2) | 241 | 17.VIII.2021 |
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2 | 0 | No | Sandy underbrush below sandstone cliff |
Cernuella neglecta | Road to Monte Adone (below Campiuno) (6) | 241 | 28.VIII.2020 |
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2 | 0 | No | Vegetation beside the road towards Brento |
Cernuella cf. virgata | Fosso Raibano (3) | 231 | 12.IX.2020 |
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1 | 0 | No | Sandy-clayey underbrush |
Xerogira spadae | Monte Mario (slope) (2) | 241 | 17.VIII.2021 |
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1 | 0 | No | Sandy underbrush below sandstone cliff |
Xerolenta obvia obvia | Brento, towards Pianoro (10) | 428 | 5.IX.2021 |
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2 | 0 | No | Grassy sandstone outcrops |
Xerolenta obvia obvia | Monte Mario (slope) (2) | 241 | 31.VIII.2020 |
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1 | 0-40 | Yes | Sandy underbrush below sandstone cliff |
Xerosecta cespitum | Road between Monte del Frate and Monte Adone (5) | 336 | 12.VI.2022 |
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2 | 0 | No | Conglomerate outcrops along the road |
Helicodonta obvoluta obvoluta | Lower road to Monte del Frate, curve (4) | 335 | 5.IX.2021 |
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1 | 0 | No | At the base of high sandstone walls |
Fruticicola fruticum | Fosso Raibano (3) | 231 | 12.IX.2020 |
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1 | 0 | No | Sandy-clayey underbrush |
Fruticicola fruticum | Brento, towards Pianoro (10) | 428 | 5.IX.2021 |
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3 | 0 | No | Grassy sandstone outcrops |
The Natural Reserve of the Pliocene Mountain Spur was created in 2006. It covers a narrower area (around 757 ha), consisting of a small-sized, 8 km-long mountain chain between Sasso Marconi and Brento, from the beginning of the Setta Valley. It is included in the Sites of Community Importance and in the Special Protection Areas (SCI/SPA IT4050012), as well as in the Natura 2000 Network (2628 ha); moreover, it is safeguarded under the Emilia-Romagna Regional Landscape Territorial Plan and the established Faunal Oasis.
The molluscan fauna that we present herein is of relevant interest, since the Northern Apennine has seldom been an object of well-structured malacological studies. Data are lacking for the Natural Reserve presented above; comprehensive publications on molluscan fauna of the Northern Apennines (or of smaller areas within) are limited, the most detailed and in-depth study being a work on the area surrounding Pistoia (
The present work contributes to the current knowledge of extant gastropod molluscs of the Pliocene Mountain Spur, with special reference to the superorder Eupulmonata. Furthermore, we also report subfossil samples, i.e. molluscan (in the present case) samples that did not complete the long and complicated physical/chemical fossilisation process (see, for instance,
The faunal list and ecology notes are partly taken from previous work (
Mollusc specimen collection was carried out by exploring several Reserve sites, sampling both from the surface and removing the sandy-clayey sediment derived from erosion, down to a depth of 50-80 cm. Living specimens were collected for all the species of the molluscan fauna presented here; subfossil specimens were also collected for some of them (Table
Study area. a overview of the Pliocene Mountain Spur; b sampling site 1 (Monte Mario); c sampling site 2 (slopes of Monte Mario); d sampling site 3 (Fosso Raibano); e sampling site 4 (base of Monte del Frate); f sampling site 5 (road between Monte del Frate and Monte Adone); g sampling site 6 (road to Monte Adone, below Campiuno); h sampling site 7 (Campiuno); i sampling site 8 (Brento); j sampling site 9 (top of Monte Adone); k sampling site 10 (Brento, towards Pianoro).
Species determination was carried out on conchological characters, relying on the available malacological literature (e.g.,
Shells were deposited and stored in the collection of one of the authors (GP). Each specimen was given a specimen ID; the abbreviation "PMS" stands for "Pliocene Mountain Spur" and each site is followed by the reference number as provided in Table
Shell thick, ovoidal and grossly conical; spire with 4-5 convex coils; pattern reticulated, ranging from beige to light purple; operculum calcareous or chalky. Some specimens were collected on sandy-clayey slopes that line the road connecting Monte del Frate and Monte Adone, down to a depth of 60 cm. Others were collected at similar depths in the underbrush along a creek (Fosso Raibano); finally, some specimens were collected from the underbrush floor. The species is thermophilic and euryecious; it is widespread and present on calcareous soils, in meadows and underbrush, either uncultivated or cultivated, from hills to plains (
Shell cylindrical, short, stubby, brownish; cervical callus thick; grooves thin and regular; normally the aperture shows eight folds and four palatal lamellae, visible from outside (
Shell cylindrical, short, stubby, brownish. Only one specimen out of four was collected at a depth of about 40 cm, near Campiuno on reddish soil. The subspecies is typically found on calcareous soils in the underbrush litter, as well as at the base of rocks, in sunny calcareous areas, on screes and walls (
Shell cylindrical, short, stubby, brownish. Specimens were collected on the sandy underbrush soil, at the surface. The species inhabits environments with calcareous soils, provided that herbaceous or shrubby vegetation is present (
Shell small, grossly stubby and cylindrical; spire with 7-9 coils; four teeth are visible in the aperture, at different levels of development; peristome white; colour beige. Samples were collected on sandy soils beside the road to Monte Adone, at the surface, as well as in underbrush upstream to the road, near Campiuno. This subspecies inhabits calcareous soils and lives on grass and shrubs in sunny areas, as well as under rocks, in crevices and on screes (
Shell solid, globular, ranging from brown to reddish-brown; border of the aperture white; the last part of the last coil leans towards the aperture. Adult specimens of this subspecies inhabit moderately open and sunny habitats, avoiding excessive moisture, as is the case for the top of Monte Adone. It is possible, even if uncommon, to find individuals of this subspecies in deciduous woods, either in the leaf litter or on trunks or in hedgerows and scrub (
Shell globular and thin, with a maximum of six coils; globally whitish and translucent, but the last coil is reddish around the peristome; umbilicus evident, but not completely open. Some specimens were collected down to a depth of 60 cm, below Campiuno. The species inhabits open environments, typically near water bodies and at lower elevations (
Shell delicate, whitish, sometimes beige; peristome edge shows a thin, brown-reddish band; more flattened than M. cantiana. Specimens were collected near to the high sandstone outcrops of Monte del Frate, at a depth of approximately 50 cm. This is a thermophilic species with a wide distribution, inhabiting meadows, cultivated fields, gardens, vineyards, roadsides and ruins (
Shell ranging from whitish to cream, translucent, similar to other species of the genus Monacha, but the shell is more flattened. The species dwells in habitats with grassy vegetation, such as meadows, on calcareous substrates (
Shell ranging from yellowish to brown-reddish, translucent; microsculpture reticulated, regular, very fine; aperture edge is normally reddish, with a whitish band inside; umbilicus very narrow, but open. This thermophilic subspecies (
Background colour from yellowish to beige to greenish; normally 1-5 spiral brown bands are present, well evident, with yellow or white grooves; peristome white, the edge being more or less folded outside; umbilicus closed in adults. The single specimen was collected in the underbrush, at the surface, below the walls of Monte Mario. This species inhabits natural meadows, shrubs, dunes, cultivated fields, as well as gardens (
Colour globally brown; shape globular; suture shallow; whorls thick and rounded; umbilicus open. Specimens were collected beside the road to Monte Adone-Brento, at the surface. This species inhabits grassy habitats, rocky areas and woodlands (
The shell is highly variable; typically, it is large, ranging from beige to brown in colour. Specimens were caught in a sandy underbrush, at the surface. This species is common in dense vegetation along water bodies, as well as in the underbrush, in mountain areas from Northern Apennine to Calabria, sometimes over the timberline (
Shell medium-sized to small; ranging from white to grey, with a dark brown band and other patterns (bands or spots) on the lower region; 5-6 coils are present; peristome thick, sometimes with teeth; umbilicus narrow. Specimens were collected in the underbrush, close to the sandstone walls of Monte Mario, at the surface. Individuals of this subspecies perfer dry environments between rocks and rocky outcrops, dry meadows and walls (
Shell small, with white and brown stripes; shape somewhat flattened; umbilicus well open. Specimens were collected on sandy-clayey slopes in front of the road between Monte del Frate and Monte Adone, at the surface. Normally, this species lives in roadsides and screes, on coastal dunes, as well as in arid grasslands (
Shell with 5-7 coils, variable in colour and shape, with or without bands; umbilicus open; peristome brown in adults. The specimen was collected along the path in the underbrush through the small Raibano Valley, at the surface. The species inhabits dry, open places: arid meadows, ruderal habitats, hedgerows and grassland (
The specimen was collected in the underbrush below the walls of Monte Mario, at the surface. This species typically inhabits cool, moist underbrushes, in rocky grasslands, even at high elevation on the Apennine Mountains (
Shell thick, smooth, medium-sized and flattened; 5-6 coils in adults; background colour white or white-yellowish, with variable bands, ranging from dark brown to black. Some specimens were collected below the walls of Monte Mario at a depth of about 40 cm. The subspecies is typical of xerothermophilic habitats, such as arid meadows (
Shell medium-sized, very variable, ranging from grey to yellow, with variable bands and spots; 5-6 flattened coils are present; peristome whitish or reddish; umbilicus large. The species inhabits meadows, ruderal habitats, roadsides and margins of arable fields (
Shell medium-sized to small, hairy; umbilicus open; ranging from dark brown to brown; flattened above; peristome flattened; lips somewhat thick, white, with a callus in the aperture with three lobes. This subspecies is found in forests under fallen branches, leaf litter and between stones, usually on calcareous substrate; in the Alps, it may reach 1,900 m, but is rarely found above 1,500 m (
The collection site of the present specimen is of particular interest, at the base of sandstone outcrops in a small, moist dell with abundant vegetation - a site which may represent a refugial micro-environment with respect to ecological features of this subspecies.
Shell medium-sized, globular; umbilicus deep; ranging from white to brown in colour. The specimen was collected in the underbrush, at the surface. The species inhabits open meadows, as well as wood leaf litter, edges of woods and bushes in moist habitats (
Shell with five coils; diameter of about 14 mm; deep sutures. The single specimen of M. g. glabra was collected in a sandy underbrush below the walls of Monte Mario. Normally, this subspecies is found in underbrush, rocks and screes on open hillsides, as well as in biotopes in front of caves and in open, moist environments, but also leaf litter of deciduous and coniferous forests (
Shell small, yellow-brown, lucent, flattened, with very few, packed coils. The specimen was collected in the underbrush. This species inhabits the leaf litter in broad-leaved, deciduous forests, as well as woods, fields, rocks and gardens; rarely it also inhabits acidic places, such as conifer plantations (
The shell is similar to O. alliarius, but the colour is darker. Both specimens were collected in the wood upstream to the road to Monte Adone-Brento, at a depth of 40-50 cm. This species inhabits the leaf litter in broad-leaved, deciduous forests; caves, even in depth; vegetation and rocky outcrops with a suitable level of moisture and sheltering (
Shell yellowish-brown, dextral, medium-sized, thin, almost transparent, globular, with 5-6 coils; sutures well evident; umbilicus large, deep, funnel-shaped; peristome unfolded and thin. Some specimens were collected at a depth of up to 50 cm along the Raibano Valley path. Normally, R. o. olivetorum inhabits shady hill and mountain meadows in chestnut and olive woods (
In this work, we report a gastropod fauna comprised of 25 species and subspecies, classified in 18 genera and 10 families (Fig.
Gastropod fauna of the Pliocene Mountain Spur Natural Reserve. a Pomatias elegans (Campiuno); b Granaria frumentum apennina (Campiuno); c Granaria furmentum illyrica (Monte Adone); d Granaria variabilis (Monte Adone); e Jaminia quadridens quadridens (road between Monte del Frate and Monte Adone); f Euomphalia strigella strigella (Monte Adone); g Monacha cantiana (Monte Adone); h Monacha cartusiana (Monte del Frate); i Monacha martensiana (Campiuno); j Monachoides incarnatus (Campiuno); k Cornu aspersum (Monte Mario); l Helix cincta (Monte Mario); m Helix ligata (Monte Mario); n Morlina glabra glabra (Monte Mario); o Oxychilus alliarius (Monte Mario); p Oxychilus cf. draparnaudi (Brento); q Retinella olivetorum olivetorum (Fosso Raibano); r Candidula unifasciata unifasciata (Monte Mario); s Cernuella neglecta (Brento); t Cernuella cf. virgata (Fosso Raibano); u Xerogyra spadae (Monte Mario); v Xerolenta obvia obvia (Monte Mario); w Xerosecta cespitum (Monte Adone); x Helicodonta obvoluta obvoluta (Monte del Frate); y Fruticicola fruticum (Fosso Raibano).
Still, the present data should be taken as preliminary and further investigation is needed to completely characterise pulmonate molluscs in the Pliocene Mountain Spur Natural Reserve. Taxonomic work is still needed and consensus has not been reached on some of the present names: for example, Cornu aspersum (O. F. Müller, 1774) is listed as Helix aspersa Müller, 1774 by some authors (for instance,
Many species are associated with calcareous soils, which result from Pliocene sandstone geochemistry, that commonly present calcareous components (
Some taxa are xerothermophilic, meaning that they are associated with xeric areas, which are common in the Reserve because of the microclimate of some sites, such as the base of sandstones walls, which are, in some cases, 100 m high and more (Monte Mario, Rocca di Badolo, Monte Adone). These species are Xerolenta obvia obvia, Euomphalia strigella strigella and Monachoides incarnatus incarnatus, which are definitely xerothermophilic species and should be taken as guide species for these environments, but also Granaria variabilis, Cernuella neglecta and Cernuella cf. virgata. Pomatias elegans and J. q. quadridens are also associated with, but not exclusive of, xeric environments.
It is of particular interest the discovery of Helicodonta obvoluta obvoluta, since it is associated with mountain cool, moist climates. It was collected in a small, moist dell below Monte del Frate along the road to Monte Adone, which, therefore, should be considered as a refugial zone because of its microclimatic conditions.
In broad-leaved, deciduous underbrush and along water bodies, as is the case for the small valley of Fosso Raibano (Fig.
Several shells were collected at variables depths (20-60 cm) in sandy-clayey soils and show fossilisation traces, such as the loss of the original colour and the absorption or assimilation of that of the embedding sediment. Therefore, we consider these shells to be subfossil samples (
It is well known (e.g.
Immediately after death, organic matter decomposes; skeletal parts are disjointed, which, for Gastropods, means separating the shell from the operculum; then, maceration can take place in aquatic environments (
The conservation status of subfossil specimens is compatible with the appearance of these species in the focal area in the upper Pliocene (end of the Piacenzian, which spans 3.6-2.58 million years ago) or in more recent times (Pleistocene, Holocene), pointing towards a stable presence up to extant populations.
Concluding, the present checklist is the first report in the Tuscan-Emilian Apennine and Emilia-Romagna areas for four taxa: Morlina glabra glabra, Oxychilius alliarius, Xerosecta cespitum and Fruticicola fruticum; moreover, two taxa are reported here for the first time from the entire Northern Apennine (and Emilia-Romagna as well): Xerogyra spadae and Xerolenta obvia obvia.
We are deeply indebted to Giano Della Bella, Daniele Scarponi and Chiara Torchi for their invaluable help and contribution to species determination. Thanks are also due to an anonymous reviewer, whose suggestions and criticism greatly improved the original manuscript.
GP conceived and supervised the study, collected the specimens and drafted the manuscript. FP wrote the original manuscript, analysed and updated the taxonomic information and finalised the checklist. Both authors revised, read and approved the final manuscript.