From the Middle Pleistocene of the Mercure Basin (Southern Italy)
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TO L O N O G E I L C A A P I ' T A A T L E I I A Bollettino della Società Paleontologica Italiana, 55 (1), 2016, 23-28. Modena C N O A S S. P. I. Emmericia lucana n. sp. (Caenogastropoda) from the Middle Pleistocene of the Mercure Basin (southern Italy) Daniela ESU, Odoardo GIROTTI & Emanuela PISegNA CERONE D. Esu, Dipartimento di Scienze della Terra, Università “Sapienza”, P.le A. Moro 5, I-00185 Roma, Italy; [email protected] O. Girotti, Dipartimento di Scienze della Terra, Università “Sapienza”, P.le A. Moro 5, I-00185 Roma, Italy; [email protected] E. Pisegna Cerone, Via Paolo Rembrandt 22, I-20148 Milano, Italy; [email protected] KEY WORDS - Freshwater gastropods, Emmericiidae, Systematics, Southern Italy, Middle Pleistocene. ABSTRACT - The intramontane Mercure Basin occupies a broad area within the Basilicata region (southern Apennines, Italy) located between Mt. Pollino to the SE and the Lauria Mts to the NW. It comprises non-marine deposits varying from coarse fluvial gravels and sands at the base, to fine, lacustrine, calcareous muds at the top. Large mammals, freshwater molluscs and tephrostratigraphical analyses indicate a Middle Pleistocene age for these deposits. A new extinct and endemic species, Emmericia lucana n. sp., representative of the Family Emmericiidae (Caenogastropoda, Truncatelloidea), was found among the rich malacological assemblages of the lacustrine layers and is herein described. It is the first record of the genusEmmericia Brusina, 1870 in the Middle Pleistocene of Italy. RIASSUNTO - [Emmericia lucana n. sp. del Pleistocene Medio del Bacino del Mercure (Italia meridionale)] - Il bacino intramontano del Mercure occupa in Basilicata una vasta area compresa tra il massiccio del Pollino a SE ed i monti di Lauria a NW. Si tratta del riempimento pleistocenico di una depressione di origine tettonica, i cui sedimenti passano da ghiaie grossolane e sabbie, alla base, a limi calcarei lacustri fini e laminati al tetto. La loro età medio-pleistocenica è indicata dalla presenza di grandi mammiferi e molluschi dulcicoli, oltreché da analisi tefrostratigrafiche. Una nuova specie estinta ed endemica della Famiglia Emmericiidae (Caenogastropoda, Truncatelloidea), Emmericia lucana n. sp., è stata rinvenuta nelle ricche associazioni malacologiche dei limi lacustri. Si tratta del primo rinvenimento del genere Emmericia Brusina, 1870 nel Pleistocene Medio italiano. INTRODUCTION freshwater molluscan assemblages (Cavinato et al., 2001; Mancini et al., 2004; Esu & Pisegna Cerone, 2008). More The Mercure Basin, located NW of the Pollino Mt. recently, the biochronological datum was confirmed by and SE of the Lauria Mts close to the Calabria-Basilicata tephrostratigraphical analyses (40Ar/39Ar dating, 87Sr/86Sr boundary, is a southern Apennine intramontane basin and 143Nd/144Nd isotope ratios) performed on the tephra of tectono-sedimentary origin, wide about 80 km2., at layers, allowing to refer the study succession to the late around 300-500 m a.s.l. It is incised by the Mercure River Marine Isotope Stage (MIS) 15-12 interval (560-440 ka) and filled with a non-marine Pleistocene stratigraphic (Giaccio et al., 2014; Petrosino et al., 2014; Robustelli et succession, not less than 300 m-thick and subdivided into al., 2014), confirming the Middle Pleistocene age. Field two main stratigraphic sub-units (Mancini, 2004; Mancini investigations for palaeontological purposes, carried out et al., 2004; Giaccio et al., 2014). Mainly coarse gravel by the authors in the whole Mercure Basin during the years deposits passing to fine sands, silts and lignite make up 1996-2003, led to record a noteworthy array of freshwater the lower sub-unit, mostly cropping out in the central gastropods and bivalves from several stratigraphical part of the basin (Calorie, Fig. 1). This sub-unit yielded sections of the upper sub-unit (Pisegna Cerone, 2007; a well-preserved middle Galerian mammal assemblage Esu & Pisegna Cerone, 2008). The recorded assemblages (Cavinato et al., 2001), and rare fluvio-lacustrine molluscs are dominated by aquatic prosobranchs, and locally by of low-energy environment, such as few remains of bivalves. Bithynia leachii (Sheppard, 1823) with opercula, Valvata piscinalis (Müller, 1774) and Pisidium sp. The alluvial deposits of the lower sub-unit pass upward, in the whole MATERIALS AND METHODS basin, to whitish-yellowish finely laminated calcareous lacustrine mud (varve-like) of the upper sub-unit, up to The new species described in this paper was recovered 100 m thick. Thin tephra layers and abundant freshwater from different sites and distinct layers of the following lacustrine molluscs characterize it. These deposits of open stratigraphical sections of the upper lacustrine sub-unit: to marginal lacustrine environment extensively crop out CIC, VA, S1, S4, LS in the western sector of the basin, and in the basin (Mancini et al., 2004; Pisegna Cerone, 2007; S2, MES1, MES2, MES3 in the eastern sector (Fig. 1). A Esu & Pisegna Cerone, 2008). The sedimentary infilling of detailed sampling was carried out for each section. All the the basin was referred to the Middle Pleistocene by means beds yielded numerous fossil remains, such as molluscs of the record of well-preserved large mammal assemblage (shells and opercula), ostracods and terrestrial plant related to the middle Galerian Large Mammal Age remains. A total of 361 specimens of Emmericia lucana (700-550 ka), and of the presence of Middle Pleistocene n. sp. was collected. The malacological material studied ISSN 0375-7633 doi:10.4435/BSPI.2016.03 24 Bollettino della Società Paleontologica Italiana, 55 (1), 2016 Fig. 1 - Geological map of the Mercure Basin and location of the investigated stratigraphic sections. 1) Alluvial fan gravels and sands (Middle Pleistocene); 2) lacustrine whitish calcareous muds with tephra layers and molluscs (upper sub-unit, Middle Pleistocene); 3) fluvial gravels and sands with large mammal remains (lower sub-unit, late Lower-Middle Pleistocene); 4) Sant’Arcangelo Basin (Middle-Upper Pliocene); 5) Frido Unit (Cretaceous-Eocene); 6) Pollino Unit (Triassic-Miocene); 7) normal and transtensional faults; 8) CIC, VA, S1, S4, LS, S2, MES1, MES2, MES3, stratigraphic sections (from Cavinato et al., 2001 and Giaccio et al., 2014, modified). in this paper is stored at the Museo di Paleontologia Etymology - From Lucania, an ancient district of dell’Università “Sapienza” di Roma (collection Esu- southern Italy, extending from the Tyrrhenian Sea to Girotti, MPUR7). the Gulf of Taranto, comprising the modern region of Gastropod taxonomy follows that of Bouchet & Rocroi Basilicata. (2005), and the FreshGen database (Neubauer et al., 2014). Locus typicus and stratum typicum - Castelluccio inferiore (Basilicata), 40°00’03,44”N, 15°58’53,05”E; SYSTEMATIC PALAEONTOLOGY calcareous silt and marls of the upper sub-unit of the Mercure Basin, Middle Pleistocene. Class GASTROPODA Cuvier, 1795 Subclass CAENOGASTROPODA Cox, 1960 Type material - Holotype, MPUR7-3291 (Section Order LITTORINIMORPHA Golikov & Starobogatov, 1975 CIC); Paratypes, MPUR7-3287/2. Superfamily TRUNCATELLOIDEA Gray, 1840 Family EMMERICIIDAE Brusina, 1870 Additional material - CIC, MPUR7-2111/77; VA (Vallecola), MPUR7-3268/1; S1, MPUR7-3283/25; S4, Genus Emmericia Brusina, 1870 4 lost specimens; LS (Laino strada), MPUR7-4114/4; S2, MPUR7-2287/5, MPUR7-2303/1; MES1, MPUR7- Type species Paludina patula Brumati, 1838, Recent, 2109/9; MES2, MPUR7-4115/2; MES3, MPUR7- Monfalcone (Gorizia). 3231/227, MPUR7-3115/3. Emmericia lucana n. sp. Age - The new species is known only from the Middle (Pl. 1, figs 1-7) Pleistocene of southern Italy (Mercure Basin, Basilicata). 2008 Emmericia cf. narentana Bourguignat - ESU & PISegNA Diagnosis - A species of the genus Emmericia, with CERONE, p. 152. conical-elongated and high spired shell; apex large, flat, D. Esu et alii - Emmericia lucana n. sp. from the Middle Pleistocene of Italy 25 obliquely truncated; protoconch smooth, with 1.5 whorls; E. expansilabris Bourguignat, 1880 and E. ventricosa five whorls nearly flattened, axially striated, provided Brusina, 1870, which appear smooth and without varix, or not with a carina; aperture ovate, peristome weakly although both can show a very weak carina on the last expanded, slightly reflected; last whorl provided or not whorl (Radoman, 1967). E. lucana n. sp. differs from E. with an axial swelling (varix) behind outer lip. Umbilicus expansilabris in having tapered shell, less convex whorls, small, nearly closed. slightly reflected peristome margins, and in some cases an evident carina on all the whorls; from E. ventricosa Description - Shell small-sized, conical-elongated, in being more slender and elongated, higher-spired, with high spired, tapered, with five whorls slightly convex less convex whorls and a proportionally smaller last to nearly flattened, provided or not with a thin carina whorl, and in having an evident carina on all the whorls running in the lower part of the whorls, nearly close in some cases. Among fossil species, the only described to the suture, and in the middle of the last whorl. Last carinate form is Emmericia multicarinata Rust, 1997, whorl large, convex, high about 2/3 of total height, from the Pliocene of Greece (Rust, 1997), which differs somewhat descending in some specimens, mainly in the from E. lucana n. sp. in being smaller and bearing up carinate form. Suture weakly incised and linear. Apex to five carinae. Both E. krizanici Brusina, 1902 and E. large, flat, slightly