Bollettino della Società Paleontologica Italiana, 48 (1), 2009, 15-19. Modena, 15 maggio 200915

Description of Aclis aurisparva n. sp. (Gastropoda, Aclididae) from the Pliocene of Emilia Romagna (N Italy)

Luca BERTOLASO & Vittorio GARILLI

L. Bertolaso, Via Manzotti 35, I-42015 Correggio (Reggio Emilia), Italy. V. Garilli, APEMA Research and Educational Service, Via Alla Falconara 34, I-90136 Palermo, Italy; [email protected]

KEY WORDS - Gastropoda, Aclididae, Aclis new species, Pliocene, N Italy.

ABSTRACT - A new species of the family Aclididae is described from the Pliocene of Emilia Romagna (Northern Italy) as Aclis aurisparva n. sp. This species was formerly reported as Chileutomia (?) sp. (family Eulimidae) but the finding of new, well preserved material has allowed a correct systematic placement. This new species and other similar Mio-Pliocene congeners, with apparently-polished-shells (Italian and Turkish material, under study) close to the A. attenuans - A. walleri group, allow us to hypothesise that the Aclis species with smooth shells (or with a spiral microsculpture) from the Mediterranean Upper Neogene are more numerous than expected.

RIASSUNTO - [Descrizione di Aclis aurisparva n. sp. (Gastropoda, Aclididae) dal Pliocene dell’Emilia Romagna (N Italia)] - Sulla base di nuovi ritrovamenti di materiale ben preservato, proveniente dal Pliocene (presumibilmente Zancleano-primo Piacenziano) dell’Emilia Romagna, viene ridiscussa la posizione sistematica del taxon precedentemente riportato come Chileutomia (?) sp. (famiglia Eulimidae). Tale taxon, qui descritto come Aclis aurisparva n. sp., è caratterizzato da una minuta ornamentazione spirale sulla teleoconca e da un marcato processo labiale varicoso il quale forma una caratteristica espansione del labbro esterno, particolarmente sviluppata negli esemplari subadulti. Aclis aurisparva n. sp. è confrontabile con A. attenuans e A. walleri, rispettivamente viventi in Mediterraneo ed Atlantico orientale, e con alcune specie fossili congeneriche ad esse particolarmente affini (in studio). La descrizione di questo taxon, e l’osservazione di altro materiale inedito, utilizzato per confronto, consentono di suggerire che le Aclis spp. lisce (o provviste di una fine microscultura spirale) del Neogene mediterraneo costituiscano un gruppo più numeroso di quanto desumibile dalla letteratura malacologia.

INTRODUCTION the Lower Pliocene-Lower Pleistocene “Argille Azzurre” (Vai, 1988) or “Argille di Lugagnano” (Arrigoni et al., Garilli & Messina (2006) recently discussed the 1965) formation (Losacco et al., 1964; Cita et al., 2006; occurrence of the eulimid gastropod genus Chileutomia Bosellini et al., 2003). The lower circalittoral to Tate & Cossmann in Tate, 1898 in the Pliocene to Recent epibathyal molluscan assemblage from this outcrop is Mediterranean area and described a possible new species, comparable with that from the Piacenzian of Campore reported as Chileutomia (?) sp., from the Pliocene of (as described by Raffi & Taviani, 1985), though the former North Italy (Emilia Romagna, Campore). In the present has a lower diversity. Anyway a prudent approach suggests paper we rediscuss the systematic attribution of this taxon that an Early to early Middle Pliocene age could be on the basis of new well preserved shells from the same assigned to the deposit of Ca’ de Fii, as supported by the area and a new species of the family Aclididae is occurrence of Mitrella compta (Bronn, 1831) and, described. subordinately, Cerithiella genei (Bellardi & Michelotti, 1840) (see Marasti & Raffi, 1976 and 1977 for their stratigraphic meaning). Actually these species are MATERIALS AND METHODS representative of the Mediterranean Upper Neogene molluscs of tropical affinities, whose extinction occurred The study material consists of six shells, collected in in the early Piacenzian, approximating the Mammoth the last two decades by one of us (L.B.) from the Pliocene Subchron (Raffi & Marasti, 1982). sediments of Emilia Romagna, Northern Italy. In Four shells (holotype and paratypes 1-3) were studied particular, five shells (L. Bertolaso collection) were by the scanning electron microscope using a Philips XL recovered from the Lower Pliocene (Piacenzian) clayey 30 ESEM. Particular attention was given to protoconch beds cropping out at the Campore quarry (Salsomaggiore and teleoconch microsculpture as possible taxonomic Terme, Parma, N Italy), the same locality where the characters at species level. The number of protoconch broken shell of Garilli & Messina (2006) was collected whorls was counted according to Verduin’s method (see Raffi & Taviani, 1985; Bianucci, 1997; Bertolaso & (1977). Palazzi, 1997, and Channel et al., 1994 for geographical location, paleoecological and stratigraphic information on this outcrop). One shell (L. Bertolaso collection) was SYSTEMATICS recovered from the clays cropping out near Ca’ de Fii, about 3.5 Km N of Castellarano (Reggio Emilia). As far The systematics of the family Aclididae, as well as as we are aware, no detailed stratigraphic information is other supposed Ptenoglossa (see Collin, 2002 and 2004 available for the deposit of Ca’ de Fii which belongs to for a short overview on this suborder), is still uncertain.

ISSN 0375-7633 16 Bollettino della Società Paleontologica Italiana, 48 (1), 2009

According to Warén (in Giannuzzi-Savelli et al., 1999, numerous growth scars running from suture to suture p. 7) most part of the genera and species traditionally and irregularly spaced. Growth scars sinuous, included in this family could be placed in the prosocirte and opisthocirte in the abapical and in the Heterobranchia, as suggested by some data from living adapical portion of the whorl respectively. Protoconch/ species. For the moment being, we maintain the placement teleoconch boundary marked by a sinuous scar. in the Ptenoglossa, following the systematic proposed Teleoconch formed by 2.5-5 strongly convex whorls by Giannuzzi-Savelli et al. (1999). often bearing expanded varicose labial processes and forming a moderately pronounced subsutural ramp in the area near the varicose processes. Labial processes Class GASTROPODA Cuvier, 1797 are evident from the penultimate whorl and may be Order NEOTAENIOGLOSSA Haller, 1882 well to moderately expanded adapically and clearly half- Suborder PTENOGLOSSA Gray J.E., 1853 detached, or reduced to very few detached prominent Superfamily JANTHINOIDEA Lamarck, 1810 scars. Angular distance between them of about 90° and Family ACLIDIDAE Sars G.O., 1878 180°. Teleoconch microsculpture consisting of Genus Aclis Lovén, 1846 numerous (35-40 on the penultimate whorl of paratype 2), fine and moderately raised spiral threads, somewhat Type species - Alvania supranitida Wood S.V., 1842 discontinuous, becoming coarser and more closely by monotypy. spaced on subsutural area. Teleoconch is crossed by irregularly spaced, moderately marked and slightly curved, opisthocline growth lines, and few rough and Aclis aurisparva n. sp. very irregular raised scars. Sutures slightly inclined and (Pl. 1, figs. 1-15) moderately deep. Last whorl making up little more than one half of the total shell height. Aperture ovate, higher 2006 Chileutomia (?) sp. GARILLI & MESSINA, pp. 198-199, Fig. than broad, extended in its lower part, making up about 1c, Pl. 1, figs. 6-7, 9-10. two thirds of last whorl height and one third of total shell height. Outer lip flattened in the lower part, and Description - Shell conical, macroscopically folded in the remaining part, where a sort of slight polished, rather thin and minute, 2.5 mm in height and concavity occurs along the edge. This concavity 0.95 mm in width (in holotype). Protoconch multispiral, appears deeper on the uppermost area, close to the conical and elongated, 0.6 mm in height (paratype 1), with contact with the body whorl, where the lip expansion a rather immersed nucleus and slightly convex whorls. may form a short wing-shaped extension, making the Protoconch I consisting of little less than one smooth peristoma ear-shaped. Inner lip curved and with a thin whorl; protoconch II formed by about 2.3 whorls, with expansion which is narrower along the columellar side.

EXPLANATION OF PLATE 1 figs. 1-5 - Aclis aurisparva n. sp. Pliocene of Campore, Salsomaggiore Terme, Parma, N Italy. 1 - Protoconch of paratype 1 (MZB45638), showing the sinuous scars. 2 - Protoconch of paratype 1 (MZB45638), showing the sinuous scars, the protoconch I/protoconch II (black arrow) and protoconch/teleoconch boundaries (white arrows). 3 - Protoconch of paratype 1 (MZB45638), showing the sinuous scars and protoconch/teleoconch boundary (white arrows). 4 - Protoconch of paratype 2 (MZB45639), showing the sinuous scars. 5 - Protoconch of paratype 1 (MZB45638), showing the sinuous scars and the protoconch I/protoconch II boundary (black arrow). figs. 6-7 - Aclis aurisparva n. sp. Holotype (H = 2.5 mm, MZB45642). 6 - Apertural view of the shell. 7 - Detail of teleoconch microsculpture. figs. 8-10 - Aclis aurisparva n. sp. Paratype 1 (H = 1.3 mm, MZB45638). 8 - Apertural view of the shell. 9 - Dorsal view of the shell. 10 - Detail of the upper part of the outer lip. figs. 11, 13-15 - Aclis aurisparva n. sp. Paratype 2 (H = 1.2 mm, MZB45639). Pliocene of Campore, Salsomaggiore Terme, Parma, N Italy. 11 - Detail of the umbilical chink. 13 - Apertural view of the shell. 14 - Dorsal view of the shell. 15 - Detail of the spiral microsculpture. fig. 12 - Dorsal view of paratype 3 (H=1.3 mm, MZB45640), Pliocene of Ca’ de Fii, Castellarano, Reggio Emilia, N Italy.

Scale bars = 100 μm in figs. 1-4, 10-11; = 50 μm in figs. 5, 7, 15. L. Bertolaso, V. Garilli - A new Pliocene aclidid gastropod Pl.17 1 18 Bollettino della Società Paleontologica Italiana, 48 (1), 2009

Narrow umbilical chink, partially covered by the example, the Mediterranean Aclis attenuans Jeffreys, expansion of the inner lip. 1883 and the Atlantic A. walleri Jeffreys, 1867 have a general shell shape very close to that of Aclis aurisparva Type material - Holotype and paratypes 1-4 are n. sp., with which they also share the expansion of the housed in the Museo di Zoologia of the University of lower part of the aperture, the shape of the umbilicus Bologna (MZB), paratypes 5 and 6 are housed in the and the occurrence of numerous irregular scars, the Dipartimento di Geologia e Geodesia of the University last two features being common in the genus Aclis (see of Palermo (DGUP), coll. V. Garilli. Bouchet & Warén, 1986, fig. 726-727 and 730-732 Holotype (2.5 mm x 0.95 mm, catalogue number for Recent shells of A. attenuans and A. walleri and Di MZB45642), paratype 1 (1.3 mm x 0.6 mm, catalogue Geronimo & La Perna, 1997, pl. 4, fig. 10 for Pleistocene number MZB45638), paratypes 2 (1.2 mm in height, A. attenuans). Also the sinuous scars occurring on catalogue number MZB45639), 4 (1,2 mm in height, protoconch II are very similar to that shown by A. walleri. catalogue number MZB45641), 5 (catalogue n° The extremely fine spiral striation shown by A. CAPA001/536, ex F75A coll. S. Palazzi, the broken shell aurisparva n. sp. is another significant character. This illustrated by Garilli & Messina, 2006, pl. 1, figs. 6-7, 9- microsculptural pattern is not found in the Epitonidae and 10 and Fig. 1c) and 6 (1.05 mm x 0.5 mm, catalogue scarcely represented in the Eulimidae, but seems number DGUP CAPA002/537) are from the Pliocene widespread in the family Aclididae: e.g. Aclis crassilirata deposit at the Campore quarry, Salsomaggiore Terme, (Cossmann, 1900), Eocene of France, Bois Gouët; A. Parma, Emilia Romagna, North Italy; paratype 3 (1.3 mm carolinensis Bartsch, 1911, North Carolina, Recent; A. in height, catalogue number MZB45640) is from the thesauraria Melvill, 1904, Gulf of Oman, Recent (A. Pliocene clays cropping out at an abandoned quarry next Warén, 2008, pers. comm.). Also the supposed Aclididae to Ca’ de Fii, about 3.5 Km N of Castellarano, Reggio Hemiaclis hyalina (Watson, 1880), from the north- Emilia, North Italy (44°32’16”N 10°45’00”E). eastern coasts of Brazil (Mello et al., 2003), shows a similar sculpture (see Mello et al., 2003, fig. 1e). A spiral Type locality - The Pliocene bluish clay cropping out microsculpture similar to that of Aclis is present in some in the Campore quarry, Salsomaggiore Terme, Parma, eulimids, such as Pelseneeria Koeler & Vaney, 1908 (see North Italy. P. striata Bouchet & Warén, 1986, figs. 994-995), whereas other genera of the same family (e.g. Etymology - After the Latin auris (ear) and parva Amamibalcis Kuroda & Habe, 1950, Annulobalcis Habe, (small), referring to the ear-shaped peristoma, more 1965, Arcuella Nevill, 1874 and Trochostilifer Warén, clearly shown by paratype 1. 1980) have different, much more pronounced spiral sculpture (see Warén, 1984 and Warén et al., 1984). Distribution - Aclis aurisparva n. sp. is only known Aclis aurisparva n. sp. shows a remarkable range from the Pliocene (possibly Zanclean to early of variation in shape. Whereas the paratype 1 shows a Piacenzian) lower circalittoral to epibathyal deposits more slender, elongate shell, paratypes 2 and 3 have from Campore and Ca’ de Fii, Emilia Romagna (N Italy). broader shells. Following Bouchet & Warén (1986), this variation, rather common in the genus Aclis, is Comparisons and remarks - The general shell shape, likely due to sexual dimorphism (see Bouchet & Warén, the characters of protoconch and aperture, and the fine 1986, pp. 726-727 and 730-732 for A. attenuans and spiral sculpture exclude the placement of this species in A. walleri and Giannuzzi-Savelli et al., 1999, figs. 110 Chileutomia Tate & Cossmann in Tate, 1898. This genus and 111 for A. attenuans and A. gulsonae (W. Clark, is characterized by more markedly varicose shell with an 1850)). We noted the same variation among some almost pyriform aperture provided with a sinus in the upper Mediterranean Mio-Pliocene (from North Italy and part of the outer lip. Admittedly, the characteristic South Turkey, L. Bertolaso collection) apparently incremental scars (also forming varicose labial smooth Aclis spp., more or less related to the A. processes) occurring in Aclis aurisparva n. sp. are quite attenuans-A. walleri group or with a somewhat common in the families Muricidae, Cymathiidae and angulated base. Epitoniidae, and even vetigastropods show similar processes (A. Warén, 2008, personal communication). Expanded labial processes also occur in the genus CONCLUDING REMARKS Hoplopteron Fischer, 1876, tentatively assigned to Eulimidae (Warén, 1984). However this genus (as Chileutomia miranda (Dautzenberg, 1925) remains illustrated by Warén, 1984, fig. 108) shows markedly the sole known representative of its genus in the Pliocene expanded varices, its aperture is almost pyriform, and the to Recent Mediterranean area, whereas Chileutomia (?) teleoconch whorls lacks ornamentation and are less sp. of Garilli & Messina (2006) is proved to be an aclidid convex, particularly when comparing with the Eocene species, herein described. type species of Ptereulima (a synonym of Hoplopteron Aclis aurisparva n. sp. is well characterized by its according to Warén, 1984, p. 68, fig. 161). ear-shaped peristoma and the presence of a The general teleoconch and protoconch shape, and the microsculpture, and cannot be confused with congeners. ovate aperture of the new species indicate a strong affinity It is noteworthy that among the recorded Aclis species with Aclididae, though all these characters may also occur from the Mediterranean Pliocene (Tabanelli, 1997, listed with similar patterns in the families Epitoniidae and 14 Plio-Pleistocene species from Italy) only A. Eulimidae (A. Warén, 2008, pers. comm.). As an attenuans (including the Mediterranean citation of A. L. Bertolaso, V. Garilli - A new Pliocene aclidid gastropod 19 walleri), A. brugnoniana De Stefani & Pantanelli, 1879 Geologica d’Italia 1:50.000, Quaderni serie III, Volume 7, and A. gulsonae var. subappenninica Sacco, 1891 (the Fascicolo VII, 382 pp. last two are poorly known, needing to be revised) have, Collin R. (2000). Development and Anatomy of Nitidiscala tincta (Carpenter, 1885) (Gastropoda: Epitoniidae). The Veliger, at least apparently, no spiral sculpture. However the 43 (4): 302-312. occurrences of the Pliocene A. aurisparva n. sp. and Collin R. (2004). Development of Cerithiopsis gemmulosum the above mentioned Mio-Pliocene undetermined Aclis (Gastropoda: Cerithiopsidae) from Bocas del Toro, Panama. spp. (our material from Italy and Turkey, under study) Caribbean Journal of Science, 40 (2): 192-197. allows to suppose that more (macroscopically) polished Di Geronimo I. & La Perna R. (1997). Pleistocene bathyal molluscan aclidid species lived in the Mediterranean area during assemblages from Southern Italy. Rivista Italiana di Paleontologia e Stratigrafia, 103 (3): 389-426. the Neogene. Garilli V. & Messina R. (2006). The genus Chileutomia (Gastropoda: Eulimidae) in the Pliocene to Recent Mediterranean area. Bollettino della Società Paleontologica Italiana, 45 (2-3): 195- ACKNOWLEDGMENTS 200. Giannuzzi-Savelli R., Pusateri F., Palmeri A. & Ebreo C. (1999). We would like to thank Anders Warén (Swedish Museum of Atlante delle conchiglie marine del Mediterraneo Vol. 3 Natural History, Stockholm) for the useful discussion and comments (Caenogastropoda parte 2: Ptenoglossa). Evolver, Roma, 127 on the systematic placement of Aclis aurisparva n. sp. He also pp. reviewed the submitted manuscript. Thanks are also due to Luca Losacco U., Ghizzoni G., Pistolesi A., Serpagli E. & Zappelli A. Galletti (APEMA, Research and Educational Service, Palermo) for (1964). Carta Geologica d’Italia al 100.000: Foglio 86 (Modena). the help in providing SEM images. We are grateful to Marina Cantelli Servizio Geologico d’Italia. and Bruno Sabelli (Museo di Zoologia, University of Bologna) who Marasti R. & Raffi S. (1976). Osservazioni biostratigrafiche e provided catalogue numbers. 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