Research Article ISSN 2336-9744 The journal is available on line at www.ecol-mne.com http://zoobank.org/urn:lsid:zoobank.org:pub:A6EF195D-2F65-49F8-B5C6-CCFF9ED23E3E Tandonia bolensis n. sp., a new slug (Gastropoda: Pulmonata: Milacidae) from the island of Bra č (Dalmatia, Croatia) WILLY DE MATTIA 1* & GIANBATTISTA NARDI 2 1 International Centre for Genetic Engineering and Biotechnology (ICGEB) Padriciano, 99. 34149 Trieste, Italy, E- mail: [email protected].* Corresponding author. 2 Via Boschette 8/A, I-25064 Gussago (BS), Italy, E-mail: [email protected] Received 11 September 2014 │ Accepted 24 September 2014 │ Published online 25 September 2014. Abstract The genus Tandonia Lessona & Pollonera, 1882 is represented along the Western Balkans by about 13 taxa, most of which are regional endemics. Recent collecting on the island of Bra č (Croatia) has provided a single, fully grown specimen of a totally black slug. A careful investigation of the genital anatomy and body traits, reveal characteristic and unique morphological features which until now have never been observed in other representatives of the genus. Such results have led to the description of new species. Tandonia bolensis n. sp. is easily distinguishable by virtue of its genital features, the dummy-like penial-atrial papilla, and the long and partially spiral-convoluted, thorny spermatophore. Key words : Tandonia bolensis n. sp., Milacidae, Bra č island, Dalmatia, taxonomy, systematics, biogeography, Western Balkans, Mollusca. Introduction The slug family Milacidae Ellis, 1926 is represented by two genera: Milax Gray, 1855, with about 12 known species and Tandonia Lessona & Pollonera, 1882, with more than 30 species currently considered valid. The family has a Euroasiatic-Macaronesian distribution and its centre of diversity is in the Mediterranean, especially in the former Yugoslavia and Greece (Wiktor 1983a, 1983b, 1987a 1996; Abbes et al . 2010; Welter-Schultes 2012; Bank 2013). Along the Western Balkans (from Istria southward, via Dalmatia as far as the Montenegrin coast) up to 13 taxa, belonging to Tandonia , are present and most of them are regional endemics (see Tab. 1). The most important diagnostic features are the morphology of the genitalia and the spermatophore, while the body (shape, coloration and size), the shell and other features such as the jaw or radula have been proved to be of poor diagnostic significance. For a full review of Tandonia ’s taxonomy see Wiktor 1987a: 165. Past authors who have dealt with the Western Balkan Tandonia , described new Dalmatian endemic species but provided only unclear or scant descriptions, without iconography and also often including errors and artefacts (cfr. Wiktor, 1996: 45): the description of T. reuleauxi by Clessin (1887: 46) was mainly based upon shell features; T. montenegrina was unclearly described by Simroth (1900: 107) as also stated by Wiktor (1996: 38). Simroth (1900: 106) also provided a brief description of the genitalia and the body of T. dalmatina , but it’s status still remains unclear (Wiktor 1996: 31). Nevertheless Simroth’s description of T. cavicola (1916: 4) was more complete, including both genitalia and body features and drawings, this iconography turns out to be too synthetic and lacking important taxonomic details. Wagner (1929: 333) Ecol. Mont., 1 (2), 2014, 123-130 NEW TANDONIA FROM THE ISLAND OF BRA Č described T. croatica only by its exterior appearance. In the same paper (Wagner 1929: 331) he also provided a full genital description for T. fejervaryi , allowing an easier systematics overview for this latter species. T. jablanacensis (Wagner, 1930) was fully described with both genitalia and body features, although never found again even after further field surveys (Wiktor 1987a, 1996). Once more, the description of T. lagostana (Wagner 1940: 138) was incomplete and scant, probably based upon juvenile specimens. As a consequence many species classified within the genus Tandonia still have an uncertain systematic position (Wiktor 1987a, 1996). Only in more recent times has the description of a new endemic Tandonia species fully matched all the taxonomics requirements for an effective systematic evaluation. Wiktor (1996: 39) introduced T. rara from mid-Dalmatia, providing accurate descriptions and drawings, although he overlooked some remarkable taxonomical feature (De Mattia, personal unpublished data). Recent collecting undertaken on the island of Bra č (Splitsko- Dalmatinska županija, Croatia) has provided a single, fully grown specimen of a totally black slug, belonging to the genus Tandonia . A careful investigation evaluating the genital anatomy and body traits, revealed a set of characteristic and unique taxonomic features which have never been previously observed in other representatives of the genus. By virtue of such results a new species, Tandonia bolensis, has been described. Table 1. Distribution of the Tandonia species living along the Western Balkans with references to the literature’s iconography. References (iconography) Distribution Wiktor, 1987a: 230 (body, whole genitalia, penial papilla, T. budapestensis (Hazay, 1881) Istria spermatophore) Simroth, 1916: 4 (body, whole genitalia, inner of penis-epiphallus); Dalmatia, Montenegrin T. cavicola (Simroth, 1916) Wiktor, 1987a: 234 (body, distal genitalia, inner structure of penial coast complex, penial papilla ) ? T. croatica (Wagner, 1929) Wagner, 1929: 333 (body); Wiktor, 1987a: 244 (no iconography) Dalmatia Simroth, 1900: 106 (no iconography); Wiktor, 1987a: 245 (no T. dalmatina (Simroth, 1900) Dalmatia iconography) Wagner, 1829: 331 (body, whole genitalia); Wiktor, 1987a: 247 T. fejervaryi (Wagner, 1829) (body, whole genitalia, distal genitalia, inner structure of distal Dalmatia genitalia, spermatophore); Wiktor, 1987b: 89 (spermatophore) T. jablanacensis (Wagner, Wagner, 1930: 46 (body, whole genitalia, sole); Wiktor, 1987a: Dalmatia 1930) 251 (body, whole genitalia) Wagner, 1940: 138 (body, whole genitalia); Wiktor, 1987a: 260 Dalmatia, Montenegrin ? T. lagostana (Wagner, 1940) (body, whole genitalia); Telebak et al., 2013: 62 (whole genitalia) coast ? T. montenegrina (Simroth, Simroth, 1900: 107 (no iconography); Wiktor, 1987a: 268 (no Montenegrin coast 1900) iconography) T. rara Wiktor, 1996 Wiktor, 1996: 39 (body, distal genitalia, inner structure of atrium) Dalmatia Clessin, 1887: 46 (no iconography). Wiktor, 1987a: 278 (body, T. reuleauxi (Clessin, 1887) whole genitalia, inner structure of distal genitalia, spermatophore); Dalmatia Wiktor, 1987b: 89 (spermatophore) Simroth, 1885: 230 (body). Wiktor, 1987a: 283 (body, complete T. robici (Simroth, 1885) Istria genitalia, inner of distal genitalia, papilla penis, spermatophore) T. rustica (Millet, 1843) Wiktor, 1987a: 286 (body, whole genitalia, penial papilla) Istria Wiktor, 1987a: 300 (body, distal genitalia, inner structure of distal T. sowerbyi (Férussac, 1823) Istria, Dalmatia genitalia, spermatophore) 124 DE MATTIA & NARDI Material and Methods The slug was drowned in water and then fixed in 80% ethanol. The shell was removed from its pocket beneath the mantle and the body was dissected under a Leica stereoscope. Anatomical details were photographed using a digital camera and later, freehand drawings were created from the photos. The shell and the body (including the jaw) was depicted and measured. The holotype is deposited in the Malacological Collection of the Museum and Art Gallery of the Northern Territory (NTM), Darwin, Australia. The following abbreviations are used for the anatomical parts: A atrium; AG albumen gland; AAG accessory atrial glands; BC bursa copulatrix; DBC duct of bursa copulatrix; DRC double ringed collar; E epiphallus; FD fleshy disk; FO free oviduct; G gonad; NLP nipple-like papilla; OS ovispermiduct: P penis; PP penial papilla; T talon; V vagina; VD vas deferens. Systematics Family Milacidae Genus Tandonia Lessona & Pollonera, 1882 Tandonia bolensis new species (Figs. 1-10) Types. Holotype from the type locality; no paratypes exist. Type locality. Limestone cliffs approximately 4 km E of Bol, along the road Bol-Sumartin, Bra č island, (Splitsko-Dalmatinska županija, Croatia), 43°16'2.22"N, 16°41'27.65"E, 305 m asl, G. Nardi leg., 30.vi.2014, deposited in the NTM, registration number: P. 54284. Diagnosis. Tandonia bolensis sp. n. is easily distinguishable from other Tandonia species by the dummy-like penial-atrial papilla, and the partially spiral-convoluted, thorny spermatophore. Figures 1-2. Body (after fixation) of Tandonia bolensis new species from Bol, Bra č island, Croatia. 1 lateral view; 2 foot sole. Scale bar: 1 cm. Ecol. Mont., 1 (3), 2014, 123-130 125 NEW TANDONIA FROM THE ISLAND OF BRA Č Figures 3-10 . Genitalia and shell of Tandonia bolensis new species from Bol, Bra č island, Croatia. 3 whole genitalia, gonad included; 4 distal genitalia; 5 inner structure of penial complex; 6 spermatophore; 7 magnification of the head of spermatophore; 8 magnification of the coiled central section of spermatophore; 9 shell; 10 talon. Scale bars: 1 mm. 126 DE MATTIA & NARDI Shell (Fig. 9). The shell is whitish, sturdy and thick in the midpoint, overall hyaline, and peripherally thin and transparent. It is located in a small pocket beneath the posterior part of the mantle (clipeus). It is slightly elongated, dorsally convex and only slightly concave ventrally. From its rear embryonic part, many irregularly spaced growth lines develop frontward, almost concentrically. These growth lines are much more visible on the dorsal