Presence of Discus Rotundatus (Gastropoda, Endodontidae) on the Island of Mallorca

Miscel.lania Zooloqica 19.1 (1996) 51

Presence of Discus rotundatus (Gastropoda, Endodontidae) on the island of Mallorca

Altaba, C. R., 1996. Presence of Discus rotundatus (Gastropoda, Endodontidae) on the island of Mallorca. Misc. ZooL. 19.1: 51-54.

Presence of Discus rotu ndatus (Gastropoda, Endodontidae) un the island of Mallorca.- The finding of shells of Discus (Gonyodiscus) rotundatus (O. F. Müller, 1774) among flood debris in North-eastern Mallorca represents the first record of the species in the Balearic islands. Its presence is probably due to human introduction together with plants and soil.

Key words: Snails, Western Mediterranean, Mallorca, Islands, Dkcus rotundatus, Endodontidae.

(Rebut: 6 VI1 95; Acceptació condicional: 22 XI 95; Acc. definitiva: 20 11 96)

Crktian R. Altaba, lnst. Mediterrani dfEstudis Avancats (CSIC-U/@, ctra. de Valldemossa km 7,5, 07071 Palma de Mallorca (//les Balears), Espanya (Spain).

This work was supported by project PB93-0055 of DGICYT.

lntroduction 1980), but has received little attention by zoologists. The location in this re- The terrestrial molluscan fauna of the gion of a previously unrecorded species Balearic lslands is relatively well known in the Balearic islands is presented. (GASULL,1966; ALTABA,1991), although there are still insufficiently explored zones and several taxonomic problems (ALTABA, Material and Methods 1993). The Arta peninsula, at the North- eastern tip of Mallorca, is known for its During a campaign to collect terrestrial floristic uniqueness (e.g. BONAFÉ,1977- and freshwater moiiuscs in this area, a

@ 1996 Museu de Zoologia sample of alluvial detritus was collected tid with a characteristic shell, living in on 19 IV 1995 at the banks of Torrent shady or damp habitats. The collected de Canyamel (UTM 31T ED 3592, altitude material includes six shells (three juve- 45 m). This is a temporary stream, fed nile). Voucher specimens have been de- by many springs and by runoff from most posited in the malacological collections of the Arta Region (fig. 1). of the Museu de la Naturalesa de les The alluvial detritus were washed and llles Balears (MNCM 91 1) and the Museu a large number of gastropod shells were de Zoologia de Barcelona (MZB 96- separated manually. These shells had been 01 51). The remaining specimens are kept carried by the water current from sites lo- in the author's collection (CRA-6029). cated further upstream. Thus, they repre- This represents the first known finding sent a semi-quantitative sample of the mol- of Discus rotundatusin the Balearic islands. lusc fauna of the drained watershed. The On the beaches of Menorca, Gnsu~~(1965, complete list of the species found will be 1966) found stranded shells of this spe- published elsewhere (ALTABA,in press). cies. According to this author, these shells would have arrived floating frorn the con- tinent along with marine currents. The Results and Discussion presence of this species in the closest region of the neighbouring island of Ma- One of the most interesting species col- llorca allows to assume a less distant ori- lected is Discus (Gonyodiscus) rotundatus gin for the shells brought to the Menorcan (O. F. Müller, 1776). This is an endodon- shore. Miscel.lania Zoologica 19.1 (1996) 53

Flg. 1. Gewrclphicol distribuJZan 04 Dhcus rotundatus in Eurbps &&d Éhr!

DlS&W&n gckr@griSfEcr de D1xw re"U~l(Sr?ifu~en Europa y el Medkc?%s%m..

The geographical distribution of this North and East of Europe, Madeira, snail (fig. 2) extends through rnost of Eu- North-eastern North Arnerica, and Cali- rope, the Acores and the Maghrib (FORCART,fornia (JACOBSON& EMERSON, 1971; RIEDEL 1965; RIEDEL& WIKTOR,1974; BACKHUYS,1975; & WIKTOR,1974; ROTH, 1982). The only KERNEY& CAMERON, 1979; BECKMANN,1987; known instance of Discus rotundatus not ALTABA,1991), including the northern third succeeding to establish after being in- of the lberian peninsula (ALTONAGA,1989a, troduced is in Malta, where it was found 1989b; ALTONAGAet al., 1994) and the in a garden (THAKE,1984), but later Mediterranean islands of Corsica, Sardinia, searches have not detected it anywhere Elba, Giglio, Gorgona, Montecristo, Capri, on the Maltese archipelago (BECKMANN, Lipari, Salina, and Sicily (ALZONA,1971; 1987). The presence of this species in RIEDEL & WIKTOR,1974; REAL& REAL-TESTUD,Mediterranean insular environrnents ap- 1988; PIANTELLIet al., 1990). pears to fit the biogeographic rnodel pro- The origin of the Mallorcan population posed to explain the distribution of non- probably lies in an involuntary anthropic autoctonous species. According to this introduction. These are tiny anirnals that rnodel, an initial phase of casual intro- burrow in the soil, thus being prone to duction and colonization is followed by transportation along with plant material. local extinction, or by establishment and Indeed, established populations have been expansion (PIANTELLIet al., 1990; ALTABA, found in hurnanized environrnents in the 1993). 54 Altaba

Resumen ALZONA, C., 1971. Malacofauna italica. Catalogo e bibliografia de¡ Presencia de Discus rotundatus (Gastro- molluschi viventi, terrestri e d'acqua poda, Endodontidae) en la isla de Ma- dolce. Atti Soc. ital. Sci. nat. Mus. civ. llorca Stor. nat. Milano, 111: 1-433. BACKHUYS,W., 1975. Land and freshwa- El hallazgo de conchas de Discus ter molluscs of the Azores. Backhuys (Gonyodiscus) rotundatus (O. F. Mül ler, & Meesters, Amsterdam. 1774) entre aluviones en el nordeste de BECKMANN,K.-H., 1987. Land- und Süsswa- Mallorca (fig. 1) representa la primera cita ssermollusken der Maltesischen Inseln. the esta especie en las islas Baleares (fig. Heldia, 1: 1-38, tf. 1-5. 2). Su presencia es debida probablemente BONAFÉ,F., 1977-1980. Flora de Mallorca. a la introducción por el hombre junto con 4 vols. Ed. Moll, Palma de Mallorca. plantas y tierra. FORCART,L., 1965. Rezente Land- und Süss- wassermollusken der süditalienischen Landschaften Apulien, Basilicata und Acknowledgements Cala brien. Verhandl. Naturf. Ges. Basel, 76: 59-184. My wife Catalina Ponsell Vicens collabo- GASULL,L., 1965. Algunos moluscos te- rated in the mollusc collecting campaign rrestres y de agua dulce de las Balea- in the Arta Region. res. Bol. Soc. Hist. Nat. Baleares, 11: 7-161. - 1966. La insularidad de las Islas Baleares References desde el punto de vista de la mala- cología terrestre. Bol. Soc. Hist. Nat. ALTABA,C. R., 1991. MOIIUSCS.In: Historia Baleares, 12: 149-156. Natural dels PaiSos Catalans, vol. 8: JACOBSON, M. K. & EMERSON, W. K., 1971. lnvertebrats no artropodes: 375-41 6, Shells from Cape Cod to Cape May, 427-470 (C. R. Altaba, Ed.). Enciclopedia with special reference to the New Catalana, Barcelona. York City afea. Dover Publ., New York. - 1993. Els caragols i llimacs (Mollusca: KERNEY,M. P. & CAMERON,R. A. D., 1979. A Gastropoda) de I'Arxipelag de Cabrera. field guide to the land snails of Britain In: Historia natural de I'Arxipelag de and North-west Europe. Collins, London. Cabrera: 409-426 (J. A. Alcover, J. PIANTELLI,F., GIUSTI, F., BERNINI,F. & Fornós & E. Ballesteros, Eds.). Ed. Moll MANGANELLI,G., 1990. The mollusc and & C.S.I.C., Palma de Mallorca. oribatid fauna of the Aeolian and - (in press.). Mol.luscs recollits en els Tuscan archipelagos and the island al.luvions del Torrent de Canyamel equili brium theory. Atti Convegni Lincei, (Mallorca). Boll. Soc. Hist. Nat. Balears. 85: 117-1 54. ALTONAGA,K., 1989a. Discus rotundatus REAL,G. & REAL-TESTUD,A.-M., 1988. La (O. F. Müller 1774) (Pulmonata: malacofaune terrestre de I'ile de Corse: Endodontidae) marraskiloa lberiar historique et inventaire actuali- Penintsulan. Elhuyar, 15: 24-52. sé. Haliotis, 18: 43-54. - 1989b. La familia Endodontidae Pilsbry RIEDEL,A. & WIKTOR,A., 1974. Arionacea 1894 (Pulmonata: Stylommatophora) en - Slimaki krazalkowate i slinikowate la Península Ibérica. Kobie (Ser. Cienc. (Gastropoda: Stylommatophora). Fauna Nat.), 18: 123-136. Polski, 2: 1-140. ALTONAGA,K., G~MEZ,B., MARTIN,R., PRIETO, ROTH, B., 1982. Discus rotundatus C. E., PUENTE,A. & RALLO,A. 1994. Estudio (Gastropoda: Pulmonata) in California, faunístico y biogeográfico de los moluscos USA. Malacol. Rev., 15: 139-140. terrestres del norte de la Península THAKE,M., 1984. New record of land snails Ibérica. Eusko Legebiltzarra, Vitoria- inhabiting leaf litter from the Maltese Gazteiz. islands. Central Medit. Natu~,1 : 63-65.