Erpetologia delle isole circumsarde

Abstract

BIOGEOGRAPH/A - vol. XVIII « 1995 (Pubblicato II 31 ottobre 1996) Le piccole lsole Circumsarde e il Ioro significato Biogeografico Erpetologia delle isole circumsarde MARTA POGGESI, PAOLO AGNELLI, MARCO BORRI, CLAUDIA CORTI, PIER LUIGI FINOTELLO, BENEDETTO LAN ZA e GIANLUCA TOSINI Mureo dz‘ Storm Ncztumle (Sezioize Zoologiaz «La Specolcz») e Dipartz'772em‘0 di Biologzkz Aizimzzle e Geizetica, Um'versz‘t:? dz‘ Fireizze, via ROI7Z[llZ(l, 17 - 50125 Firezzze (I TALIA) In memorzkz cii Gz‘0vmmz‘Ce5cm1ccz'0 (La Maddalena 11.X. 1950 — 3. VIII. 1992), 0z‘tz'm0 mzz‘umZz'stzz, 0z‘tz'm0 amico. G12’ Autori. Key words: Amphibia, Reptilia, Sardinia, Distribution, Zoogeography. SUMMARY Out of the more than 160 Sardinian satellite islands, islets and rocks with a covering of vascular plants (Tables I-II), 116 have been surveyed for the presence of reptiles and amphibians (Table I). Their occurrence was verified in 102 of the satellite islands (Table III), a figure which will surely increase in the future; the tiny, nocturnal and cryptozoic gelckonid P/131110:/aclylz/I europaezzx, f. i., probably occurs on all or almost all Circumsardinian islands as it is able to survive even on extremely small, barren and semi-naked rocks. Among the water-linked batrachians, all the autochthonous Sardinian anurans, occur in the largest sui- table satellite islands (Dz'.\‘c0gZ0m2_t mrclzu‘, Hy/:1 mrda, Bzzfo I/mic/1's), while the rather recently naturalized Ra/zzz sinltlepton esculenta is lacking; the absence of the only Sardinian salamandrid, the endemic Ezzproctz/X plat)?- cep/Jalux, is surely due to ecological constraints. On the contrary the absence of the four terrestrial endemic salamanders Hydrama/zler flazms, H. _rup1m/20/Itix, H. iI2Iperz'z1lix and H. gezzei, even on the largest islands where they could very propably survive, seems to be due to zoogeographical reasons; in fact, up till now, all the coastal areas facing the above-mentioned islands are devoid of any members of the family Plethodontidae. There are 18 Sardinian species of reptiles, 16 of which occur on the satellite islands: Emy: ar[7z'czzlm'z'r ctzpolazzgai, Test:/do graezra grzzeca, Testz/do /Jer/71a/2/71' /Jerzzzmz/H’, Textudo Iizzzrgzmzta, Hemz'dzzclylzz.t Imricz/3', Tare/ztala /izamita/1z'cz1 ;7zazm'tzzIzz'ca, P/Jyllodactylm ez/ropaez1.r, /llgyroidex fz'lzz'/zgeri, Arc/Jrzeolacerta [2ezz’I'z'(1gzze pczessleri, Pat/zzrcir tzfigzzemz (with the «subspecies» /iliguerta, m/Izii and tom), Podarcis sicula (with the «sub- speciesgg cettii), C/Jalczkler c/Jzzlczkles vzflatm, C/mlczklex ocellzzlzzx tiligugu, Hemorr/Joir /Jz'ppocrepz'5, Hzerap/Jii‘ v1'r/dzflzzzzzzx, Natrix /zzazzra. The two missing specie are Nat/‘ix (Imtrix) rem which, as it is not as euryoecious as N. /mzzmz, probably does not find favourable environmental conditions even on the largest satellite islands, and Elap/ye lozzgisrima la/zgirsizrza, a species almost surely acclimatized in historical time and at present know to inhabit only a limited coastal areas of central western Sardinia (Mt. Ferru). Wortli mentioning is a trip account by Lilford (1875). a careful reading of which reveals that La Vacca Island (Tables I and III, No. 121; Fig. 1) was probably inhabited by a lacertid (P0dzzrcz'r I1’!/gz1e2'Iz1?) and surely by a relatively rich population, presently extremely reduced or even extinct, of the colubrid Hierop/J1‘: vim/zflavzrs. I Of the Circumsardinian islands inhabited by amphibians and/or reptiles, the oldest ones5'seem to be the islets Molarotto (Tables I and III, No. 85, Figs. 1-2), and I1 Toro (Tables I and III, No. 120, Fig. 1), which probably detached from Sardinia about 12,000 and 15,000 years ago respectively. They are the only ones to host vertebrates rather strongly differentiated, at least at a phenotypic level, with respect to those living on the main island: the llsubspeciesgg Paa'zzrci: tzfigzzertzz ranzii (Molarotto) and P I. taro (Toro). Pat/zzrcz'r .rz'cz/la, which almost surely populated Sardinia in prehistoric (protostoric?) times, introduced 583