All scorpions collected from the islands of Malta, Gozo, Camino and St. Paul's belonged to Euscorpius (s.str.) carpathicus (linnaeus, 1773) ssp. candiota Birula, 1903 as used by Kinzelbach (1975) for populations showing a complex of morphological characters intermediate between E.carpathicus carpathicus and E.mesotrichus Hadzi. Similar intermediate populations are found in several eastern Mediterranean localities (Greece, some Greek islands and Crete)" however the Maltese populations are more heterogenous than any other so far studied. The literature contains records of other species of scorpion from the Maltese Islands whereas the collections of the British Museum (Natural History), London include specimens of Mesobuthus gibbosus (Brulle) reportedly collected from Malta. These records are discussed and it is postulated that they are either errors of identification or labelling, or else represent introduced exotics now locally extinct.peer-reviewe

Schembri, Patrick J.

Schembri, Stephen P.

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The Central Mediterranean Naturalist, Vol. 2 (1) - 1990 A NOTE CONCERNING THE SCORPIONS (ARACHNIDA: SCORPIONES) OF THE MALTESE ISLANDS (CENTRAL MEDITERRANEAN) Patrick J. Schembri 1 and Stephen Schembri 2 ABSTRACT All scorpions collected from the islands of Malta, Gozo, Camino and St. Paul's belonged to Euscorpius (s.str.) carpathicus (linnaeus, 1773) ssp. candiota Birula, 1903 as used by Kinzelbach (1975) for populations showing a complex of morphological characters intermediate between E.carpathicus carpathicus and E.mesotrichus Hadzi. Similar intermediate populations are found in several eastern Mediterranean localities (Greece, some Greek islands and Crete)" however the Maltese populations are more heterogenous than any other so far studied. The literature contains records of other species of scorpion from the Maltese Islands whereas the collections of the British Museum (Natural History), London include specimens of Mesobuthus gibbosus (Brulle) reportedly collected from Malta. These records are discussed and it is postulated that they are either errors of identification or labelling, or else represent introduced exotics now locally extinct. INTRODUCTION It has long been known that scorpions occur in the Maltese Islands; in fact, the Maltese language has three different terms for these animals: Gnakreb (Serracino-Inglott, 1976 p.153), and Mqass or Imqass (Serracino-Inglott, 1979 pp. 206-207), (literally meaning 'scissors', an obvious reference to the pincers), both derived from the Arabic, and the more recent Skorpjun (Serracino-Inglott, 1984 p. 194), derived from the Italian. Uncertainty however exists as to the number of species which occur and their specific identity. Gulia (1889-90) in his list of the Maltese names of local flora and fauna records under "Imkass" (an old form of the word Mqass), Scorpio europaeus as the only species and repeats this record in his later survey of the Maltese fauna (Gulia, 1913) . Cremona (1966) in his unpublished compilation of Maltese technical terminology gives "Imqass or Gnakreb var. spec. (Borg) (a) (Butus scorpio europaus) rare (b) (Euscorpio flavicandis) frequent (c) (Euscorpio italicus) common". The "Borg" in this entry refers to Professor John Borg, a medical doctor, botanist and horticulturist who occupied the Chair of Natural History at the University of Malta between 1921 and 1933, and from whom Cremona obtained his information. Apart from occasional generic mentions of scorpions in the popular and semipopular literature (e.g. Lanfranco, 1954; Coke, 1969), no other specific records of scorpions from the Maltese Islands exist. However, in his map oft he circum mediterranean distribution of scorpions of the family Buthidae, Kinzelbach (1975, legend to Fig. 6) states "Auf Malta lebt ein noch unbestimmter Vertreterder Buthidae"(a species of Buthidae living in Maltais not yet determined). Department of Biology, The University of Malta, Msida, Malta 2. National Museum of Natural History, Vilhena Palace, Mdina, Malta. 15 The literature therefore contains records of at least three different species of scorpions from the Maltese Islands as follows: Buthus occitanus (Amoreux, 1789) - the "Scorpio europaeus" of Gulia (1889-90, 1913) and the "Butus scorpio europaus" of Borg (in Cremona, 1966); Euscorpius (Polytrichobothrius) flavicaudis (De Greer, 1778) - the "Euscorpio flavicandis n of Borg (in Cremona, 1966); Euscorpius (Polytrichobothrius) italicus (Herbst, 1800) - the "Euscorpio italicus n of Borg (in Cremona, 1966); additionally there is the unidentified buthid mentioned by Kinzelbach (1975). However, the present authors have only ever met with a single species of Euscorpius in the Maltese Islands. The problem of the number of Maltese species and their identity was therefore investigated. MATERIAL AND METHODS Scorpions were collected from various localities in the Maltese Islands by systematically searching likely habitats. Specimens were killed and fixed in 70% ethanol. Measurements were taken using vernier calipers while counts of the number of pectine teeth and of trichobothria were made using a stereomicroscope. Additional to these field and laboratory investigations, attempts were made to trace specimens of scorpions collected from the Maltese Islands in a number of public and private collections. RESULTS Specimens of scorpions from the Maltese Islands were traced in two local private collections and in the collections of the British Museum (Natural History), London (BMNH). The collection of Guido Lanfranco (Sliema, Malta) contains specimens collected from Malta between August 1953 and October 1954 and identified as Euscorpius carpathicus (L.) by G. Owen Evans of the BMNH in 1956 (G. Lanfranco, personal communication 1987). The collection of Edwin Lanfranco (also of Sliema, Malta) contains a specimen collected from a house in Sliema in 1970 and identified as E.carpathicus by D.J. Clark of the BMNH in 1970 (E. Lanfranco, personal communication 1987). The only material from the Maltes~ Islands in the collections of the BMNH are two specimens of a buthid scorpion tabelled as collected on Malta by G.L. Clarke; no precise locality or date of collection are indicated although the latter is probably between 1920-1930 (P.O. Hillyard, personal communication 1986). These two specimens were identified as Mesobuthus gibbosus (Brulle) by R. Kinzelbach in 1984 (R. Kinzelbach, personal communication 1984). A total of 68 specimens were collected from various localities in the Maltese Archipelago during the present study as detailed below: 16 • MALTA 1 spec. Siggiewi 6.2.77 leg. PJS (SS/RKl01) and 1 spec. 5.7.88 leg_ M. Pace (SSIRKl28); 1 spec. Birkirkara 9.11.77 leg PJS (SSIRKl02); 1 spec. Selmun 20.12.79 leg. PJS (SS/RKl03); 1 spec. Gliadira 27.12.79 leg. SS (SS/RKl04); 1 spec. Dingli Cliffs 3.11.82 leg. PJS (SS/RKl05); 1 spec. Tal-Kortin (Mistra) 18.3.84 leg. PJS (SS/RKl06); 1 spec. Wied Incita 25.3.84 leg. SS (SS/RKl07); 4 spec. Ballut ta'l-lmgiebali 8.4.84 leg. SS & PJS (SS/RKl08); and 3 spec. 11.1 0.86 leg. PJS & D.M. Johnson (SS/RKI24); 6 spec. Balluttal-Wardija 8.4.84 leg. SS& PJS (SS/RKl09); 3. spec. Tal-Qroqq (University grounds) 16.4.84 leg. S. Azzopardi & L. Main (SSIRKl1 0); 2 spec. Wied il-Luq (Buskett) 30.4.84 leg. SS & PJS (SSIRKl11); 4 spec. Beltissebli (Florian a Bastions) 6.5.84 leg. PJS & M. Gauci (SSIRKl12); 1 spec. Santa Venera 30.5.84 leg. PJS (SS/RKl13); 1 spec. Bingemma Gap 30.3.85 leg. SS (SS/RKl14); 1 spec. Ta' Zammitello (Gnejna Bay) 12.10.85 leg. D.M. Johnson (SSIRKl15); 1 spec. Birkirkara (Psaila Street) 25.10.86 (SS/RKI25); 2 spec. (no date) (SS/RKI26); and 1 spec. 31.10.87 (SS/RKI27) all leg. D. Galdes Giappone; 6 spec. Malta & Gozo Sept 1985 - Mar. 1986 leg. SS & D.M. Johnson (SS/RKl23); GOZO 5 spec. Dwejra 17.5.84 leg. SS (SS/RKl17); 6 spec. Fort Chambray slopes 3.2.85 leg. PJS & M. Gauci (SS/RKl18); 6 spec. Limits of Kercem 14.2.85 leg. PJS (SS/RKl19); 2 spec. Ramla (clay slopes) 15.2.85 leg. PJS (SS/RKl20); COMINO 1 spec. Comino 23.6.75 leg. PJS (SSIRKI21); and 3 spec. 22.6.86 leg. SS (SS/RKl22); ST. PAUL'S ISLANDS 2 spec. St. Paul's Islands 20.4.75 leg. PJS (SS/RKl16). In general scorpions occurred in three main habitat types: (i) the leaf litter which accumulates underneath trees (e.g. Holm Oak, Quercus ilex) and low-growing shrubs (e.g. Carob, Ceratonia siliqua); (ii) under stones on clay slopes; and (iii) in association with human habitations, especially in humid microhabitats (e.g. drains, cellars, underneath flowerpots etc); a few specimens also occurred under deeply embedded stones in garigue. Specimens with reference numbers SS/RKl01 to 25 were sent to Professor Ragnar Kinzelbach of the Institut fur Zoologie, Technische Hochschule Darmstadt for examination and were all identified as Euscorpius (s.str.) carpathicus (Linnaeus, 1773) ssp. candiota Birula, 1903. Two specimens from the series SS/RKl09 have been deposited in the Kinzelbach collection; all other specimens are in the collection.of PJS. For each specimen, the following parameters were determined: Length of the chela of the pedipalp measured from the tip of the fixed finger to the posterior edge (Ch); 17 Prosoma length measured from the anterior to the posterior border (Pr); The number of pectine teeth (PT); The number of trichobothria on the ventral edge of the tibia of the pedipalp (TPT; see Kinzelbach, 1975). Chela length and prosoma length are highly positively correlated (Pearson product-moment correlation: r=0.982, d.f.=64, P <0.001); the regression equation is: Ch = 0.575 + 1.678 Pr; Either Ch or Pr can thus be used as an index of size and hence age. Scorpions may be sexed on the basis of size and the number of pectine teeth: males have more pectine teeth than females and are smaller (Millot & Vachon, 1949). Kinzelbach gives the following pectine teeth formula for E.carpathicus: males 7-10, females 6-9. Of the 66 specimens measured, 20 (30.3%) had an unequal number of teeth on the two arms of the pectine. For these, the average value was taken (PT left + PT right /2). The correlation between PT and prosoma length is not significant (Pearson product-moment correlation: r=-0.0378, d.f.=64, 0.5<P), showing that PT does not increase with size/age. The frequency distribution of PT (Fig.1) shows two main peaks, one centred on PT =7 and the other on PT =8. To test whether these two peaks represent the different sexes, the mean prosoma length for adult individuals (Le. with Pr> 2.00mm, see below) with a PTof 7 or less (n=24, x=4.74mm, s.d.=0.80mm) was compared with that for those with a PT of 7.5 or more (n=28, )(=4.41 mm, s.d= 1.1 Omm); the difference was not significant (Student's Hest: t= 1.226,0.2 <P<0.5). The Maltese scorpions, therefore, cannot be sexed on the basis of number of pectine teeth and size by this method. Reliable counts of TPT could not be made for individuals of Pr -:<2.00mm, of which there were 14 in the sample. These were obviously juveniles. Of the remaining 52 adult specimens, 22 (42.3%) had an unequal TPTon the two pedipalps. For these individuals, the average TPT was calulated (TPT left + TPT right /2). The correlation between TPT and prosoma length is not significant (Pearson product-moment correlation: r=-0.0217, d.f.=50, 0.5 <P); TPT does not increase with the size/age ofthe individual. Forthe sample considered as a whole, the mean TPT is 9.44 (s.d. =0.844, n=52). however the TPT frequency distribution (Fig. 2) shows two main peaks, one (the larger) at TPT =9 (30.8% of the sample) and the other at TPT =10 (25.0% of the sample). DISCUSSION With the sale exception of the two specimens in the collections of the BMNH, all scorpions collected from the Maltese Islands belong to the same taxon, identified as Euscorpius (s.str.) carpathicus (Linnaeus, 1773) (family Chactidae) by all specialists in the group who have examined Maltese material. The two BMNH specimens have been identified as Mesobuthus gibbosus (Brulle, 1832) (family Buthidae), a species whose recorded range is Greece, Cyprus and Asia Minor (see map in Kinzelbach, 1975 p.22). One explanation 18 • .. for the apparently anomalous record of this species from the Maltese Islands is that the species was introduced, possibly through human agency, and subsequently became locally extinct. Another explanation is that the BMNH specimens are mislabelled and did not originate from the Maltese Islands at all. Gulia's (1889-90; 1913) record of Scorpio europaeus (=Buthus occitanus) is most likely a misidentifcation and refers to Euscorpius carpathicus, especially since Gulia mentions no other species of scorpions from the Maltese Islands. Similarly, Borg's (in Cremona, 1966) records of Euscorpius flavicaudis and Euscorpius italicus probably refer to different forms within the range of variation of the local population of Euscorpius carpathicus. Borg's record of "Butus scorpio europaus" (=Buthus occitanus) is intriguing since Borg could obviously differentiate between Buthus and Euscorpius. It is possible that Borg never actually encountered specimens of Buthus but accepted previous records (e.g. Gulia's) at face value. Alternatively, Borg's Buthus may be an introduced exotic, now extinct from the Maltese Islands. It is worth noting that Professor John Borg was very active at the Argotti Botanical Gardens, then belonging to the University of Malta and also at San Anton Gardens where he was Principal of the Agricultural School for Gardeners (Borg, 1979) and was constantly receiving plant material from abroad. It is also possible that Borg's 'Buthus' and the Mesobuthusgibbosus collected by G.L. Clarke in Malta and now at the BMNH represent the same introduced exotic; certainly the period over which Borg was active (c1895 to 1933) and the probable date of collection of Clarke's specimens (c. 1920-1930) overlap. 25 r0-20 I-I--5 -o c--r--r--r--~ n 5-5 6 6-5 7 7-5 6 Number of pectine teeth r--6-5 Fig. 1 Frequency distribution of the number of pectine teeth for Euscorpius carpathicus from the Maltese Islands. 20 >. u C OJ ~ rr QJ '-15 u...10 19 5 O~~~~~~W-~~~LLJ-~~~ 7-5 6 8-5 9 9-5 10 10-5 11 11-5 12 TPT Fig. 2 Frequency distribution of the number of trlchobothrla on the ventral edge of the tibia of the pedipalp (TPT) for Euscorpius carpathicus from the Maltese Islands. On the basis of his studies of the Aegean scorpions, Kinzelbach (1975) split the Euscorpius carpathicus of older authors into two species: Ecarpathicus s.str. and E mesotrichus Hadzi. These two species are distinguished by a number of characters (see Kinzelbach, 1975 Table 2), chief among which is the number of trichobothria on the ventral edge of the tibia of the pedipalp (TPT); Ecarpathicus has TPT = (6)7-8(9) Emesotrichus has TPT=10-12(14) (extremes in parentheses). Populations intermediate between carpa-thicus and mesotrichus occur in several localities in Greece and on the island of Crete. These intermediate forms are characterized by a TPT of 9-10, a reddish brown coloration without a distinct pattern in black pigment, and by the relative smoothness of the edges of the chelae. A name already being available for forms showing this complex of characters, Kinzelbach (1975) assigned these intermediate forms to E.carpathicus candiota (Birula). Kinzelbach is of the opinion that the Maltese populations also belong to this entity. We concur with this view. The majority of specimens studied by us had a TPT in the range 9-10, however, there is also considerable variation; 17.3% of the specimens examined had a TPT of less than 9, which is in the range of Ecarpathicus carpathicus, while 13.5% had a TPT of more than 10, which is in the range of Emesotrichus. In this respect, the extreme forms are of particular interest: at the lower end, one specimen (SSIRKl11) had a TPT formula of 7:8 while at the upper end four individuals had a TPT formula of 10:11 (SS/RKl15,21 ,23), two of 10:12 (SS/RKl22,23) and one of 11:13 (SS/RKl23); The Maltese candiota population seems to be more heterogeneous than other candiota populations so far studied; for example, populations from Kefallinia and Crete both had a TPT range of 8-11 (see Kinzelbach, 1975 Fig. 13). In any case, the presence of a mixed carpathicuslmesotrichus population in the Maltese Islands similar to those on Greece, Crete and small Aegean islands, links the Maltese Islands faunistically with the Eastern Mediterranean. Ecarpathicus candiota is found on all three main islands of the Maltese Archipelago as well as on one of the minor islets of the group, and is common where found. On the whole it appears to prefer dark humid habitats (e.g.leaflitter, human habitations) although it also occurs in more arid habitats such as garigue and clay slopes. On the latter, scorpions are particularly abundant, sometimes as many as five individuals being found under a single stone covering an area of only a few tens of square centimetres. However, in both garigue and clay slopes, scorpions may actually be occupying relatively humid microhabitats since the soil under embedded stones retains some moisture even during the very dry Maltese summer, particularly if it is clayey. ACKNOWLEDGEMENTS We are very grateful to Professor Dr Ragnar Kinzelbach for studying our collection of scorpions and for supplying us with much useful information and for other help. We are grateful also to Dr. Paul D. Hillyard of the British Museum (Natural History) for information about the specimens in his care, and to Messrs Guido and Edwin Lanfranco for information about specimens in their collections. We thank Ms Joan Anne Farrugia for her technical assistance, Mrs Moira Schembri for help with translation from the German and all those who supplied us with specimens. REFERENCES BORG, J. (1979) The public gardens and groves of Malta and Gozo. Malta: Men of the Trees (Malta); 147 pp. 20 COKE, P. (1969) Teaching science in Malta. Malta: Department of Information, 91 pp. CREMONA, A. (1966) Maltese technical terminology, Vol. II: Entomological, ornitho-log; cal and ichthyological Maltese terms with their English and Italian equivalents. Unpublished typescript in the Melitensia Collection of the University of Malta Library. GUllA, G. (1889-90) Prontuario di storia naturale contenente la nomenclatura scientifica coi corrispondenti vocaboli italiani ed inglesi degli animali e delle piante che sono conosciuti sotto una denominazione maltese. Malta: A. Puglisevich, 71 pp. GUllA, G. (1913) Uno sguardo alia zoologia delle 'Isole Maltesi'. IX Congres International de Zoologie, Monaco 1913 sect. 4: 545-555. KINZELBACH, R. (1975) Die Skorpione der Agais: Beitrage zur Systematik, Phylogenie und Biogeographie. Zool. Jb Syst. 102: 12-50. LAN FRANCO, G. (1954) Friends and foes in our homes. Times of Malta, June 29. MILLOT, J. and VACHON, M. (1949) Ordre des scorpions. In: Grasse, P.P. (ed.) Traite de zoologie Vol. 6 pp. 386-436; Paris Masson et Oa SERRACINO-INGLOTT, E. (1976, 1979,1984) II-Miklem Malti. Vol. /1/ (1976), Vol. VI (1979), Vol. VIII (1984); Malta: Klabb Kotba Maltin. Received August 1988. ADDITIONAL NOTE During recent surveys of the Filfla Island Nature Reserve conducted jointly by the Department of Biology of the University of Malta, and the Secretariat for the Environment of the Ministry of Education and the Interior, two specimens of scorpions were collected and are reported upon below: 1 spec. Filfla Island (plateau) 23.2.90: Ch = 11.30 mm: Pr = 6.00 mm: PT (left/right) = 7/8; TPT (left/right) = 10/9 . 1 spec. Filfla Island (plateau) 13.3.90: Ch = 6.20 mm: Pr = 4.30 mm; PT (left/right) = 717; TPT (left/right) = 9/8. Both specimens were found under stones embedded in soil. The Filfla scorpions correspond well with E. carpathicus candiota as defined by Kinzelbach (1975). It is interesting that the scorpions of Filfla are not different from those of the other islands of the Maltese group as Filfla is the most outlying island of the archipelago and one of the most inaccessible and least visited. This suggests that the Maltese candiota populations were not introduced through human agency. Received December 1990 21 

A note concerning the scorpions (Arachnida : Scorpiones) of the Maltese Islands (Central Mediterranean)

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A note concerning the scorpions (Arachnida : Scorpiones) of the Maltese Islands (Central Mediterranean)

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