LACERTILIA OF THE MALTESE ISLANDS

INTRODUCTION: The Maltese Lizards (sub-order LACERTILIA) number five species. The majority of species composing our lacertilian fauna probably date to the time when the Islands were connected to the european mainland via a landbridge. However, other species may have been imported either directly, as with Chamaleo chamaleon (Linn) which was imported and set free in a private garden around 1880, or alternatively may have been introduced by continual trade contact with the mainland.

IDENTIFICATION KEY TO THE MALTESE SPECIES
1a. - Head dorsum covered with small irregular or polygonal scales.............................2
1b. - Head dorsum covered with larger symmetrical arranged scales...........................4

2a. - Body rounded or slightly flattened dorsoventrally; digits not opposed, eyes cannot be closed................................................................................................................................3
2b. - Laterally flattened body; limbs with free digits, two opposed the other three; eyelids present and fused to leave minute opening...............................Chamaeleo chamaeleon

3a. - Digits slightly enlarged, all carrying a terminal claw. Lamellae on the underside of the digits are arranged in transverse double rows............................Hemidactylus turcicus
3b. - Digits greatly enlarged, of which only the third and fourth claw carry a claw. Lamellae on the underside of the digits are arranged transversally in a single series............................................................................................Tarentola mauritanica

4a. - Tail scales different from body scales. Ventral scales of body rectangular, dorsal scales rounded...................................................................................Podarcis filfolensis
4b. - Tail scales different from body scales. Ventral and dorsal scales of body of hexagonal shape...................................................................................Chalcides ocellatus tiligugu
 


SYSTEMIC IDENTIFICATION OF THE MALTESE LACERTILIAN SPECIES

 


Class: REPTILIA
Order: SQUAMATA
Sub-order: LACERTILIA
Family: CHAMALEONTIDAE
Chamaleo chamaleon (Linn)
European Chamaleon
maltese: Kamalejonte
Size: up to 30 cm long, including tail.
Colouration: Colour variable depending on various factors; usually grey-green with numerous small darker specks and two series of brown patches on the side; white stripe on belly.
Biological Notes: This lizard is arboreal, sluggish and feeds on a variety of arthropods including spiders, flies, cockroaches, grasshoppers and butterflies. In captivity one specimen also took lizards. It captures its prey by means of a sticky extensible tongue.
The Chameleon is not an indigenous species but was probably introduced in the 19th century and has subsequently become established and has spread. The Chameleon has few predators locally and is generally difficult to see - reasons for its success. The animal is oviparous, the female laying about forty eggs in spring which probably hatch in autumn.
Records: This species was first recorded by Giovanni Gulia in 1890. It was supposedly introduced by Jesuit priests at St. Julians (Gulia, 1890). While Gulia considered it to have become naturalised, Despott (1915) could not obtain any specimens and did not include it in his list of Maltese herpetofauna. There is now no doubt that the animal has established itself and spread. It is likely, however, that this spread has occurred from more than one locality. Recent records include numerous specimens from St. Julians, Paceville, Gzira, Sliema, Msida, Manoel Island, Naxxar, Gharghur, Lija, Birkirkara, Mosta, Selmun, Kalkara, Zabbar and Santa lucia. Specimens have also been captured from Xlendi and Xewkija in Gozo.


Family: GEKKONIDAE
Hemidactylus turcicus turcicus (Linn)
Turkish Gecko
maltese: Wizgha tad-djar
Size: Up to 12 cm. long (including tail).
Colouration: Dorsallu grey, reddish or light brown marbled with white; ventrally white. Has a limited capacity for colour change.
Biology: This animal is strictly nocturnal. It spends the day under rocks, fallen branches, etc. It was at one time common inside houses, hence its Maltese vernacular name, but now is rarely seen in this enviornment, probably because of relentless persecution. Along with the Wall Gecko, it was at one time falsely associated with the development of leprosy (Despott, 1915). The turkish Gecko feeds on a variety of insects and on spiders. It has a wide range of predators, including the Large Orb-Web Spider (Argiope lobata), the frog, the hedgehog, the weasel and snakes. Its defence appears to lie mainly in its easily lost tail. When distrubed the Gecko often runs with its tail raised well above the ground, as if offering this expendable part of its anatomy to its pursuer. The animal is oviparous, the female laying a pair of eggs in Summer. Development takes about three months.
records: This gecko is widely distributed in the Maltese Archipelago. It has been recorded from Malta, Gozo, Comino, Cominotto, St. Paul's Islands and Filfla.

Tarentola mauritanica mauritanica (Linn)
Wall Gecko
maltese: Wizgha tal-wiedien
Size: Up to 16 cm long (including tail).
Colouration: Dorsally grey or brown marbled with dark and light markings; ventrally white. There appears to be two main colour forms - a light and dark variety, but this is due probably to a limited ability to change colour.
Biology: Though this gecko forages for food at night, it may be observed sunning itself during daytime. It tends to frequent the same hunting grounds and may be found in the same place day after day. It feeds on moths, mosquitoes, spiders, etc. The adult, by virtue of its stregth and size, is a match for most predators but succumbs to the larger ones. Its defence also depends on its easily lost tail. The attacking animal is often left with a wriggling tail in its mouth while the gecko gets away safely. The tail is then regenerated, but if the old tail is incompletely detached a two-tailed condition may result Schembri, 1975). The Wall Gecko is oviparous laying its eggs in spring and summer. The eggs are hard-shelled and hatch after a period of four months.
Records: This species is widespread in the Maltese Archipelago, being recorded from Malta, Gozo, Comino, Cominotto and Filfla.

Family: LACERTIDAE
Lacerta filfolensis Bedriaga
Maltese Wall Lizard
maltese: Gremxula, Dorbi
Size: up to 25 cm long (includng tail)
Colouration: Dorsally brownish green with a variable amount of dark markings; ventrally bluish or yellowish white with again a variable amount of black markings. Various subspecies based on the degree of melanism have been described, though the exact taxonomical status of these forms is still uncertain.
Biology: The Wall Lizard lives in rock crevaces wgich are well exposed to the sun. During the day the lizards can be seen basking in the sun when not hunting. The animals have a very intimate knowledge of their individual home ranges. This knowledge, together with their agility and the ability to lose their tail, form the basis of their defence against predators. A lost tail will regenerate to a early exact replica of the former, though the two-tailed condition may also occur. Predators are various and include snakes, the skink, the chameleon, the weasel, the hedgehog, cats, some birds and the shore crab (Savona-Ventura, 1979). The Wall Lizard is carnivorous feeding on a varied diet which includes insects, arachnids, molluscs and young lizards. Water is lapped up with the tongue. The animals are oviparous laying cartilaginous shelled eggs towards the middle of April. Hatching takes place around the end of July when large numbers of young start appearing. As with all reptiles, the Wall Lizards are poikilothermic and require an optimum temperature to operate efficiently. This may account for the selective factor which has resulted in the darker pigmentation of lizards living in enviornments where food is scarce as compared to those living in less demanding habitats. The darker pigmentation results in increasing absorption of heat from the surroundings (La Greca and Sacchi, 1957).
Records: Podarcis filfolensisis widely distributed on the Maltese Archipelago and the various islands and rocks each have their own colour forms, some of which have been formerly named as subspecies. Thus the nominal subspecies filfolensis is found on Filfla, while the lizards from Malta, Gozo, Comino and Manoel Island are known as maltensis. The subspecies generalensis is found on General or Fungus Rock and the subspecies kieselbachi is found on St. Paul's Islands. The species is also found on the Pelagic Islands where it occurs as the subspecies laurentiimuelleri. A distinct and as yet unnamed colour form has been described from on Cominotto (Savona-Ventura, 1983).

Family: SCINCIDAE
Chalcides ocellatus Forsk. ssp. tiligugu (Gmelin)
Ocellated Skink
maltese: Xahmet l-art
Size: up to 30 cm long including tail.
Colouration: Dorsally, olive-brown or brown with ocellated spots of white and dark brown, sometimes forming irregular cross bars. Colour may vary from light olive-brown to a darker shade of brown. A superciliary light stripe is present along the whole body length. Ventrally, uniform silvery white.
Biology: Because of the animal's small limbs, progression on a smooth surface appears clumsy. However when in its natural habitat of soil or sand, the skink can move very fast and can tunnel to disappear completely within a few minutes. It is perfectly adapted for this by virtue of its short limbs and its plastic skin. The skink suns itself for prolonged periods in dry places, but quickly goes into some crevice if disturbed. It feeds on a wide variety of insects, small molluscs and spiders and can survive for long periods without water. The main predators are cats, the weasel, the hedgehog, snakes and possibly the kestrel. The skink is oviviparous, producing 4-10 young in the period July to September.
Records: This species has been recorded from Malta, Gozo, Comino, Cominotto and Manoel Island.

References