Adaptation and evolution in Gallotia lizards from the Canary Islands: age, growth, maturity and longevity Jacques Castanet1, Marcos Baez2 1 Equipe de Recherche "Formations Squelettiques" & UA CNRS D 11 37, Université Paris 7, 2, pl. Jussieu, 75005 Paris, France 2 Departamento de Zoologia, Universidad de la Laguna, 38206 La Laguna, Tenerife, IslasCanarias, Spain Abstract. Qualitative and quantitativecomparisons of histological data recorded from growing bone from sevenextant and extincttaxa of Gallotia showthat theselizardsdo not have the same longevity, reach sexual maturity at various ages and probably have different growth rates which are in reverse proportion to the specific size of individuals in each taxon. In term of relative growth, the highest rate is seen in the smallest taxon (G. atlantica) and the lowestin the largest taxon (G. goliath). It appears that differences betweenthe maximum size reached, irrespective of the size of hatchlings, are only the consequence of changes in longevityallowing a more or less protracted growth; they are not due to differences in growth rates. On the basis of these data we discusssome points relating to adaptive strategies and evolutionary featuresof these lizards. Introduction From many points of view, the situation of the Lacertidae living in the Canary Islands is very unusual-if not unique-and makes this group a very interesting model for the study of several interrelated biological problems. The lizards all belong to the same genus Gallotia, and are endemic to an archipelago of seven main islands and many islets (fig. 1). All the living taxa are allopatric, with one exception on Hierro and what may be a very recent introduction on Gran Canaria. The high chromosome number (2n = 40) of Gallotia (Cano et al., 1984) against 36 < 2n < 38 for the other Lacertidae, probably indicates the antiquity of this genus and its affinities with ancestral forms (King, 1981; Baez, 1987a). The genus is polyspecific with four currently extant species (some with fossil material) divided into many subspecies and at least one extinct species, G. goliath, the largest lacertid known so far. The diversity of intra- as well as inter-specific body sizes is a major aspect of variation in these lizards. Although some relationships between specific size and island size (Boettger and Muller, 1914; Baez, 1982) and between body sizes and variation