EMBRYONIC-DEVELOPMENT OF THE TERRESTRIAL TURTLE TESTUDO-HERMANNI GMELIN, 1789

Testudo hermanni is a protected terrestrial turtle, the geographical d istribution of which is discontinuous around the Mediterranean sea, an d reduced to three relictual areas in France (Alberes, Maures, Corse). The knowledge of the embryonic stages is necessary for a determinatio n of the sensitive stages to mortality in the stock farmings. The deve lopmental stages described here deal with the most eastern subspecies T. hermanni boettgeri, whose individuals are kept in captivity at the station of observation and protection of the Maures turtle (S.O.P.T.O. M.) at Gonfaron (Var). Indeed, this turtle must not be reintroduced in France, where natural populations of T. hermanni hermanni are living. The embryos of T. hermanni boettgeri came from thirty three clutches. The eggs were incubated at 28-degrees-C in the SOPTOM laboratory. Twe nty six stages are described between egg-laying and hatching. These st ages are comparable to those described for the freshwater turtle, Chel ydra serpentina (Yntema, 1968). Some minor peculiarties, detected at t he last stages, concern the scale system for the tail and the limbs. T he development of the terminal claw of the tail, which constitutes a m orphological characteristic for the species, is described for the firs t time. The small axis of the egg generally coincids with the antero-p osterior axis of the embryo. This tends to limit the length extension of the embryo, whereas the great axis of the egg allows a width extens ion of the embryo. Just before hatching, the carapace width is greater than its length. In spite of these peculiarities, the complete study of the embryonic development, carried out for the first time in a terr estrial form, confirms the great homogeneity of Chelonians. This homog eneity was already suggested by the comparison between the development al stages of leatherback sea turtles and other aquatic turtles (Renous et al., 1989).