AGE AND SIZE STRUCTURE OF POPULATIONS OF SMALL MARBLED NEWTS (TRITURUS-MARMORATUS PYGMAEUS) FROM DONANA-NATIONAL-PARK (SW SPAIN) - A CASE OF DWARFISM AMONG DWARFS

The body size of specimens of Triturus marmoratus pygmaeus from Donana is the smallest recorded for this subspecies. Snout-vent length avera ges 42.3 mm in males, and 43.9 mm in females. Mean body mass in males is 2.04 g and 2.29 g in females. The age of newts was estimated by mea ns of skeletochronological methods. The maximum longevity recorded was 10 years in females and nine years in males, with one or two years be ing the age at maturity. As in other newts, body size is not a good pr edictor of age, since a wide range of body length was found within eac h age class. Growth in females was substantial in subsequent years, sh owing an overall positive tendency. However, males showed slight or ev en negative growth. Newts from Donana are different from other nearby localities with similar climatic characteristics. This is mainly due t o their short juvenile and terrestrial phase.