Environmental Correlates of Facultative Paedomorphosis in Newts from a Greek Biodiversity Hotspot: Is Staying Young Enough to Stay Alive?

Facultative paedomorphosis, the retention of larval traits in sexually mature individuals, plays a crucial role in species ecology and evolution and is influenced by complex interactions between environmental factors. Here, we compile all known cases of paedomorphosis in all newt species in Greece and report 20 new localities, mainly in Northern Pindos National Park. Our results indicate that paedomorphosis tends to occur more frequently in stable aquatic environments in combination with unfavourable external conditions (lack of precipitation and higher temperatures). Furthermore, species-specific patterns related to the occurrence of paedomorphosis were also unveiled: Mesotriton alpestris prefers high-elevation and permanent ponds; Lissotriton graecus occurs predominantly in artificial, lowland ponds; and Triturus macedonicus is associated with a stable hydroperiod and fish absence. Overall, conservation strategies should explicitly account for paedomorphic populations, emphasizing the value of artificial ponds, which are able to support this life-history strategy. Lastly, the Northern Pindos Mountain Range emerges as a major European intra-specific diversity hotspot.