BACK FROM EXTINCTION

Some species are thought extinct for decades, before magically reappearing. Introducing some of the Lazarus taxon.

Since the dawn of time plants and animals have had to face immeasurable obstacles to ensure the perpetuation of their species. Catastrophes from the ice age to human intervention have wiped out countless species throughout history. However, some animals, after being thought extinct for decades, even centuries can reappear as if rising from the grave. These species belong to the ‘lazarus taxon’ and their natural histories are often tied with tales of mystery, resilience and discovery.

Adelaide Pygmy Blue Tongue

Tiliqua adelaidensis

Thought extinct for 30 years.

The Adelaide pygmy blue tongue skink is a species of lizard that was considered extinct for 30 years. The smallest of the blue tongues, T. adelaidensis reaches just 10cm in length. In 1992, a herpetologist in South Australia discovered a brown snake (Psuedonaja textilis) which had been killed on the side of the road. Being an inquisitive herpetologist, he decided to dissect it. A long-lost pygmy blue tongue was found in the digestive tract of the snake and inspired fresh herpetological efforts to find the missing species.

It is thought the Adelaide pygmy blue tongue was missing for such a long time because of its cryptic burrowing behaviour. T. adelaidensis inhabits very specific, unused spider burrows in the South Australian grasslands. Rarely venturing from their burrow, the pygmy blue tongue is much more secretive than the common Tiliqua species regularly seen in Australian gardens. Adult lizards will often raise their young for almost a month in the same burrow before they outgrow their crowded home and search for a burrow of their own. This underground lifestyle, although very secretive, provides protection from predatory birds and bush fires which the lizards would be exposed to abovesurface on their open grassland habitat.

Being so secretive with a very restricted range of just a few locations just north of Adelaide, captive breeding efforts for this species were largely unsuccessful for many years. As the window to save the species began to close, Monarto Zoo in South Australia finally managed to breed the pygmy blue tongue. AlyssaJane Tucker, Spokesperson for Monarto Zoo said: “Last year, we were thrilled to announce a world-first in conservation with the successful captive breeding of 14 endangered Pygmy Blue-tongue Lizards. This year, we are proud to continue this success with 12 neonate Pygmy Blue-tongues joining the Monarto Zoo family! Our breeding success represents a major contribution towards the conservation of one of our country’s rarest native reptiles and this year’s births are a significant step forward in safeguarding the species from extinction.”

Of course, much research has been done around the viability of reintroduction and how well captive populations will be sustained in the future. Professor Mike Bull of Flinders University in South Australia has led much of the research that has slowly uncovered the natural history of these secretive skinks. He has discovered that livestock grazing intensity, ‘risky’ behaviours in neonates and co-existence with insects in the burrows could all affect the success of wild relocations. With a dedicated team of researchers making regular breakthroughs, Tiliqua adelaidensis is receiving an incredible level of conservation support. One man’s decision to dissect an eastern brown snake could have been the catalyst that saves this species from extinction.