In general terms, a “living fossil” is a species of animal or plant that has survived for a long period of time without going through any significant evolutionary changes. However, this doesn’t mean that they’ve stagnated or not changed at all – they will have often evolved at a molecular level.
So, why am I bringing this up?
Well, Australia is perhaps uniquely positioned as the home of a number of interesting living fossils, yet it is probably our least visually interesting one that is the most significant. But I’m getting ahead of myself, let’s start with a quick rundown of some of our most interesting living fossils.
The Elephant Shark is confusingly not a shark at all, but rather a type of fish known as a chimaera which is distantly related to both rays and sharks. Elephant Sharks look the part too, and you’d be hard-pressed to find another animal that shares the same unusual appearance. Elephants Sharks haven’t changed significantly in over 230 million years!
Pig-nosed Turtles can be found in the Northern Territory and some parts of New Guinea, and they show evidence of bridging the gap between seafaring and freshwater-based turtles. Aside from having the distinctive snout which gives it its name, the Pig-nosed Turtle also has small flippers, making it unusual for a river-dwelling turtle.
Australia is also home to the Queensland Lungfish, a family of fish that dates back 380 million years. That means that these fish were around at the same time as the dinosaurs, and since the Queensland Lungfish hasn’t changed much in 100 million years, they didn’t look much different back then either.
So that brings us back to our original living fossil, that doesn’t look like much, but is incredibly interesting.
Stromatolites are layered mats of cyanobacteria that look like big dirty stones, but this dull appearance hides their venerable age and significance. Stromatolites are one of the oldest know lifeforms on the planet and date back to the beginning of life itself. They played a critical role in the development of our oxygen-rich environment, and they are so old that we might be able to trace our genetics back to them.
If you thought your immediate family was bad looking, fancy introducing this lot at your next family reunion.