08/09/2024
For my fellow snake nerds who are into this type of info. 🤓
Here is a bit of a read, for those interested…
What DO YOU KNOW about CARPET PYTHONS and where they came from!?
It’s been a while, and in that time we’ve been given some exciting new information, so let’s do a quick update. Previously, the theory supported here at Pwt Pythons, was that an expansion took place 9000 years ago. At a time when Australia was part of a larger landmass connected to New Guinea. I thought that an early group of Papuan Carpet Python had originated and dispersed from what is now NG, into modern day Australia where they have since adapted overtime. It seems I was wrong, at least partially, but wrong nonetheless. This includes previously posted locality maps, which will be updated accordingly.
I have recently learnt about fossil specimens of Morelia, discovered in northern regions of Australia. With this information in mind, the previous theory seemed unsupported.
So these past few weeks I have been busy reading through multiple papers, gathering information from research in geology, ecology, field work and biogeology; and with these little pieces of information, a larger puzzle has been brought together. With the help of a particular paper published in 2020, detailing extensive molecular studies, tests and their findings, the origins of the Morelia lineage is becoming clear. However, to begin explaining the incredible diversity we see today, I want to take you much further back in time. It is a little bit complicated, so let’s use dot points…
- The Eocene (56-33.9 million years ago). The dawn of a new world, and like many modern animals… Biogeographic reconstruction places the origin of pythons, in Asia at this time.
- 33.9-23 million years ago, the Oligocene epoch, saw a decrease in global temperatures and the spread of grasslands and deserts. Ancestral python groups had seperated and in the process… some dispersed into Africa, while the Indo-Australian lineage had dispersed across the Wallace line and were living in what we now call Indonesia.
- By the early Miocene, (23.3-15 million years ago), some groups had travelled back across the Wallace line, to disperse across SE Asia. While what was now the Australo-Papuan lineage, continued on to disperse into New Guinea.
- Mid Miocene (15-11 million years ago). During this sub-epoch, the Australo-Papuan lineage separated into two groups/clades. Morelia and Bothrochilus; the later primarily remained and diversified in New Guinea, with some dispersing into Australia or back to Indonesia. For the most part, the Morelia group diversified across Australia, with the exception of three seperate ventures back into New Guinea. These three that dispersed back into New Guinea are what we now know as the spotted python, papuan carpet and green tree python.
- By the end of the Pleistocene (1.8 million years ago) each of these diversified clades had settled or ultimately become bound by their respective geographic situations. Allowing ample time between then and now, to adapt to specific ecological niches across the planet.
A handful of papers discuss adaptive radiation, and its association with ecological opportunities. Especially those found on islands, or in some cases, continents that have experienced suitable periods of isolation. As the Australo-Papuan lineage dispersed across the landmass that would someday become Australia and New Guinea, they found an ecologically diverse landscape. At the time, NG was predominantly rainforest, likely giving rise to an early form or ancestor of the Green Tree Python. Although much of northern Australia was also rainforest, (including Uluṟu), there is no evidence to suggest that Green Tree Pythons were widespread across Australia. As the planet warmed up and regions further from the equator began to dry out, what was rainforest, became open woodland and later, scrubland or desert. As the environment shifted, it is likely that a group separated away from the early ancestor of GTP, whilst the later became restricted to the diminishing rainforests.
Having diverged from their rainforest counterparts, a new group of pythons found themselves adapting to a harsher, drier, colder environment. This group would go on to become the Carpet Pythons and Anterasia we know today.
An adaption to the drier climate allowed these pythons to reach new ecological opportunities, which in turn, gave rise to further morphological diversification. Further diversification into these newly available ecological niches resulted in the phenotypic variation that has created the subspecies and perhaps even localities we see in Carpet Pythons today.
A massive thank you to everyone who helped bring this post together. In particular…
Daniel Natusch thank you for answering all of my pestering questions. And for inspiring me to revisit this topic and to further my knowledge and understanding.
Thank you to Damien Esquerre for reading through the draft a number of times, I have been very grateful for your advice and patience.