Kelly provided good key identifiers to help narrow down the type. My experience with the few hybrids that I have seen, all lacked subocular scales typical of P. brongersmai. Once additional point of confusion comes from the exporters when they list the snakes as "sumatran blood or short-tail python". There is some natural integration that appears to occur and what you get might be a sumatran integrade between P. curtus and P. brongersmai. There is a great paper with graphical resprsentations of the head scalation and other identifiers out on the web. If you want to explore this technical paper, here is the citation/reference:
Heavily exploited but poorly known: systematics and biogeography ..

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