Sorry, I don't know either, so I'm no help!
However your post has made me recall that 12 months or so ago DS1 was singing this little song over and over again and the only words I could make out clearly were "bum" and "mummy". I had absolutely no idea what bum/mum song he could be singing (!) until I asked daycare and it turned out to be a very cute bumblebee song.
DS1 is a good one for making up words to baa baa black sheep and twinkle twinkle etc ... the dinosaur ditty wouldn't be something made up like that, would it?