Possible Clues:

• Large extinct mammal
• Chap without singular fuss getting antiquated browser
• Extinct megafauna species whose name derives from the Greek for 'breast tooth'
• Old lady heartlessly trampled ancient creature
• Man stood trembling, seeing such a creature
• Initially shocking commotion, with chap circling extinct mammal
• Huge beast stood out in island
• Ancient animal terribly mad — not so!
• Samuel goes back to Mafia boss in what looks like old jumbo
• Mum's old teacher preserves head of this extinct beast