My 16.5 month DS usually sleeps around 1.15 for 1.5 - 2 hours and about 30 mins in morning too.
We thought we'd try drop morning nap as none of his mates still nap then. A few times he's been fine, other times get sleepy so we've given him a nap and he's gone into deep sleep.
Is it unusual for his age to still need it?