Mandevilla species ?

Mandevilla species ?;

Creeper for ID : 300411 : AK-2: Again taken at the Flower Show at Jijamata Udyan, Mumbai in Feb,2011.
... could it be Allamanda ?
This could again be Mandevilla sp. or may be a hybrid!!
I thought so too initially but the leaves are different and the flower is very narrow at the base unlike as in Allamanda.