Sphinx Larva ID

[gwang]

Hi fellow lepidopterophiles,

Well, I found a large sphinx (8cm) larvae taking a 'walkie' today and
can't seem to ID it.  It's like any other sphinx larva, with the usual
horn and lines and such, but there are also two pairs of tubercles about
4mm high on the first two thoracic segments.  Moreover, the line on the
back of the larva isn't just a line, but is actually comprised of raised
bumps (8 per segment).  It's almost like the back of a tiny iguana.  The
lateral lines are also similar, but the bumps are less pronounced.

And also, it seems to have sustained some damage to it's head casing. 
It's still alive and seems normal, but I'm not sure if it will be albe
to pupate.

Any help would be greatly appreciated.

TIA,
Xi Wang