Can you help me identify a durio species?

[red durian]

I bought this same durio last season and it does not match the description of any durio I have information for. I only have the fruit to go by and a likely location.  That is to say, I did not see the tree or flower.   I also don't have a camera at the moment.

Fruit size:   12 to 16 cm diameter
Spike shape:  thin isosceles
Spike length:  1 mm
Skin colour:  russet/brown
Fruit shape:  particularly spherical
Seed skin colour:  as durian
Flesh colour:  translucent yellow
Flesh thickness:  very thin
Flesh flavour:  sweet, no bitterness, lower in fat than durian
Flesh aroma:  exceptionally attractive with a caramel hint

Purchased near Papar, Sabah, Borneo, Malaysia for the lowest price of any of the 4 Durio species present (which may indicate that it is local).

[Gouralata]

Hi red Durian
Do you have the local name ?
Is the fruit already opened ?
May be: Durio affinis
              Durio griffithii (Durian kunu or Durian kuning)
             Durian dalit, kura kura ?

Informations from "Fruits, nuts and spices" départment of Agriculture SABAH Malaysia (1993) Found at the Borneo books (KK)

Gouralata (soon in Sarawak)
             

[tabbydan]

You can google pictures of various Durio species and see which best fits.

I was going to guess Durio dulcis but the skin is red and the spikes are much longer than one mm

[Mike T]

At that size it could be durian suluk.

[red durian]

Do you have the local name ?
Is the fruit already opened ?


Gouralata (soon in Sarawak)
           

Durian Ketupat was the name given.  Sorry to forget that.
It was cracked open when I bought it.

Thank you for the suggested species.  I will check into the ones I don't know.  I can say that it is definitely not Durian Kura Kura, though.  I am very familiar with that species. 

[red durian]

All I can find on the www about D. affinis is a drawing of the fruit.  I wouldn't rule it out. 

I doubt it is the natural cross between durian and D. graveolens because the latter has more fat than durian and the one I ate had less fat than a durian.  I suppose it could be a cross from a really low fat durian and a really low fat D. graveolens, but the probability is low.  On the other hand, the D. graveolens genes could explain the thin isosceles spikes, the small fruit size, the thin flesh and the flesh colour.

I should have mentioned this before.  Durian kura kura seeds are dark brown, which rules this species out on another feature.