Which lionfish from Krabi, Thailand?

I saw several of these pretty ones around Krabi, Thailand. I am confused of the species, though. It doesn't have the spots of Pterois antennata; the tips of pectoral fins seem way too long for it to be Dendrochirus zebra; Pterois mombasea is the closest match I have found, but I am not too sure about that either (does it even live that far north?). Any help?

Common name: Threadfin I think

scientific name: Dontus knowus

Couldn't find threadfin lionfish/turkeyfish from Fishbase, and my books didn't help either. Further hints are very welcome!

P. antennata (sp??) perhaps?

What was the size? If a juvenile, the pectorals often have these rays. In Leiske and Myers, it looks most like your guess Pterois mombasae with less prominent spots than in the illustration. Range says north to Sri Lanka, and east to PNG, so although at the northern extreme, seems possible.

Marli

I initially also thought this might be Pterois antennata (Spotfin Lionfish), as James suggested. But now I don't. Here (below) is what I think is a P. antennata. The head is quite different, and the spots on the fins are much more prominent.

The juvenile P. Volitans (Common Lionfish) also has prominent pectoral fin rays, but they look quite different too:

I've never been satisfied with the listings on the entire scorpionfish family in any of my sourcebooks. There seem to be quite a few scorps in the Indo-Pacific that don't show up in any of the standard works, (that I have), but are clearly distinct species.

Frogfish

All the ones I saw (maybe 3 or 4) were between 10-15 cm long. I am sure they were not juvenile Pterois volitans, as I photographed several of those on the same trip. Does anyone have images of Pterois mombasea (not dead ones like in Fishbase...), or of juvenile/adolecent Pterois antennata?

Or, has anyone seen these guys somewhere else? Even knowing something about distribution/commonness(sp?) would be useful hint.