Separation of C. santana and C. acuta

Looking at my Curetis images and trying to sort them out. Three images of a Curetis species from Mae Ping, northern Thailand. All three images the same individual. According to the literature there are 4 possible Curetis species occurring in northern Thailand - Santana, acuta, bulbis and saronis.
From the size/shape of the upper forewing red patch, this should be either santana or acuta. I would have said, based on the deeper notch on the upper edge of the red patch that this should be acuta. Also the shape of the trailing edge of the hindwing (with a small bulge on the end) would be more like C. acuta. I would welcome comments.

Many thanks

Attachment 24666

Attachment 24667

Attachment 24668

The deep black notch (tooth or dentate mark), ID'ed it at once as C. acuta dentata.
The HW lobed tornus (the 'bulge') is a helpful feature.

C. saronis have the FW band parallel & is without the speckled black dots.
http://1.bp.blogspot.com/-YjzoWBJ7Y2...nbeamM-KSK.jpg

The other three have an oblique FW band & black dots allover.
They are easily confused on the underside.

C. acuta dentata. Often sharp pointed FW & lobed HW; dsf very angular.
The upperside black tooth is diagnostic ,but may not be well-formed . Forms in S. China do not have the tooth mark.
Underside HW band in space 6 & 7 straight & lined up with the cellend mark which is usually prominent. (Alignment less in dsf.) May form a long line running down to tornus..
https://species.wikimedia.org/wiki/C...aMMUpUnAC1.jpg
http://www.ifoundbutterflies.org/med...613a00d2-1.jpg
http://www.ifoundbutterflies.org/med...63846be3-1.jpg
http://www.learnaboutbutterflies.com...%20dentata.htm
https://farm9.staticflickr.com/8509/...1e39cc7a_b.jpg

C. bulis bulis.
Most often confused with C. acuta .Many angualr forms (dsf) of C. acuta have been placed as C. bulis.
HW postdiscal mark 6 large & convex, that in space 5 small & tuck underneath it. The band is not aligned with the cellend mark which is weak.
Submarginal spots 6 & 7 aligned & joined end to end.
http://www.jpmoth.org/~dmoth/Butterf..._070702139.jpg
http://www.jpmoth.org/~dmoth/Butterf...070501031B.jpg
http://www.ifoundbutterflies.org/med...0a3b7999-1.jpg
http://www.ifoundbutterflies.org/med...0a3b7999-2.jpg
http://www.ifoundbutterflies.org/med...94a2acd488.jpg
http://www.ifoundbutterflies.org/med...94a2211663.jpg

Very angular form but on the HW the posdiscal band & the cellend mark are widely out of alignment.
http://www.ifoundbutterflies.org/med...0e520628-1.jpg

C. santana.
HW postdiscal spot 6 & 7 aligned & straight, & not aligned with the weak cellend mark .
HW submarginal spots 6 & 7 not aligned & often separated.
Upperside may present with a weak 'tooth'.
http://4.bp.blogspot.com/-jhhzwzMVeD...unbeam-KSK.jpg
http://3.bp.blogspot.com/-t9119-E8An...S_adult_05.jpg
http://2.bp.blogspot.com/-bnDbh-3WAV...adult_01_c.jpg
http://www.butterflycircle.com/check...am)--Sunny.jpg

TL Seow: Cheers.

Many thanks for the confirmation and detailed reply. Will be having a closer look at my other photos.

The three species can be so confusingly similar that I thought to pick out pix with clearly visible features for future reference.

All three: Underside black-speckled & FW band oblique.

Curetis acuta dentata. Often with sharp FWs & lobed HW ;HW postdiscal band in space 6 & 7 more or less aligned with cellend mark , often extending downwards.
All Thai examples.
http://4.bp.blogspot.com/-nzV2npDLXN...march+2013.JPG
http://www.dnp.go.th/FOREMIC/NForemi...%B8%81%201.JPG
https://c1.staticflickr.com/2/1446/2...57f0f8b0_b.jpg

Curetis bulis bulis.HW postdiscal spot 7 usually large & convex with spot 6 small & tucked underneath ,band out of alignment with cellend; submarginal spot 6 & 7 in line often joined.
Thai examples.
https://wingscales.com/content/record/172-1-cde3f.jpg
http://m6.i.pbase.com/g9/25/686825/2...6.KebMw2Ne.jpg
http://m9.i.pbase.com/o6/25/686825/1...yanSunbeam.jpg

Curetis santana malayica. : HW postdiscal spot 6 & 7 in line(ie. spot 6 not tucked under spot 7),not aligned with cellend; submarginal spots 6 & 7 dislocated ,not in line.
All Singapore examples.
http://woxiong.butterfly-photo.com/a...0604_sg_46.jpg
http://1.bp.blogspot.com/-0ICztPUghR..._female_01.jpg

TL Seow : Cheers.
PS upperside also confusing.
C. bulis with 'tooth mark' : C. bulis have HW basally broadly black.
https://commons.wikimedia.org/wiki/F...LBDSC_0209.jpg
https://farm2.staticflickr.com/1458/...80101d19_b.jpg
C. acuta dentata.
https://farm8.staticflickr.com/7498/...2ff63bdb_b.jpg