I have been trying to figure out the key ID features for the pavana group Nacadubas, but with not many images available online of live specimens, some of them have been rather challenging, especially N.pendleburyi and N.solta. Would it be possible for you to do an overview of the key IDs? Thank you.
These are some features I have noted/read, splitting the group into 2, with and without metallic scales in the tornal spot.
With metallic scales:
1. N. pactolus
- FW post-discal band typically straight
- Submarginal spots quite rectangular
- HW submarginal spot 6 large, spots 4 & 5 flattened.
2. N. hermus
- FW post-discal band typically straight
- FW submarginal spots chevron shaped
- HW post-discal band in spaces 4 & 5 very close to HW submarginal band
3. N. pavana
- FW post-discal band typically straight, sometimes with dislocations
- Prominent white 'bar/band' running through submarginal spots
- Marginal spots bar-like
4. N. russelli
- Marginal spots oval/lozenge-shaped
- Outer margins of submarginal spots pointed
5. N. angusta (should be distinct enough)
- Broad and diffused whitish striae
- Strongly contrasting black submarginal and marginal spots
- HW submarginal spot 6 large and rounded
Without metallic scales:
1. N. sanaya
- FW post-discal band typically dislocated at vein 6
- HW post-discal band well separated from HW submarginal band
2. N. subperusia
- FW post-discal band gently curved but not markedly dislocated towards costa
- HW post-discal band in spaces 4 & 5 very close to submarginal band (almost touching)
- HW submarginal spots strongly concave and dark, contrasting greatly from ground colour
3. N. pendleburyi
- FW post-discal band gently curves towards costa
- HW post-discal band well separated from HW submarginal band
Post 29.
The 4-line Blues are very difficult to Id from the underside alone in many species and it is likely there were many mis-identifications in the past.
The dark striae within the bands are important in the Ids.
A. Dark striae within bands strongly developed ,appearing black.
Metallic scales on HW tornal spots always strong.
B2. Nacaduba pactolus.
White striae buff, enhanced.
Metallic scales on tornal spot strong.
HW submarginal spot 6 quadrate & connect sharply to a narrow band formed by submarginal spots 4 & 5; Distinctive.
Male. http://www.butterflycircle.com/check...-%20horace.jpg
B6.Nacaduba pendleburyi
FW postdiscal band not dislocated.
HW with the submarginals & postdiscals in space 4 & 5 well separated.
Upperside with the FW black border a thread & expanded at the apex in the male (Diagnostic.) Added: FW marginal & submarginal spots narrow, submarginal spots 4 & 5 pointed.
B7. Nacaduba solta. FW with a very straight postdiscal band as in N. calauria
This species is not found in Singapore.
TL Seow: Cheers..
PS. It is very likely that what was thought to be one variable N. sanaya species in Singapore actually comprise two equally common species, ie. N. sanaya & subperusia..
Previous use (for comparison) of N. perusia images with only features of dark markings & unbroken postdiscal band ( from neighbourig countries ) is probably untenable.
PS 2. The two males from Thailand match the image of N. pendleburyi male in C&P4.
HW with wide spacing of postdiscals & submarginals in space 3, 4, & 5.
FW marginal & submarginal bands narrow, submarginal spots 4 & 5 pointed. https://pamsbutterflies.com/butterfl...-sanaya-elioti
I was looking through some iNaturalist observations and this one seems a little different to me with the way the FW post-discal band curves: https://www.inaturalist.org/observations/71003020
Could it be N.pendleburyi? Of course without dorsals it is difficult to confirm.
There is very little correct image of N. pendleburyi
All known shows the marginal & submarginal spots/bands to be very narrow.
While the band may be curved in pendleburyi,similar bands are also seen in sanaya & subperusia, & probably several others.
I would leave it as N. sanaya since the submarginals are large.
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