| T O P I C R E V I E W |
| loongfah |
Posted - 22/05/2024 : 09:37:45
Dear all
How to differentiate Ostedes brunneovariegata from O.discovitticollis? Below is an image of O.discovitticollis that I took from Basel museum. It is not a type specimen but is "Breuning determined", and is placed side by side with the O.brunneovariegata type in Basel (the same one that Dan Heffern took here http://bezbycids.com/byciddb/wdetails.asp?id=18694&w=o), so I presume the determination per se should be reliable. I didn't do a side by side comparison between these two then, but now I find it quite difficult to separate them.
O.discovitticollis specimen in Basel:
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In Breuning revision for old world Acanthocinini, the key for Ostedes separates these 2 species in the 1st couplet:
Elytres tronques obliquement ou echancres à l'apex, l'angle apical marginal plus ou moins pointu . . . . . 2. (goto most of the Ostedes species, including discovitticollis)
Elytres faiblement tronques à l'apex, l'angle marginal obtus . . . . . . . . . . . . . . . .. . . . . . . . 24. (goto brunneovariegata)
I find this character quite difficult to judge, depending on viewpoint etc, and I have specimens from Singapore (one example below) that have outer marginal angles that range from obviously obtuse to increasing pointed (BTW, does "pointu" simply mean pointed/sharp without the meaning acute?)
Singapore specimen:
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| 2 L A T E S T R E P L I E S (Newest First) |
| loongfah |
Posted - 22/05/2024 : 14:57:38
Thank you Xavier!
The marginal angle is larger than 90, and the lower eye lobe is about 2 times as long as cheek. So it would be a O.brunneovariegata (lower eye lobe 2.5 times as long as cheek in discovitticollis). |
| Xavier |
Posted - 22/05/2024 : 13:58:13
l'angle apical marginal plus ou moins pointu < 90°
l'angle marginal obtus > 90°
It's difficult to appreciate, but we'll have to make do without proper photographs of the holotypes.
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I can't see from your photograph whether the marginal angle is more or less than 90°.
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