Friday, October 4, 2013

Three new species pages, and notes on Erionota torus from Kerala

Krushnamegh Kunte reported on ButterflyIndia yahoo group:

We have three new and exciting species pages on the website:

Erionota torus – Rounded Palm-redeye:

Lethe ramadeva – Single Silverstripe:

Allotinus unicolor – Plain Mottle:

Of these, E. torus is of special interest. This species was not known from peninsular India until now. The credit for this discovery goes to David Raju, who in August found its caterpillars devastating banana plantations around Thattekad in Kerala. Since then, several people have found the caterpillars in other parts of Kerala, so this is currently quite widespread in the coastal strip. Vivek is in the field surveying the current range of the species and damage done to the banana plantations, so we will know more about this soon. The case of Erinota torus is taxonomically interesting as well. People on Facebook have been using various names for it: Erionota acroleuca, Erionota acroleuca apex, Erionota hiraca, Erionota hiraca apex, Erionota hiraca apicalis, etc. I knew about the Kerala records from David’s first sightings and many people had asked me about this species in the past 40 days, but I wanted to confirm the species identity before I created the species page. I knew since last year after seeing specimens in the BMNH that Evans’s (1932, 1949) morphological key to Indian Erionota was not useful in separating the species. It is unfortunate that many people still blindly use these morphological keys without double-checking with other resources and without realizing that the only way to distinguish these species is by dissecting the male genitalia. To confirm the species identity, Kalesh and I recently dissected four males that we raised from caterpillars. Their genitalia match those of torus and no other species. Two of the dissections are available on the species page for your reference. From the variation that I have seen in torus in recent weeks and among all the species in the BMNH last year, it is clear that the external differences mentioned by Evans to separate torus, thrax, and hiraca (=acroleuca) are not reliable in distinguishing these species. The characteristics mentioned by Evans included the color of the UPFW apex, convexity of the FW termen and perhaps the color of the antennal club. That is, there is too much variation in these characters within species so that one cannot reliably distinguish between them from external characters alone. We will post images of male genitalia of other Indian Erionota on the website in due course.

Lethe ramadeva is very exciting due to the rarity of this species. I wonder whether this is the first ever photographic record of the species.

Congratulations to David and Anurag for these important and exciting discoveries!

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