Forum Entomologi Italiani

TBL 2 mm, P. Krasensky legit. La morfologia delle antenne potrebbe implicare una convergenza adattativa con Streblocera (Braconidae Euphorinae).

tribe: Batrisini Reitter, 1882
subtribe: Batrisina Reitter, 1882
genus: Cratna Raffray, 1890

Cratna torticornis Raffray, 1890................Malaysia and Singapore

Attualmente, 28 specie del genere Cratna, dalla Malesia, Taiwan nord-est dell'India, Nepal, Sri Lanka, Sumatra meridionale e Borneo

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Research Fields
Taxonomy, ecology, biomonitoring , faunistic of Staphylinidae

Thank you, Jan! Are there reliable id keys and/or recent systematic revisions regarding this genus? Illustrations in the 1890 original description are quite misleading. Also, C. torticornis appears not to be the only species with such morphology... Help!

to your picture, in the text this ...........page 64...........Cratna torticornis Raffray (Fig. 11)


Lobl I.:Revision der Gattung Cratna Raffray (Coleoptera, Pselaphidae).
https://www.biodiversitylibrary.org/pag ... 1/mode/1up

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Research Fields
Taxonomy, ecology, biomonitoring , faunistic of Staphylinidae

Nomura & Idris 2003 mention only 7 spp in total, in Löbl 1975 the total is 12 spp, wikispecies reports a total of 13 spp. Are there other publications or descriptions in order to get to 28 spp?

The sp in Figure 11 is treated as C. torticornis at p. 64 while at p. 72 is treated as C. abdominalis, the latter sp not being mentioned elsewhere in this publication... Is it just a lapsus or what?

The sp, or perhaps the spp?, described in the drawings do not seem to correspond to any of the photographic images. In this case the crucial details are the fifth and sixth antennomers: in the drawings they form a more or less right angle, while in the images we can clearly see how they form a semicircle.

Educated guess: Cratna abdominalis Löbl 1975 ?

I do not have any information now.
I'm at the airport, today to fly to Egypt.

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Research Fields
Taxonomy, ecology, biomonitoring , faunistic of Staphylinidae

3 hypotheses: 1, drawing error; 2, actually different spp; 3, perspective illusion

By carefully comparing the images I have come to the conclusion that the most plausible hypothesis is the third one. It must be said that such species are quite small and not very easy to prepare. Both fifth and sixth antennomeres appear to have a curved shape even in the 1975 drawing; by rotating them through their mid-joint they might seem to form a semicircle from a certain POV while from another POV they might appear more right-angled. The first hypothesis has to be discarded as it is not plausible that such a skilled artist would be lost in such a macroscopic blunder; in other words, most certainly it was drawn like that because it was like that. To verify the second hypothesis we should first have to discard with absolute certainty the third one.