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TaxonomyBrowseInfoImagesLinksBooksData
Photo#42232
Bug - Rasahus hamatus

Bug - Rasahus hamatus
Okeechobee County, Florida, USA
February 4, 2006
The bite feels like a bee sting.

Moved
Moved from Rasahus biguttatus.

I agree
The crux with that key is that it is, according to title, "literature based".
Keys should be based on knowledge and observations made on specimens. Incongruencies like those observed will not as easily been included then.

The colour of this Rasahus is, you are right, just as described for hamatus, and similar as in specimens of hamatus in the guide. The statement for biguttatus "...clavus largely yellow" on the other hand, indirectly tells us that base of is will be black - so, no substantial difference.
The same colouration is observed in this Alabama specimen (probably out-of-range for hamatus):

The PDF key you referred to says, in part:
"Inner portion of basal half of corium as far as tip of clavus is yellow; clavus black at base;...... R. hamatus."

This is an accurate description of what is shown in the bug above, which you've identified as biguttatus. If those characteristics are not unique to hamatus, they can't be used to identify the species, so the entire statement should be removed from the key.

The couplet "body narrow" / "body broad" I interpreted to refer to the connexivium being exposed or not. I did not trust in the figures.

Moved
Moved from Rasahus. Look for reasons under:

 
Why not R. hamatus?
There's not much yellow in the upper part of the hemelytron (similar to this photo) - certainly not nearly the amount as seen in the biguttatus specimen here.

 
Because . . .
morphological features may more be trusted than colour. This key does not tell a REAL difference in colour (a tendency, rather). The abdominal character to me seems more decisive, and is supported by images in the guide.
What the key does not tell: insofar visible, the connexivium in R.hamatus is pale throughout, not banded in black-and-white as here.

 
key not reliable; needs fixing
The PDF key you referred to says, in part:
"Inner portion of basal half of corium as far as tip of clavus is yellow; clavus black at base;...... R. hamatus."

This is an accurate description of what is shown in the bug above, which you've identified as biguttatus. If those characteristics are not unique to hamatus, they can't be used to identify the species, so the entire statement should be removed from the key.

The same key couplet also says "body narrow" for hamatus, and "body broad" for biguttatus. I see no noticeable difference in body width between this photo of hamatus, and the above photo - or any of the others pictured here. The body width characteristic is unquantified, therefore unreliable, and should also be removed from the key.

That leaves only the connexivum characteristic. In this case, I think a more accurate and useful key would read something like:

2. connexivum widely exposed, banded black and white...... R. biguttatus
2a. connexivum not widely exposed, pale throughout...... R. hamatus

...assuming that connexivum color is a consistent/reliable characteristic.

The diagram of hamatus in the PDF doc is misleading. I suspect that, during resizing of the image, its width was reduced by about half, while its height remained unchanged. Live individuals are not laterally compressed like that.

Rasahus
Looks like Rasahus, for example:



Patrick Coin
Durham, North Carolina

 
I agree.
I agree with Pat. Nice image, Jeff!

 
Thanks
for your help, guys.

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