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Harpegnathos |
Name that Ant #86 (3 Feb 2008) |
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This one is from Mali. Please I.D. to species.
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Dr Ant |
#1 | |||
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Looks like Aphaenogaster
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MrILoveTheAnts |
#2 | |||
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Would that be a spine on the waist segment?
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Harpegnathos |
#3 | |||
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If you are refering to the apparent small protrusion on top of the petiole, forward of the node, it might be a spine or it might be something behind the
petiole. I can't tell. I don't have the specimen anymore, so I can't check. Better not rely on it for identification.
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nugi81 |
#4 | |||
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I'd go with Pheidole rugaticeps Emery 1877. Although some parts are different.
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Harpegnathos |
#5 | |||
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Any more guesses?
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Dr Ant |
#6 | |||
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And so it is, H!
I was being coy and purposefully misleading (hence the wink emoticon) with my Aphaenogaster suggestion. Looks like the minor of Pheidole megacephala to me. |
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Harpegnathos |
#7 | |||
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Dr. Ant, you know I am humorless and incapable of grasping irony or subtle wit, but I was able to detect that your "Aphaenogaster" comment
wasn't a serious effort at naming this ant. However, this ant does resemble Aphaenogaster at first glance, so that when I first saw it in Mali I
had brief hope that I had discovered an African Aphaenogaster. Such a discovery would have eased the confusion I feel about the absence of
Aphaenogaster in sub-Saharan Africa. The genus is everywhere else, so why not Africa?
This NTA isn't drawing much interest or many guesses, so in case there is someone else out there who wants to give it a shot I wanted to direct them away from your red herring and toward Dr. Taylor's most excellent web site. H |
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Dr Ant |
#8 | |||
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In a sense, there are Aphaenogaster in Africa, in the form of the closely related and in some cases nearly indistinguishable (at the genus level)
Messor sp. But it does seem something of a mystery why the more typical, gracile, mesic forest grade of Aphaenogaster is missing.
The situation is paralleled, however, in other taxa of ants, and beyond. It may have to do with the prevalence of a continent-wide, relatively dry climate history. And perhaps as or more important, this is combined with 100,000s of years of human presence and the accompanying habitat management fires that, according to anthropologist Omer Stewart (Forgotten Fires, Oklahoma U. Press, 2007) virtually all hunting/gathering and primitive agriculturalist peoples have used to modify vegetation to their own ends -- resulting in grassland or savanna dominance in all but the most humid, tropical regions. |
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Harpegnathos |
#9 | |||
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Last call for guesses....
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Harpegnathos |
#10 | |||
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Nugi81 got it right, as usual: Pheidole rugaticeps. Dr. Taylor identified this ant from a sample that included one major and several minor workers.
In Ants of Africa, Dr. Taylor notes that Pheidole is a "very large and taxonomically confused genus, with a multiplicity of nesting sites and foraging habits. Bernard (1952) noted there were 76 species known from Africa, of which 44 were from "French West Africa"; and described the classification as a maze, complicated by the presence of workers and true soldiers, with enormous heads. Because of the relative similarity of males, queens and workers, he found the soldiers with distinct variations to be the only useful form for distinguishing species. Personally, I too found the soldiers, in general, to be much more useful in distinguishing the various species." Nevertheless, he provides a "provisional key to minors of species and separable forms." The first couplet in the key asks whether the postpetiole is wider than long, a judgment more easily made from a top view than from the photo provided. A top view would have shown that the postpetiole is longer than wide, indicating rugaticeps group; total length of just over 3mm, plus colors and spine lengths help to distinguish this specimen from three other specis in the group. If one takes a wrong guess at the first couplet, the key winds through a number of factors, many of which are also not readily determined from the provided photo. One might end up anywhere, including at P. megacephala, which should be slightly smaller than this specimen and has more of a domed rather than impressed mesonotum. I note that the P. megacephala minors pictured on Antweb have tremendous variability. As Dr. Ant himself has said in the past, identifying Pheidole to species is difficult. H |
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Dr Ant |
#11 | |||
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P. megacephala minors are closer to 2.5mm in length, so the larger size alone could have guided me to another species, had I noticed it.
Good one, Harpegnathos! And bravo, Nugi! |
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