15 replies to this topic

[dspdrew]

1. Location of collection: Near Joshua Tree National Park, California.
2. Date of collection: 8-3-2014.
3. Habitat of collection: High desert.
4. Length (from head to gaster): 7 mm (major);  12 mm (queen).
5. Color, hue, pattern and texture: Red head and anterior thorax, dark grey/black gaster and posterior thorax (major); Red head, dark grey/black gaster and thorax (queen).
6. Distinguishing characteristics: 
7. Anything else distinctive: 
8. Nest description:

 

Queen 1

 

 

 

 

 

 

 

Queen 2

 

 

 

 

 

Major

 

 

 

[dspdrew]

I am pretty sure this is either M. semirufus or M. placodops.

 

Only problem is the head is weakly orbiculate and M. placodops should be strongly orbiculate, not to mention I don't think they're really supposed to be found this far west.

 

But...

 

To be M. semirufus, the queen's longest occipital and mesoscutal hairs should be one half to one times the length of the eye, and the longest scutellar hairs no less than .9 times the eye length, yet none of those hairs are over .5 times the length of the eye. Also the queen's head width should be less than 2.3 mm, while her head width is at least 2.3.

 

By looking at my pictures, if anyone thinks I'm wrong about the hairs, let me know.

[Gregory2455]

How dare you pin a queen!!! Just kidding, but where did you get the dead queen sample from?

[dspdrew]

It was one of the alates we found the day they flew. I might have saved some of the queens that have died too.

[Gregory2455]

So, she died naturally? Or did she fall into the bottle of alcohol like the that Cardiocondyla queen?

[dspdrew]

She still had her wings, so she fell in unfortunately.

 

Edit: Now that I think about it, we found so many of these that I probably didn't bother to take a specimen, so she likely died later naturally.

[Gregory2455]

You could have given her to me! Hahaha, I wonder why I found none... 

[gcsnelling]

Why are you rulinbg out M. mendax??

[dspdrew]

Edit: I think this actually could be M. mendax after all. I read part of the key wrong. Also MOD appears to have two definitions.

 

Well, for the M. mendax worker, the key says "Longest hairs on pronotal dorsum and disc of second tergum at least 0.6 x MOD, usually about 0.75 x MOD; head of major with margins, in frontal view, nearly parallel".

 

Took me a while to figure this out a while back, but so everybody knows, MOD is Maximum Ocular Diameter, pretty much the same as EL - Eye Length. Correct me if I'm wrong.

 

Not sure about my specimen's head shape, but the shortness of its hairs again--this time the worker and not just the queen.

 

As for the queen, to get to M. mendax the key says "Parapsis with punctures usually of two sizes and variably spaced, never uniformly dense; malar area usually with few or no standing hairs; HW usually less than 1.9 mm". "Parapsis closely, uniformly punctate; malar area with abundant standing hairs; HW usually in excess of 2.0 mm"

 

Not sure about the standing hairs on the malar area, without experience I don't exactly know for sure which of those would be considered standing, but it looked like quite a few to me.

 

 

Then there is the head width, and the head width of this major is over 2 mm.

 

 

Edit: Fixed a mistake I made.

[AntsAreUs]

Drew I would say this is Myrmecocystus koso.

Edited by Gaige Daughtrey, November 30 2014 - 10:20 AM.

[kellakk]

Snelling 1976 defines MOD as "Minimum Ocular Diameter: The minimum diameter of the eye as measured with the head in full lateral aspect."  I think that means the horizontal distance across the eye, which is usually the shortest (as compared to the vertical distance, which would be the longest).  That may help you with your ID's if I'm right.

[dspdrew]

Snelling 1976 defines MOD as "Minimum Ocular Diameter: The minimum diameter of the eye as measured with the head in full lateral aspect."  I think that means the horizontal distance across the eye, which is usually the shortest (as compared to the vertical distance, which would be the longest).  That may help you with your ID's if I'm right.

 

Where did you see that? Everything I have read defines MOD as Maximum Ocular Diameter, which is the largest diameter in any direction.

 

http://biostor.org/r...ence/95394.text

http://www.asu.edu/c...ym Res 2009.pdf

 

 

Edit: I found it. So it seems it means "Maximum Ocular Diameter" AND "Minimum Ocular Diameter". That should work well when keying out ants. I think I may have a question for the Myrmecologists Facebook group.

Edited by dspdrew, July 28 2015 - 6:37 AM.

[kellakk]

Well that's annoying. Probably best to go by how it's defined in the key that you're using though. It seems that R. Snelling defined MOD as minimum ocular diameter, while other authors have defined it as maximum Richland diameter.

[dspdrew]

He defined it in the key? I have been using the copy on AntWiki. AntWiki has a list of measurement acronyms, but doesn't include MOD.

[kellakk]

Yup, check the left column on the bottom of page 22.

[dspdrew]

Just got some new pictures of another queen.