4 replies to this topic

[Canadian anter]

How do you tell them apart!!!

[kellakk]

I have no experience with Myrmica. That said, Aphaenogaster seem much more narrow and elongated than Myrmica, which seem more squat and rounded.  There are actual morphological differences detailed in the scientific literature, but with the naked eye I think those will be the most obvious differences.

[LC3]

Here's a list of some characteristics I noticed of Aphaenogaster compared to Myrmica:

Aphaenogaster of North America are more slender than Myrmica, have longer legs with an elongated head. Aphaenogaster have a distinctly concave thorax that curves in or is sloped upwards from the gaster as opposed to Myrmica with a flatter thorax with 2 bulges, Like Tetramorium, Myrmica don't have a really elongated head, their head shape is somewhat of a circly square.  Also nearly all species Myrmica are covered in ridges (except for the gaster). The petiole nodes for Apheanogaster are more pointy as well, in the case of subterranean species like A.occidentalis they're round looking. For Myrmica the second petiole node is larger and less pointed than the first node with the first node usually looking like a spike pointing inward.

 

Now for the queen's, Apheanogaster queens have a much bulkier thorax than Myrmica, sometimes very smooth. Just like the workers, the queen's thorax is sloped, making the back of the thorax nearly vertical. The thorax of most Myrmica queens are less bulky and their gasters aren't too big either. I think Aphaenogaster have larger gasters than Myrmica as well.

[Canadian anter]

Which is bigger?

[kellakk]

I think it might depend on species.  What you can do is look at the profile images of each species on AntWeb and use their scale to tell about how long each species is. For example, looking at this Myrmica americana worker you can see that it's 3-4 mm long.