Aphaenogaster azteca Enzmann, J. 1947

Shattuck, Steve & Cover, Stefan, 2016, Taxonomy of some little-understood North American ants (Hymenoptera: Formicidae), Zootaxa 4175 (1), pp. 10-22 : 12-13

Aphaenogaster azteca Enzmann, J. 1947 , new status

Aphaenogaster fulva azteca Enzmann, J. 1947: 150 . Syntype workers, Mexico (Museo Civico di Storia Naturale, Genoa) [https://www.antweb.org/specimen/CASENT0904168]. Raised to species.

Emery (1895) established the infrasubspecific (and therefore unavailable) name “ Stenamma (Aphaenogaster) fulvum subsp. aquia var. aztecum ” for several workers from Mexico (specific locality not given and currently unknown). Enzmann (1947) was the first to use this name as a trinomial and thereby made the name available as Aphaenogaster fulva azteca . Emery (1895) separated his variety from others based on its very “rough” sculpturing, long and almost horizontal propodeal spines and dark black-brown body color with bright red legs. An image of a syntype is available on AntWeb (at www.antweb.org/specimen/CASENT0904168) and single worker labeled as “ Aphaenogaster fulvum aquia var. aztecum Em , Mexico ” and “from Emery ” and matching Emery’s description is held in the MCZC. While not labeled as a type it seems highly likely that if not a true type this specimen was certainly identified by Emery and is likely to be conspecific with the true type material.

When comparing Emery’s specimen of A. azteca with A. fulva specimens, similar body color and development of sculpturing can be found in A. fulva specimens. However, darker A. fulva workers also have darker legs, which are similar in color to the body. In contrast, the legs in A. azteca are distinctly lighter in color compared to the body. Also, as noted by Emery, the propodeal spines in A. azteca are directed posteriorly (are nearly horizontal) while in A. fulva these spines are directed strongly upwards. These last two characters readily separate these two taxa. Finally, A. fulva is most abundant in the eastern and southeastern US although it is known from as far west as New Mexico (a doubtful record) and eastern Texas, but has been only rarely encountered there. A. azteca was collected from an unknown locality in Mexico, an area where A. fulva does not occur, or at least not commonly. These morphological and geographic differences strongly suggest that these two taxa are both distinct and we propose raising A. azteca to full species status.