Anochetus mayri

Brown, WL Jr.,, 1978, Contributions toward a reclassification of the Formicidae. Part VI. Ponerinae, tribe Ponerini, subtribe Odontomachiti. Section B. Genus Anochetus and bibliography., Studia Entomologica 20, pp. 549-638 : 617-619

[41] Anochetus mayri

Anochetus of the mayri complex are the common small members of the genus in the New World, corresponding to A. katonae in Africa, and perhaps to A. graeffei in the Indo-Australian region. Like these species, A. mayri is variable in body size, eye size, antenna! scape length, color and sculpture, as well as size and details of form and dentition of the mandibles. It is not always easily separated from smaller specimens of the inermis complex on the one hand, or from neglectus on the other, and some of the variation raises the suspicion that mayri may include two or more sibling species.

A. mayri was first proposed in a key, without a proper description, from a specimen from St. Thomas ' in the West Indies. It was never described in full by Emery, so when Wheeler described the subspecies laeviuscula , he did not know what the «typical» mayri was like. In fact, we still have no clear idea of what the color, sculpture, etc, of the mayri type really are, owing to the present difficulties of studying the material of the Emery Collection in Genoa. But we do know that the mayri complex is widespread in the West Indies and shows there wide variation in size, color and sculpture, including samples with predominantly smooth and some with completely striate pronota, as well as intermediates. After prolonged study of this material, I cannot find any way to separate it into two species, or even into reasonably clearcut geographical forms, so I assume that mayri and laeviusculus are synonyms.

On the mainland, the situation is more complex, because the variation is more extensive. The Atlantic lowland forest of Costa Rica, for example, contains a larger, dark brown form (HL 1.05- 1.08, HW 0.92-0.94, ML 0.57-0.58, eye L 0.13 mm) with punctulate-striate sculpture weak in the middle of the pronotum, and weakly shining, but still not completely smooth. Sympatric in this area (for instance, at Rio Toro Amarillo, near Guapiles, Limon Prov.) is a smaller (HL 0.93, HW 0.82, ML 0.48, eye L 0.10-0.11 mm) brown- ish-yellow phenon with completely longitudinally striate pronotum. Whether these forms are conspecific or not cannot be decided without more evidence from this locality, but there are available intermediates among samples from elsewhere in the range, which extends from the Veracruz lowlands of Mexico through Central America and the West Indies to hylean South America, at least as far south as the Beni River drainage of Bolivia, and on the west slope of the Andes to southern Ecuador.

South and east of the Amazon drainage in Brazil occurs a rather uniform mayri-complex phenon that is usually dull yellowish-brown in color, has finely striolate cephalic dorsum and sericeous-striolate or densely punctulate pronotum (the striation barely resolved at 50X). This form, which closely resembles certain variants from the West Indies, corresponds to the named varieties or subspecies neglectus , australis and nobilis , which I regard as synonyms. My instincts are to extend the synonymy by placing all 3 names under mayri , since no satisfactory characters have been found to separate neglectus from all samples of mayri , and this would be the preferred action here were it not for two stubborn facts:

First, the neglectus phenon is widespread and the only form over a wide area of central and southern Brazil, Uruguay and northern Argentina (and presumably Paraguay). It ranges at least from Pernambuco (Caruaru, B. Pickel), [central?] Mato Grosso, and Minas Gerais (Belo Horizonte, J. C. Bradley) southward to Santa Fé Prov. in N central Argentina. Over this range, the eyes are relatively fairly large (eye L 0.13-0.16 mm), and the mesopleura are sculptured throughout, though their lower middle portions are slightly shining. Most similar samples from the Caribbean area have smooth, shining areas on the mesopleura, and the eyes are smaller.

Second, several males of undoubted Anochetus taken at light on 14 Nov. 1964 at Piracicaba, São Paulo State (C. Triplehorn), and about the right size to match mayri-complex workers, have terminalia radically different from those of males (figs. 70, 71) associated with mayri-complex workers taken in a nest from near Turrialba, Costa Rica (W. L. Brown). Males taken at light during June 1975 at Tinalandia, on the western slope of the Andes in Pichincha Prov., Ecuador (S. and J. Peck) are very similar to the Turrialba sample, at least as seen undissected. The Piracicaba males have broad-based, convex parameres that are suddenly constricted near midlength, and then each is continued as a slender, lanceolate, apical blade that is weakly concave facing laterad, so that when the terminalia are viewed end-on, the parameral apices are curved slightly away from the midline. The volsellae are also longer in the Piracicaba males, but the sharp apices of the aedeagal valves are shorter than those of the northern males.

We do not know for sure, of course, what kind of workers belong with the Piracicaba males, but the only right-sized workers that we know to occur in the area are those I call here neglectus . As long as there is a chance that these southern males do belong with neglectus workers, it will be necessary to recognize the latter name, even in the absence of absolute diagnostic characters for workers and queens.

As in other groups of Anochetus , the mayri complex will not be completely clarified until we have adequate samples of workers or queens associated in the nest with males.

A. mayri is found mostly in forests under stones, in moss on rocks or logs, in rotten twigs on the forest floor, or in larger bodies of rotten wood. The workers and queen feign death, and are difficult to see.