Introduction
Brachymyrmex is a New World genus whose members are minute, soft-bodied, have a small petiolar scale, and a nine segmented antenna without a club. Workers have well developed eyes. Color ranges from pale light-yellow to dark brown. Species is this genus usually nest in soil or rotting wood. This group is in drastic need of revision.

Identification

Brachymyrmex obscurior is a small yellowish-brown to brown species with similarly colored appendages. The promesonotum usually has four or more erect hairs. The gaster has dense, appressed pubescense. The head is longer than wide. The eyes are relatively small; much shorter than the length of the malar space. The scape surpasses the occipital border.

Brachymyrmex obscurior is most similar to B. patagonicus Mayr, another exotic species. It differs in the size of the eye, which is much smaller in B. obscurior than in B. patagonicus, and in the much denser pubescence, especially on the gaster. Additionally, the males of these two species are quite different in color. Males of B. obscurior are concolorous dark brown; whereas males of B. patagonicus are bicolored with the head and gaster dark brown and the rest of the body, including the appendages, being pale yellowish-brown. Brachymyrmex sp.-01, recorded from Florida, is also dark brown in color, but lacks erect hairs on the body. Another similar species, not yet reported from the U.S., but possible, is B. heeri. This brownish colored species differs in that the workers lack ocelli and have sparse pubescence similar to B. patagonicus. An undescribed brown species known only from two queens collected from Arkansas (Lloyd Davis, pers. comm.) is unusual in that the queens are tiny, about the size of typical workers. All other known species present in this region are yellowish in color. Other species of Brachymyrmex in our region are yellow.

Biology and Economic Importance

Distribution
Brachymyrmex obscurior is thought to be an exotic species native to Central America and South America. Although this species is very common in southern FL, it is only known from one locality so far in southern MS.

Literature Cited

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