Megalomyrmex poatan

Megalomyrmex poatan was described from a unique worker recovered from a leaf litter sample collected in San Pedro de la Sierra, Magdalena, Colombia submitted to Berlese. I received from the MCZ a second sample of this species, including 12 workers and one gyne (description below) from 15 Km north of Puerto Maldonado, Tambopata Province, Cuzco Amazonico, Peru, collected by S.P. Cover and J. Tobin (CA-27), elevation 200 m (12°36’S, 69°11’W). Three subsamples, including respectively three, two and one worker bear distinctive labels that read: “Camp. sifted litter from compost pile by trail to zone 1; Camp. in compost pile under bananas at forest edge, berlesate # 148; and seasonally flooded forest, plot ZUZI, flower fall, berlesate # 468”. (Brandão 2003)

Identification
Brandão (1990) - The sculpture pattern, head shape and the deeply excavated metanotal groove clearly distinguish this species from all other Megalomyrmex.

Distribution based on Regional Taxon Lists
Neotropical Region: Colombia, Peru.

Nomenclature

 *  poatan. Megalomyrmex poatan Brandão, 1990: 443, figs. 99, 100 (w.) COLOMBIA. Brandão, 2003: 154 (q.).

Worker
Mandibles smooth: dental formula 2+6: palpal formula 3:2: median area of clypeus depressed, but not marked by lateral carinae: anterior clypeal border without a clearly defined denticle: region between compound eyes and antennal sockets with concentric sculptures: 10 ocular facets at compound eyes largest diameter: occi­pital margin not raised; promesonotal suture not impressed dorsally, promesonotum profile con­tinuous: metanotal groove very deep and wide; base of dorsal face of propodeum higher than the metanotum in side view; katepistemum smooth: dorsal face and declivity indistinct; declivity with rugosities over the foramen; non-peduncula­ te petiole with anteventral denticle followed by a series of transversal rugosities covering the who­le ventral face; posterior slope of petiolar node rugose: postpetiole lower and broader than the petiole with ventral process small and globose.

Pilosity: only long hairs (ca. .2mm) all  over the body surface. more common at dorsum, legs and scapes.

Color: bright reddish-brown with yellowish club of funiculus, coxae and trochanters.

Queen
Brandão (2003) - Three equally developed ocelli; mesonotum with parapsidal sutures but no notaulus; katepisternum distally rugose, the rugae continuing through the metapleura; propodeum dorsal face and declivity continuous and completely covered by rugosities, similar to those found in the workers; petiole with a series of transverse rugosities covering the whole ventral face, at the distal end of the petiole, the rugosities cover also the lateral faces, but do not reach the apex; the postpetiole posterodorsal face has one continuous rugosity just before the socket, although the rugosities are absent on the ventral face.

Type Material
San Pedro de la Sierra, Pico Yerbabuena (1730 m), Magdalena, Colombia (05°33'N, 74°37'W). The type was collected by C. Kugler from a Berlesate sample (Feb, 18 1977). Holotype at Museum of Comparative Zoology, Harvard.

Etymology
The characteristic head shape led me to use the name poatan, straight head in Tupi.