Megalomyrmex ayri

Specimens collected by W. L. Brown Jr. at Faz. Junqueira Vilela came from a nest collected at 3 km east of the farm house in the forest. The paratypes from Vilhena came from a polygynous colony found by Dra. Ana Harada within the litter near a small stream in the forest. (Brandão 1990)

Identification
Workers from Megalomyrmex goeldii and M. ayri are very similar, but the shape of the clypeus and size clearly separate them. Queens are more di­verse and can be distinguished by the ocelli (only the anterior one is developed in M . goeldii) and by the given measurements.

Distribution based on Regional Taxon Lists
Neotropical Region: Brazil.

Biology
Brandão (2003) - Dr. Heraldo Vasconcellos collected two workers of Megalomyrmex ayri at Km 72, BR 174, Manaus, Amazonas state, Brazil (03°08’S, 60°01’W), in March 1990 (# 4642). A.B. Casimiro collected a worker and a gyne of M. ayri also in Manaus (# 4832 – Rs 2108 – E3). These are the first records of the species in Central Amazon, and the first records after the description of the species by Brandão (1990). Regarding the Modestus species group, only Megalomyrmex wallacei was previously recorded in the Amazonian basin. Megalomyrmex ayri appears to be uncommon in Manaus, as this locality has been intensively collected in recent years by several colleagues, and only these two samples have turned up thus far.

J. Delabie (CEPLAC, Itabuna, Bahia state, Brazil) sent me for study material collected in three localities in eastern Bahia state, Brazil: 3 alate gynes and a worker (# 4733) in Cachoeira, collected by G. Santos, in December 11, 1993, a worker from Ubatã (14°13’32”S, 39°27’56”W), collected by J.C.S. Carmo in December 27, 1996, and a worker from Ilhéus (# 4544B), collected by A.B. Casimiro in August 25, 1992. Workers of these three samples fit the definition of M. ayri since they show a clear suture between anepisternun and katepisternun. However, the Cachoeira gynes are problematically assigned as they present smooth mandibles. Also all other M. ayri samples come from Amazonian localities. For this reason, it is preferable to wait for more Bahian material before applying a name to these samples.

Nomenclature

 *  ayri. Megalomyrmex ayri Brandão, 1990: 420, figs. 1, 12, 26, 36 (w.q.) BRAZIL.

Worker
Mandibles smooth, clypeus with concave an­terior border between the feeble carinae, that delimit a median depression; promesonotal su­ture impressed dorsally; faces of propodeum meeting in a gentle angle; declivity either smooth or with one rugosity around the foramen; ventral face of petiole with anterior denticle and a longi­ tudinal translucid flange; dorsal margin of petio­lar node slope straight in side view; ventral face of postpetiole with a small globose process.

Pilosity: Long hairs (more than .2mm)  all over the body surface; except mandibles, legs and posterior faces of petiole and postpetiole. Small hairs (ca. .1 mm) at mandibles, legs and head.

Color: yellowish-brown.

Queen
Mandibles finely striate; ocelli equally devel­ oped; notaulus and parapsidal sutures impressed; dorsal face and declivity of propodeum meeting by means of lateral tubercles confining a shallow median depression; postpetiole with laterally produced spiracles and ventral face with rugosi­ ties at its posterior  end.

Pilosity: Only long hairs (same as workers) more profuse than in conspecific workers.

Type Material
Type Loc.: Utiariti, Rio Papagaio, MT, Brasil (13° 02'S, 58° 17'W). Holotype and 20 paratypes; Faz. Junqueira Vilela, munic. Diamantino, MT, Brasil (14° 25'S, 56° 26'W), 10 paratypes; Sinop, MT, Brasil (12" 31'S. 55" 37'W), 3 paratypes; Vilhena, RO, Brasil ( 12° 43'S. 60° 07'W), 29 paratypes.

Holotype (worker) and 11 paratypes (1 queen, 10 workers) from Utiariti, 3 paratypes (worker) from Sinop, 6 ( 1 queen, 5 workers) from Junqueira Vilela and 10 (2 queens, 8 workers) from Vilhena at Museu de Zoologia da USP: 4 paratypes (workers) from Utiariti, 2 (workers) from Junqueira Vilela and 2 (workers) from Vilhena at British Museum of Natural History; 5 paratypes (workers) from Utiariti, 2 (workers) from Junqueira Vilela and 3 (workers) from Vilhena at Museum of Comparative Zoology; 14 paratypes (2 queens, 12 workers) from Vilhena at Instituto Nacional de Pesquisas da Amazonia, Manaus.

Kempf already noticed that the specimens collected in Utiariti might belong to a new species. Accordingly he labelled them as: “Megalomyrmex pr. goeldii, talvez n. sp., W.W. Kempf det.”

Etymology
The name ayri means small in Tupi, referring to the workers of this species, relatively smaller than Megalomyrmex goeldii workers.