Megalomyrmex goeldii

With the assistance of Jorge Diniz I collected 4 colonies of M. goeldii in Petropolis under stones, within rotten logs and litter. Population sizes ranged from 300-400 workers, 1 to 4 dealate queens and all stages of immatures. (Brandão 1990)

Identification
Brandão (1990) - Non-type specimens may present the lateral portions of clypeus and antennal sockets faintly sculptured. Also some individuals present a long, narrow and translucid flange at the ventral face of petiole enclosing or not at its anterior end a small denticle. Specimens from Varginha and Santos Dumont (MG, Brasil) always present the anterior denticle, while in other localities this may be wanting. At the southern end of M. goeldii distribution (state of Sao Paulo) the epipetiolar carina is not complete over the foramen. Workers from Petropolis have the scarser pilosity from all samples.

Distribution based on Regional Taxon Lists
Neotropical Region: Brazil.

Biology
Brandão (2003) - J. Delabie, sent me from a sample of M. goeldii, including workers and several “ergatoid” females collected in an old cocoa plantation located at Km 22 of the Itabuna-Ilhéus road (14 48’S, 39°16’W), Bahia state, Brazil. Reproductives are larger and darker than conspecific workers, and retain only the anterior median ocellus (as do ordinary gynes of this species), lacking any vestiges or scars of the lateral ones. Their mesonotuns bear a transverse impression (in side view) and the metanotuns can be clearly differentiated from other sclerites. The dorsal area of the anepisternuns and lateral margins of the katepisternuns bear rugulae.

I failed to notice any difference between workers of this sample and those of queenright colonies workers from southern localities. It is interesting to note that these are the only colonies from which ergatoids are known, and they come from the periphery of the species distribution, northern in this case.

Later on, J. Diniz visited the same locality (but in a specific location called Parque Zoobotânico) and found a Megalomyrmex goeldii colony with several ergatoids (voucher workers at MZSP). Unfortunately, we do not know if all of them were inseminated, as is the case for many other Megalomyrmex species. Queenright colonies from southern localities may have several inseminated dealated gynes (see Brandão, 1990:424). I studied, from the same locality but unfortunately not from the same colony series, seven males collected by P. Terra in March 3, 1988 (# 4587). In these specimens the pronotum is strongly depressed, representing one extreme of the tendency already noticed in southern samples.

Jones et al. (1999) compared the amount of different venom alkaloids present in M. goeldii ergatoid gynes and workers.

In July 1987, I collected 30 foraging workers of M. goeldii on a rotten stump in a dense evergreen primary Atlantic Forest reserve, Parque Municipal Baepi, Ilha de São Sebastião, São Paulo state, Brazil, 500 m of altitude (23°50’S, 45°18’W). Although I failed to locate the nest, this sample helped to confirm that, in workers from the southern end of the species distribution, the epipetiolar carina is not complete over the foramen (Brandão, 1990:424).

From the Los Angeles County Museum (LACM), I received three workers of M. goeldii from “Brazil” mounted on one pin, from the U.S. Quarantine at Hoboken, New Jersey, collected in July 16, 1947 by McMaster & Adams in wild Cattleya purpurata (# 47-10233).

I studied three workers of M. goeldii collected by M. Queiroz in a coffee plantation in Viçosa, Minas Gerais state, Brazil, in April 26, 1988 (20°45’S, 42°53’W), deposited in the MZSP. Soares et al. (1998) collected M. goeldii visiting sardine/honey baits set in a secondary growth semideciduous forest in the same locality.

Megalomyrmex goeldii seems to be fairly common in the localities where it has been recorded, but populations seem to be widely scattered. This may be related to the fact that in some populations of this species, the female reproductives are ergatoids, and hence dispersion is severely limited. These ants are easily attracted to baits, so it may be reasonable to conclude that they do not occur in places where they have never been found using baits. However, Yamamoto (1999) surveyed the litter ant fauna in the Estação Biológica de Boracéia, Salesópolis, São Paulo state, Brazil (23°39’26”S, 45°53’36”W), 843 m above sea level, an Atlantic Forest reserve pertaining to the MZSP. The author collected 132 individually sifted 1 m2 litter samples submitted to Winkler extractors, obtaining a total of 95 ant species in 1304 records (record in this case means a species recorded in a given sample). M. goeldii was recorded 14 times in the survey (1.1% of all records), in a locality previously surveyed by several ant researchers and where specimens of M. goeldii were never found so far. Notwithstanding, Megalomyrmex iheringi has not been found recently in the E.B. Boracéia, a locality where it was still fairly common in the beginning of the twentieth century.

As part of an ongoing leaf litter ant fauna survey along the Atlantic forest, financed by FAPESP, A.A. Tavares (2002) collected 50 individually sifted 1 m2 litter samples submitted to Winkler extractors for 48 hours, in Ribeirão Grande, Parque Estadual Intervales, Base Barra Grande, São Paulo state, Brazil, in February 5, 1999. Megalomyrmex goeldii was recorded four times in the survey. In Parque Estadual Serra do Mar, Núcleo Cunha-Indaiá Cunha, São Paulo state, Brazil (23°15’03”S, 45°00’26”W), Tavares repeated the procedure and recorded M. goeldii 20 times. The species seems to be one of the most common litter inhabiting ants in these localities.

Castes
Both ergatoid and winged queens have been recorded in separate populations of M. goeldii (Brandao 2003)

Nomenclature

 *  goeldii. Megalomyrmex goeldii Forel, 1912g: 14 (w.) BRAZIL. Wheeler, W.M. 1925a: 29 (m.); Borgmeier, 1930: 34 (q.). See also: Brandão, 1990: 423.

Worker
Brandão (1990) - Mandibles smooth; clypeus not carinate with anteromedium denticle; frontal suture not impressed; 3-segrnented antennal club; occipital margin not raised: pronotal elevation low, promesonotal suture faintly impressed dorsally: mesosternum and metasternum without ventral processes; dorsal face and declivity of propodeum meeting in smooth angle; declivity smooth; ventral face of petiole in general not denticulate nor laminate; postpetiole ventral face with a round and not very prominent process.

Pilosity: long hairs (ca. .2mm) at clypeus, frontal carina, vertex, dorsal faces of petiolar and postpetiolar nodes and gaster apex. Small hairs (ca. 1mm) at mandibles, antennae, sides of head, legs and basal segments of gaster.

Color: uniformly shinny yellow-brown, mandible teeth brown.

Male
Brandão (1990) - To Wheeler's original description of M. goeldii males I should add that the scape is slightly shorter than the head capsule, the mesonotum does not have notaulus nor parapsidal sutures and the epipetiolar carina is not complete over the foramen. Rs and Mf3 are well developed (called branches of cubitus by Wheeler).

Borgmeier (1930) described the female caste from a specimen collected among rotten leaves in Petropolis, RJ, Brasil. I compared this specimens with the other 5 available and noticed that in all of them the posterior ocelli are vestigal, the mesonotum has no impression at all and the dorsal face of the propodeum is longitudinally depressed. A queen from Redencao da Serra, SP, Brasil presents a flange ventral to be petiole but no denticle nor the acute tooth under the postpetiole, which might be abraded.

Ettershank (1966) figure of female's wings, although identical to the male wings I have in hand, may not belong to this species, as the specimen he figured came from Manaus, a locality farther north from the known distribution of M. goeldii.

Type Material
Brandão (1990) - Colonia Alpina (munic. Teresopo lis), RJ, Brasil (22°26'S, 42°59'W). Lectotype designation Lectotype and paralectotype Museum de la Ville de Geneve, paralectotype Naturhistorisches Museum Basel, paralectotype Museu de Zoologia USP.