Mycetomoellerius compactus

Known only from the holotype worker. Mayhé-Nunes & Brandão (2002) - We have found the following information in Kempf (1961) regarding the type locality: “primary forest on sand, slope of the hill,” located “about 130 Km south of Paramaribo, in the interior, on the eastern side of Sarakreek near Dam.”

Identification
Mayhé-Nunes & Brandão (2002) - Differs from Mycetomoellerius dichrous by being unicolored, of much smaller size, by having the frontal lobes rounded and much more expanded laterad, shorter antennal scapes, better developed supraocular tumulus and paired carinae on vertex; the lateral pronotal spines are higher than the anterior mesonotal ones, and the gaster is distinctly marginate on sides. The differences from Mycetomoellerius opulentus and Mycetomoellerius relictus are as follows: anteroinferior corner of pronotum not angular nor dentate, but rounded; second pair of mesonotal projections very low; postero-dorsal border of postpetiole broadly excised.

Distribution based on Regional Taxon Lists
Neotropical Region: Brazil, Suriname.

Castes
Known only from the worker caste.

Nomenclature

 *  compactus. Trachymyrmex compactus Mayhé-Nunes & Brandão, 2002: 673, figs. 2-4 (w.) SURINAM.
 * Combination in Mycetomoellerius: Solomon et al., 2019: 948.

Worker
TL 3.8; HL 0 .86; HW 0.86; IFW0.57; ScL0.73; TrL 1.21; WL 1.21; HfL0.97. Medium brown, head more reddish brown. Integument finely and indistinctly shagreened, opaque. Body and appendages clothed with more or less curved, oblique to decumbent hairs of variable length, longest on clypeus, occiput, dorsum of alitrunk, petiole, postpetiole and tergum I of gaster. Trunk hairs arising from more or less prominent piligerous tubercles. Fine and dense pubescence appressed on antennae and legs, suberect or strongly curved elsewhere. quite distinct on tergum I of gaster. but never masking the integument.

Head. Mandibles smooth and shining except laterally on base where they are finely transversely striate. and near the masticatory margin, which bears with an apical tooth and approximately 8 regularly developed teeth. Clypeus with a pair of minute teeth, each arising near the base of the frontal lobes. Frontal lobes semicircular. lateral borders strongly crenate, strongly expanded laterad, the interfrontal width exceeding one half of the head width across the eyes. Frontal carinae diverging caudad, fading out a little before the apex of scrobe. Front and vertex irregularly to longitudinally rugulose, without isolated piligerous tubercles. Preocular carinae not curving mesad above eyes, but extending strictly caudad, fading out halfway between posterior orbit of eyes and apex of scrobe. Posterior third of antennal scrobe vestigially delimited, its apex only slightly projecting in a tuberous fashion. Supraocular tumulus vestigial; occipital corners angular and dentate in full-face view. Occiput shallowly notched in the middle. Carinae of vertex vestigial. Occipital tooth absent. Inferior occipital corner indistinctly marginate or rounded. Eyes moderately convex, not more than l0 facets in a row across the greatest diameter. Antennal scapes shorter than head capsule. only shortly surpassing the occipital corner when laid back over head as much as possible. Funicular segments II-VIII slightly longer than broad.

Alitrunk covered by more or less prominent piligerous tubercles. Pronotum with an indistinct humeral angle, its anteroinferior corners rounded, the lateral spines pointed. Mesonotum with both the first and second pair of dorsal projections very low, the third pair represented by minute teeth. Alitrunk constricted dorsa-laterally at the deeply impressed metanotal groove. Basal face of propodeum narrow, laterally delimited by a row of tubercles; propodeal spines low, about as high as the lateral pronotal spines. Hind femora shorter than length of alitrunk.

Waist and gaster. Petiole pedunculate, the node proper a bit longer than broad, lacking a dorsal armature; supetiolar process absent. Postpetiole broader than long, shallowly excavate above with a deep excision on the postero-dorsa1 border, the postero-lateral corners slightly tuberous. Gaster opaque with dense. minute piligerous tubercles rather evenly distributed. Tergum I of gaster laterally sharply marginate and ridged in almost the entire length.

Type Material
Holotype: Worker, SURINAME: Maripaheuvel, [September] 1959, J. van der Drift col. (WWK 14-X:X:-15). We were not able to secure coordinates for this locality in the several printed and electronic consulted gazetteers.

Etymology
The name was chosen by Kempf in reference to the alitrunk of this species, which is more compact than in other species of the opulentus group.

References based on Global Ant Biodiversity Informatics

 * Franco W., N. Ladino, J. H. C. Delabie, A. Dejean, J. Orivel, M. Fichaux, S. Groc, M. Leponce, and R. M. Feitosa. 2019. First checklist of the ants (Hymenoptera: Formicidae) of French Guiana. Zootaxa 4674(5): 509-543.
 * Groc S., J. H. C. Delabie, F. Fernandez, F. Petitclerc, B. Corbara, M. Leponce, R. Cereghino, and A. Dejean. 2017. Litter-dwelling ants as bioindicators to gauge the sustainability of small arboreal monocultures embedded in the Amazonian rainforest. Ecological Indicators 82: 43-49.
 * Groc S., J. H. C. Delabie, F. Fernandez, M. Leponce, J. Orivel, R. Silvestre, Heraldo L. Vasconcelos, and A. Dejean. 2013. Leaf-litter ant communities (Hymenoptera: Formicidae) in a pristine Guianese rainforest: stable functional structure versus high species turnover. Myrmecological News 19: 43-51.
 * Klingenberg, C. and C.R.F. Brandao. 2005. The type specimens of fungus growing ants, Attini (Hymenoptera, Formicidae, Myrmicinae) deposited in the Museu de Zoologia da Universidade de Sao Paulo, Brazil. Papeis Avulsos de Zoologia 45(4):41-50