Apterostigma megacephala

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Apterostigma megacephala
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Apterostigma
Species: A. megacephala
Binomial name
Apterostigma megacephala
Lattke, 1999

Apterostigma megacephala F1.jpg

Collection data for all specimens indicate this species is found in lowland mesic forests. Although only four workers have been found, it is probably safe to assume that this species is monomorphic, given the small variation in measurements of the studied specimens and the basal position of the group within Attini. Only more derived attines, such as Acromyrmex and Atta, are polymorphic. (Lattke 1999)


Lattke (1999) - Flattened compound eyes partially wrapped around conical tubercles, ommatidia reduced; mesonotal denticles present; erect rigid pilosity present on head, mesosoma and gaster; erect hairs with spatulate apices frequently present on mesosoma.


Latitudinal Distribution Pattern

Latitudinal Range: 6.06321° to -13.0766°.

Tropical South

Distribution based on Regional Taxon Lists

Neotropical Region: Colombia, Peru (type locality).

Distribution based on AntMaps


Distribution based on AntWeb specimens

Check data from AntWeb

Countries Occupied

Number of countries occupied by this species based on AntWiki Regional Taxon Lists. In general, fewer countries occupied indicates a narrower range, while more countries indicates a more widespread species.

Estimated Abundance

Relative abundance based on number of AntMaps records per species (this species within the purple bar). Fewer records (to the left) indicates a less abundant/encountered species while more records (to the right) indicates more abundant/encountered species.


Explore-icon.png Explore Fungus Growing 
For additional details see Fungus growing ants.

A handful of ant species (approx. 275 out of the known 15,000 species) have developed the ability to cultivate fungus within their nests. In most species the fungus is used as the sole food source for the larvae and is an important resource for the adults as well. Additionally, in a limited number of cases, the fungus is used to construct part of the nest structure but is not as a food source.

These fungus-feeding species are limited to North and South America, extending from the pine barrens of New Jersey, United States, in the north (Trachymyrmex septentrionalis) to the cold deserts in Argentina in the south (several species of Acromyrmex). Species that use fungi in nest construction are known from Europe and Africa (a few species in the genera Crematogaster, Lasius).

The details of fungal cultivation are rich and complex. First, a wide variety of materials are used as substrate for fungus cultivating. The so-called lower genera include species that prefer dead vegetation, seeds, flowers, fruits, insect corpses, and feces, which are collected in the vicinity of their nests. The higher genera include non leaf-cutting species that collect mostly fallen leaflets, fruit, and flowers, as well as the leafcutters that collect fresh leaves from shrubs and trees. Second, while the majority of fungi that are farmed by fungus-feeding ants belong to the family Lepiotaceae, mostly the genera Leucoagaricus and Leucocoprinus, other fungi are also involved. Some species utilise fungi in the family Tricholomataceae while a few others cultivate yeast. The fungi used by the higher genera no longer produce spores. Their fungi produce nutritious and swollen hyphal tips (gongylidia) that grow in bundles called staphylae, to specifically feed the ants. Finally, colony size varies tremendously among these ants. Lower taxa mostly live in inconspicuous nests with 100–1000 individuals and relatively small fungus gardens. Higher taxa, in contrast, live in colonies made of 5–10 million ants that live and work within hundreds of interconnected fungus-bearing chambers in huge subterranean nests. Some colonies are so large, they can be seen from satellite photos, measuring up to 600 m3.

Based on these habits, and taking phylogenetic information into consideration, these ants can be divided into six biologically distinct agricultural systems (with a list of genera involved in each category):

Nest Construction

A limited number of species that use fungi in the construction of their nests.

Lower Agriculture

Practiced by species in the majority of fungus-feeding genera, including those thought to retain more primitive features, which cultivate a wide range of fungal species in the tribe Leucocoprineae.

Coral Fungus Agriculture

Practiced by species in the Apterostigma pilosum species-group, which cultivate fungi within the Pterulaceae.

Yeast Agriculture

Practiced by species within the Cyphomyrmex rimosus species-group, which cultivate a distinct clade of leucocoprineaceous fungi derived from the lower attine fungi.

Generalized Higher Agriculture

Practiced by species in several genera of non-leaf-cutting "higher attine" ants, which cultivate a distinct clade of leucocoprineaceous fungi separately derived from the lower attine fungi.

Leaf-Cutter Agriculture

A subdivision of higher attine agriculture practiced by species within several ecologically dominant genera, which cultivate a single highly derived species of higher attine fungus.

Note that the farming habits of Mycetagroicus (4 species) are unknown. Also, while species of Pseudoatta (2 species) are closely related to the fungus-feeding genus Acromyrmex, they are social parasites, living in the nests of their hosts and are not actively involved in fungus growing. ‎



The following information is derived from Barry Bolton's Online Catalogue of the Ants of the World.

  • megacephala. Apterostigma megacephala Lattke, 1999: 2, figs. 1, 2 (w.) PERU, COLOMBIA.
    • Type-material: holotype worker, 3 paratype workers.
    • Type-locality: holotype Peru: Madre de Dios, Cuzco Amazónico, 15 km. NE Puerto Maldonado, Rio Tambopata, 200 m., 21.vi.1989, CA-357, Plot 1E 24 (S.P. Cover & J.E. Tobin); paratypes: 1 worker Peru: Madre de Dios, Estación Pakitza-Manu, 13-17.ii.1992 (R. Combra & D. Quintero), 1 worker Madre de Dios, Manu Reserve Zone, Pakitza Station, x.1988 (J. Tobin), 1 worker Colombia: Meta, Parque Natural Nacional La Macarena, ix.1990 (M.T. Barreto).
    • Type-depositories: MCZC (holotype); CPDC, ICNB, MIZA (paratypes).
    • Status as species: Bezděčková, et al. 2015: 115; Fernández & Serna, 2019: 839.
    • Distribution: Colombia, Peru.

Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.


Lattke 1999. Figure 3. Anteromedian clypeal area and inner posterior mandibular corners. Median clypeal seta visible as the most robust hair present.


Holotype (UNCB-CPDC paratypes): HL 1.69 (1.70-1.64); HW 1.44 (1.51-1.46); LW 0.90 (0.94-0.91); ML 0.90 (1.06-1.02); SL 1.47 (1.64-1.54); LM 2.49 (2.51-2.47) mm. CI 0.85 (0.89-0.89); SI 1.02 (1.09-1.05). Head in frontal view subquadrate, anterior clypeal border broadly convex, medially bluntly angulate or with blunt short denticle; sides slightly diverging posterad, posterolaterally convex and with straight posteromedian border. Clypeus anteriorly with narrow, longitudinal band of smooth and shiny integument, remainder opaque, rugose; prominent median seta usually present on anterior edge, thicker and longer than surrounding hairs. Clypeus medially with carinae forming Y-shaped ridge, each posterior arm stems from below frontal lobe, with anterior arm extending to posterior edge of shiny strip. Clypeus posterolaterally bound by ridge extending from frontal lobe, separating it from antennal fossae; each ridge then extends posterad, bordering antennal fossa laterally and joining rugae on cephalic dorsum just below level of eye. Frontal lobes relatively massive and subtriangular, with bluntly rounded apex, very short anterior margin, very broadly convex lateral margin and approximately straight posterior margin; dorsal surface with coarse longitudinally arching rugae. Frontal carinae extending posterad only to upper level of eyes, afterwards joining 2 posteromedian swellings that meet at midline to enclose dorsomedian cephalic depression. Compound eye on subconical tubercle, in lateral view forming ellipse curved around anterior half of tubercle; ommatidia fiat, separated from one another. Occipital lobes short, subquadrate, joined by posterodorsal low transverse ridge. Cephalic sculpturing opaque, coarsely rugose except finely granulose antennal fossae, ocular prominences and most of dorsomedian depression. Scapes transversely rugose, base strongly bent, with rigid decumbent hairs. Antennal fossae relatively large, reniform. Dorsal mandibular surface striate, smooth and shiny along chewing border and distad; chewing border with 8 widely spaced teeth, apical tooth largest. Palpal formula: 3: 1 or 3:2. In situ count. Transverse carina lacking on cervical area; pronotum with median longitudinal carina, laterally with more or less parallel rugulae. Lateral margins of propleura and pronotum evenly curved, without denticle or angle. Mesonotum with 4 denticles, anterior pair longer than posterior; neither promesonotal suture nor metanotal sulcus evident. Anepisternum with low rugae, dorsoposteriorly bound by brief carina; mesopleuron with short ventral carina at mesosomal constriction. Rugae on mesosoma not as broad and coarse as on head; sculpture finer with sparse rugulae. Mesometanotum without well defined longitudinal carinae. Mesosoma laterally with relatively straight anterior pronotal margin; margins of posterior pronotum and mesonotum form convexity interrupted by mesonotal denticles. Metanotum concave; dorsal propodeal face very broadly convex, almost straight, about twice as long as declivitous face. Propodeal dorsum with 2 posterior denticles; base of each propodeal denticle joined to inferior propodeal lobe by vertical carina. Mesopleuron with low anteriorly projecting ventral lobe, just dorsad of mesocoxa. Pronotal-mesopleural suture distinct, terminating dorsally at brief lobe overlapping mesothoracic spiracle; small tubercle present at apparent dorsal end of metapleura. Metapleura and lateral propodeal faces with finely granulose sculpturing, no rugae. Propodeal spiracle prominent, opening directed obliquely laterally. Dorsal propodeal surface forms slightly elevated rectangular surface bordered anterad by transverse carina and laterally by longitudinal carinae that end posterad at propodeal denticles. Convex propodeal lobes present. Petiole slightly pedunculate, node broadly convex, its posterolateral margins angulate and pointing obliquely posterad; low anteroventral lobe present. Petiolar and postpetiolar dorsum rugulose. Postpetiole laterally with convex anterodorsal margin; ventral margin straight, bound at each end by raised triangular margins; dorsal surface with posterolateral ridge ending in rounded lobe. First gastral segment with anterodorsal lobe, a continuous extension of gastral sculpturing partially overlapping constriction of helcium dorsally, apex bluntly pointed and base with modest but well-defined transverse concavity. Posterodorsal margin of postpetiole covers most of lobe. Gaster laterally subglobulose, dorsal margin evenly convex and ventral margin sharply convex; tergum of gastral segment I with rugulae forming almost areolate pattern, sternum with rugulae along posteromedian area, fading out towards base; low lateral longitudinal carinae present on tergum. Procoxae mostly smooth except for low rugulae towards apex, no rugulae on meso- and metacoxae. Apex of metacoxa with a sulcus along each side of insertion of trochanter, each sulcus divided into rounded cells. Body without pubescence except on antennal flagella, protibiae and tarsi. Hairs on mesosoma rigid and frequently capitate, those on gaster slender and subdecumbent; head with sparse depressed hairs; vertex and occiput with erect to suberect rigid hairs. Body brown, mandibular masticatory border black.

Type Material

Holotype. Peru, Madre de Dios, Cuzco Amazonico, 15 km NE Puerto Maldonado, Rio Tambopata, 200 m, 21-VI-89, S.P. Cover, J.E. Tobin, leg. CA-357. Plot IE 24. Worker deposited in Museum of Comparative Zoology. Paratypes. (1) Peru, Madre de Dios, Estacion Pakitza-Manu, 13-17/02/92, R. Combra, D. Quintero leg. Worker deposited in Centro de Pesquisas do Cacau. (2) Colombia, Meta, Parque Natural Nacional La Macarena, IX-90, M.T. Barreto leg. Worker deposited in Museo de Historia Natural. (3) PERU, Madre de Dios, Manu Reserve Zone, Pakitza Station. X-88. J. Tobin leg. Worker deposited in Instituto de Zoologia Agricola.

F. Fernandez has supplied additional data about the locality for the Colombian specimen: “primary forest between Rfos Duda and Guayabero, some kilometres west of the town La Macarena, 350 m.”


The species name is derived from the Greek words for large, mega, and head, kephale. It alludes to the prominent head.


References based on Global Ant Biodiversity Informatics

  • Fernández, F. and S. Sendoya. 2004. Lista de las hormigas neotropicales. Biota Colombiana Volume 5, Number 1.
  • Lattke, J.E. 1999. A new species of fungus-growing ant and its implications for attine phylogeny (Hymenoptera: Formicidae). Systematic Entomology 24:1-6
  • Schultz T. R., J. Sosa-Calvo, S. G. Brady, C. T. Lopes, U. G. Mueller, M. Bacci, and H. L. Vasconcelos. 2015. The most relictual fungus-farming ant species cultivates the most recently evolved and highly domesticated fungal symbiont species. The American Naturalist (in press).
  • Solomon S. E., C. Rabeling, J. Sosa-Calvo, C. Lopes, A. Rodrigues, H. L. Vasconcelos, M. Bacci, U. G. Mueller, and T. R. Schultz. 2019. The molecular phylogenetics of Trachymyrmex Forel ants and their fungal cultivars provide insights into the origin and coevolutionary history of ‘higher-attine’ ant agriculture. Systematic Entomology 44: 939–956.