Mycetomoellerius mesopleuralis

Mycetomoellerius mesopleuralis
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hymenoptera
Family:	Formicidae
Subfamily:	Myrmicinae
Tribe:	Attini
Genus:	Mycetomoellerius
Species:	M. mesopleuralis
Binomial name
Mycetomoellerius mesopleuralis Santos, Chaul & Serrão, 2025

Photo Gallery

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  Santos et al. (2025), Fig. 8. Mycetomoellerius mesopleuralis holotype (MZSPHYM0136545). A, full-face view; B, mesosoma, petiole and postpetiole in profile view; C, profile view; D, dorsal view. Red arrowhead, prolonged digitiform protuberance in the inferior region of lower mesopleuron. Scale bars 0.2 mm (A), 0.5 mm (B), and 1 mm (C and D).

Identification

Body pilosity sparse, setae long and curved. Lateral pronotal spines well-developed; median pronotal spines well-developed, slightly basally fused. Mesonotum with two pairs of protuberances, anterior pair larger than posterior; mesopleural surface, apart from microtubercles, with one distinct digitiform protuberance anteroventrally directed. Frontal lobes subcircular, with crenulate margins; frontal carinae reach the vertexal margin. Postocular protuberance well-developed; preocular carinae extending to the vertexal margin. Vertexal corners angled, vertexal margin with distinct median emargination. Mandibles basally with oblique striations. First gastral tergite with linked tubercles, and a pair of lateral ridges.

Mycetomoellerius mesopleuralis is distinguishable from the others in the genus by the lower mesopleuron projection, which, in other species such as Mycetomoellerius janildae, is limited to just a small edge of the cuticle, or located on the upper mesopleuron (as in Mycetomoellerius holmgreni). Mycetomoellerius mesopleuralis shows some resemblance to Mycetomoellerius relictus and M. janildae for sharing with them the well-developed lateral pronotal spines. Short tubercles, a common feature of the genus, are much more developed and evident in M. mesopleuralis than in most other species, particularly on the antennal scapes and the first gastral tergite.

Santos et al. (2025) provide a multi-entry interactive key based on the xper3 platform which contains 27 characters and, as terminals, 30 species of Mycetomoellerius, representing almost all described species except for Mycetomoellerius echinus, Mycetomoellerius gaigei and Mycetomoellerius guianensis, which are excluded due to lack of clear information or available specimens for study.

Distribution

This species is only known from three localities in the Atlantic forest domain, São Paulo, Brazil.

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  Santos et al. (2025), Fig. 10. Distribution maps of Mycetomoellerius janildae, M. mesopleuralis and M. relictus in South America.

Latitudinal Distribution Pattern

Latitudinal Range: -20.8° to -22.2°.

North Temperate	North Subtropical	Tropical	South Subtropical	South Temperate

• Source: Santos et al., 2025

Distribution based on Regional Taxon Lists

Neotropical Region: Brazil (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.

Biology

Expand 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. some Crematogaster some Lasius 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. some Apterostigma Cyatta (1 species) some Cyphomyrmex Kalathomyrmex (1 species) Mycocepurus (6 species) Myrmicocrypta (31 species) Mycetarotes (4 species) Mycetosoritis (2 species) Mycetophylax (21 species) Paramycetophylax (1 species) Xerolitor (1 species) Coral Fungus Agriculture Practiced by species in the Apterostigma pilosum species-group, which cultivate fungi within the Pterulaceae. some Apterostigma 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. some Cyphomyrmex 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. Mycetomoellerius (33 species) Paratrachymyrmex (9 species) Sericomyrmex (11 species) Trachymyrmex (9 species) 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. Acromyrmex (51 species) Amoimyrmex (3 species) Atta (20 species) 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. ‎

Nomenclature

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

• mesopleuralis. Mycetomoellerius mesopleuralis Santos, Chaul & Serrão, 2025: 105, fig. 8 (w.) BRAZIL (São Paulo).

Type Material

• Holotype worker: BRA: SP, Agudos, -20.758332, -42.864533, 1959-04-30, Kempf, W. (1 worker, MZSPHYM0136545) [MZUSP].
• Paratypes workers: BRA: SP, Agudos, -20.758332, -42.864533, 1959-04-30, Kempf, W. (Twelve workers with the following codes: MZSPHYM0144990, MZSPHYM0144991, MZSPHYM0136543, MZSPHYM0136544, MZSPHYM0144992, MZSPHYM0144993, MZSPHYM0136545, MZSPHYM0144994, MZSPHYM0144995, MZSPHYM0136546, MZSPHYM0144996, and MZSPHYM0144997) [all in MZUSP, except MZSPHYM0144991 which is in DZUP]. BRA: SP, Luiz Antônio, Estação Ecológica Jataí, -21.573941, -47.734546, Rogerio & Adriana col. (1 worker, MZSPHYM0136547) [CELC]. BRA: SP, Mogi Guaçu, Fazenda Caipirinha, -22.226970, -47.091813, Leal, I. R. (Two workers with the following codes: MZSPHYM0136548 and MZSPHYM0144998) [MZUSP].

References

• Santos, C.D.A.D., Chaul, J.C.M., Serrao, J.E. 2025. Taxonomic contributions to Mycetomoellerius Solomon et al., 2019 (Hymenoptera: Formicidae: Myrmicinae): description of two new species and a key for the genus. Zootaxa 5569(1), 93–118 (doi:10.11646/zootaxa.5569.1.3).