Mycetagroicus urbanus

Mycetagroicus urbanus
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hymenoptera
Family:	Formicidae
Subfamily:	Myrmicinae
Tribe:	Attini
Genus:	Mycetagroicus
Species:	M. urbanus
Binomial name
	Mycetagroicus urbanus; Brandão & Mayhé-Nunes, 2001 Specimen Labels

Brandao and Mayhe-Nunes (2001) - In Cincinnato R. Goncalves notebook we have found the following information: “# 482 - Mycetosoritis. Attini em revoada [in dispersion night]. Ibirapuera, Sao Paulo, SP, 10.x.1943. C. R. Goncalves.” He recorded the nest entrance as narrow and surrounded by a single low mound, made up of fine grains of earth. The fact that Goncalves collected these specimens while in dispersion flight suggests that he may have collected sexuals along with the workers we have found in the MZSP. Supporting this idea, we have found in Kempfs notes, records on males of an “unidentified attine genus,” supposedly belonging to this sample. However, all attempts made to locate sexuals of this sample failed. Sexuals from this locality with the same label number were not found at CELC, where most of Goncalves material has been deposited.

Identification

Unlike Mycetagroicus cerradensis and Mycetagroicus triangularis, M. urbanus does not have lateral clypeal teeth; M. urbanus share with M. triangularis the presence of two conspicuous median low irregular spines in the middle of the pronotum. Only the funicular segments I and VIII-X are longer than broad, as in M. triangularis, but the mesonotal protuberance is higher than in the other species. The M. urbanus frontal lobes are rounded, with their largest width posterior to the antennal insertions One paratype worker is a relatively aged worker, considering the material already accumulated over the integument: its mandibular teeth apices are very much worn out, suggesting that younger workers of M. urbanus may have much more acute and long mandibular teeth. (Brandao and Mayhe-Nunes 2001)

Keys including this Species

Key to Mycetagroicus

Distribution

Latitudinal Distribution Pattern

Latitudinal Range: -23.53333333° to -23.53333333°.


North Temperate	North Subtropical	Tropical	South Subtropical	South Temperate

Source: AntMaps

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

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.

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.

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. ‎

Castes

Worker


.

Nomenclature

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

urbanus. Mycetagroicus urbanus Brandão & Mayhé-Nunes, 2001: 657, figs. 17-23 (w.) BRAZIL.

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

Description

Worker

Brandão and Mayhé-Nunes. 2001. Figure 20.

Brandão and Mayhé-Nunes. 2001. Figure 19.

Brandão and Mayhé-Nunes. 2001. Figure 22.

Brandão and Mayhé-Nunes. 2001. Figure 23.

TL 2.64; HL 0.91; HW 0.82; IFW 0.43; ScL 0.71; TrL 1.11; HfL 0.88. Color medium brown, gaster and frons darker. Short and scarce hairs all over the body, denser on appendages.

Head. Dorsal surface of the mandibles not so strongly sculptured as in the other species (some 20 rugulae in a straight line perpendicular to the mandible, at midlength), fading but not ending in a straight line as in M. cerradensis, each rugula blending with the superficial texture of the mandibles near the smooth flange at the masticatory margin. Masticatory margin of the mandible with an apical tooth and 6 sub-apical irregular teeth, the 3 apical ones rounded and more spaced, while the 3 basal ones are more prominent and closer to each other: outer border straight from the apical tooth level of the second basal tooth. Clypeus lateral regions near the base of frontal lobes without projections. Frontal area inconspicuous. Frontal lobes rounded, their largest width posterior to the antennal insertions. Frontal carinae slightly sinuous, fading well before reaching the occiput. Eyes with 10 facets across the greatest diameter. Antennal scapes surpassing the occipital margin by 1/6 of its chord length when laid back over the head as much as possible. Only funicular segments I and VIII-X longer than broad, the other subequal to each other.

Alitrunk. Lateral pronotal spines scarcely projecting from pronotal lateral margin, irregular in shape; pronotum with a pair of short but conspicuous median spines; antero-inferior corners angulated, Mesonotum with a median projection as a relatively high conical protuberance. microscopically tuberculated. Metanotal groove relatively narrow and deeply impressed. Opening of propodeal spiracle almost rounded in side view.

Petiole, postpetiole and gaster. Dorsum of petiole with two low longitudinal ridges; in lateral view, triangular and acute; the node proper, as seem from above, slightly broader than long. Postpetiole slightly longer than broad in dorsal view; the posterior margin projected above the level of the postpetiole dorsum, in lateral view. Gaster hair pits as irregularly distributed as in M. triangularis, without dorsal keels.

Type Material

Holotype: Worker BRAZIL, Sao Paulo State: Sao Paulo (23° 32' S, 46° 37' W). (Parque do) Ibirapuera, 10.x.1943, C. R. Goncalves leg. (# 482 on Goncalves’s notebook), deposited at Museu de Zoologia da Universidade de Sao Paulo. Paratypes: 6 workers, same data as halo type (3 MZSP- one prepared for SEM: 1 Instituto de Biologia Universidade Federal Rural do Rio de Janeiro, 1 National Museum of Natural History, 1 The Natural History Museum).

Etymology

We have chosen the Latin name urbanus because the only known sample of this species was collected at the main public park within Sao Paulo city.

References

References based on Global Ant Biodiversity Informatics

Brandão C. R. F., and A. J. Mayhé-Nunes. 2001. A new fungus-growing ant genus, Mycetoagroicus gen. n., with the description of three new species and comments on the monophyly of the Attini (Hymenoptera: Formicidae). Sociobiology 38: 639-665.
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