Mycetomoellerius ixyodus

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Mycetomoellerius ixyodus
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Mycetomoellerius
Species: M. ixyodus
Binomial name
Mycetomoellerius ixyodus
(Mayhé-Nunes & Brandão, 2007)

A fungus growing ant.

Identification

A member of the Jamaicensis species group. Mayhé-Nunes & Brandão (2007) - This species is easily recognized by the large plate-like triangular tooth projecting from the upper corner of the sharply marginate anterior border of the katepisternum, pronotal spines much longer than mesonotal projections, mid-pronotal projections absent, and by the lack of a well-formed supraocular tumulus.

Keys including this Species

Distribution

Latitudinal Distribution Pattern

Latitudinal Range: 4.088888889° to -10.06666667°.

 
North
Temperate
North
Subtropical
Tropical South
Subtropical
South
Temperate

Distribution based on Regional Taxon Lists

Neotropical Region: Brazil (type locality), Suriname.

Distribution based on AntMaps

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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.
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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.
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Biology

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. ‎

Castes

Known only from the worker caste.

Nomenclature

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

  • ixyodus. Trachymyrmex ixyodus Mayhé-Nunes & Brandão, 2007: 11, figs. 15-18, 30 (w.) BRAZIL.
    • Combination in Mycetomoellerius: Solomon et al., 2019: 948.

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

Mayhé-Nunes & Brandão (2007) - Brazilian specimens from the vicinity of Manaus are slightly larger than other specimens, and lack the reddish hues in the integument; a Suriname series has infuscated antennal scrobes; the vertical furrow, disc of mesonotal shield, longitudinal furrows and sides of tergum I of gaster are masked by an overlying film of a material which renders the integument uniform in color (Pseudonocardia bacteria ? see Currie et al., 1999). These specimens have also the tubercles in front of antennal socket on the median apron of clypeus much larger, upright, almost spine-like; the dorsal disc of pronotum lacks the median pair of teeth, and the mesonotal armature is also likewise low, appearing in dorsal view as depressed spines, the anterior pair pointing laterad, and the posterior pair pointing backwards. Finally, the dorsal armature of the petiolar node consists of two pairs of simple denticles widely separated from each other. Still, they belong to the same species, as shown by the strong tooth on katepisternum, and the main distinguishing characters of this species.

Description

Worker

(n = 8). TL 4.8 (4.4–5.1); DHL 1.47 (1.38–1.54); HW 1.32 (1.25–1.43); IFW 0.86 (0.78–0.88); ScL 1.03 (0.97–1.09); HWL 0.78 (0.65–0.88); MeL 1.85 (1.74–1.97); PL 0.42 (0.38–0.46); PPL 0.44 (0.40–0.46); GL 1.29 (1.20–1.38); HfL 1.91 (1.83–1.95).

Trachymyrmex isthmicus worker. Mayhe-Nunes and Brandao 2007. Figs. 15-18

Light ferruginous; mandibles and tarsi darker. Integument finely and indistinctly shagreened, opaque. Pilosity: short bristly hairs recurved or hook-shaped; all hairs shorter than maximum depth of fore femora except hairs on clypeus which are longer and straight; gastric tergum with both longer curved and shorter hook-like hairs; tarsi with straight and subdecumbent hairs. Pubescence confined to the tips of antennal scapes, funiculi, sides and flexor face of tibiae, and all tarsomeres. Head in full face view (Fig. 15), a little longer than broad (DCI average 90; 88–94). Outer border of mandible feebly sinuous; masticatory margin with two apical and uniform smaller seven teeth. Clypeus median apron with a tubercle near the frontal lobe base. Frontal area deeply impressed. Frontal lobe semicircular, moderately expanded (FLI average 65; 62–67), with free border crenulate, and anteriorly notched between its insertion and a prominent antero-lateral tooth. Frontal carinae moderately diverging caudad, reaching the antennal scrobe posterior end in a small tooth at the posterior margin of head; preocular carina fading out halfway between posterior orbit of eye and tip of antennal scrobe, posteriorly ending in the posterior margin of head as one tubercle, larger than the frontal carinae projections. Supraocular tumulus blunt, microscopically spinous, the head gradually constricted behind the supraocular tumulus, in full-face view. Posterior margin of head flanked by a series of tubercles, continuing forwards to vertex, where it bifurcates and each branch reaches the frontal carinae at the level of the superior eyes orbit. Inferior corner of occiput, in side view, bluntly dentate. Eye faintly surpassing the lateral border of head, with about 13 facets across the greatest diameter. Antennal scape not conspicuously projecting beyond the scrobe when fully lodged, gradually thickened towards apex, its dorsal and anterior face rough by virtue of the minute piligerous tubercles covering.

Mesosoma (Figs. 16, 17). Pronotum dorsum laterally marginate but without distinct transverse carina on the anterior border; inferior margin weakly crenulate; antero-inferior corner with an often apically rounded tooth; paired median teeth absent or represented by a pair of minute widely spaced denticles, which do not differ from other sparse denticles on the pronotum surface; lateral spines much longer than mesonotal projections. Mesonotum with the first and second pair of spines represented by low, multidentate tumescences or ridges that circumscribe a more or less flattened to slightly excavate mesonotal shield; third pair as minute tubercles. Anterior border of katepisternum sharply marginate, with a strong and flattened triangular tooth at its upper third. Metanotal constriction deeply impressed in profile. Basal face of propodeum with a bi or tridentate longitudinal ridge on each side, followed by one to several isolated denticles in front of the bases of the short propodeal spines, which usually bear a subapical accessory tooth; propodeal spines shorter than the distance between their inner bases. Hind femora a little longer than mesosoma length.

Waist and gaster (Figs. 16–18). Dorsum of petiolar node with a bigger anterior pair of teeth or two rows of simple teeth pairs; sternum with a sharp sagital keel; the sides smoothly convex in dorsal view, with minute piligerous tubercles. Postpetiole broader than long, dorsally flat, its posterior border distinctly concave. Gaster, seem from above, subtrapezoidal, little broader behind than in front. Tergum I with the shallowly excavate lateral faces separated from the dorsal surface by strong denticulate longitudinal keels, which fade before reaching the posterior end of the tergite. Between these lateral keels there is another pair of medial longitudinal keels, which divide the dorsum into three longitudinal shallowly excavate furrows, the lateral ones bear piligerous tubercles. Sternum I with a vestigial sagital keel anteriorly.

Type Material

Holotype worker: BRAZIL: Amazonas: Ponta Negra, N. of Manaus, 3.ix.1962, W. L. Brown leg. (deposited in Museu de Zoologia da Universidade de Sao Paulo).

Paratype workers: same data as holotype, 1 worker (deposited in MZSP), Manaus, Br 174, Km 44, EEST S2, 25.ix.1991, A. Harada and A.G. Bandeira leg. 2 workers (deposited in Instituto Nacional de Pesquisas da Amazonia); same locality, campus Fund. Univ. Amaz., 1.x.1987, Brandão and Cancello leg. 1 worker (deposited in MZSP); same locality, BR 174, 2F3, Km 41, Res. 1501 PDBFP, 4.ix.1991, G.A.R. Mello leg. 3 workers (2 deposited in Instituto de Biologia Universidade Federal Rural do Rio de Janeiro, 1 in INPA); same locality, # 4832-RS1301, 16.xii.1993, A.B. Casimiro col., 1 worker (deposited in Centro de Pesquisas do Cacau).

Etymology

We found the Latinized greek name ixyodus in Kempf´s notes for the samples we describe here, ιξψσ, meaning “side,” and οδδ, “triangle,” in reference to the triangular spine on the anterior margin of the katepisternum.

References

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. Orivel, A. Dejean, J. Martin, M. Etienne, B. Corbara, and J. H. C. Delabie. 2009. Baseline study of the leaf-litter ant fauna in a French Guianese forest. Insect Conservation and Diversity 2: 183-193.
  • Mayhe-Nunes A. J., and C. R. F. Brandao. 2007. Revisionary studies on the attine ant genus Trachymyrmex Forel. Part 3: The Jamaicensis group (Hymenoptera: Formicidae). Zootaxa 1444: 1-21.