Trachymyrmex nogalensis

Trachymyrmex nogalensis
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hymenoptera
Family:	Formicidae
Subfamily:	Myrmicinae
Tribe:	Attini
Genus:	Trachymyrmex
Species:	T. nogalensis
Binomial name
	Trachymyrmex nogalensis; Byars, 1951 Specimen labels

Trachymyrmex nogalensis is rarely collected and is also the only Trachymyrmex species in the US whose male remains undiscovered.

Identification

Trachymyrmex nogalensis is distinguished from other US Trachymyrmex species by the short, unique “scrobes” and the unusual basal lobe on the antennal scapes. In the field it can be confused only with the occasionally sympatric Trachymyrmex arizonensis, from which it is easily distinguished by the basal lobe on the antennal scape, (absent in T. arizonensis), and the distinctive frontal lobes of T. arizonensis, (absent in T. nogalensis). (Rabeling et al. 2007)

Keys including this Species

Key to US Trachymyrmex

Distribution

Only known from two locations in Arizona: the type locality, Nogales (in Santa Cruz County) and the Chiricahua Mountains (Cochise County) in the southeast corner of the state (Rabeling et al. 2007).

Latitudinal Distribution Pattern

Latitudinal Range: 32.12824° to 31.340378°.


North Temperate	North Subtropical	Tropical	South Subtropical	South Temperate

Source: AntMaps

Distribution based on Regional Taxon Lists

Nearctic Region: United States (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. ‎

From Rabeling et al. (2007): All collections have been made in mid elevation habitats at 1200–1550 m. Byars (1951) collected workers and dealate queens on the porch of his house. Unfortunately, he provided no further information on the surrounding habitat or on any other nests. In the Chiricahua Mountains, we found T. nogalensis in creosote bush, mesquite-dominated desert habitats and on a rocky limestone outcrop dominated by Ocotillo, Acacia, Agave and Mimosa. Nests were cryptic and the entrances were located in cracks on rock-face. No information is available on nest architecture, fungus gardens, or number of workers in a colony because the extremely rocky ground makes excavation close to impossible. Trachymyrmex nogalensis is seldom encountered, probably because of it nocturnal foraging behavior and its cryptic nest sites. Studies of ecology, behavior and fungus cultivation would be fruitful areas for further research.

Castes

Images from AntWeb


Paratype of Trachymyrmex nogalensis. Worker. Specimen code casent0103490. Photographer April Nobile, uploaded by California Academy of Sciences.	Owned by USNM, Washington, DC, USA.

Nomenclature

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

nogalensis. Trachymyrmex nogalensis Byars, 1951: 109, figs. 1, 2 (w.) U.S.A. (Arizona).
- Type-material: holotype worker, paratype workers (number not stated, “numerous”), 2 paratype queens.
- Type-locality: holotype U.S.A.: Arizona, Nogales, 1.x.1946 (L.F. Byars); paratypes: workers with same data, 1 queen with same data but 10.vii.1947, 1 queen with same data but 5.viii.1948.
- Type-depositories: USNM (holotype); AMNH, MCZC, USNM (paratypes).
- Rabeling, et al. 2007: 13 (q.).
- Combination in Trachymyrmex: Solomon, Rabeling, et al. 2019: 948.
- Status as species: Smith, M.R. 1958c: 137; Hunt & Snelling, 1975: 22; Smith, D.R. 1979: 1411; Bolton, 1995b: 421; Rabeling, et al. 2007: 13 (redescription); Sánchez-Peña, et al. 2017: 87 (in key).
- Distribution: U.S.A.

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

Description

Worker

Diagnosis from Rabeling et al. (2007): HL 1.1–1.35, HW 1.05–1.5, CI 96–112, SL 1.4–1.8, SI 117–133, ML 1.7–2.2. Large species (HL 1.1–1.35; HW 1.05–1.5), with relatively long legs and antennae (SI 117–133). Head generally longer than broad (CI 96–112), tapering slightly anterior to the eye, posterior border weakly concave. Antennal scape narrowing abruptly toward the antennal insertion, with a conspicuous lobe just distal to the narrowing. Frontal lobes well developed, evenly rounded, equilateral. Frontal carinae short, joining with preocular carinae to form short, distinctive “scrobes” that end just posterior to the level of the eye. Anterior terminus of the preocular carina forming a small tooth in full-face view. Anterolateral promesonotal teeth spinelike, sharply pointed, directed upwards and forward in side view. Propodeal spines toothlike, shorter than the distance between their bases. Body moderately tuberculate. Color yellowish brown.

Queen

Diagnosis from Rabeling et al. (2007): HL 1.36–1.45, HW 1.4–1.45, CI 97–104, SL 1.64–1.8, SI 117–124, ML 2.25–2.4. Generally as in worker diagnosis, but mesosoma with caste-specific morphology relating to wing-bearing and the head bearing small ocelli. Dorsolateral pronotal teeth large, tuberculate and sharply pointed in dorsal view; ventrolateral pronotal teeth well-developed, resembling a blunt lobe. Mesoscutum lacking longitudinal rugulae but with numerous small tubercles, each bearing a short, sharply recurved seta.

Male

Males are not known for this species.

Type Material

Holotype worker National Museum of Natural History. Examined (Rabeling et al. 2007).

Type Locality Information

Nogales, Arizona, U.S.A. (Rabeling et al. 2007).

Etymology

Trachymyrmex nogalensis was described from Nogales, Arizona, based on workers that Byars collected from a colony nesting under his house. The species name clearly refers to the type locality. (Rabeling et al. 2007)

References

Byars, L. F. 1951. A new fungus-growing ant from Arizona. Proc. Entomol. Soc. Wash. 53: 109-111 (page 109, figs. 1, 2 worker described)
Rabeling, C., S. P. Cover, R. A. Johnson, and U. G. Mueller. 2007. A review of the North American species of the fungus-gardening ant genus Trachymyrmex (Hymenoptera : Formicidae). Zootaxa.1-53.
Solomon, S.E., Rabeling, C., Sosa-Calvo, J., Lopes, C.T., Rodrigues, A., Vasconcelos, H.L., Bacci Jr, M., Mueller, U.G., Schultz, T.R. 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 (doi:10.1111/syen.12370).

References based on Global Ant Biodiversity Informatics

Cover S. P., and R. A. Johnson. 20011. Checklist of Arizona Ants. Downloaded on January 7th at http://www.asu.edu/clas/sirgtools/AZants-2011%20updatev2.pdf
Johnson R. Personnal Database. Accessed on February 5th 2014 at http://www.asu.edu/clas/sirgtools/resources.htm
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
Rabeling C., S. P. Cover, R. A. Johnson, and U. G. Mueller. 2007. A review of the North American species of the fungus-gardening ant genus Trachymyrmex (Hymenoptera: Formicidae). Zootaxa 1664: 1-53
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.