Tetramorium azcatltontlium

Marques et al. (2011) - Specimens were collected in a tropical dry forest remnant on the Pacific coast of Jalisco state, Mexico, into the region of Chamela. The landscape consists of low hills (50–180 m elevation) with steep convex slopes dominated by tropical dry forest. The climate is highly seasonal with a pronounced dry season. Individual workers were sampled by epigaeic pitfall traps baited with sardine and honey.

Identification
Marques et al. (2011) - A member of the T. tortusum species group. The species of this tortuosum group are primarily distributed in rainforests and temperate forests of high altitude from Mexico and U.S. (Bolton 1979; Vásquez-Bolaños 2007). T. azcatltontlium is the first known from tropical dry forest.

T. azcatltontlium is smaller than any other species of the tortosum group from America. Tetramorium placidum have HW 0.66-0.72 mm and TL 3.4 mm, T. azcatltontlium has HW 0.58-0.68 mm and TL 2.8 mm. Unlike T. placidum, the new species have short, triangular and standing propodeal spines; rugolose dorsal surface of the petiole; and sparse pilosity in dorsal surface of alitrunk.

Distribution
Jalisco, Mexico.

Distribution based on Regional Taxon Lists
Neotropical Region: Mexico.

Castes
Known only from the worker caste.

Nomenclature

 *  azcatltontlium. Tetramorium azcatltontlium Marques, et al. 2011: 118, figs. 1, 2 (w.) MEXICO.

Worker
Holotype (mm): TL 2.74, HL 0.70, HW 0.64, CI 91.4, SL 0.56, SI 87.5, PW 0.52, WL 0.84. Paratypes: TL 2.4-2.8, HL 0.62-0.76, HW 0.58-0.68, CI 82.9-97.1, SL 0.48-0.56, SI 82.4-93.3, PW 0.42-0.50, WL 0.76-0.80, (15 measured).

Mandibles triangular with longitudinal fine striations and 7 teeth on the masticatory border. Frontal carina extending beyond posterior margin of eye. The eyes are smaller than 25% of head length, diameter of 0.12 mm. The propodeal spines short, triangular, not reaching the node of the petiole. Head in dorsal view, longitudinal striate; mesosoma and petiole finely reticulated; postpetiole without ornamentation; first gastral tergite without punctuation. In dorsal view, the pilosity of the body is sparse, short, thin and standing, the same diameter of eyes. The pilosity of scape and tibiae is shorter than diameter of the respective appendage. head, mesosoma, petiole, postpetiole and gaster uniform reddish-brown.

Type Material
Holotype worker, Mexico: Jalisco, La Huerta municipally, Cuixmala farm, epigaeic pitfall trap, 19°24’297”N 104°58’968”W, TDF, 180 m of altitude, 18 October 2009, Marques, T. col., deposited in Paratypes: 15 workers, Mexico: Jalisco, La Huerta municipally, Cuixmala farm, epigaeic pitfall trap, 19°24’297”N 104°58’968”W, TDF, 180 m of altitude, 18 October 2009, Marques, T. col., deposited in  (1), CZUG (7),  (1),  (1),  (1),  (1),  (1),  (1),  (1).

Etymology
The specific name is a junction from Nahuatl words “azcatl,” meaning ant, and “tontli,” small. This name alludes to the trait that most differentiates this species from any other Tetramorium tortuosum group. Nahuatl is the language spoken in Central Mexico since at least the seventh century C.E and was the language of the Aztecs.

References based on Global Ant Biodiversity Informatics

 * Castano-Meneses, G., M. Vasquez-Bolanos, J. L. Navarrete-Heredia, G. A. Quiroz-Rocha, and I. Alcala-Martinez. 2015. Avances de Formicidae de Mexico. Universidad Nacional Autonoma de Mexico.
 * Dattilo W. et al. 2019. MEXICO ANTS: incidence and abundance along the Nearctic-Neotropical interface. Ecology https://doi.org/10.1002/ecy.2944
 * Vásquez-Bolaños M. 2011. Lista de especies de hormigas (Hymenoptera: Formicidae) para México. Dugesiana 18: 95-133