Tetramorium notomelanum

The specimens were collected in an area with sparse vegetation and low floral diversity. Solitary foraging ants were observed in search of seeds and waste plant tissues of leguminous plants (Prosopis laevigata, Cercidium praecox and Mimosa luisana), which represent an important resource in this area and especially during the dry season. The collection area also has been subject to anthropogenic and natural disturbance, suggesting that this is an early colonizer species because it was not found in undisturbed areas within the Botanical Garden. (Vásquez-Bolaños et al. 2011)

Identification
Vásquez-Bolaños et al. (2011) - A member of the tortuosum-group. In common with described species, the antennae have 11 segments, the petiole is sculptured and nodiform, the propodeum is armed with spines, the mandibles are striate and the gaster unsculptured (Bolton 1977). This species is easily recognized from others of the genus Tetramorium by its coloration pattern. Tetramorium bicolorum is bicolored: dark brown on head while gaster is lighter brownish on alitrunk, petiole and postpetiole; the remaining species of the group (Tetramorium hispidum, Tetramorium mexicanum, Tetramorium placidum and Tetramorium spinosum) show pale to dark brown homogeneous coloration all over the body, while T. notomelanum is completely dark black. Also, T. notomelanum is smaller than T. hispidum, T. mexicanum and T. spinosum, but larger than T. bicolorum and T. placidum. The length of the hairs of the head and pronotum is equal or smaller to the maximal diameter of the eye, a character shared with T. bicolorum and T. spinosum. Other diagnostic characters of T. notomelanum are the reticulated body sculpture and the acuminate propodeal spines relatively longer than that of the other species of the group.

Distribution
Known from the type locality, Zapotitlan Salinas, Puebla, México.

Distribution based on Regional Taxon Lists
Neotropical Region: Mexico.

Biology
Vásquez-Bolaños et al. (2011) - The specimens were obtained from a sampling with a series of pitfall traps (Guzman-Mendoza et al 2010) in “Helia Bravo” Botanical Garden, in the Zapotitlan Salinas area at the southwestern border of the Tehuacan Valley (18°11’- 18º25’ N, 97°39’- 97º22’ W), in Puebla State, Mexico. The elevation range in the Valley varies between 1280 m and 2720 m. The climate of the region is semiarid, with two periods of rain (May to June, and September). Average annual precipitation is 400 mm and mean annual temperature ranges from 18°C to 22°C. The dominant vegetation is represented by xerophytic shrub (Rzedowski 1978).

Castes
Known only from the worker caste.

Nomenclature

 *  notomelanum. Tetramorium notomelanum Vásquez-Bolaños, et al. 2011: 453, fig. 1a-c (w.) MEXICO.

Worker
data for holotype in parenthesis: TL 3.8-4.0 (3.9), HL 0.94-0.98 (0.98), HW 0.84-0.88 (0.88), CI 88.7-91.6 (89.7), SL 0.80 (0.80), SI 81.6-85.1 (81.6), PNW 0.70-0.74 (0.72), AL 1.20-1.26 (1.20).

Antenna with 11 segments. Mandibles showing longitudinal ridges and seven well defined teeth. Frontal carinae extending beyond the upper level of the eyes. Small eyes, about 0.22 mm long. Propodeal spines relatively long and sharp. Dorsal surface of alitrunk and petiole with reticulate sculpturing. Head and postpetiole with longitudinal ridges. Dorsal pilosity of body straight, length similar to diameter of eyes. Hairs of the tibiae and scape longer than the diameter of the corresponding appendage. Head, alitrunk, petiole, postpetiole, gaster and appendages black.

Type Material
Holotype, worker, labeled with the following data, 17 – 21.XII.2003, pitfall tramp 5, sitio El Llano, Jardin Botanico Helia Bravo, Zapotitlan Salinas, Tehuacan, Puebla. Paratypes: three workers, labels with as follow: 17-21.XII.2003, pitfall tramp 5, sitio El Llano, Jardin Botanico Helia Bravo, Zapotitlan Salinas, Tehuacan, Puebla; one worker: VIII 2003, pitfall 5, sitio El Llano, Jardin Botanico Helia Bravo, Zapotitlan Salinas, Tehuacan, Puebla. Holotype and two paratypes deposited at (Entomological Collection of the Centro de Estudios en Zoologia, Universidad de Guadalajara); one paratype deposited in the Ant Collection of the Laboratorio de Ecologia y Sistematica de Microartropodos (LESM), Facultad de Ciencias, Universidad Nacional Autonoma de Mexico, and one paratype deposited in the Collection of William and Emma Mackay Collection, University of Texas, El Paso, Texas.

Etymology
This species is named by the color of the body according with the Greek roots notos that means back, and melas that means black.