Pheidole branstetteri

This species occurs in lowland rainforest to cloud forest. It is known most abundantly from baits on the forest floor, and major workers are often found with minor workers at baits. Minor workers are also occasionally collected in Winkler samples of sifted leaf litter. Isolated minor workers from the Sierra Madre de Chiapas, tentatively identified as this species, were also collected in beating samples. (Longino 2009)

Identification
With the general habitus and morphometric profile of Pheidole plebecula. Minor worker: face uniformly foveate versus smooth and shining (plebecula). Major worker: petiolar node in posterior view with dorsal margin distinctly bilobed, medially concave, wider than one half width of postpetiole, versus dorsal margin weakly convex, flat, or weakly concave, about one half width of postpetiole; face with vertex lobes always smooth and shiny versus usually with roughened sculpture extending almost or entirely to posterior margin of vertex, less often vertex lobes smooth and shiny; promesonotum with at most 2 very short setae, variably located, versus promesonotum usually with three pairs of stiff short erect setae, less often with fewer; gastral dorsum always devoid of erect setae versus usually with at least a few stiff erect setae, rarely totally lacking (plebecula). (Longino 2009)

Distribution
This species is most thoroughly known from rainforest areas of northern Chiapas, Mexico. Isolated minor workers from the Sierra Madre de Chiapas are tentatively identified as this species, but there are slight differences in morphology and no major workers have been collected to support the identification.

Distribution based on Regional Taxon Lists
Neotropical Region: Belize, Guatemala, Honduras, Mexico.

Worker
Minor

Nomenclature

 *  branstetteri. Pheidole branstetteri Longino, 2009: 17, fig. 2 (s.w.) MEXICO.

Description
Minor Measurements (paratype): HL 0.66, HW 0.59, HLA 0.24, SL 0.72, EL 0.14, ML 0.81, PSL 0.09, PMG 0.03, SPL 0.03, PTW 0.13, PPW 0.18, CI 90, SI 122, PSLI 13, PMGI 5, SPLI 5, PPI 137.

Measurements (n=14): HL 0.59-0.70, HW 0.56-0.66, SL 0.63-0.78, CI 85-98, SI 102-132.

Mandible smooth and shining; clypeus faintly foveolate, overlain with reticulate rugulae; face uniformly foveolate, occasionally overlain with weak rugulae; margin of vertex uniformly rounded or flattened with median impression; occipital carina narrow, not or barely visible in full face view; scape with sparse erect setae longer than maximum width of scape; promesonotal groove strongly impressed; propodeal spines present; pronotal dorsum foveolate, overlain with reticulate rugulae; side of pronotum foveolate anteriorly and smooth and shiny posteriorly, or entirely foveolate; katepisternum and dorsal and lateral faces of propodeum uniformly foveate with variable presence of overlying rugulae; promesonotal dorsum with about six pairs short stiff erect setae; dorsal (outer) margin of hind tibia with decumbent pubescence and 0-3 suberect setae subequal in length to maximum width of tibia; first gastral tergum smooth and shining or with small area of faint foveolate sculpture near postpetiolar insertion; gastral dorsum with sparse stiff erect setae; color orange.

Major Measurements (holotype): HL 1.01, HW 1.05, HLA 0.34, SL 0.72, EL 0.19, ML 1.01, PSL 0.09, PMG 0.05, SPL 0.05, PTW 0.26, PPW 0.35, IHT 0.36, OHT 0.43, CI 104, SI 68, PSLI 9, PMGI 5, SPLI 4, PPI 131, HTI 84.

Measurements (n=7): HL 0.92-1.04, HW 0.92-1.17, SL 0.69-0.73, CI 99-113, SI 60-75.

Mandible smooth and shiny; clypeus smooth and flat with pronounced anterior notch; anterior face foveolate overlain with reticulate rugulae, grading to foveolate between frontal carina and compound eye, grading to smooth and shining on vertex lobes, medial area between frontal carinae foveolate overlain with longitudinal carinulae; head with no setae projecting from lateral or posterior margins of head in face view; scape smooth and shining, terete at base, with appressed pubescence and 1-3 suberect setae, these shorter than maximum width of scape; hypostomal margin gently curved; median tooth at most an inconspicuous gibbosity; inner hypostomal teeth thin and pointed, much closer to outer hypostomal teeth than to midline; promesonotal groove strongly impressed; propodeal spines present; pronotal dorsum weakly foveolate rugulose, anterior margin and sides smooth and shining; katepisternum, lateral and dorsal faces of propodeum foveolate; dorsal (outer) margin of hind tibia with short appressed pilosity only, no long erect hairs; mesosomal dorsum devoid of erect setae or with 1-2 very short, irregularly located stiff erect setae; petiolar node in posterior view with dorsal margin distinctly bilobed, medially concave, wider than one half width of postpetiole; in dorsal view postpetiole lenticular but not strongly conulate, smooth and shining or very faintly foveolate; first gastral tergite smooth and shining, completely devoid of erect setae; color orange.

Type Material
Holotype major worker. Mexico, Chiapas: Nahá, 16.96291°N 91.59335°W, ±100m, 985m, 10 Jun 2008 (LLAMA#Ba-A-07-1-01-07) UNAM, unique specimen identifier CASENT0609076.

Paratypes: major and minor workers. Same data as holotype; Mexico, Chiapas: Nahá, 16.94860°N 91.59957°W, ±200m, 950m, 10 Jun 2008 (LLAMA#Ba-A-07-2-02-03 and Ba-A-07-2-02-12); Mexico, Chiapas: Nahá, 16.97978°N 91.58544°W, ±100m, 860m, 12 Jun 2008 (LLAMA#Ba-A-07-3-03-02 and Ba-A-07-3-04-05), , , , , , , , UNAM,.

Etymology
This species is named for Michael Branstetter, a student of myrmecology and an indispensable participant in the LLAMA project.

References based on Global Ant Biodiversity Informatics

 * Dattilo W. et al. 2019. MEXICO ANTS: incidence and abundance along the Nearctic-Neotropical interface. Ecology https://doi.org/10.1002/ecy.2944
 * Longino J. T. 2009. Additions to the taxonomy of New World Pheidole (Hymenoptera: Formicidae). Zootaxa 2181: 1-90.
 * Longino J. T. L., and M. G. Branstetter. 2018. The truncated bell: an enigmatic but pervasive elevational diversity pattern in Middle American ants. Ecography 41: 1-12.
 * Vásquez-Bolaños M. 2011. Lista de especies de hormigas (Hymenoptera: Formicidae) para México. Dugesiana 18: 95-133