Pheidole zannia

Pheidole zannia inhabits montane habitats from 1370 to 1740 m elevation, in areas with mesophyll cloud forest and mixed pine, oak, and Liquidambar forests. It prefers open and disturbed areas along roadsides, in coffee farms, and in second growth vegetation. For example, in La Muralla National Park near La Union, intensive Winkler sampling of mature cloud forest did not yield this species, but a nest was discovered (from which the type series was obtained) just outside the park and adjacent to the forest, along a road edge through pasture. This nest was in the soil of the road bank. There was a 2 mm tall turret marking the nest entrance, and the main nest chamber was about 10 cm deep, horizontally into the bank from the entrance. The main chamber contained a single colony queen, minor and major workers, and brood. Other collections have come from baiting or Winkler samples.

Identification
Minor: face smooth and shiny; posterior margin of head in face view rounded laterally, somewhat flattened posteriorly; promesonotal groove absent; dorsal promesonotum and propodeum foveolate; lateral pronotum foveolate with medial smooth, shiny patch; katepisternum mostly smooth and shiny, with or without strip of foveolation posteriorly; propodeal spines short, upturned, about one fourth length of posterior face of propodeum; gaster smooth and shining; erect setae on mesosomal dorsum and gaster; tibiae with a few short, erect setae; bicolored, with sharply contrasting black head and gaster, light orange mesosoma.

Major: head elongate, strongly incised between vertex lobes, posterior face transversely depressed between vertex lobes and anterior portion of head; inner hypostomal teeth present, closely spaced; scape base terete; antennal scrobes distinct, smooth and shiny, delimited dorsally by frontal carinae, ventrally by carinulae, not delimited posteriorly; face longitudinally carinulate, interspaces smooth and shining; propodeal spines upturned, about one fourth to one third length of posterior face of propodeum; gastral dorsum smooth and shining; sides of head with abundant short erect setae; abundant short erect setae on mesosomal dorsum and gaster; tibiae with erect setae; color as in minor worker.

Measurements, minor worker: HW 0.43, HL 0.47, SL 0.42, EL 0.10, WL 0.57, PSL 0.04, PTW 0.08, PPW 0.13, CI 91, SI 98, PSLI 8, PPI 152 (n=11).

Measurements, major worker: HW 0.83, HL 1.00, SL 0.43, EL 0.13, WL 0.84, PSL 0.07, PTW 0.17, PPW 0.30, CI 83, SI 52, PSLI 9, PPI 178 (n=8).

Measurements, queen: HW 0.78, HL 0.81, SL 0.45, EL 0.25, WL 1.35, PSL 0.09, PTW 0.25, PPW 0.45, CI 96, SI 57 (n=1).

Other New World species with similar morphometric profile are Pheidole arboricola, Pheidole crinita, Pheidole gnomus, Pheidole humeralis, Pheidole metallescens, Pheidole mosenopsis, Pheidole neolongiceps, Pheidole pygmaea, Pheidole similigena, Pheidole subarmata, Pheidole triplex, and Pheidole tysoni. Most of these have major workers with the posterior half of the face smooth, lacking longitudinal carinulae, and there is no transverse impression on the face. Pheidole gnomus, from Ecuador, is similar to P. zannia but has transverse carinular on vertex lobes and more normal red brown coloration. Pheidole mosenopsis, from Bolivia and known only from the major, is similar but has less pronounced carinular on vertex lobes, no transverse impression on the face, more normal red brown coloration, and distinctive mandibles with flat dorsal surface and elevated basal margin. Pheidole neolongiceps, from Cuba, is similar but has more uniform longitudinal carinae on face, no transverse face impression, and dark coloration. Pheidole triplex, from Trinidad, has coloration approaching P. zannia. The major worker has a dark head, contrasting orange mesosoma, and red brown gaster. The minor worker is uniform yellow orange. Other than color, P. triplex is very similar to the widespread and common species P. subarmata.

Pheidole zannia is in a group of species related to Pheidole mera (see Comments under Pheidole andersoni). The harlequin color pattern is unique and highly divergent in the group, placing it in a mimicry complex with the unrelated Pheidole balatro (see comments there).

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

Nomenclature

 *  zannia. Pheidole zannia Longino, 2019: 64, fig. 9 (w.q.) HONDURAS.

Type Material

 * HOLOTYPE: 1 major worker, Honduras, Olancho: 9km NNW La Union, 15.09397 -86.75244, ±50 m, 1470 m, 4 May 2010, road edge near cloud forest, nest in soil (J. Longino#6982) [CAS, unique specimen identifier CASENT0615634].
 * PARATYPES: major, minor worker, queen: same data as holotype [CAS, DZUP, JTLC, MCZC, USNM].

Etymology
The zanni were comic servant characters in sixteenth century Italian theater, from which harlequin characters were derived.

References based on Global Ant Biodiversity Informatics

 * Longino J. T. 2019. Pheidole (Hymenoptera, Formicidae) of Middle American wet forest. Zootaxa 4599: 1-126