Pheidole mooreorum

Longino, J. T., 2009, Additions to the taxonomy of New World Pheidole (Hymenoptera: Formicidae)., Zootaxa 2181, pp. 1-90 : 56-57

Pheidole mooreorum

Pheidole mooreorum Wilson, 2003: 209 , figs. Holotype major worker and associated paratype minor worker: Mexico, Veracruz, Los Tuxtlas, 10km NNW Sontecomapan, 18°35'N 95°05'W, 200m, 20 Mar 1985, ground foragers, rainforest(P. S. Ward 7339) [ MCZ] (examined).

Pheidole fariasana Wilson, 2003: 155 , figs. Holotype major worker and associated paratype minor worker: Mexico, Tamaulipas, 1mi E Gomez Farias, 1400', 23 Dec 1972, deciduous tropical forest, nesting in ground under stone (R. J. Hamton, A. B. Hamton, B. S. Ikeda) [ MCZ] (examined). New synonymy.

Geographic Range

Mexico (Tamaulipas) to Costa Rica (northern Pacific lowlands and northern cordilleras).

Biology

This species occurs in a wide variety of habitats: dry forest, rainforest, and cloud forest, from sea level to 1800m elevation, in disturbed synanthropic habitats or less disturbed forest with intact canopy. It can be locally common. Collections are most often from baits on forest floor, or scattered workers in Winkler samples. Major workers are often recruited to baits along with minor workers. The types of P. fariasana were from a nest found beneath a stone.

Comments

Over the range of the species there is strong intra- and inter-populational variation. Minor workers: the pronotum may be entirely and strongly foveolate (rarely), it may show a patchwork of foveolate sculpture and smooth shiny areas, or it may be completely smooth and shining. Correlated with this is face sculpture, which is usually completely smooth and shining, but in forms with more sculpture on the promesonotum the face may have very faint patches of foveolate sculpture. Major worker: in general the anterior face has longitudinal rugulae with smooth shiny interspaces, and the posterior face is completely smooth and shining. The transition may occur abruptly or gradually, and from just anterior to the level of the compound eyes to somewhat posterior to them. The medial area between the frontal carinae may be completely smooth and shining, or with variable numbers of longitudinal rugulae parallel to and beginning at the frontal carinae and fading medially. The strength and extent of face rugulae correlates with strength of pronotal sculpture on minor workers. The setae projecting from the side of the head in face view vary from long and suberect to short and appressed.

The minor workers of the type series of P. fariasana from Tamaulipas have the intermediate sculptural condition, in which the pronotum is mostly smooth and shining, with a narrow band of foveolate sculpture at the anterior margin and wrapping around onto the ventrolateral margin. The major workers have the face rugulae extending posterior to the compound eyes, and there are abundant suberect setae projecting from the side of the head. In the Sierra Madre de Chiapas, most collections have the intermediate sculptural condition, but the full range of variation occurs. At lower elevations in northern Chiapas, in wet forest areas from 500-1000m, the most common condition is for the pronotum of the minor worker to be almost to entirely smooth and shiny, and the side of the head in the major worker with shorter, more decumbent setae. The type series of P. mooreorum , from Veracruz, matches this lowland form, with the setae on the side of the head even more reduced than on the lowland Chiapas material.

One minor worker from a 500m site in northern Chiapas (Metzabok) and one minor worker from a lowland site in the Lacandon rainforest of northern Chiapas (Playon de la Gloria) have a faint purple sheen, like P. purpurea . Unlike P. purpurea , the pronotum is smooth and shining. These collections do not have associated majors, and given the similarity of minor workers of P. mooreorum and P. purpurea , these may be variants of P. purpurea instead of P. mooreorum .

Sparse minor worker collections from montane sites in Guatemala, and multiple collections with major workers from lowland dry forest habitat in northwestern Costa Rica are, on average, like the type series of P fariasana . Occasionally the sculpture is more extensive. In some lighting conditions the Costa Rican material may have a very faint purple sheen.

In the Cordillera de Tilaran in Costa Rica, in moist forest around 1400m elevation, a relatively uniform population occurs in which the minor workers have a strongly sculptured pronotum, and the minor workers are somewhat bicolored, with mesosoma light brown and head and gaster darker brown.

In Chiapas, Mexico, P. mooreorum is broadly sympatric with P. purpurea , with the former being more abundant in middle to high elevations and the latter relatively more abundant in the lowlands. The minor workers are indistinguishable in the Sierra Madre de Chiapas, where both have an intermediate sculptural condition on the minor worker pronotum and neither have the purple sheen. In the Chiapas lowlands they are more differentiated, with P. mooreorum having a smooth pronotum and no purple sheen, and P. purpurea having a sculptured pronotum and often a purple sheen.

Given the high degree of morphological variability, it is likely that P. mooreorum will resolve into multiple cryptic species.