Taxonomic History (provided by Barry Bolton, 2016)
Distribution:Neotropical Region: Belize
, Costa Rica
Southern Mexico to Costa Rica. The northern and southern limits of the range should be considered dotted lines at this point, given my lack of knowledge beyond those areas. Elevational range is typically sea-level to about 1600m, where it may be replaced by highland species. An exception may be Biotopo El Quetzal in Guatemala, where a harrisonfordi
-like form extends to nearly 2000m.
This species is a ubquitous inhabitant of wet forest leaf litter. It is one of the most frequently encountered species in Winkler samples. Minor and major workers may also come to baits, where they are timid and rapidly disappear into the litter when disturbed. In spite of its ubiquity in Winkler samples, I have never found a nest. Queens are relatively common in Winkler samples, suggesting they most likely nest in small bits of rotten wood in the litter. But it is also possible they have subterranean nests.
Specimens in Winkler samples often exhibit variable color, ranging from uniformly dark brown, to somewhat mottled, to a paler dirty brown. It is as though workers tan slowly or begin foraging before fully tanned.
Minor worker: head length 0.41mm, head width 0.38mm, scape length 0.32mm, Webers length 0.46mm (n=1). Head flattened behind; mesonotal suture absent; propodeal spines medium length; face and mesosoma uniformly foveolate; first gastral tergum smooth and shining; about 16-20 setae on promesonotal dorsum, medium length, flexuous; setae on gastral dorsum medium length, somewhat stiff; hind tibia with or without long erect setae in addition to underlying suberect pubescence; color red brown.
Major worker: head length 0.78mm, head width 0.75mm, scape length 0.34mm (n=1). Face rugose foveolate throughout; rugae reticulate on posterior half, increasingly longitudinal and subparallel on anterior half; hypostomal margin gently curved; median tooth small; lateral teeth pointed, stout, about one third distance from midline to recessed teeth flanking mandible bases; dorsal pilosity abundant; head with abundant suberect setae projecting from sides of head in face view.
Similar species: rectisentis
: in the Central American highlands from Chiapas to Nicaragua there is often an abrupt transition from harrisonfordi
at the lower limit of cloud forest to rectisentis
being dominant in the cloud forest. Minor worker: postpetiole larger, more trapezoidal in dorsal view; hind tibia more pilose, with erect setae; sympatric harrisonfordi
has smaller postpetiole, lacks erect setae on hind tibia. Major worker: head generally larger, less depressed vertex lobes; postpetiole proportionally longer and narrower in dorsal view.
Biotopo El Quetzal in Guatemala does not have rectisentis
, but does have a dominant form of harrisonfordi
that is larger, more heavily sculptured than any other harrisonfordi
. This is a possible case of character displacement.specularis
: this species is broadly sympatric with harrisonfordi
. Minor worker: hind tibia with 2-3 long erect setae in addition to more appressed pubescence; propodeal spines larger.karolmorae
: in the Atlantic lowlands of Costa Rica and Nicaragua this species is broadly sympatric with harrisonfordi
. Minor worker: clypeus punctate versus smooth and shining; promesonotum somewhat box-like and dropping abruptly to metanotal groove versus box-like but not dropping as abruptly. Major worker: head in lateral view deep, with strongly convex dorsal surface, versus head relatively flatter in lateral view, with less convex dorsal surface. flavens: this species is broadly sympatric with harrisonfordi. Minor worker: color lighter yellow brown; postpetiole smaller in dorsal view. Major worker: color similar to minor; vertex lobes smooth and shiny; postpetiole narrower, more trapezoidal.
Longino, 6 Nov 2013 notes: DNA barcoding data show several clusters. These show some geographic cohesion but I cannot find morphological correlates. DNA-6: Chiapas, Peten, Izabal, La Ceiba; mostly lowland, highest specimens 950m at Nahá. DNA-3: mostly a cloud forest dark form, from La Muralla, Sierra Agalta, Cusuco, Kilambé, but also lowland lighter form from La Mosquitia and near La Ceiba. DNA-2: variable dark to lighter form at La Mosquitia lowlands, and upper elevations of Cerro Musun in Nicaragua. DNA-4: lowland form, La Mosquitia and La Selva in Costa Rica. DNA-5: mostly a dark montane form from La Union Guatemala and Azul Meambar Honduras. One anomalous dark collection from Cerro Cahuí, Guatemala. This is a single baiting sample, among many samples that match DNA-6 form, and I worry that this could be a vial mix-up. La Union and Cerro Cahuí were part of the same sampling program, with Cerro Cahuí sampled a few weeks after La Union. Pheidole specularis
is embedded within the P. harrisonfordi
There is geographic variation.
Lowland populations in the peripheral part of the range - Chiapas, Costa Rica, Panama - have the minor with uniform mesosomal foveolation; dorsal pilosity thin, flexuous, short; postpetiole small. Major with promesonotal groove weakly impressed. Hind tibia lacking erect setae in northern part of range, variably present in Honduran (Las Marias), Costa Rican populations. This form matches the synonym ruida
, from Panama.
Lowland populations in Guatemala around the Motagua fault (near Morales), from parts of Honduras, and from Veracruz, Mexico, have the minor with foveolation becoming faint on side of propodeum. The major worker looks the same as the Chiapas, Costa Rica, and Panama material. This form matches the type of harrisonfordi
(from near Lago Yohoa in Honduras) and the synonym prolixa
(from Veracruz, Mexico).
Lowland populations from the Peten (e.g. Tikal National Park area) often have the minor with dorsal setae slightly stiffer, more blunt-tipped. The major of this form has a more strongly impressed promesonotal groove; dorsal setae sparser and stiffer, more blunt-tipped; side of head with more extensive foveolation, albeit faint; in contrast other forms have a smooth shiny patch on side of head. In the Tikal area, there seems to be continuous variation from the typical form to this stiff-seta form.
In montane areas, minors and majors are darker, larger, and more heavily sculptured. Examples are coast range of Chiapas, other Chiapas highlands, Guatemala highlands, Costa Rican highlands.
Taxonomic Treatment (provided by Plazi)
Wilson, E. O., 2003, Pheidole in the New World. A dominant, hyperdiverse ant genus., Cambridge, MA: Harvard University Press: 433, (download)
Longino, J. T., 2009, Additions to the taxonomy of New World Pheidole (Hymenoptera: Formicidae)., Zootaxa 2181, pp. 1-90: 37, (download)
Specimen Habitat Summary
Found most commonly in these habitats: 428 times found in cloud forest, 283 times found in mature wet forest, 167 times found in tropical rainforest, 146 times found in tropical moist forest, 104 times found in 2º wet forest, 103 times found in mesophyll forest, 54 times found in montane wet forest, 52 times found in lowland wet forest, 49 times found in 2º lowland tropical rainforest, 46 times found in ridgetop cloud forest, ...
Found most commonly in these microhabitats: 1333 times ex sifted leaf litter, 400 times at bait, 22 times Hojarasca, 18 times forest litter, 5 times Wet forest. Ex sifted leaf litter., 13 times sifted litter, 2 times Hojarasca., 9 times ex sifted litter from forest floor, 8 times ex sifted leaf litter on ground, 5 times Hojarasca, mature forest, level, 5 times beating vegetation, ...
Collected most commonly using these methods: 1135 times MiniWinkler, 395 times Baiting, 91 times Winkler, 136 times MaxiWinkler, 44 times Berlese, 37 times Mini Winkler, 10 times bait, 23 times Night MiniWinkler, 5 times Beating, 4 times Pan Trap, 4 times Berlese/Winkler, ...
Elevations: collected from 10 - 1925 meters, 693 meters average
Type specimens: holotype Pheidole tenebra: jtlc000016551; paratype Pheidole harrisonfordi: jtlc000016399; paratype Pheidole prolixa: jtlc000016499; paratype Pheidole ruida: jtlc000016513
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