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Mexico, Belize, Costa Rica. Costa Rica: San Luis Valley near Monteverde.
The types were collected in Mexico. In Wilson's (2003) revision he reports a minor worker from Teoviscocla, near Cuichapa, Veracruz, Mexico. It was collected in 1960 by a Cornell University Field Party, at a 1600m elevation site, tropical forest with plantings of coffee. Gordon Snelling just reported another collection from Belize. He reported it on his Name that Ant website.
I know this species from only one locality in Costa Rica. In 1989 I was visiting the San Luis waterfall. The San Luis valley is on the Pacific slope below Monteverde, and near the upper part of the valley, at about 1100m, is a tall waterfall. From the base of this waterfall a major stream flows down a wooded ravine and out into the upper farms of the valley. I found several workers foraging on stones at the very edge of the stream, near the base of the waterfall. I returned in 1994 and found a few additional workers in the same circumstances.
This is a spectacular ant. When I first encountered it I didn't know where to put it. The petiole made me think of Macromischa. They sat around in my Leptothorax (now Temnothorax) drawer for over a decade, gathering dust (figuratively). In preparing the Leptothorax of Costa Rica web pages, I took a close look at them again. On close inspection of the mandibles it immediately became clear that they had the characteristic Pheidole dentition (Figure: small, large), as outlined in Bolton's key to genera. I then leafed through Wilson's revision looking at the illustrations until I found a match at ursus. On the off chance P. ursus would have some information on the web, I did a search and encountered Gordon's Name that Ant!
I still think this is a very strange Pheidole, and I hypothesize it is a very primitive one. The propodeal spines and the petiole structure look exactly like those of Pheidole primigenia Baroni Urbani, an extinct species from Miocene amber of the Dominican Republic (Baroni Urbani 1995, also see figure in Wilson 2003:12). It could be that long petioles were popular in the Miocene, but as ants increasingly dominated the terrestrial realm they became a liability (easily snipped by other ants). Long-petiolate Temnothorax could date from the same era, with a relict stronghold in Cuba and a very sparse occurrence on the MesoAmerican mainland today. Thus P. ursus could be an ancient and relict Pheidole, with a spotty distribution in mid-elevation habitats of MesoAmerica.
Baroni Urbani, C. 1995. Invasion and extinction in the West Indian ant fauna revisited: the example of Pheidole (Amber Collection Stuttgart: Hymenoptera, Formicidae. VIII: Myrmicinae, partim). Stuttg. Beitr. Naturkd. Ser. B (Geol. Palaontol.) 222:1-29.
Wilson, E. O. 2003. Pheidole in the New World: A Dominant, Hyperdiverse Ant Genus. Harvard University Press, Cambridge, Mass.
types Naturhist. Mus. Wien; Mus. Comp. Zool. Harvard.
Diagnosis A very large, unique species similar in various traits to the species listed in the heading above.
Major: very long propodeal spine, largely rugoreticulate surface of the mesosoma and dorsal surface of the head, shallowly concave profde of the posterior half of the head in side view, completely foveolate and opaque surfaces of the gastral tergites. Minor: extremely long propodeal spine and petiolar peduncle, rugoreticulate promesonotum, and somewhat narrowed occiput with a thin nuchal collar.
Measurements (mm) Syntype major: HW 2.64, HL 2.54, SL 1.22, EL 0.26, PW 1.02. Minor: HW 0.88, HL 0.86, SL 1.00, EL 0.18, PW 0.60. Color Major: body and appendages dark to blackish brown.
Minor: body concolorous blackish brown with reddish overtones; appendages, including mandibles, a lighter shade of medium reddish brown; tarsi yellowish brown.
Range In addition to the types (from "Mexico") I have seen a minor worker from near Cuichapa, Veracruz, collected at 1600 m.
Biology The Teoviscocla minor worker figured was collected in tropical forest with plantings of coffee.
Figure Upper: syntype, major. Mexico, no further locality (collected by "Prof. Bilimek"). Lower: minor. MEXICO: Santa Teoviscocla, near Cuichapa, Veracruz, 1600 m (Cornell University Mexico Field Party, August 1960). Scale bars = 1 mm.
Found most commonly in these habitats: 28 times found in cloud forest, 22 times found in mesophyll forest, 20 times found in ridgetop cloud forest, 14 times found in montane rainforest, 16 times found in mesophil forest, 4 times found in riparian forest, 4 times found in lowland tropical rain forest, 4 times found in montane wet forest, 6 times found in lowland rainforest, 7 times found in riparian mesophil for., ...
Found most commonly in these microhabitats: 80 times at bait, 28 times ex sifted leaf litter, 27 times beating vegetation, 1 times ex dead treefern petiole, 1 times nest in live-to-dead stem, 1 times nest under epiphytes, 1 times nest in base of live tree, 2 times Malaise trap, 1 times ex vine, 1 times wet forest stream edge, 1 times Stray workers at base of San Luis waterfall., ...
Collected most commonly using these methods: 78 times Baiting, 9 times search, 27 times Beating, 21 times MiniWinkler, 7 times hand collecting, 6 times MaxiWinkler, 3 times bait, 1 times sweep net, 1 times Malaise, 1 times Malaise trap, 1 times white pan trap, ...
Elevations: collected from 150 - 1675 meters, 1139 meters average