Pheidole pegasus Sarnat 2008
Fiji

Eli Sarnat, the reigning expert on the Ants of Fiji, has just published a lovely taxonomic revision of a group of Pheidole that occur on the islands. Pheidole are found in warmer regions worldwide, but Fiji has seen a remarkable radiation of species that share a bizarre set of spines on the mesosoma. Eli sorted through hundreds of these things to determine that the group contains seven species, five of which had not previously been described. Pheidole pegasus is largest and among the most distinct of the group.  It was collected only once, from the summit of Mt. Delaikoro.

Source: Sarnat, E.M. 2008. A taxonomic revision of the Pheidole roosevelti-group (Hymenoptera: Formicidae) in Fiji. Zootaxa 1767: 1-36.