A huge thank you to Dr. Nathan Muchhala for sharing his photographs of a mammalian pollinator in action to round out the pollinator series.
The flower of the plant species, Centropogon nigricans, is exclusively pollinated by the tube-lipped nectar bat, Anoura fistulata. In other words, this is an example of obligate pollination. It's also thought to be a prime example of co-evolution (PDF). Dr. Muchhala described Anoura fistulata in a 2005 paper, so this bat species was unknown to science as recently as three or four years ago. Native to the outer slopes of the Andes in Ecuador, Anoura fistulata has the longest tongue relative to its body length of any mammal -- so long, in fact, that it is necessary for it to retract its tongue into its rib cage.
The story of the discovery was widely covered in the press in late 2006, so here are a few places to spend some time reading: Floral Long-Necks and Bat Sippers via the Human Flower Project, the transcript of a Nature podcast with Dr. Muchhala about Anoura fistulata, and A New World Record from Bat Conservation International.
Dr. Muchhala has a series of photographs of bat-pollinated flowers (and related bats) here: Bat Pollination in Cloud Forests.
As for the plant, Centropogon nigricans, there's not much to be found about it online, other than what is written about it in relation to this story, including: "Specialization on one species of pollinator is exceedingly rare in angiosperms, and Centropogon nigricans is the only example known in flowers pollinated by bats." The genus Centropogon has a distribution range that extends from Mexico south into much of South America (including Peru, Brazil, Chile and Argentina). Of the 230 described species, 65 are found in Ecuador.