The Grey-tailed Mountaingem was split from the White-throated Mountaingem. HBW uses the term 'parapatry' to describe these two species, meaning living in adjacent areas. The point of intersection is right along the Costa Rica/Panama border. This bird is about 15-20 kilometers inside the White-throated range, but has a blue crown more consistent with the Grey-tailed. But the white belly and dark ear point to White-throated. I am guessing they haven't worked out the details of this split. Some have grouped all of these Mountaingems as one species, the Variable Mountaingem.
Africa (entire continent rather than south of Sahara)
AN
Antarctica
AO
Atlantic Ocean
AU
Australasia (Wallacea (Indonesian islands east of Wallace's line), New Guinea and its islands, Australia, New Zealand and its subantarctic islands, the Solomons, New Caledonia, and Vanuatu)
PAL
Eurasia (Europe, Asia from the Middle East through central Asia north of the Himalayas, Siberia and northern China to Japan)
IO
Indian Ocean
LA
Latin America (Middle and South America)
MA
Middle America (Mexico through Panama)
NA
North America (includes the Caribbean)
NO
Northern oceans
OR
Oriental Region (South Asia from Pakistan to Taiwan, plus Southeast Asia, the Philippines, and Greater Sundas)