This small hummingbird form ranges from the Yucatán Peninsula to Belize. Adult males have a shining violet crown and elongated central tail feathers.
Adult males have a metallic violet crown and green to bronze-green upperparts. The central tail feathers are elongated and the underside is gray. Females are similar but have shorter central tail feathers; the pampa form is described as darker below with an entirely black bill.
During the first feather change, 0–6 inner feathers covering the wing were replaced (mean 1.31). Young birds have dull green feathers over the wings; later feathers are shiny green. Tail shape also differs by sex. Adult males have long green-and-black tails with a stepped outline and rounded tips. Females have rounder tails, with pale gray tips on the outer two feathers. Some young males had narrow, pointed tail feathers, and white on the outer pair varied.
In young males, the shafts supporting the outer wing feathers thickened once the second molt replaced their juvenile feathers. Before then, their tails could look intermediate or female-like. Fine lines across the beak were gone by the time the feathers reached adult form.
An extinction-risk assessment has not been added yet.