The Jamaican Parakeet (Eupsittula nana) is considered by some authorities as a separate species but other authorities consider it a (nominate) subspecies of the Olive-throated Parakeet (Eupsittula nana).
The Jamaican Parakeet is restricted to Jamaica.
The very similar Aztec Parakeet (Eupsittila astec) which is sometimes considered as a separate species and sometimes as a subspecies of the Olive-throated Parakeet occurs from north-eastern Mexico through the Yucatan Peninsula and along the Caribbean slope of Central America as far south as north-western Panama.
Until a definitive decision has been made, I consider them as two distinct species.

Tamarind Great House B&B garden, Saint Mary, Oracabessa, Jamaica, 21 January 2018