VERTEBRAL MORPHOLOGY OF BOA CONSTRICTOR (SERPENTES: BOIDAE) AND THE VALIDITY OF THE MIOCENE GENUS PSEUDOEPICRATES AUFFENBERG, 1923. The vertebral morphology of the extant Neotropical snake Boa constrictor Linnaeus, is discussed on the basis of clearly described and illustrated characters that can be observed in isolated fossil vertebrae. Mid-precloacal vertebrae of B. constrictor are mainly characterized by a high neural spine; generally high and vaulted neural arch; robust and very high zygosphene, with a narrow basis; notched or concave anterior edge of zygosphene in dorsal view, without a medial protuberance or tubercle; long zygapophyseal articular facets oriented more laterally than anterolaterally, slightly inclined above the horizontal; constant presence of small paracotylar foramen; very short neural arch and vertebral centrum; and very thin, clearly defined, and prominent haemal keel. Posterior precloacal vertebrae are longer (neural arch and vertebral centrum) and have shorter zygapophyses, thinner zygosphene, and broader and less prominent haemal keel than the mid precloacal vertebrae. Based on the knowledge of the morphology of the vertebrae of B. constrictor and its intracolumnar and intraspecific variation, the genus Pseudoepicrates from the Miocene of Florida is synonymyzed with Boa. This implies that this genus reached the Greater Antilles and Florida during the Miocene, becoming later extinct in these areas.