Dendrophidion percarinatum (Cope) is redefined on the basis of standard and new characters to distinguish it from two new South American species with which it has previously been confused. The redefined D. percarinatum is distributed from Honduras through Central America to western Colombia, with a seemingly outlying locality in extreme western Venezuela. One new species, D. prolixum, is sympatric with D. percarinatum at a few localities in central western Colombia and the distribution of the new species continues southward into northwestern Ecuador. A second new species, D. graciliverpa, occurs throughout western Ecuador, where its distribution extensively overlaps that of D. brunneum (Günther). Hemipenes of the two new species are unusually long and slender (gracile morphotype), a morphology distinct from other described Dendrophidion hemipenes, which are shorter and more robust (robust morphotype). Additionally, the new species differ from D. percarinatum in color patterns but not in standard scutellation characters such as segmental counts. Similarly, the two new species differ from one another in coloration but not in scutellation or hemipenial morphology. Hemipenes of D. percarinatum and the new species are described in detail. The holotype of D. brunneum is redescribed to ensure the proper application of that name. New specimens document the widespread occurrence of D. brunneum in the lowlands of western Ecuador and apparent extensive pattern polymorphism, including unicolor, striped, crossbanded, and punctate forms; more data on coloration in life are needed. Some previous records of “D. percarinatum” from interandean valleys of the Río Cauca/Magdalena system are from mistaken identities. However, several specimens from the Río Magdalena resemble D. percarinatum in scutellation but differ in color pattern; their status needs further study.

Dendrophidion percarinatum (Cope) se redefine sobre la base de caracteres estandarizados y nuevos para distinguirlo de dos nuevas especies sudamericanos con que se confundieron anteriormente. El redefinido D. percarinatum se encuentra desde Honduras por América Central hasta el oeste de Colombia, con una localidad aparentamente alejada en el extremo occidental de Venezuela. Una nueva especie, D. prolixum, es simpátrica con D. percarinatum a pocas localidades en el centro-occidental de Colombia; la distribución de la nueva especie continua hacia el sur hasta el noroeste de Ecuador. Una segunda nueva especie, D. graciliverpa, occurre en todo del Ecuador occidental, donde su distribución traslapa la distribución de D. brunneum (Günther). Los hemipenes de ambas nuevas especies son exceptionalmente alargados y delgados (morfotipo esbelto). Es una morfología distinta de los otros hemipenes de Dendrophidion, que son más corto y robusto (morfotipo robusto). Además, las nuevas especies se distinguen de D. percarinatum por la coloración pero no se distinguen en caracteres estandarizados de escutellación como cuentas segmentales. De modo parecido, las dos nuevas especies se distinguen por coloración pero no por la escutellación ni la morfología de los hemipenes. Se describen los hemipenes de D. pe