sentences:  "Isthmohyla lancasteri" was described by Thomas Barbour in 1928, based a single specimen (the holotype) collected by C. R. Lancaster—and after whom the species is named.The species is very variable; however, high-altitude populations that were first ascribed to this species were in 1996 recognized as a new, distinct species, "Isthmohyla calypsa".Males grow to about and females to about in snout–vent length.