Rosenberg's treefrog (Hypsiboas rosenbergi), also known as Rosenberg's gladiator frog or Rosenberg's gladiator treefrog, is a species of frog in the family of tree frogs (Hylidae) and genus of gladiator frogs (Boana) found in Costa Rica, Panama, Colombia, Trinidad and Tobago and north-western Ecuador. Its scientific name is a testimony to Mr. W. F. H. Rosenberg who collected the type series, and its common name refers to the aggressiveness of males of the species. Description The size of H. rosenbergi varies based on the population that they belong to, with individuals from the Costa Rican population being smaller in size than those from the Panamanian population. In the Panamanian population, males of H. rosenbergi measure on average 83 mm (3.3 in) in snout–vent length and females 86 mm (3.4 in). Females also tend to be heavier than males. It has partly webbed fingers and entirely webbed toes and large disks on both fingers and toes. Its skin is granulated with small warts, and yellowish, greyish, or reddish in colour, with brown or blackish marbling or spots. It also has dark worm-like markings across the dorsal surfaces of the body and limbs, with gray-white undersurfaces and a pigmented area that covers near the throat. Males tend to have more pigmented throats than females, a feature which is likely a result of hormonal control due to more pigmented individuals calling more often. Females, on the other hand, tend to contain more yellow dorsal colors than males. In addition, the female’s body wall in front of its groin is nearly transparent, a feature that allows its black eggs to be easily seen. H. rosenbergi has a pale yellow lower jaw with similar black worm-like markings as seen on the dorsal surface, and its eyes have a bronze/golden iris with black around it. However, most of their color fades to light gray or tan during the day, and most of the patterns visible also disappear. H. rosenbergi males have prepollical spines on their hands that consist of pointed spines with scythe-shaped features. The prepollical spines are used in combat and contribute to its alternative name “Rosenberg's gladiator frog”. Females also possess these spines, though they are very small, and only males have control over its position and the ability to retract its fleshy sheath to reveal the scythe-shaped parts for combat. Habitat and distribution H. rosenbergi inhabits primary and secondary forest, as well as