The transect runs along the 10th Latitude of Peru with an extension of 110 airline km (west-east) and 50 airline km (north-south), respectively the Latitude being the middle of the transect. From west to east the transect passes through the coastal desert, the mountain steppe, and the puna. During approximately four months of fieldwork 18 localities in the Departamento Ancash were visited within the transect. 29 species (amphibians: 8, reptiles: 21) were recorded, belonging to 10 families (amphibians: 4, reptiles: 6) and 19 genera (amphibians: 6, reptiles: 13). Two species of reptiles were new to science and another two species of reptiles were recorded in Departamento Ancash for the first time (published elsewhere). For all recorded species, information about their horizontal, vertical and ecoregional distribution and political endemism is presented as well as taxonomic and ecological notes. The herpetofaunal communities of the coastal desert and the mountain steppe have 8 species in common and a Coefficient of Biogeographic Resemblance-Index (CBR) of 0.46, therefore being more similar than the herpetofauna communities of the mountain steppe and the puna, which have 4 species in common and a CBR of 0.32. The herpetofaunal communities of the coastal desert and the puna do not have any species in common. The herpetofauna of the mountain steppe has the highest number of species (19), the highest relative abundance of species and the highest number of endemic species (12).