We describe and name a new species of Alopoglossus (Gymnophthalmoidea: Alopoglossidae) from western Colombia (Departamentos Cauca and Valle del Cauca: Chocó biodiversity hotspot). The new taxon is morphologically similar to Alopoglossus festae and A. viridis, from which it differs in having, among other things: strongly keeled imbricated temporal scales; strongly keeled scales on dorsum of hand; rhomboid, keeled, and heavily pigmented ventral scales. Specimens of this new taxon have been sitting in museum shelves for several decades (holotype collected over 40 years ago)—thus, we discuss the relevance of biological specimen collection and the importance of reexamination of old museum records, in search of unnamed biodiversity.