“…Thus, these proteins have served as anatomical markers in numerous studies in all classes of tetrapods (birds: Roth, Baetens, Norman, & García‐Segura, ; Rogers et al, ; Puelles, Robles, Martínez‐de‐la‐Torre, & Martínez, ; Belekhova et al, ; reptiles: Dávila, Padial, Andreu, Real, & Guirado, ; Dávila, Guirado, & Puelles, ; Yan, Tang, & Carr, ; Song, Wang, Carr, Dai, & Tang, ; amphibians: Necchi, Soldani, Pisu, Bernocchi, & Scherini, ; Milán & Puelles, ; Morona & González, ; Morona, López, & González, ). In particular, analysis of the distribution of CB‐ and CR‐containing cells and fibers has been widely conducted in the brain of many fish groups to assist in the identification of regions and nuclei across species because their staining, in many cases, facilitates topological recognition of homologous structures (lampreys: Pombal & Puelles, ; Megías, Álvarez‐Otero, & Pombal, ; elasmobranchs: Rodríguez‐Moldes et al, ; Rodríguez‐Moldes et al, ; Anadón et al, ; all groups of actinopterygians: Díaz‐Regueira & Anadón, ; Castro, Becerra, Manso, & Anadón, ,b; Northcutt, ; Jadhao & Malz, ; Graña, Huesa, Anadón, & Yáñez, ; Graña, Folgueira, Huesa, Anadón, & Yáñez, ; Deshpande & Jadhao, ).…”