The hybrids between Bufo paracnemis ♂ x Bufo arenarum ♀ are counted among tbe so called \"vital hybrids\". Our resu1ts have revealed relevant ocular anomalies in 90% of cases. In some larvae the lens is lacking in either one or both eyes (20%); in others the lens it is found in an opposite position to normal (25%) or else one normal and one different eye is formed (20%). Histological analysis reveals anomalies in the retinal area, observing flexuous movements in the pigmentary strata (5%). Eyes folded over themselves were also observed (5%). The most severe alterations produced cases of anophtalmia (10%). On occasions (5%), groupings of pigments were found instead of the eyes. l00% of the larvae were normal. The other organs show analogies to those of the larvae of Bufo paracnemis, including the dorsal pattem.
Rengel, D., Alonso, D. & Pisanó, A. (1994). Anomalías oculares en híbridos Bufo paranecmis Bufo arenarum (Anura: bufonidae). Cuadernos de Herpetología, 8 (2), pp.