Reconstrucción ancestral del ojo parietal en lagartos (Orden: Sauria) de Colombia

Abstract

The parietal eye is an organ commonly found in different species of animals, whose function has been associated with the pineal gland acting as a photoreceptor and hormone producer for thermoregulation (Tosini, 1997). Over time, the parietal eye in reptiles has been studied by different authors who cover its physiology, structure and evolution; An example is the study carried out by Steyn (1960), who demonstrated that the sensory cells of the parietal eye in Cordylus polyzonus are similar to the sensory cells of the lateral eyes of vertebrates (Dodt, 1973). Another example is the study carried out by Smith and collaborators (2018), in which they talk about the evolution of a fourth eye in an extinct lizard. Specifically, the appearance and evolution of the parietal eye in reptiles can be covered by analyzing the evolutionary relationships (ancestor-descendant) of this taxon. This type of relationship is key in the study of comparative biology and biological evolution. In addition, they are reconstructed with morphological and/or molecular data from extinct and/or existing species that help to understand beyond phylogenetic systematics. This implies that the phylogenetic relationships of organisms contain not only ancestor-descendant information, but also allow infer the evolutionary path of traits presented by these species. (Ibañez & Mendez, 2014). From a methodological point of view, comparative phylogeny allows inferring “ancestral states” of traits (Ibañez & Mendez, 2014). For these inferences, the evolutionary relationships of the species must be taken into account, since their data are not statistically independent; This is then, the field of phylogenetic comparative methods, a discipline that is in charge of studying evolutionary processes through macroevolutionary times using phenotypic data of species and their evolutionary relationships. These methods are based on intensive computational statistics, which are carried out mostly in the R computational environment (Revell, 2016). In Colombia, there are 263 species of lizards reported (Uetz & Etzold, 2022) and it is not known exactly which of them have an eye. parietal eye, nor the reason why it is not found in this entire taxon, so in this study the ancestral reconstruction of the parietal eye has been proposed.