title: Comparative brain morphology of Neotropical parrots (Aves, Psittaciformes) inferred from virtual 3D endocasts.
abstract: Psittaciformes are a very diverse group of non-passerine birds, with advanced cognitive abilities and highly developed locomotor and feeding behaviours. Using computed tomography and three-dimensional (3D) visualization software, the endocasts of 14 extant Neotropical parrots were reconstructed, with the aim of analysing, comparing and exploring the morphology of the brain within the clade. A 3D geomorphometric analysis was performed, and the encephalization quotient (EQ) was calculated. Brain morphology character states were traced onto a Psittaciformes tree in order to facilitate interpretation of morphological traits in a phylogenetic context. Our results indicate that: (i) there are two conspicuously distinct brain morphologies, one considered walnut type (quadrangular and wider than long) and the other rounded (narrower and rostrally tapered); (ii) Psittaciformes possess a noticeable notch between hemisphaeria that divides the bulbus olfactorius; (iii) the plesiomorphic and most frequently observed characteristics of Neotropical parrots are a rostrally tapered telencephalon in dorsal view, distinctly enlarged dorsal expansion of the eminentia sagittalis and conspicuous fissura mediana; (iv) there is a positive correlation between body mass and brain volume; (v) psittacids are characterized by high EQ values that suggest high brain volumes in relation to their body masses; and (vi) the endocranial morphology of the Psittaciformes as a whole is distinctive relative to other birds. This new knowledge of brain morphology offers much potential for further insight in paleoneurological, phylogenetic and evolutionary studies.
authors.affiliation: Cátedra de Histología y Embriología Animal, Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, Buenos Aires, Argentina.|Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina.
authors.forename: Julieta
authors.initials: J
authors.lastname: Carril
authors.affiliation: Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina.|Centro de Investigaciones en Ciencias de la Tierra (CICTERRA), CONICET-UNC, Córdoba, Argentina.
authors.forename: Claudia Patricia
authors.initials: CP
authors.lastname: Tambussi
authors.affiliation: Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina.|Centro de Investigaciones en Ciencias de la Tierra (CICTERRA), CONICET-UNC, Córdoba, Argentina.|Centro de Investigaciones Paleobiológicas (CIPAL), Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de Córdoba, Córdoba, Argentina.
authors.forename: Federico Javier
authors.initials: FJ
authors.lastname: Degrange
authors.affiliation: Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina.|Departamento de Ecología, Genética y Evolución, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina.
authors.forename: María Juliana
authors.initials: MJ
authors.lastname: Benitez Saldivar
authors.affiliation: Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina.|División Paleontología Vertebrados, Museo de La Plata, Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, Buenos Aires, Argentina.
authors.forename: Mariana Beatriz Julieta
authors.initials: MB
authors.lastname: Picasso
mesh_terms: D000717:Anatomy, Comparative / Q000379:methods*; D000818:Animals; D005075:Biological Evolution; D001921:Brain / Q000033:anatomy & histology*; D021621:Imaging, Three-Dimensional / Q000379:methods; D059906:Neuroimaging / Q000379:methods; D010311:Parrots / Q000033:anatomy & histology*; D010802:Phylogeny
keywords: 3D brain reconstructions; Aves; character mapping; endocranial morphology; geometric morphometrics