Allometry, function and shape diversification in the inner ear of platyrrhine primates

DEL RIO, JOAQUIN; ARÍSTIDE, LEANDRO; DOS REIS, SERGIO FURTADO; PIRES DOS SANTOS, THAÍS M.; LOPES, RICARDO T.; PEREZ, SERGIO IVAN

JOURNAL OF MAMMALIAN EVOLUTION

SPRINGER

Lugar: Berlin; Año: 2019

1064-7554

The diversification of anatomical structures with functional importance duringthe branching process of a clade is a widely studied phenomenon in evolutionarybiology. In recent years, there is a growing interest in the study of the inner ear, astructure associated with hearing, locomotion, and indirectly, with body size. Thesestudies have been particularly important in primates. The platyrrhine radiation is anideal system in which to study inner ear diversification because it is one of the majorgroups of living primates and an example of an adaptive radiation related to body sizeand ecological characteristics. In this work, we used microtomography, 3D geometricmorphometrics, and phylogenetic comparative methods to explore the pattern of shapevariation in the inner ear of platyrrhines and to assess whether this variation is relatedto size, locomotion, and vocalization. Our main results suggest that 1) diversification ofinner ear morphology was achieved early in the radiation, particularly for the shape ofthe semicircular canals and the relative size of the cochlea; 2) inner ear shapediversification is generally not associated with changes in vocalization features orlocomotion behaviors; and 3) conversely, body size is a strong predictor of inner earshape. This last result contrasts with recent studies indicating that allometry has weakeffects on platyrrhine cranial diversification and suggests complex factors driving innerear diversification in the clade.