Otolith shape lends support to the sensory drive hypothesis in rockfishes

Abstract

The sensory drive hypothesis proposes that environmental factors affect both signalling dynamics and the evolution of signals and receivers. Sound detection and equilibrium in marine fishes are senses dependent on the sagittae otoliths, whose morphological variability appears intrinsically linked to the environment. The aim of this study was to understand if and which environmental factors could be conditioning the evolution of this sensory structure, therefore lending support to the sensory drive hypothesis. Thus, we analysed the otolith shape of 42 rockfish species (Sebastes spp.) to test the potential associations with the phylogeny, biological (age), ecological (feeding habit and depth distribution) and biogeographical factors. The results showed strong differences in the otolith shapes of some species, noticeably influenced by ecological and biogeographical factors. Moreover, otolith shape was clearly conditioned by phylogeny, but with a strong environmental effect, cautioning about the use of this structure for the systematics of rockfishes or other marine fishes. However, our most relevant finding is that the data supported the sensory drive hypothesis as a force promoting the radiation of the genus Sebastes. This hypothesis holds that adaptive divergence in communication has significant influence relative to other life history traits. It has already been established in Sebastes for visual characters and organs; our results showed that it applies to otolith transformations as well (despite the clear influence of feeding and depth), expanding the scope of the hypothesis to other sensory structures.

Identifying sagittal otoliths of Mediterranean Sea gobies: variability among phylogenetic lineages

“…In conclusion, we have demonstrated that shape contours of gobiid otoliths can be used to automaticate identification of specimens to genus and even species. Moreover, we have detected an apparent phylogenetic clustering in the distinctive otolith patterns of the different lineages, as occurs in other fishes (Sadighzadeh et al, 2014), such shape patterns can help with understanding the evolution of the group (Tuset et al, 2016). This study were financed by projects "AFORO3D" (Ref.…”

“…Tuset et al . () used otolith shape to correctly identify 58.1% of 42 rockfish species (Sebastidae) and Sadighzadeh et al . () used otolith shape to correctly identify 65.5% of 12 snapper species (Lutjanidae).…”

“…Recently, Schwarzhans () observed, within the genus Hymenocephalus Giglioli 1884 , trends of parallel polarity in certain head and otolith features and discussed the connection with both structures. In any case, a relationship makes sense, because the head shape is, directly or indirectly, related to both feeding habits (Hobson, ) and otolith shape (Tuset et al, ).…”

“…In fact, there is an inverse association between identification success and number of possible species in any shape-based identification analysis. Tuset et al (2016) used otolith shape to correctly identify 58.1% of 42 rockfish species (Sebastidae) and Sadighzadeh et al (2012) used otolith shape to correctly identify 65.5% of 12 snapper species (Lutjanidae). By contrast, when analyses are limited to only two to five species, the percentage of correct classification noticeably increases to c. 70% (Tuset et al, 2006.…”

Enigmatic ear stones: what we know about the functional role and evolution of fish otoliths

“…Studies on the ecomorphology and functional morphology of inner ear components should complement each other. Combined data sets including ecological, eco‐acoustical, life‐history, morphological (otoliths) and physiological (auditory) traits, in combination with phylogenetic information (Wainwright et al, ; Tsuboi, Gonzalez‐Voyer & Kolm, ; Tuset et al, ), would allow deeper insights into the potential selective forces affecting otolith morphology, including potential co‐evolution between (or developmental interdependencies of) otolith morphology and other inner ear components, as well as phylogenetic constraints on otolith evolvability. For example, Tuset et al .…”