Geometric morphometrics reveal complex shape variation patterns at different geographic scales in the patagonian gastropod Trophon geversianus

NIETO-VILELA, ROCÍO AIMÉ; VRDOLJAK, JUAN; GIULIANELLI, SEBASTIÁN; BIGATTI, GREGORIO; MÁRQUEZ, FEDERICO

EVOLUTIONARY ECOLOGY

SPRINGER

Lugar: Berlin; Año: 2021

0269-7653

Environments with strong gradients in physical conditions, such as rocky intertidal, induceanimal morphological strategies to face them. The gastropod Trophon geversianus inhabitwithin the intertidal and subtidal habitats of Patagonian rocky shores. Although there is awide knowledge of the phenotypic differences of this species regarding habitats (i.e., intertidal/subtidal), little is known about the interaction between habitat and latitude. Here, westudied form variation (size and shape) by using 3D geometric morphometric of T. geversianusshells from alive gastropods and analyzed the phenotypic effect from micro-scale(habitat), macro-scale (latitude), and the interaction habitat-latitude (site). Lastly, we testedthe classification accuracy of the shape variable for each predictor variable and a syntheticvariable (from a cluster analysis). We found that habitats and sites had the greatest influenceon shape variation. Moreover, we found that the largest shell sizes were more likelyto be located in subtidal habitats. Also, the size differences between sites were not negligible.Finally, habitat demonstrated the highest classification accuracy for shape, even higherthan genetically determined (sex) and synthetic variables. We found that the gastropodsfrom the intertidal habitat presented a globular morph with shorter spire and larger relativesize of the shell aperture, while subtidal gastropod showed an elongated morph, withsmaller aperture and longer spire. We present evidence of the complexity of size and shapevariation in T. geversianus, highlighting that site-dependence on shape variation must beconsidered in geometric morphometrics studies at a latitudinal scale