title: Evolutionary modularity and morphological integration in the haptoral anchor structures of Ligophorus spp. (Monogenea: Dactylogyridae).
abstract: An important question in the study of phenotypic evolution is whether characters are independent of each other or behave and evolve as integrated modules. Morphological integration and modularity provide a powerful framework for the analysis of the evolution of morphological traits. We used geometric morphometrics and phylogenetically independent contrasts (PIC) to test four different modularity hypotheses in the haptoral anchors of 14 monogenean species of Ligophorus. Integration between the modular units identified was further evaluated with two-block partial least squares analysis. Roots and points represented two modules in the dorsal and ventral anchors, but modularity was not statistically supported when parasite phylogeny was accounted for, which may indicate convergent evolution related to host characteristics and gill morphology. In contrast, PIC revealed medial and lateral modules in ventral anchors only. Moreover, we found evidence for ventral and dorsal anchor pairs forming two modules, supporting the notion that they play different functional roles. Integration between all identified modules was strong. We conclude that there is modular structure in the anchors of Ligophorus spp., accounted by adaptive and phylogenetic factors acting at different levels, and ventral and dorsal anchors evolve as integrated modules with specific roles in attachment.
authors.affiliation: Marine Zoology Unit, Cavanilles Institute of Biodiversity and Evolutionary Biology, Science Park, University of Valencia, P.O. Box 22085, 46071, Valencia, Spain. arogon5@uv.es.
authors.forename: A
authors.initials: A
authors.lastname: Rodríguez-González
authors.affiliation: Marine Zoology Unit, Cavanilles Institute of Biodiversity and Evolutionary Biology, Science Park, University of Valencia, P.O. Box 22085, 46071, Valencia, Spain.
authors.forename: R
authors.initials: R
authors.lastname: Míguez-Lozano
authors.affiliation: Department of Biology, Zaporizhzhia National University, Zhukovskogo 66, 69063, Zhaporizhzhia, Ukraine.
authors.forename: V
authors.initials: V
authors.lastname: Sarabeev
authors.affiliation: Marine Zoology Unit, Cavanilles Institute of Biodiversity and Evolutionary Biology, Science Park, University of Valencia, P.O. Box 22085, 46071, Valencia, Spain.
authors.forename: J A
authors.initials: JA
authors.lastname: Balbuena
mesh_terms: D000818:Animals; D005075:Biological Evolution; D001699:Biometry; D005880:Gills / Q000469:parasitology; D010641:Phenotype; D010802:Phylogeny; D023701:Smegmamorpha / Q000469:parasitology*; D014200:Trematoda / Q000033:anatomy & histology* / Q000145:classification / Q000502:physiology
keywords: Haptor; Ligophorus spp.; Modularity; Morphological evolution; Morphological integration