Data from: Whole-body variational modularity in the zebrafish: An inside-out story of a model species

Actinopterygians are the most diversified clade of extant vertebrates.
Their impressive morphological disparity bears witness to tremendous
ecological diversity. Modularity, the organization of biological systems
into quasi-independent anatomical/morphological units, is thought to
increase evolvability of organisms and facilitate morphological
diversification. Our study aims to quantify patterns of variational
modularity in a model actinopterygian, the zebrafish (Danio
rerio), using 3D-geometric morphometrics on osteological
structures isolated from micro-CT scans. 72 landmarks were digitised along
cranial and postcranial ossified regions of 30 adult zebrafishes. Two
methods were used to test modularity hypotheses, the covariance ratio and
the distance matrix approach. We find strong support for two modules, one
comprised of paired fins and the other comprised of median fins, that are
best explained by functional properties of subcarangiform swimming. While
the skull is tightly integrated with the rest of the body, its intrinsic
integration is relatively weak supporting previous findings that the fish
skull is a modular structure. Our results provide additional support for
the recognition of similar hypotheses of modularity identified based on
external morphology in various teleosts, and at least two variational
modules are proposed. Thus, our results hint at the possibility that
internal and external modularity patterns may be congruent.