ALT Landmark scheme shown on the left side of a representative catfish. Paired landmarks (triangles) were digitized as two separate right and left landmarks, while medial landmarks (circles) were digitized once. Colors correspond to body regions analyzed for differential rates and modularity: purple = mouth (mouth anterior, mouth left and right, mouth posterior); red = snout (tip of snout, anterior nares, posterior nares); yellow = cranial region (anterior, medial, posterior, and lateral points of the eyes, dorsal and ventral extent of the opercle opening, posterio-medial supraoccipital); green = abdomen (dorsal-, pectoral-, and pelvic-fin origins, dorsal- and pectoral-fin tips); blue = tail (dorsal-fin insertion, cloaca, anal-fin origin and insertion, dorsal and ventral procurrent caudal-fin rays, end of vertebral column). Black dots indicate adipose-fin landmarks, which are absent in many species and not included in comparative analyses.