Variation in vertebral number and its morphological implication in the South American galaxiid, Galaxias platei
BARRIGA, JUAN PABLO; MILANO, DANIELA; CUSSAC, VICTOR ENRIQUE
JOURNAL OF FISH BIOLOGY
WILEY-BLACKWELL PUBLISHING, INC
Lugar: Londres; Año: 2013 vol. 83 p. 1321 - 1333
Variation in the vertebral number of Galaxias platei was examined in this study, which spanned the entire distribution range of the species (from 40º to 55º S). The mean vertebral number (MVN) increases towards high latitudes, i.e. Jordan´s rule is applicable to this species. However, due to the wide geographic variation of the species, not only in latitude but also in altitude, the most explicative variable for MVN was mean winter air temperature, showing negative dependence. Morphological data suggest that the increment in vertebral number lies in the pre-pelvic region of the trunk and in the caudal region, but not in the segment between pelvic fin insertion and the anus. Since these alterations in body shape have important consequences for hydrodynamics and swimming performance, vertebral number variation in G. platei also holds implications for both individual and population fitness.