Buoyancy of sub-Antarctic notothenioids including the sister lineage of all other notothenioids (Bovichtidae)

D. A. FERNÁNDEZ; S. G. CEBALLOS; G. MALANGA; C. C. BOY; F. A. VANELLA

POLAR BIOLOGY

SPRINGER

Lugar: Berlin; Año: 2012 vol. 35 p. 99 - 106

0722-4060

The radiation of notothenioid fishes (Perciformes)in Antarctic waters was likely the result of an absenceof competition in the isolated Antarctic waters and keytraits such as the production of antifreeze glycoprotein andbuoyancy modifications. Although notothenioids lack aswim bladder, the buoyancy of Antarctic species, rangingfrom neutrally buoyant to relatively heavy, corresponds todiverse life styles. The buoyancy of South American notothenioidshas not been studied. Static buoyancy wasmeasured in adult notothenioids (n = 263, from six speciesof the sub-order Notothenioidei, families Bovichtidae,Eleginopidae, Nototheniidae, and Harpagiferidae) from theBeagle Channel. Measurements were expressed as percentagebuoyancy (%B). Buoyancy ranged from 3.88 to6.96% (median, 4.0–6.7%), and therefore, all species couldbe considered benthic consistent with previous studiesthat found that neutral buoyancy in notothenioids is rare.Harpagifer bispinis, Patagonotothen cornucola, and Cottopercagobio were significantly less buoyant than Paranototheniamagellanica. The buoyancy values of mostspecies were concordant with known habitat preferences.These data, especially the data of C. gobio (sister lineage ofall other nototehnioids) and E. maclovinus (sister lineage ofthe Antarctic clade of notothenioids), could be useful forunderstanding the diversification of this feature during thenotothenioid radiation.