Developmental changes of the fore- and hind-limbs in the fetuses of the southern minke whale, Balaenoptera acutorostrata.

ABSTRACT

15 fetuses of southern minke whale, Balaenoptera acutorostrata (from 8.2 mm C.R.L. to 38.9 mm C.R.L.), obtained from the Kyodo whale company in Japan (in whaling seasons from 1982 to 1986), were used for the present study. The fore-limb first appears in the 11.4 mm fetus, and the hind-limb in the 15.3 mm fetus. The fore-limb develops progressively during gestation, while the hind-limb disappears by the 38.9 mm fetus. The critical period of limb development in southern minke whale was shown to be at a stage between that in the small sized species; Common Porpoise, Phocoena communis and Striped Dolphin, Prodelphinus caeruleoalbus, and in large one; Humpback Whale, Megaptera nodusa.