The main objective of this work was to carry out the external morphology characterization of 60-days gestation Myocastor coypus (coypu) fetuses since this stage could be considered a crucial point in the prenatal development in this species. Fourteen fetuses out of three litter were analised. Gestational sacs weighing 3.81 ± 0.27 g showed an elliptical shape with the larger axis along the direction of the uterus. The average weight of fetuses was 1.13 ± 0.19 g, the head-to-tail lenght was 1.99 ± 0.87 cm, the cephalic lenght was 1.01 ± 0.37 cm, and the biparietal diameter was 0.63 ± 0.06 cm. Specimens showed differentiation in corporeal, limbs and tail regions; also showed interdigital membranes, well defined optical vesicles and lateral ear lobe sprouts.... |