The Ontogeny of Pseudis platensis (Anura, Hylidae): Heterochrony and the Effects of Larval Development on Postmetamorphic Life

FABREZI, M; QUINZIO, S. I.; GOLDBERG, J.

JOURNAL OF MORPHOLOGY

Año: 2010 vol. 271 p. 496 - 510

0362-2525

We studied the giant tadpole of Pseudis platensis and describe its delayed metamorphic transformations, and absence of postmetamorphic growth of the skeleton. We address questions about derived patterns of life cycles and the role of the heterochrony during the metamorphosis in anurans. Using anatomical methods, we provide new data on the development of reproductive organs, the digestive system and the integument. We also provide estimates of tadpole age obtained from ontogenetic series of Pseudis platensis. Our results indicate that at the end of metamorphosis, the adult skin is completely differentiated, including the calcified dermal layer; the testis has seminiferous tubules with spermatogonia, spermatocytes, and spermatids; ovarian sacs present previtellogenic ova; and the adult digestive tract is fully formed. The froglets differ from adults only in being unable to reproduce. The entire life cycle of P. platensis can occur in 4 years. In the first year, larval development, growth to adult size, and gonad differentiation are completed. Long larval development rather than size of the tadpoles seems to be involved in the absence of juvenile stages.