Pj. Fernandez et Jt. Bagnara, OBSERVATIONS ON THE DEVELOPMENT OF UNUSUAL MELANIZATION OF LEOPARD FROG VENTRAL SKIN, Journal of morphology, 216(1), 1993, pp. 9-15
The ontogeny of ventral pigmentation of two species of leopard frog, R
ana pipiens and R. chiricahuensis, was examined by light microscopy an
d transmission electron microscopy to reveal how the unusual melanisti
c ventral pigmentation of R. chiricahuensis is achieved at the cellula
r level. Ventral skin of R. pipiens is always white. Ventral skin of a
dult R. chiricahuensis is white when frogs are background-adapted to a
white substrate, but ventral skin becomes nearly as dark colored as t
he dorsal skin when frogs darken in response to a black background. Sk
in samples from tadpoles of both species, newly metamorphosed frogs, a
nd adult frogs were analyzed for chromatophore composition and distrib
ution. Ventral skin of R. pipiens larvae, newly metamorphosed frogs, a
nd adults and of R. chiricahuensis larvae was white due to abundant ir
idophores and no melanophores. Melanophore density in the ventral inte
gument of R. chiricahuensis was 9.1 +/- 2.8/mm2 in newly metamorphosed
frogs and 87.0 +/- 4.8/MM2 in adult frogs. Pigment within ventral mel
anophores migrated during physiological color change during background
adaptation.