Thursday, September 8, 2011

Remarkable Reproductive Behavior in Dwarf Hemiphractids.

Flectonotus fitzgeraldi. Female w/eggs. JCM
Five species of Dwarf Marsupial Frogs of the genus Flectonotus are found in Northern South America and Brazil. It now appears that they from two groups of species and each group forms a genus. These unique little frogs have females carry their eggs in dorsal pouches (hence the name marsupial) until the tadpoles hatch, at which time the female frogs deposit the tadpoles in leaf axial pools. Duellman et al. (2011) report observations on the reproductive behavior of Fritziana goeldii (Brazil) and Flectonotus pygmaeus (Venezuela) females that shows significant differences. A pair of goeldii goes into amplexus, the female replaces a mucus mass that is beat into foam by the male's hind feet, and while this is happening the skin on the female's back is stretched out by the male's front feet. As the eggs are laid, the male fertilizes them and moved them forward into the foam mass. Once the eggs are laid, the male abandons the female and she is left with a foam mass and the eggs on her back. Over the next 4 to 8 days the egg sac forms, apparently by her skin growing around the egg sac. The female did not start to forage for food until the sac was covered. At this time the eggs cannot be removed without injuring the female. The embryos develop during the next 17-23 days, at which time the female enters a water filled bromeliad tank and sloughs off the entire egg sac. Skin folds are visible for a few hours, but then disappear. The tadpoles escape the egg sac and feed on its remains as well as on other debris in the bromeliad tank, but tads that ate nothing metamorphosed in the same about of time. Metamorphosis is complete within the next 21 -25 days

Flectonotus pygmaeus, on the other hand actually has a fold of skin that forms a pouch and during amplexus, the female releases the mucus secretion, the male beats it into a foam, and as the eggs are laid, the male pushes the eggs into the skin folds - the pouch. The eggs are closely packed together but there is no egg matrix, and the eggs can be removed- they are not attached to each other. The female started to forage within 24 hours. After 23-26 days egg sac starts to split and the female transfers the tads to a leaf axial pool. She submerges a third of her body and the tadpoles swim out. The tadpoles do not feed, they continue to metamorphosis using stored yolk for another 11-17 days.

The authors remove the three species of Brazilian Flectonotus and reassign them to the genus Fritziana. The entire article can be found on-line.

Citation
Duellman, W.E., K.-H, Jungfer, and D. C. Blackburn 2011. The phylogenetic relationship of geographically separated “Flectonotus” (Anura: Hemiphractidae), as revealed by molecular, behavioral, and morphological data. Phyllomedusa, 9:15-29

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