nest structure, incubation and and hatching in the trinidadian leaf-frog phyllomedusa trinitatis (anura: hylidae)

New findings on nesting and hatching are reported for the leaf-nesting tree frog Phyllomedusa trinitatis. Nest height and leaf cover(one or many leaves, well or poorly covered) were very variable. Contrary to a previous report, egless jelly capsules we scattered amongst the eggs, with substancial jelly plugs located above and below the egg clutch. Plugs were composed of capsules embedded in a matrix of somewhat different composition. The upper plug acted as a barrier to water entry. Contrary to previous reports, isolated eggs could develop in aquatic media, the later stage on entry the better: Aeration and salt composition of the water influences this ability. Egg clutches developes equally well whether the covering leaves were alive or dead. Single eggs incubated in water hatched prematurely; when placed in water, eggs near hatching stage hatched within a short time; such eggs on a dry or damp substrate did not hatch till much later. The hatching of any embryo in a group appeared to act as a stimulus to neighbours to hatch. Observations ons nests with the covering leaves replaced by clingfilm showed that emergence is preceded by a lenghty period of hatching behavior, with individuals hatchins, wriggling and stimulating larger and larger groups to hatch, and releasing a frothy fluid wich leads to the dissolution of the lower jelly plug and emergence of the hatchlings. Contrary to a previous report, hatching gland cells were observable on the laterodorsal surface of the head. When hatchings emerged from the nest, they were mostly at Gosner stage 25 with gills fully resorbed. When earlier embryos were induced to hatch, they rapidly shortened their external gills. These findings are discussed in comparison with observations on the related genus Agalychnis.