Atelopus flavescens

Abstract: We investigated the genetic structure of populations of Guianan harlequin toads (genus Atelopus) and their evolutionary affinities to extra-Guianan congeners. Phylogenetic analysis of mitochondrial cytochrome b (cyt b) and NADH dehydrogenase subunit 2 (ND2) gene sequences produced well-supported clades largely corresponding to the four recognized taxa in the Guianas (Atelopus spumarius hoogmoedi, Atelopus spumarius barbotini, Atelopus franciscus, and Atelopus flavescens). Our findings suggest that the Guianan A. spumarius represent distinct evolutionary lineages that merit distinction from Amazonian conspecifics, and that the status of A. flavescens and A. franciscus is somewhat less clear. Approximately 69% of the observed genetic variation is accounted for by differences between these four recognized taxa. Coalescent-based estimates of gene flow between taxa suggest that these lineages are largely isolated from one another. Negligible rates of migration between populations and significant divergence within such close proximity suggests that although the region inhabited by these taxa is almost entirely undisturbed, significant habitat heterogeneity exists as to have produced a remarkable diversification of Atelopus within the eastern Guiana Shield. These results contradict the commonly held view of the Guiana Shield as a 'refuge' whose stability during late Tertiary and Quaternary climatic fluctuations served as a biotic reservoir. Instead, we provide evidence that climatic fluctuations during this time had a diversifying effect within the Guianan region.

Abstract: The eggs and gastromyzophorous tadpole of Atelopus flavescens have been found in a small river in French Guiana. The egg-string was fixed under a water-bathed stone below a small cascad, the tadpoles were fixed to stones by their ventral sucker in shallow and oxygeneus (7,5 mg/l O 2 ) water. The tadpole is described.

Abstract: The tadpole of Atelopus franciscus from French Guyana is described. It resembles other larvae of the genus, especially those displaying a color pattern of symmetrical light marks. Among them, A. franciscus is most similar to those tadpoles having submarginal papillae (i.e., Atelopus balios, Atelopus flavescens, Atelopus nanay, Atelopus tricolor). The tadpole of A. franciscus shares several similarities with the larva of A. flavescens from French Guyana but differs from it by being smaller in size and in certain measurement. The phylogenetic relevance of tadpole characters in Atelopus is discussed, including body proportions, submarginal papillae, length of upper beak.

Abstract: We report on our experiences with the captive management and ex situ reproduction of the Harlequin toad from Suriname (Atelopus flavescens ) at the amphibian breeding unit of the Cologne Zoo. Egg deposition was stimulated by maintaining A. flavescens in a drier environment followed by a period of intensive irrigation. Here we provide for the first time an overview of the larval development from oviposition to metamorphosis, including diagnostic morphological char- acters according to Gosner. Eggs were arranged in strings and attached to the substrate below the water surface. Larvae hatched about five days after egg deposition and the characteristic abdomi- nal suctorial disc developed about two days later (stages 20-21). Tadpoles are gastromyzophorous and were observed rasping algae. The average time for larval development to stage 41 was 100-130 days. Larval development appears to be dependent on water temperature with faster development at higher temperatures. Concerning color pattern in adults, we observed a slight sexual dimorphism and we were able to recognize individuals due to a constant color pattern. However, color was ob- served to slightly change over time.