Gonatodes

Abstract: Two sphaerodactyline geckos, Gonatodes hasemani and G. humeralis were studied in eastern Rondonia, Brazil, to determine ecological factors allowing coexistence. Gonatodes hasemani lives primarily on fallen logs in undisturbed forest, whereas G. humeralis lives primarily on tree trunks. Although both species occur in most forest patches, G. hasemani is more common within terra firme (never flooded) forest, and G. humeralis is more common in forest adjacent to rivers. Gonatodes hasemani is slightly larger in body size and is more robust than the more arboreal G. humeralis. Both species are active at the same time during the day, maintain the same body temperatures, and are most frequently found in shade. Dietary overlaps based on numbers (0.831) and volumes (0.877) of prey types were high indicating relatively similar diets. Differences in prey types appear to reflect differences in microhabitat use, and both species eat prey of the same size. Reproductive characteristics are similar but the larger...

Abstract: Mitotic and meiotic chromosomes of the gekkonid lizard Gonatodes tanieae from Venezuela were analyzed with conventional staining, differential banding techniques, and in situ hybridization using a synthetic telomeric DNA probe. The karyotype of this species is distinguished by the extraordinarily reduced diploid chromosome number of 2n = 16, which is the lowest value known for reptiles. In contrast to most other reptilian species, G. taniae has exclusively bi-armed (meta- and submetacentric) macrochromosomes and no microchromosomes. Examination of the mitotic chromosomes with AT and GC base pair-specific fluorochromes shows the absence of multiple banding patterns in euchromatic regions. The n = 8 diakinetic bivalents of male meiosis present terminal, subterminal, interstitial, and pericentromeric chiasmata. Comparison of the karyotypes of G. taniae and G. vittatus (also collected in Venezuela), and with those of three other Gonatodes species, indicates that the exceptional diploid number of 2n = 16 is the result of repeated centric fusions. In addition to the telomeres, all pericentromeric regions of the G. taniae chromosomes contain considerable amounts of the (TTAGGG)n telomeric sequence. These are probably not only relics of the centric fusions, but also a major component of the highly repetitive DNA in the C band-positive heterochromatin.

Abstract: Sarisarinama is a pink sandstone plateau with a total area (summit and slope) of 832 km 2 located about 600 km SE of Caracas, in Estado Bolivar, Venezuela. It includes diverse environments along an elevational gradient from 400 m up to an elevation of 2100 m at its western cliffs. Sarisarinama is well known among spelunkers for its sinkholes (simas), among which Sima Mayor is the largest on earth. Herpetofaunal surveys at four camps in the uplands and two at the base of the massif revealed 32 species, four of which are here described as new taxa. These include three frogs in the genera Hyalinobatrachium, Anomaloglossus, and Pristimantis, and one gecko (genus Gonatodes). In addition to these new species, we name a fifth based on evidence that populations hitherto known as Hypsiboas benitezi from east of the Maigualida-Parima Mountains, including our Sarisarinama sample, are distinct species. Our sample of Stefania riae contained individuals with four different color patterns. Two aquatic species of lizards, Neusticurus racenisi and N. tatei, were found to occur microsympatrically and we provide a diagnosis for the poorly known N. tatei. Norops ortonii is reported for the second time from Venezuela. Dendrobates leucomelas was abundant in lowland areas around the massif. The significance of this frog for the indigenous Ye'kwana is commented upon, including its iconographic importance in basket weaving. We also include data on three other species of interest collected at Sarisarinama by a 1988 expedition from Simon Bolivar University and Radio Caracas Television. Throughout, we reference common names for most species in the indigenous Ye'kwana language, and we provide information on local legends and cultural anecdotes involving some of the local species. We comment on the zoogeography of the Sarisarinama herpetofauna by comparing it with that of other known tepuis.