variations in the off-axis refractive state in the eye of the vietnamese leaf turtle (geoemyda spengleri).lower-field myopia has been described for various vertebrates as an adaptation that permits the animal to keep the ground in focus during foraging, and, at the same time, to look out for distant objects, such as predators, in the upper visual field. off-axis measurements with infrared photoretinoscopy in the eye of geoemyda spengleri revealed a constant refractive state in the horizontal plane of the visual field but variable refraction in the vertical plane. in the three turtles investigated, t ...200414666375
accommodation behaviour during prey capture in the vietnamese leaf turtle ( geoemyda spengleri).vietnamese leaf turtles ( geoemyda spengleri) were tested for their ability to focus on prey objects at various distances. accommodation was continuously measured by infrared photoretinoscopy. all animals investigated during this study showed a surprisingly high precision of accommodation over a range of over 30 d. measured accommodation matched the target distance accurately for distances between 3 and 17 cm. the turtles switched between independent and coupled accommodation in the two eyes. in ...200414666374
turtles of the genera geoemyda and pangshura (testudines: geoemydidae) lack differentiated sex chromosomes: the end of a 40-year error cascade for pangshura.for a long time, turtles of the family geoemydidae have been considered exceptional because representatives of this family were thought to possess a wide variety of sex determination systems. in the present study, we cytogenetically studied geoemyda spengleri and g. japonica and re-examined the putative presence of sex chromosomes in pangshura smithii. karyotypes were examined by assessing the occurrence of constitutive heterochromatin, by comparative genome hybridization and in situ hybridizati ...201930755825
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