| alkaloids in madagascan frogs (mantella): pumiliotoxins, indolizidines, quinolizidines, and pyrrolizidines. | brightly colored ranid frogs of the genus mantella are found only in rain forests of madagascar. gc-ms and gc-ft-ir analyses of skin alkaloids of seven different species, including four populations of mantella madagascariensis, are reported. all contain one or more representatives of the pumiliotoxin a (ptx-a) class with the 13,14-dihydro derivatives 309a and 325a found in major amounts in the four populations of m. madagascariensis, while 307a (ptx-a) is found in two populations of m. madagasca ... | 1993 | 8377013 |
| quantifying the relationship between optical anatomy and retinal physiological sensitivity: a comparative approach. | light intensity varies 1 million-fold between night and day, driving the evolution of eye morphology and retinal physiology. despite extensive research across taxa showing anatomical adaptations to light niches, surprisingly few empirical studies have quantified the relationship between such traits and the physiological sensitivity to light. in this study, we employ a comparative approach in frogs to determine the physiological sensitivity of eyes in two nocturnal (rana pipiens, hyla cinerea) an ... | 2018 | 30198557 |