| the distribution of dopamine in the brain of a tortoise, geochelone chilensis (gray). | 1. dopamine was found in the tortoise brain; the highest concentration (3.7 mug/g) occurred in a region of the telencephalon containing the nucleus basalis and cortex olfactoria. this region may be considered similar to the mammalian and avian corpus striatum with respect to dopamine.2. the administration of reserpine or prenylamine substantially decreased the concentration of dopamine in the tortoise brain. this effect appeared later and lasted longer than in birds or mammals. when these drugs ... | 1969 | 5824650 |
| origin and evolutionary relationships of giant galápagos tortoises. | perhaps the most enduring debate in reptile systematics has involved the giant galápagos tortoises (geochelone nigra), whose origins and systematic relationships captivated charles darwin and remain unresolved to this day. here we report a phylogenetic reconstruction based on mitochondrial dna sequences from galápagos tortoises and geochelone from mainland south america and africa. the closest living relative to the galápagos tortoise is not among the larger-bodied tortoises of south america but ... | 1999 | 10557302 |
| the distal forelimb musculature in aquatic and terrestrial turtles: phylogeny or environmental constraints? | we compared the muscular anatomy of the distal front limb in terrestrial and aquatic chelonians to test whether observed differences between the two groups are associated with their divergent lifestyles and locomotor modes. given the different use of the forelimb in the two environments (body support and propulsion on land vs. mainly propulsion in water) we expected that: (1) aquatic and terrestrial turtles would show differences in their muscular anatomy, with aquatic species having more indivi ... | 2008 | 19172731 |
| reptile trade and the risk of exotic tick introductions into southern south american countries. | ticks exotic for the neotropical region were found on python regius imported into argentina and chile. all ticks (7 males and 3 females) were classified as amblyomma latum koch, 1844 ( = aponomma latum). additionally, four lots comprising 18 males of the argentinean tortoise tick, amblyomma argentinae neumann, 1904, were found on a terrestrial tortoise, chelonoidis chilensis, and on three terrestrial tortoises (probably c. chilensis) imported to uruguay presumably from argentina). these findings ... | 2005 | 15969465 |
| identification of limiting climatic and geographical variables for the distribution of the tortoise chelonoidis chilensis (testudinidae): a baseline for conservation actions. | background. just as for most other tortoise species, the once common chaco tortoise, chelonoidis chilensis (testudinidae), is under constant threat across it distribution in argentina, bolivia and paraguay. despite initial qualitative description of the species distribution and further individual reports of new locations for the species, there is no description of the species distribution in probabilistic terms. with this work we aim to produce an updated predictive distribution map for c. chile ... | 2015 | 26557430 |
| osteohistological correlates of muscular attachment in terrestrial and freshwater testudines. | sharpey's fibers are considered the anatomical structures integrated to the muscles. since these fibers leave marks at the microscopic level, their presence and distribution are used as evidence of muscle attachment in extinct and extant forms. in recent years, studies have been focusing on muscle-bone and tendon-bone interaction mostly on mammals. the main objective of this work is to contribute to the morphological and histological knowledge of muscle attachment in other amniotes, such as rept ... | 2019 | 30901084 |