Variation among populations of Galapagos land iguanas (Conolophus): contrasts of phylogeny and ecology
HOWARD L. SNELL,HEIDI M. SNELL,†C. RICHARD TRACY,
Article first published online: 28 JUN 2008
A phylogenetic scheme derived via multivariate analyses of adaptively neutral scale characteristics is compared to patterns of ecological adaptation in body size and shape, hatchling size, clutch size, and reproductive seasonality, in extant populations of Galapagos land iguanas (genus Conolophus). Three groups of land iguana populations are identified, the oldest being the population of Isla Santa Fe, followed by the populations of the central islands (Santa Cruz, Plaza Sur and Baltra), the youngest populations are those of the western islands (Fernandina and Isabela). Patterns of ecological similarity among these populations are not concordant with phylogenetic lineage. Populations most similar in ecological characteristics are often phylogenetically divergent. Adaptation to local conditions by iguana populations is apparently more important than phylogenetic constraint in explaining variation in ecological characteristics. The assumption that phylogenetically closely-related organisms are also ecologically more similar than less closely-related organisms is not supported by this evidence. Some previous studies may have been misled by using ecological characteristics to derive phylogenetic lineages, resulting in circular support of the assumption.
Pink Iguana found on Isabella Island (1986)- 3rd type of Land Iguana
Conolophus rosada description
It can reach more than a meter long (over 3 feet) and weights up to 12 kilograms (24 pounds).
Even though, Conolophus rosada shares some physical characteristics with the other land iguana Conolophus subcristatus, it shows different courtship and territorial displays.
They also found that in addition to its striking coloring, the pink iguana differs from most other iguanas with its flat dorsal head scales and striking differences with regard to technique in the oh-so-important head-bobbing behavior used in marking territory and courtship.
An overlooked pink species of land iguana in the Galápagos
Gabriele Gentilea,Anna Fabiania,Cruz Marquezb,Howard L. Snellc,Heidi M. Snellc,Washington Tapiad, Valerio Sbordonia+ Author Affiliations
Abstract Despite the attention given to them, the Galápagos have not yet finished offering evolutionary novelties. When Darwin visited the Galápagos, he observed both marine (Amblyrhynchus) and land (Conolophus) iguanas but did not encounter a rare pink black-striped land iguana (herein referred to as “rosada,” meaning “pink” in Spanish), which, surprisingly, remained unseen until 1986. Here, we show that substantial genetic isolation exists between the rosada and syntopic yellow forms and that the rosada is basal to extant taxonomically recognized Galápagos land iguanas. The rosada, whose present distribution is a conundrum, is a relict lineage whose origin dates back to a period when at least some of the present-day islands had not yet formed. So far, this species is the only evidence of ancient diversification along the Galápagos land iguana lineage and documents one of the oldest events of divergence ever recorded in the Galápagos. Conservation efforts are needed to prevent this form, identified by us as a good species, from extinction.
What does pink iguana eat?
A follow-up expedition to Wolf Volcano on Isabela Island was recently completed, and 101 pink iguanas were found, marked, and sampled. A team of scientists and technicians from the Galapagos National Park Service (GNPS) and the University Tor Vergata of Rome (UTV) returned last night from an expedition to Wolf Volcano, where they collected information about the newly discovered pink iguana species.
During the expedition, team members located, marked, and took blood samples from 101 adult pink iguanas, 55 of which were male and 46 female. They observed one recently hatched iguana, but were unable to capture it. Although no nests were found, the team did find reproductively active iguanas.
The team was able to delineate the habitat range of this species, confirming that they share the same area with the yellow land iguana (Conolophus subcristatus), exclusively on Wolf Volcano. Pink iguanas have not been found on either of the adjacent volcanoes, Darwin and Ecuador.
According to Washington Tapia, the GNPS project leader, “The fact that 101 pink iguanas were found suggests that this population is not as threatened as previously feared. This gives us time to complete the genetic analyses of the blood samples and evaluate other data to determine if any management measures are necessary for its conservation.”
Additionally, the team collected samples of approximately 30 plant species, which are potential items in the pink iguana’s diet. Molecular analysis of these samples in comparison with iguana scat samples collected will determine with certainty what these iguanas eat.
The GNPS and the UTV will continue to analyze the data and samples collected on this trip in order to more fully understand the natural history of this new species.
The pink iguana was first sighted during field work on Wolf Volcano in 1986. Initially it was thought that these were yellow iguanas with unusual blotches. However, subsequent genetic analyses revealed that these were, in fact, a new species.