Distribution: Ecuador (Galapagos Islands: Isla Isabela)
Type locality: approximately four km north of the Equator on the top of Volcan Wolf, Isla Isabela, Galápagos National Park, Ecuador (0.03792° N; 91.36324°W, datum WGS84, as recorded by a Garmin 12CX handheld GPS).
Habitat and Ecology
Basic reproductive biology of this iguana is unknown. In late spring 2010, a few C. marthae females were observed carrying 4-7 eggs in their follicles, investigated by a portable ultrasound machine (G. Gentile pers. comm. 2011). These data would indicate a much smaller clutch size than for the geographically closest population of C. subcristatus on Fernandina Island (7-23 eggs, Werner 1982). It is still unclear whether C. marthae and C. subcristatus have overlapping reproductive seasons and if the two species may compete for nesting sites on VolcÃ¡n Wolf; the location of these nests is unknown.
Average snout-to-vent length (SVL) of animals observed is 46.8 cm, males being significantly larger than females. The SVL of the smallest male GalÃ¡pagos Pink Land Iguana captured was 37.3 cm, a size that broadly corresponds to the SVL in seven-year old GalÃ¡pagos Land Iguana individuals (37.5 cm Â± 6.0 SD) from Santa Cruz, and even older individuals from Plaza Sur.
IUCN Red List Assessment
Red List Category
Red List Criteria
A single wild population of GalÃ¡pagos Pink Land Iguana exists and it is not found ex situ. Recently, the effective population size (Ne) has been estimated as large as 41.21 individuals (95% CL = 30.71-67.97) by using microsatellite data (9 loci) (Fulvo 2010). Mark-recapture data, by applying the Lincoln-Petersen method from two contiguous temporal samples in 2009 and 2010 (percentage of recapture = 53%), would indicate 192 adult individuals (95% CL = 155-260). Sex ratio estimated from samples collected in May 2009 was one male to 0.59 females and one male to 0.51 females in July 2010 (Gentile and Fulvo 2011).Past and future population trends are impossible to assess due to the lack of a sufficiently long series of estimates of population size. Monomorphism for a single mitochondrial DNA haplotype in a sample of 102 iguanas strongly suggests that the GalÃ¡pagos Pink Land Iguana might have suffered severe demographic contractions in the past (G. Gentile pers. comm. 2011). From 2005 to 2011, 133 adult individuals were captured and permanently marked with brands and Passive Integrated Transponders, representing nearly all observed Pink Iguanas (G. Gentile pers. comm. 2011). During these surveys, no juveniles were observed, suggesting population recruitment appears to be non-effective.
The population of GalÃ¡pagos Pink Land Iguana is extremely small and prone to both demographic and genetic stochasticity, as well as environmental stochasticity (volcanic eruptions, droughts).
Because of the overlapping range with GalÃ¡pagos Land Iguana, hybridization may occur, generating introgression between C. marthae and C. subcristatus on VolcÃ¡n Wolf. Although there is no evidence of living F1 hybrids at present, DNA evidence shows that rare events of hybridization have occurred, though the severity of subsequent introgression has not been fully evaluated yet (Gentile et al. 2009, Fulvo 2010). Because the population is so small, rare events of hybridization may have a significant effect on the species.
In addition to the GalÃ¡pagos Hawk (Buteo galapagoensis), the only native predator of GalÃ¡pagos Pink Land Iguanas on VolcÃ¡n Wolf, invasive alien Black Rats (Rattus rattus) and feral cats (Felis catus) are potential predators of eggs and hatchlings. It is known that feral cats prey on GalÃ¡pagos Land Iguanas up to three and four years old. Animals in this age class represent a size that has not been found among Pink Iguanas. Therefore, it is suspected that feral cats pose a significant threat to population recruitment in GalÃ¡pagos Pink Land Iguanas.
VolcÃ¡n Wolf is an active volcano, with several eruptions recorded in the last century, most recently in 1982. Most recent lava is found on the eastern and southern sides of the volcano and in the caldera (Geist et al. 2005). Eruptions may have caused local extinctions of populations of C. subcristatus in the past, for example, VolcÃ¡n Chico (on the eastern side of VolcÃ¡n Sierra Negra) in 1979 (Snell et al. 1984).
Droughts may be severe on the top of VolcÃ¡n Wolf. Although adults are expected to cope fairly well with drought since they obtain water from consumed plants, the resultant scarcity of food may potentially cause aborted reproduction for the year due to a combination of lack of egg laying, a higher number of infertile eggs laid, and poor juvenile survival.
Ectoparasite load is high in both GalÃ¡pagos Land Iguanas and Pink Iguanas on VolcÃ¡n Wolf. In fact, the location is characterized by a massive occurrence of ticks, which are much more abundant in VolcÃ¡n Wolf than elsewhere in the archipelago. Both C. marthae and the C. subcristatus populations from VolcÃ¡n Wolf show an unbalanced leukocyte formula compared to other populations of land iguanas from the whole archipelago. This could be related to the presence of ticks, but could also indicate a possible endoparasitic infection affecting most individuals (Fulvo 2010). This issue and how it might effect the fitness of the two populations is under investigation.
There is no current or known historic human use or trade of this species.
All species of GalÃ¡pagos Land Iguanas (Conolophus spp.) are included in Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). The known geographic range of GalÃ¡pagos Pink Land Iguana is within the GalÃ¡pagos National Park, the legal authority governing and protecting biological diversity of the GalÃ¡pagos Islands. The Land Iguanas are included in the Management of Native and Endemic Species Program, as part of the Management Plan of the GalÃ¡pagos National Park.The GalÃ¡pagos National Park undertakes major campaigns to control and eradicate invasive alien species in the GalÃ¡pagos, including on VolcÃ¡n Wolf. Such actions have so far successfully prevented habitat disturbance by feral goats in northern Isabela and promoted habitat restoration of southern Isabela. In the early 2000s, a three-year programme to eradicate feral cats from the island of Baltra (where C. subcristatus was repatriated from 1991 onwards) was effective by initially poisoning with sodium monofluoroacetate (compound 1080), then trapping or shooting the remaining cats (Phillips et al. 2005). However, the applicability of this protocol on VolcÃ¡n Wolf is questionable due to the difficult terrain and is likely impossible for an island as large as Isla Isabela, an area of 4,588 kmÂ² (Nogales et al. 2004). Further evaluation of the feral cat population on VolcÃ¡n Wolf is needed for the purpose of implementing a programme for their control.
Based on successful programmes for the populations of C. subcristatus from BahÃa Cartago (Isabela), Santa Cruz, and Baltra islands (Snell et al. 1984), the National Park is also considering a captive-breeding programme for C. marthae. The University Tor Vergata (Rome, Italy) is actively assisting the Park in this regard.
The GalÃ¡pagos Pink Land Iguana is not in contact with humans in GalÃ¡pagos except for the purpose of scientific investigation and management. The GalÃ¡pagos National Park does not envision a plan to include VolcÃ¡n Wolf in the list of touristic sites nor other possible intrusions to the population. Nevertheless, as the species is endemic and has a very limited distribution, the National Park has added a specific educational module focused on this species in the courses aimed at training and updating nature guides. This training ensures proper information is conveyed to visiting tourists.
Information on the population biology and ecology of Pink Iguanas is very limited and research has begun. Research needs include monitoring of population and habitat trends, diet analysis, and in-depth study of the reproductive biology of this species. Clarifying the frequency of hybridization and level of genetic introgression between C. marthae and C. subcristatus is urgently needed. Additionally, the health status of the population should be monitored and the possible impact of a high parasite load on the fitness of the population should be investigated.
Additionally, in the event a captive breeding programme is started, the GalÃ¡pagos National Park, in collaboration with the University Tor Vergata, will develop an education programme for local people and tourists. It is extremely difficult and expensive to access the study area. The need to transport equipment to and from the site limits the duration of research trips and consequently the extent of research that can be conducted on any one trip. The construction of a small low-impact, temporary field structure near the top of volcano would greatly help by allowing longer field trips and more effective research work and monitoring.
Galápagos Pink Land Iguana
The Galápagos Pink Land Iguana (Conolophus marthae) is a species of lizard of the Iguanidae family. It is native only to northern Isabela Island of the Galápagos. The iguana has a pink body with some stripes, prompting some to call it a "pink iguana" or the "Galapagos rosy iguana." The species was first discovered in 1986 and was identified as a separate species, distinct from the Galapagos land iguana, early in 2009. 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.
Taxonomy and etymology[edit source | edit]
Its generic name, Conolophus, is derived from two Greek words: conos (κώνος) meaning "spiny" and lophos (λοφος) meaning "crest" or "plume," denoting the spiny crests along their backs. Its tentative specific name rosada was derived from the Spanish word meaning "pink" in reference to the animal's pinkish body color. The term was later abandoned for the formal description and the species epithet, marthae, was chosen in memory of Martha Rebecca Gentile, the stillborn daughter of the describer Gabriele Gentile.
The species was first formally described in early 2009 as being distinct from the other island iguana populations. Genetic analysis of the pink morph subpopulation resulted in an identification of a genetically distinct and isolated population totally different from the other iguana species on the island. Further analysis suggested that this particular species diverged from its ancestral stock some 5.7 million years past.
Anatomy[edit source | edit]
Conolophus marthae is anatomically similar to the closely related species, Conolophus subcristatus. Both exemplify the typical saurian body shape, having squat, quadrupedal bodies with elongated tails. The legs sprawl out to the sides like all lizards, and a row of short spines runs down the middle of the lizard's back starting from the base of the neck to the tail. However, there are a few anatomical differences between the two species. The crest of C. marthae has been described as somewhat different from that of C. subcristatus. The most apparent difference is that of coloration – the body of C. marthae is pinkish with a few wide, vertical dark bands. This is a stark contrast from the yellow-brown coloration of C. subcristatus.
Part of the Galapagos land iguana clade, individuals of the species first came into the public light in 1986 when park rangers spotted some pink lizards on a local volcano on Isabela Island. The entire range of the species is limited to Volcano Wolf on that particular island, and nowhere else in the Galapagos archipelago. No more than a hundred individuals have been estimated to form the single population of C. marthae. Although a formal review has not been performed on the population's status, it has been suggested it should be considered a critically endangered species.
References[edit source | edit]
- Gentile, Gabriele; Snell, Howard L. (2009). "Conolophus marthae sp.nov. (Squamata, Iguanidae), a new species of land iguana from the Galápagos archipelago". Zootaxa 2201: 1–10.
- Gentile, G. (2012). "Conolophus marthae". IUCN Red List of Threatened Species. Version 2012.1. International Union for Conservation of Nature. Retrieved 21 August 2012.
- "New Galapagos species identified". Scientific American. 2009-01-07. Retrieved 2009-01-07.
- Gentile, Gabriele; Anna Fabiani, Cruz Marquez, Howard L. Snell, Heidi M. Snell, Washington Tapia, and Valerio Sbordonia (2009). "An overlooked pink species of land iguana in the Galapagos". Proceedings of the National Academy of Sciences of the United States of America (National Academy of Sciences of the United States of America) 106 (2): 507–11. doi:10.1073/pnas.0806339106. PMC 2626733. PMID 19124773.
- Black, Richard (2009-01-07). "Pink iguana rewrites family tree". BBC News (BBC). Retrieved 2009-01-07.
- Madrigal, Alexis (2009-01-05). "Pink Iguana That Darwin Missed Holds Evolutionary Surprise". Wired Science. Wired. Retrieved 2009-01-06.