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Paradiso C, Gratton P, Trucchi E, López-Delgado J, Gargano M, Garizio L, Carr IM, Colosimo G, Sevilla C, Welch ME, Firdaus-Raih M, Noor Mat-Isa M, Goodman SJ, Gentile G. Genomic insights into the biogeography and evolution of Galápagos iguanas. Mol Phylogenet Evol 2025; 204:108294. [PMID: 39880223 DOI: 10.1016/j.ympev.2025.108294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2024] [Revised: 01/15/2025] [Accepted: 01/22/2025] [Indexed: 01/31/2025]
Abstract
Galápagos iguanas are a monophyletic group endemic to the Galápagos archipelago, comprising the marine iguana Amblyrhynchus cristatus and three species of land iguanas: Conolophus subcristatus, C. pallidus and C. marthae. The biogeographic history of the land species in relation to their current distributions remains uncertain, in particular the origins of C. marthae, which is restricted to a small area of the northern part of Isabela Island. The classification of C. pallidus as a separate species has also been debated. We analyzed DNA sequences (RADseq) to reconstruct demographic histories of selected local populations of all Galápagos iguana species and estimate their divergence times within a multispecies coalescent framework. Our results indicate an early date for the colonization of Galápagos by iguanas, relative to island formation, at ca. 10 Mya, and support a recent split of C. marthae via allopatric speciation, after the emergence of Isabela Island, at ca. 0.57 Mya. We find contrasting demographic histories in C. marthae and the syntopic population of C. subcristatus, suggesting competitive interaction between these species. We also confirm that the divergence of C. pallidus from C. subcristatus is recent (0.09 Mya) and close in time to the split between populations of C. subcristatus from different islands. Our genetic data support recent census estimates indicating a relatively small current effective population size (Ne) in all the studied populations. Our findings shed light on the evolutionary history of Galápagos iguanas and emphasize the need for targeted conservation strategies.
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Affiliation(s)
- Cecilia Paradiso
- PhD Program in Evolutionary Biology and Ecology, Department of Biology, University of Rome TorVergata, 00133 Rome, Italy.
| | - Paolo Gratton
- Department of Biology, Università degli Studi di Roma Tor Vergata, Italy
| | | | - Julia López-Delgado
- School of Biology, Faculty of Biological Sciences, University of Leeds, United Kingdom
| | | | - Lorenzo Garizio
- PhD Program in Evolutionary Biology and Ecology, Department of Biology, University of Rome TorVergata, 00133 Rome, Italy
| | - Ian M Carr
- Leeds Institute for Molecular Medicine, University of Leeds, United Kingdom
| | - Giuliano Colosimo
- Department of Biology, Università degli Studi di Roma Tor Vergata, Italy
| | | | - Mark E Welch
- Department of Biological Sciences, Mississippi State University, Starkville, MS, USA
| | | | - Mohd Noor Mat-Isa
- Malaysia Genome and Vaccine Institute, National Institutes of Biotechnology Malaysia, Malaysia
| | - Simon J Goodman
- School of Biology, Faculty of Biological Sciences, University of Leeds, United Kingdom
| | - Gabriele Gentile
- Department of Biology, Università degli Studi di Roma Tor Vergata, Italy.
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Colosimo G, Gargano M, Loreti P, Bracciale L, De Luca M, Catini A, Di Natale C, Vera C, Sevilla CR, Gerber GP, Gentile G. Remote tracking of Galápagos pink land iguana reveals large elevational shifts in habitat use. J Nat Conserv 2022. [DOI: 10.1016/j.jnc.2022.126210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Di Giacomo C, Pucillo L, Sevilla C, Fucci G, Massoud R, Bernardini S, Fraziano M, Gentile G. 25-Hydroxyvitamin D Plasma Levels in Natural Populations of Pigmented and Partially Pigmented Land Iguanas from Galápagos ( Conolophus spp.). BIOMED RESEARCH INTERNATIONAL 2022; 2022:7741397. [PMID: 35872852 PMCID: PMC9303120 DOI: 10.1155/2022/7741397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 06/25/2022] [Indexed: 11/17/2022]
Abstract
We report the first data on 25-hydroxyvitamin D plasma levels in natural populations of three species of land iguana endemic to the Galápagos Islands (Conolophus marthae, C. subcristatus, and C. pallidus). The pigment is present throughout the whole body in the skin of C. subcristatus and C. pallidus. On the contrary, pigment is not present in the skin of an extended part of the body in C. marthae. The only existing population of C. marthae is syntopic with a population of C. subcristatus, and the two species are closely related. These circumstances would suggest that, under the assumption that the species show a similar basking behavior and in the absence of compensatory mechanisms, lighter pigmentation should favor higher vitamin D levels. Thus, C. marthae, compared with C. subcristatus in Wolf Volcano, could show higher levels of 25(OH)D plasma levels, or equal, if compensatory mechanisms exist. The three species showed levels in the range of average values for healthy iguanas. However, contrary to the expectation, C. marthae consistently exhibited the lowest 25(OH)D plasma levels. We discuss possible factors affecting vitamin concentration and hypothesize that C. marthae may use the habitat to limit exposure to the high UVB irradiation at Wolf Volcano.
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Affiliation(s)
- Cristina Di Giacomo
- Clinical Biochemistry and Pharmacology Laboratory, National Institute for Infectious Diseases “L. Spallanzani”, Rome, Italy
- Clinical Pathology Laboratory, A.O. San Camillo-Forlanini, Rome, Italy
| | - Leopoldo Pucillo
- Clinical Biochemistry and Pharmacology Laboratory, National Institute for Infectious Diseases “L. Spallanzani”, Rome, Italy
- Clinical Pathology Laboratory, A.O. San Camillo-Forlanini, Rome, Italy
| | - Christian Sevilla
- Galápagos National Park Directorate, Puerto Ayora, Galápagos, Ecuador
| | - Giorgio Fucci
- Department of Experimental Medicine, University Tor Vergata, Rome, Italy
| | - Renato Massoud
- Department of Experimental Medicine, University Tor Vergata, Rome, Italy
| | - Sergio Bernardini
- Department of Experimental Medicine, University Tor Vergata, Rome, Italy
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Conservation of a flagship species: Health assessment of the pink land iguana, Conolophus marthae. PLoS One 2022; 17:e0257179. [PMID: 35349571 PMCID: PMC8963547 DOI: 10.1371/journal.pone.0257179] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Accepted: 02/21/2022] [Indexed: 11/19/2022] Open
Abstract
The pink land iguana, Conolophus marthae, is one of four species of iguanas (three terrestrial and one marine) in the Galápagos Islands, and the only one listed as critically endangered by the IUCN. The species can only be found on the north-west slopes of the highest volcano on Isabela Island and was first described to science in 2009. As part of a population telemetry study, a health assessment was authorized by the Galápagos National Park. Wild adult iguanas were captured on Wolf Volcano in September 2019 and April 2021 to record morphological and physiological parameters including body temperature, heart rate, intraocular pressures, tear formation, and infrared iris images. Blood samples were also collected and analyzed. An i-STAT portable blood analyzer was used to obtain values for base excess in the extracellular fluid compartment (BEecf), glucose (Glu), hematocrit (HctPCV), hemoglobin (Hb), ionized calcium (iCa), partial pressure of carbon dioxide (pCO2), partial pressure of oxygen (pO2), percent oxygen saturation (sO2%), pH, potassium (K), and sodium (Na). When possible, data were compared to previously published and available data for the other Galápagos iguanas. The results reported here provide baseline values that will be useful in detecting changes in health status among pink land iguanas affected by climate change, invasive species, anthropogenic threats, or natural disturbances. The collected data also provide an invaluable resource for conservation scientists planning to implement conservation strategies, like translocations, that may temporarily alter these baseline values.
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Colosimo G, Di Marco G, D'Agostino A, Gismondi A, Vera CA, Gerber GP, Scardi M, Canini A, Gentile G. Chemical signatures of femoral pore secretions in two syntopic but reproductively isolated species of Galápagos land iguanas (Conolophus marthae and C. subcristatus). Sci Rep 2020; 10:14314. [PMID: 32868803 PMCID: PMC7458923 DOI: 10.1038/s41598-020-71176-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 08/03/2020] [Indexed: 11/09/2022] Open
Abstract
The only known population of Conolophus marthae (Reptilia, Iguanidae) and a population of C. subcristatus are syntopic on Wolf Volcano (Isabela Island, Galápagos). No gene flow occurs suggesting that effective reproductive isolating mechanisms exist between these two species. Chemical signature of femoral pore secretions is important for intra- and inter-specific chemical communication in squamates. As a first step towards testing the hypothesis that chemical signals could mediate reproductive isolation between C. marthae and C. subcristatus, we compared the chemical profiles of femoral gland exudate from adults caught on Wolf Volcano. We compared data from three different years and focused on two years in particular when femoral gland exudate was collected from adults during the reproductive season. Samples were processed using Gas Chromatography coupled with Mass Spectrometry (GC–MS). We identified over 100 different chemical compounds. Non-Metric Multidimensional Scaling (nMDS) was used to graphically represent the similarity among individuals based on their chemical profiles. Results from non-parametric statistical tests indicate that the separation between the two species is significant, suggesting that the chemical profile signatures of the two species may help prevent hybridization between C. marthae and C. subcristatus. Further investigation is needed to better resolve environmental influence and temporal reproductive patterns in determining the variation of biochemical profiles in both species.
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Affiliation(s)
- Giuliano Colosimo
- Institute for Conservation Research, San Diego Zoo Global, 15600 San Pasqual Valley Road, Escondido, CA, 92027-7000, USA.,Department of Biology, University of Rome Tor Vergata, Via della Ricerca Scientifica, 00133, Rome, Italy
| | - Gabriele Di Marco
- Department of Biology, University of Rome Tor Vergata, Via della Ricerca Scientifica, 00133, Rome, Italy
| | - Alessia D'Agostino
- Department of Biology, University of Rome Tor Vergata, Via della Ricerca Scientifica, 00133, Rome, Italy
| | - Angelo Gismondi
- Department of Biology, University of Rome Tor Vergata, Via della Ricerca Scientifica, 00133, Rome, Italy
| | - Carlos A Vera
- Galápagos National Park Directorate, Technical Biodiversity Research, Av. C. Darwin, Puerto Ayora, 200350, Isla Santa Cruz, Galápagos, Ecuador
| | - Glenn P Gerber
- Institute for Conservation Research, San Diego Zoo Global, 15600 San Pasqual Valley Road, Escondido, CA, 92027-7000, USA
| | - Michele Scardi
- Department of Biology, University of Rome Tor Vergata, Via della Ricerca Scientifica, 00133, Rome, Italy
| | - Antonella Canini
- Department of Biology, University of Rome Tor Vergata, Via della Ricerca Scientifica, 00133, Rome, Italy
| | - Gabriele Gentile
- Department of Biology, University of Rome Tor Vergata, Via della Ricerca Scientifica, 00133, Rome, Italy.
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Hedrick PW. Galapagos Islands Endemic Vertebrates: A Population Genetics Perspective. J Hered 2020; 110:137-157. [PMID: 30541084 DOI: 10.1093/jhered/esy066] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/10/2018] [Indexed: 11/12/2022] Open
Abstract
The organisms of the Galapagos Islands played a central role in the development of the theory of evolution by Charles Darwin. Examination of the population genetics factors of many of these organisms with modern molecular methods has expanded our understanding of their evolution. Here, I provide a perspective on how selection, gene flow, genetic drift, mutation, and inbreeding have contributed to the evolution of 6 iconic Galapagos species: flightless cormorant, pink iguana, marine iguana, Galapagos hawk, giant tortoises, and Darwin's finches. Because of the inherent biological differences among these species that have colonized the Galapagos, different population genetic factors appear to be more or less important in these different species. For example, the Galapagos provided novel environments in which strong selection took place and the Darwin's finches diversified to produce new species and the cormorant adapted to the nutrient-rich western shores of the Galapagos by losing its ability to fly and genomic data have now identified candidate genes. In both the pink iguana, which exists in one small population, and the Galapagos hawk, which has small population sizes, genetic drift has been potentially quite important. There appears to be very limited interisland gene flow in the flightless cormorant and the Galapagos hawk. On the other hand, both the marine iguana and some of the Darwin's finches appear to have significant interisland gene flow. Hybridization between species and subspecies has also introduced new adaptive variation, and in some cases, hybridization might have resulted in despeciation. Overall, new population genetics and genomics research has provided additional insight into the evolution of vertebrate species in the Galapagos.
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