12/3/2023 0 Comments Fernandina island racer snakesvenustissimus Eibl-Eibesfeldt, 1956 – Española Island and adjacent tiny Gardener Island sielmanni Eibl-Eibesfeldt, 1962 – Pinta Island mertensi Eibl-Eibesfeldt, 1962 – San Cristóbal and Santiago Islands hassi Eibl-Eibesfeldt, 1962 – Santa Cruz Island ater Gray, 1831 (not always recognized) – Pinzón Island albemarlensis Eibl-Eibesfeldt, 1962 – Isabela Island Seven or eight subspecies of the marine iguana, listed alphabetically, have traditionally been recognized: There is one confirmed record of a marine iguana outside the Galápagos Islands in 2014 an individual appeared on Isla de la Plata near the Ecuadorian mainland. On occasion one makes it to another island than its home island, resulting in hybridization between different marine iguana populations. However, even the oldest divergence between marine iguana populations is quite recent no more than 230,000 years and likely less than 50,000 years. These can be further divided, each subclade generally matching marine iguanas from one or two primary island, except on San Cristóbal where there are two subclades (a northeastern and a southwestern). The different marine iguana populations fall into three main clades: western islands, northeastern islands and southeastern islands. The hybrids have intermediate features, stay on land and are infertile. This is very rare and has only been documented a few times on South Plaza, a tiny island where the usually separated breeding territories and seasons of the two species overlap. They have been known to hybridize where their ranges overlap, resulting in the so-called hybrid iguana. The marine iguana and Galápagos land iguana remain mutually fertile in spite of being separated by millions of years and assigned to distinct genera. However, a more recent study that included both mtDNA and nDNA indicates that the two split about 4.5 million years ago, which is near the age of the oldest extant Galápagos islands ( Española and San Cristóbal). It has therefore traditionally been thought that the ancestral species inhabited parts of the volcanic archipelago that are now submerged. Based on a study that relied on mtDNA, the marine iguana was estimated to have diverged from land iguanas some 8–10 million years ago, which is older than any of the extant Galápagos islands. The land and marine iguanas of the Galápagos form a clade, the nearest relatives of which are the Ctenosaura iguanas of Mexico and Central America. Researchers theorize that land iguanas (genus Conolophus) and marine iguanas evolved from a common ancestor since arriving on the islands from Central or South America, presumably by rafting. Evolution A hybrid iguana, the result of interbreeding between a marine iguana and a Galápagos land iguana Its specific name is the Latin word cristatus meaning "crested," and refers to the low crest of spines along the animal's back.Īmblyrhynchus is a monotypic genus, having only one species, Amblyrhynchus cristatus. Its generic name, Amblyrhynchus, is a combination of two Greek words, Ambly- from Amblus (ἀμβλυ) meaning "blunt" and rhynchus (ρυγχος) meaning "snout". He recognized several of its distinctive features, but believed that the specimen he had received was from Mexico, a locality now known to be erroneous. The marine iguana was first described in 1825 as Amblyrhynchus cristatus by Thomas Bell. Taxonomy and evolution Species description and etymology Although relatively large numbers remain and it is locally abundant, this protected species is considered threatened, primarily from El Niño cycles, introduced predators and chance events like oil spills. Marine iguanas vary in appearance between the different islands and several subspecies are recognized. After mating, the female digs a nest hole in the soil where she lays her eggs, leaving them to hatch on their own a few months later. Large males defend territories for a short period, but smaller males have other breeding strategies. They mainly live in colonies on rocky shores where they bask after visiting the relatively cold water or intertidal zone, but can also be seen in marshes, mangrove swamps and beaches. Large males are able to dive to find this food source, while females and smaller males feed during low tide in the intertidal zone. Marine iguanas are the only extant lizard that spends time in a marine environment. Unique among modern lizards, it is a marine reptile that has the ability to forage in the sea for algae, which makes up almost all of its diet. The marine iguana ( Amblyrhynchus cristatus), also known as the sea iguana, saltwater iguana, or Galápagos marine iguana, is a species of iguana found only on the Galápagos Islands ( Ecuador).
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