Ctenosaura hemilopha
Encyclopedia
Ctenosaura hemilopha, also known as the Cape Spinytail Iguana , is a species of spinytail iguana
endemic
to Baja California
. It is arboreal and primarily herbivorous, although it can be an opportunistic carnivore
. Males may grow up to 100 centimetres (39.4 in) in length, while females are smaller, with a length of up to 70 centimetres (27.6 in). There are five subspecies currently recognized.
The existence of mainland and insular populations of this species has been valuable in providing biologists with study and control groups comparing the evolution of island populations and their mainland counterparts. The San Esteban Island
subspecies (C.h. conspicuosa) coexists with the giant San Esteban Chuckwalla
, contrary to predictions of ecological niche
theory.
Edward Drinker Cope
in 1863. The generic
name, Ctenosaura
, is derived from two Greek
words: cteno (Κτενός), meaning "comb" (referring to the comblike spines on the lizard's back and tail), and saura (σαύρα), meaning "lizard". Its specific name is a combination of the Greek word hemisus (ήμισυς) meaning "half" and lophos (λοφος) meaning "crest" or "plume" ; both are in reference to the animal's short crest of spines, when compared to other species of its genus.
There are five subspecies
of C. hemilopha that are all similar in appearance and habitat.
theory, the species coexists with the giant San Esteban Chuckwalla
on San Esteban Island
. The two species forage for the same plants in the same habitat at the same time of day during the same season, with neither species displacing the other.
The Cape Spinytail iguana makes its den in old woodpecker
nests in giant columnar cacti, and in other tree cavities. The most important factors determining the choice of cactus are the existence of other holes, and the cactus height because these types of refuges allow the lizards to feed and bask on the tree, minimizing the risk of predation.
The existence of mainland and insular populations of this species has been valuable in providing biologists with study and control groups comparing the evolution
of island populations.
Males achieve a maximum length of 100 centimetres (39.4 in), while females are typically 30% smaller at 70 centimetres (27.6 in). Males develop large jowls and a dorsal crest made up of larger dorsal spines, making the animal sexually dimorphic
.
s, leaves, stems, fruit
, and cactus
such as the bushy Jatropha cuneata and the taller, spindly Solanum hindsianum. They will opportunistically eat smaller animals, eggs, and arthropod
s.
Ctenosaura
Ctenosaura is a genus of lizard commonly known as spinytail iguanas. The genus is part of the large lizard family, Iguanidae and is native to Mexico and Central America. The species range in size from about 5 inches to well over one meter. The distinctive feature of this genus is presence of the...
endemic
Endemic (ecology)
Endemism is the ecological state of being unique to a defined geographic location, such as an island, nation or other defined zone, or habitat type; organisms that are indigenous to a place are not endemic to it if they are also found elsewhere. For example, all species of lemur are endemic to the...
to Baja California
Baja California
Baja California officially Estado Libre y Soberano de Baja California is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is both the northernmost and westernmost state of Mexico. Before becoming a state in 1953, the area was known as the North...
. It is arboreal and primarily herbivorous, although it can be an opportunistic carnivore
Carnivore
A carnivore meaning 'meat eater' is an organism that derives its energy and nutrient requirements from a diet consisting mainly or exclusively of animal tissue, whether through predation or scavenging...
. Males may grow up to 100 centimetres (39.4 in) in length, while females are smaller, with a length of up to 70 centimetres (27.6 in). There are five subspecies currently recognized.
The existence of mainland and insular populations of this species has been valuable in providing biologists with study and control groups comparing the evolution of island populations and their mainland counterparts. The San Esteban Island
San Esteban Island
San Esteban Island is a small island in the Gulf of California, Mexico, located to the southwest of Tiburón Island. It is part of the Municipality of Hermosillo in Sonora, and has a land area of 39.773 km² , the 15th-largest island in Mexico. It is located in the Sea of Cortés...
subspecies (C.h. conspicuosa) coexists with the giant San Esteban Chuckwalla
San Esteban Chuckwalla
The San Esteban chuckwalla is a species of chuckwalla belonging to the Iguanidae family endemic to San Esteban Island in the Sea of Cortés...
, contrary to predictions of ecological niche
Ecological niche
In ecology, a niche is a term describing the relational position of a species or population in its ecosystem to each other; e.g. a dolphin could potentially be in another ecological niche from one that travels in a different pod if the members of these pods utilize significantly different food...
theory.
Taxonomy and etymology
Ctenosaura hemilopha was first described by zoologistZoology
Zoology |zoölogy]]), is the branch of biology that relates to the animal kingdom, including the structure, embryology, evolution, classification, habits, and distribution of all animals, both living and extinct...
Edward Drinker Cope
Edward Drinker Cope
Edward Drinker Cope was an American paleontologist and comparative anatomist, as well as a noted herpetologist and ichthyologist. Born to a wealthy Quaker family, Cope distinguished himself as a child prodigy interested in science; he published his first scientific paper at the age of nineteen...
in 1863. The generic
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
name, Ctenosaura
Ctenosaura
Ctenosaura is a genus of lizard commonly known as spinytail iguanas. The genus is part of the large lizard family, Iguanidae and is native to Mexico and Central America. The species range in size from about 5 inches to well over one meter. The distinctive feature of this genus is presence of the...
, is derived from two Greek
Ancient Greek
Ancient Greek is the stage of the Greek language in the periods spanning the times c. 9th–6th centuries BC, , c. 5th–4th centuries BC , and the c. 3rd century BC – 6th century AD of ancient Greece and the ancient world; being predated in the 2nd millennium BC by Mycenaean Greek...
words: cteno (Κτενός), meaning "comb" (referring to the comblike spines on the lizard's back and tail), and saura (σαύρα), meaning "lizard". Its specific name is a combination of the Greek word hemisus (ήμισυς) meaning "half" and lophos (λοφος) meaning "crest" or "plume" ; both are in reference to the animal's short crest of spines, when compared to other species of its genus.
There are five subspecies
Subspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
of C. hemilopha that are all similar in appearance and habitat.
- C. h. hemilopha occurs on the southern half of the Baja California peninsulaBaja California PeninsulaThe Baja California peninsula , is a peninsula in northwestern Mexico. Its land mass separates the Pacific Ocean from the Gulf of California. The Peninsula extends from Mexicali, Baja California in the north to Cabo San Lucas, Baja California Sur in the south.The total area of the Baja California...
, Mexico. - C. h. conspicuosa is found on San Esteban IslandSan Esteban IslandSan Esteban Island is a small island in the Gulf of California, Mexico, located to the southwest of Tiburón Island. It is part of the Municipality of Hermosillo in Sonora, and has a land area of 39.773 km² , the 15th-largest island in Mexico. It is located in the Sea of Cortés...
(Isla San Esteban) and Cholludo Island (Isla Cholludo) in the Gulf of CaliforniaGulf of CaliforniaThe Gulf of California is a body of water that separates the Baja California Peninsula from the Mexican mainland...
. - C. h. insulana is found on Cerralvo IslandCerralvo IslandJacques Cousteau Island is the official name recently applied to an uninhabited island, , located off the coast of the Cerralvo Channel near the city of La Paz in the Mexican state of Baja California Sur.It is eighteen miles long with a land area of 136.498 km² , and is the...
(Isla Cerralvo) 5 miles off the southern part of Baja near La Paz, Baja California SurLa Paz, Baja California SurLa Paz is the capital city of the Mexican state of Baja California Sur and an important regional commercial center. The city had a 2010 census population of 215,178 persons, but its metropolitan population is somewhat larger because of surrounding towns like el Centenario, el Zacatal and San Pedro...
. - C. h. macrolopha is found on the Mexican mainland from HermosilloHermosilloHermosillo is a city and municipality located centrally in the northwestern Mexican state of Sonora. It is the capital and main economic center for the state and region. It contains almost all of the state's manufacturing and has thirty percent of its population...
, SonoraSonoraSonora officially Estado Libre y Soberano de Sonora is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided into 72 municipalities; the capital city is Hermosillo....
, south to mid SinaloaSinaloaSinaloa officially Estado Libre y Soberano de Sinaloa is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided in 18 municipalities and its capital city is Culiacán Rosales....
. - C. h. nolascensis is found on San Pedro Nolasco Island (Isla San Pedro Nolasco).
Distribution and habitat
It is believed that these iguanas may have ended up on the Baja peninsula and the islands because early Seri Indian inhabitants transported them there from the mainland as food sources thousands of years ago. This theory is based on the fact that the coastal distribution on the mainland ends 115km south of Isla San Esteban. Contrary to predictions from ecological nicheEcological niche
In ecology, a niche is a term describing the relational position of a species or population in its ecosystem to each other; e.g. a dolphin could potentially be in another ecological niche from one that travels in a different pod if the members of these pods utilize significantly different food...
theory, the species coexists with the giant San Esteban Chuckwalla
San Esteban Chuckwalla
The San Esteban chuckwalla is a species of chuckwalla belonging to the Iguanidae family endemic to San Esteban Island in the Sea of Cortés...
on San Esteban Island
San Esteban Island
San Esteban Island is a small island in the Gulf of California, Mexico, located to the southwest of Tiburón Island. It is part of the Municipality of Hermosillo in Sonora, and has a land area of 39.773 km² , the 15th-largest island in Mexico. It is located in the Sea of Cortés...
. The two species forage for the same plants in the same habitat at the same time of day during the same season, with neither species displacing the other.
The Cape Spinytail iguana makes its den in old woodpecker
Woodpecker
Woodpeckers are near passerine birds of the order Piciformes. They are one subfamily in the family Picidae, which also includes the piculets and wrynecks. They are found worldwide and include about 180 species....
nests in giant columnar cacti, and in other tree cavities. The most important factors determining the choice of cactus are the existence of other holes, and the cactus height because these types of refuges allow the lizards to feed and bask on the tree, minimizing the risk of predation.
The existence of mainland and insular populations of this species has been valuable in providing biologists with study and control groups comparing the evolution
Evolution
Evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...
of island populations.
Description
The Cape Spinytail iguana has a green or yellow coloring when young and turns whitish gray with age. As this animal matures it can be white or light gray in color with black chevrons, depending on heat conditions or even the animal's temper.Males achieve a maximum length of 100 centimetres (39.4 in), while females are typically 30% smaller at 70 centimetres (27.6 in). Males develop large jowls and a dorsal crest made up of larger dorsal spines, making the animal sexually dimorphic
Sexual dimorphism
Sexual dimorphism is a phenotypic difference between males and females of the same species. Examples of such differences include differences in morphology, ornamentation, and behavior.-Examples:-Ornamentation / coloration:...
.
Diet
Like most iguanids, the Cape Spinytail iguana is primarily herbivorous, eating flowerFlower
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants . The biological function of a flower is to effect reproduction, usually by providing a mechanism for the union of sperm with eggs...
s, leaves, stems, fruit
Fruit
In broad terms, a fruit is a structure of a plant that contains its seeds.The term has different meanings dependent on context. In non-technical usage, such as food preparation, fruit normally means the fleshy seed-associated structures of certain plants that are sweet and edible in the raw state,...
, and cactus
Cactus
A cactus is a member of the plant family Cactaceae. Their distinctive appearance is a result of adaptations to conserve water in dry and/or hot environments. In most species, the stem has evolved to become photosynthetic and succulent, while the leaves have evolved into spines...
such as the bushy Jatropha cuneata and the taller, spindly Solanum hindsianum. They will opportunistically eat smaller animals, eggs, and arthropod
Arthropod
An arthropod is an invertebrate animal having an exoskeleton , a segmented body, and jointed appendages. Arthropods are members of the phylum Arthropoda , and include the insects, arachnids, crustaceans, and others...
s.