Tropical Thornytail Iguana
Encyclopedia
The Tropical Thornytail Iguana or Amazon Thornytail Iguana, Uracentron flaviceps, is an elusive species of medium sized arboreal lizard found in the tropical lowlands of the Amazon Rainforest
. The species was described by French
zoologist Alphone Guichenot
in 1855. They are considered to be ant
specialists and exhibit communal nesting and a harem style breeding system in which there is one male to multiple females. Study of this species has been impeded by difficulties collecting and observing the species.
was split into several genera and the Tropical Thornytail Iguana was assigned to Uracentron
.
, eastern Peru
, northwestern Brazil
, and in the extreme southern regions of Colombia
, they may be found in Bolivia
as well.
, and palm swamp
s.
They are an arboreal species, spending the majority of their life in high tree tops. They prefer trees with high horizontal branches that allow for basking in the sun during the morning hours, and are almost only found in trees that contain hollow areas accessible through entrances in the tree branches and trunks. No specific species of tree has been found to be favored by the lizards, it would appear the tree structure, rather than the tree species, is what the lizards prefer.
. The males display longer and deeper heads, as well as longer limbs when compared to females. Females are also generally a little bit shorter in length than males.
Sexually mature males also display different coloration than females or juveniles. Sexually mature males have an orange head and black body, in contrast to the much more subdued coloring and yellow heads of females, juveniles, and not sexually mature males. Males that reach sexual maturity also have enlarged testes when compared to those of males that have not reached sexual maturity.
. They are considered ant specialists, and various species of ants that wander the limbs and trunks of the trees inhabited by Tropical Thornytail Iguanas make up a large percentage of their diet. Larger lizards will eat slightly larger prey as well such as stingless bees, hemiptera
ns (also known as true bugs), and beetles. Interestingly alate
s, which have been established as a prey item of the Tropical Thornytail Iguana are not usually present on the limbs and trunks of trees. It is possible that the lizards will break into the alate nests in the trees, or that they may only eat the species when releases occur. If they do break into the nests it is a highly unusual behavior, as rarely will an ambush predator actively seek its prey. In studies investigating the eating behaviors of this species there was no difference in the amount of prey consumed between male and female specimens. This indicates that resource partitioning is not the reason for the difference in head size between and male and female Tropical Thornytail Iguanas.
social structure in which there is one sexually mature male to a group of females and juveniles. Resource defense polygyny means that the females do not necessarily live in extremely close quarters but the resources the females need are clustered together. This creates a group of females, and the resources they need, that a male can claim as his territory. This allows the male to be polygynous with minimal effort defending a resource-based territory. In the case of Tropical Thornytail Iguanas there is usually one group of lizards per tree with one dominate male. The structure of the system is usually one male, several adult females and various juveniles at different stages. In the few cases where there are two large adult males per tree it was found that the old male would take the dominate role and display the orange head and black body of a sexually mature male, whereas the other male will display the coloration patterns of an adult female. It has been mentioned that the lack of coloration shown by the younger male may be because the presence of a large old male suppresses the reproductive receptivity of the younger male. In cases where there is only one lizard in a tree, it is generally a male without a group of females.
for this species appears to be extended, based on observations of juveniles of different sizes in a single tree. During the breeding season males become more territorial and will engage in displays of head bobbing and body movements to warn away other males who may try to infringe on their territory. These displays are also used to attract a potential mate. Like most reptiles Tropical Thornytail Iguanas are oviparous and lay clutches of eggs. For this species clutches are usually 2 eggs per female, and clutches smaller than 2 eggs are very rare. The eggs are laid in nests deep within the holes of trees inhabited by a group of Tropical Thornytail Iguanas.
Amazon Rainforest
The Amazon Rainforest , also known in English as Amazonia or the Amazon Jungle, is a moist broadleaf forest that covers most of the Amazon Basin of South America...
. The species was described by French
French people
The French are a nation that share a common French culture and speak the French language as a mother tongue. Historically, the French population are descended from peoples of Celtic, Latin and Germanic origin, and are today a mixture of several ethnic groups...
zoologist Alphone Guichenot
Alphone Guichenot
Antoine Alphone Guichenot was a French zoologist who taught, researched, and participated in specimen collecting trips on behalf of the National Natural History Museum in Paris, including an extensive biological survey of Algeria. His primary fields of research included fish and reptiles...
in 1855. They are considered to be ant
Ant
Ants are social insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants evolved from wasp-like ancestors in the mid-Cretaceous period between 110 and 130 million years ago and diversified after the rise of flowering plants. More than...
specialists and exhibit communal nesting and a harem style breeding system in which there is one male to multiple females. Study of this species has been impeded by difficulties collecting and observing the species.
Taxonomy
The species was originally named Doryphorus flaviceps by Guichenot in 1855. Since it's original discovery the species has undergone a number of taxonomic changes. In 1881 it was renamed Uranocentruum flaviceps by O'Shaughnessy. This change did not last very long and the name was changed to Urocentron castor in 1885. There were only minor taxonomic changes after 1885 until a change to Uracentron flaviceps in 1925. This name lasted until 1992 when Darrel R. Frost renamed the species Tropidurus flaviceps. This name did not last very long, and the name switched between Tropidurus flaviceps and Uracentron flaviceps until 2003, when the genus TropidurusTropidurus
The reptile genus Tropidurus includes several species of Neotropical ground lizards . It is the type genus of this family of iguanian lizards. They are found on the South American mainland, especially in the Amazon Rainforest but also in more arid regions...
was split into several genera and the Tropical Thornytail Iguana was assigned to Uracentron
Uracentron
Uracentron is a genus of Tropidurid lizards. It contains only two described species at present.Genus Uracentron*Uracentron azureum*Uracentron flaviceps...
.
Distribution
The species has been noted in the lowlands of eastern EcuadorEcuador
Ecuador , officially the Republic of Ecuador is a representative democratic republic in South America, bordered by Colombia on the north, Peru on the east and south, and by the Pacific Ocean to the west. It is one of only two countries in South America, along with Chile, that do not have a border...
, eastern Peru
Peru
Peru , officially the Republic of Peru , is a country in western South America. It is bordered on the north by Ecuador and Colombia, on the east by Brazil, on the southeast by Bolivia, on the south by Chile, and on the west by the Pacific Ocean....
, northwestern Brazil
Brazil
Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...
, and in the extreme southern regions of Colombia
Colombia
Colombia, officially the Republic of Colombia , is a unitary constitutional republic comprising thirty-two departments. The country is located in northwestern South America, bordered to the east by Venezuela and Brazil; to the south by Ecuador and Peru; to the north by the Caribbean Sea; to the...
, they may be found in Bolivia
Bolivia
Bolivia officially known as Plurinational State of Bolivia , is a landlocked country in central South America. It is the poorest country in South America...
as well.
Habitat
Tropical Thornytail Iguanas are only found in the Amazon Rainforest, and within the rainforest are generally found in lowland tropical rainforest; usually areas with lagoons, rivers, streamsSTREAMS
In computer networking, STREAMS is the native framework in Unix System V for implementing character devices.STREAMS was designed as a modular architecture for implementing full-duplex I/O between kernel or user space processes and device drivers. Its most frequent uses have been in developing...
, and palm swamp
Swamp
A swamp is a wetland with some flooding of large areas of land by shallow bodies of water. A swamp generally has a large number of hammocks, or dry-land protrusions, covered by aquatic vegetation, or vegetation that tolerates periodical inundation. The two main types of swamp are "true" or swamp...
s.
They are an arboreal species, spending the majority of their life in high tree tops. They prefer trees with high horizontal branches that allow for basking in the sun during the morning hours, and are almost only found in trees that contain hollow areas accessible through entrances in the tree branches and trunks. No specific species of tree has been found to be favored by the lizards, it would appear the tree structure, rather than the tree species, is what the lizards prefer.
Physical description
This species is considered a medium sized lizard, generally around 8 inches in length. They have a large, flat tail covered in scales that end in a point; the function of these scales is currently unclear. The body is brown in color, speckled with yellow or gold spots. Some specimens found in Ecuador and Peru were noted as having a black collar around their necks. This collar is bordered by narrow light colored edges.Sexual dimorphism
Sexually mature males differ from females, and juveniles in appearance, and it has been hypothesized that this may be the result of sexual selectionSexual selection
Sexual selection, a concept introduced by Charles Darwin in his 1859 book On the Origin of Species, is a significant element of his theory of natural selection...
. The males display longer and deeper heads, as well as longer limbs when compared to females. Females are also generally a little bit shorter in length than males.
Sexually mature males also display different coloration than females or juveniles. Sexually mature males have an orange head and black body, in contrast to the much more subdued coloring and yellow heads of females, juveniles, and not sexually mature males. Males that reach sexual maturity also have enlarged testes when compared to those of males that have not reached sexual maturity.
Feeding and diet
Tropical Thornytail Iguanas are considered a sit and wait, or ambush predatorAmbush predator
Ambush predators or sit-and-wait predators are carnivorous animals that capture prey by stealth or cunning, not by speed or necessarily by strength. These organisms usually hide motionless and wait for prey to come within striking distance. They are often camouflaged, and may be solitary...
. They are considered ant specialists, and various species of ants that wander the limbs and trunks of the trees inhabited by Tropical Thornytail Iguanas make up a large percentage of their diet. Larger lizards will eat slightly larger prey as well such as stingless bees, hemiptera
Hemiptera
Hemiptera is an order of insects most often known as the true bugs , comprising around 50,000–80,000 species of cicadas, aphids, planthoppers, leafhoppers, shield bugs, and others...
ns (also known as true bugs), and beetles. Interestingly alate
Alate
An alate is a winged reproductive of a social insect . Alate females are typically those destined to become queens , whereas alate males are occasionally referred to as "drones"...
s, which have been established as a prey item of the Tropical Thornytail Iguana are not usually present on the limbs and trunks of trees. It is possible that the lizards will break into the alate nests in the trees, or that they may only eat the species when releases occur. If they do break into the nests it is a highly unusual behavior, as rarely will an ambush predator actively seek its prey. In studies investigating the eating behaviors of this species there was no difference in the amount of prey consumed between male and female specimens. This indicates that resource partitioning is not the reason for the difference in head size between and male and female Tropical Thornytail Iguanas.
Behavior
The species is diurnal, active during the daytime. The level of activity exhibited is at least partially dependent on the presence of sunlight. Individuals emerge once the sun comes out, and will remain active unless cloud cover reduces sunlight. The approximate times of activity are from 8:30am until 5:00pm and males appear to emerge from holes in tress earlier than females and juveniles. Upon emerging from the tree lizards will bask in the sun to raise their body temperature until activity body temperatures are reached. When approached by humans or startled the lizards will either run into their holes to hide or run out on limbs of the tree to avoid whatever startled them.Social structure
The Tropical Thornytail Iguana has a resource defense polygynyPolygyny
Polygyny is a form of marriage in which a man has two or more wives at the same time. In countries where the practice is illegal, the man is referred to as a bigamist or a polygamist...
social structure in which there is one sexually mature male to a group of females and juveniles. Resource defense polygyny means that the females do not necessarily live in extremely close quarters but the resources the females need are clustered together. This creates a group of females, and the resources they need, that a male can claim as his territory. This allows the male to be polygynous with minimal effort defending a resource-based territory. In the case of Tropical Thornytail Iguanas there is usually one group of lizards per tree with one dominate male. The structure of the system is usually one male, several adult females and various juveniles at different stages. In the few cases where there are two large adult males per tree it was found that the old male would take the dominate role and display the orange head and black body of a sexually mature male, whereas the other male will display the coloration patterns of an adult female. It has been mentioned that the lack of coloration shown by the younger male may be because the presence of a large old male suppresses the reproductive receptivity of the younger male. In cases where there is only one lizard in a tree, it is generally a male without a group of females.
Reproduction
The breeding seasonBreeding season
The breeding season is the most suitable season, usually with favourable conditions and abundant food and water, for breeding among some wild animals and birds . Species with a breeding season have naturally evolved to have sexual intercourse during a certain time of year in order to achieve the...
for this species appears to be extended, based on observations of juveniles of different sizes in a single tree. During the breeding season males become more territorial and will engage in displays of head bobbing and body movements to warn away other males who may try to infringe on their territory. These displays are also used to attract a potential mate. Like most reptiles Tropical Thornytail Iguanas are oviparous and lay clutches of eggs. For this species clutches are usually 2 eggs per female, and clutches smaller than 2 eggs are very rare. The eggs are laid in nests deep within the holes of trees inhabited by a group of Tropical Thornytail Iguanas.
Conservation
The conservation status of the Tropical Thornytail Iguana is currently uncertain, but it is thought that the loss of the species' preferred habitat to deforestation is the main threat to the species.Further reading
- Its A Jungle Up There, by Margaret D. LowmanMargaret D. LowmanMargaret D. Lowman, Ph.D. a.k.a "Canopy Meg" received a B.A. with honors in biology and environmental studies from Williams College , M.S. in ecology from Aberdeen University , and Ph.D. in botany from the University of Sydney . Dr...
, E. Burgess, and J. Burgess (Yale University Press) - Contains more information on the canopy research in this region, including reptiles.
External links
- The Jason Expedition - This Expedition was located at the Amazon Center for Tropical Studies canopy walkway Platform #6, where there is a thriving population of Tropical Thornytail Iguanas. All photos used in this page were taken from Platform #6.
- Canopy Meg - Contact Dr. Meg Lowman for information-sharing on the Tropical Thornytail Iguana, or other canopy dynamics from this region.