Lesser Siren
Encyclopedia
The Lesser Siren is a species
of aquatic salamander
native to the eastern United States
and northern Mexico
. They are referred by numerous common names, including Two-legged Eel, Dwarf Siren, and Mud Eel. The epithet intermedia denotes their intermediate size, between the Greater Siren, Siren lacertina, and the Dwarf Siren, Pseudobranchus sp.
, spending its days hidden in the debris and mud at the bottom of slow moving bodies of water. They feed primarily on aquatic invertebrate
s, including various kinds of worms, snail
s, and crustacean
s. They will also eat the tadpole
s and eggs of other amphibian
s.
Reproduction occurs in the spring months, with eggs
being laid in a shallow depression at the bottom of a calm area of water. Usually surrounded by vegetation. Though little is known about their courtship, it is believed to be quite violent, as many specimens collected have scarring from healed bite marks from other sirens. 12-300 eggs are laid at a time, and several clutches may be laid over the course of the year. Hatchlings are only about 0.4 of an inch (1.1 cm) in length, but grow quickly. Maturity is reached in 3–4 years.
The Lesser Siren is vocal, unlike most salamanders, and will emit a series of clicks when they approach others of their species, or a short screeching sound if handled.
If the habitat
dries up during the summer months, Lesser Sirens are capable of excreting a substance from their skin which protects them from dehydrating, and enables them to stay buried in dry mud for months until the water returns. Their small legs enable them to move on dry land for short periods of time.
to Florida
, and west to Texas
(ranging into northeastern Mexico
as far as Veracruz
), and north to Illinois
, Indiana
and Michigan
.
are within Siren intermedia, most agree that there are at least two, an eastern and a western variety. Many sources also include a third subspecies, the Rio Grande Lesser Siren, Siren intermedia texana, but researchers disagree whether the Rio Grande variety belongs as a Lesser Siren, within Siren intermedia, or as a Greater Siren, within Siren lacertina, and some others even consider it to be its own species, as Siren texana.
, it is believed that their numbers are declining due to general reductions in water quality, believed to be caused by agricultural pesticide
and fertilizer
runoff
. They are frequently collected and used as bait
for fishing
. The species is believed to be extirpated
from the state of Michigan
, and the S. i. texana subspecies is listed as a threatened species
in the state of Texas.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of aquatic salamander
Salamander
Salamander is a common name of approximately 500 species of amphibians. They are typically characterized by a superficially lizard-like appearance, with their slender bodies, short noses, and long tails. All known fossils and extinct species fall under the order Caudata, while sometimes the extant...
native to the eastern United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
and northern Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
. They are referred by numerous common names, including Two-legged Eel, Dwarf Siren, and Mud Eel. The epithet intermedia denotes their intermediate size, between the Greater Siren, Siren lacertina, and the Dwarf Siren, Pseudobranchus sp.
Behavior
The Lesser Siren is nocturnalNocturnal animal
Nocturnality is an animal behavior characterized by activity during the night and sleeping during the day. The common adjective is "nocturnal"....
, spending its days hidden in the debris and mud at the bottom of slow moving bodies of water. They feed primarily on aquatic invertebrate
Invertebrate
An invertebrate is an animal without a backbone. The group includes 97% of all animal species – all animals except those in the chordate subphylum Vertebrata .Invertebrates form a paraphyletic group...
s, including various kinds of worms, snail
Snail
Snail is a common name applied to most of the members of the molluscan class Gastropoda that have coiled shells in the adult stage. When the word is used in its most general sense, it includes sea snails, land snails and freshwater snails. The word snail without any qualifier is however more often...
s, and crustacean
Crustacean
Crustaceans form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 described species range in size from Stygotantulus stocki at , to the Japanese spider crab with a leg span...
s. They will also eat the tadpole
Tadpole
A tadpole or polliwog is the wholly aquatic larval stage in the life cycle of an amphibian, particularly that of a frog or toad.- Appellation :...
s and eggs of other amphibian
Amphibian
Amphibians , are a class of vertebrate animals including animals such as toads, frogs, caecilians, and salamanders. They are characterized as non-amniote ectothermic tetrapods...
s.
Reproduction occurs in the spring months, with eggs
Egg (biology)
An egg is an organic vessel in which an embryo first begins to develop. In most birds, reptiles, insects, molluscs, fish, and monotremes, an egg is the zygote, resulting from fertilization of the ovum, which is expelled from the body and permitted to develop outside the body until the developing...
being laid in a shallow depression at the bottom of a calm area of water. Usually surrounded by vegetation. Though little is known about their courtship, it is believed to be quite violent, as many specimens collected have scarring from healed bite marks from other sirens. 12-300 eggs are laid at a time, and several clutches may be laid over the course of the year. Hatchlings are only about 0.4 of an inch (1.1 cm) in length, but grow quickly. Maturity is reached in 3–4 years.
The Lesser Siren is vocal, unlike most salamanders, and will emit a series of clicks when they approach others of their species, or a short screeching sound if handled.
If the habitat
Habitat (ecology)
A habitat is an ecological or environmental area that is inhabited by a particular species of animal, plant or other type of organism...
dries up during the summer months, Lesser Sirens are capable of excreting a substance from their skin which protects them from dehydrating, and enables them to stay buried in dry mud for months until the water returns. Their small legs enable them to move on dry land for short periods of time.
Geographic distribution
The Lesser Siren is found in the United States, primarily from VirginiaVirginia
The Commonwealth of Virginia , is a U.S. state on the Atlantic Coast of the Southern United States. Virginia is nicknamed the "Old Dominion" and sometimes the "Mother of Presidents" after the eight U.S. presidents born there...
to Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
, and west to Texas
Texas
Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...
(ranging into northeastern Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
as far as Veracruz
Veracruz
Veracruz, formally Veracruz de Ignacio de la Llave officially Estado Libre y Soberano de Veracruz de Ignacio de la Llave , is one of the 31 states that, along with the Federal District, comprise the 32 federative entities of Mexico. It is divided in 212 municipalities and its capital city is...
), and north to Illinois
Illinois
Illinois is the fifth-most populous state of the United States of America, and is often noted for being a microcosm of the entire country. With Chicago in the northeast, small industrial cities and great agricultural productivity in central and northern Illinois, and natural resources like coal,...
, Indiana
Indiana
Indiana is a US state, admitted to the United States as the 19th on December 11, 1816. It is located in the Midwestern United States and Great Lakes Region. With 6,483,802 residents, the state is ranked 15th in population and 16th in population density. Indiana is ranked 38th in land area and is...
and Michigan
Michigan
Michigan is a U.S. state located in the Great Lakes Region of the United States of America. The name Michigan is the French form of the Ojibwa word mishigamaa, meaning "large water" or "large lake"....
.
Taxonomy
Sources disagree on the number of subspeciesSubspecies
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...
are within Siren intermedia, most agree that there are at least two, an eastern and a western variety. Many sources also include a third subspecies, the Rio Grande Lesser Siren, Siren intermedia texana, but researchers disagree whether the Rio Grande variety belongs as a Lesser Siren, within Siren intermedia, or as a Greater Siren, within Siren lacertina, and some others even consider it to be its own species, as Siren texana.
- Eastern Lesser Siren, Siren intermedia intermedia (Goin, 1942)
- Western Lesser Siren, Siren intermedia nettingi (Goin, 1942)
- Rio Grande Lesser Siren, Siren intermedia texana (Goin, 1957)
Conservation status
The Lesser Siren is quite common through most of its range, but rarely seen due to its secretive nature. Like almost all species of amphibianAmphibian
Amphibians , are a class of vertebrate animals including animals such as toads, frogs, caecilians, and salamanders. They are characterized as non-amniote ectothermic tetrapods...
, it is believed that their numbers are declining due to general reductions in water quality, believed to be caused by agricultural pesticide
Pesticide
Pesticides are substances or mixture of substances intended for preventing, destroying, repelling or mitigating any pest.A pesticide may be a chemical unicycle, biological agent , antimicrobial, disinfectant or device used against any pest...
and fertilizer
Fertilizer
Fertilizer is any organic or inorganic material of natural or synthetic origin that is added to a soil to supply one or more plant nutrients essential to the growth of plants. A recent assessment found that about 40 to 60% of crop yields are attributable to commercial fertilizer use...
runoff
Surface runoff
Surface runoff is the water flow that occurs when soil is infiltrated to full capacity and excess water from rain, meltwater, or other sources flows over the land. This is a major component of the water cycle. Runoff that occurs on surfaces before reaching a channel is also called a nonpoint source...
. They are frequently collected and used as bait
Bait (luring substance)
Bait is any substance used to attract prey, e.g. in a mousetrap.-In Australia:Baiting in Australia refers to specific campaigns to control foxes, wild dogs and dingos by poisoning in areas where they are a problem...
for fishing
Fishing
Fishing is the activity of trying to catch wild fish. Fish are normally caught in the wild. Techniques for catching fish include hand gathering, spearing, netting, angling and trapping....
. The species is believed to be extirpated
Local extinction
Local extinction, also known as extirpation, is the condition of a species which ceases to exist in the chosen geographic area of study, though it still exists elsewhere...
from the state of Michigan
Michigan
Michigan is a U.S. state located in the Great Lakes Region of the United States of America. The name Michigan is the French form of the Ojibwa word mishigamaa, meaning "large water" or "large lake"....
, and the S. i. texana subspecies is listed as a threatened species
Threatened species
Threatened species are any speciesg animals, plants, fungi, etc.) which are vulnerable to endangerment in the near future.The World Conservation Union is the foremost authority on threatened species, and treats threatened species not as a single category, but as a group of three categories,...
in the state of Texas.