8/13/2019 Caecilian
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Description
Caecilians completely lack limbs, making the smaller species
resemble worms, while the larger
species, with lengths up to 1.5 m (4 ft 11 in), resemble snakes.
Their tails are short or absent, andtheir cloacaeare near the ends
of their bodies.!"#"4"
Their skin is smooth and usually dark$matte, but some species
ha%e colorful skins. &nside the
skin are calcitescales. 'ecause of these scales, the caecilians
were once thought to be related to
the fossil tegocephalia, but they are now belie%ed to be a
secondary de%elopment, and the twogroups are most likely
unrelated.4"The skin also has numerous ring$shaped folds, or
annuli, that
partially encircle the body, gi%ing them a segmented appearance.
ike some other li%ing
amphibians, the skin contains glands that secrete a to*in to
deter predators. 1"The skin secretionsof Siphonops paulensisha%e
been shown to ha%e hemolyticproperties.5"
Caecilians+ %ision is limited to dark$light perception,"and
their anatomy is highly adapted for a
burrowing lifestyle. They ha%e a strong skull, with a pointed
snout used to force their way
through soil or mud.4"&n most species, the bones in the
skull are reduced in number and fusedtogether, and the mouth is
recessed under the head. Their muscles are adapted to pushing
their
way through the ground, with the skeleton and deep muscles
acting as a piston inside the skin
and outer muscles. This allows the animal to anchor its hind end
in position, and force the headforwards, and then pull the rest of
the body up to reach it in wa%es. &n water or %ery loose
mud,
caecilians instead swim in an eel$like fashion.1"Caecilians in
the family Typhlonectidaeare
a-uatic, and the largest of their kind. The representati%es of
this family ha%e a fleshy fin runningalong the rear section of
their bodies, which enhances propulsion in water."
/ll but the most primiti%e caecilians ha%e two sets of muscles
for closing the 0aw, compared with
the single pair found in other creatures. These are more highly
de%eloped in the most efficient
burrowers among the caecilians, and appear to help keep the
skull and 0aw rigid.1"
/dapting to their underground life, the eyes are small and
co%ered by skin for protection, whichhas led to the misconception
that they are blind. This is not strictly true, although their
sight is
limited to simple dark$light perception. /ll caecilians possess
a pair of tentacles, located between
their eyes and nostrils. These are probably used for a
secondolfactory capability,in addition tothe normal sense of smell
based in the nose.1"
*cept for two lungless species 2Atretochoana eiselti3" and
Caecilita iwokramae" 2 all
caecilians ha%e lungs, but also use their skin or mouths for
o*ygenabsorption. ften, the left
lung is much smaller than the right one, an adaptation to body
shape that is also found in snakes.
citation needed"
Distribution
Caecilians are found in wet, tropical regions of outheast /sia,
&ndia, 'angladesh, and ri
anka, parts of ast and 6est /frica, the eychelles&slands in
the &ndian cean, Central/merica, and in northern and eastern
outh /merica. &n /frica, caecilians are found from
http://en.wikipedia.org/wiki/Cloacahttp://en.wikipedia.org/wiki/Caecilian#cite_note-2http://en.wikipedia.org/wiki/Caecilian#cite_note-3http://en.wikipedia.org/wiki/Caecilian#cite_note-Brittanica-4http://en.wikipedia.org/wiki/Calcitehttp://en.wikipedia.org/wiki/Scale_(zoology)http://en.wikipedia.org/wiki/Stegocephaliahttp://en.wikipedia.org/wiki/Caecilian#cite_note-Brittanica-4http://en.wikipedia.org/wiki/Caecilian#cite_note-Brittanica-4http://en.wikipedia.org/wiki/Caecilian#cite_note-EoR-1http://en.wikipedia.org/wiki/Haemolysishttp://en.wikipedia.org/wiki/Caecilian#cite_note-5http://en.wikipedia.org/wiki/Caecilian#cite_note-6http://en.wikipedia.org/wiki/Caecilian#cite_note-Brittanica-4http://en.wikipedia.org/wiki/Caecilian#cite_note-EoR-1http://en.wikipedia.org/wiki/Typhlonectidaehttp://en.wikipedia.org/wiki/Typhlonectidaehttp://en.wikipedia.org/wiki/Caecilian#cite_note-7http://en.wikipedia.org/wiki/Caecilian#cite_note-EoR-1http://en.wikipedia.org/wiki/Olfactionhttp://en.wikipedia.org/wiki/Olfactionhttp://en.wikipedia.org/wiki/Olfactionhttp://en.wikipedia.org/wiki/Caecilian#cite_note-EoR-1http://en.wikipedia.org/wiki/Atretochoana_eiseltihttp://en.wikipedia.org/wiki/Atretochoana_eiseltihttp://en.wikipedia.org/wiki/Caecilian#cite_note-8http://en.wikipedia.org/wiki/Atretochoana_eiseltihttp://en.wikipedia.org/wiki/Caecilita_iwokramaehttp://en.wikipedia.org/wiki/Caecilian#cite_note-9http://en.wikipedia.org/wiki/Caecilian#cite_note-9http://en.wikipedia.org/wiki/Lunghttp://en.wikipedia.org/wiki/Oxygenhttp://en.wikipedia.org/wiki/Oxygenhttp://en.wikipedia.org/wiki/Wikipedia:Citation_neededhttp://en.wikipedia.org/wiki/Wikipedia:Citation_neededhttp://en.wikipedia.org/wiki/Seychelleshttp://en.wikipedia.org/wiki/Caecilian#cite_note-2http://en.wikipedia.org/wiki/Caecilian#cite_note-3http://en.wikipedia.org/wiki/Caecilian#cite_note-Brittanica-4http://en.wikipedia.org/wiki/Calcitehttp://en.wikipedia.org/wiki/Scale_(zoology)http://en.wikipedia.org/wiki/Stegocephaliahttp://en.wikipedia.org/wiki/Caecilian#cite_note-Brittanica-4http://en.wikipedia.org/wiki/Caecilian#cite_note-EoR-1http://en.wikipedia.org/wiki/Haemolysishttp://en.wikipedia.org/wiki/Caecilian#cite_note-5http://en.wikipedia.org/wiki/Caecilian#cite_note-6http://en.wikipedia.org/wiki/Caecilian#cite_note-Brittanica-4http://en.wikipedia.org/wiki/Caecilian#cite_note-EoR-1http://en.wikipedia.org/wiki/Typhlonectidaehttp://en.wikipedia.org/wiki/Caecilian#cite_note-7http://en.wikipedia.org/wiki/Caecilian#cite_note-EoR-1http://en.wikipedia.org/wiki/Olfactionhttp://en.wikipedia.org/wiki/Caecilian#cite_note-EoR-1http://en.wikipedia.org/wiki/Atretochoana_eiseltihttp://en.wikipedia.org/wiki/Caecilian#cite_note-8http://en.wikipedia.org/wiki/Caecilita_iwokramaehttp://en.wikipedia.org/wiki/Caecilian#cite_note-9http://en.wikipedia.org/wiki/Lunghttp://en.wikipedia.org/wiki/Oxygenhttp://en.wikipedia.org/wiki/Wikipedia:Citation_neededhttp://en.wikipedia.org/wiki/Seychelleshttp://en.wikipedia.org/wiki/Cloaca
8/13/2019 Caecilian
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7uinea$'issau (Geotrypetes) to southern 8alawi (Scolecomorphus),
with an unconfirmed record
from eastern 9imbabwe. They ha%e not been recorded from the
e*tensi%e areas of tropical forest
in central /frica. &n outh /merica, they e*tend through
subtropical eastern 'ra:il well intotemperate northern /rgentina.
They can be seen as far south as 'uenos /ires,when they are
carried by the flood waters of the ;aran< =i%ercoming from
farther north. Their /merican range
e*tends north to southern 8e*ico. The northernmost distribution
is of the speciesIchthyophissikkimensisof northern
&ndia.Ichthyophisis also found in outh China and >orth
?ietnam. &n
outheast /sia, they are found as far east as @a%a, 'orneo, and
the southern ;hilippines, but they
ha%e not crossed 6allace+s lineand are not present in /ustralia
or nearby islands.citation needed"
Taxonomy
Ichthyophisfrom the an /ntonio 9oo
The name caecilianderi%es from the atin word caecus, meaning
AblindA, referring to the small
or sometimes none*istent eyes. The name dates back to the
ta*onomic name of the first speciesdescribed by Carolus
innaeus,which he named Caecilia tentaculata.4"The order name
deri%es
from the 7reek words BDEFG (gymnos, naked) and FHIG (ophis,
snake), as the caecilians wereoriginally thought to be related to
snakes.citation needed"
The most recent classification of caecilians, by 6ilkinson et
al. (!J11), di%ided the7ymnophiona into families containing nearly
!JJ species.1J"ince then, a tenth caecilian
family has been disco%ered, Chikilidae.11"1!"This classification
is based on a thorough definition
of monophyly based on morphological and molecular
e%idence,1#"14"15"1"and it sol%es thelongstanding problems
ofparaphylyof the Caeciliidaein pre%ious classifications without
an
e*clusi%e reliance upon synonymy.1J"1"
=hinatrematidae $ ! genera, 11 speciesK outh /merica
&chthyophiidae $ # genera, 5J speciesK outh and outheast
/sia
colecomorphidae $ ! genera, speciesK /frica
Lerpelidae $ ! genera, speciesK /frica
Chikilidae $ 1 genus, # speciesK &ndia
Caeciliidae $ ! genera, 4! speciesK outh and Central /merica
http://en.wikipedia.org/wiki/Buenos_Aireshttp://en.wikipedia.org/wiki/Buenos_Aireshttp://en.wikipedia.org/wiki/Paran%C3%A1_Riverhttp://en.wikipedia.org/wiki/Ichthyophishttp://en.wikipedia.org/wiki/Wallace's_linehttp://en.wikipedia.org/wiki/Wikipedia:Citation_neededhttp://en.wikipedia.org/wiki/Wikipedia:Citation_neededhttp://en.wikipedia.org/wiki/Wikipedia:Citation_neededhttp://en.wikipedia.org/wiki/Ichthyophishttp://en.wikipedia.org/wiki/San_Antonio_Zoohttp://en.wiktionary.org/wiki/caecushttp://en.wikipedia.org/wiki/Carolus_Linnaeushttp://en.wikipedia.org/wiki/Carolus_Linnaeushttp://en.wikipedia.org/wiki/Caecilian#cite_note-Brittanica-4http://en.wikipedia.org/wiki/Caecilian#cite_note-Brittanica-4http://en.wikipedia.org/wiki/Wikipedia:Citation_neededhttp://en.wikipedia.org/wiki/Wikipedia:Citation_neededhttp://en.wikipedia.org/wiki/Caecilian#cite_note-nine-family-10http://en.wikipedia.org/wiki/Chikilidaehttp://en.wikipedia.org/wiki/Caecilian#cite_note-Chiklidae-11http://en.wikipedia.org/wiki/Caecilian#cite_note-12http://en.wikipedia.org/wiki/Caecilian#cite_note-12http://en.wikipedia.org/wiki/Caecilian#cite_note-13http://en.wikipedia.org/wiki/Caecilian#cite_note-14http://en.wikipedia.org/wiki/Caecilian#cite_note-15http://en.wikipedia.org/wiki/Caecilian#cite_note-16http://en.wikipedia.org/wiki/Caecilian#cite_note-16http://en.wikipedia.org/wiki/Paraphylyhttp://en.wikipedia.org/wiki/Caeciliidaehttp://en.wikipedia.org/wiki/Caeciliidaehttp://en.wikipedia.org/wiki/Caecilian#cite_note-nine-family-10http://en.wikipedia.org/wiki/Caecilian#cite_note-17http://en.wikipedia.org/wiki/Rhinatrematidaehttp://en.wikipedia.org/wiki/Ichthyophiidaehttp://en.wikipedia.org/wiki/Scolecomorphidaehttp://en.wikipedia.org/wiki/Herpelidaehttp://en.wikipedia.org/wiki/Chikilidaehttp://en.wikipedia.org/wiki/Caeciliidaehttp://en.wikipedia.org/wiki/File:Caecilian.jpghttp://en.wikipedia.org/wiki/File:Caecilian.jpghttp://en.wikipedia.org/wiki/Buenos_Aireshttp://en.wikipedia.org/wiki/Paran%C3%A1_Riverhttp://en.wikipedia.org/wiki/Ichthyophishttp://en.wikipedia.org/wiki/Wallace's_linehttp://en.wikipedia.org/wiki/Wikipedia:Citation_neededhttp://en.wikipedia.org/wiki/Ichthyophishttp://en.wikipedia.org/wiki/San_Antonio_Zoohttp://en.wiktionary.org/wiki/caecushttp://en.wikipedia.org/wiki/Carolus_Linnaeushttp://en.wikipedia.org/wiki/Caecilian#cite_note-Brittanica-4http://en.wikipedia.org/wiki/Wikipedia:Citation_neededhttp://en.wikipedia.org/wiki/Caecilian#cite_note-nine-family-10http://en.wikipedia.org/wiki/Chikilidaehttp://en.wikipedia.org/wiki/Caecilian#cite_note-Chiklidae-11http://en.wikipedia.org/wiki/Caecilian#cite_note-12http://en.wikipedia.org/wiki/Caecilian#cite_note-13http://en.wikipedia.org/wiki/Caecilian#cite_note-14http://en.wikipedia.org/wiki/Caecilian#cite_note-15http://en.wikipedia.org/wiki/Caecilian#cite_note-16http://en.wikipedia.org/wiki/Paraphylyhttp://en.wikipedia.org/wiki/Caeciliidaehttp://en.wikipedia.org/wiki/Caecilian#cite_note-nine-family-10http://en.wikipedia.org/wiki/Caecilian#cite_note-17http://en.wikipedia.org/wiki/Rhinatrematidaehttp://en.wikipedia.org/wiki/Ichthyophiidaehttp://en.wikipedia.org/wiki/Scolecomorphidaehttp://en.wikipedia.org/wiki/Herpelidaehttp://en.wikipedia.org/wiki/Chikilidaehttp://en.wikipedia.org/wiki/Caeciliidae
