Transcript Introduction to the Myxini

Myxini
By: Elliott Pilcher, Nathan Wilson, Litsa Doumakis, & Lindsey
Larder-Hylands
Introduction
Myxini is a class
Hagfish or Hyperotreti
Living fossils
Over 67 different
species
• Only animal in the
world to have only a
cranium
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Evolution of the Myxini
• Approximately 500 million years old
• Scientists originally thought that the Hagfish was a
parasite
• They are now known to be predators and scavengers
• Vertebrates and Hagfish evolved seperately for the past
500 million years
• Only one fossil has been found from 330 million years
ago
• The fossilized version of the Hagfish was very similar to the
Hagfish we see today
• Hagfish and Lampreys are the only surviving lineages of
jawless fish.
• Considered an Ancestral Fish
Characteristics
eel shaped
no jaw or any bone structure.
has two rows of sharp teeth.
they usually average around 18 inches
brown color
has poor eyesight but a good sense of smell
no scales but has soft skin
four pairs of sensing tentacles around its mouth
spineless.
has a skull to enclose its brain and a notochord made of
cartilage
• digestive system lacks a stomach
• has four hearts
• produces a slime to protect itself from its predators
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Habitat
• Reside in deep water regions where there is mud to burrow in
• Can be found throughout both northern and southern
hemispheres
• The warmer the region they are found, the deeper they will
reside in the water
• Can be found at very great depths, with the deepest to date
being 1700m into the ocean
• Lack osmoregulation, meaning they require salinity in their
environment at all times. Any sudden change in the salinity of
a hagfish region could result in a sharp decline in population
• Can occasionally be found on rocky bottoms, where the
rocks serve the same purpose as the mud, the hagfish use
them to hide under and in-between from predators
• Most typically found in temperate and cold waters
Video Of Hagfish Slime
• http://youtu.be/pmaal7Hf0WA
Reproduction
• The hagfish has direct development, it goes directly from the
fertilized egg to a young stage without going through the
larvae stage, which means it does not have a larvae stage,
compared to a lamprey
• Only the Japanese Hagfish so far has a regular annual
reproductive cycle and undergoes a regular
• The Hagfish’s kidney(s) are drained through a duct. Unlike
many other vertebrates, this duct is separate from the
reproductive tract.
• Unlike all other vertebrates, the proximal tubule of the nephron
is also connected with the coelom, provided lubrication.
• The single testicle or ovary has no transportation duct.
• Instead, the gametes are released into the coelom until they
find their way to the posterior end of the caudal region,
whereby they find an opening in the digestive system.
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Fun
Facts
In many parts of the
world, including the US,
hagfish-skin clothing,
belts, or other accessories
are advertised and sold
as "yuppie leather" or
"eel-skin”(hagfish are not
true eels, which are bony
fish with jaws).
• Hagfish is eaten in Korea
and other Asian
countries, along with its
eggs and its slime.
• The section of the fishing
industry devoted to
hagfish-fishing has grown
in recent years.
Fun Facts
• Swarms of hagfish
will descend upon
and penetrate the
carcass of its prey
and devour it from
the inside out.
• As well the hagfish
covers the carcass
they are devouring
in slime to deter
other predators
from finding it.
• Sneezing is a way
it prevents the
hagfish from
choking on its own
slime
Sources
• "Animal Diversity Web." Animal Diversity Web. N.p., n.d.
Web. 25 Mar. 2014.
<http://animaldiversity.ummz.umich.edu/accounts/Epta
tretus_stoutii/>.
• "Atlantic Hagfish." - Deep Sea Creatures on Sea and Sky.
N.p., n.d. Web. 25 Mar. 2014.
<http://www.seasky.org/deep-sea/atlantichagfish.html>.
• "Atlantic Hagfish - Myxine Glutinosa." Atlantic Hagfish Myxine Glutinosa. N.p., n.d. Web. 25 Mar. 2014.
<http://www.seawater.no/fauna/chordata/glutinosa.ht
ml>.
• "Atlantic Hagfish: Natural History Notebooks." Atlantic
Hagfish: Natural HistoryNotebooks. N.p., n.d. Web. 25
Mar. 2014.
<http://nature.ca/notebooks/english/atlantichagfish.ht
m>.
Sources
• "Hagfish." Hagfish. N.p., n.d. Web. 25 Mar. 2014.
<http://www.aquaticcommunity.com/mix/hagfish.php>.
• "Introduction to the Myxini." Introduction to the Myxini.
N.p., n.d. Web. 25 Mar. 2014.
<http://www.ucmp.berkeley.edu/vertebrates/basalfish/
myxini.html>.
• "MODERN JAWLESS FISH: HAGFISH & LAMPREYS." Natural
History Collections:. N.p., n.d. Web. 25 Mar. 2014.
<http://www.nhc.ed.ac.uk/index.php?page=493.470.48
0>.
• "Why Evolution Is True." Why Evolution Is True. N.p., n.d.
Web. 25 Mar. 2014.
<http://whyevolutionistrue.wordpress.com/2011/11/21/h
agfish-hagfish-hagfish/>.