Download Sea Anemone - Urban Habitats

Starlet sea anemone
Overview
• Kingdom:Animalia
• Phylum: Cnidaria
• Class: Anthozoa
• Order: Actiniaria
• Suborder: Nyantheae
• Family: Edwardsiidae
• Genus: Nematostella
• Species: Nematostella vectensis
Like all members of the order Actiniaria, the starlet sea
anemone is a solitary marine polyp
Origin
Nematostella vectensis - the Starlet Sea Anemone in
brackish Lagoons at Bembridge Harbour. This species
was first described from the brackish lagoon of
Bembridge Pond by T.A.Stephenson in 1935. Bembridge
is therefore the species Type-locality and the specific
name vectensis comes from the Roman name VECTIS
for the Isle of Wight.
It is nationally scarce, known only from a few brackish
lagoons on the south coast of England.
The length of the animal is probably not much more than
15mm
Description
The starlet sea anemone
has a bulbous basal end
and a contracting column
(usually less than two cm
but no more than six cm)
in order to burrow into the
mud.
At the top of the column is an oral disk containing the mouth surrounded
by two rings of tentacles. The Tentacles are large in proportion to body,
colorless and translucent with pale tips and with faint transverse bars
and irregular flecks of white. The tentacles (9 - 18) are very strongly
adhesive. Although the general color is a grayish white, recent food
consumption may temporarily affect pigmentation.
By pushing its basal end into the mud and
contracting its column, this anemone burrows
into fine mud in order to secure itself against
water currents.
Habitat
This species of sea anemone
lives in salt marshes along
the coast of the United
Kingdom, as well as the east
and west coasts of the United
States. Populations have also
been located in Nova Scotia,
Canada.
Lives in isolated or semiisolated brackish lagoons at
or above high water,
typically in mud, muddy
sand and muddy shingle but
is also found on vegetation.
Life cycle
• Like all anemones, the starlet sea anemones can
reproduce either sexually or asexually.
• Asexual reproduction occurs by division of the body.
In sexual reproduction, females release eggs which
are fertilized by sperm released by males. It occurs
during summer or fall. Fertilized eggs mature into
larvae which metamorphose ( Think of caterpillars and
butterflies) into anemones.
Nematostella development
Nv-muscle LIM
Nematostella development
•In Nematostella,
the sexes are
separate and adults
generate either
eggs or sperm.
•The cleavage
program is chaotic
with no two
embryos developing
identically.
•(A) A hollow blastula is formed
•(B) Gastrulation proceeds by the invagination of the
future oral end of the embryo .
•(C) The planula `larva' is initially shaped like a teardrop
and swims with its apical sensory tuft (at) directed
forward.
• (D) The coelenterons (gut cavity) has formed by the
hollowing out of the solid planula.
• (E) The polyp forms 7 days after fertilization. When it
first settles onto the substrate, it has four tentacles and
eight endodermal mesenteries. Endoderm lines the hollow
tentacles
Starlet Sea Anemone’s
Prey
• The Starlet Sea
• Starlet Sea Anemone
Anemone feeds on
insects larvae, worms,
snails, crustaceans and
anything that can feed
their mouths.
• They capture their
preys with tentacles
releases stinging cells
to immobilize and kill
the prey.
• Anemones are
uneatable by other
organisms.
Food Habits
• This species is remarkably unselective in its
food consumption; it eats mainly copepods
and midge larvae. The tentacles trap prey,
then the cilia beat downward creating a
water flow helping pull the food from the
oral disk into the gastrovascular cavity for
consumption.
Bibliography
 http/www.nematostella.org
 http://www.marlin.ac.uk/
www.animaldiversity.edu/
 Mr. Sullivan’s handout