Download sea stars, sea cucumbers, sea urchins and more…

SEA STARS, SEA CUCUMBERS,
SEA URCHINS AND MORE…
Betty Staugler, Florida Sea Grant Agent - UF/IFAS Extension, Charlotte County
Invert Trivia: What group of invertebrate species shares these
three distinctive features? 1) A body with five-part symmetry;
2) an internal skeleton made of calcium carbonate; and 3) a
water vascular system of fluid-filled vessels that manifests to
the outer surface as structures called tube feet. Stumped?
Here’s a few more clues. This group of species are entirely
marine, and they lack a head, heart, brain and eyes. They have
separate sexes but it’s generally impossible to tell them apart
based on their outward appearance. And, they can regenerate
body parts.
These awesome creatures can only be echinoderms. In Greek,
echino means spiny, and derma refers to skin, and these spinyskinned creatures comprise sea urchins, sea cucumbers, feather
stars, sea stars, and brittle stars. Echinoderms have an ancient
lineage that dates back at least 600 million years. Today, at
least 6,500 species are recognized within six living classes which
are highlighted below.
Sea Stars: (~1,800 species) Also known as starfish, consist of a
central disk and five or more projecting arms. Sea stars may be
predators; scavengers; deposit feeders (ingest mud and extract
food particles; or suspension feeders (extract prey and food
particles from the water). Some sea stars give ‘going out to
dinner’ a
whole new
meaning in
that they have
the ability to
extrude their
stomach into
very small
Red spined (aka coni- Striped (aka lined) sea openings to
cal spined) sea star,
star, Luidia clathrata
consume prey.
Echinaster sentus juvenile
Feather Stars: (~700 species) they have five or more (usually at
least 10) arms that are feathery in appearance. These ‘feathers’
are called pinnules and serve as food-gathering organs. Feather
stars typically feed at night and are seldom seen, hence no
photo!
Brittle Stars and Basket Stars: (~2,000 species) they owe their
name to their ability to voluntarily break their arms, which they
EAS-102516-005
do to avoid
predation.
They also are
able to cast off
their central
disk,
discarding
their stomach,
Brittle star OphiBanded-arm brittle
gonads, and
ophragmus filograstar, Ophioderma
other tissues,
neus
appressum
AND then
regenerate
these parts in two weeks to two months. Basket stars are not
often seen. They resemble brittle stars but with branching arms.
Sea Urchins:
(~900 species)
Sea urchins can
be ‘regular’ like
the round spiny
ones we
typically see, or
‘irregular’ like
our sand dollars Test (skeletal remains)
and sea biscuits. of an inflated sea bisRegular urchins cuit, Clypeaster
and sand dollars rosaceus
are herbivores
and have five triangular shaped teeth
for grinding called the Aristotle’s
lantern. Sea biscuits are detritivores.
They eat sediments and extract their
food from it. Urchins are host to a wide
variety of parasites and beneficial
organisms. Bizarre and kind of gross,
one species of crab lives only in the
rectum of sea urchins.
Five keyhole sand
dollar, Mellita quinquiesperforata
Variegated urchin,
Lytechinus variegatus showing its triangular teeth
Sea Cucumbers: (~1,200 species) Last
but not least, sea cucumbers are so
absolutely awesome! Their mouth is surrounded by 10-30
feeding tentacles, which are actually modified tube feet. Sea
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SEA STARS, SEA CUCUMBERS, SEA URCHINS AND MORE…
October 25, 2016
cucumber
have the
ability to eject
a toxic sticky
substance
when
threatened.
They can also
Three-rowed (aka
Florida sea cucumber,
eject their
chocolate
chip)
sea
Holothuria floridana
intestines and
cucumber,
Isoother organs,
which they do stichopus badionotus
to confuse
predators. These organs are quickly regenerated.
So that was only five classes right? Well the fairly recently
discovered sea daisies, with 2 known living species appear to
live exclusively on pieces of wood on the deep sea floor.
Want to collect echinoderms in Florida? Know the rules!
Generally if it’s dead its fair game, although not always in state
and federal parks. If it’s alive, echinoderms fall under FWC’s
Marine Life regulations. Collection of some species, like the
cushion sea star or long-spined urchin is prohibited. For other
species, there is a bag limit, and in most cases there are gear
and holding requirements. In all cases a valid saltwater fishing
license is required. In Manatee County, collection is limited to
only two per
person per
day. And, in
Lee County
all collection
of
echinoderms
is
Cushion (aka BahaLong-spined urchin,
prohibited.
mian) sea star,
Diadema antillarum
Oreaster reticulatus
Sources:
FWC Fishing Regulations: http://myfwc.com/fishing/saltwater/recreational/
Hendler, G., J.E. Miller, D.L. Pawson, and P.M. Kier. 1995. Sea Stars, Sea Urchins, and Allies: Echinoderms of Florida and the Caribbean, Smithsonian Institution Press, Washington and London. 390pp.
Humann, P. and N. Deloach. 2002. Reef Creature Identification: Florida Caribbean Bahamas, 2nd Edition, New World Publications,
Inc., Jacksonville, FL. 420pp.
All photos Florida Sea Grant
BETTY STAUGLER
Florida Sea Grant Agent
[email protected]
UF/IFAS EXTENSION, CHARLOTTE COUNTY
25550 Harbor View Road, Suite 3 - Port Charlotte, Florida 33980
941.764.4340 - 941.764.4343 (fax) - http://charlotte.ifas.ufl.edu