Echinoderm - Wikipedia

Echinoderm - Wikipedia
Jump to content
From Wikipedia, the free encyclopedia
Marine phylum of animals often with radial symmetries
For the fungus, see
Echinoderma
Echinoderms
Temporal range:
Cambrian Stage 3
Present
PreꞒ
Pg
Extant and extinct echinoderms of six classes:
Fromia indica
Asteroidea
);
Ophiocoma scolopendrina
Ophiuroidea
);
Stomopneustes variolaris
Echinoidea
);
Oxycomanthus bennetti
Crinoidea
);
Actinopyga echinites
Holothuroidea
);
Ctenocystis
Ctenocystoidea
).
Scientific classification
Kingdom:
Animalia
Subkingdom:
Eumetazoa
Clade
ParaHoxozoa
Clade
Bilateria
Clade
Nephrozoa
Superphylum:
Deuterostomia
Clade
Ambulacraria
Phylum:
Echinodermata
Bruguière, 1791 [ex
Klein
, 1734]
Type genus
Echinus
Linnaeus, 1758
Subphyla and classes
See
taxonomy
An
echinoderm
aɪ
ɜːr
-/
is any
animal
of the
phylum
Echinodermata
aɪ
oʊ
ɜːr
), which includes
starfish
brittle stars
sea urchins
sand dollars
and
sea cucumbers
, as well as the sessile
sea lilies
or "stone lilies".
While
bilaterally symmetrical
as
larvae
, as
adults
echinoderms are recognisable by their usually five-pointed
radial symmetry
(pentamerous symmetry), and are found on the sea bed at every ocean depth from the
intertidal zone
to the
abyssal zone
. The phylum contains about 7,600 living
species
, making it the second-largest group of
deuterostomes
after the
chordates
, as well as the largest
marine-only
phylum. The first definitive echinoderms appeared near the start of the
Cambrian
Echinoderms are important both ecologically and geologically. Ecologically, there are few other groupings so abundant in the
deep sea
, as well as
shallower oceans
. Most echinoderms are able to
reproduce asexually
and
regenerate
tissue, organs and limbs; in some cases, they can undergo complete regeneration from a single limb. Geologically, the value of echinoderms is in their
ossified
dermal
endoskeletons
, which are major contributors to many
limestone
formations and can provide valuable clues as to the geological environment. They were the most used species in regenerative research in the 19th and 20th centuries. Further, some scientists hold that the
radiation
of echinoderms was responsible for the
Mesozoic Marine Revolution
Etymology
edit
The name echinoderm is from
Ancient Greek
ἐχῖνος
ekhînos
hedgehog
and
δέρμα
dérma
skin
The name Echinodermata was originated by
Jacob Theodor Klein
in 1734, but only in reference to
echinoids
. It was expanded to the phylum level by
Jean Guillaume Bruguière
, first informally in 1789 and then in formal Latin in 1791. In 1955,
Libbie Hyman
attributed the name to "Bruguière, 1791 [ex Klein, 1734]."
This attribution has become common and is listed by the
Integrated Taxonomic Information System
(ITIS),
although some workers believe that the ITIS rules should result in attributing "Klein, 1778" due to a 2nd edition of his work published by
Leske
in that year.
While Echinodermata has been in common use since the mid-1800s,
several other names had been proposed.
Notably,
Francis Arthur Bather
called the phylum "Echinoderma" (apparently after
Latreille
, 1825
) in his 1900 treatise on the phylum,
but this name now refers to a
fungus
Diversity
edit
There are about 7,600
extant
species of echinoderm as well as about 13,000 known extinct species.
10
All echinoderms are
marine
, but they are found in habitats ranging from shallow intertidal areas to abyssal depths. Five extant classes of echinoderms are generally recognized: the Asteroidea (
starfish
, with over 1900 species), Ophiuroidea (
brittle stars
, with around 2,300 species), Echinoidea (
sea urchins
and
sand dollars
, with some 900 species), Holothuroidea (
sea cucumbers
, with about 1,430 species), and Crinoidea (
feather stars
and
sea lilies
, with around 580 species).
11
12
The extant classes of echinoderms
A brittle star,
Ophionereis reticulata
sea cucumber
Stichopus chloronotus
, from Malaysia
Starfish of varied colours
A sea urchin,
Strongylocentrotus purpuratus
Crinoid
on a
coral reef
Anatomy and physiology
edit
Echinoderms evolved from animals with
bilateral symmetry
. Although adult echinoderms possess
pentaradial
symmetry, their larvae are
ciliated
, free-swimming organisms with bilateral symmetry. Later, during metamorphosis, the left side of the body grows at the expense of the right side, which is eventually absorbed. The left side then grows in a
pentaradially
symmetric fashion, in which the body is arranged in five parts around a central axis.
13
Within the
Asterozoa
, there are a few exceptions from the rule. Most starfish in the genus
Leptasterias
have six arms, although five-armed individuals can occur. The
Brisingida
also contain some six-armed species. Amongst the brittle stars, six-armed species such as
Ophiothela danae
Ophiactis savignyi
, and
Ophionotus hexactis
exist, and
Ophiacantha vivipara
often has more than six.
14
Echinoderms have secondary radial symmetry in portions of their body at some stage of life, most likely an adaptation to a sessile or slow-moving existence.
15
Many crinoids and some seastars are symmetrical in multiples of the basic five; starfish such as
Labidiaster annulatus
possess up to fifty arms, while the
sea-lily
Comaster schlegelii
has two hundred.
16
Genetic studies have shown that genes directing anterior-most development are expressed along ambulacra in the center of starfish rays, with the next-most-anterior genes expressed in the surrounding fringe of tube feet. Genes related to the beginning of the trunk are expressed at the ray margins, but trunk genes are only expressed in interior tissue rather than on the body surface. This means that a starfish body can more-or-less be considered to consist only of a head.
17
18
Skin and skeleton
edit
Echinoderms have a
mesodermal
skeleton in the dermis, composed of
calcite
-based plates known as
ossicles
. If solid, these would form a heavy skeleton, so they have a sponge-like porous structure known as stereom.
19
20
Ossicles may be fused together, as in the
test
of sea urchins, or may
articulate
to form flexible joints as in the arms of sea stars, brittle stars and crinoids. The ossicles may bear external projections in the form of spines, granules or warts and they are supported by a tough
epidermis
. Skeletal elements are sometimes deployed in specialized ways, such as the chewing organ called "
Aristotle's lantern
" in sea urchins, the supportive stalks of crinoids, and the structural "lime ring" of sea cucumbers.
13
Although individual ossicles are robust and fossilize readily, complete skeletons of starfish, brittle stars and crinoids are rare in the fossil record. On the other hand, sea urchins are often well preserved in chalk beds or limestone. During fossilization, the cavities in the stereom are filled in with calcite that is continuous with the surrounding rock. On fracturing such rock,
paleontologists
can observe distinctive cleavage patterns and sometimes even the intricate internal and external structure of the test.
21
The epidermis contains pigment cells that provide the often vivid colours of echinoderms, which include deep red, stripes of black and white, and intense purple.
22
These cells may be light-sensitive, causing many echinoderms to change appearance completely as night falls. The reaction can happen quickly: the sea urchin
Centrostephanus longispinus
changes colour in just fifty minutes when exposed to light.
23
One characteristic of most echinoderms is a special kind of tissue known as
catch connective tissue
. This
collagen
-based material can change its mechanical properties under nervous control rather than by muscular means. This tissue enables a starfish to go from moving flexibly around the seabed to becoming rigid while prying open a
bivalve mollusc
or preventing itself from being extracted from a crevice. Similarly, sea urchins can lock their normally mobile spines upright as a defensive mechanism when attacked.
24
25
The water vascular system
edit
Main article:
Water vascular system
Diagram of
water vascular system
of a starfish, showing the ring canal, the radial canals, ampullae (small bulbs), and
tube feet
Echinoderms possess a unique water vascular system, a network of fluid-filled canals modified from the
coelom
(body cavity) that function in gas exchange, feeding, sensory reception and locomotion. This system varies between different classes of echinoderm but typically opens to the exterior through a sieve-like
madreporite
on the aboral (upper) surface of the animal. The madreporite is linked to a slender duct, the stone canal, which extends to a ring canal that encircles the mouth or
oesophagus
. The ring canal branches into a set of radial canals, which in asteroids extend along the arms, and in echinoids adjoin the test in the ambulacral areas. Short lateral canals branch off the radial canals, each one ending in an ampulla. Part of the ampulla can protrude through a pore (or a pair of pores in sea urchins) to the exterior, forming a podium or
tube foot
. The water vascular system assists with the distribution of nutrients throughout the animal's body; it is most visible in the tube feet which can be extended or contracted by the redistribution of fluid between the foot and the internal ampulla.
26
27
The organisation of the water vascular system is somewhat different in ophiuroids, where the madreporite may be on the oral surface and the podia lack suckers.
28
In holothuroids, the system is reduced, often with few tube feet other than the specialised feeding tentacles, and the madreporite opens on to the coelom. Some holothuroids like the Apodida lack tube feet and canals along the body; others have longitudinal canals.
29
The arrangement in crinoids is similar to that in asteroids, but the tube feet lack suckers and are used in a back-and-forth wafting motion to pass food particles captured by the arms towards the central mouth. In the asteroids, the same motion is employed to move the animal across the ground.
30
Other organs
edit
Echinoderms possess a simple digestive system which varies according to the animal's diet. Starfish are mostly carnivorous and have a mouth, oesophagus, two-part stomach, intestine and rectum, with the anus located in the centre of the aboral body surface. With a few exceptions, the members of the order
Paxillosida
do not possess an anus.
31
32
In many species of starfish, the large cardiac stomach can be everted to digest food outside the body. Some other species are able to ingest whole food items such as
molluscs
33
Brittle stars, which have varying diets, have a blind gut with no intestine or anus; they expel
food waste
through their mouth.
34
Sea urchins are herbivores and use their specialised mouthparts to graze, tear and chew their food, mainly
algae
. They have an oesophagus, a large stomach and a rectum with the anus at the apex of the test.
35
Sea cucumbers are mostly
detritivores
, sorting through the sediment with modified tube feet around their mouth, the buccal tentacles. Sand and mud accompanies their food through their simple gut, which has a long coiled intestine and a large
cloaca
36
Crinoids are
suspension feeders
, passively catching
plankton
which drift into their outstretched arms. Boluses of mucus-trapped food are passed to the mouth, which is linked to the anus by a loop consisting of a short oesophagus and longer intestine.
37
The
coelomic cavities
of echinoderms are complex. Aside from the water vascular system, echinoderms have a
haemal coelom
, a peri
visceral
coelom, a
gonadal
coelom and often also a perihaemal coelom.
38
During development, echinoderm coelom is divided into the metacoel, mesocoel and protocoel (also called somatocoel, hydrocoel and axocoel, respectively).
39
The water vascular system, haemal system and perihaemal system form the tubular coelomic system.
40
Echinoderms are unusual in having both a coelomic circulatory system (the water vascular system) and a haemal circulatory system, as most groups of animals have just one of the two.
41
Haemal and perihaemal systems are derived from the original coelom, forming an
open
and reduced circulatory system. This usually consists of a central ring and five radial vessels. There is no true
heart
, and the blood often lacks any respiratory pigment. Gaseous exchange occurs via dermal branchiae or papulae in starfish, genital bursae in brittle stars, peristomial gills in sea urchins and cloacal trees in sea cucumbers. Exchange of gases also takes place through the tube feet. Echinoderms lack specialized excretory (waste disposal) organs and so
nitrogenous waste
, chiefly in the form of
ammonia
, diffuses out through the respiratory surfaces.
42
The coelomic fluid contains the
coelomocytes
, or immune cells. There are several types of immune cells, which vary among classes and species. All classes possess a type of
phagocytic
amebocyte, which engulf invading particles and infected cells, aggregate or clot, and may be involved in
cytotoxicity
. These cells are usually large and granular, and are believed to be a main line of defence against potential pathogens.
43
Depending on the class, echinoderms may have
spherule
cells (for cytotoxicity, inflammation, and anti-bacterial activity), vibratile cells (for coelomic fluid movement and clotting), and crystal cells (which may serve for
osmoregulation
in sea cucumbers).
43
44
The coelomocytes secrete
antimicrobial peptides
against bacteria, and have a set of
lectins
and
complement proteins
as part of an
innate immune system
that is still being characterised.
45
Echinoderms have a simple radial
nervous system
that consists of a modified
nerve net
of interconnected neurons with no central
brain
, although some do possess
ganglia
. Nerves radiate from central rings around the mouth into each arm or along the body wall; the branches of these nerves coordinate the movements of the organism and the synchronisation of the tube feet. Starfish have sensory cells in the epithelium and have simple
eyespots
and touch-sensitive tentacle-like tube feet at the tips of their arms. Sea urchins have no particular sense organs but do have
statocysts
that assist in gravitational orientation, and they too have sensory cells in their epidermis, particularly in the tube feet, spines and
pedicellariae
. Brittle stars, crinoids and sea cucumbers in general do not have sensory organs, but some burrowing sea cucumbers of the
order
Apodida
have a single statocyst adjoining each radial nerve, and some have an eyespot at the base of each tentacle.
46
The
gonads
at least periodically occupy much of the body cavities of sea urchins
47
and sea cucumbers, while the less voluminous crinoids, brittle stars and starfish have two gonads in each arm. While the ancestors of modern echinoderms are believed to have had one genital aperture, many organisms have multiple
gonopores
through which eggs or sperm may be released.
48
Regeneration
edit
Further information:
Starfish regeneration
Sunflower star
regenerating several arms
Many echinoderms have great powers of
regeneration
. Many species routinely
autotomize
and regenerate arms and
viscera
. Sea cucumbers often discharge parts of their internal organs if they perceive themselves to be threatened, regenerating them over the course of several months. Sea urchins constantly replace spines lost through damage, while sea stars and sea lilies readily lose and regenerate their arms. In most cases, a single severed arm cannot grow into a new starfish in the absence of at least part of the disc.
49
50
51
52
However, in a few species a single arm can survive and develop into a complete individual, and arms are sometimes intentionally detached for the purpose of
asexual reproduction
50
51
52
During periods when they have lost their digestive tracts, sea cucumbers live off stored nutrients and absorb dissolved organic matter directly from the water.
53
The regeneration of lost parts involves both
epimorphosis
and
morphallaxis
. In epimorphosis
stem cells
, either from a reserve pool or those produced by
dedifferentiation
, form a
blastema
and generate new tissues. Morphallactic regeneration involves the movement and remodelling of existing tissues to replace lost parts.
54
Direct
transdifferentiation
of one type of tissue to another during tissue replacement is also observed.
55
Reproduction
edit
Sexual reproduction
edit
Echinoderms become sexually mature after approximately two to three years, depending on the species and the environmental conditions. Almost all species have separate
male and female sexes
, though some are
hermaphroditic
. The eggs and sperm cells are typically released into open water, where fertilisation takes place. The release of sperm and eggs is synchronised in some species, usually with regard to the lunar cycle. In other species, individuals may aggregate during the reproductive season, increasing the likelihood of successful fertilisation. Internal fertilisation has been observed in three species of sea star, three brittle stars and a deep-water sea cucumber. Even at
abyssal depths
, where no light penetrates, echinoderms often synchronise their reproductive activity.
56
Some echinoderms
brood their eggs
. This is especially common in cold water species where planktonic larvae might not be able to find sufficient food. These retained eggs are usually few in number and are supplied with large yolks to nourish the developing embryos. In starfish, the female may carry the eggs in special pouches, under her arms, under her arched body, or even in her cardiac stomach.
57
Many brittle stars are hermaphrodites; they often brood their eggs, usually in special chambers on their oral surfaces, but sometimes in the ovary or coelom.
58
In these starfish and brittle stars, development is usually direct to the adult form, without passing through a bilateral larval stage.
59
A few sea urchins and one species of sand dollar carry their eggs in cavities, or near their anus, holding them in place with their spines.
60
Some sea cucumbers use their buccal tentacles to transfer their eggs to their underside or back, where they are retained. In a very small number of species, the eggs are retained in the coelom where they develop
viviparously
, later emerging through ruptures in the body wall.
61
In some crinoids, the embryos develop in special breeding bags, where the eggs are held until sperm released by a male happens to find them.
62
Asexual reproduction
edit
See also:
§ Regeneration
'Comet' form of
Linckia
One species of
seastar
Ophidiaster granifer
, reproduces asexually by
parthenogenesis
63
In certain other
asterozoans
, adults reproduce asexually until they mature, then reproduce sexually. In most of these species, asexual reproduction is by
transverse fission
with the disc splitting in two. Both the lost disc area and the missing arms regrow, so an individual may have arms of varying lengths.
52
64
During the period of regrowth, they have a few tiny arms and one large arm, and are thus often known as "comets".
51
65
Adult sea cucumbers reproduce asexually by transverse fission.
Holothuria parvula
uses this method frequently, splitting into two a little in front of the midpoint. The two halves each regenerate their missing organs over a period of several months, but the missing genital organs are often very slow to develop.
66
The larvae of some echinoderms are capable of asexual reproduction. This has long been known to occur among starfish and brittle stars, but has more recently been observed in a sea cucumber, a sand dollar and a sea urchin.
67
This may be by
autotomising
parts that develop into secondary larvae, by
budding
, or by
splitting transversely
. Autotomised parts or buds may develop directly into fully formed larvae, or may pass through a
gastrula
or even a
blastula
stage. New larvae can develop from the preoral hood (a mound like structure above the mouth), the side body wall, the postero-lateral arms, or their rear ends.
67
68
69
Cloning is costly to the larva both in resources and in development time. Larvae undergo this process when food is plentiful
70
or temperature conditions are optimal.
69
Cloning may occur to make use of the tissues that are normally lost during metamorphosis.
71
The larvae of some sand dollars clone themselves when they detect dissolved fish mucus, indicating the presence of predators.
69
71
Asexual reproduction produces many smaller larvae that escape better from planktivorous fish, implying that the mechanism may be an anti-predator adaptation.
72
Larval development
edit
bilaterally symmetric
echino
pluteus larva
with larval arms
Development begins with a bilaterally symmetrical embryo, with a coeloblastula developing first.
Gastrulation
marks the opening of the "second mouth" that places echinoderms within the deuterostomes, and the mesoderm, which will host the skeleton, migrates inwards. The secondary body cavity, the coelom, forms by the partitioning of three body cavities. The larvae are often
planktonic
, but in some species the eggs are retained inside the female, while in some the female broods the larvae.
73
74
The larvae pass through several stages, which have specific names derived from the taxonomic names of the adults or from their appearance. For example, a sea urchin has an 'echinopluteus' larva while a brittle star has an 'ophiopluteus' larva. A starfish has a '
bipinnaria
' larva, which develops into a multi-armed '
brachiolaria
' larva. A sea cucumber's larva is an 'auricularia' while a crinoid's is a 'vitellaria'. All these larvae are
bilaterally symmetrical
and have bands of cilia with which they swim; some, usually known as 'pluteus' larvae, have arms. When fully developed, they settle on the seabed to undergo metamorphosis, and the larval arms and gut degenerate. The left-hand side of the larva develops into the oral surface of the juvenile, while the right side becomes the aboral surface. At this stage, the pentaradial symmetry develops.
75
76
plankton-eating
larva, living and feeding in the water column, is considered to be the ancestral larval type for echinoderms, but in extant echinoderms, some 68% of species develop using a
yolk-feeding
larva.
11
The provision of a yolk-sac means that smaller numbers of eggs are produced, the larvae have a shorter development period and a smaller dispersal potential, but a greater chance of survival.
11
Distribution and habitat
edit
Echinoderms are globally distributed in almost all depths, latitudes and environments in the ocean. Living echinoderms are known from between 0 to over 10,000 meters. Adults are mainly
benthic
, living on the seabed, whereas larvae are often
pelagic
, living as plankton in the open ocean. Some holothuroid adults such as
Pelagothuria
are pelagic.
77
In the fossil record, some crinoids were pseudo-planktonic, attaching themselves to floating logs and debris. Some Paleozoic taxa displayed this life mode, before competition from organisms such as barnacles restricted the extent of the behaviour.
78
Mode of life
edit
Locomotion
edit
Echinoderms use their tube feet to move about. (
Colobocentrotus atratus
shown)
Further information:
Animal locomotion
Echinoderms primarily use their tube feet to move about, though some sea urchins also use their spines. The tube feet typically have a tip shaped like a suction pad in which a vacuum can be created by contraction of muscles. This combines with some stickiness from the secretion of
mucus
to provide adhesion. The tube feet contract and relax in waves which move along the adherent surface, and the animal moves slowly along.
79
Brittle stars are the most agile of the echinoderms. Any one of the arms can form the axis of symmetry, pointing either forwards or back. The animal then moves in a co-ordinated way, propelled by the other four arms. During locomotion, the propelling arms can made either snake-like or rowing movements.
80
Starfish move using their tube feet, keeping their arms almost still, including in genera like
Pycnopodia
where the arms are flexible. The oral surface is covered with thousands of tube feet which move out of time with each other, but not in a
metachronal rhythm
; in some way, however, the tube feet are coordinated, as the animal glides steadily along.
81
Some burrowing starfish have points rather than suckers on their tube feet and they are able to "glide" across the seabed at a faster rate.
82
Sea urchins use their tube feet to move around in a similar way to starfish. Some also use their articulated spines to push or lever themselves along or lift their oral surfaces off the substrate. If a sea urchin is overturned, it can extend its tube feet in one ambulacral area far enough to bring them within reach of the substrate and then successively attach feet from the adjoining area until it is righted. Some species bore into rock, usually by grinding away at the surface with their mouthparts.
83
Sea cucumbers like this
Neothyonidium magnum
can burrow using peristaltic movements.
Most sea cucumber species move on the surface of the seabed or burrow through sand or mud using
peristaltic
movements; some have short tube feet on their under surface with which they can creep along in the manner of a starfish. Some species drag themselves along using their buccal tentacles, while others manage to swim with peristaltic movements or rhythmic flexing. Many live in cracks, hollows and burrows and hardly move at all. Some deep-water species are
pelagic
and can float in the water with webbed papillae forming sails or fins.
84
The majority of feather stars (also called Comatulida or "unstalked crinoids") and some stalked forms are motile. Several stalked crinoid species are sessile, attached permanently to the substratum. Movement in most sea lilies is limited to bending (their stems can bend) and rolling and unrolling their arms; a few species can relocate themselves on the seabed by crawling. Feather stars are unattached and usually live in crevices, under corals or inside sponges with their arms the only visible part. Some feather stars emerge at night and perch themselves on nearby eminences to better exploit food-bearing currents. Many species can "walk" across the seabed, raising their body with the help of their arms, or swim using their arms. Most species of feather stars, however, are largely sedentary, seldom moving far from their chosen place of concealment.
85
Feeding
edit
The modes of feeding vary greatly between the different echinoderm taxa. Crinoids and some brittle stars tend to be passive filter-feeders,
86
87
enmeshing suspended particles from passing water. Most sea urchins are grazers;
88
sea cucumbers are deposit feeders;
89
and the majority of starfish are active hunters.
90
Crinoids catch food particles using the tube feet on their outspread pinnules, move them into the ambulacral grooves, wrap them in mucus, and convey them to the mouth using the cilia lining the grooves.
86
The exact dietary requirements of crinoids have been little researched, but in the laboratory, they can be fed with diatoms.
91
Basket stars
are suspension feeders, raising their branched arms to collect
zooplankton
, while other brittle stars use several methods of feeding. Some are suspension feeders, securing food particles with mucus strands, spines or tube feet on their raised arms. Others are scavengers and detritus feeders. Others again are voracious
carnivores
and able to lasso their waterborne prey with a sudden encirclement by their flexible arms. The limbs then bend under the disc to transfer the food to the jaws and mouth.
92
Many sea urchins feed on algae, often scraping off the thin layer of algae covering the surfaces of rocks with their specialised mouthparts known as Aristotle's lantern. Other species devour smaller organisms, which they may catch with their tube feet. They may also feed on dead fish and other animal matter.
88
Sand dollars may perform suspension feeding and feed on
phytoplankton
, detritus, algal pieces and the bacterial layer surrounding grains of sand.
93
Sea cucumbers are often mobile deposit or suspension feeders, using their buccal podia to actively capture food and then stuffing the particles individually into their buccal cavities. Others ingest large quantities of sediment, absorb the organic matter and pass the indigestible mineral particles through their guts. In this way they disturb and process large volumes of substrate, often leaving characteristic ridges of sediment on the seabed. Some sea cucumbers live infaunally in burrows, anterior-end down and anus on the surface, swallowing sediment and passing it through their gut. Other burrowers live anterior-end up and wait for detritus to fall into the entrances of the burrows or rake in debris from the surface nearby with their buccal podia.
94
Nearly all starfish are detritus feeders or carnivores, though a few are suspension feeders. Small fish landing on the upper surface may be captured by
pedicellariae
and dead animal matter may be scavenged but the main prey items are living invertebrates, mostly bivalve molluscs. To feed on one of these, the starfish moves over it, attaches its tube feet and exerts pressure on the valves by arching its back. When a small gap between the valves is formed, the starfish inserts part of its stomach into the prey, excretes digestive
enzymes
and slowly liquefies the soft body parts. As the
adductor muscle
of the bivalve relaxes, more stomach is inserted and when digestion is complete, the stomach is returned to its usual position in the starfish with its now liquefied bivalve meal inside it. Other starfish evert the stomach to feed on sponges, sea anemones, corals, detritus and algal films.
95
Antipredator defence
edit
Many echinoderms, like this
Centrostephanus coronatus
, are defended by sharp spines.
Despite their low nutrition value and the abundance of indigestible calcite, echinoderms are preyed upon by many organisms, including
bony fish
sharks
eider ducks
gulls
crabs
gastropod molluscs
, other echinoderms,
sea otters
Arctic foxes
and humans. Larger starfish prey on smaller ones; the great quantity of eggs and larva that they produce form part of the
zooplankton
, consumed by many marine creatures. Crinoids, on the other hand, are relatively free from predation.
96
Antipredator defences
include the presence of spines, toxins (inherent or delivered through the tube feet), and the discharge of sticky entangling threads by sea cucumbers. Although most echinoderm spines are blunt, those of the
crown-of-thorns starfish
are long and sharp and can cause a painful puncture wound as the epithelium covering them contains a toxin.
97
Because of their catch connective tissue, which can change rapidly from a flaccid to a rigid state, echinoderms are very difficult to dislodge from crevices. Some sea cucumbers have a cluster of
cuvierian tubules
which can be ejected as long sticky threads from their anus to entangle and permanently disable an attacker. Sea cucumbers occasionally defend themselves by rupturing their body wall and discharging the gut and internal organs.
98
Starfish and brittle stars may undergo
autotomy
when attacked, detaching an arm; this may distract the predator for long enough for the animal to escape. Some starfish species can swim away from danger.
99
Ecology
edit
A blue
Linckia
starfish on a
coral reef
, a biodiverse ecosystem
Echinoderms are numerous invertebrates whose adults play an important role in benthic
ecosystems
, while the larvae are a major component of the plankton. Among the ecological roles of adults are the grazing of sea urchins, the sediment processing of heart urchins, and the suspension and deposit feeding of crinoids and sea cucumbers.
11
100
Some sea urchins can bore into solid rock, destabilising rock faces and releasing nutrients into the ocean. Coral reefs are also bored into in this way, but the rate of accretion of carbonate material is often greater than the erosion produced by the sea urchin.
101
Echinoderms sequester about 0.1 gigatonnes of carbon dioxide per year as
calcium carbonate
, making them important contributors in the global
carbon cycle
102
Echinoderms sometimes have large population swings which can transform ecosystems. In 1983, for example, the mass mortality of the tropical sea urchin
Diadema antillarum
in the Caribbean caused a change from a coral-dominated reef system to an alga-dominated one.
103
Sea urchins are among the main herbivores on reefs and there is usually a fine balance between the urchins and the kelp and other algae on which they graze. A diminution of the numbers of predators (otters, lobsters and fish) can result in an increase in urchin numbers, causing
overgrazing
of
kelp forests
, resulting in an alga-denuded "
urchin barren
".
104
On the
Great Barrier Reef
, an unexplained increase in the numbers of
crown-of-thorns starfish
Acanthaster planci
), which graze on living coral tissue, has greatly increased coral mortality and reduced coral reef
biodiversity
105
Taxonomy and evolution
edit
See also:
List of echinoderm orders
The characteristics of adult echinoderms are the possession of a
water vascular system
with external
tube feet
and a
stereom
endoskeleton.
Stereom is a
calcareous
material consisting of
ossicles
connected by a mesh of
collagen
fibres, which is unique to this phylum.
Phylogeny
edit
Echinoderm phylogeny has long been a contentious subject. While the relationships among extant taxa are well-understood, there is no broadly accepted consensus regarding the phylum's origins or the relationships among its extinct groups.
106
107
108
Echinoderm evolution shows a high degree of
homoplasy
, meaning that many features have evolved multiple times independently. This means that many features initially assumed to indicate a genetic connection do not, in fact, do so, which has obscured the true relationships of various groups.
109
External phylogeny
edit
Echinoderms are
bilaterians
, meaning that their ancestors were mirror-symmetric, as their larvae remain. Among the bilaterians, they belong to the
deuterostome
division, meaning that the
blastopore
, the first opening to form during embryo development, becomes the
anus
instead of the mouth.
110
111
Echinoderms are the sister group of the
Hemichordata
, with which they form the crown group
Ambulacraria
112
Two extinct taxa of uncertain placement,
Vetulocystida
and
Yanjiahella
, have each been proposed as either stem-group echinoderms
113
114
or stem-group ambulacrarians.
115
116
Vetulocystids have also been proposed as stem-group
chordates
117
while
Yanjiahella
has also been proposed to be a stem-group hemichordate.
116
The Ambulacrarian context of the echinoderms is shown below, simplified from Li et al. 2023,
118
with the possible ambulacrarian placements of the uncertain taxa shown with dashed lines and question marks:
Ambulacraria
Vetulocystida
Cambroernida
Yanjiahella
Ambulacraria
Echinodermata
? Vetulocystida†
Yanjiahella
Echinodermata
crownward
total group
Hemichordata
Yanjiahella
Hemichordata
crownward
total group
crown group
total group
Internal phylogeny: extant classes
edit
The extant echinoderms consist of the
Crinoidea
and the
Eleutherozoa
, the latter of which is divided into the
Asterozoa
and the
Echinozoa
119
120
Echinodermata
Crinoidea
sea lillies and feather stars
Eleutherozoa
Echinozoa
Holothuroidea
sea cucumbers
Echinoidea
sea urchins, etc
Asterozoa
Ophiuroidea
brittle and basket stars
Asteroidea
sea stars
Internal phylogeny: total group
edit
The lack of a consensus
cladistic
phylogeny incorporating extinct echinoderm groups has resulted in the continued use of terms from
Linnaean taxonomies
, even when the named taxa are known to be
paraphyletic
and/or
polyphyletic
Linnaean taxonomies
edit
Three taxonomies introduced nearly all of the traditional subphyla and class divisions that continue to be referenced in cladistic work:
F. A. Bather
produced the earliest widely referenced classification of both fossil and extant echinoderms in 1900, using a two-subphylum system.
121
In 1966, the
Treatise on Invertebrate Paleontology
, rejected Bather's classification, replacing it with a new four-subphylum scheme
122
that had been previously proposed by
H. B. Fell
123
James Sprinkle added a fifth subphylum to the
Treatise
taxonomy in 1973.
124
His later class-level taxonomy of the five subphyla was the most recent approach cited in an early cladistic re-assessment of the phylum.
125
Notable Linnaean taxonomies of the phylum Echinodermata
Bather, 1900
126
Moore (ed.), 1966–7
127
128
Sprinkle, 1980
129
130
Phylum
Echinoderma
Latreille, 1825
131
Subphylum
Pelmatozoa
Leuckart, 1848
Class
Cystidea†
von Buch, 1844
Class
Blastoidea
Say, 1825
sensu extenso
Class
Crinoidea
Miller, 1821
Class
Edrioasteroidea
E. Billings, 1854–58; Huxley, 1877; Bather, 1899
Subphylum
Eleutherozoa
Bell, 1891
Class
Holothuroidea
C. T. v. Siebold, 1848
Class
Stelleroidea
Gregory, 1900
Class
Echinoidea
Leske
, 1778
Phylum
Echinodermata
Klein, 1734; Brugière, 1789
Subphylum
Homalozoa
Whitehouse, 1941
Class
Stylophora
Gill & Caster, 1960
Class
Homostelea
Gill & Caster, 1960
Class
Homoiostelea
Gill & Caster, 1960
Subphylum
Crinozoa
Matsumoto, 1929
Class
Lepidocystoidea
Durham, 1967
Class
Eocrinoidea
Jaekel, 1918
Class
Cystoidea
von Buch, 1846
Class
Edrioblastoidea†
Fay, 1962
Class
Parablastoidea†
Hudson, 1907
Class
Blastoidea
Say, 1825
Class
Paracrinoidea
Regnéll, 1945
Class
Crinoidea
Miller, 1821
Subphylum
Asterozoa
Zittel 1895
Class
Stelleroidea
Lamarck 1816
Subphylum
Echinozoa
Haekel  Zittel 1895
Class
Helicoplacoidea
Durham & Caster, 1963
Class
Camptostromatoidea
Durham, 1966
Class
Edrioasteroidea
Billings, 1858
Class
Cyclocystoidea†
Miller & Gurley, 1895
Class
Ophiocistioidea
Solas, 1899
Class
Echinoidea
Leske, 1778
Class
Holothuroidea
de Blainville, 1834
Phylum
Echinodermata
de Bruguière
[sic]
, 1791
Subphylum
Homalozoa
Whitehouse, 1941
Class
Ctenocystoidea
Robinson & Sprinkle, 1969
Class
Stylophora
Gill & Caster, 1960
Class
Homostelea
Gill & Caster, 1960
Class
Homoiostelea
Gill & Caster, 1960
Subphylum
Blastozoa
Sprinkle, 1973
Class
Eocrinoidea
Jaekel, 1918
Class
Rhombifera
Zittel, 1879
Class
Diploporita
Müller, 1854
Class
Parablastoidea†
Hudson, 1907
Class
Blastoidea
Say, 1825
Subphylum
Crinozoa
Matsumoto, 1929, restricted in Sprinkle, 1973
Class
Paracrinoidea
Regnéll, 1945
Class
Crinoidea
Miller, 1821
Subphylum
Asterozoa
Zittel 1895
Class
Asteroidea
de Blainville, 1830
Class
Ophiuroidea
Gray, 1840
Subphylum
Echinozoa
Haekel  Zittel 1895
Class
Helicoplacoidea
Durham & Caster, 1963
Class
Edrioasteroidea
Billings, 1858
Class
Edrioblastoidea†
Fay, 1962
Class
Cyclocystoidea†
Miller & Gurley, 1895
Class
Ophiocistioidea
Solas, 1899
Class
Echinoidea
Leske, 1778
Class
Holothuroidea
de Blainville, 1834
Other proposed classes not included at that rank in any of the above taxonomies include:
Cryptosyringida
Smith, 1984
132
Somasteroidea
Spencer, 1951
133
Stenuroidea
Spencer, 1951
134
Coronoidea
Brett et al., 1983
135
Concentricycloidea
Baker, Rowe & Clark, 1986
136
There are also several common alternative names involving homalozoans:
Carpoidea
Jaekel, 1900
for Homalozoa, giving rise to the term "carpoids"
137
Cincta
Jaekel, 1918
as either the senior synonym of or sole order within Homostelea
138
Soluta
Jaekel, 1901
as either the senior synonym of or sole order within Homoiostelea
138
Calcichordata
Jeffries, 1967
, a subphylum effectively identical to Stylophora that was central
139
to the now-disproven
140
calcichordate hypothesis
Cladograms
edit
According to 2024 review, there are two main schools of thought regarding echinoderm phylogeny: One that sees pentaradiality as a
plesiomorphic
trait of the phylum, and another that considers it a derived trait (
apomorphy
).
141
Note that neither cladogram shown below includes all of the traditional classes, or even all of the classes mentioned in accompanying text.
Pentaradiality as a plesiomorphy
Supporters of pentaradiality as an initial condition of the phylum note that radial forms are the first uncontested echinoderms to appear in the fossil record. They also define homologies of echinoderm anatomy based on a division of the skeleton into two parts: those that are or are not associated with the water vascular system.
108
The following cladogram is based on David & Mooi (1999)
142
and David, Lefebvre, Mooi, and Parsley (2000),
143
although note that discussion of the cladogram in the latter paper notes that cinctans and ctenocystoids could instead emerge from within diploporites rather than eocrinoids:
Echinodermata
Arkarua
Helicoplacoidea
Edrioasteroidea
Blastozoa
Lepidocystoidea
Eocrinoidea
"†
some Eocrinoids†
some Eocrinoids†
some Eocrinoids†
Homostelea
(Cincta)
Ctenocystoidea
Homoiostelea
(Soluta)
Diploporita
Cystoidea
"†
Rhombifera
Blastoidea
Echinodermata
Crinozoa
Crinoidea
Stylophora
Eleutherozoa
Asterozoa
Ophiuroidea
Asteroidea
Echinozoa
Echinoidea
Ophiocistioidea
Holothuroidea
crown group
total group
In this theory, the controversial
144
Ediacaran
fossil
Arkarua
is tentatively placed as the sister to all other echinoderms.
Helicoplacoidea
Edrioasteroidea
, and the entirety of
Blastozoa
join it in the stem group.
Pelmatozoa
Eocrinoidea
, and
Cystoidea
are shown to be paraphyletic while
Homalozoa
is polyphyletic. The
Stylophora
are included within
Crinozoa
, with the discussion text noting that they are expected to be "well within the crinozoan clade, above [later than] the first forms to which the term ‘‘crinoid’’ is usually applied."
145
Pentaradiality as an apomorphy
Those who find pentaradiality to be derived incorporate the recently discovered fossils
Ctenoimbricata
(seen as a possible sister to all other echinoderms) and
Helicocystis
(seen as bridging the triradial helicoplacoids and the pentaradial crown group). They cite research indicating that the early appearance of pentaradial forms is likely due to an incomplete fossil record, as well as multiple studies showing non-radial forms as an early stem group, to argue that this is phylogeny represents an emerging consensus.
108
They reject
Arkarua
as an echinoderm due to its lack of
stereom
and possession of true pentaradiality instead of the 2-1-2 pseudo-pentaradiality seen in all early forms.
144
The following cladogram is based on Rahman & Zamora (2024),
146
incorporating class
147
and subphylum
148
names from the text:
Echinodermata
Ctenoimbricata
Ctenocystis
(a
Ctenocystoid
†)
Courtessolea
(a
Ctenocystoid
†)
"Homalozoa"†
Protocinctus
(a
Cinctan
† a.k.a. Homostelean†)
Coleicarpus
(a
Solute
† a.k.a. Homoiostelean†)
Ceratocystis
(a
Stylophoran
†)
Helicoplacus
(a
Helicoplacoid
†)
Helicocystis
Echinodermata
Gogia
(an
Eocrinoid
†)
Camptostroma
(an
Edrioasteroid
†)
Crinoidea
Eleutherozoa
Echinozoa
Echinoidea
Holothuroidea
Asterozoa
Asteroidea
Ophiuroidea
crown group
total group
Here,
Homalozoa
(with uncertain placement of
Stylophora
) is shown to be a paraphyletic assemblage along the stem group, followed by
Helicoplacoidea
and then
Helicocystis
as the sister of the crown group. The details of
Blastozoa
vs
Crinozoa
are not addressed, as they are represented only by the classes
Eocrinoidea
and
Crinoidea
, respectively, and the overall nature of
Pelmatozoa
remains unresolved. The four-way
polytomy
including the
Eleutherozoa
and
Crinoidea
shows either
Camptostroma
or
Gogia
or both could prove to be outside of the crown group.
Fossil history
edit
Echinoderms have a rich fossil record due to their mineralized endoskeletons.
149
150
Possible early echinoderms
edit
The three oldest known candidate echinoderms all lack
stereom
and other echinoderm
apomorphies
, making their inclusion in the phylum controversial.
151
Arkarua adami illustration by Pennetta
The oldest potential echinoderm
fossil
is
Arkarua
from the late
Ediacaran
of Australia
circa
555
Ma
. These fossils are disc-like, with radial ridges on the rim and a five-pointed central depression marked with radial lines. However, the fossils have no
stereom
or internal structure indicating a water vascular system, so they cannot be conclusively identified.
152
Additionally, all known early pentaradial echinoderms are pseudo-pentaradial in a 2-1-2 pattern, with true pentaradiality as seen in
Arkarua
not seen until the emergence of the
Eleutherozoa
151
The next possible echinoderms are the
vetulocystids
, which date to the early to mid
Cambrian
, 541–501 Ma. While the youngest vetulocystid,
Thylacocercus
, displays some characteristics that could be intermediate between older vetulocystids and
Yanjiahella
, its discoverers consider vetulocystids more likely to be stem ambulacrarians than stem echinoderms.
115
Artist's conception of
Y. biscarpa
Yanjiahella
, from the
Fortunian
circa
539–529 Ma), is unlike the older fossils in that it has a plated theca, albeit one without evidence of stereom. To some, this is a reason to place it as a stem ambulacrarian or stem hemichordate.
153
Others argue that absence of evidence for stereom is not evidence of absence, and consider a stem echinoderm position more likely.
154
Echinoderms in the Cambrian and Ordovician
edit
The first universally accepted echinoderms appear in the
Lower Cambrian
period; asterozoans appeared in the
Ordovician
, while the crinoids were a dominant group in the
Paleozoic
It is hypothesised that the ancestor of all echinoderms was a simple, motile, bilaterally symmetrical animal with a mouth, gut and anus. This ancestral organism adopted an attached mode of life with suspension feeding, and developed radial symmetry. Even so, the larvae of all echinoderms are bilaterally symmetrical, and all develop radial symmetry at metamorphosis. Like their ancestor, the starfish and crinoids still attach themselves to the seabed while changing to their adult form.
155
The first known echinoderms were non-motile,
156
157
but evolved into animals able to move freely. These soon developed endoskeletal plates with stereom structure, and external ciliary grooves for feeding.
158
The Paleozoic echinoderms were globular, attached to the
substrate
and were orientated with their oral surfaces facing upwards. These early echinoderms had
ambulacral grooves
extending down the side of the body, fringed on either side by
brachioles
, like the pinnules of a modern crinoid. Eventually, the mobile
eleutherozoans
reversed their orientation to become mouth-downward. Before this happened, the podia probably had a feeding function, as they do in the crinoids today. The locomotor function of the podia came later, when the re-orientation of the mouth brought the podia into contact with the substrate for the first time.
159
Early echinoderms
Ctenoimbricata
Ctenocystis
Gogia
Protocinctus
and
Rhenocystis
The Ordovician cystoid
Echinosphaerites
from northeastern Estonia
Fossil
crinoid
crowns
Calyx of
Hyperoblastus
, a
blastoid
from the
Devonian
of
Wisconsin
Use by humans
edit
As food and medicine
edit
Sea urchin being cut open to eat its eggs
Sea cucumbers as
traditional Chinese medicine
In 2019, 129,052 tonnes of echinoderms were harvested. The majority of these were sea cucumbers (59,262 tonnes) and sea urchins (66,341 tonnes).
160
These are used mainly for food, but also in
traditional Chinese medicine
161
Sea cucumbers are considered a delicacy in some countries of southeast Asia; as such, they are in imminent danger of being over-harvested.
162
Popular species include the pineapple roller
Thelenota ananas
susuhan
) and the red sea cucumber
Holothuria edulis
. These and other species are colloquially known as
bêche de mer
or
trepang
in
China
and
Indonesia
. The sea cucumbers are boiled for twenty minutes and then dried both naturally and later over a fire which gives them a smoky tang. In China, they are used as a basis for gelatinous soups and stews.
163
Both male and female gonads of sea urchins are consumed, particularly in
Japan
and
France
. The taste is described as soft and melting, like a mixture of seafood and fruit.
164
165
Sea urchin breeding trials have been undertaken to try to compensate for
overexploitation
166
In research
edit
Because of their robust larval growth, sea urchins are widely used in research, particularly as
model organisms
in
developmental biology
and ecotoxicology.
167
168
169
170
Strongylocentrotus purpuratus
and
Arbacia punctulata
are used for this purpose in embryological studies.
171
The large size and the transparency of the eggs enables the observation of
sperm
cells in the process of fertilising
ova
167
The arm regeneration potential of brittle stars is being studied in connection with understanding and treating
neurodegenerative
diseases in humans.
172
Genomic
data relevant to echinoderm model organisms are collected in
Echinobase
173
174
Currently, there are four species of echinoderms fully supported (gene pages, BLAST, JBrowse tracks, genome downloads) including
Strongylocentrotus purpuratus
(purple sea urchin),
Lytechinus variegatus
(green sea urchin),
Patiria miniata
(bat star) and
Acanthaster planci
(crown-of-thorns sea star). Partially supported species (no gene pages) include
Lytechinus pictus
(painted sea urchin),
Asterias rubens
(sugar star) and
Anneissia japonica
(feather star crinoid).
173
174
Other uses
edit
The calcareous tests or shells of echinoderms are used as a source of
lime
by farmers in areas where
limestone
is unavailable and some are used in the manufacture of
fish meal
175
4,000 tons of the animals are used annually for these purposes. This trade is often carried out in conjunction with
shellfish
farmers, for whom the starfish pose a major threat by eating their cultured stock. Other uses for the starfish they recover include the manufacture of animal feed, composting and the preparation of dried specimens for the arts and craft trade.
172
See also
edit
List of prehistoric echinoderm genera
References
edit
Smith, Zamora & Álvaro 2013
, p. 2
"echinoderm"
Dictionary.com Unabridged
(Online). n.d.
Hall 2022
"echinoderm"
Online Etymology Dictionary
Stokes 2021
ITIS
, Echinodermata
Ubaghs 1967
, p. S5, footnote 1
Bather 1900
Wray 1999
U. of Michigan Museum of Zoology
Uthicke, Schaffelke & Byrne 2009
Arnone, Byrne & Martinez 2015
Ruppert, Fox & Barnes 2004
, p. 873
Byrne, O'Hara & CSIRO 2017
, pp. 322–324
Holló & Novák 2012
Messing 2004
Formery et al. 2023
Lacali 2023
Behrens & Bäuerlein 2007
, p. 393
Brusca, Moore & Shuster 2016
, pp. 979–980
Davies 1925
, pp. 240–241
Perillo et al. 2020
Weber & Dambach 1974
Motokawa 1984
Brusca, Moore & Shuster 2016
, p. 980
Dorit, Walker & Barnes 1991
, pp. 780–791
Brusca, Moore & Shuster 2016
, pp. 980–982
Dorit, Walker & Barnes 1991
, pp. 784–785
Brusca, Moore & Shuster 2016
, p. 982
Dorit, Walker & Barnes 1991
, pp. 790–793
Jangoux 1982
, p. 244
Rigby, Iken & Shirayama 2007
, p. 44
Ruppert, Fox & Barnes 2004
, p. 885
Ruppert, Fox & Barnes 2004
, p. 891
Ruppert, Fox & Barnes 2004
, pp. 902–904
Ruppert, Fox & Barnes 2004
, p. 912
Ruppert, Fox & Barnes 2004
, p. 920
Moore & Overhill 2006
, p. 245
Hickman, Roberts & Larson 2003
, p. 271
Macrobenthos of the North Sea
, Echinodermata
Nielsen 2012
, p. 78
Dorit, Walker & Barnes 1991
, pp. 780–791
Ramirez-Gomez 2010
Smith 2010
Smith et al. 2010
Ruppert, Fox & Barnes 2004
, pp. 872–929
James, Siikavuopio & Johansson 2018
: "The GI [% of body weight made up by the gonad] of urchins in the wild can vary hugely and can be less than 1% or as high as 20%, whilst for cultured sea urchins GI values can be as high as 35%"
Ruppert, Fox & Barnes 2004
, pp. 872–929
Edmondson 1935
McAlary 1993
Hotchkiss 2000
, last paragraph in review above Analysis
Fisher 1925
Dobson et al. 1991
Candia-Carnevali, Thorndyke & Matranga 2009
Mashanov, Dolmatov & Heinzeller 2005
Young & Eckelbarger 1994
, pp. 179–194
Ruppert, Fox & Barnes 2004
, pp. 887–888
Ruppert, Fox & Barnes 2004
, p. 895
Ruppert, Fox & Barnes 2004
, p. 888
Ruppert, Fox & Barnes 2004
, p. 908
Ruppert, Fox & Barnes 2004
, p. 916
Ruppert, Fox & Barnes 2004
, p. 922
Yamaguchi & Lucas 1984
McGovern 2002
Monks 1904
Kille 1942
Eaves & Palmer 2003
Jaeckle 1994
Vaughn 2009
McDonald & Vaughn 2010
Vaughn & Strathmann 2008
Vaughn 2010
Dorit, Walker & Barnes 1991
, p. 778
Brusca, Moore & Shuster 2016
, pp. 997–998
Dorit, Walker & Barnes 1991
, p. 778
van Egmond 2000
Brusca, Moore & Shuster 2016
, p. 968
Wang, Hagdorn & Wang 2006
Smith 1937
Astley 2012
Brusca, Moore & Shuster 2016
, pp. 982–983
Sea Stars of the Pacific Northwest
, Sand Star –
Luidia foliolata
Ruppert, Fox & Barnes 2004
, pp. 899–900
Ruppert, Fox & Barnes 2004
, pp. 911–912
Messing 2006
Barnes 1982
, pp. 997–1007
Ruppert, Fox & Barnes 2004
, p. 893
Carefoot 2011b
Ruppert, Fox & Barnes 2004
, p. 914
Ruppert, Fox & Barnes 2004
, pp. 884–885
Carefoot 2011a
Ruppert, Fox & Barnes 2004
, p. 893
Carefoot 2011c
Ruppert, Fox & Barnes 2004
, p. 914
Ruppert, Fox & Barnes 2004
, pp. 884–885
Miller 1998
Dorit, Walker & Barnes 1991
, p. 779
Dorit, Walker & Barnes 1991
, pp. 789–790
Mladenov et al. 1989
Brusca, Moore & Shuster 2016
, p. 968
Herrera-Escalante, López-Pérez & Leyte-Morales 2005
Lebrato et al. 2010
Osborne 2000
, p. 464
Lawrence 1975
Birkeland & Lucas 1990
Ubaghs 1978
Smith 1984
Rahman & Zamora 2024
, pp. 308–309
Nanglu et al. 2023
Dorit, Walker & Barnes 1991
, pp. 777–779
Fox 2007
Edgecombe et al. 2011
Shu et al. 2004
, pp. 426–427
Topper et al. 2019
, pp. 5–7
Conway Morris et al. 2015
, pp. 4–6
Zamora et al. 2020
, p. 2
Mussini et al. 2024
, supplemental data figure S4
Li et al. 2023
, p. 159
Telford et al. 2014
Escriva et al. 2015
Smith 1984
, pp. 433–434
Moore 1966
, pp. U2–U3
Sprinkle 1973
, p. 3
Sprinkle 1973
Smith 1984
, p. 436
Bather 1900
Moore 1966
Ubaghs 1967
Sprinkle 1980a
Sprinkle 1980b
Ubaghs 1967
, p. S5, footnote 1
Smith 1984
, pp. 436–439, 453–454
PBDB Somasteroidea
PBDB Stenuroidea
PBDB Coronoidea
Rowe, Baker & Clark 1988
Rahman 2009
Rozhnov 2022
, p. 1310
Gee 1996
, p. 223
Lefebvre et al. 2019
Rahman & Zamora 2024
, p. 308
David & Mooi 1999
, p. 100
David et al. 2000
, p. 549
Rahman & Zamora 2024
, p. 300
David et al. 2000
, p. 550
Rahman & Zamora 2024
, p. 310
Rahman & Zamora 2024
, p. 311
Rahman & Zamora 2024
, p. 298
Rahman & Zamora 2024
, p. 296
Waggoner 1995
Rahman & Zamora 2024
, pp. 299–303
Smith 2005
Zamora et al. 2020
Topper et al. 2020
Dorit, Walker & Barnes 1991
, pp. 792–793
Dorit, Walker & Barnes 1991
, pp. 792–793
Dornbos & Bottjer 2000
UCMP Berkeley
, Echinodermata: Morphology
Dorit, Walker & Barnes 1991
, pp. 792–793
FAO
, B-76
Pangestuti & Arifin 2018
NYTimes 2009
Wikisource:1911 Encyclopædia Britannica/Bêche-de-Mer
Lawrence 2001
Davidson 2014
, p. 730
Sartori et al. 2015
Exploratorium
Sartori & Gaion 2015
Gaion et al. 2013
Hart 2002
Longo & Anderson 1969
Barkhouse, Niles & Davidson 2007
Arshinoff et al. 2022
Telmer et al. 2024
Wild Singapore
, Sea Stars
Works cited
edit
Arnone, Maria Ina; Byrne, Maria; Martinez, Pedro (2015). "Echinodermata".
Evolutionary Developmental Biology of Invertebrates 6
. Vienna: Springer Vienna. pp.
1–
58.
doi
10.1007/978-3-7091-1856-6_1
ISBN
978-3-7091-1855-9
Arshinoff, Bradley I; Cary, Gregory A.; Karimi, Kamran; Foley, Saoirse; Agalakov, Sergei; Delgado, Francisco; Lotay, Vaneet S.; Ku, Carolyn J.; Pells, Troy J.; Beatman, Thomas R.; Kim, Eugene; Cameron, R. Andrew; Vize, Peter D.; Telmer, Cheryl A.; Croce, Jenifer C.; Ettensohn, Charles A; Hinman, Veronica F. (7 January 2022).
"Echinobase: leveraging an extant model organism database to build a knowledgebase supporting research on the genomics and biology of echinoderms"
Nucleic Acids Research
50
(D1):
D970–
D979.
doi
10.1093/nar/gkab1005
PMC
8728261
PMID
34791383
Astley, H. C. (2012).
"Getting around when you're round: Quantitative analysis of the locomotion of the blunt-spined brittle star, Ophiocoma echinata"
Journal of Experimental Biology
215
(11):
1923–
1929.
Bibcode
2012JExpB.215.1923A
doi
10.1242/jeb.068460
PMID
22573771
Barkhouse, C.; Niles, M.; Davidson, L. A. (2007).
"A literature review of sea star control methods for bottom and off bottom shellfish cultures"
(PDF)
Canadian Industry Report of Fisheries and Aquatic Sciences
279
(7):
14–
15. Archived from
the original
(PDF)
on 22 May 2013.
Barnes, Robert D. (1982).
Invertebrate Zoology
. Holt-Saunders International.
ISBN
0-03-056747-5
Bather, F. A. (1900). "Chapter VIII: General Description of the Echinoderma". In Lankester, E. Ray (ed.).
A Treatise on Zoology, Part III: The Echinoderma
. Vol. 6. London: Adam & Charles Black. pp.
1–
37.
doi
10.1080/00222930008678384
Behrens, Peter; Bäuerlein, Edmund (2007).
Handbook of Biomineralization: Biomimetic and bioinspired chemistry'
. Wiley-VCH.
ISBN
978-3-527-31805-6
Birkeland, Charles; Lucas, John S. (1990). "Effects of
A. planci
on Coral-Reef Communities".
Acanthaster planci
: Major Management Problem of Coral Reefs
. Florida: CRC Press. pp.
148–
159.
ISBN
0-8493-6599-6
Brusca, Richard C.; Moore, Wendy; Shuster, Stephen M. (2016).
Invertebrates
(3rd ed.). Sunderland, Massachusetts.
ISBN
978-1-60535-375-3
OCLC
928750550
{{
cite book
}}
: CS1 maint: location missing publisher (
link
Byrne, Marie; O'Hara, Tim; CSIRO (2017).
Australian echinoderms: biology, ecology and evolution
. Clayton South, Victoria.
ISBN
978-1-4863-0763-0
OCLC
960042778
{{
cite book
}}
: CS1 maint: location missing publisher (
link
Candia-Carnevali, M. D.; Thorndyke, M. C.; Matranga, V. (2009).
"Regenerating Echinoderms: A Promise to Understand Stem Cells Potential"
. In Rinkevich, B.; Matranga, V. (eds.).
Stem Cells in Marine Organisms
. Dordrecht:
Springer
. pp.
165–
186.
doi
10.1007/978-90-481-2767-2_7
ISBN
978-90-481-2766-5
Carefoot, Tom (2011a).
"Learn about feather stars: feeding & growth"
A Snail's Odyssey
. Archived from
the original
on 12 January 2013
. Retrieved
23 February
2013
Carefoot, Tom (2011b).
"Learn about sea urchins: feeding, nutrition & growth"
A Snail's Odyssey
. Archived from
the original
on 22 March 2013
. Retrieved
23 February
2013
Carefoot, Tom (2011c).
"Learn about sand dollars: feeding & growth"
A Snail's Odyssey
. Archived from
the original
on 19 October 2012
. Retrieved
23 February
2013
Conway Morris, Simon; Halgedahl, Susan L.; Selden, Paul; Jarrard, Richard D. (2015).
"Rare primitive deuterostomes from the Cambrian (Series 3) of Utah"
(PDF)
Journal of Paleontology
89
(4):
631–
636.
Bibcode
2015JPal...89..631C
doi
10.1017/jpa.2015.40
David, Bruno; Lefebvre, Bertrand; Mooi, Rich; Parsley, Ronald (December 2000). "Are homalozoans echinoderms? An answer from the extraxial-axial theory".
Paleobiology
26
(4):
520–
555.
Bibcode
2000Pbio...26..529D
doi
10.1666/0094-8373(2000)026<0529:AHEAAF>2.0.CO;2
David, Bruno; Mooi, Rich (January 1999).
"Contributions of the extraxial-axial theory to understanding the echinoderms"
Bulletin de la Société Géologique de France
170
(1):
91–
101
. Retrieved
28 October
2024
Davidson, Alan (2014).
Oxford Companion to Food
(3rd ed.).
Oxford University Press
Davies, A. Morley (1925).
An Introduction to Palaeontology
. Thomas Murby.
Dorit, R. L.; Walker, W. F.; Barnes, R. D. (1991).
Zoology, International edition
. Saunders College Publishing.
ISBN
978-0-03-030504-7
Dobson, W. E.; Stancyk, S. E.; Clements, L. A.; Showman, R. M. (1 February 1991).
"Nutrient Translocation during Early Disc Regeneration in the Brittlestar
Microphiopholis gracillima
(Stimpson) (Echinodermata: Ophiuroidea)"
Biol Bull
180
(1):
167–
184.
doi
10.2307/1542439
JSTOR
1542439
PMID
29303627
. Retrieved
14 July
2011
Dornbos, Stephen Q.; Bottjer, David J. (2000). "Evolutionary paleoecology of the earliest echinoderms: Helicoplacoids and the Cambrian substrate revolution".
Geology
28
(9). Geological Society of America: 839.
Bibcode
2000Geo....28..839D
doi
10.1130/0091-7613(2000)28<839:epotee>2.0.co;2
Eaves, Alexandra A.; Palmer, A. Richard (11 September 2003). "Reproduction: Widespread cloning in echinoderm larvae".
Nature
425
(6954): 146.
Bibcode
2003Natur.425..146E
doi
10.1038/425146a
hdl
10402/era.17195
PMID
12968170
S2CID
4430104
Edgecombe, Gregory D.; Giribet, Gonzalo; Dunn, Casey W.; Hejnol, Andreas; Kristensen, Reinhardt M.; Neves, Ricardo C.; Rouse, Greg W.; Worsaae, Katrine; Sørensen, Martin V. (June 2011).
"Higher-level metazoan relationships: recent progress and remaining questions"
Organisms, Diversity & Evolution
11
(2):
151–
172.
Bibcode
2011ODivE..11..151E
doi
10.1007/s13127-011-0044-4
S2CID
32169826
Edmondson, C.H. (1935).
"Autotomy and regeneration of Hawaiian starfishes"
(PDF)
Bishop Museum Occasional Papers
11
(8):
3–
20.
Archived
(PDF)
from the original on 9 October 2022.
Escriva, Hector; Reich, Adrian; Dunn, Casey; Akasaka, Koji; Wessel, Gary (2015).
"Phylogenomic Analyses of Echinodermata Support the Sister Groups of Asterozoa and Echinozoa"
PLOS ONE
10
(3) e0119627.
Bibcode
2015PLoSO..1019627R
doi
10.1371/journal.pone.0119627
PMC
4368666
PMID
25794146
Fisher, W. K. (1 March 1925).
"Asexual Reproduction in the Starfish,
Sclerasterias
(PDF)
Biological Bulletin
48
(3):
171–
175.
doi
10.2307/1536659
JSTOR
1536659
Archived
(PDF)
from the original on 9 October 2022
. Retrieved
15 July
2011
Formery, L.; Peluso, P.; Kohnle, I.; Malnick, J.; Thompson, J. R.; Pitel, M.; Uhlinger, K. R.; Rokhsar, D. S.; Rank, D. R.; Lowe, C. J. (2023).
"Molecular evidence of anteroposterior patterning in adult echinoderms"
Nature
623
(7987):
555–
561.
Bibcode
2023Natur.623..555F
doi
10.1038/s41586-023-06669-2
ISSN
1476-4687
PMID
37914929
Fox, Richard (25 May 2007).
Asterias forbesi
Invertebrate Anatomy OnLine
. Lander University
. Retrieved
19 May
2012
Gaion, A.; Scuderi, A.; Pellegrini, D.; Sartori, D. (2013). "Arsenic Exposure Affects Embryo Development of Sea Urchin, Paracentrotus lividus (Lamarck, 1816)".
Bulletin of Environmental Contamination and Toxicology
39
(2):
124–
8.
doi
10.3109/01480545.2015.1041602
PMID
25945412
S2CID
207437380
Gee, Henry (1996). "Calcichordates, ball by ball".
Before the Backbone: Views on the origins of vertebrates
. London: Chapman & Hall. pp.
221–
286.
Hall, Danielle (3 February 2022).
"Echinoderms | Smithsonian Ocean"
ocean.si.edu
. Retrieved
31 March
2023
Hart, M. W. (January–February 2002). "Life history evolution and comparative developmental biology of echinoderms".
Evolution and Development
(1):
62–
71.
doi
10.1046/j.1525-142x.2002.01052.x
PMID
11868659
S2CID
39175905
Herrera-Escalante, T.; López-Pérez, R. A.; Leyte-Morales, G. E. (2005). "Bioerosion caused by the sea urchin
Diadema mexicanum
(Echinodermata: Echinoidea) at Bahías de Huatulco, Western Mexico".
Revista de Biología Tropical
53
(3):
263–
273.
PMID
17469255
Hickman, C. Jr.; Roberts, L.; Larson, A. (2003).
Animal Diversity
. Granite Hill Publishers.
ISBN
978-0-07-119549-2
OCLC
1148032077
Holló, Gábor; Novák, Mihály (2012).
"The manoeuvrability hypothesis to explain the maintenance of bilateral symmetry in animal evolution"
Biology Direct
22.
doi
10.1186/1745-6150-7-22
PMC
3438024
PMID
22789130
Hotchkiss, Frederick H. C. (1 June 2000).
"On the Number of Rays in Starfish"
American Zoologist
40
(3):
340–
354.
doi
10.1093/icb/40.3.340
Jaeckle, William B. (1 February 1994).
"Multiple Modes of Asexual Reproduction by Tropical and Subtropical Sea Star Larvae: An Unusual Adaptation for Genet Dispersal and Survival"
(PDF)
Biological Bulletin
186
(1):
62–
71.
doi
10.2307/1542036
JSTOR
1542036
PMID
29283296
Archived
(PDF)
from the original on 9 October 2022
. Retrieved
13 July
2011
James, Philip; Siikavuopio, Sten; Johansson, Gunhild Seljehaug (2018).
"A Guide to the Sea Urchin Reproductive Cycle and Staging Sea Urchin Gonad Samples"
(PDF)
. Nofima.
Archived
(PDF)
from the original on 9 October 2022
. Retrieved
21 June
2022
Jangoux, Michel (1982).
"11. Digestive Systems"
. In Jangoux, Michel; Lawrence, John M. (eds.).
Echinoderm Nutrition
. Rotterdam: A. A. Balkema. pp.
235–
272.
ISBN
978-90-6191-080-0
Kille, Frank R. (1942).
"Regeneration of the Reproductive System Following Binary Fission in the Sea-Cucumber,
Holothuria parvula
(Selenka)"
(PDF)
Biological Bulletin
83
(1):
55–
66.
doi
10.2307/1538013
JSTOR
1538013
Archived
(PDF)
from the original on 9 October 2022.
Lacali, Thurston (2023).
"A radical evolutionary makeover gave echinoderms their unusual body plan"
Nature
623
(7987):
485–
486.
Bibcode
2023Natur.623..485L
doi
10.1038/d41586-023-03123-1
ISSN
1476-4687
PMID
37914869
Lawrence, J. M. (1975).
"On the relationships between marine plants and sea urchins"
(PDF)
Oceanographic Marine Biological Annual Review
13
213–
286. Archived from
the original
(PDF)
on 5 February 2011.
Lawrence, John M. (2001). "The edible sea urchins". In Lawrence, John M. (ed.).
Edible Sea Urchins: Biology and Ecology
. Developments in Aquaculture and Fisheries Science. Vol. 37. pp.
1–
4.
doi
10.1016/S0167-9309(01)80002-8
ISBN
978-0-444-50390-9
Lebrato, Mario; Iglesias-Rodríguez, Debora; Feely, Richard A.; Greeley, Dana; Jones, Daniel O. B.; Suarez-Bosche, Nadia; Lampitt, Richard S.; Cartes, Joan E.; Green, Darryl R. H.; Alker, Belinda (2010).
"Global contribution of echinoderms to the marine carbon cycle: CaCO3 budget and benthic compartments"
Ecological Monographs
80
(3):
441–
467.
Bibcode
2010EcoM...80..441L
doi
10.1890/09-0553.1
hdl
10261/79231
Lefebvre, Bertrand; Guensburg, Thomas E.; Martin, Emmanuel L.O.; Mooi, Rich; Nardin, Elise; Nohejlová, Martina; Saleh, Farid; Kouraïss, Khaoula; El Hariri, Khadija; David, Bruno (2019).
"Exceptionally preserved soft parts in fossils from the Lower Ordovician of Morocco clarify stylophoran affinities within basal deuterostomes"
Geobios
52
27–
36.
Bibcode
2019Geobi..52...27L
doi
10.1016/j.geobios.2018.11.001
ISSN
0016-6995
Li, Yujing; Dunn, Frances S.; Murdock, Duncan J.E.; Guo, Jin; Rahman, Imran A.; Cong, Peiyun (10 May 2023).
"Cambrian stem-group ambulacrarians and the nature of the ancestral deuterostome"
Current Biology
33
(12): 2359–2366.e2.
Bibcode
2023CBio...33E2359L
doi
10.1016/j.cub.2023.04.048
hdl
10141/623055
PMID
37167976
S2CID
258592223
Longo, F. J.; Anderson, E. (June 1969). "Sperm differentiation in the sea urchins
Arbacia punctulata
and
Strongylocentrotus purpuratus
".
Journal of Ultrastructure Research
27
(5):
486–
509.
doi
10.1016/S0022-5320(69)80046-8
PMID
5816822
Mashanov, Vladimir S.; Dolmatov, Igor Yu.; Heinzeller, Thomas (1 December 2005).
"Transdifferentiation in Holothurian Gut Regeneration"
The Biological Bulletin
209
(3):
184–
193.
doi
10.2307/3593108
JSTOR
3593108
PMID
16382166
S2CID
27847466
McAlary, Florence A. (1993).
Population Structure and Reproduction of the Fissiparous Seastar,
Linckia columbiae
Gray, on Santa Catalina Island, California
. 3rd California Islands Symposium. National Park Service
. Retrieved
15 April
2012
McDonald, Kathryn A.; Vaughn, Dawn (1 August 2010).
"Abrupt Change in Food Environment Induces Cloning in Plutei of
Dendraster excentricus
Biological Bulletin
219
(1):
38–
49.
doi
10.1086/BBLv219n1p38
PMID
20813988
S2CID
24422314
. Retrieved
16 July
2011
McGovern, Tamara M. (5 April 2002).
"Patterns of sexual and asexual reproduction in the brittle star
Ophiactis savignyi
in the Florida Keys"
(PDF)
Marine Ecology Progress Series
230
119–
126.
Bibcode
2002MEPS..230..119M
doi
10.3354/meps230119
Archived
(PDF)
from the original on 9 October 2022.
Messing, Charles (2004).
"Crown and calyx"
Charles Messing's Crinoid Pages
. Archived from
the original
on 29 October 2013
. Retrieved
29 July
2012
Messing, Charles (2006).
"The crinoid feeding mechanism"
Charles Messing's Crinoid Pages
. Archived from
the original
on 14 January 2013
. Retrieved
26 July
2012
Miller, John E. (20 July 1998).
"Echinoderm: role in nature"
Encyclopædia Britannica
. Retrieved
23 June
2022
Mladenov, Philip V.; Igdoura, Suleiman; Asotra, Satish; Burke, Robert D. (1 April 1989).
"Purification and partial characterisation of an autotomy-promoting factor from the sea star
Pycnopodia Helianthoides
The Biological Bulletin
176
(2):
169–
175.
doi
10.2307/1541585
JSTOR
1541585
Monks, Sarah P. (1 April 1904). "Variability and Autotomy of
Phataria
".
Proceedings of the Academy of Natural Sciences of Philadelphia
56
(2):
596–
600.
JSTOR
4063000
Moore, Janet; Overhill, Raith (2006).
An Introduction to the Invertebrates
(2nd ed.). Cambridge University Press.
ISBN
978-0-521-67406-5
Moore, Raymond C. (1966). "Introduction". In Moore, Raymond C. (ed.).
Treatise on Invertebrate Paleontology, Part U: Echinodermata 3
. Vol. 1. University of Kansas Press. pp.
U1–
U3
. Retrieved
28 October
2024
Motokawa, Tatsuo (May 1984). "Connective tissue catch in echinoderms".
Biological Reviews
59
(2):
255–
270.
doi
10.1111/j.1469-185X.1984.tb00409.x
S2CID
86391676
Mussini, G.; Smith, M. P.; Vinther, J.; Rahman, I. A.; Murdock, D. J. E.; Harper, D. A. T.; Dunn, F. S. (2024).
"A new interpretation of
Pikaia
reveals the origins of the chordate body plan"
Current Biology
34
(13): 2980–2989.e2.
Bibcode
2024CBio...34.2980M
doi
10.1016/j.cub.2024.05.026
hdl
10141/623098
PMID
38866005
Nanglu, Karma; Cole, Selina R.; Wright, David F.; Souto, Camilla (2023). "Worms and gills, plates and spines: the evolutionary origins and incredible disparity of deuterostomes revealed by fossils, genes, and development".
Biological Reviews
98
(1):
316–
351.
doi
10.1111/brv.12908
PMID
36257784
Nielsen, Claus (2012).
Animal Evolution: Interrelationships of the Living Phyla
(3rd ed.). Oxford University Press.
ISBN
978-0-19-960602-3
Osborne, Patrick L. (2000).
Tropical Ecosystem and Ecological Concepts
. Cambridge University Press.
ISBN
0-521-64523-9
Pangestuti, Ratih; Arifin, Zainal (2018).
"Medicinal and health benefit effects of functional sea cucumbers"
Journal of Traditional and Complementary Medicine
(3):
341–
351.
doi
10.1016/j.jtcme.2017.06.007
PMC
6035309
PMID
29992105
Perillo, Margherita; Oulhen, Nathalie; Foster, Stephany; Spurrell, Maxwell; Calestani, Cristina; Wessel, Gary (19 August 2020).
"Regulation of dynamic pigment cell states at single-cell resolution"
eLife
doi
10.7554/elife.60388
PMC
7455242
PMID
32812865
Rahman, Imran
(January–February 2009).
"Making sense of carpoids"
Geology Today
25
(1):
34–
38.
Bibcode
2009GeolT..25...34R
doi
10.1111/j.1365-2451.2009.00703.x
Rahman, Imran A.; Zamora, Samuel (July 2024).
"Origin and early evolution of echinoderms"
Annual Review of Earth and Planetary Sciences
52
(1):
295–
320.
Bibcode
2024AREPS..52..295R
doi
10.1146/annurev-earth-031621-113343
hdl
10141/623070
Ramirez-Gomez, Francisco (27 September 2010).
"Echinoderm Immunity"
Invertebrate Survival Journal
Rigby, P. Robin; Iken, Katrin; Shirayama, Yoshihisa (2007).
Sampling Biodiversity in Coastal Communities: NaGISA Protocols for Seagrass and Macroalgal Habitats
. NUS Press.
ISBN
978-9971-69-368-8
Rowe, F. W. E.; Baker, A. N.; Clark, H. E. S. (23 May 1988). "The Morphology, Development and Taxonomic Status of Xyloplax Baker, Rowe and Clark (1986) (Echinodermata: Concentricycloidea), with the Description of a New Species".
Proceedings of the Royal Society of London. Series B, Biological Sciences
233
(1237):
431–
459.
Bibcode
1988RSPSB.233..431R
doi
10.1098/rspb.1988.0032
Rozhnov, S. V. (2022). "Solutans (Echinoderms): Evolution Frozen between Torsion and Pentaradiality".
Paleontological Journal
56
(11):
1306–
1321.
Bibcode
2022PalJ...56.1306R
doi
10.1134/S0031030122110144
Ruppert, Edward E.; Fox, Richard, S.; Barnes, Robert D. (2004).
Invertebrate Zoology
(7th ed.). Cengage Learning.
ISBN
81-315-0104-3
{{
cite book
}}
: CS1 maint: multiple names: authors list (
link
Sartori, D.; Gaion, A. (2015). "Toxicity of polyunsaturated aldehydes of diatoms to Indo-Pacific bioindicator organism Echinometra mathaei".
Drug and Chemical Toxicology
39
(2):
124–
8.
doi
10.3109/01480545.2015.1041602
PMID
25945412
S2CID
207437380
Sartori, D.; Scuderi, A.; Sansone, G.; Gaion, A. (February 2015). "Echinoculture: the rearing of Paracentrotus lividus in a recirculating aquaculture system—experiments of artificial diets for the maintenance of sexual maturation".
Aquaculture International
23
(1):
111–
125.
Bibcode
2015AqInt..23..111S
doi
10.1007/s10499-014-9802-6
S2CID
18856183
Shu, D.-G.; Conway Morris, S.; Han, J.; Zhang, Z.-F.; Liu, J.-N. (2004).
"Ancestral echinoderms from the Chengjiang deposits of China"
Nature
430
(6998):
422–
428.
Bibcode
2004Natur.430..422S
doi
10.1038/nature02648
PMID
15269760
S2CID
4421182
Smith, Andrew B. (1984).
"Classification of the Echinodermata"
(PDF)
Palaeontology
27
(3):
431–
459
. Retrieved
28 October
2024
Smith, A.; Zamora, S.; Álvaro, J. (22 January 2013). "The oldest echinoderm faunas from Gondwana show that echinoderm body plan diversification was rapid".
Nature Communications
1385.
Bibcode
2013NatCo...4.1385S
doi
10.1038/ncomms2391
PMID
23340425
Smith, Dave (28 September 2005).
"Vendian Animals:
Arkarua
. Retrieved
14 March
2013
Smith, J. E. (1937).
"The structure and function of the tube feet in certain echinoderms"
(PDF)
Journal of the Marine Biological Association of the United Kingdom
22
(1):
345–
357.
Bibcode
1937JMBUK..22..345S
doi
10.1017/S0025315400012042
S2CID
55933156
. Archived from
the original
(PDF)
on 15 November 2013.
Smith, L. Courtney (January 2010).
"Echinoderm Immunity"
Invertebrate Immunity
. Advances in Experimental Medicine and Biology. Vol. 708. pp.
260–
301.
doi
10.1007/978-1-4419-8059-5_14
ISBN
978-1-4419-8058-8
PMID
21528703
Smith, L. Courtney; Ghosh, Julie; Buckley, Katherine M.; et al. (2010). "Echinoderm Immunity".
Invertebrate Immunity
. Advances in Experimental Medicine and Biology. Vol. 708. Boston, Massachusetts: Springer. pp.
260–
301.
doi
10.1007/978-1-4419-8059-5_14
ISBN
978-1-4419-8058-8
PMID
21528703
Sprinkle, James (1973).
"Morphology and evolution of blastozoan echinoderms"
Special Publication of the Museum of Comparative Zoology, Harvard University
. Retrieved
29 October
2024
Sprinkle, James (1980a). "Origin of blastoids: new look at an old problem (Abst.)".
Geological Society of America Abstracts with Programs
12
(7): 528.
Sprinkle, J. (1980b). "An Overview of the Fossil Record".
Notes for a Short Course: Studies in Geology
15–
26.
doi
10.1017/S0271164800000063
Stokes, Robert B. (2021). "Attribution of the taxon name Echinodermata to Klein, 1778".
Zootaxa
5061
(1):
199–
200.
doi
10.11646/zootaxa.5061.1.13
PMID
34810630
Telford, M. J.; Lowe, C. J.; Cameron, C. B.; Ortega-Martinez, O.; Aronowicz, J.; Oliveri, P.; Copley, R. R. (2014).
"Phylogenomic analysis of echinoderm class relationships supports Asterozoa"
Proceedings of the Royal Society B: Biological Sciences
281
(1786) 20140479.
doi
10.1098/rspb.2014.0479
PMC
4046411
PMID
24850925
Telmer, Cheryl; Karimi, Kamran; Chess, Macie; Agalakov, Sergei; Arshinoff, Bradley; Lotay, Vaneet; Wang, Dong Zhuo; Chu, Stanley; Pells, Troy; Vize, Peter; Hinman, Veronica; Ettensohn, Charles (2024).
"Echinobase: a resource to support the echinoderm research community"
Genetics
227
doi
10.1093/genetics/iyae002
PMC
11075573
PMID
38262680
Topper, Timothy P.; Guo, Junfeng; Clausen, Sébastien; Skovsted, Christian B.; Zhang, Zhifei (25 March 2019).
"A stem group echinoderm from the basal Cambrian of China and the origins of Ambulacraria"
Nature Communications
10
(1) 1366.
Bibcode
2019NatCo..10.1366T
doi
10.1038/s41467-019-09059-3
ISSN
2041-1723
PMC
6433856
PMID
30911013
Topper, Timothy P.; Guo, Junfeng; Clausen, Sébastien; Skovsted, Christian B.; Zhang, Zhifei (9 September 2020).
"Reply to 'Re-evaluating the phylogenetic position of the enigmatic early Cambrian deuterostome Yanjiahella'
Nature Communications
11
(1) 1287.
Bibcode
2020NatCo..11.1287T
doi
10.1038/s41467-020-14922-9
ISSN
2041-1723
PMC
7062690
PMID
32152290
Ubaghs, Georges (1967). "General Characters of Echinodermata". In Moore, Raymond C. (ed.).
Treatise on Invertebrate Paleontology, Part S: Echinodermata 1
. Vol. 1. University of Kansas Press. pp.
S3–
S60
. Retrieved
29 October
2024
Ubaghs, Georges (1978). "Classification of the Echinoderms". In Moore, Raymond C. (ed.).
Treatise on Invertebrate Paleontology, Part T: Echinodermata 2
. Vol. 1. University of Kansas Press. pp.
T359–
T367
. Retrieved
29 October
2024
Uthicke, Sven; Schaffelke, Britta; Byrne, Maria (1 January 2009).
"A boom–bust phylum? Ecological and evolutionary consequences of density variations in echinoderms"
Ecological Monographs
79
(1):
3–
24.
Bibcode
2009EcoM...79....3U
doi
10.1890/07-2136.1
van Egmond, Wim (1 July 2000).
"Gallery of Echinoderm Larvae"
. Microscopy UK
. Retrieved
2 February
2013
Waggoner, Ben (16 January 1995).
"Echinodermata: Fossil Record"
Introduction to the Echinodermata
. Museum of Paleontology: University of California at Berkeley
. Retrieved
14 March
2013
Weber, W.; Dambach, M. (April 1974). "Light-sensitivity of isolated pigment cells of the sea urchin
Centrostephanus longispinus
".
Cell and Tissue Research
148
(3):
437–
440.
doi
10.1007/BF00224270
PMID
4831958
S2CID
1669387
Vaughn, Dawn (October 2009).
"Predator-Induced Larval Cloning in the Sand Dollar
Dendraster excentricus
: Might Mothers Matter?"
Biological Bulletin
217
(2):
103–
114.
doi
10.1086/BBLv217n2p103
PMID
19875816
S2CID
26030855
Vaughn, Dawn (March 2010). "Why run and hide when you can divide? Evidence for larval cloning and reduced larval size as an adaptive inducible defense".
Marine Biology
157
(6):
1301–
1312.
Bibcode
2010MarBi.157.1301V
doi
10.1007/s00227-010-1410-z
S2CID
84336247
Vaughn, Dawn; Strathmann, Richard R. (14 March 2008).
"Predators induce cloning in echinoderm larvae"
Science
319
(5869): 1503.
Bibcode
2008Sci...319.1503V
doi
10.1126/science.1151995
JSTOR
40284699
PMID
18339931
S2CID
206509992
. Retrieved
16 July
2011
Wang, Xiaofeng; Hagdorn, Hans; Wang, Chuanshang (September 2006). "Pseudoplanktonic lifestyle of the Triassic crinoid
Traumatocrinus
from Southwest China".
Lethaia
39
(3):
187–
193.
Bibcode
2006Letha..39..187X
doi
10.1080/00241160600715321
Wray, Gregory A. (1999).
"Echinodermata: Spiny-skinned animals: sea urchins, starfish, and their allies"
Tree of Life
. Archived from
the original
on 23 May 2015
. Retrieved
19 October
2012
Yamaguchi, M.; Lucas, J. S. (1984). "Natural parthenogenesis, larval and juvenile development, and geographical distribution of the coral reef asteroid
Ophidiaster granifer
".
Marine Biology
83
(1):
33–
42.
Bibcode
1984MarBi..83...33Y
doi
10.1007/BF00393083
S2CID
84475593
Young, Craig M.; Eckelbarger, Kevin J. (1994).
Reproduction, Larval Biology, and Recruitment of the Deep-Sea Benthos
. Columbia University Press.
ISBN
0-231-08004-2
Zamora, Samuel; Wright, David F.; Mooi, Rich; Lefebvre, Bertrand; Guensburg, Thomas E.; Gorzelak, Przemysław; David, Bruno; Sumrall, Colin D.; Cole, Selina R.; Hunter, Aaron W.; Sprinkle, James (3 September 2020).
"Re-evaluating the phylogenetic position of the enigmatic early Cambrian deuterostome Yanjiahella"
Nature Communications
11
(1) 1286.
Bibcode
2020NatCo..11.1286Z
doi
10.1038/s41467-020-14920-x
ISSN
2041-1723
PMC
7063041
PMID
32152310
"Insight from the Sea Urchin"
Microscope Imaging Station
. Exploratorium.
Archived
from the original on 5 February 2018
. Retrieved
23 June
2022
"B-76 Sea-urchins and other echinoderms Capture production by species, fishing areas and countries or areas"
(PDF)
. FAO. pp.
463–
465.
Archived
(PDF)
from the original on 9 October 2022
. Retrieved
23 June
2022
"ITIS - Report: Echinodermata"
Integrated Taxonomic Information System
. Retrieved
2 November
2024
"Macrobenthos of the North Sea - Echinodermata > Introduction"
etibioinformatics.nl
"Sea Cucumbers Threatened by Asian Trade"
The New York Times
. April 2009
. Retrieved
1 April
2009
"Coronoidea"
The Paleobiology Database
. Retrieved
4 November
2024
"Somasteroidea"
The Paleobiology Database
. Retrieved
4 November
2024
"Stenuroidea"
The Paleobiology Database
. Retrieved
10 November
2024
"Sand star -
Luidia foliolata
. Sea Stars of the Pacific Northwest. Archived from
the original
on 9 September 2012
. Retrieved
26 September
2012
UCMP Berkeley.
"Echinodermata: Morphology"
University of California Museum of Paleontology
. Retrieved
21 March
2011
"Animal Diversity Web - Echinodermata"
. University of Michigan Museum of Zoology
. Retrieved
26 August
2012
"Sea stars"
. Wild Singapore
. Retrieved
4 February
2013
External links
edit
Wikimedia Commons has media related to
Echinodermata
Wikispecies
has information related to
Echinodermata
echinobase.org
The Echinoid Directory
from the
Natural History Museum
Echinodermata
from the
Tree of Life Web Project
Echinoderms of the North Sea
Archived
13 April 2008 at the
Wayback Machine
Larval Echinodermata Fact Sheet
Extant
animal
phyla
Domain
Archaea
Bacteria
Eukaryota
(major groups
Metamonada
Discoba
Diaphoretickes
Hacrobia
Cryptista
Rhizaria
Alveolata
Stramenopiles
Plants
Amorphea
Amoebozoa
Opisthokonta
Animalia
Fungi
Mesomycetozoea
Animalia
Porifera (sponges)
Ctenophora (comb jellies)
ParaHoxozoa
Planulozoa
Placozoa (
Trichoplax
and relatives)
Cnidaria (jellyfish and relatives)
Bilateria
(Triploblasts)
(see below↓)
The
phylogeny
of the animal root
is disputed
; see also
Eumetazoa
Benthozoa
Bilateria
Bilateria
Xenacoelomorpha (acoels and relatives)
Chordata (vertebrates and relatives)
Ambulacraria
Echinodermata (starfish and relatives)
Hemichordata (acorn worms and relatives)
Protostomia
Ecdysozoa
Scalidophora
Kinorhyncha (mud dragons)
Priapulida (penis worms)
N+L+P
Nematoida
Nematoda (roundworms)
Nematomorpha (horsehair worms)
L+P
Loricifera (corset animals)
Panarthropoda
Onychophora (velvet worms)
Arthropoda (insects and relatives)
Tardigrada (waterbears)
Spiralia
Gnathifera
Chaetognatha (arrow worms)
Gnathostomulida (jaw worms)
M+R
Micrognathozoa
(Limnognathia)
Rotifera (wheel animals inc. acanthocephalans)
Platytrochozoa
R+M
Rouphozoa
Platyhelminthes (flatworms)
Gastrotricha (hairybacks)
Mesozoa
Orthonectida
Dicyemida or Rhombozoa
Monoblastozoa (
Salinella
Lophotrochozoa
Cycliophora (
Symbion
Annelida (earth worms and relatives)
M+K
Mollusca (snails and relatives)
Kryptotrochozoa
Nemertea (ribbon worms)
Lophophorata
Bryozoa s.l.
Entoprocta or Kamptozoa
Ectoprocta (moss animals)
Brachiozoa
Brachiopoda (lamp shells)
Phoronida (horseshoe worms)
The
phylogeny
of Bilateria
is disputed
; see also
Nephrozoa
Deuterostomia
Xenambulacraria
Centroneuralia
Major groups
within phyla
Sponges
Demosponges
Glass sponges
Calcareous sponges
Cnidarians
Anthozoans inc. corals
Medusozoans inc. jellyfish
Myxozoans
Chordates
Lancelets
Tunicates
Vertebrates
Echinoderms
Sea lilies
Asterozoans inc. starfish
Echinozoans inc. sea urchins
Hemichordates
Acorn worms
Pterobranchs
Nematodes
Chromadorea
Enoplea
Secernentea
Arthropods
Chelicerates inc. arachnids
Myriapods
Pancrustaceans inc. hexapods
Rotifera
Bdelloidea
Monogononta
Seisonidae
Acanthocephala
Platyhelminths
Turbellaria
Trematoda
Monogenea
Cestoda
Ectoproctans
Phylactolaemata
Stenolaemata
Gymnolaemata
Annelids
Polychaetes
Clitellata
Sipuncula
Molluscs
Gastropods
Cephalopods
Bivalves
Chitons
Tusk shells
Phyla with ≥1000 extant species
bolded
Potentially
dubious phyla
Extant
life
phyla/divisions by domain
Bacteria
Abditibacteriota
Acidobacteriota
Actinomycetota
Aquificota
Armatimonadota
Atribacterota
Bacillota
Bacteroidota
Balneolota
Caldisericota
Calditrichota
Chlamydiota
Chlorobiota
Chloroflexota
Chrysiogenota
Coprothermobacterota
Cyanobacteriota
Deferribacterota
Deinococcota
Dictyoglomerota
Elusimicrobiota
Fibrobacterota
Fidelibacterota
Fusobacteriota
Gemmatimonadota
Kiritimatiellota
Lentisphaerota
Minisyncoccota
Mycoplasmatota
Nitrospinota
Nitrospirota
Planctomycetota
Pseudomonadota
Rhodothermota
Spirochaetota
Synergistota
Thermodesulfobacteriota
Thermomicrobiota
Thermotogota
Verrucomicrobiota
Vulcanimicrobiota
Acetithermota
Aerophobota
Auribacterota
Babelota
Binatota
Bipolaricaulota
Caldipriscota
Calescibacteriota
Canglongiota
Cloacimonadota
Cosmopoliota
Cryosericota
Deferrimicrobiota
Dormiibacterota
Effluvivivacota
Electryoneota
Elulimicrobiota
Fermentibacterota
Fervidibacterota
Goldiibacteriota
Heilongiota
Hinthialibacterota
Hydrogenedentota
Hydrothermota
Kapaibacteriota
Krumholzibacteriota
Kryptoniota
Latescibacterota
Lernaellota
Lithacetigenota
Macinerneyibacteriota
Margulisiibacteriota
Methylomirabilota
Moduliflexota
Muiribacteriota
Nitrosediminicolota
Omnitrophota
Parcunitrobacterota
Peregrinibacteriota
Qinglongiota
Rifleibacteriota
Ryujiniota
Spongiamicota
Sumerlaeota
Sysuimicrobiota
Tangaroaeota
Tectimicrobiota
Tianyaibacteriota
Wirthibacterota
Zhuqueibacterota
Zhurongbacterota
Archaea
Methanobacteriota
Microcaldota
Nanobdellota
Promethearchaeota
Thermoproteota
Aenigmatarchaeota
Altarchaeota
Augarchaeota
Geoarchaeota
Hadarchaeota
Hadesarchaeota
Huberarchaeota
Hydrothermarchaeota
Iainarchaeota
Micrarchaeota
Nanohalarchaeota
Nezhaarchaeota
Parvarchaeota
Poseidoniota
Undinarchaeota
Eukaryote
Protist
Amoebozoa
Anaeramoebae
Apicomplexa
Bigyra
Bigyromonadea
Caelestes
Cercozoa
Charophyta
Chlorophyta
Chromerida
Ciliophora
Cryptista
Dinoflagellata
Endomyxa
Euglenozoa
Fornicata
Glaucophyta
Haptophyta
Hemimastigophora
Malawimonada
Nebulidia
Nibbleridia
Ochrophyta
Preaxostyla
Heterolobosea
Hyphochytriomycota
Oomycota
Parabasalia
Perkinsozoa
Picozoa
Retaria
Rhodelphidia
Rhodophyta
Telonemia
Fungi
Chytridiomycota
Blastocladiomycota
Neocallimastigomycota
Glomeromycota
Zygomycota
Ascomycota
Basidiomycota
Land plant
Bryophyta
Marchantiophyta
Anthocerotophyta
Lycopodiophyta
Pteridophyta
Cycadophyta
Ginkgophyta
Pinophyta
Gnetophyta
Animal
Porifera
Ctenophora
Placozoa
Cnidaria
Xenacoelomorpha
Chordata
Hemichordata
Echinodermata
Chaetognatha
Kinorhyncha
Loricifera
Priapulida
Nematoda
Nematomorpha
Onychophora
Tardigrada
Arthropoda
Platyhelminthes
Gastrotricha
Orthonectida
Dicyemida
Rotifera
Acanthocephala
Gnathostomulida
Micrognathozoa
Cycliophora
Nemertea
Phoronida
Bryozoa
Entoprocta
Brachiopoda
Mollusca
Annelida
Incertae sedis
Parakaryon
Relate:
Extraterrestrial life
Taxon identifiers
Echinodermata
Wikidata
Q44631
Wikispecies
Echinodermata
ADW
Echinodermata
AFD
Echinodermata
BioLib:
14962
BOLD
EoL
1926
EPPO
1ECHIP
GBIF
50
iNaturalist
47549
IRMNG
158
ITIS
156857
NBN
NHMSYS0021054038
NCBI
7586
NZOR:
31f21a6e-371d-42b9-868c-569f2249ab4a
Open Tree of Life
451020
Paleobiology Database
30739
WoRMS
1806
Authority control databases
International
GND
National
United States
France
BnF data
Japan
Czech Republic
Spain
Israel
Other
Yale LUX
Retrieved from "
Categories
Echinoderms
Aquatic invertebrates
Extant Cambrian first appearances
Marine animals
Hidden categories:
Articles with short description
Short description is different from Wikidata
Good articles
Use dmy dates from June 2020
Use British English from June 2022
All Wikipedia articles written in British English
Articles with 'species' microformats
CS1 maint: location missing publisher
CS1 maint: multiple names: authors list
Commons link is locally defined
Webarchive template wayback links
Echinoderm
Add topic