1. Study Unit/Leergedeelte 1.2
Phylum/filum: Echinodermata
Class/klas: Echinoidea,
Holothuroidea, Crinoidea
Note: all pictures, unless otherwise stated, are copyright of the McGraw-Hill
Companies, Inc. Permission required for reproduction or display.
2. Phylum/Filum: Echinodermata
Class/Klas: Echinoidea
Sea Urchins
Seekastaaing
• Approximately 950 species
• Ongeveer 950 spesies
• No arms, show five-part symmetry
• Geen arms. Wel 5 streke
• Up-folding - ambulacral areas up to the
anus
• 5 Streke opgebuig om by anus
bymekaar te kom
• Hemispherical, radial symmetry and
long spines
• Hemisfeer, radiaal simmetries, lang
stekels
• Sand dollars flattened with short
spines
• Sand dollars afgeplat met kort stekels
• Move by tube feet
• Beweeg met buisvoete
4. Class/Klas: Echinoidea
Sea Urchins
Seekastaaing
• 10 double rows of plates with movable, stiff spines
• 10 dubbel rye plate met beweegbare stewige
penne
• Spines articulate on “ball-and-socket” joints –
muscles
• Penne artikuleer op bol-gewrig met spiere
• Tube feet extend along the 5 ambulacral rows,
extending out through pores
• Buisfoete versprei langs die 5 ambulakraalrye
P 1
I
P 2
II
P 3
III
P 4
IV
P 5
V
5. Class/Klas: Echinoidea
Sea Urchins
Seekastaaing
• Some species have pedicellariae with poison glands
• Sommige het pedisillaria met gifkliere
• 5 converging teeth and sometimes branched gills encircle the
peristome
• Peristoom omring deur 5 tande en soms vertakte kieue
6. Class/Klas: Echinoidea
Sea Urchins
Seekastaaing
• Mouth is part of a structure called the Aristotle’s
lantern
• Mond genoem die Aristotole Lantern
• Omnivorous, but feed largely on algae
• Omnifoor eet meetstal alge
• Sand dollars filter particles through spines
• Sand dollars filter kosdeeltjies deur stekels
7. Class/Klas: Echinoidea
Sea Urchins
Seekastaaing
• Anus, genital pores, and madreporite = aboral
• Anus, geslagsopening en madreporiet = aboraal
• In Sand dollars the anus shifted to the posterior
• In sand dollars het die anus na agter geskuif http://treatment.plazi.org/id/038087B4-
FFB7-896B-FF02-FD48708E9B51
8. Class/Klas: Echinoidea
Sea Urchins
Seekastaaing
• Reproduction/Voortplanting:
• Sexes are separate
• Eenslagtig
• Gametes are shed into sea for external fertilization
• Gamete vrygestel in water
• Some, including pencil urchins, brood young in
depressions between the spines
• Sommige soos die sigaarskulpe inkubeer kleintjies
tussen penne
• Others have Echinopluteus larvae that live a
planktonic existence before becoming urchins
• Ander het ‘n echinopluteus larwe wat planktonies
leef
See: https://www.youtube.com/watch?v=McoTIKU1bf0 (sea urchin)
https://www.youtube.com/watch?v=KeIvSE5S2yQ (sea biscuit/sand
dollar)
9. Class/Klas: Holothuroidea
Sea Cucumbers
Seekomkommer
• Approximately 1150 species
• Ongeveer 1150 spesies
• Resemble cucumbers
• Lyk soos komkommers
• Few ossicles - body is soft
• Min ossikels – liggaam sag
• Some species crawl on the ocean bottom, others are
found under rocks or burrow
• Sommige op seevloer, ander op rotse en rotsskeure
https://pxhere.com/en/photo/718795
https://twitter.com/Piper_Thibodeau/status/644343604480200704/
photo/1
10. Class/Klas: Holothuroidea
Sea Cucumbers
Seekomkommer
• Body wall is leathery
• Vel leeragtig
• In some, tube feet distributed to 5 ambulacral areas
• In sommige is buisvoete in 5 ambulakraalstreke
• Most have them only on the 3 ambulacra that face the substratum
• Meeste het egter net buisvoete op die drie ventrale ambulakraalstreke
• Tube feet absent in burrowing forms
• Buisvoete afwesig in grawende spesies
• Oral tentacles are modified tube feet
• Oraaltentakels is gemodifiseerde buisvoete
https://www.flickr.com/photos/65695019@N07/8456845410
https://commons.wikimedia.org/wiki/
File:Neothyonidium_magnum_(Burrowing_sea_cucumber)_at_
night.jpg
11. Class/Klas: Holothuroidea
Sea Cucumbers
Seekomkommer
• Use ventral tube feet and body waves to move
• Beweeg deur liggaamsbewegings en buisvoete
• Some graze on sea floor, others trap food in tentacles. Others
graze sea bottom with tentacles
• Sommige voed op seebodem – ander vang kos in tentakels vas
See: https://www.youtube.com/watch?v=sEqJQ1ysGdQ
(Sea Pig)
https://commons.wikimedia.org/wiki/File:Scotoplanes_globosa_and_crab.jpg
12. Class/Klas: Holothuroidea
Sea Cucumbers
Seekomkommer
• Coelomic cavity has many coelomocytes
• Baie selomosiete in seloom
• Respiratory tree in cloaca
• Respiratoriese stelsel in die kloaak
• Madreporite lies free in the coelom
• Madreporiet in seloom
• Respiratory tree also serves for
excretion
• Respiratorsiese stelsel ook vir
uitskeiding
• Gas exchange also occurs through the
skin and tube feet
• Gaswisseling ook deur vel
13. Class/Klas: Holothuroidea
Sea Cucumbers
Seekomkommer
• Cast out part of viscera when irritated. Regenerate
• Spoeg deel van ingewande uit as bedreig word. Regenereer
• Small fish, Carapus, shelter in cloaca
• Klein vissie Carapus leef in kloaak
• See: https://www.youtube.com/watch?v=giA16BoH_no
https://www.flickr.com/photos/animaliaproject/6517706799/
sizes/z/
14. Class/Klas: Holothuroidea
Sea Cucumbers
Seekomkommer
• Reproduction/Voortplanting:
• Sexes are separate in most
• Meeste eenslagtig
• Some hermaphroditic
• Sommige hermafrodities
• Single gonad – primitive
• Enkele gonade – primitief
• Fertilization is external – free-swimming auricularia
• Bevrugting uitwendig – Vryswemmende ourikularia
larf
https://www.flickr.com/photos/
nelas/7988737864
15. Class/Klas: Crinoidea
Sea Lilies & Feather Stars
Seelelies & veersterre
• Sea lilies (A) and feather stars (B)
• Seelelies (A) en veersterre (B)
• Primitive
• Primitief
• Numerous in fossil record
• Baie fossiele
• Sessile
• Sessiel
https://www.flickr.com/photos/noaaphotolib/9720863894
A
https://commons.wikimedia.org/wiki/File:Feather_Star_1.jpg
B
• Flower-shaped body
• Blomvormig
• Sea lilies – deep water. Feather stars –
shallow water
• Seelelies –diepwater. Veersterre - vlakwater
16. Class/Klas: Crinoidea
Sea Lilies & Feather Stars
Seelelies & veersterre
• Leathery calcareous
• Leeragtig of kalkagtig
• Five branched arms
• Vyf vertakte arms
• Madreporite, spines, and pedicellariae are
absent
• Geen madreporiet, stekels of pedisillaria nie
17. Class/Klas: Crinoidea
Sea Lilies & Feather Stars
Seelelies & veersterre
• Mouth - esophagus – intestine
• Mond – easofagus – intestinum
• Ambulacral grooves have tube feet and mucous
nets – feeding
• Ambulakraalgroewe met buisvoete en
mukusnette – help met voeding
• Has a water-vascular system, an oral ring, and a
radial nerve to each arm
• Watervatstelsel met oraalring, radiaalkanaal en
radiaalsenuwee in elke arm
18. Class/Klas: Crinoidea
Sea Lilies & Feather Stars
Seelelies & veersterre
• Reproduction/Voortplanting:
• Sexes are separate
• Eenslagtig
• Gonads in arms
• Gonades in arms
• Some brood eggs
• Sommige inkubeer eiers
• Free-swimming doliolaria larvae
• Vryswemmende doliolaria larwe
• Most 15–30 centimeters
• Meeste 15–30 cm lank
• Fossil species up to 20 m
• Fossiele tot 20 m lank https://www.flickr.com/photos/jsjgeology/17389937442
19. Asteroidea Ophiuroidea Echinoidea Holothoroidea Crinoidea
Ambulakraalgroef /
Ambulacral groove
Oop / Open Toe / Closed Opgebuig –
Versmelt / Fused
3 streke ventraal
3 areas ventrally
Vertak / Divided
Pedisillaria /
Pedicilaria
Ja / Yes Geen / None Ja/ Yes Geen/ None Geen/ None
Madreporiet /
Madreporite
Aboraal / Aboral Oraal / Oral Aboraal/ Aboral In seloom / In
coelom
Geen/ None
Papulae Ja/ Yes Geen/ None Geen/ None Geen/ None Geen/ None
Anus Aboraal/ Aboral Geen/ None Aboraal/ Aboral Ja/ Yes Kant van skyf /
Side of disk
Larf / Larva Bipinnaria /
Bipinnaria
Ofiopluteus /
Ophiopluteus
Echinopluteus /
Echinopluteus
Ourikularia /
Auricularia
Doliolaria
