-
What is this?
- Chordata
- . . .Tunicata
- . . . . .Ascidacea larva
-
What is this?
- Chordata
- . . .Tunicata
- . . . . .Appendicularia
- . . . . . . . .Oikopleura
-
What is this?
- Echinozoa
- . . .Echinoidea
- . . . . .Sea Urchin
-
What is this?
- Echinoidea
- . . .Clypeasteroida
- . . . . .Echinarachnius parma
-
What is this?
- Holothuroidea
- . . .Sea Cucumber
-
What is this?
- Eleuthozoa
- . . .Asteroidea
-
What is this?
- Hemichordata
- . . .Balanglossus
-
What is this?
- Ophiuroidea
- . . .Brittle Star
-
What is this?
- Ophiuroidea
- . . .Gongoncepahalus
-
What is this?
- Echinodermata
- . . .Crinoidea
- . . . . .Antedon
-
What is this?
- Echinoidea
- . . .Sea Urchin
-
ECHINODERMATA - 6,000 spp
(Echinos, hedgehog; derma, skin)
- Pentamerous symmetry
- Marine and benthic
- Water vascular system- functions in support of locomotory tube feet; important in gas exchange, excretion, and feeding
- Body wall includes a thick connective tissue dermis where calcareous occicles (little bones) are present; the connective tissue is multiple, its consistency is under nervous control
- Ossicles make up an endoskeleton, echinoderm = spiny skin
- Loss of gill slits
-
(Echinodermata) Crinoidea - 700 spp
(Sea Lilies, Feater Stars)
- Common body plan except sea lilies are attached to the bottom by a stalk; feather stars have no perminent attachment
- Radially symmetrical, benthic, suspension feeders
- Crinoids are oriented upside down in comparison with other echinoderms, with their oral urface uppermost
-
Echinodermata (Crinoidea) Antedon (Sea Lily)
- Juveniles are stalked and sessile, adults are capable of active swimming
- During feeding, animal clings to rocks using jointed, aboral cirri while arms are fully extended using tube feet for food collection
- The 5 ambulacral grooves radiate out from the mouth and extend along the middle of the arms
- Arms bear pairs of pinnules
-
ELEUTHEROZOA
- Mobile echinoderms
- Oral surface faces substratum
- Madreporite (controls entry of seawater into vascular system) and tube feet present
- Polian vesicles on the ring canal
- Movable spines
- Includes all recent echinoderms except for sister taxon, Crinoidea
-
(Eleutherozoa) Asteroidea
(Sea Stars)
- The ossicles of the body wall are rodlike and articulate via fibrous junctions to form a flexable grid
- Repiration is with the tube feet and papulae (between ossicles)
- Each arm has a pair of large pyloric ceca, gonads, and an eyespot at the tip
-
Eleutherozoa (Asteroidea) Asterias forbesi (Sea Star)
- 5 arms radiate from the central disk
- Pale, lower side = oral surface
- Dark, upper side = aboral surface
- Madreporite and anus located on aboral surface
- The mouth, surrounded by the thin peristomial membrane, and the stomach (found in the mouth) and the eye can be seen on the oral side of the animal
- 5 deep ambulacral grooves raidiate outward from mouth
-
CRYPTOSYRINGIDA
- Includes Ophiuroidea, Echinoidea, Holothuroidea
- All with closed ambulacra in which radial nerve is internalized and protected by ossicles
- Defining traits: radial nerves are internalized in epineural canal
-
Chyptosyringida (Ophiuroidea) Ophiderma brevispina
(Brittlestar)
- Arms sharply set off from the disk
- They lack ambulacral grooves
- Disctinct separation of the central disc and radial arms (how they differ from Asteroids)
- Oral medreporite
- Vertebral ossicles in arms
- Arm-plate ossicles
- Ophiopluteus larva
-
Chyptosyringida (Ophiuroidea) Gorgoncepahalus
(Basket Star)
- Arms are used for climbing and attachment underwater
- Arms can be flexed in any direction
- Feed at night, usually on a right angle for maximum fishing efficiency
-
Chyptosyringida Echinozoa
(Sea Urchings, Sea Cucumbers)
- Oral surface and ambulacra expanded aborally to cover most of the body (minus anus)
- Ossicles form ring around pharynx
- Ossicles in tube feet
- Suckered tube feet
- Well-developed hemal system with rete mirabile
-
ECHINOIDA - 950 sp
(Sea Urchins, Sand Dollars)
- 2 shapes - spherical, regular (sea urchin) or disk shaped, irregular (sand dollar)
- Test of fused ossicles
- Two skeletal pores for each tube foot
- Aristotles lantern - equiped with 5 long teeth used for scrapping food off hard substrates
- Polian vesicles lost
- Echinopluteus larva
-
Echinozoa Echinoidea (Strongylocentrotus drobachiensis)
(Green Sea Urchin)
- Most of the surface bears articulates, movable spines
- Spines can be moved in any desired direction, with an effective locking system that makes them impossible to move without breaking them first
- 10 meridional rows of long, slender tube feet (or podia)
- Most tube feet end in wide suckers, used for locomotion and respiration
- Peristome - peri = around, stome = mouth
-
CLYPEASTEROIA - Flattened Urchins
(Sand Dollars and Sea Biscuits)
- Adapted for living and moving in soft sediments
- Irregular urchins, tend to be elongate and slightly streamlines along an axis perpendicular to the oral-aboral axis (to help move through soft sediments)
-
Clypeasteroida Clypeaster rosaceus (Sea Biscuit), Echinarachinus parma (Sand Dollar)
- Clypeaster rosaceus:
-
Thick body, not thin like a sand dollar - Uses short spines of its oral surface to pole its way across the sand
- Suckered tube feet on aboral surface (holds debris on it for camoflauge)
- Echinarachinus parma:
- Tube feet involved in gas exchange, they are specialized gills with enhanced surface area, not used for locomotion, do not have suckers and are not tubular
- Openings in shells are called lunnules
- Much simpler Aristotles lantern than Urchins, 5 jaws holding 5 teeth, pyramids (doves)
-
Echinodermata Holothuroidea
- Minute ossicles in thick dermis
- Body wall musculature in 5 longitudina bands
- microphagus, retractable buccal podia
- repiratory trees
-
Echinodermata (Holothuroidea) Cucumaria frondosa
(Sea Cucumber)
- The oral end bears a mouth and a circle of ten branched tentacles, the buccal podia (introvert - can be fully retracted into the body)
- Ventral surface has better developed tube feet, known as locomotory podia, for "creeping"
-
HEMICHORDATA
(Acord Worms and Sea Angels)
- Dorsal and ventral longitudincal nerve cords
- Stomochord antagonizes contractile pericardium
- Valved collar ducts
- Muscular locomotory-secretory protosome
-
Hemichordata (Enteropneusta) Balanoglossus
Acorn Worm
- Burrowing animals that live in mucous lines, U-shaped burrows in soft sand
- Essentially sessile but can move to excrete waste out the hole of their burrow
- Proboscis used todig new burrows
-
CHORDATA
- Dorsal, hollow nerve cord with open anterior neuropore
- Notocord
- Pharynx with endostyle
- Ventral postoral heart
- Fins
- Cross-straited longitudinal muscles for swimming
-
Chordata (Tuicata) Ascidiacea
(Sea Squirts)
- Tunic
- Buccal tentacles
- Heartbeat reveral
- Neural gland ventral to the cerebral ganglion
- Pyloric gland
- Hermaphroditic
- Tubular notocord with extracellular lumen
- Bilateral cleavage
- Determinate development
-
Tunicata (Appendicularia) Oikopleura
- Look like "tadpoles"
- Keep their tale all their life
- Only Tunicates to have all of the key chordate characteristics as adults
- Secretes a house around itself that captures food as water is drawn through the system by tail lashingd
|
|
