CLASS POLYPLACOPHORA
- Habitat: The Class Polyplacophora contains the Chitons. Chitons live on hard substrates in shallow marine water. Early Native Americans ate Chitons. ...
- Body Parts: Chitons have a reduced head, a flattened foot, and a shell. ...
- Locomotion: Chitons crawl over their substrate like gastropods. ...
- Gills and mantle Cavity: A linear series of gills are present in the mantle cavity on each side of the foot. ...
What is an example of polyplacophora?
The class Polyplacophora extends back to the Late Cambrian Period with the early genus Matthevia. Some fossil species had only seven plates. Examples of the order Paleoloricata are found from the Late Cambrian through the Late Cretaceous.
What is a Polyplacophora chiton?
Chitons are distinct in possessing eight (sometimes seven) overlapping transverse shell plates (hence, the name Polyplacophora, which means "bearer of many plates") that permit the ovoid, dorsoventrally reduced body to conform to the irregular, rocky shores on which they are most often found.
What happens to the eggs of polyplacophora?
Once the eggs are fertilized, they become free-swimming larvae and then turn into a juvenile chiton. Here are a few more facts that we know about Polyplacophora: The word is pronounced poly-plac-o-for-a. Chitons are also referred to as sea cradles or "coat-of-mail shells."
What is the difference between polyplacophora and Neoloricata?
The class Polyplacophora extends back to the Late Cambrian Period with the early genus Matthevia. Some fossil species had only seven plates. Examples of the order Paleoloricata are found from the Late Cambrian through the Late Cretaceous. The order Neoloricata extends from the present back to the Mississippian Period.
What are characteristics of chitons?
Chitons are flattened, elongately-oval, with eight overlapping dorsal shell plates or valves, bordered by a thick girdle formed from the mantle that may be covered with spines, scales, or hairs.
What is unique about the class Polyplacophora?
Polyplacophorans are a class of the phylum Mollusca and are commonly known as Chitons. They are easily distinguishable from the superficially similar Limpets (which are part of the Gastropoda) by the fact that their shell is composed of eight separate plates, rather than being just one piece.
What are the sensory structures in Polyplacophora?
Osphradium. The osphradium is a chemosensory structure found in most molluscan groups [18]. Within Polyplacophora, the osphradium sensu stricto is a pigmented sensory stripe in the roof of the pallial cavity between the anus and the first (posterior-most) gill ([19], p. 427).
What type of animal is in class Polyplacophora?
molluscsChitons (/ˈkaɪtənz/) are marine molluscs of varying size in the class Polyplacophora (/ˌpɒlipləˈkɒfərə/), formerly known as Amphineura. About 940 extant and 430 fossil species are recognized.
What are examples of Polyplacophora?
ChitonidaNeoloricataAcanthoch...MopaliidaeChitoninaLepidople...Chitons/Lower classifications
What is the meaning of Polyplacophora?
Definition of Polyplacophora : an order of Amphineura comprising the chitons all of which have the foot occupying the whole ventral surface of the body and the shell composed of eight calcified dorsal plates.
How many eyes do Polyplacophora have?
Their underlying layers seem to be hard and thick, so that any damage doesn't penetrate fully. And chitons have up to 1,000 eyes and can grow more throughout their lifetimes, replacing any that are damaged.
Does Polyplacophora have locomotion?
Chitons move by creeping slowly using the muscular foot for locomotion and adhesion, and their separate, articulating valves allow them to move over and cling tightly to sharply curved or irregular surfaces.
Does Polyplacophora have mantle cavity?
The mantle skirt extends around the whole periphery of the animal as a girdle (Polyplacophora-transverse sec.). The ventral surface is mainly occupied by the muscular foot, which is surrounded by the mantle cavity.
What is the common name for Polyplacophora?
PolyplacophoraCommon NameScientific NameCommon Eastern ChitonChaetopleura (Chaetopleura) apiculataCommon West Indian ChitonChiton (Chiton) tuberculatusCommon West Indian ChitonChiton (Chiton) tuberculatusConcealed Arctic ChitonAmicula vestita157 more rows
Do Polyplacophora have gills?
Contrary to snails, for example, chitons, have no mantle cavity containing gills. Instead, there is a groove running almost all around the animal between mantle and foot containing numerous mollusc-type gills or ctenidia....Chitons (Placophora)ClassSpecies No.Molluscs (Mollusca)55.4009 more rows
Is a radula present in Polyplacophora?
The major lateral radula teeth of chitons (Mollusca:Polyplacophora) are one of the hardest and most wear resistant biomineralized tissues known to date.
Where do polyplacophora live?
They can also live on rocks. Polyplacophora are found in cold waters and in tropical waters. Some live in tidal zones and can hold up to air exposure for periods of time. Others can live as deep as 20,000 feet under the surface of the water. They are only found in salt water.
How do polyplacophora reproduce?
How Polyplacophora Reproduce. There are male and female chitons, and they reproduce by releasing sperm and eggs into the water. The eggs may be fertilized in the water or the female may retain the eggs, which are then fertilized by sperm that enters along with water as the female respires.
Physical Characteristics
Chitons (KI-tons) are flattened mollusks that are egg-shaped in outline. They have eight distinct and overlapping shell plates, or valves, across their backs. The valves are layered, with each layer made up of mostly calcium carbonate. Each valve is usually shaped like a butterfly. A ring of tissue surrounds or sometimes covers the entire body.
Additional topics
Animal Life Resource Mollusks, Crustaceans, and Related Species Chitons: Polyplacophora - Physical Characteristics, Behavior And Reproduction, Gumboot Chiton (cryptochiton Stelleri): Species Accounts, Veiled Chiton (placiphorella Velata): Species Accounts - GEOGRAPHIC RANGE, HABITAT, DIET, CHITONS AND PEOPLE, CONSERVA
How many dorsal plates are there in a mollusk?
Thumbnail description#N#Mollusks with a flattened, ovoid shape, broad ventral foot, and eight (sometimes seven) dorsal shell plates that overlap one another and allow the animal to bend and mold itself onto a rock to avoid wave dislodgement
How deep is the kelp?
Found on rocky shores as well as soft bottoms, in relatively protected sites near deep channels, from the low intertidal zone down to a depth of roughly 70 ft (21.3 m) in kelp beds.
What is the radula used for?
The radula, a chitonous ribbon covered with many rows of hard , recurved teeth, is used for feeding, most frequently on the microalgae that coat the rocks on which chitons are found. In some species, this radula contains iron, part of it as magnetite, the only known example of biological production of this common mineral. Magnetite greatly strengthens the radula, allowing many chitons to feed on hard, encrusted coralline algae.
Is mollusca a nonsegmented phylum?
Nevertheless, other theories currently lean toward a nonsegmented ances tor for the phy lum Mollusca, based on the unsegmented coelom (unlike that of annelids), the lack of agreement in the number of paired organs in basal mollusks (e.g., aplacophorans versus polyplacophorans), and the lack of evidence of segmentation in many other classes within the phylum. These theories support the placement of the aplacophorans, with a vermiform body that lacks a shell (and often lacks a foot, radula, and most gills), as near the base of the phylogenetic tree of mollusks.
What color is a girdle?
Broadly oval 5 cm long, with anterior margin of girdle extended into a flap used to capture small motile prey; valves much shorter than width; color pattern a mixture of green, brown, pink, tan & blue.
What is the synonym of Stenoplax fallax?
Synonyms: Similar species: Stenoplax fallax (Carpenter in Pilsbry, 1892) Phylum Mollusca, Class Polyplacophora, Order Chitonida, Family Ishnochitonidae. Elongate oval 8 cm or more; bottom of foot orange; valves purple to red, speckled with brown or white. Adults on sides of rocks buried in sand; a fast-moving, photonegative chiton.
