Lab Activity 9.3
Biota 3: Molluscs Found in Tidepools

  Directions

Study the instructional material below. Be sure to click on each of the photographs for an enlarged view in a separate window. The larger version is necessary to complete the assignment. It opens in a separate window which can be resized by grabbing the bottom right corner and dragging it. It can also be moved by grabbing the top heading bar and dragging it. Be sure to close the extra window by using the X in IBM, or the close box in MAC when you are finished using them.

  Introduction


In this lab activity you will study the molluscs of tidepools.

Top  Instruction

Use the information below to fill out the checklist of the biota of tidepool microhabitats.

Be sure to write about what you are learning in the lab section of your notebook. You will be expected to answer questions about the lab activity during the lab self test and lab quiz. It helps to have your text and coloring books open beside you for support.

 
Supporting Information
Refer to the Assigned Readings Below:
Marine Biology Textbook none
Marine Biology Coloring Book none
 

This picture gallery summarizes the molluscs found in tidepools at Playa Estacion, Puerto Penasco, Sonora, Mexico.

It should be used to complete lab activity 9.3.

 

Pinctada mazatlanica

"Pearl oyster"
Phylum  Mollusca
Class  Pelecypoda
Order   Pterioida
Family   Pteriidae

Morphology Shell is heavy, 4 to 5 inches long, brown outside with a flaky periostracum, and with a beautiful, smooth, iridescent, blue inside. Attach to rocks by byssal threads.
Feeding Filter feeding
Defense Not easily removed from rocks. Can tightly close valves.
Reproduction Separate sexes and spawning
Habitat Low intertidal and shallow subtidal rocks in sandy and muddy areas
Distribution Lower Pacific Baja, throughout the Gulf of California, south to Peru
Other Produce pearls and shell is valued for buttons. Over harvesting has closed the commercial pearl industry that once thrived in the Gulf of California.

 

Lima pacifica
"Swimming file shell"
Phylum  Mollusca
Class  Pelecypoda
Order   Pterioida
Family   Limidae
Morphology Long, narrow, textured, white shell to 1.5 inches long. Mantle is fringed by many long tentacles that are visible even when the shells are closed. Lightly attaches to rocks with byssal threads.
Feeding Filter feeding
Defense Capable of swimming by clapping its valves. Sticky tentacles break loose when disturbed.
Reproduction Separate sexes and spawning
Habitat Under subtidal rocks and intertidal tidepool rocks
Distribution Gulf of California to Peru
Other  

 

Turbo fluctuosus

"Turban shell"
Phylum  Mollusca
Class  Gastropoda
Order   Archeogastropoda
Family   Turbinidae
Morphology Top-shaped shell with a heavy calcarous operculum. Color is variable, from bright orange to dark green. Commonly 2.5 inches.
Feeding Grazes on algae.
Defense Closes its shell aperature with a hard, calcareous operculum
Reproduction  
Habitat Abundant on rocky shores.
Distribution Throughout the Gulf of California and south to Peru and Ecuador
Other Operculum is collected for jewelry. Best observed at night.

 

Solenosteira macrospira
"Large-coiled welk"
Phylum  Mollusca
Class  Gastropoda
Order   Neogastropoda
Family   Buccinidae
Morphology Tan to brown; white lips; fibrous periostracum.
Feeding Scavengersthat feed on dead animals
Defense Thick shell
Reproduction Females deposit egg cases on shell of males
Habitat Intertidally on sand and rocks.
Distribution Northern Gulf of California
Other  

 

Aplysia californica

"Sea hare"
Phylum  Mollusca
Class  Gastropoda
Order   Anaspida
Family   Aplysiidae

Morphology Animal mottled brown with green streaks and spots. Body length 6-30 inches. Large humped body and has a dorsal-projecting flap on each side. The small, partly calcified shell is flattened and located embedded in the mantle tissues between the flaps.
Feeding Feeds on various species of red and green algae.
Defense May emit a purple defensive secretion when disturbed.
Reproduction Cross copulating hermaphrodites. Deposit long, tangled skeins of yellow, yellow-green, or pink eggs. Each individual is capable of laying over 750,000 eggs in one season.
Habitat Subtidal rocks and rocky tidepools
Distribution Northern California to the northern Gulf of California.
Other  

 

Berthellina ilisima
"Apricot slug"
Phylum  Mollusca
Class  Gastropoda
Order   Notaspidea
Family   Pleurobranchidae
Morphology A smooth, uniformly orange slug with two antennae on its head. It has a small internal shell and a gill located under the mantle on the right side of the body. Up to 2.5 inches long.
Feeding Feeds on cnidarians especially anemones
Defense Skin secretes defensive sulfuric acid.
Reproduction Hermaphroditic. Deposits eggs on rocks or seaweeds as pale orange masses laid in wide, spiral ribbons.
Habitat Subtidal rocks and rocky tidepools
Distribution Throughout the Gulf of California
Other  

 

Tridachiella diomedea
"Mexican dancer"
Phylum Mollusca 
Class  Gastropoda
Order   Sacoglossa
Family   Elysiidae
Morphology Light black or blackish green, shelless slug with frilled mantle margins and with two antennae on its head. They are very colorful, often with blue, purple and orange markings. Up to 2 inches long.
Feeding Feeds on seaweed and green algae and retains symbiotic chloroplasts in its tissues.
Defense Unpalatable
Reproduction Hermaphroditic
Habitat Subtidal rocks and rocky tidepools
Distribution Gulf of California to Panama
Other  

 

Hypselodoris californiensis
"Blue and gold nudibranch"
Phylum  Mollusca
Class  Gastropoda
Order   Nudibranchia
Family   Chromodorididae
Morphology Dark blue, shelless slug with a circlet of gills on its back and two antennae on its head. They have bright yellow spots and iridescent sky-blue stripes. Up to 2.5 inches long.
Feeding Grazes on colonial invertebrates
Defense Unpalatable
Reproduction Hermaphroditic
Habitat Subtidal rocks and rocky tidepools
Distribution Central California, throughout the Gulf of California and south to southern Mexico
Other  

 

Glossodoris sedna
"Sedna nudibranch"
Phylum  Mollusca
Class  Gastropoda
Order   Nudibranchia
Family   Chromodorididae
Morphology White, shelless slug with a circlet of gills on its back and two antennae on its head. Three stripes encircle the foot: one white, one yellow, and one red. The gills and antennae are tipped in red. Up to 2.5 inches long.
Feeding Graze on sponges
Defense Defensive terpene secretions similar to metabolites of prey sponges
Reproduction Hermaphroditic
Habitat Subtidal rocks and rocky tidepools
Distribution Lower Pacific Baja and throughout the Gulf of California
Other  


Lab Activity 9.3 Biota 2