Crustaceans - an introduction

INTRODUCING the ARTHROPOD

CRUSTACEANS with species from southern California ROBERT PERRY Malibu High School & UCLA Ocean GLOBE

Pleuroncodes planipes

ABOUT THE COVER PHOTOGRAPH:

The pelagic red crab, Pleuroncodes planipes

Pelagic red crabs are occasional planktonic visitors from the south.

Pleuroncodes larva Pleuroncodes planipes

DISTRIBUTION OF Pleuroncodes planipes

They are often so abundant that they completely fill our trawls.

Pleuroncodes planipes

Pleuroncodes planipes

Commercial fishing for Pleuroncodes sp.

Phylum

ARTHROPODA Over 923,000 different species !!!!!!!!  Arthropods have an external skeleton (exoskeleton) that covers the entire outer surface of the body. “Arthro” “pod” means ‘jointed-legs.’  Must shed exoskeleton to grow.

eukaryotes

porifera

ANIMALS

THE ANIMAL KINGDOM

cnidaria platyhelminthes

bryozoa arthropoda mollusca

annelida echinodermata

cho r

d at

a Animal cladogram based on DNA sequencing From National Museum of Natural History http://www.amnh.org/exhibitions/hall_tour/spectrum/graphics/cladogram.gif

Phylum Arthropoda.

P h y lu m ARTHRO PO DA IN S E C T S

The most diverse group of animals on earth, but, alas! not in the ocean.

S P ID E R S

Don’t live in the ocean.

“Arthro” “pod” means ‘jointed-legs.’

Arthropods have an external skeleton that covers the entire outer surface of the body.

C la s s CRUSTACEA

Crabs, lobsters, barnacles, copepods, etc.

Class

CRUSTACEA

From the Latin, Crustaceus, meaning soft (refers to soft shell after moulting).

Mostly aquatic arthropods with 2 pairs of post-oral antennae.

Cancer antennarius

Phylum Arthropoda:

Class Crustacea

Benthic sand crab Benthic isopod

Planktonic copepod shrimp

Benthic barnacles

CRUSTACEANS MOULT THEIR SHELLS TO GROW

Panulirus interruptus

Graph - R. Perry

BRANCHIOPODA

Animation from Microscopy UK – Water Fleas http://www.microscopy-uk.org.uk/mag/artjun99/wflea.html

Branchiopod cladocerans are found in freshwater and seawater.

They are often called “water fleas.� The most common genera we find are Podon and Evadne.

Evadne sp.

Cladocerans brood their young under their carapace until they are mature.

Arthropoda/Crustacea:

CIRRIPEDIA Cirri = tiny fingerlike hairs Pedia = on their legs

Barnacles are like tiny shrimps lying on their backs inside an outer shell, kicking food into their mouths.

Balanus spp.

Balanus spp.

Balanus tintinabulum and Tetraclita squamosa attached to wooden pier pilings, on the Santa Monica Pier.

Human consumption of barnacles - “Seaparrot.”

Barnacle eggs hatch as planktonic nauplius larvae. All crustaceans undergo a nauplius stage as their first stage of development.

Pollicipes polymerus

“Gooseneck� barnacles, Pollicipes polymerus, seen close-up Extending their legs to feed. Attached to the Santa Monica Pier.

Arthropoda/Crustacea:

COPEPODA Copepod ( Kope = Greek for "oar" Podos = Greek for "foot")

- Images and text from the Smithsonian Institute http://www.nmnh.si.edu/iz/copepod/

3D computer generated model. http://jaffeweb.ucsd.edu/pages/celeste/Stills/StillBottomOblique.jpg

After Marshall & Orr (1972)

eye Primary antenna

maxilla

Thoracic limb

abdomen

Calanoid copepod – right lateral view

Tiny planktonic copepods are the most abundant animal in the sea. Their biomass exceeds that of all other animals combined.

Copepods swim by moving their primary antennae down, similar to the breast stroke.

Calanoid copepod – dorsal view

Water flow fields created by a calanoid copepod. Note the strongest fields are around the mouth. These are the feeding currents.

Mouth region of Euchaeta, a large carnivorous copepod that rakes in smaller species of copepods.

Cyclopoid copepod females lateral brood view their eggs on their abdomen. dorsal view

Some copepods are parasitic on fish and mammals.

dorsal view Robert Perry

Smithsonian Institute

MALACOSTRACA

Diver with “spider crab” Loxorhyncus grandis

The author, on a night dive with the “sheep crab” Loxorhynchus grandis.

Loxorhyncus grandis

Human consumption of Loxorhynchus grandis

Another species, Loxorhynchus crispatus, “decorates” is own shell with sessile benthic organisms. This species has tiny microscopic hooks that project from its shell. The crab “hooks” bits of seaweed and other debris all over its dorsal surface. In this photograph, bryozoan colonies and a red anemone have been attached.

Loxorhyncus crispatus

Unfortunate L. grandis entangled in a gill net – Channel Islands National Marine Sanctuary, Anacapa Island.

This is known as “by-catch.”

Loxorhyncus grandis

Cancer magister

Many malacostracans are good to eat !

Cancer magister, San Francisco Fisherman’s Wharf.

Human consumption of Cancer anternnarius etc.

Cancer antennarius

CARAPACE ON CEPHALOTHORAX REGION

ABDOMEN (PLEON)

PRIMARY ANTENNA EYE

SECONDARY ANTENNA

THORACIC LIMB 1.

CHELA

MANDIBLE

MOUTH MAXILLA

TL 2.

TL 3.

Cancer antennarius

ABDOMEN (PLEON)

TL 4.

TL 5.

Crab females brood thousands of eggs under their abdomen.

Cancer antennarius

Crab zoea larvae have spikes on their nose and head.

DEVELOPMENT IN ANOTHER DECAPOD: Blepharipoda occidentalis

VENTRAL SIDE OF FEMALE WITH EGG MASS

CLOSE VIEW OF EGG MASS

CLOSER VIEW OF EGG MASS AT AN EARLY STAGE OF DEVELOPMENT

CLOSER VIEW OF EGG MASS AT A LATER STAGE OF DEVELOPMENT

EXTREME VIEW OF EGG MASS AT AN EARLY STAGE OF DEVELOPMENT

EXTREME VIEW OF EGG MASS AT A LATER STAGE OF DEVELOPMENT

CLOSER VIEW OF EGG MASS AT A LATER STAGE OF DEVELOPMENT - BACKLIGHT

VIEW OF NEWLY HATCHED MASSES OF ZOEA LARVAE

VIEW OF NEWLY HATCHED ZOEA LARVAE AND LATE EMBRYONIC EGG STAGE

ZOEA

LATE EMBRYO

ZOEA LARVAE

ZOEA LARVAE (COMPOSITE IMAGE OF FRONT AND BACK LIGHTING)

CALIFORNIA SPINY LOBSTER

Many crustaceans are good to eat.

The california spiny lobster, Panulirus interruptus, was once so abundant that these men captured them in the tide pools.

Panulirus interruptus

The California spiny lobster, Panulirus interruptus, at home on a rocky subtidal reef.

Panulirus interruptus

Note the two pairs of pre-oral antennae !

In the spring, males transfer a gummy sperm packet to the underside of the female.

Panulirus interruptus

During the summer, when lobster season is closed, the females use the sperm packet to fertilize thousands of orange eggs, which are kept under her pleopods.

Panulirus interruptus

The eggs hatch out as planktonic phyllosoma larvae and drift away.

x40

3 mm

Panulirus interruptus

Licensed lobster boats set traps in rocky subtidal areas. Their traps are marked by floating buoys.

On the bottom, the lobster traps provide a one-way entrance.

Panulirus interruptus

Human consumption of lobster: WEST COAST

Simple, tastey lobster tails full of delicious meat.

EAST COAST

Messy, tedious, picking and cracking and sucking to get the meat.

Human consumption of Panulirus interruptus:

Panulirus interruptus

THE END Please direct all comments to perry@smmusd.org