Chapter 20 – Crustaceans

50 fill-in-the-blank flashcards covering morphology, physiology, development, taxonomy, and special adaptations of crustaceans.

The Latin root that gives crustaceans their name is __.

crusta

Approximately __ described species of crustaceans are known.

67,000

A typical crustacean possesses __ pairs of antennae.

two

Crustaceans have one pair of mouthparts called __.

mandibles

Most crustaceans bear __ pairs of maxillae.

two

Many crustaceans have a hard dorsal covering called the __.

carapace

Legs that branch into two parts are described as __.

biramous

When present, crustacean respiratory organs are __.

gills

Fusion of certain thoracic segments with the head forms the __.

cephalothorax

The crustacean cuticle is composed of chitin, protein, and .

calcium carbonate

The dorsal plate covering an unfused segment is called a __.

tergum

The ventral transverse bar of a segment is the __.

sternum

The basal portion of a limb in crustaceans is the __.

protopod

The lateral branch of a biramous limb is known as the __.

exopod

The medial branch of a biramous limb is called the __.

endopod

A specialized exite modified as a gill is termed an __.

epipod

The tail fin of many crustaceans is made of paired structures called __.

uropods

The main body cavity of crustaceans is a __ filled with hemolymph.

hemocoel

Muscles that draw appendages toward the body are called __.

flexors

Muscles that extend an appendage outward are the __.

extensors

Small crustaceans exchange gases across thin areas of the __.

cuticle

Crustacean blood circulation operates in an __ system.

open

The chief propulsive organ for hemolymph is the __ heart.

dorsal

Excretory organs that open at the base of the antennae are __ glands.

antennal

Inside each excretory gland is a spongy mass called the __.

labyrinth

The crustacean brain consists of paired __ ganglia.

supraesophageal

Compound eyes are built from photoreceptive units called __.

ommatidia

Balance organs containing statoliths are known as __.

statocysts

The ancestral larval form common to many crustaceans is the __.

nauplius

Shedding of the old cuticle in crustaceans is called __ (or molting).

ecdysis

The outermost lipid-impregnated layer of the cuticle is the __.

epicuticle

The bulk of the crustacean cuticle is formed by the __.

procuticle

Periods between molts are referred to as __.

instars

Molting begins when release of __ inhibiting hormone from the X-organ stops.

molt

The Y-organs near the mandibles secrete the __ hormone that triggers molting.

molting

Male secondary sexual traits are produced by __ glands.

androgenic

In crayfish, food is ground further in the stomach’s .

gastric mill

The mantis shrimp has a specialized digit used to __ or smash prey.

pierce

The __ shrimp’s snapping chela generates the second-fastest animal motion recorded.

pistol

Branchiopods breathe using flattened, leaflike legs called __.

phyllopodia

Adult copepods lack a __ and keep their nauplius eye.

carapace

Barnacles (Cirripedia) possess the longest __ relative to body size of any animal.

penis

Isopods are dorsoventrally flattened and notably lack a __.

carapace

Amphipods differ from isopods by being compressed __.

laterally

Many krill (Euphausiacea) are bioluminescent thanks to an organ called a __.

photophore

Members of the order Decapoda have __ pairs of walking legs.

five

The largest known arthropod is the Japanese spider crab, reaching about __ meters span.

four

Tongueworms belong to Subclass __ and parasitize vertebrate lungs.

Pentastomida

Nauplii of Maxillopoda possess a unique median eye called the __ eye.

maxillopodon

The lateral shell plates of barnacles are secreted by the __.

carapace

In crustaceans, nitrogenous waste is chiefly excreted across the __ and gills.

cuticle