Download Appendages

CHAPTER 20
Crustaceans
20-1
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
20-2
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Overview




Over 67,000 living species
Insects and crustacea compose over 80% of
all named animal species
Probably most abundant animals in the world
are members of the copepod genus Calanus
Divided into 5 classes


20-3
Current molecular phylogenies do not support the
monophyly of all classes
Former members of phylum Pentastomida
placed in class Maxillopoda, subclass
Pentastomida
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
20-4
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Overview

Pentastomids



20-5
Also called tongue worms
Parasites of vertebrates, living in lungs or nasal
cavities
Closely related to fish lice
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Subphylum Crustacea
General Nature of a Crustacean

Main distinguishing characteristic of
crustaceans



Two pairs of antennae
Head also has a pair of mandibles and 2 pairs
of maxillae
One pair of appendages on each of the
additional segments


20-6
Some segments may lack appendages
All appendages, except perhaps first antennae, are
biramous
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Subphylum Crustacea


Primitive crustaceans may have up to 60
segments; derived crustaceans have fewer
Tagmata are usually head, thorax, and abdomen



Not homologous across taxa
In most one or more thoracic segments are
fused with the head as a cephalothorax
Arrangement of tagmata in Malacostraca is the
ancestral plan



20-7
Head has 5 fused somites
Thorax has 8
Abdomen has 6
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
20-8
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Subphylum Crustacea



Anterior end is a non-segmented rostrum
Telson, with the last abdominal somite and
uropods, forms a tail
Dorsal covering is the carapace

20-9
May cover most of body or just cephalothorax
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Subphylum Crustacea
Form and Function

External Features


Secreted cuticle is made of chitin, protein, and
calcareous material
Heavy plates have more calcareous deposits



Dorsal tergum and ventral sternum are plates on
each somite lacking a carapace
Telson is not a somite



20-10
Joints are soft and thin, allowing flexibility
Bears anus and may be homologous to the pygidium
In some species, telson may bear a pair of
processes, the caudal furca
Gonopores may be at base of appendages, at the
tail, or on somites without legs
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
20-11
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Subphylum Crustacea

Appendages






Members of Malacostraca and Remipedia have
appendages on each somite
Other classes may not bear appendages on
abdominal somites
Specialization of appendages based on the basic
biramous plan
Maxilliped has a basal protopod, a lateral exopod,
and a medial endopod
Endites are medial processes, exites are lateral
processes and epipod is an exite on the protopod
Appendages represent serial homology

20-12
Have evolved a wide variety of walking legs, mouthparts,
swimmerets, etc. from modification of the basic biramous
appendage
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
20-13
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
20-14
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
20-15
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Subphylum Crustacea

Internal Features


20-16
Muscular and nervous systems and segmentation
exhibit metamerism of annelid-like ancestors
Hemocoel
 Persistent blastocoel that becomes filled with
blood
 Coelomic compartments remain as end sacs of
excretory organs and gonads
 Coelomates only in technical sense of the term
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Subphylum Crustacea

Muscular System




20-17
Striated muscles
 Make up a major portion of crustacean body
Most muscles arranged as antagonistic groups
 Flexors draw a limb toward the body and
extensors straighten a limb out
Abdominal flexors of a crayfish allow it to swim
backward
Strong muscles located on each side of stomach
control the mandibles
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
20-18
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Subphylum Crustacea

Respiratory System





20-19
Smaller crustaceans may exchange gases across
thinner areas of cuticle
Larger crustaceans use featherlike gills for gas
exchange
Decapod carapace overlaps the gill cavity, leaving
anterior and posterior openings
“Bailer” of 2nd maxilla draws water over gill
filaments
Gills may project from pleural wall, the
articulation of thoracic legs, or thoracic coxae
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
20-20
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Subphylum Crustacea

Circulatory

Open circulatory system




Dorsal heart




20-21
Single-chambered sac of striated muscle
Valves in the arteries prevent backflow of
hemolymph
Hemolymph conducted to gills, if present, for oxygen
and carbon dioxide exchange
Hemolymph may be colorless, reddish, or bluish


No system of veins to separate blood from interstitial fluid
Hemolymph exits heart through arteries
Passes to hemocoel to return to the heart via sinuses
Contains ameboid cells that may help prevent clotting
Hemocyanin and/or hemoglobin are respiratory
pigments
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Subphylum Crustacea

Excretory System






20-22
Antennal or maxillary glands
Called green glands in decapods
End sac of antennal gland has a small vesicle and
a spongy labyrinth
Labyrinth connects by an excretory tubule to
dorsal bladder that opens to exterior pore
Hydrostatic pressure within a hemocoel provides
a force for filtration of fluid into the end sac
Resorption of salts and amino acids occurs as the
filtrate passes the excretory tubule and bladder
 Mainly regulates the ionic and osmotic
composition of body fluids
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
20-23
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Subphylum Crustacea



20-24
Nitrogenous wastes excreted across thin areas of
cuticle in the gills
Freshwater crustaceans constantly threatened by
over-dilution with water
 Gills must actively absorb Na+ and ClMarine crustaceans have urine that is isosmotic
with blood
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Subphylum Crustacea

Nervous and Sensory Systems



More fused ganglia than in other arthropods
Pair of supra-esophageal ganglia connects to eyes
and two pairs of antennae
Neuron connectives join this brain to the
subesophageal ganglion





20-25
Supplies nerves to mouth, appendages, esophagus, and
antennal glands
Double ventral nerve cord has a pair of ganglia for
each somite to control appendages
Eyes and statocysts are largest sensory organs
Tactile hairs occur on the body, especially on
chelae, mouthparts and telson
Chemical sensing of taste and smell occurs in hairs
on antennae and mouth
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Subphylum Crustacea







20-26
Statocyst opens at base of first antenna in
crayfish
Statocyst lined with sensory hairs that detect
position of grains of sand
Compound eyes, made of many units called
ommatidia
Cornea focuses light down the columnar
ommatidium
Distal retinal, proximal retinal, and reflecting
pigment cells form a sleeve around each
ommatidium
Each ommatidium detects a restricted area of
objects, a mosaic, in bright light
In dim light, the distal and proximal pigments
separate and produce a continuous image
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
20-27
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Subphylum Crustacea

Reproduction, Life Cycles, and Endocrine
Function

20-28
Diversity of Reproduction
 Barnacles are monoecious but generally crossfertilize
 In some ostracods, males are scarce and
reproduction is by parthenogenesis
 Most crustaceans brood eggs in brood
chambers, in brood sacs attached to the
abdomen, or attached to abdominal
appendages
 Crayfishes develop directly without a larval
form
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Subphylum Crustacea
Most crustaceans have a larva unlike the adult
in form, and undergo metamorphosis
 The nauplius is a common larval form with
uniramous first antennae, and biramous
second antennae and mandibles that all aid in
swimming
 Appendages and somites are added in a
series of molts
 Metamorphosis of a barnacle proceeds from a
free-swimming nauplius to a larva with a
bivalve carapace and finally to a sessile adult
with plates

20-29
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
20-30
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Subphylum Crustacea

Ecdysis






20-31
Necessary for a crustacean to increase in size the
 Exoskeleton does not grow
Physiology of molting affects reproduction,
behavior, and many metabolic processes
Underlying epidermis secretes cuticle
Outermost epicuticle is made of a very thin lipidimpregnated protein
Most of the cuticle is composed of several layers
of the procuticle
Exocuticle, beneath the epicuticle, contains
protein, calcium salts, and chitin
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
20-32
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Subphylum Crustacea





20-33
Endocuticle has a heavily calcified principal layer
and an uncalcified membranous layer
Molting animals grow in the intermolt phases, or
instars
Soft tissue increases in size until there is no
space within the cuticle
When body fills the cuticle, animal is in the
premolt phase
Epidermal cells enlarge before ecdysis
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Subphylum Crustacea





20-34
Secrete a new epicuticle and then begin secreting
a new exocuticle
Enzymes released into the area above new
epicuticle dissolve the old endocuticle
When only the old exocuticle and epicuticle
remain, the animal swallows water to expand and
burst the old cuticle
Soft new cuticle stretches and then hardens with
the deposition of inorganic salts
Molting occurs often in young animals and may
cease in adults
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
20-35
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Subphylum Crustacea

Hormonal Control of Ecdysis



20-36
Temperature, day length, or other stimuli trigger
central nervous system to begin ecdysis
Central nervous system decreases production of
molt-inhibiting hormone by the X-organ
Promotes release of molting hormone from the
Y-organs which promotes ecdysis
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Subphylum Crustacea

Other Endocrine Functions




20-37
Removing eyestalks accelerates molting and
prevents color changes to match background
Hormones from neurosecretory cells in eyestalk
control dispersal of cell pigment
Neurosecretions from pericardial organs
stimulate increase in heartbeat
Androgenic glands in male amphipods stimulate
expression of male characteristics
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Subphylum Crustacea

Feeding Habits





Same fundamental mouthparts are adapted to a
wide array of feeding habits
Suspension feeders generate water currents in
order to feed on plankton, detritus ,and bacteria
Predators consume larvae, worms, crustaceans,
snails, and fishes
Scavengers eat dead animal and plant matter
Crayfishes have a two-part stomach

20-38
Gastric mill grinds up food in 1st compartment
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
20-39
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Brief Survey of Crustaceans
Class Remipedia






Only 10 described species
All found in caves connected to the sea
Primitive features include 25–38 segments
with similar, paired, biramous, swimming
appendages
Antennules also biramous
Maxillae and maxillipeds are prehensile and
specialized for feeding
Swimming legs are directed laterally rather
than ventrally as is found in copepods and
cephalocarids
20-40
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
20-41
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Brief Survey of Crustaceans
Class Cephalocarida





Only 9 species described
Live in coastal bottom sediments from
intertidal zones to 300 meters depth
Thoracic limbs and 2nd maxillae are very
similar
Lack eyes, a carapace, and abdominal
appendages
True hermaphrodites and unique in
discharging eggs and sperm through same
duct
20-42
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Brief Survey of Crustaceans
Class Branchiopoda

Over 10,000 species, 4 orders
 Order Anostraca, includes fairy shrimp and
brine shrimp


Order Notostraca, includes tadpole shrimp


Enclosed by a bivalved carapace
Order Cladocera, includes water fleas

20-43
Carapace forms a large dorsal shield
Order Conchostraca, includes clam shrimp


Lack a carapace
Carapace encloses the body but not the head
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
20-44
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Brief Survey of Crustaceans




In all flattened, leaf-like legs serve as
respiratory organs, assist in suspension
feeding, and, (except for cladocerans),
locomotion
Most are freshwater
Important component of freshwater
zooplankton
May reproduce by parthenogenesis to rapidly
boost summer populations and then by
sexual reproduction with the onset of
unfavorable conditions
20-45
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Brief Survey of Crustaceans

Fertilized eggs highly resistant to cold



Critical for winter survival of population
Cladocerans: Development mostly direct
Other branchiopods: Gradual
metamorphosis
20-46
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Brief Survey of Crustaceans
Class Ostracoda





6,000 known species
Most are dioecious
Enclosed in a bivalve carapace
0.25–8.0 mm long
Fusion of trunk somites




Thoracic appendages are reduced to two or one
Most are benthic or climb onto plants, but
some are planktonic, parasitic, or burrowing
Widespread in both marine and freshwater
habitats
Development by gradual metamorphosis
20-47
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
20-48
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Brief Survey of Crustaceans
Class Maxillopoda

General body plan



Five cephalic, six thoracic and four abdominal
somites plus a telson
No appendages on abdomen
When present, the eye is unique in structure
and called a maxillopodan eye
20-49
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Brief Survey of Crustaceans
Subclass Mystacocarida




Less than 0.5 mm long
Live in interstitial water between sand grains
10 species have been described from around
the world
Primitive in several characteristics
20-50
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Brief Survey of Crustaceans
Subclass Copepoda





Third in numbers of species
Lack a carapace and retain simple, median,
nauplius eye in the adult
Single pair of uniramous maxillipeds and four
pairs of flattened, biramous, thoracic
swimming appendages
A major articulation separates the posterior
from the anterior, appendage-bearing portion
of the body
Antennules often longer than other
appendages
20-51
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Brief Survey of Crustaceans

Parasitic forms highly modified and reduced





Often unrecognizable as arthropods
Free-living copepods may be the dominant
consumer
Marine copepod Calanus is most abundant
organism in zooplankton by biomass
Cyclops and Diaptomus important elements
of freshwater plankton
Some free-living copepods are intermediate
hosts of human parasitic tapeworms and
nematodes
20-52
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Brief Survey of Crustaceans


Development is indirect
Some highly modified parasites have
unusual metamorphoses
20-53
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Brief Survey of Crustaceans
Subclass Tantulocarida







Only recently described
Approximately 12 species
Tiny copepod-like ectoparasites of deep-sea
benthic crustaceans
No head appendages beyond one pair of
antennae in sexual females
Likely alternate between a parthenogenetic
cycle and a bisexual cycle with fertilization
Tantalus larvae penetrate cuticle of host by
mouth tube
Abdomen and all thoracic limbs are lost
during metamorphosis to an adult
20-54
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
20-55
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Brief Survey of Crustaceans
Subclass Branchiura






Lack gills
Most are ectoparasites of marine and
freshwater fish
5–10 mm long
Broad, shield-like carapace, compound eyes,
four biramous thoracic swimming
appendages, and a short unsegmented
abdomen
Second maxillae are modified as suction cups
to attach to host fish
Development is direct
20-56
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
20-57
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Brief Survey of Crustaceans
Subclass Pentastomida






Tongue worms
Consist of about 90 species of parasites of
vertebrate respiratory systems
Most infect reptile lungs, a few infect air sacs
of birds or mammals
More common in tropical regions extending
out to North America, Europe, and Australia
Range from 1 to 13 cm in length
Chitinous cuticle regularly molted
20-58
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
20-59
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Brief Survey of Crustaceans

Five protuberances on the anterior end
provide the phylum name






Four of the protuberances bear claws
Fifth contains the mouth and two pairs of hooks
Simple straight digestive system
Nervous system has paired ganglia along the
ventral nerve cord
Lack any circulatory, excretory, or
respiratory organs
Sexes are separate
20-60
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Brief Survey of Crustaceans

Females larger than males




Larvae hatch out as oval, tailed creatures with
four stumpy legs
Most life cycles require an intermediate
vertebrate host, usually a fish or reptile
After ingestion by an intermediate host



Produces millions of eggs that pass up the host
trachea, are swallowed and leave host with feces
Larva penetrates intestine and migrates until it
changes to a nymph
Nymph becomes encapsulated and remains
dormant until eaten
When eaten, juvenile migrates to lung, feeds
on blood and tissue, and matures
20-61
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
20-62
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Brief Survey of Crustaceans
Subclass Cirripedia






Includes barnacles in order Thoracica and
three orders of burrowing or parasitic forms
Adults are sessile and attach directly (acorn
barnacles) or by a stalk (goose barnacles)
Carapace surrounds body and secretes a set
of calcareous plates
Head is reduced, abdomen is absent, and
thoracic legs are long with hairlike setae
Jointed cirri bear setae and extend from the
plates to feed on small particles
In barnacles in intertidal zones, plates close
to protect against dessication
20-63
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
20-64
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Brief Survey of Crustaceans

Most non-parasitic barnacles are
hermaphroditic and undergo metamorphosis
during development




20-65
Most hatch as nauplii and become cyprid larvae
with a bivalve carapace and compound eyes
Attach to substrate by first antennae and
adhesive glands
Secrete calcareous plates, lose eyes, and
transformation of swimming appendages to
filtering cirri
Parasitic forms may have a kentrogon stage that
injects cells into the hemocoel of host
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
20-66
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Brief Survey of Crustaceans
Class Malacostraca


Largest and most diverse class of Crustacea
with over 20,000 species
Contains three subclasses, 14 orders, and
many suborders
Order Isopoda



Only truly terrestrial crustaceans
Also have marine and freshwater forms
Dorsoventrally flattened, lack a carapace,
and have sessile compound eyes
20-67
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Brief Survey of Crustaceans







1st pair of thoracic limbs are maxillipeds
Remaining thoracic limbs lack exopods
Abdominal appendages bear gills, except for uropods
Common land forms include sow bugs and pill bugs
Cuticle lacks protection of insect cuticle
 Must live in moist habitats
Some isopods are highly modified as parasites of
fishes or crustaceans
Development typically direct but may be metamorphic
in parasitic forms
20-68
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
20-69
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
20-70
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Brief Survey of Crustaceans
Order Amphipoda

Amphipods resemble isopods





Lack a carapace, have sessile compound eyes,
and one pair of maxillipeds
However, they are compressed laterally, and
gills are in the thoracic region
Abdominal and thoracic limbs are grouped
for jumping and swimming
Many are marine, others are beach-dwelling,
freshwater, or parasitic
Development is direct
20-71
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
20-72
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
20-73
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Brief Survey of Crustaceans
Order Euphausiacea








Approximately 90 species
Includes important ocean plankton called krill
Carapace does not completely enclose gills
Lack maxillipeds and all limbs have exopods
Most are bioluminescent with a lightproducing organ called a photophore
Form a major component of the diet of baleen
whales and of many fishes
Eggs hatch as nauplii
Development is direct
20-74
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
20-75
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Brief Survey of Crustaceans
Order Decapoda






5 pairs of walking legs and 3 pairs of maxillipeds
In crabs, first pair of walking legs form pincers
Range from a few millimeters to the Japanese
crab with a 4 m leg-span
Approximately 18,000 species
Includes crayfishes, lobsters, crabs, and true
shrimp
Crabs have a broader cephalothorax and
reduced abdomen, compared to crayfish or
lobsters
20-76
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
20-77
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
20-78
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Phylogeny and Adaptive Diversification
Phylogeny





Remipedia appear to be the most primitive of
Crustacea
Fossils of an arthropod in the Mississippian
are likely the sister group to remipedians
One theory is that each modern somite
represents two ancestral somites that fused
together, forming the biramous appendage
The pentastomids were placed in Ecdysozoa
because of the similarities in larvae, molting of
the cuticle, and sperm morphology
Phylogenies based on rRNA genes and
affirmed in sequences of mitochondrial DNA
indicate that pentastomids are crustaceans
20-79
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Phylogeny and Adaptive Diversification
Adaptive Diversification




Crustaceans are unquestionably the
dominant arthropod in marine environments
They also share dominance in freshwater
environments with the insects
The class Malacostraca is most diverse and
members of Copepoda are most abundant
Copepods are particularly successful as
parasites of both vertebrates and
invertebrates
20-80
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Phylogeny and Adaptive Diversification
Classification



Class Remipedia
Class Cephalocarida
Class Branchiopoda
 Order Anostraca
 Order Notostraca
 Order Cladocera
 Order Conchostraca
20-81
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Phylogeny and Adaptive Diversification

Class Ostracoda
 Subclass Maxillopoda
 Subclass Mystacocarida
 Subclass Copepoda
 Subclass Tantulocarida
 Subclass Branchiura
 Subclass Pentastomida
 Subclass Cirripedia
20-82
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Phylogeny and Adaptive Diversification

Class Malacostraca
 Order Isopoda
 Order Amphipoda
 Order Euphausiacea
 Order Decapoda
20-83