Arthropoda 3

7/27/2019 Arthropoda 3

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Wrestling with Crustacean TaxonomyI cant

remember what

class Im in

SubPhylum Crustacea

What do you Know about the SP:

Crustacea

5 head segments:

2 pr antennae

Mandibles

Maxillae

Segmented trunk with appendages

Nauplius larvae

Basic Crustacean Taxonomy Subphylum Crustacea (5 classes to recognize; 3 to know

well)

Class Remipedia

Class Cephalocarida

Class Branchiopoda Brine shrimp, tadpole shrimp

Class Maxillopoda barnacles, copepods, ostracods

Class Malacostraca Crabs, lobsters, shrimp, pill bugs, krill

Remipedia (only 12 species)

Cave Dwelling

Homonomous appendages on trunk

Only 12 individuals found

Class Cephalocarida (10 species)

Tiny (1-4 mm)

5-8-11 structure

Eyes are absent


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Class Branchiopoda (900 species)Include Tadpole Shrimp or Triops, Brine shrimp and Clam

shrimp

Mostly fresh water

Reduced tagmosis

Thoracic appendages are primitive, biramous and phyllopodous

Eggs can survive drying for centuries

Order Anastraca: Artemia: These all lack

a carapace

Order Notostraca: Triops/tadpole shrimp

Have a broad carapace like a shield

Order Diplostraca: Daphnia and clam

shrimp. These all have a bivalved

carapace

And some more triops pictures.

Class MaxillopodaIncludes some very diverse forms including barnacles,

copepods, and ostracods. Free living and parasitic

With six thoracic somites and four abdominal. Includes a

telson (5-6-4)

Over 25,000 species described but probably many times this to

be described

Class Maxillopoda

Subclass Thecostraca

Subclass Copepoda

Subclass Ostracoda

Subclass Tantulocarida

Subclass Branchiura

Subclass Pentastomida

Subclass Mystacocarida

Class Maxillopoda

Subclass Thecostraca

Barnacles

Subclass Copepoda

Copepods

Subclass Ostracoda

Ostracods

Class Maxillopoda:Subclass Thecostraca

Cirripedia

Collectively known as barnacles

Have a bivalved larval phase called a cypris larvae

Larva pelagic, adults sessile

Simultaneous hermaphrodites


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The familiar barnacles, acorn and gooseneck

Build a mollusk-like shell composed of calcium carbonate

Shell composed of many plates (tergum, scutum, rostrum,

carina)

Trend from primitive to advanced is reduction in number

of plates

Feed with modified thoracic appendages called Cirri

Balanomorpha Cirripedians are sessile and historically were considered Mollusks

Marine

Will attach to anything (look for settled barnacles in May and June)

Cypris larvae settle using cement glands (in the head)

From Costlow1957

Barnacle feeding

Lepas anatifera


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Some select barnacles: Reproduction and Development

Only sessile hermaphroditic crustacean

Cross fertilization is the norm and animals are usually

functionally male or female at a given time

Copulation is required for fertilization and spermatophores are

deposited near ovary. Penis is quite extensible

Nauplius develops into a cypris larva which when exposed to

proper cues will settle

Rhizocephalans are cirripedians

Internal parasites of other crustaceans

Only recognizable as cirripedes when in larval stage

Some forms have unique larval phase called a kentrogon

Can limit crab populations in some regions

Parasitism


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Class Maxillopoda

Subclass Copepoda

Includes pelagic, benthic, infaunal, and parasitic forms

Well developed cephalic shield

Incredible diversity; some speculate that copepods are the

most diverse of the crustaceans but as yet only fraction

described

Main free-living orders and parasitic orders

Some free-living copepods:

Harpacticoid

Cyclopoid

Calanoid

Important planktonic feeders

also quite important in the food chain

And some parasitic forms:Ostracods: seed shrimp

M

A

L

O

C

O

S

T

R

A

C

A

Class Malacostraca: Order Decapoda (having 10 legs)

3 pr maxillipeds

5 pr walking legs (periopods)

5 pr pleopods

1 pr uropods (contributes to tailfan)

May be benthic burrowing, or

pelagic.

Still have 14 trunk segments(5,8,6,)


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Subclass Phyllostraca

Subclass Eumalacostraca

Often abundant in organic rich environments

Very few species (36) extant. Diverse fossil

forms, among earliest recognizable crustaceans

A Phyllostracan

Subclass Eumalacostraca

5-8-6 somite arrangement

4 Superorders (3 to know)

1) Hoplocarida: Stomatopods 2ndthoracic appendage is modified for smashing/spearing

2) Syncarida:

3) Eucarida: euphausids, mysids, and decapods Having stalked compound eyes

4) Peracarida: cumaceans, isopods and amphipods(contain 30% of all crustaceans)

Presence of a marsupium

Stomatopoda (mantis shrimps)

Pound for pound probably the most vicious animals that have

ever lived (luckily they are usually less than 30 cm)

Eat almost any animal they encounter, try to kill whatever enters

their territory

Two types, smashers and spearers

STOMATOPOD BOXING

http://www.ucmp.berkeley.edu/aquarius/raps.html

RubiksCube

Superorder Peracarida

Order Mysidacea

Order Isopoda

Order Amphipoda

Order Cumacea

Order Tanaidacea

Order Lophogastrida

Order Mictacea

Order Thermosbaenacea

Superorder Peracarida

Order Mysidacea: mysids

Order Isopoda: isopods/pill bugs

Order Amphipoda: sand fleas, amphipods

Order Cumacea: cumaceans

Have a marsupium


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Orders Mysidacea

Abundant pelagic and epibenthic forms

Important local food source for fishes

Order

Isopoda

Dorso-ventrally

compressed

Order Isopoda Order AmphipodaLaterally compressed

Called beach hoppers or sand fleas

CumaceansAbundant infaunal crustaceans

Can be major food for whales

Have three pairs of maxillipeds


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Superorder Eucarida Euphasidae

Decapoda Dendrobranchiata

Pleocyemata

Caridea

Brachyura

Anomura

Astacidea

Pallinura

Thalassinidea

Eucarida:

having stalked eyes, complete carapace fused with thoracic

segments/cephalothorax

Order Euphausiacea

Form vast monotypic

schools, especially in

southern oceans

One school was

estimated to equal the

total weight of entire

world fishery all

species included

Unlike decapods have

external gills

Order Decapoda

First three thoracopods modified as maxillipeds

Thus, five pairs of pereiopods left for locomotion

Includes most commercially important crustaceans

Two distinct Suborders: (Some shrimp) and (Crabs, Lobsters

and some other shrimp)

Two distinct Suborders:

(Dendrobranchiata) and (Pleocymata)

Dendrobranchiata

Includes the Gulf and Tiger Prawns

Most important commercial shrimp

Not closely related to other decapods, even shrimp!

Do not brood embryos, retain nauplius larva

Suborder Pleocyemataall of these brood eggs on pleopods

all of these lack dendrobranchiate gills

Infraorder Palinura: slipper lobsters, spiny lobsters

Infraorder Astacidea: lobsters and crayfish

Infraorder Stenopodidea: cleaner shrimp

Infraorder Thalassinidea: mud or ghost shrimp

Infraorder Anomura: king crabs and hermit crabs

Infraorder Caridea: true shrimp

Infraorder Brachyura: true crabs


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True lobsters and crayfish

Chelae on first three pereiopods

Freshwater and marine

Exclusively tropical

Often cleaner shrimp

First three pereiopods chelate, P3 largest

Called mud shrimps or ghost shrimps

Commonly estuarine and Usually burrowingTrue shrimp

First two pereiopods chelate

94 species recorded from Alaska

Infraorder Anomura

asymmetrical tailed decapods

Typified by having fifth pereopod greatly reduced

Includes

hermit crabs

mole crabs

king crabs

Paguroidea- Family Paguridae

Other families:

Diogenidae

Coenobitidae


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Other Anomurans:

Patsy A. McLaughlin, Rafael Lemaitre, 1997

Patsy A. McLaughlin, Rafael Lemaitre, 1997

Infraorder Brachyura

Called true crabs to distinguish from the anomuran crabs

Very diverse, world-wide group

Infraorder Brachyura

Family Majidae

Spider crabs

THE CRUSTACEAN EYESTALK

X-ORGAN Sinus Gland

Growth Coloration Metabolism Reproduction

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Arthropoda 3