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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
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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