Title: SP. Crustacea
1SP. Crustacea
- Circulatory system
- all arthropods have open circulatory system
- no veins separate blood from interstitial fluid
- annelids/vertebrates have closed system
- hemolymph leaves ? by arteries
- washes through hemocoel
- returns to ? via surrounding sinuses
- valves in arteries prevent backflow of hemolymph
- dorsal ? is propulsive organ
- single-chambered sac of striated muscle
- hemolymph colorless/reddish/bluish
- ameboid cells secrete thrombinlike coagulant to
prevent clotting - hemocyanin/hemoglobin are R pigments
2SP. Crustacea
- Nervous/sensory systems
- more fusion of ganglia than other arthropods
- more-developed sense organs than annelids
- supraesophageal ganglia supply nerves to
eyes/antennae - subesophageal ganglia supply nerves to
mouth/appendgages/ esophagus - double ventral nerve cord w/ pair of ganglia for
each somite controls appendages - tactile hairs on chelae/mouthparts/telson
- taste/smell via hairs on antennae/mouth
- statocyst lined w/ sensory hairs
- detect position of grains of sand (statholith)
- cmpd eyes made of ommatidia
- transparent area of cuticle (cornea)
- distal retinal/proximal retinal/reflecting
pigment cells form sleeve around each ommatidium - each ommatidium behaves as tiny eye
- restricted area of vision in bright light
3SP. Crustacea
- Reproduction and life cycle
- dioecious mostly
- most brood eggs in brood chambers/
brood sacs attached to
abdomen/
carry eggs w/ abdominal appendages - most crustaceans undergo metamorphosis
- nauplius is common larval form
- 3 pair appendages
- uniramous 1st antennae
- biramous 2nd antennae
- appendages/somites added
in series
of molts - ? are scarce in some ostracods
- reproduction via parthenogenesis
4SP. Crustacea
- Molting/ecdysis
- necessary to ? size
- affects reproduction/behavior/metabolic processes
- underlying epidermis secretes cuticle
- outermost epicuticle very thin lipid-impregnated
protein - most cuticle consists of 1 layers procuticle
- exocuticle beneath epicuticle
contains
protein/calcium salts/chitin - endocuticle
- heavily calcified principal layer
- uncalcified membranous layer
5SP. Crustacea
- epidermal cells enlarge before ecdysis
- secrete new epicuticle/exocuticle
- enzymes dissolve old endocuticle
- when only old exocuticle/epicuticle remain,
animal
swallows water to burst old cuticle - old exocuticle/epicuticle shed
- endocuticle secreted
- soft new cuticle stretches/hardens w/
deposition of
inorganic salts
6SP. Crustacea
- Hormonal control of ecdysis
- temperature/day length/other stimuli trigger CNS
to begin ecdysis - CNS ? production of molt-inhibiting hormone by
X-organ - promotes release of molting hormone from Y-organs
- triggers ecdysis
- Other endocrine func.
- removing eyestalks accelerates
molting (b/c remove
X-organ) - prevents camouflage color changes
- hormones from neurosecretory
cells in
eyestalk control pigment
dispersal
7SP. Crustacea
- Feeding habits
- same fundamental mouthparts adapted to wide array
of feeding habits - suspension feeders generate water currents to eat
plankton/detritus/bacteria - predators consume larvae/worms/crustaceans/snails/
fishes - scavengers eat dead animal/plant matter
8SEE TABLE on p. 402
9SP. Crustacea C. Remipedia
- 10 described sp.
- Live in caves connected to sea
- 25-38 segments w/ similar/paired/
biramous/swimming appendages - Biramous antennules
- Prehensile maxillae/maxillipeds
specialized for feeding - Swimming legs directed laterally
- ventrally in copepods/cephalocarids
- Most primitive crustacean?
10SP. Crustacea C. Cephalocarida
- 9 described sp.
- Live in coastal bottom sediments
- intertidal to 300 m
- Thoracic limbs/2nd maxillae very similar
- Lack eyes/carapace/abdominal appendages
- True hermaphrodites
- discharge eggs/sperm via same duct
11SP. Crustacea C. Branchiopoda
- 10,000 sp. in 4 O.
- O. Anostraca includes fairy shrimp/brine shrimp
- lack a carapace
- O. Notostraca includes tadpole shrimp
- carapace forms large dorsal shield
- O. Conchostraca includes clam shrimp
- bivalved carapace
- O. Cladocera includes water fleas
- carapace encloses body not head
12SP. Crustacea C. Branchiopoda
- All have flattened/leaf-like legs
- 1 R organs
- suspension feeding/locomotion
- Most freshwater zooplankton
- Parthenogenic
- rapidly boost summer populations
- then sexual reproduction w/ onset of unfavorable
cond. - Fertilized eggs resistant to cold
- critical for winter survival
- Direct development/gradual metamorphosis
13SP. Crustacea C. Ostracoda
- 6,000 known sp.
- Most dioecious
- Bivalve carapace
- resemble tiny clams
- 0.25 - 8.0 mm
- Marine/freshwater
- Considerable fusion of trunk somites
- thoracic appendages reduced to 1-2
- gradual metamorphosis
14SP. Crustacea C. Maxillopoda
- General body plan
- 5 cephalic, 6 thoracic, 4 abdominal somites
telson - no appendages on abdomen
- SubC. Mystacocarida
- lt0.5 mm
- live in interstitial water btwn sand grains
- 10 described sp.
15SP. Crustacea C. Maxillopoda
- SubC. Copepoda
- 3rd in sp.
- lack carapace
- retain nauplius eye in adult
- 1 pair of uniramous maxillipeds
- 4 pairs of flattened/biramous/thoracic
swimming appendages - major joint separates posterior from anterior
- appendages on anterior
- antennules often longer than other appendages
- parasites of both vertebrates and invertebrates
- Calanus is most abundant organism in marine
zooplankton by biomass - Cyclops/Diaptomus impt freshwater plankton
- intermediate hosts of human parasitic
tapeworms/nematodes
16SP. Crustacea C. Maxillopoda
- SubC. Tantulocarida
- 12 describe sp.
- tiny copepod-like ectoparasites of deep-sea
benthic crustaceans - larvae penetrate cuticle of the host by a mouth
tube. - no head appendages beyond 1 pair of antennae in
sexual ? - likely alternate btwn parthenogenetic
cycle/bisexual cycle w/ fertilization - abdomen/all thoracic limbs lost during
metamorphosis to adult
17SP. Crustacea C. Maxillopoda
- SubC. Branchiura
- lack gills
- parasites of marine/freshwater fish
- 5-10 mm
- broad carapace
- compound eyes
- 4 biramous thoracic swimming appendages
- short unsegmented abdomen
- 2nd maxillae modified as suction cups
- hold on to host fish
- direct development w/o nauplius stage
18SP. Crustacea C. Maxillopoda
- SubC. Cirripedia (barnacles)
- barnacle adults sessile
- attach directly or by stalk
- acorn vs. goose barnacles
- carapace surrounds body
- secretes set of calcareous plates
- head reduced, abdomen absent
- long thoracic legs w/ hairlike setae
- many-jointed cirri bear setae
- feed on small particles
- intertidal barnacles exposed to drying
- plates close to protect them
19SP. Crustacea C. Maxillopoda
- monoecious/hermaphroditic
- metamorphosis
- hatch as free-swimming nauplii
- become cyprid larvae w/ bivalve carapace
compound eyes - attach to substrate by 1st antennae/adhesive
glands - secrete calcareous plates/lose eyes/change
swimming appendages to filtering cirri
20SP. Crustacea C. Malacostraca
- 20,000 sp
- most diverse
- largest C. of Crustacea (14 O.)
- O. Isopoda
- terrestrial (sow bugs/pill bugs)
- also marine/freshwater
- dorsoventrally flattened
- lack carapace, sessile compound eyes
- 1st pair of thoracic limbs are maxillipeds
- remaining thoracic limbs lack exopods
- abdominal appendages bear gills
- must live in moist conditions b/c
cuticle lacks protection of insect cuticle - some parasites of fish/crustaceans
- usually direct development
21SP. Crustacea C. Malacostraca
- O. Amphipoda
- resemble isopods
- lack carapace, sessile compound eyes
- 1 pair of maxillipeds.
- compressed laterally
- gills in thoracic position
- abdominal/thoracic limbs grouped
for
jumping/swimming - marine/freshwater/parasitic
- direct development
22SP. Crustacea C. Malacostraca
- O. Euphausiacea (krill)
- 90 sp.
- carapace does not completely enclose gills
- lack maxillipeds and have all limbs equipped
w/ exopods - most are bioluminescent via photophore
- major component baleen
whale/fish diet
23SP. Crustacea C. Malacostraca
- O. Decapoda (crayfishes/lobsters/crabs/true
shrimp) - 18,000 sp.
- 5 pairs of walking legs
- 3 pairs of maxillipeds
- 1st pair of walking legs form pincers
- few mm ? largest arthropod (Japanese crab)
- crabs have broad cephalothorax/reduced abdomen