Lab 10: Phlyum Arthropoda, Subphylum Crustacea
4 November 1999
Subphylum Crustacea
(= a crust) A predominantly aquatic group with most species occurring in marine environments. Head appendages include 2 pair of antennae, mandibles, and 2 pair of maxillae. Thoracic appendages include 3 pair of maxillipeds and 5 pair of pereopods (walking legs). Abdominal appendages include 5 pair of pleopods (swimmerets) and 1 pair of uropods. Appendages are typically biramous. Most species have a carapace that covers all or some of the body.Class Maxillopoda
Subclass Ostracoda: Small marine benthic animals with a body enclosed in a bivalved carapace that resembles a bivalve shell.
Subclass Copepoda: Abundant group of planktonic animal (mostly marine), members of which are herbivorous, carnivorous, omnivorous, or parasitic. Herbivorous marine copepods feed on phytoplankton and are an important part of the oceanic food chain: they are the primary food source for marine carnivores. Copepods lack gills and abdominal appendages. Most species have a single median eye (rather than a pair of compound eyes).
Subclass Cirrepedia: barnacles. This is the only group of sessile crustaceans.
Class Branchiopoda:
Subclass Cladocera: water fleas
Subclass Anostraca: fairy shrimp
Class Malacostraca: Most crustaceans are malacostracans (75%). Malacostracans exhibit the typical crustacean body plan: head (5+1 segments, 5 pairs of appendages), thorax (8 segments, 8 pairs of appendages), abdomen (6+1 segments, 6 pairs of appendages).
Order Stomatopoda: mantis shrimp. Mantis shrimp have the most highly developed crustacean eye, and use sound (shock) waves to stun prey.
Order Euphausiacea: krill.
Order Isopoda: Dorso-ventrally flattened animals. Typically benthic, marine animals, but includes sowbugs (a terrestrial group).
Order Amphipoda: scuds, sand fleas. Laterally compressed animals.
Order Decapoda: (all the edible ones) crabs, lobsters, shrimp, crayfish. All have large, stalked compound eyes.
Examine a specimen of Callinectes sapidus (blue crab) or Carcinus maenus (green crab). Follow procedure outlined in W&T (pp. 219-222).
EXTERNAL ANATOMY: identify carapace, abdomen, eye, antennae, antennules, 1st maxilla, 2nd maxilla, mouth, mandibles, 1st maxilliped, 2nd maxilliped, 3rd maxilliped, walking legs (all 5), pleopods, chela, paddle (if Callinectes)
Be sure you can tell male from female crabs from external anatomy alone.
Examine carefully the crayfish appendages on demonstration. Be able to tell these appendages apart. Refer to W&T pp.214-217.
Know the difference between exopods (exopodites) and endopods (endopodites), exites (epipodites) and endites. (In a general sense, NOT specifically for each appendage.)
REMEMBER the articles of an endopod: coxopodite, basiopodite, ischiopodite, meropodite, carpopodite, propodite, dactylopodite
(Can Bad Indigestion Make Crayfish Pentient Drinkers)
-or-
(Charles Bronson Is Mighty Cool, Perhaps Dudely)
Systematic Classification
Phylum Arthropoda
Subphylum Trilobitomorpha
- trilobitesSubphylum Cheliceriformes
- scorpions, sea spiders, spiders,
Subphylum Uniramia
- insects and myriapodsSubphylum Crustacea
- aquatic, mostly marineClass Remipedia - remipedes, one species in a Bahamian cave
Class Cephalocardia - Cephalocarids, primitive (e.g. Hutchinsoniella)
Class Branchipoda
- fair shrimps, brine shrimps, tadpole shrimps, cladocerans, clam shrimps, etc.Order Anostraca - fairy and brine shrimps
Artemia
Branchipus
Order Notostraca - tadpole shrimps
Triops
Order Cladocera - water fleas
Daphnia
Order Conchostraca - clam shrimps, laterally compressed, bivalve
Cypris
Class Maxillopoda
- large maxillae for feeding, usually 11 segments in trunkSubclass Ostracoda - mussel or seed shrimps, bivalve carapace
Subclass Mystacocarida - mysticocarids, 5 segments on thorax and abdomen, each
Subclass Branchiura - fish lice (argulids)
Argulus
Subclass Copepoda - copepods (3 main orders)
Order Calanoida - tapering
Order Harpacticoida - bulbous front end
Order Cyclopoida - cigar shaped
Cyclops sp.
Subclass Cirripedia - barnacles, etc.
Balanus balanoides
Lepas
Slijper - parasitic
Subclass Tantulocarida - tantulocarids
Class Malacostraca
- higher crustaceans, thorax usually 8 segments*
Names in boxes indicate important conceptual groups of the Malacostracans.Subclass Phyllocarida - Phyllocarid shrimps, primitive, unhinged bivalve, rare
Subclass Eumalacostraca
(Superorder Hoplocarida)
Order Stomatopoda - mantis shrimp, flattened,
Squilla
Pseudosquilla
(Superorder Eurcarida)
Order Euphausiacea - euphausiid shrimp, krill
Order Decapoda – crabs, shrimps, lobsters
(Peneid Shrimps, e.g.) Penaeus sp. – brown shrimp
Infraorder Caridea – caridean shrimps
Crangon vulgaris – mud shrimp
Crangon septemspinosus – seven spine bay shrimp
Palaemonetes sp. – grass shrimp
Palaemonetes pugio – grass shrimp
Infraorder Astacidea – crayfish and chelate lobsters
Cambarus sp. – freshwater crayfish
Homarus americanus – northern lobster
Infraorder Palinura – spiny and Spanish lobsters
Infraorder Anomura – hermit crabs, sand crabs, etc.
Pagarus sp. – hermit crab
Pagarus calliotus – hermit crab (from Naples)
Eupagurus pollicans – hermit crab
Emerita talpoida – Atlantic coast mole crab
Hippa sp. – Pacific mole crab
Infraorder Brachyura – true crabs, big chela, abdomen folded under
Libinia emarginata – spider crab
Cancer irroratus – rock crab
Carcinus maenus – green crab
Callinectes sapidus – blue crab (Family Portunidae, swimmers)
Planes minutus – Gulf or Sargassum crab
Uca sp. – fiddler crab
Uca minax – redjointed fiddler crab
Uca pugnax – Atlantic marsh fiddler crab
Uca pugilator – Atlantic sand fiddler crab
Gelasimus sp. – fiddler crab
Ocypode albicans – ghost crab
Libinia sp. – spider crab
Libinia dubia - longnose spider crab
Libinia emarginata – common or portly spider crab
(Superorder Peracarida - no extensive carapace)
Order Mysida
Order Cumacea
Order Tanaidacea
Order Isopoda - dorsoventrally flattened , pill bugs, rock lice, etc.
Porcelanid isopod specimen
Order Amphipoda - laterally flat. , beach hoppers, sand fleas, scuds
Cyanthura polita - marine
Sand fleas
Gammarus sp.
Jassa sp.
