class anostraca fairy and brine shrimp 27 trunk segments; only anterior segments (thorax) with...
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Class Anostraca
• Fairy and brine shrimp• 27 trunk segments; only
anterior segments (thorax) with appendages (phyllopoda)
• Thorax and abdomen distinct only by presence of appendages
Class Branchiopoda
• Water fleas• Clear separation of tagmata
reduced; head and trunk• Mouth simple• Thoracic appendages adapted
for swimming; Abdomen lacks appendages
• Apparent segmentation lost• Body shape is different from
carapace
• Microscope slide of Daphnia
Class Malacostraca
• Large group of Crustacea (>20,000 species)
• See intro p.625 of lecture text for key features (Fig 19-19)
• General theme– 3 tagmata– Biramous, uniramous,
biramous
Order Stomatopoda
• Mantis shrimp• Depressed body• 3 tagmata• Shield-like carapace• Raptorial 1st pair thoracic
appendages• First antennae triramous• P. 627
Order Decapoda
• Largest order of Malacostraca
• Both antennae biramous
• 2 tagmata (cephalothorax and abdomen)
• Biramous, uniramous, biramous.
• Modification of first periopod in many
• Mouthparts 6, thoracic appendanges 5
• Divergence of mouthparts varies
Order Mysidacea
• Shrimp-like but not decapods because retain many primitive characteristics
• Head with 3 fused thoracic segments
• Carapace onlyy attached 1st – 3rd thoracic segments but looks like cephalothorax
• Tagmata not fused
O. Amphipoda
• Compressed body• No carapace• 3 tagmata• 1 – 2 thoracic segments fused
to head (8 thoracic segments)• Gnathopods are first two pair
thoracic appendages not fused to head
• 6 segments Ab split into two parts
O. Isopoda
• 3 tagmata• Head and 1st thoracic segment
fused• Depressed body• The 7 thoracic appendages
generally unspecialized (all look the same)
• Last Ab segment fused with telson (pleotelson)
• Remaining Ab segments (5) have biramous pleopods
• Biramous, uniramous, biramous
preserved specimens
Class Copepoda
• Body tapers anterior to posterior
• Short trunk (Th + Ab) 10 or fewer segments
• Head includes 3 fused thoracic segments
• Ab 4 segments, no appendage• Posterior extensions rami, not
uropods as in Malacostraca• 1st antennae variabe in size,
can be long• On slides
Class Cirripedia
Order
• d