ZOO 115 Invertebrate Zoology

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ZOO 115 Invertebrate Zoology

• Subphylum Crustacea

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Arthropoda Subphylum Crustacea

• 42,000 species
• Major trophic link between primary producers
  (phytoplankton) and higher level consumers
• Mostly aquatic
• Three part brain
• Two pair of antennae
• Tactile
• Chemosensory
• Many legs
• Mostly separate sexes

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Subphylum Crustacea
Shrimps and shrimp-like animals
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Subphylum Crustacea
Lobsters and crawfish
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Subphylum Crustacea
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Class Branchiopoda Order Anostraca

• Can tolerate desiccation and high salinity
• 15-30 mm in length
• Elongate shrimp-like bodies without a carapace
• Have stalked compound eyes
• Most are suspension feeders
• Swim ventral side up
• Use their thoracic appendages for capturing food
  particles
• Food is passed to a central groove, encased in
  mucus and moved forward to mouth.
• Gonochoric
• Nauplius larvae

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Class BranchiopodaOrder Notostraca

• Tadpole shrimps
• None occur in oceans
• Feed on organic matter in sediments some are
  predators or scavengers
• Characteristic broad shield-like carapace and
  long caudal rami
• Triops considered a major pest in rice fields

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Class BranchiopodaOrder Diplostraca

• Clam shrimps and cladocerans
• Mostly freshwater
• Scavengers, predators, detritivores, and
  suspension feeders
• Well developed clam-like carapace
• All have a dorsal organ that could function as
• Salt gland
• Neck Gland
• Adhesion
• Swim with their powerful second antenna

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Class BranchiopodaOrder Diplostraca

• Sexes
• Hermaphroditism
• Gonochorism
• Type of reproduction
• Monosexual -Parthenogenesis
• Bisexual reproduction - normal sexual
  reproduction
• Eggs
• Summer - thin-shelled
• Winter - resting

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Cladoceran reproductive strategies
Stable conditions
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Cladoceran reproductive strategies
Unstable conditions
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Subphylum CrustaceaClass Malacostraca

• Number of segments

• Appendages
• Head - sensory and feeding
• Thoracic - crawling or grasping
• Abdominal (unique to this Class and Remipedia) -
  swimming and copulation

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Class MalacostracaOrder Stomatopoda

• Mantis shrimps
• Specialized predators
• No cephalothorax
• Head, thorax and abdomen
• Two large stalked compound eyes and a third
  medial naupliar eye

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Class MalacostracaOrder Stomatopoda

• Triramous antennae

• Has abdominal gills like isopods
• Enormous digestive cecum
• Very well developed heart and hemal system

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Class Malacostraca Order Euphausiacea

• Krill
• All pelagic
• Major source of food for whales, squids and
  fishes
• Thoracic gills external to carapace

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Class MalacostracaOrder Decapoda

• Shrimp-like
• IO Caridea (shrimp)
• SO Dendrobranciata SF Penaeoidae (prawns)
• IO Stenopodidea

• Lobster-like
• IO Astacidea (lobster)
• IO Palinura (spiny and slippery lobster)
• IO Thalassinidea (ghost shrimp)

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• Crab-like
• IO Brachyura (True crabs)
• IO Anomura

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Class MalacostracaOrder Decapoda

• Feeding
• 6 pair of feeding appendages
• 1 pr Mandibles
• 2 pr Maxillae
• 3 pr Maxillipeds
• Most predators and/or scavengers, some suspension
  feeders, some detritivores, some herbivores, some
  onmivores

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Class MalacostracaOrder Decapoda

• Internal anatomy

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Class MalacostracaOrder Decapoda

• Sense organs
• Legs
• Antennae
• 1st
• Stalked compound eye

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Class MalacostracaOrder Decapoda

• Chromatophores
• Shrimps especially good at changing color

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Class MalacostracaOrder Decapoda

• Reproduction
• Most separate sexes (gonochoric)
• Sperm transfer indirect (spermatophores)
• Many have copulation
• Bachyurans may block fertilization for up to a
  year following copulation

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Class MalacostracaOrder Decapoda

• Lobster
• Life cycle

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Class MalacostracaOrder Decapoda

• Crab
• Life cycle

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Class Malacostraca Order Mysida

• Mysid shrimps
• Most 2-30 mm
• Gnathophausia - 35 cm
• Omnivorous suspension feeders
• Well developed carapace and tail fan

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Class Malacostraca Order Isopoda

• Isopods, pill bugs
• 10,000 sp
• 0.5 50 cm
• Virtually all habitats
• Flattened dorso-ventrally

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Class Malacostraca Order Amphipoda

• Amphipods
• 8000 sp.
• 1mm-25 cm
• In almost every habitat
• Flattened laterally
• Carapace absent
• Gills thoracic