LECTURE 13 - Ecdysozoa: Crustacea Flashcards
1
Q
(IN PANCRUSTACEA - IN OLIGOSTRACA) What are Mystacocarida?
A
- Minute interstitial crustaceans living in the meiobenthos: about 20 species
- Anatomy by segment (TOP TO BOTTOM)
- Antennule
- Antenna
- Head: 2 mandibles, 2 maxillae, 2 maxillipeds
- 4 thoracic appendages
2
Q
(IN PANCRUSTEA - IN OLIGOSTRACA) What are Branchiura?
A
- Fish lice: ectoparasites of fish: about 130 species
- Anatomy
- Compound eyes
- Poison spine
- Proboscis
- Maxilla with sucker for attachment
- Maxilliped
- Carapace-like lobes on the sides of the head
- 4 pairs of thoracic limbs
- Abdomen highly reduced
3
Q
(IN PANCRUSTECEA - IN OLIGOSTRACA) What are Pentastomida?
A
- Tongue worms: obligate parasites of the respiratory tract of vertebrates - about 120 species
- Phylogenetic position long uncertain
- Now known to be ecdysozoans, with some morphological and molecular similarities to crustaceans
4
Q
(IN PANCRUSTACEA - IN OLIGOSTRACA) What are Ostracoda?
A
- Ostracods: small freeliving bivalved crustaceans: about 10,000 species, plus 50,000 extinct species
- Extremely abundant and diverse in freshwater and marine habitats
- Head appendages greatly developed and used for feeding
- Trunk appendages reduced
- Feeds on algae and other small organisms
- Large items pulled into shell by antennae or mandibles
- Smaller items gathered by fans of setae on limbs
- Often parthenogenetic
5
Q
(IN PANCRUSTACEA - IN MULTICRUSTACEA) What are Malacostraca?
A
- Crabs, lobsters, shrimps, scuds, krill, woodlice: about 25,000 species
6
Q
(IN PANCRUSTACEA - IN MALACOSTRACA) What are Leptostraca?
A
- Sister group to Eumalacostraca
- Benthic marine crustaceans in all oceans
- Filter-feeders and scavengers
- Small (5-15 mm)
- Large carapace with two valves that covers head and thorax
- Pleopods with gills on abdominal segments
- Fossils from late Cambrian
7
Q
(IN PANCRUSTACEA - IN MALACOSTRACA) What are Decapods?
A
- Krill, mantis shrimp, shrimps and prawns (non-brooders), shrimps (brooders), spiny lobsters and slipper lobsters, crayfish and lobsters, hermit crabs, crabs
8
Q
(IN PANCRUSTACEA - IN MALACOSTRACA) What are Mysida?
A
- Mysids are common marine crustaceans; a few species are glacial relicts in the Great Lakes and other deep, cold, oligotrophic northern lakes
- 6 pairs of thoracic swimming limbs, covered by carapace; 6 pairs of swimmerets on abdomen
- Female brooders eggs in pouch made from plates projecting from base of thoracic limbs
- Mysis feeds mostly on zooplankton in the deeper waters of lakes below the thermocline
- It is itself an important component of the diet of fish
9
Q
(IN PANCRUSTACEA - IN MALACOSTRACA) What are Amphipoda?
A
- Scuds, beach-hoppers, freshwater shrimps
- Medium-sized (1-100 mm) animals, laterally flattened
- Freshwater and marine; about 10,000 species
- Mostly scavengers and detritivores
- Freeliving except the whale louse Cyamus
10
Q
What is the body plan of a Amphipod?
A
- No carapace; head thorax fused, with 2 antennae plus mouthparts
- Thorax: 8 segments bearing accessory mouthparts (1); uniramous limbs direct forward (3) and limbs directed backwards (4)
- Abdomen: swimming legs plus terminal appendages
11
Q
(IN PANCRUSTEACE - IN MALACOSTRACA) What are Isopoda?
A
- Woodlice, pill bugs, slaters
- Terrestral, freshwater and marine crustaceans
- By far, the most successful terrestrial crustacenas
- About 10,000 species
12
Q
What is the body plan of Isopods?
A
- Head with 2 pairs of antennae; mandibles; maxillae; maxillipeds
- Reduced carapace
- 7 thoracic segments with uniramous limbs
- 5 abdominal segments with biramous limbs (swimming and respiration)
- Abdominal limbs bear “lungs” in terrestrial isopods
13
Q
Give an example of a parasitic isopod.
A
- Cymothoa exigua (tongue-eating louse) is a parasitic isopod
- This parasite enters fish through the gills, and then attaches itself at the base of the fish’s tongue
- The female attaches to the tongue and the male attaches on the gill arches beneath and behind the female
- The parasite destroys the fish’s tongue, and then attaches itself to the stub of what was once its tongue and become the fish’s new tongue
14
Q
(IN PANCRUSTACEA - IN MULTICRUSTACEA) What are Maxillopoda?
A
- Copepoda: small zooplankton crustaceans of lakes and oceans - about 13,000 species
- Cirripedia: Barnacles, sessile marine crustaceans - about 1,200 species
15
Q
(IN PANCRUSTACEA - IN MAXILLOPODA) What are Copepoda?
A
- Extremely abundant in marine and freshwater habitats
- Planktonic and benthic forms
- Scavengers, herbivores and carnivores
- Many copepods are parasitic and often strongly modified
- About 15,000 species
