1. ZOO 115 Invertebrate Zoology
Subphylum Crustacea
Part II

2. Class Maxillopoda Small crustaceans with a small trunk Subclasses
Branchiura
Ostracods
Barnacles
Copepods
Mystacocarida
Pentastomida
Tantulocarida
Thecostraca*
Copepoda*
Ostracoda*
Branchiura*

3. Subclass Thecostraca (Barnacles)
Most sessile
Acorn
Stalked (Gooseneck)
Some Parasitic

4. Subclass Theostraca - Anatomy
Sessile forms
Shell (calcareous plates) for preventing dessiciation and protection
Hermaphrodites
Penis 15X body length

5. Subclass Thecostraca Development Nauplius larvae Cypris larvae
Cypris larvae

6. Subclass Thecostraca Economic importance

7. Subclass Copepoda Number of species
2nd largest class in Arthropoda (Malocostraca 1st) with respect to number of species
Possibly numerically the most abundant metazoans on earth.
Size
Most small 1-5 mm
Some freeliving up to 17 mm
Parasitic up to 32 cm

8. Subclass Copepoda – General Anatomy
Simple Median Eye
Single median eye
Distinctive narrowing of body at abdomen
No abdominal appendages
Caudal Rami
Well developed caudal rami

9. Subclass Copepoda – Calanoid
Live primarily in plankton
both marine and freshwater
1st pair of uniramous Antennae for propulsion and flotation
In males used to hold female for copulation
2nd pair of biramous antennae for propulsion
Large oil sac in thorax for flotation and food reserves (often red or blue)

10. Subclass Copepoda – Calanoid
Suspension feeders
2nd pair of maxilla used for suspension feeding
From Ruppert, Fox and Barnes (2004)
Pareuchaeta norvegica (Foto: Hege Vestheim)
Few are predators
Few are omnivores
Eats juvenile fishes

11. Subclass Copepoda - Harpacticoid
Tigriopsis californicus
Most epibenthic
most detrivores
some predators
some planktonic forms
Also use large oil sac for flotation and food reserves (often red or blue)
Some predators
Tisbe sp.
Swarms over small fish, eats fins then devours the body as it drifts to the bottom

12. Subclass Copepoda - Cyclopoid
Most planktonic
most predators
some suspension feeders
Cyclops sp.

13. Subclass Copepod - Parasites
Ectoparasites
Psychrolutes sp (Fathead fish)
Endoparasites

14. Subclass Copepoda Fertilization is internal
indirect with spermatophore
Males usually smaller than females
Some brood eggs
Some release eggs into sea
Cyclops sp.

15. Subclass Copepoda Nauplius larva Copepodid larva
Nauplius larva
Copepodid larva
Freshwater forms can create cysts to protect them in winter.

16. Subclass Ostracoda (seed shrimps)
Found in freshwater and marine
swim or crawl
Most < 1mm
Gigantocypris 25mm
Enclosed in a bivalve shell but not hinged
Ostracods
Eye

17. Subclass Ostracoda (seed shrimps)
1st antennae used for sensory but sometimes digging
Swim (and sometimes walk) with 2nd antennae

18. Subclass Ostracoda (seed shrimps)
Nutrition
Most suspension feeders
some predators or scavengers
Gigantocypris sp is known to feed on fish
some deposit feeders

19. Subclass Ostracoda (seed shrimps)
Large fossil record
most extensive of any crustaceans
continuous from Cambrian period

20. Subclass Ostracoda (seed shrimps) - Reproduction
Most use bioluminescence to attact mates
Fertilization is internal and direct
some freshwater species are parthenogenic (like the Cladoceran Daphnia)
Nauplius larvae

21. Subclass Branchiura (fish lice)
Ectoparasites
marine and freshwater fish
In Argulus sp, large preoral spine connected to poison glands
Can swim
Copulation occurs on host but eggs deposited elsewhere
Suckers