Arthropoda
From Microcosm Aquarium Explorer
- Pycnogonid, sea spider. Ronald L. Shimek
- Neopetrolisthes maculata, porcelain crab. Scott W. Michael
- Saron marmoratus, Saron Shrimp. Scott W. Michael
- Enoplometopus sp., reef or flame lobster. Scott W. Michael
- Pyrgomatid or coral barnacles. Scott W. Michael
[edit] The Arthropods
Number of Living Species: Unknown.* (With the insects, estimated at 7-10 million.)
Common Characteristics: the most species-rich animal phylum on Earth (it includes the insects); perhaps the most successful phylum at adapting to both terrestrial and marine environments; segmented bodies covered with a proteinaceous exoskeleton, strengthened with chitin and calcium carbonate; jointed limbs serve various specialized functions as antennae, legs, pincers, or claws.
Note: some taxonomists now regard Arthropoda as a superphylum with four distinct phyla:
- the extinct Trilobites (Trilobita)
- the chelicerates (Chelicerata)
- the crustaceans (Crustacea)
- the insects, millipedes, and centipedes (Uniramia).
Noteworthy Behaviors: alternating leg movements; sense organs like hairs, bristles, and eyes permit monitoring of environment; dioecious reproduction.
[edit] Arachnids
Class Pycnogonida (Sea Spiders): 1,000 species Sea spiders occasionally enter marine aquariums on live rock, sea anemones, and coral colonies. They are often quite small, difficult to see and harmless to humans, although they may parasitize corals.
[edit] Crustaceans
Subphylum Crustacea (Copepods, Barnacles, Crabs, Shrimps, Lobsters): 39,000 species Class Malacostraca(Shrimps, Prawns, Lobsters, Crabs, Amphipods, Isopods): 22,000 species
[edit] Insects
Number of Living Species: 6-10 Million (Estimate)
Few insects make their way into aquaria, with the exception of food items, such as mosquito larvae, wingless fruit flies, and crickets for certain larger freshwater fishes.