Exercise 8 - Arthopoda

• Arthropods are bilaterally symmetrical, segmented animals whose body is encased in a hardened and usually chitinous exoskeleton.
• This fusion of segments into specialized regions is called tagmatization, and each body region is called tagmata.
• What are the subphylum under Phylum Arthropoda?

  1. Subphylum Trilobita
  2. Subphylum Chelicerta
  3. Subphylum Crustacea
  4. Subphylum Myriapoda
  5. Subphylum Hexapoda
• Subphylum Trilobite – all extinct forms, two longitudinal furrows divide the body into three lobes; distinct head, thorax abdomen; biramous appendages.
• Subphylum Chelicerata – first pairs of appendage chelicerae; pair of pedipalps and four pairs of legs; no antennae, no mandibles; with cephalothorax abdomen.
• What are classes under Subphylum Chelicerata?

  Arachnida, Merostomata, and Pycnogonida (sea spiders).
• Class Merostomata (eurypterids or horseshoecrabs) - aquatic chelicerates. Cephalothorax and abdomen; compound lateral eyes; appendages with gills; sharp telson.
• Class Arachnida- scorpions, spiders, mites, ticks, harvestmen. Four pairs of legs; segmented or unsegmented abdomen with or without appendages and generally distinct from cephalothorax; respiration by gills, tracheae, or book lungs; excretion by Malpighian tubules or coxal glands.
• What are the orders under Class Arachnida?

  Araneae (spiders), Scorpiones (scorpions), Opiliones (harvestmen), Acari (ticks and mites)
• Subphylum Crustacea - mostly aquatic, with gills; cephalothorax usually with carapace; biramous appendages; two pairs of antennae, one pair of mandibles, and two pairs of maxillae; usually dioecious.
• What are the classes under Subphylum Crustacea?

  Malacostraca, Maxillopoda, and Branchiopoda.
• Class Branchiopoda (Shrimp) - represents a primitive crustacean-type, mostly freshwater, reproduction resembling rotifers.
• Class Maxillopoda – no appendages on abdomen, unique maxillopodan eye in nauplius larva.
• Class Malacostraca - lobsters, crayfish, crabs, etc. Usually with five segments in the head; eight in the thorax and six in the abdomen; legs paired.
• What are the orders under Class Branchiopoda?

  1. Order Anostraca (fairly shrimp)
  2. Order Notostraca (tadpole shrimp)
  3. Order Conchostraca (clam shrimp)
  4. Order Diplostraca (water flease ' Daphnia)
• What are the subclasses under Class Maxillopoda?

  Copepoda and Cirripedia (barnacles).
• Subclass Copepoda – typically with six pairs of thoracic legs, carapace absent, marine and freshwater, free- swimming or parasitic.
• Subclass Thecostraca, Infraclass Cirripedia - adults are sessile, carapace enclosing the body, mostly hermaphroditic, six pairs of trunk limbs with calcareous plates, marine with eight biramous appendages.
• Subphylum Myriapoda - all appendages uniramous, body divided into head and trunk, one pair of antennae, one pair mandibles.
• What are the classes under Subphylum Myriapoda?

  Class Diplopoda and Class Chilopoda
• Class Diplopoda (millipedes) - herbivores; two pairs of legs per segment; first body segment is legless; mandibles and gnathochilarium comprise the mouthparts; reproductive ducts open anteriorly.
• Class Chilopoda (centipedes) - carnivorous with one pair of legs per segment; the first pair modified as poison claw; mouthparts incomplete but with mandible and maxillae; reproductive ducts open posteriorly.
• Subphylum Hexapoda - all appendages uniramous; one pair of antennae, one pair of mandibles, two pairs of maxillae, three pairs of legs.
• Class Insecta - body with distinct head, thorax and abdomen, pair of antennae; mouthparts modified for different food habits; the most diverse class among all phyla and kingdoms.
• Subphylum Chelicerata

  Representative species:

  • Tachypleus (C. Merostomata) - The horseshoe crab lives in shallow marine water and is abundant in Palawan. They swim awkwardly by means of their abdominal plates and walk on their four pairs of walking legs. They feed at night on worms and small mollusks.
• Subphylum Chelicerata

  Representative species:

  • Dermacentor - dog tick (C. Arachnida O. Acari) - The tick is an ectoparasite that feeds on the blood of vertebrates and is a carrier of protozoan and bacterial diseases. A species of Dermacentor, for instance, carries a bacterium that causes tularemia and relapsing fever.
• Subphylum Chelicerata

  Representative species:

  • Boophilus  - cattle  tick (C. Arachnida O. Acari) - Like  the Dermacentor, the cattle tick lacks distinct body regions. Compare the cattle tick with the dog tick and label the parts.
• Subphylum Chelicerata

  Representative species:

  • Lycosa (C. Arachnida O. Araneae) - The wolf spider is a predaceous, insect-feeding arachnid that uses its chelicerae as fangs. Unlike other spiders which spin web for traps, it chases its prey.
• Subphylum Crustacea

  Representative species:

  • Thermocyclops (C. Maxillopoda) - This copepod can be found in standing freshwater. Ecologically, copepods are of great importance as they dominate the primary consumer level in aquatic communities.
• Subphylum Crustacea

  Representative species:

  • Balanus (C. Maxillopoda O. Cirripedia) - Barnacles are sessile as adults. Once thought to be mollusks, they are in fact closely related to crabs and shrimps. They are attached to the substrate which may be rocks, shells of other crustaceans and mollusks, submerged timber and even ship bottoms.
• Subphylum Crustacea

  Representative species:

  • Squilla (C. Branchiopoda) - The mantis shrimp is a predator in tropical marine habitats that spend most of its life in burrows. Mantis shrimps have powerful raptorial claws that they use to attack and kill prey by spearing or stabbing them. Other species have claws that end in clubs used to bludgeon their prey.
• Subphylum Crustacea

  Representative species:

  • Portunus (C. Malacostraca) - This edible marine crab (blue crab) is locally known as “alimasag”.
• Subphylum Crustacea

  Representative species:

  • Penaeus (C. Malacostraca) - The marine prawn is commonly known as the sugpo.
• Subphylum Crustacea

  Representative species:

  • Moina (C. Branchipoda) - This pinkish water flea is obtained from standing freshwater bodies and extensively fed to aquarium fishes.
• Subphylum Myriapoda

  Representative species:

  • Millipede (C. Diplopoda) - A distinguishing feature of the millipede is the presence of double trunk segments derived from the fusion of two originally separate somites.
• Subphylum Myriapoda

  Representative species:

  • Scolopendra (C. Chilooda) - The centipedes are slender segmented forms. They live in humid places and actively prey on other arthropods at night.
• Subphylum Hexapoda

  Representative species:

  • Melicoides (grasshopper) - The grasshopper is a representative winged insect. It occurs worldwide, mainly in open grasslands where they eat leafy vegetation.
• Subphylum Hexapoda

  Representative species:

  • Pediculus - The human louse is a wingless ectoparasitic insect that feed in human blood. There are two subspecies of the human louse which are the head louse that lives in the scalp and the body louse that lays its eggs on clothing.
• Subphylum Hexapoda

  Representative species:

  • Ctenocephalides - The flea is a jumping, blood-sucking, wingless insect. The body is compressed laterally for easy movement through the fur of the host.
• What is the class and order of the picture below?

  Spider, Class Arachnida, Order Araneae