Class INSECTA (=HEXAPODA)
Body is divided into head, thorax and abdomen. There is one pair of antennae, 3 pairs of legs and both compound and simple eyes. Respiration takes place with tracheal system and excretion with malpighian tubules. They are the only flying arthropods.
They are primitively wingless insects that have ectognathous mouth parts and also abdominal appendages. There is no metamorphosis during development and juveniles are similar to adults in morphology as well as habits. Ex. Telson-tails; Silverfish; Spring-tails; Campodea. There are 4 orders in this group.
They are winged insects or lost wings later in evolution. Mouth parts are endognathous and abdominal appendages are absent. Metamorphosis is either partial or complete with a pupal stage. Ex. Dragonflies, Grasshoppers; Termites; Lice; Cockroach; Beetles; Butterflies; Moths; Fleas; Ant-lions; Scorpion flies. There are 24 orders within this group.
Class CHILOPODA
Medium to large carnivorous animals that live beneath stones and logs and whose body is dorsoventrally flattened and divided into head and trunk. First maxillipede is modified as poison claw. One pair of mandibles and one or two pairs of maxillae are present. Respiration occurs through tracheal system and excretion with malpighian tubules. One pair of compound eyes and one pair of antennae are present. Ex. Scolopendra; Scutigera.
Class DIPLOPODA
Body is cylindrical, divided into head, collum and trunk. Trunk contains diplosegments with two pairs of legs and ostia. Last segment is legless and carries anus. Slow moving, herbivorous animals that contain repugnatorial glands on the skin to repel enemies. Ex. Julius; Glomeris; Spirobolus.
Class SYMPHYLA
Found in humus, they are 2.0-10.0 mm long agile arthropods that run about rapidly. Body is divided into head and 14-segmented trunk. Pygidium bears an oval telson and a pair of cerci. Spiracle is single pair on the first trunk segment. Eyes are absent and mouth parts are similar to insects. Ex. Scutigerella.
Class PAUROPODA
Soft bodied, grub-like arthropods, less than 2.0 mm long, having cylindrical body that contains 12 segments. Eyes are absent and antennae are 3-branched. Mandibles are for piercing and grinding. Found in soil and feed on humus and fungi. Ex. Pauropus.
ARTHROPODA CLASSIFICATION (After Ruppert & Barnes, 1994)
1. Subphylum TRILOBITOMORPHA – The Trilobites
2. Subphylum CHELICERATA – With chelicerae and pedipalps
Class Merostomata – ex. Limulus
Class Arachnida – Spiders, scorpions, mites and ticks
Class Pycnogonida – Sea spiders
3. Subphylum CRUSTACEA
Class Branchiopoda – fairy shrimps, brine shrimps
Class Maxillopoda – Copepods
Class Malacostraca – Prawn, Crabs, Lobsters, Shrimps
4. Subphylum UNIRAMIA
Class Insecta – Dragon flies, Cockroach, Beetles, Bugs, Butterflies
Class Chilopoda – Centipedes
Class Diplopoda – Millipedes
Class Symphyla – Soft bodied Scutigerella
Class Pauropoda – Soft bodied Pauropus
ARTHROPODA CLASSIFICATION (After Brusca & Brusca, 2003)
1. Subphylum TRILOBITOMORPHA (=TRILOBITA)
2. Subphylum CHELICERIFORMES
Class Chelicerata
Subclass Merostomata – Limulus
Subclass Arachnida – Spiders, Scorpions, Mites
Class Pycnogonida – Sea spiders
3. Subphylum CRUSTACEA
Class Remipedia – Lasionectes
Class Cephalocarida – Hutchinsoniella
Class Branchiopoda – Daphnia; Triops
Class Malacostraca – Squilla; Palaemon; Mysis; Cyamus; Crabs
Subclass Phyllocarida (1 order)
Subclass Eumalacostraca (15 orders)
Class Maxillopoda
Subclass Thecostraca – Ascothorax
Subclass Tantulocarida – Basipodella
Subclass Branchiura – Argulus
Subclass Pentastomida – Linguatula
Subclass Mystacocarida – Deirocheilocaris
Subclass Copepoda – Cyclops; Monstrilla; Ergasilus
Subclass Ostracoda – Cypris; Cypridina
4. Subphylum HEXAPODA
Class Entognatha – Orders: Protura, Diplura and Collembola
Class Insecta – 30 orders of insects
Subclass Archaeognatha – Bristle tails
Subclass Zygentoma – Silver fish
Subclass Pterygota – 28 orders. Mayflies, termites; cockroach etc.
5. Subphylum MYRIAPODA
Body contains head and long trunk bearing appendages. All are terrestrial with one pair of antennae. Compound eyes or simple eyes are present. Carnivore or herbivore animals, they include centipedes and millipedes.