1. Entomology 101 Arthropod Groups David J. Shetlar, Ph.D. The “BugDoc” The Ohio State University, OARDC & OSU Extension Columbus, OH © Sept, 2009, D.J. Shetlar, all rights reserved

2. Characteristics of the Phylum Arthropoda Coelomate protostomates that posses a segmented chitinous exoskeleton that must be shed during growth. Segments have paired appendages (e.g., legs, antennae) that are jointed. Segments are grouped into regions, called tagmata (e.g., head, thorax, abdomen). The nervous system is ventral The circulatory system is open and dorsal.

3. Arthropod Groups (taxa) The arthropods are divided into two large groups that exist today: The Chelicerates and The Mandibulates

4. Chelicerate Arthropod Characters: Pincher-like mouthparts - chelicerae - and pedipalps NO antennae Two body regions, usually - cephalothorax & abdomen Four pairs of legs Horseshoe crabs and arachnids are only living groups

5. Mandibulate Arthropod Characters: Mouthparts are mandibles - normally chewing sideways One or two pairs of antennae Various body region arrangements - cephalothorax & abdomen / head & trunk / head, thorax & abdomen Variable leg numbers Insects, crustaceans & myriapods

6. Classes of Arthropods: Chelicerates – Class Xiphosura – horseshoe crabs Class Arachnica – arachnids Mandibulates – Class Crustacea – crustaceans Class Diplopoda – millipedes Class Chilopoda – centipedes Class Symphyla – garden centipedes Class Hexapoda – insects

8. Class Arachnida 2 body regions Cephalothorax Abdomen

9. Major Orders of Arachnids Scorpiones - scorpions Pseudoscorpiones - false scorpions Opiliones - daddy-long-legs or harvestmen Acari - mites & ticks Araneae - spiders

10. Scorpion Tick (a mite) Pseudoscorpion Daddy-long-legs Wolf Spider

11. Order Scorpiones { pedipalps

13. chelicerae eyespedipalp

14. Pseudoscorpion

15. pedipalps & chelicerae cephalothorax abdomen Mite and Tick Body Regions

16. American dog tick male Blacklegged (deer) tick female

17. American dog tick female laying egg mass (1000-2000 eggs!).

18. Clover mites Twospotted spider mites Predatory mite

19. Opiliones (=daddy-long-legs, harvestmen) cephalothoraxabdomen

20. pedipalp chelicera (fang) cephalothorax abdomen narrow waist Spider Anatomy

21. Abdomen Pedipalp Chelicera (fang) Cephalothorax Jumping Spider

22. Wolf spider with egg caseSpitting spider Tarantula Orbweaving spider

23. Black widow with egg case Brown recluse (fiddleback)

24. Classes of Myriapods (many legged arthropods) (all have one pair of antennae, a head region, and trunk with many pairs of legs, use trachea) Diplopoda - millipedes Chilopoda - centipedes Symphyla - garden centipedes

25. Myriapods Millipede (Diplopoda) Two pair of legs per visible segment, attached under body. Centipede (Chilopoda) Pair of fangs under head, one pair legs per visible segment - attached to side of body. Symphylan (Symphyla) [garden centipede] No fangs, no eyes, legs attached to side of body. [one pair of antennae, head & trunk regions, trunk with many pairs of legs]

26. Millipede (Diplopoda) Centipede (Chilopoda) Garden centipede (Symphyla)

27. Classes of Crustacea (mostly marine, fresh water, a few terrestrial) (all have two pair of antennae, five or more pairs of legs, segmented abdominal appendages, head & trunk or cephalothorax & abdomen body arrangement, have gills) Isopoda - sowbugs or pillbugs Amphipoda - sand fleas, amphipods Cirripedia - barnicles Decapoda - crabs, lobster, shrimp several other minor orders

28. Crayfish External Morphology

29. Sowbugs (Isopoda), terrestrial crustaceans