1. Classification- Phylum Arthropoda Chapter 19 Subphylum Trilobita (extinct) Subphylum Trilobita (extinct) Subphylum Chelicerata Subphylum Chelicerata Class Arachnida Class Arachnida Order Araneae Order Araneae Order Scorpiones Order Scorpiones Order Opiliones (Daddy Longlegs) Order Opiliones (Daddy Longlegs) Order Acari (Ticks and Mites) Order Acari (Ticks and Mites) Subphylum Myriapoda Subphylum Myriapoda Class Diplopoda Class Diplopoda Class Chilopoda Class Chilopoda Chapter 20 Subphylum Crustacea Subphylum Crustacea Chapter 21 Subphylum Hexapoda Subphylum Hexapoda

2. 19-2 CHAPTER 19 Trilobites, Chelicerates, and Myriapods Trilobites, Chelicerates, and Myriapods

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4. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 19-4 Characteristics Anthropodization Soft cuticle of the arthropod ancestors was stiffened by deposition of protein and chitin Soft cuticle of the arthropod ancestors was stiffened by deposition of protein and chitin Joints had to provide flexibility Joints had to provide flexibility Sequence of molts was necessary to allow for growth Sequence of molts was necessary to allow for growth Molting required hormonal control Molting required hormonal control Hydrostatic skeleton function was lost Hydrostatic skeleton function was lost Coelom regressed and was replaced by open sinuses Coelom regressed and was replaced by open sinuses Motile cilia were lost Motile cilia were lost

5. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 19-5 Phylum Arthropoda Contains over 3/4 of all known species Contains over 3/4 of all known species Coelomate protostomes with well-developed organ systems Coelomate protostomes with well-developed organ systems Segmented Segmented Characteristics

6. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 19-6 Sizes range from the Japanese crab (four meters in leg span) to the 0.1 mm long follicle mite Sizes range from the Japanese crab (four meters in leg span) to the 0.1 mm long follicle mite Abundance and wide ecological distribution makes them the most diverse animal group Abundance and wide ecological distribution makes them the most diverse animal group Some are agents of disease and compete with humans for food Some are agents of disease and compete with humans for food Others are beneficial Others are beneficial All modes of feeding occur among arthropods; carnivores, omnivores, herbivorous (most), decomposers, scavengers, parasites, etc. All modes of feeding occur among arthropods; carnivores, omnivores, herbivorous (most), decomposers, scavengers, parasites, etc. Characteristics

7. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Japanese Spider Crap Follicle Mite

8. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 19-8 Relationships among arthropod subgroups Divided into subphyla based on relationships between subgroups Divided into subphyla based on relationships between subgroups Groupings among subphyla based on molecular data Groupings among subphyla based on molecular data Centipedes, millipedes are placed into subphylum Myriapoda Centipedes, millipedes are placed into subphylum Myriapoda Insects are placed in subphylum Hexapoda Insects are placed in subphylum Hexapoda Spiders, and ticks form subphylum Chelicerata Spiders, and ticks form subphylum Chelicerata Lobsters, crabs, barnacles, and others form subphylum Crustacea Lobsters, crabs, barnacles, and others form subphylum Crustacea Characteristics

9. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 19-9 2 Important Parts in Arthropods: Appendages and Mouthparts Uniramous: single branched Biramous: 2 branches Chelicerae: pointed appendages to grasp food Mandible: chewing appendage

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11. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 19-11 Great Diversity and Abundance of Arthropods WHY HAVE ARTHROPODS SURVIVED… 1. Versatile Exoskeleton 1. Versatile Exoskeleton Cuticle is highly protective and jointed, providing mobility Cuticle is highly protective and jointed, providing mobility Consists of inner thick procuticle and outer thin epicuticle Consists of inner thick procuticle and outer thin epicuticle Procuticle has an exocuticle secreted before a molt and an endocuticle secreted after molting Procuticle has an exocuticle secreted before a molt and an endocuticle secreted after molting Both layers of procuticle contain chitin bound with protein Both layers of procuticle contain chitin bound with protein Procuticle is lightweight, flexible, and protects against dehydration Procuticle is lightweight, flexible, and protects against dehydration

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13. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 19-13 Cuticle is further hardened by tanning Cuticle is further hardened by tanning Ecdysis, or molting Ecdysis, or molting Process of shedding outer covering and growing a new, larger one Process of shedding outer covering and growing a new, larger one Arthropods typically molt four to seven times Arthropods typically molt four to seven times Great Diversity and Abundance of Arthropods

14. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 19-14 2. Segmentation and Appendages for Efficient Locomotion 2. Segmentation and Appendages for Efficient Locomotion Appendages often highly specialized for division of labor Appendages often highly specialized for division of labor Limb segments are hollow levers with internal striated muscles Limb segments are hollow levers with internal striated muscles Appendages may function in sensing, food handling, walking, or swimming Appendages may function in sensing, food handling, walking, or swimming 3. Use of Diverse Resources through Metamorphosis 3. Use of Diverse Resources through Metamorphosis Many arthropods undergo metamorphic changes leading to different larval and adult stages Many arthropods undergo metamorphic changes leading to different larval and adult stages Larvae and adults feed on different organisms and occupy different habitats Larvae and adults feed on different organisms and occupy different habitats Avoid competition Avoid competition Survival of Arthropods

15. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 19-15 4. Air Piped Directly to Cells 4. Air Piped Directly to Cells Terrestrial arthropods Terrestrial arthropods Use an efficient tracheal system for oxygen transport directly to tissues Use an efficient tracheal system for oxygen transport directly to tissues Aquatic arthropods Aquatic arthropods Respire via various forms of gills Respire via various forms of gills 5. Highly Developed Sensory Organs 5. Highly Developed Sensory Organs Eyes vary from simple light sensitive ocelli to a compound mosaic eye Eyes vary from simple light sensitive ocelli to a compound mosaic eye Other sensory structures for touch, smell, hearing, balancing, and chemical reception Other sensory structures for touch, smell, hearing, balancing, and chemical reception Survival of Arthropods

16. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 19-16 Early Arthropod fossils: Trilobites and Eurypterid

17. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 19-17 Subphylum Chelicerata Characteristics Chelicerates have six pairs of cephalothoracic appendages including chelicerae (eating), pedipalps (mating) and four pair of legs Chelicerates have six pairs of cephalothoracic appendages including chelicerae (eating), pedipalps (mating) and four pair of legs Lack mandibles and antennae Lack mandibles and antennae Most suck liquid food from prey Most suck liquid food from prey Example: spiders, horseshoe crabs, sea spiders, ticks, scorpions Example: spiders, horseshoe crabs, sea spiders, ticks, scorpions

18. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 19-18 Sea Spiders Horseshoe Crabs

19. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 19-19 Horseshoe Crab: Illustrating 6 pairs of appendages

20. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 19-20 Sea spiders: Illustrating 6 sets of appendages

21. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 19-21 Class Arachnida Great diversity Great diversity Most are free living and more common in warm, dry regions Most are free living and more common in warm, dry regionsStructures Divided into two body parts: a cephalothorax and an abdomen Divided into two body parts: a cephalothorax and an abdomen Cephalothorax bears a pair of chelicerae, a pair of pedipalps, and 4 pairs of walking legs Cephalothorax bears a pair of chelicerae, a pair of pedipalps, and 4 pairs of walking legs No antenna and mandibles No antenna and mandibles Example: Spiders, Ticks, and Scorpions Example: Spiders, Ticks, and Scorpions Subphylum Chelicerata

22. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 19-22 Most are predaceous and have claws, fangs, poison glands, or stingers Most are predaceous and have claws, fangs, poison glands, or stingers Sucking mouthparts ingest fluids and soft tissues from bodies of their prey Sucking mouthparts ingest fluids and soft tissues from bodies of their prey Spiders have spinning glands Spiders have spinning glands Pedipalps of males are modified, sometimes elaborately, for sperm transfer Pedipalps of males are modified, sometimes elaborately, for sperm transfer Subphylum Chelicerata

23. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 19-23 Over 80,000 species have been described Over 80,000 species have been described Most harmless to humans and provide essential control of injurious insects Most harmless to humans and provide essential control of injurious insects Some spiders are venomous and can cause pain or death in humans Some spiders are venomous and can cause pain or death in humans Ticks may carry human diseases Ticks may carry human diseases Mites can be crop pests Mites can be crop pests Subphylum Chelicerata

24. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 19-24 Order Araneae: Spiders Approximately 40,000 species Approximately 40,000 species Body consists of an unsegmented cephalothorax and abdomen joined by a slender pedicel Body consists of an unsegmented cephalothorax and abdomen joined by a slender pedicel Anterior appendages are a pair of chelicerae with terminal fangs Anterior appendages are a pair of chelicerae with terminal fangs Pair of pedipalps have sensory functions and are used by males to transfer sperm Pair of pedipalps have sensory functions and are used by males to transfer sperm Basal parts of pedipalps used to handle food Basal parts of pedipalps used to handle food Four pairs of walking legs terminate in claws Four pairs of walking legs terminate in claws All are predaceous, mostly on insects All are predaceous, mostly on insects Subphylum Chelicerata

25. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 19-25 External Anatomy of Jumping Spider

26. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 19-26 Injected venom liquefies and digests the tissues which is sucked into spider’s stomach Injected venom liquefies and digests the tissues which is sucked into spider’s stomach RESPIRATORY SYSTEM RESPIRATORY SYSTEM Breathe by book lungs and/or trachea Breathe by book lungs and/or trachea Book lungs unique to spiders Book lungs unique to spiders Parallel air pockets extend into blood-filled chamber Parallel air pockets extend into blood-filled chamber Air enters chamber through a slit in body wall Air enters chamber through a slit in body wall Trachea system Trachea system Transports air directly to tissues/blood through an opening called a spiracle Transports air directly to tissues/blood through an opening called a spiracle Excretory System Excretory System In spiders and insects, Malpighian tubules serve as excretory structures In spiders and insects, Malpighian tubules serve as excretory structures Rectal glands reabsorb water. Conserves water and allows the organisms to live in dry environments Rectal glands reabsorb water. Conserves water and allows the organisms to live in dry environments Subphylum Chelicerata

27. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 19-27 Internal Anatomy of a Spider

28. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 19-28 Sensory Systems Sensory Systems Most spiders have eight simple eyes, each with a lens, optic rods, and a retina Most spiders have eight simple eyes, each with a lens, optic rods, and a retina Detect movement and may form images Detect movement and may form images Sensory setae detect air currents, web vibrations, and other stimuli Sensory setae detect air currents, web vibrations, and other stimuli Vision is poor, rely on mechanoreceptors (stimuli) Vision is poor, rely on mechanoreceptors (stimuli) Subphylum Chelicerata

29. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 19-29 Web-Spinning Habits Web-Spinning Habits Spinning silk critical ability for spiders Spinning silk critical ability for spiders Two or three pairs of spinnerets contain microscopic tubes that run to silk glands Two or three pairs of spinnerets contain microscopic tubes that run to silk glands Liquid scleroprotein secretion hardens as it is extruded from spinnerets Liquid scleroprotein secretion hardens as it is extruded from spinnerets Silk threads are very strong and will stretch considerably before breaking Silk threads are very strong and will stretch considerably before breaking Silk is used for orb webs, lining burrows, forming egg sacs, and wrapping prey Silk is used for orb webs, lining burrows, forming egg sacs, and wrapping prey Subphylum Chelicerata

30. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 19-30 Grasshopper snared in Golden Garden Spider silk. If the spider is not hungry, it will save the live prey for later.

31. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Fisher Spider: Catches prey, paralyzes them, pumps in digestive enzymes, then sucks out predigested contents.

32. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 19-32 Reproduction Reproduction Before mating, male stores sperm in pedipalps Before mating, male stores sperm in pedipalps Mating involves inserting pedipalps into the female genital openings Mating involves inserting pedipalps into the female genital openings A courtship ritual is often required before the female will allow mating A courtship ritual is often required before the female will allow mating Eggs may develop in a cocoon in the web or may be carried by female Eggs may develop in a cocoon in the web or may be carried by female Young hatch in about two weeks and may molt before leaving the egg cocoon Young hatch in about two weeks and may molt before leaving the egg cocoon Subphylum Chelicerata

33. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 19-33 Wolf spider with egg sack Black Widow with egg sack

34. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 19-34 Are spiders really dangerous? Are spiders really dangerous? Most people fear spiders without good reason Most people fear spiders without good reason Spiders are allies of humans in our battle with insects Spiders are allies of humans in our battle with insects American tarantulas rarely bite, and bite is not dangerous American tarantulas rarely bite, and bite is not dangerous Species of black widow spiders are dangerous Species of black widow spiders are dangerous Venom is neurotoxic Venom is neurotoxic Brown recluse spider Brown recluse spider Hemolytic venom that destroys tissue around the bite Hemolytic venom that destroys tissue around the bite Some Australian and South American spiders are the most dangerous and aggressive Some Australian and South American spiders are the most dangerous and aggressive Subphylum Chelicerata

35. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 19-35 Tarantula: Not Dangerous. Bite similar to Bee Sting Bite when threatened or defending eggs/young.

36. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 19-36 A: Black Widow displaying Red Hourglass B: Brown Recluse Spider displaying violin marking on cephalothorax

37. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 19-37 Order Scorpionida: Scorpions More common in tropical and subtropical zones but occur in temperate areas More common in tropical and subtropical zones but occur in temperate areas Approximately 1,400 species worldwide Approximately 1,400 species worldwide Nocturnal and feed largely on insects and spiders Nocturnal and feed largely on insects and spiders Sand-dwellers locate prey by detecting surface waves with leg sensillae Sand-dwellers locate prey by detecting surface waves with leg sensillae Appendages attached to cephalothorax Appendages attached to cephalothorax Pair of medial eyes and 2–5 lateral eyes Pair of medial eyes and 2–5 lateral eyes Preabdomen has 7 segments Preabdomen has 7 segments Postabdomen has long, slender tail of five segments that ends in a stinging apparatus Postabdomen has long, slender tail of five segments that ends in a stinging apparatus Subphylum Chelicerata

38. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 19-38 Emperor Scorpion with young. Young stay with mother until their first molt. Harvestmen: Order Opiliones AKA- Daddy Longlegs

39. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 19-39 Under the abdomen are comblike pectines Under the abdomen are comblike pectines Explore the ground and aid in sex recognition Explore the ground and aid in sex recognition Stinger on last segment has venom that varies from mildly painful to dangerous Stinger on last segment has venom that varies from mildly painful to dangerous Ovoviviparous or viviparous and produce from 6 to 90 young Ovoviviparous or viviparous and produce from 6 to 90 young Perform complex mating dances Perform complex mating dances In some species the male stings the female on pedipalp or on edge of cephalothorax In some species the male stings the female on pedipalp or on edge of cephalothorax Subphylum Chelicerata

40. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 19-40 Order Opiliones: Harvestmen Harvestmen or daddy longlegs Harvestmen or daddy longlegs Approximately 5,000 species worldwide Approximately 5,000 species worldwide Unlike spiders, abdomen and cephalothorax join broadly without a narrow pedicel Unlike spiders, abdomen and cephalothorax join broadly without a narrow pedicel Can lose most of their eight long legs without ill effect Can lose most of their eight long legs without ill effect Chelicerae are pincerlike Chelicerae are pincerlike Mostly scavengers Mostly scavengers Have 2 eyes, not 8 Have 2 eyes, not 8 Subphylum Chelicerata

41. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 19-41 Order Acari: Ticks and Mites Medically and economically the most important arachnids Medically and economically the most important arachnids About 30,000 species have been described About 30,000 species have been described Both aquatic and terrestrial Both aquatic and terrestrial Inhabit deserts, polar areas, and hot springs Inhabit deserts, polar areas, and hot springs Most mites are less than 1 millimeter long Most mites are less than 1 millimeter long Ticks may range up to 2 cm Ticks may range up to 2 cm Complete fusion of cephalothorax and abdomen Complete fusion of cephalothorax and abdomen No sign of external segmentation No sign of external segmentation Subphylum Chelicerata

42. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 19-42 Mouthparts on tip of the anterior capitulum Mouthparts on tip of the anterior capitulum Chelicerae on each side help pierce, tear, or grip food Chelicerae on each side help pierce, tear, or grip food Adult mites and ticks possess 4 pairs of legs Adult mites and ticks possess 4 pairs of legs Transfer sperm directly or by spermatophores (packets of sperm) Transfer sperm directly or by spermatophores (packets of sperm) Egg hatches, releasing a six-legged larva Egg hatches, releasing a six-legged larva Eight-legged nymph stages follow Eight-legged nymph stages follow Subphylum Chelicerata

43. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 19-43 Wood Tick All stages are ectoparasites Red Velvet Mite: Trombicula Only Larvae is ectoparasite

44. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 19-44 House dust mites House dust mites Free-living and often cause allergies Free-living and often cause allergies Spider mites Spider mites One of many important agricultural pest mites that suck out plant nutrients One of many important agricultural pest mites that suck out plant nutrients Chiggers Chiggers Larval Trombicula mites Larval Trombicula mites Feed on dermal tissues and cause skin irritation Feed on dermal tissues and cause skin irritation Hair follicle mite Demodex Hair follicle mite Demodex Harmless but may cause mild dermatitis Harmless but may cause mild dermatitis Subphylum Chelicerata

45. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 19-45 Human Follicle Mite

46. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 19-46 Human itch mite Human itch mite Causes intense itching Causes intense itching Popular in WWII - due to crowded conditions in which people lived Popular in WWII - due to crowded conditions in which people lived Subphylum Chelicerata Human Itch Mite

47. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Subphylum Chelicerata Ticks: 2nd premier disease vector (after mosquito). Ticks: 2nd premier disease vector (after mosquito). Species include: Species include: Ixodes Ixodes Some carry Lyme disease Some carry Lyme disease Bacterial infection dicovered in 1970, in the city of Lyme, Bacterial infection dicovered in 1970, in the city of Lyme, Conneticut. Conneticut. Dermacentor Dermacentor Transmit Rocky Mountain spotted fever Transmit Rocky Mountain spotted fever Cattle tick Cattle tick Transmits Texas cattle fever (Protozoan) Transmits Texas cattle fever (Protozoan)

48. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 19-48 Tick: Carries Texas Cattle Fever

49. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 19-49 Subphylum Myriapoda Characteristics Myriopods (“Many Footed”) include: Myriopods (“Many Footed”) include: Chilopoda (centipedes) Chilopoda (centipedes) Diplopoda (millipedes) Diplopoda (millipedes) Use trachea to transport respiratory gases to all body tissue Use trachea to transport respiratory gases to all body tissue Excretion usually by Malpighian tubules Excretion usually by Malpighian tubules

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51. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 19-51 Class Chilopoda Centipedes Centipedes Found under logs, bark and stones Found under logs, bark and stones Carnivorous, eating earthworms, cockroaches, and other insects Carnivorous, eating earthworms, cockroaches, and other insects Centipedes usually have one pair of legs on each segment Centipedes usually have one pair of legs on each segment Most harmless to humans Most harmless to humans Few large, tropical centipedes are dangerous Few large, tropical centipedes are dangerous Approximately 3,000 species worldwide Approximately 3,000 species worldwide Subphylum Myriapoda

52. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 19-52 Centipede from Amazon, Peru.Head of a Centipede

53. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 19-53 Characteristics Terrestrial and have flattened bodies with up to 177 segments Terrestrial and have flattened bodies with up to 177 segments Each segment except the one behind the head and last two Each segment except the one behind the head and last two Bears a pair of jointed legs Bears a pair of jointed legs Appendages of first body segment form poison claws Appendages of first body segment form poison claws Head has one pair of antennae Head has one pair of antennae Eyes on either side of the head consist of groups of ocelli Eyes on either side of the head consist of groups of ocelli Subphylum Myriapoda

54. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 19-54 Reproduction Sexes separate with unpaired gonads and paired ducts Sexes separate with unpaired gonads and paired ducts Some lay eggs and others are viviparous Some lay eggs and others are viviparous Young resemble adults and do not undergo metamorphosis Young resemble adults and do not undergo metamorphosis Subphylum Myriapoda

55. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 19-55 Class Diplopoda Millipedes (double footed) Millipedes (double footed) Less active than centipedes Less active than centipedes Walk with graceful rather than wriggling motion Walk with graceful rather than wriggling motion Most eat decayed plants but a few eat living plant tissue Most eat decayed plants but a few eat living plant tissue Most are slow moving and roll into a coil for defense Most are slow moving and roll into a coil for defense Some secrete toxic or repellant fluids from special glands on side of body Some secrete toxic or repellant fluids from special glands on side of body More than 10,000 species of worldwide More than 10,000 species of worldwide Subphylum Myriapoda

56. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 19-56 Tropical millipede. Head of a Millipede

57. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 19-57 Characteristics Cylindrical bodies with 25 to more than 100 segments Cylindrical bodies with 25 to more than 100 segments Short thorax consists of 4 segments, each bearing one pair of legs Short thorax consists of 4 segments, each bearing one pair of legs Each abdominal segment has 2 sets of legs Each abdominal segment has 2 sets of legs Head has 2 clusters of simple eyes and a pair each of antennae and mandibles Head has 2 clusters of simple eyes and a pair each of antennae and mandibles Subphylum Myriapoda

58. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 19-58 Reproduction Appendages of seventh segment specialized as copulatory organs Appendages of seventh segment specialized as copulatory organs After copulation, female lays eggs in a nest and guards them After copulation, female lays eggs in a nest and guards them Larvae have only one pair of legs per segment Larvae have only one pair of legs per segment Subphylum Myriapoda

59. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 19-59 Classification- Phylum Arthropoda Subphylum Trilobita (extinct) Subphylum Trilobita (extinct) Subphylum Chelicerata Subphylum Chelicerata Class Arachnida Class Arachnida Order Araneae Order Araneae Order Scorpiones Order Scorpiones Order Opiliones (Daddy Longlegs) Order Opiliones (Daddy Longlegs) Order Acari (Ticks and Mites) Order Acari (Ticks and Mites) Subphylum Myriapoda Subphylum Myriapoda Class Diplopoda Class Diplopoda Class Chilopoda Class Chilopoda Subphylum Crustacea Subphylum Crustacea Subphylum Hexapoda Subphylum Hexapoda Classification