ZOO 115 Invertebrate Zoology Phylum Arthropoda Subphylum Chelicerata

Subphylum Chelicerata n n Includes spiders, horseshoe crabs, seas spiders and scorpions Cephalothorax Have only two tagmata: cephalothorax and the abdomen Abdomen

Subphylum Chelicerata Cephalothorax bears 6 pairs of appendages n n n Chelicera are on the 2 nd cephalothorax segment Pedipalps 4 pr walking legs. Do not have antennae and deutocerebrum Abdomen has 12 or fewer segments Pedipalp Chelicerae

Subphylum Chelicerata Class Xiphosura n n n Horseshoe crabs Up to 75 cm (largest chelicerates) Live in marine shallow water on soft bottoms Omnivores Toxic (lethal) to Predators – saxotoxin in tissues Vestigial coelom = body cavity is hemocoel http: //www. globalclassroom. org/hcrab 2. jpg

Subphylum Chelicerata Class Xiphosura - Anatomy n 6 pair of appendages n n n 1 pr Chelicera 4 pr chelate legs 1 pr pusher legs Carapace Telson Chelate walking legs Compound eye Pusher leg http: //mainegov- Median eyes images. informe. org/dmr/rm/aquarium/teachers_guide/horseshoe_crab_dorsal_view. jpg

Subphylum Chelicerata Class Xiphosura - Feeding n n Uses chelate walking legs and chelicera to capture food. Transferred to the food groove Base of appendages are grinding surfaces (gnathobases) Spines on appendages move food to mouth Mouth Food http: //mainegov. Gnathobase images. informe. org/dmr/rm/aquarium/teachers_guide/horseshoe_crab_dorsal_view. jpg

Subphylum Chelicerata Class Xiphosura - Feeding n n n Mouth to crop Transferred to muscular toothed gizzard Moves to stomach Digestable material to digestive pouch Other material to intestine Solid waste outside via anus Intestine Stomach Gizzard Solid waste Crop Food Digestive pouch http: //mainegovimages. informe. org/dmr/rm/aquarium/teachers_guide/horseshoe_crab_in ternal_anatomy. jpg

Subphylum Chelicerata Class Xiphosura - Gas Exchange n n Water moves in through space between the abdominal plate and the carapace Then moves across gills and out Gills http: //mainegovimages. informe. org/dmr/rm/aquarium/teachers_guide/horseshoe_crab_internal_anatomy. jpg

Subphylum Chelicerata Class Xiphosura - Circulation n Blood flows into heart (via ostia) Pumped through arterial system Into hemocoel n Through gills n Back to heart n n Heart Pericardial sinus http: //mainegovimages. informe. org/dmr/rm/aquarium/teachers_guide/horseshoe_crab_in ternal_anatomy. jpg

Subphylum Chelicerata Class Xiphosura – Nervous system n n n Large brain Compound lateral eyes Pair of median pigment cup ocelli Rudimentary ventral eye Sensilla n n n mechanoreceptors chemorecepetors osmoreceptors

Subphylum Chelicerata Class Xiphosura – Reproduction n n n Gonochoric Sexual dimorphic – male smaller Mating during exceptionally high tides of full and new moons during Spring and Summer Female deposits 2000 -30000 eggs into sand Male fertilizes eggs Have a trilobite larva http: //www. lander. edu/rsfox/310 limulus. Lab_files/image 020. jpg

Subphylum Chelicerata – Class Arachnida n n n Includes spiders, scorpions, mites and ticks ~70, 000 described sp. but maybe a million more Mostly carnivores

Subphylum Chelicerata Class Arachnida - Anatomy n Appendages n Cheliceae n n Pedipalps n n Sometimes with poison or silk Many functions 4 pr walking legs Pedipalp Chelicera http: //www. rochedalss. eq. edu. au/spideran. gif Chelicera

Subphylum Chelicerata Class Arachnida - Digestion n Small digestive tube Digestion starts in preoral cavity formed by appendages and carapaceproteolytic enzymes Either the stomach or pharynx is a muscular pump http: //www. rochedalss. eq. edu. au/spideran. gif

Subphylum Chelicerata Class Arachnida –Circulation n n Trachae Book lungs

Subphylum Chelicerata Class Arachnida – Gas Exchange and circulation n Gas Exchange n n n Trachae Book lungs Circulation n n Hemocoel Book lungs Heart Arterial system Back to hemocoel http: //www. sci. sdsu. edu/classes/bio 201/book%20 lung. gif

Subphylum Chelicerata Class Arachnida – Excretion n Excrete quanine, adenine, xanthine or uric acid n n Allows little loss of water Two systems n n Nephridia Malphigian tubules

Subphylum Chelicerata Class Arachnida – Nervous system Brain http: //instruct 1. cit. cornell. edu/courses/bionb 424/students 2004/leb 27/CNSsmall. jpg

Subphylum Chelicerata Class Arachnida – Nervous system n Sensory n n Compound eyes – small but greater number Sensory setae – major sense organs n Mechanoreceptors n n Trichbothria – specialized for sensing weak air movement. Chemoreceptors Slit sense organs – strain gauges for cuticle No antennae but often equivalent on legs

Class Arachnida - Diversity n Order Scorpiones n n n 3 -21 cm in length Greatly enlarged pedipalps Very small chelicerae Stinger Predators – stay near burrow http: //www. thedailylink. com/thespiralburrow/anatomy/anat 02. html Can sting http: //www. regalreptile. com/scorpion%203. jpg within 0. 75 sec.

Class Arachnida - Diversity n Order Scorpiones n http: //www. thedailylink. com/thespiralburrow/anatomy/anat 02. html Gonochoric n n n n Mature – 6 yrs Extended courtship ritual Indirect sperm transfer – spermatophores Viviparous Care of young Direct development – months Live up to 25 yrs http: //cals. arizona. edu/pubs/insects/az 1320/Female-bark-scorpionalt. jpg http: //www. regalreptile. com/scorpion%203. jpg

Class Arachnida - Diversity n Order Uropygi n Whip scorpions or Vinegaroons n n n 80 mm in length Cephalothorax completely covered by carapace Pair anterior median eyes 3 -4 pairs lateral eyes Small chelicerae Large chelate pedipalps http: //www. petbugs. com/caresheets/gallery/M-giganteus. jpg

Class Arachnida - Diversity n Order Uropygi n n 2 pair book lungs Pair of large repugnatorial glands n n n 84% acetic acid and 5% caprylic acid 1 st leg acts as antennae Gonothropic n n Complex courship Indirect sperm transfer spermatophore http: //www. petbugs. com/caresheets/gallery/M-giganteus. jpg

Class Arachnida – Diversity Order Amblypygi n n n Whip spider 1 st legs – antennae All legs sensory Anatomy similar to spiders: n Chelicerae similar to spiders but lack poison glands. repugnatorial glands n No silk produced Tends to move laterally Indirect sperm transfer spermatophore http: //www. amnh. org/exhibitions/hall_tour/spectrum/specimens/ a 2395 h. jpg

Class Arachnida – Diversity Order Araenae n n n Spiders 0. 5 mm to 9 cm in length ~40, 000 described sp, ~130, 000 undescribed sp. Males usually smaller than females Three groups based n Most Primitive n Primitive chelicerae (only longitudinal movement) n Segmented abdomen n Primative n Primitive chelicerae n Advanced n Fangs can move to oppose each other

Class Arachnida – Diversity Order Araenae – Silk n What is it? n n Made of glycine, alanine and serine 6 -8 different kinds n n n 0. 003 mm thick Produced by n n n Cribellum Silk glands – different kinds Spinnerets n Single thread composed of many fibers which are weaved together Cribellum – not in all n n n 5 -6 used by any one spider http: //www. dmns. org/main/minisites/spiders/idkey 1. html Anterior to spinnerets Fine silk used for prey capture Spiders eat silk to reclaim it Silk glands Spinnerets //www. astrographics. com/Gallery. Prints/Display/GP 2017. jpg

Class Arachnida – Diversity Order Araenae – Silk n Function n Reproduction n n n Sperm web Egg case Nests http: //citybugs. tamu. edu/ Fast. Sheets/images/spiderballooning. gif Dragline Dispersion Prey capture (webs) http: //www. museums. org. za/bio/spiderweb/reproduction. htm http: //www. washington. edu/burkemuseum/spidermyth/images/ draglinethumb. jpg http: //typhoon. wcp. muohio. edu/tropicalvideos/c ostarica 03/spidereggcase 03. jpg

Class Arachnida – Diversity Order Araenae – Prey capture n Web builders n n n Orbs n Only the spiral is sticky n Walk on radial Tarantula n Built to catch specific types of insects n Affected by food Tunnel or Trapdoor http: //www. bushveld. co. za/pic tures-arachnids/garden-spiderlarge. jpg Hunting n n Heavier legs Good eyes in many http: //mamba. bio. uci. edu/~pjbryant/biodiv/spiders/Ap http: //www. 1000 plus. com/alex/Image. Gallery/Arachnids%20 honopelma%20 reversum. htm %20 Spiders/tn/Tunnel%20 Spider. jpg. html http: //www. coffee. co. uk/spiders. html http: //www. nancylynne. com/Spider% 20 Web%20 for%20 web. jpg

Class Arachnida – Diversity Order Araenae – Prey capture n n n Scopulae – walk up walls or glass Best developed slit sensors on legsvibration Eyes n n Main Secondary http: //dine. sanjuan. k 12. ut. us/heritage/land/animals/bugs/images/w olf_spider. jpg http: //www. dal. ca/~egingl/research. htm http: //research. amnh. org/entomology/blackrock 2/images/main_key/ scopulae_philodromidae. gif

Class Arachnida – Diversity Order Araenae – Prey capture n Fangs n n Movement http: //www. geocities. com/spiders_snakes/spider/fang. jpg Toxin n Hunters – cytotoxin n n antibiotics usually required no anti-venom anti-tetanus injection Some patients n In 3 days mild fever, headaches The above victim saw the Brown Recluse or Violin spider on her foot as she got out of the shower. This leg no longer exists because she had to have it amputated below the knee. http: //static. howstuffworks. com/gif/spider-fang. gif http: //www. museums. org. za/bio/spiderweb/bites. htm http: //www. brown-recluse. com/index. html? google 1

Class Arachnida – Diversity Order Araenae – Prey capture n Fangs n n Movement Toxin n Web-builders – neurotoxin n n n severe pain in the chest and abdomen anxiety, raised blood pressure breathing difficulties and heart palpitations nausea and vomiting sweating, excessive salivation and watery eyes a rash might develop Black Widow Trachoma Funnel-Web Spider LETHAL Atrax Funnel-Web spider LETHAL http: //acd. ufrj. br/mndi/Aracnologia/Trechona. htm http: //www. dobrodruh. cz/data/bookimg/00363 -atrax. jpg http: //library. thinkquest. org/C 007974/media/2_ 4 bla. jpg

Class Arachnida – Diversity Order Araenae – Prey capture n Fangs n n Movement Non-Toxic http: //www. ambergriscaye. com/pages/photos/art/tarantula. jpg

Class Arachnida – Diversity Order Araenae – Digestion n Either totally dissolve prey with enzymes or masticate Fluid sucked into midgut passing through particle filters Digested in Caeca

Class Arachnida – Diversity Order Araenae – Gas Exchange n n Book lungs And/or tracheae

Class Arachnida – Diversity Order Araenae – Reproduction n n Gonochoric Indirect sperm transfer n n No spermatophores Transferred by pedipalps n n Male spins sperm web (shown earlier) Deposits sperm on web Transfers sperm to pedipalps Pedipalps transfer sperm to female

Class Arachnida – Diversity Order Solifugae n n n n Sun spider ~800 species 2 mm – 7 cm Inhabit warm arid regions Enormous chelicerae No venom 1 st legs used as antennae Males extremely fast n Highly developed tracheae http: //www. key-net. net/users/swb/pet_arthropod/SS. jpg

Class Arachnida – Diversity Order Opilones Spider leg n n n Daddy long-legs or Harvestman ~5000 species 5 mm – 22 cm body No venom No constriction between cephalothorax and abdomen Long legs because of a multisegmented tarsus n n May have 100 s Eyes on Tubercle http: //troyb. com/photo/images/photos/00012918. jpg http: //www. thelensflare. com/large/spider_979. jpg http: //www. xs 4 all. nl/~ednieuw/Spiders/Info/spiderinfo. htm

Class Arachnida – Diversity Order Acari n n Ticks and mites ~40, 000 described n n n Gnathosoma 0. 1 – 0. 75 mm length n n >1, 000 undescribed http: //www. sdm. buffalo. edu/scic/toms_tick/tick-2_full. jpg Smallest can live in tracheae of honeybee Present in all habitats tagmata different No segmentation Entire body covered with single carapace Idiosoma Pedipalp http: //www. uky. edu/Agriculture/Entomology/entfacts/st ruct/amdogtik. gif

Class Arachnida – Diversity Order Acari n Large diversity in feeding n n n Carnivores Herbivores Scavengers Ectoparasites Endoparasites Chelicera Pedipalp http: //www. ijon. de/zecken/images/i-hex-wg. gif http: //www. uky. edu/Agriculture/Entomology/entfacts/st ruct/amdogtik. gif

Class Arachnida – Diversity Order Acari n Nervous system n Sensory setae n n n Air currents Heat Chemo Mechano Median and lateral eyes Slits on legs that may be analogous to slit sense organs http: //www. uky. edu/Agriculture/Entomology/entfacts/st ruct/amdogtik. gif

Class Arachnida – Diversity Order Acari n Reproduction n n Gonochoric Indirect sperm transfer by spermatophore Transferred by chelicera, male 3 rd pr. legs or female may pick up. Eggs in soil or humus 2 -6 wk incubation http: //www. uky. edu/Agriculture/Entomology/entfacts/st ruct/amdogtik. gif