zoo 115 invertebrate zoology phylum arthropoda subphylum chelicerata
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ZOO 115 Invertebrate Zoology
Phylum Arthropoda
Subphylum Chelicerata
Subphylum Chelicerata
Includes spiders, horseshoe crabs, seas spiders and scorpions
Have only two tagmata: cephalothorax and the abdomen
Cephalothorax
Abdomen
Subphylum Chelicerata
Cephalothorax bears 6 pairs of appendages
Chelicera are on the 2nd cephalothorax segment
Pedipalps 4 pr walking legs. Do not have
antennae and deutocerebrum
Abdomen has 12 or fewer segments
Pedipalp
Chelicerae
Subphylum ChelicerataClass Xiphosura
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/hcrab2.jpg
http://mainegov-images.informe.org/dmr/rm/aquarium/teachers_guide/horseshoe_crab_dorsal_view.jpg
Telson
Carapace
Compound eye Median eyes
Subphylum Chelicerata Class Xiphosura - Anatomy
6 pair of appendages 1 pr
Chelicera 4 pr chelate
legs 1 pr pusher
legs
Chelate walking legs
Pusher leg
http://mainegov-images.informe.org/dmr/rm/aquarium/teachers_guide/horseshoe_crab_dorsal_view.jpg
Subphylum ChelicerataClass Xiphosura - Feeding 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
Gnathobase
Mouth
Food
Subphylum ChelicerataClass Xiphosura - Feeding
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
http://mainegov-images.informe.org/dmr/rm/aquarium/teachers_guide/horseshoe_crab_internal_anatomy.jpg
Food
Crop
StomachGizzard
Digestive pouch
Solid waste
Intestine
Subphylum Chelicerata Class Xiphosura - Gas Exchange
Water moves in through space between the abdominal plate and the carapace
http://mainegov-images.informe.org/dmr/rm/aquarium/teachers_guide/horseshoe_crab_internal_anatomy.jpg
Gills Then moves across gills and out
Subphylum Chelicerata Class Xiphosura - Circulation
Blood flows into heart (via ostia)
http://mainegov-images.informe.org/dmr/rm/aquarium/teachers_guide/horseshoe_crab_internal_anatomy.jpg
Pericardial sinusHeart
Pumped through arterial system
Back to heart
Into hemocoel
Through gills
Subphylum ChelicerataClass Xiphosura – Nervous system
Large brain Compound lateral eyes Pair of median pigment cup ocelli Rudimentary ventral eye Sensilla
mechanoreceptors chemorecepetors osmoreceptors
Subphylum ChelicerataClass Xiphosura – Reproduction
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/310limulusLab_files/image020.jpg
Subphylum Chelicerata – Class Arachnida
Includes spiders, scorpions, mites and ticks
~70,000 described sp. but maybe a million more
Mostly carnivores
Subphylum ChelicerataClass Arachnida - Anatomy
Appendages Cheliceae
Sometimes with poison or silk
Pedipalps Many
functions
4 pr walking legs http://www.rochedalss.eq.edu.au/spider/spideran.gif
Pedipalp
Chelicera
CheliceraPedipalp
Subphylum ChelicerataClass Arachnida - Digestion
Small digestive tube
Digestion starts in preoral cavity formed by appendages and carapace- proteolytic enzymes
Either the stomach or pharynx is a muscular pump http://www.rochedalss.eq.edu.au/spider/spideran.gif
Subphylum ChelicerataClass Arachnida –Circulation
Trachae Book lungs
Subphylum ChelicerataClass Arachnida – Gas Exchange and circulation Gas Exchange
Trachae Book lungs
Circulation Hemocoel Book lungs Heart Arterial
system Back to
hemocoelhttp://www.sci.sdsu.edu/classes/bio201/book%20lung.gif
Subphylum ChelicerataClass Arachnida – Excretion
Excrete quanine, adenine, xanthine or uric acid Allows little loss of water
Two systems Nephridia Malphigian tubules
Subphylum ChelicerataClass Arachnida – Nervous system
http://instruct1.cit.cornell.edu/courses/bionb424/students2004/leb27/CNSsmall.jpg
Brain
Subphylum ChelicerataClass Arachnida – Nervous system
Sensory Compound eyes – small but greater number Sensory setae – major sense organs
Mechanoreceptors 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
Order Scorpiones 3-21 cm in length Greatly enlarged
pedipalps Very small
chelicerae Stinger Predators – stay
near burrowhttp://www.regalreptile.com/scorpion%203.jpg
http://www.thedailylink.com/thespiralburrow/anatomy/anat02.html
Can sting within 0.75 sec.
Class Arachnida - Diversity
Order Scorpiones Gonochoric
Mature – 6 yrs Extended courtship
ritual Indirect sperm transfer
– spermatophores Viviparous Care of young Direct development –
months Live up to 25 yrs
http://www.regalreptile.com/scorpion%203.jpg
http://www.thedailylink.com/thespiralburrow/anatomy/anat02.html
http://cals.arizona.edu/pubs/insects/az1320/Female-bark-scorpionalt.jpg
Class Arachnida - Diversity
Order Uropygi Whip scorpions or
Vinegaroons 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
Order Uropygi 2 pair book lungs Pair of large
repugnatorial glands 84% acetic acid and 5%
caprylic acid 1st leg acts as
antennae Gonothropic
Complex courship Indirect sperm transfer -
spermatophore
http://www.petbugs.com/caresheets/gallery/M-giganteus.jpg
Class Arachnida – DiversityOrder Amblypygi
Whip spider 1st legs – antennae All legs sensory Anatomy similar to spiders:
Chelicerae similar to spiders but lack poison glands. repugnatorial glands
No silk produced Tends to move laterally Indirect sperm transfer -
spermatophore
http://www.amnh.org/exhibitions/hall_tour/spectrum/specimens/a2395h.jpg
Class Arachnida – DiversityOrder Araenae 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
Most Primitive Primitive chelicerae (only
longitudinal movement) Segmented abdomen
Primative Primitive chelicerae
Advanced Fangs can move to oppose each
other
Class Arachnida – DiversityOrder Araenae – Silk What is it?
Made of glycine, alanine and serine 6-8 different kinds
5-6 used by any one spider 0.003 mm thick
Produced by Silk glands – different kinds Spinnerets
Single thread composed of many fibers which are weaved together Cribellum – not in all
Anterior to spinnerets Fine silk used for prey capture
Spiders eat silk to reclaim it
Silk glands Spinnerets//www.astrographics.com/GalleryPrints/Display/GP2017.jpg
http://www.dmns.org/main/minisites/spiders/idkey1.html
Cribellum
http://www.dmns.org/main/minisites/spiders/idkey1.html
http://www.museums.org.za/bio/spiderweb/reproduction.htm
Class Arachnida – DiversityOrder Araenae – Silk Function
Reproduction Sperm web Egg case Nests
Dragline Dispersion Prey capture (webs)
http://typhoon.wcp.muohio.edu/tropicalvideos/costarica03/spidereggcase03.jpg
http://www.washington.edu/burkemuseum/spidermyth/images/draglinethumb.jpg
http://citybugs.tamu.edu/FastSheets/images/spider-ballooning.gif
Class Arachnida – DiversityOrder Araenae – Prey capture Web builders
Orbs Only the spiral is sticky Walk on radial Built to catch specific
types of insects Affected by food
Tunnel or Trapdoor
http://www.nancylynne.com/Spider%20Web%20for%20web.jpg
http://www.coffee.co.uk/spiders.html
http://www.1000plus.com/alex/ImageGallery/Arachnids%20-%20Spiders/tn/Tunnel%20Spider.jpg.html
Tarantula
http://mamba.bio.uci.edu/~pjbryant/biodiv/spiders/Aphonopelma%20reversum.htm
http://www.bushveld.co.za/pictures-arachnids/garden-spider-large.jpg
Hunting Heavier legs Good eyes in many
http://research.amnh.org/entomology/blackrock2/images/main_key/scopulae_philodromidae.gif
Class Arachnida – DiversityOrder Araenae – Prey capture
Scopulae – walk up walls or glass
http://www.dal.ca/~egingl/research.htm
Best developed slit sensors on legs- vibration
http://dine.sanjuan.k12.ut.us/heritage/land/animals/bugs/images/wolf_spider.jpg
Eyes Main Secondary
Class Arachnida – DiversityOrder Araenae – Prey capture
Fangs Movement http://www.geocities.com/spiders_snakes/spider/fang.jpg
http://static.howstuffworks.com/gif/spider-fang.gifhttp://www.museums.org.za/bio/spiderweb/bites.htm
Hunters – cytotoxin antibiotics usually required no anti-venom anti-tetanus injection Some patients
In 3 days mild fever, headaches
The above victim saw the Brown Recluse 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://www.brown-recluse.com/index.html?google1
Brown Recluse or Violin spider
Toxin
Class Arachnida – DiversityOrder Araenae – Prey capture
Fangs Movement
Web-builders – neurotoxin 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
Toxin
Black Widow
http://library.thinkquest.org/C007974/media/2_4bla.jpg
http://www.dobrodruh.cz/data/bookimg/00363-atrax.jpg
AtraxFunnel-Web spiderLETHAL
http://acd.ufrj.br/mndi/Aracnologia/Trechona.htm
TrachomaFunnel-Web SpiderLETHAL
Class Arachnida – DiversityOrder Araenae – Prey capture
Fangs Movement
Non-Toxic
http://www.ambergriscaye.com/pages/photos/art/tarantula.jpg
Class Arachnida – DiversityOrder Araenae – Digestion
Either totally dissolve prey with enzymes or masticate
Fluid sucked into midgut passing through particle filters
Digested in Caeca
Class Arachnida – DiversityOrder Araenae – Gas Exchange
Book lungs And/or tracheae
Class Arachnida – DiversityOrder Araenae – Reproduction
Gonochoric Indirect sperm
transfer No spermatophores Transferred by
pedipalps
Male spins sperm web (shown earlier)
Deposits sperm on web
Transfers sperm to pedipalps
Pedipalps transfer sperm to female
Class Arachnida – DiversityOrder Solifugae
Sun spider ~800 species 2 mm – 7 cm Inhabit warm arid regions Enormous chelicerae No venom 1st legs used as antennae Males extremely fast
Highly developed tracheae
http://www.key-net.net/users/swb/pet_arthropod/SS.jpg
Class Arachnida – DiversityOrder Opilones
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 May have 100s
Eyes on Tuberclehttp://www.thelensflare.com/large/spider_979.jpg
http://www.xs4all.nl/~ednieuw/Spiders/Info/spiderinfo.htm
Spider leg
http://troyb.com/photo/images/photos/00012918.jpg
Class Arachnida – DiversityOrder Acari
Ticks and mites ~40,000 described
>1,000,000 undescribed 0.1 – 0.75 mm length
Smallest can live in tracheae of honeybee
Present in all habitats tagmata different No segmentation Entire body covered with
single carapacehttp://www.uky.edu/Agriculture/Entomology/entfacts/struct/amdogtik.gif
Gnathosoma
Idiosoma
http://www.sdm.buffalo.edu/scic/toms_tick/tick-2_full.jpg
Pedipalp
Class Arachnida – DiversityOrder Acari
Large diversity in feeding Carnivores Herbivores Scavengers Ectoparasites Endoparasites
http://www.uky.edu/Agriculture/Entomology/entfacts/struct/amdogtik.gif
http://www.ijon.de/zecken/images/i-hex-wg.gif
Chelicera
Pedipalp
Class Arachnida – DiversityOrder Acari
Nervous system Sensory setae
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/
struct/amdogtik.gif
Class Arachnida – DiversityOrder Acari
Reproduction Gonochoric Indirect sperm transfer
by spermatophore Transferred by
chelicera, male 3rd pr. legs or female may pick up.
Eggs in soil or humus 2-6 wk incubation
http://www.uky.edu/Agriculture/Entomology/entfacts/struct/amdogtik.gif