Final Exam Invert

Panarthropoda - Echinodermata

What defines Panarthropoda?

Chitinous cuticle

What are lobopoda?

Unjointed walking legs that end in claws, ties panarthropods to arthropods.

Phylum Tardigrada

• Water bears

• Semi aquatic, marine, and freshwater

• Protrusible oral stylet to pierce plant material

• Thin cuticle that line the fore and hindgut

• Has a nervous system, large hemocoel, and lack motile cilia

• No gas exchange or circulatory features

• Osmoregulatory structure like Malpighian tubules

• 4 pairs of legs with adhesive glands

• Epidermis exhibits eutely

• Reproduction: Dieocious or parthenogenetic, internal fertilization, eggs shed in molt, resistant egg, direct development

• Cryptobiosis

Phylum Onychophora

• Terrestial

• Three pairs of head appendages (antennae, jaws, oral papillae)

• Many lobopodia

• Annulated appendages

• Reduced coelom

• Body surface covered by tubercles

• Gas exchange: Hemocoel for locomotion, tubular heart with ostia, hemal channels, trachae and spiracles)

• Feeding: Carnivore, slime gland, bite pray and inject saliva

• Reproduction: Diecious, internal fertilization, female may lay eggs or give live birth).

• Waste disposal: nephridia in each leg segment

• Sensory: ladder like nervous system, eye, sensory papillae

How are Onychophorans like Annelids?

• Muscular system

• Single pair of feeding appendange

• Non jointed appendages

• 1 pair of nephridia per segment

• Ocelli

How are Onychophorans like Arthropods?

• Striated jaw muscles

• Chitinous cuticle

• Hemocoel body cavity

• Spiracles and trachea

• Mandible like mouth parts

• Ostia in heart

• Legs extended via hydrostatic pressure

• Adhesive secretions

Defining characters of arthropods

• Jointed legs

• Calcified exoskeleton

• Muscle bands in antagonistic pairs

• No motile cilia

Arthropoda

• Bilateral symmetry

• Triploblastic protostomes

• Segmented body (head, thorax, abdomen)

• Well developed exoskeleton: Chitinous, calcified, allows muscle attachment, molters

• Compound eyes that allow UV and Polarized vision

• Reduced coelom and large hemocoel

• Open circulatory system with heart and ostia

• Three gut regions: foregut, midgut, and hindgut

• Nervous: dorsal cerebral ganglia, ventral nerve cord

• Striated muscle

• Excretion: Metanephridia and malpighian tubules

• Reproduction: Diecious and many methods of birth

Subphyla Trilobitomorpha

• Extinct

• Exclusively marine

• Oval bodies with 1 dorsal and 2 lateral lobes

• Body regions: Cephalon, thorax, pygidium

• Antennae and biramous appendanges

Subphyla Chelicerata

• Posses one pair of chelicera

• 2 body regions

• No antennae

• 1 pair of feeding chelicerae

• 1 pair pedipalps

• 4 pairs walking legs

Class Euchelicerata

• Subclass Merostomata

  • Prosoma covered by carapace

  • Pedipalps similar to walking legs

  • Book gills

  • Aquatic

  • Water scorpions

    • Order Xiphosura: Horseshoe crabs

      • 1 pair compound eyes, ocelli, chelicerae, pedipalps, 4 pair walking legs, unsegmented abdomen

      • Scavengaers

      • Sexual reproduction: diecious, female drags male to beach, female lay eggs in sand, male fertilize eggs, hatch in two weeks.

Subclass Arachnida

• All terrestrial

• Prosoma wholly or partially covered by carapace

• Opisthomal appendages absent

• Invaginated gas exchange (book lungs)

• Excretion: coxal gland, malpighian tubules

• Carnivores

• Eleven orders

Order Acari

• Mites and ticks

• Prosoma and opisthoma fused

• Mouthparts modified to form rostrum and buccal cone

• Parasitic and disease vectors

Order Scorpiones

• Scorpions

• Primitive

• Pedipalps have large pincers

• Telson is spine-like with poison gland

Order Pseudoscropiones

• Look like a scorpion with no tail

Order Uropygi

• Whip scorpions

• Large pedipalps and small chelicerae

• Two acidic liquid with tail

Order Solpugida

• Sun spiders

• Mostly desert habitat

• Large chelicerae

• Pedipalps long

Oder Opiliones

• Body regions into one region

• Repugnatorial glands: defensive and smell bad

• Scavengers

Order Araneae

• True spider

• Produce silk in spinnerets.

• Body segments joined by pedicel

• Book lungs

• Chelicerae have fang and poison gland

• Male pedipalps modified for copulation

Class Pycnogonida

• Thick knobby knees

• All marine

• Intertidal to deep sea

• Anterior proboscis

• Ovigers

• Predators

• Reproduction: dioecious, embryos brooded, protonymphon larvae