Arthropoda II -- Subphylum Chelicerata

Question 1

Chelicerata Characteristics (4)

Answer 1

Two Tagmata: Prosoma and Opisthosoma

# of Appendages: 
Prosoma = 6 appendages
Opisthosoma = variable # of appendages

1st Pair of appendages: Chelicerae (feeding)

2nd Pair of appendages: Pedipalps (diverse functions)

Question 2

3 Classes in Chelicerata

Answer 2

Merostomata - marine (horseshoe crab)
Arachnida - terrestrial (scorpions, spiders, ticks)
Pycnogonida - marine (sea spiders)

Question 3

Merostomata General Morphology

Answer 3

Prosoma
pedipalps look like the rest of the appendages
Pusher appendages, gnathobases at base of appendages
Opisthosoma
Genital operculum and gill opercula

Question 4

Arachnida Characteristics (6)

Answer 4

Terrestrial (exceptions)
Opisthosoma - few if any appendages 
Predators (exceptions)
Gas exchange - book lungs or tracheae
Excretion - malpighian tubules 
Reproduction - males transfer spermatophores (exceptions)

Question 5

Functions of Spider Silk (5)

Answer 5

Sperm transfer
Egg cases 
Prey capture
Aqualung - aquatic spiders 
Ballooning behaviour (juveniles)

Question 6

Scorpion Morphology

Answer 6

Pedipalps are large claws, with small chelicera for eating
Pectine - mechanosensory bristles on opisthosoma
Long telson with stinger

Question 7

Spider morphology

Answer 7

Chelicera with fang on the end
Pedipalps often look like front legs, only really used for sensory purposes
The pedicel is the constriction of the waist
Spinnerets on opisthosoma

Question 8

Mites and Ticks Morphology

Answer 8

Chelicera is used for making an incision into the host
Pedipalp used to support the head when taking blood
Hypostome drives into the wound to allow for blood-sucking

Question 9

Pycnogonida

Answer 9

Chelicera, proboscis, pedipalp, ovigerous leg, 4 pairs of walking legs on the prosoma
Small opisthosoma with anus on it

Question 10

Use of Ovigerous legs

Answer 10

Thes are used by males to brood the eggs and hold them