Arachnida

Question 1

Scorpiones

Answer 1

Body has long opisthosoma (telson) ending in a stinging apparatus.
Chelicerae are small, whilst the pedipalps (pincers) are large.
Sensory pectines (possible heat detectors) are attached centrally to the second adominal segment.
Has multiple book lungs and spiracles.

Question 2

Solpugida

Answer 2

Massive chelicerae, each consisting of a pair of articulating pieces.
Pedipalps are leg like and sticky at the end.
Four pairs of legs.
Very active with a well developed tracheal system.

Question 3

Opiliones

Answer 3

1-160mm spread, with legs.
No constriction between the prosoma and opisthosoma.
Chelicerae are small, pedipalps are short and leg like.
Legs are very long and slender.
Omnivorous
Trachea present for breathing.

Question 4

Acariformes

Answer 4

Abundant and widespread
Metamerisms lost (lack of body divisions)
Prosoma and abdomen are fused and the body is often covered in a single shield (carapace).
Chelicerae are housed in a beak (rostrum) which is also made up of pedipalps.
In Mites chelicerae are needle like for piercing, whilst in ticks chelicerae have hooks as well as a serrated hypostome.
Four pairs of legs
Trachea and opening (the spiracle)
Body of tick not sclerotized therefore is able to expand.

Question 5

Araneae

Answer 5

Produces silk (scleroprotein) from 6-8 spinnerets at the end of the opisthosoma.
Four pairs of legs
Males, the pedipalps are swollen at the end, which has been modified for sperm transfer, and is used in copulation.
Prosoma has a single carapace, usually with 8 eyes.
Single pair of book lungs and tube/sieve trachea.
Chelicerae equipped with poison glands.
Two parts of chelicerae
Malpighian tubules excrete guanine crystals.