Class Arachnida Flashcards

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Questions and Answers

How many pairs of legs do adults, nymphs, and larvae have in the class Arachnida?

Adults and nymphs have 4 pairs; larvae have 3 pairs.

What Subphylum would the Class Arachnida be under?

Chelicerata (Chelicerae)

What are some characteristics of the Order Scorpionida (Scorpions)?

Large pedipalps with pincers; elongated abdomen that curves over thorax with a spine and poison gland on tip.

What are some characteristics of the Order Araneida (Spiders)?

Cephalothorax joined to abdomen by a narrow waist; nymphs have 6 legs and adults have 8; chelicerae have poison glands. Signup and view all the answers

What are some characteristics of the Order Acarina (Mites and Ticks)?

Combined head, thorax, and abdomen into two sections; no antennae; simple eyes; mouthparts include palps, chelicera, and hypostome. Signup and view all the answers

What is the Suborder of Order Acarina?

Ioxida Signup and view all the answers

Of the three examples from Acarina (mites, hard ticks, soft ticks), which are microscopic and which are macroscopic? (Select all that apply)

Mites - microscopic Signup and view all the answers

What Family are Hard and Soft ticks associated with?

Har ticks are associated with Family Ixodidae; soft ticks with Family Aragasidae. Signup and view all the answers

In regards to position and visibility of mouth parts, what is known for mites, hard ticks, and soft ticks?

Mites and hard ticks have mouth parts dorsally visible; soft ticks have mouth parts not dorsally visible. Signup and view all the answers

In which of the three are scutums present (mites/hard/soft tick)?

Hard ticks have scutums present; mites and soft ticks do not. Signup and view all the answers

Which of the three have a basis capitulum and where is it located?

Mites have no basis capitulum; hard ticks have a dorsally visible basis capitulum; soft ticks have a ventral basis capitulum. Signup and view all the answers

What is the third tick Family and what is its significance?

Nuttalliellidae, only one species has been described (N. namaqua) but not extensively studied. Signup and view all the answers

What is the alternate classification of mite and tick orders based on?

Presence or absence and location of stigmata (respiratory opening). Signup and view all the answers

Study Notes

Class Arachnida Overview

Adults and nymphs possess 4 pairs of legs, whereas larvae have 3 pairs.
Classified under the Subphylum Chelicerata, characterized by chelicerae (mouthparts).

Order Scorpionida (Scorpions)

Notable for large pedipalps equipped with pincers.
Abdomen is elongated, curved over the thorax, with a spine and a poison gland at the tip.

Order Araneida (Spiders)

Cephalothorax connects to abdomen via a narrow waist.
Nymphs have 6 legs; adults have 8 legs.
Chelicerae contain poison glands; some species can envenomate humans and animals.

Order Acarina (Mites and Ticks)

Comprises arachnids of significant veterinary importance.
Body divided into two sections: anterior gnathosoma (capitulum) and posterior idiosoma (sac-like body).
Absent antennae, with mouthparts formed by palps, chelicerae, and hypostome.
Eyes, if present, are very simple.

Suborder of Acarina

Identified as Ioxida.

Microscopic vs. Macroscopic Acarina

Mites are microscopic.
Hard ticks and soft ticks are macroscopic.

Tick Families

Hard ticks belong to Family Ixodidae.
Soft ticks belong to Family Argasidae.

Mouthparts Positioning

For mites and hard ticks, mouthparts are dorsally visible.
Soft ticks have mouthparts that are not dorsally visible.

Scutum Presence in Ticks

Mites and soft ticks do not have a scutum.
Hard ticks feature a scutum, a shield structure on their back.

Basis Capitulum in Ticks

Mites lack a basis capitulum.
Hard ticks show a dorsally visible basis capitulum.
Soft ticks have a ventral basis capitulum.

Third Tick Family

Family Nuttalliellidae is noted for having only one described species (Nuttalliella namaqua), which is not extensively studied.

Alternate Classification Basis

Classification of mites and ticks relies on the presence or absence and the location of stigmata (respiratory openings, RSO).

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Description

Test your knowledge on the class Arachnida with these flashcards! Explore the number of leg pairs in different life stages, the subphylum classification, and specific characteristics of scorpions. Perfect for students and enthusiasts of arachnology.