25. Hexapods & Myriapods Flashcards
Arthropods
Mandibles=
mouthparts derived from the coxa (basal article) of an ancestral limb
What are mandibles derived from?
the coxa (basal article) of an ancestral limb
Seta=
fine cuticular ‘hairs’ of arthropods
What are some functions of seta in arthropods?
Can be sensory, assist in locomotion (eg. swimming), protective covering, etc…
Insects and springtails belong to which superclass of Arthropoda?
Hexapoda
T/F
Almost all hexapods are marine
false
Almost all terrestrial
- many freshwater,
- very few marine
Superclass Hexapoda includes which important class that’s the most species-rich class of all Metazoa?
Class insecta
Give the 2 important classes of Hexapods
- Insecta
- Collembola (a class and an order!)
Describe the group ‘Entognatha’. What orders of Hexapods does this contain?
Collembola plus the two remaining orders of hexapods Protura & Diplura- don’t need to know) are usually put together in this group called ‘Entognatha’.
Sometimes Entognatha is considered a class
List the 5 morphological traits that are shared by all hexapods:
- only 1 pair on antennae
- single-articles mandibles
- tracheae and spiracles for gas exchange
- uniramous limbs
- 3 clear tagmata in adults (head, thorax, abdomen)
Why are Hexapoda named Hexapoda?
The thorax of hexapods has 3 pairs of jointed legs –> they’re 6-legged arthropods
(HEX= 6)
What does ‘Entognatha’ mean?
(root words)
“inside”= ento and “jaw”= gnath
Called this because their mandibles are enclosed by ‘cheeks’
Where did the name ‘springtail’ come from?
Collembola (springtail) have a forked terminal appendage called the furcula that is used for jumping/ springing
How do the internal mandibles of Entognatha articulate?
Internal mandibles articulate with the head capsule with only a single condyle (ball and socket joint)
Entognatha have a collophore. What is this and what’s it used for?
Collophore (a ventral tube)= a ventral projection that is used for water and ion regulation
It produces a sticky ‘glue’ substance that can stick them to the substrate
Collembola have simple single-lensed eyes. What are these called?
Ocelli
What makes Protura unique among Hexapods?
They completely lack antennae!
Are insects endognathous or ectognathous?
Ectognathous!
i.e. their mandibles are not enclosed in cheeks
T/F
Insects have compound eyes, not ocelli
False
Insects do have compound eyes, but often also have ocelli
