Lecture 19

Question 1

internal phylogeny of arthropoda

Answer 1

until recently hexapods and myriapods considered sister taxa, recently hexapods nested within crustaceans

Question 2

pancrustacea

Answer 2

new crustacean clade to include hexapods

Question 3

3 arthropod tagmata

Answer 3

1. head (eating and sensing)
2. thorax (locomotion)
3. abdomen (digestion and reproduction)

Question 4

cephalothorax

Answer 4

head and thorax combined in some taxa

Question 5

trilobita

Answer 5

extinct in End-Permian (280 MYA), 4000, 1 pair antennae and compound eyes many pairs of biramous limbs

Question 6

biramous

Answer 6

2 branched

Question 7

“crustacea”

Answer 7

crabs, lobsters, shrimp, 50 000, most marine some freshwater/terrestrial

Question 8

crustacean morphology

Answer 8

1. 2 pairs antennae
2. biramous limbs
3. compound eyes (often on stalks)
4. cephalothorax, usually covered by carapace
5. mouthparts are mandibles
6. appendages guide food
7. thoracic limbs for locomotion
8. abdominal limbs for swimming, filter feeding, eggs
9. exoskeleton strengthened with calcium carbonate
10. exchange gases through gills (aquatic/semiterrestrial species) or tracheae (true terrestrial)

Question 9

carapace

Answer 9

shield that covers dorsal and lateral sides, sometimes also abdomen

Question 10

mandibles

Answer 10

single-segmented biting/chewing mouthparts

Question 11

crustacean reproduction

Answer 11

1. separate sexes (barnacles are hermaphrodites)
2. sperm transfer via copulation, intromission, or spermatophore deposited outside on female’s genital opening
3. females brood eggs until they hatch
4. most have larval stages, some direct development (freshwater/terrestrial) start out with 6-limbed nauplius larva

Question 12

copulation

Answer 12

male places sperm on or in the female’s sperm receiving structure

Question 13

crustacean feeding

Answer 13

filter feed, scavenge, prey on fish, commensals/parasites of vertebrates/invertebrates

Question 14

bottom-trawling

Answer 14

for prawns/shrimp, destroys benthic habitat, > 75% bycatch discarded

Question 15

hexapoda

Answer 15

insects and springtails, 6-legged, most terrestrial some freshwater few marine, important in pollination

Question 16

myriapoda

Answer 16

centipedes and millipedes, all terrestrial, oldest terrestrial fossils, direct development

Question 17

hexapods and myriapods 4 shared characteristics

Answer 17

1. 1 pair antennae
2. mandibles for mouthparts
3. tracheae (respiratory tubes) for gas exchange
4. uniramous limbs

Question 18

clade Mandibulata

Answer 18

pancrustaceans and myriapods, all have mandibles

Question 19

2 classes of hexapoda

Answer 19

1. Insecta (most diverse and species rich)

2. Collembola (springtails)

Question 20

hexapod morphology

Answer 20

1. 3 tagmata
2. entognathous (Collembola) or ectognathous (Insecta)
3. Collembola have forked terminal appendage used for jumping, collophore, and ocelli
4. Insecta have compound eyes and often ocelli, most have wings as adults (clade Pterygota) some apterygote

Question 21

3 hexapod tagmata

Answer 21

1. head (1 pair antennae)
2. thorax (3 pairs jointed legs)
3. abdomen (without paired jointed appendages)

Question 22

entognathous

Answer 22

mandibles enclosed by cheeks

Question 23

ectognathous

Answer 23

mandibles not enclosed

Question 24

collophore

Answer 24

ventral tube used for water and ion regulation in collembola, produces sticky substance

Question 25

ocelli

Answer 25

simple single-lensed eyes

Question 26

3 types of hexapod lifestyle

Answer 26

1. ametaboly
2. hemimetaboly
3. holometaboly

Question 27

ametaboly

Answer 27

primitively wingless groups, juveniles look exactly like small adults except have no genitalia

Question 28

hemimetaboly

Answer 28

wings develop slowly over several moults (as wing pads), juveniles may share morphology and habitat of
adult or different, juvenile often called a nymph

Question 29

holometaboly

Answer 29

wings develop all at once in a special stage

called a pupa, juvenile always has different morphology and ecology than adult, juvenile properly termed ‘larva

Question 30

hexapod reproduction

Answer 30

1. separate sexes

2. indirect sperm transfer in collembolans and apterygotes, pterygotes copulate

Question 31

indirect sperm transfer

Answer 31

spermatophore (encapsulated package of sperm) placed on a substrate

Question 32

entomology

Answer 32

main reason is economic importance of hexapods

Question 33

colony-collapse disorder

Answer 33

viewed as disaster, cause unclear

Question 34

myriapoda morphology

Answer 34

1. more than 3 pairs of legs

2. less tagmatized - head (ocelli, mandibles, 1 pair antennae) and trunk (9-325 pairs jointed legs)

Question 35

2 classes myriapoda

Answer 35

1. diplopoda (10 000)

2. chilopoda (2500)

Question 36

class diplopoda

Answer 36

millipedes, two pairs of legs and two stigmata per segment

Question 37

diplosegments

Answer 37

result of fusing of adjacent pairs of segments

Question 38

class chilopoda

Answer 38

centipedes, 1 pair of legs per segment, 1 pair of modified legs behind mouthparts, poison claws to subdue prey and fight predators

Question 39

chelicerata

Answer 39

horseshoe crabs, scorpions, spiders

Question 40

chelicerata morphology

Answer 40

1. lack antennae
2. chelicerae as main mouthparts
3. 2 tagmata - cephalothorax (carapace, 6 pairs limbs, eyes) abdomen (may or may not bear appendages, contains gut and reproductive organs)

Question 41

chelicerae

Answer 41

3 segmented pincer mouthparts, some species reduced to 2 segmented stabber

Question 42

6 pairs chelicerata limbs

Answer 42

chelicerae, pedipalps, 4 pairs legs

Question 43

2 classes chelicerata

Answer 43

1. xiphosura (4)

2. arachnida (90 000)

Question 44

class xiphosura

Answer 44

horseshoe crabs, marine, compound eyes, book gills, long terminal spine, ingest particles, planktonic larvae

Question 45

book gills

Answer 45

many flat plates look like pages of book

Question 46

class arachnida

Answer 46

spiders, mites, scorpions, most terrestrial few aquatic mites, ocelli, are fluid-feeding predators, separate sexes

Question 47

3 main orders arachnida

Answer 47

1. araneae (48 000)
2. scorpiones (1200)
3. acari (54 000)

Question 48

araneae

Answer 48

spiders, tight constriction between cephalothorax and abdomen, 2-segmented chelicerae, spinnerets, exchange gases through tracheae or book lungs, all fluid-feeding predators, poison glands empty through fangs of chelicerae, some use silk to capture prey, maternal care of eggs sometimes young

Question 49

spinnerets

Answer 49

abdominal appendages for spinning silk

Question 50

book lungs

Answer 50

look like book gills that have been enfolded by abdomen

Question 51

araneae sperm transfer

Answer 51

1. male deposits sperm blob on small web
2. sucks up sperm in modified pedipalp
3. inserts into female’s genital opening

Question 52

scorpiones

Answer 52

scorpions, desert or rainforest, pedipalps modified as grasping pincers, abdomen clearly segmented, terminates in poisonous sting

Question 53

acari

Answer 53

mites including ticks, do everything live everywhere, most fluid-feeders many detritivores ingest solid particles, young hatch with only 3 pairs of legs called larvae, most economically important arachnids,