Ecdysozoa (Arthropods) (Chapter 14)

Question 1

Superphylum Ecdyosozoa

Answer 1

arthropods
grow through molting (ecdysis)
noted for cephalothorax & abdomen
trilobites, scorpions, centipedes, insects, & crustaceans

Question 2

Phylum Arthropoda

Answer 2

monophyletic
ecdysis
extensions = legs
exoskeleton, cephalothorax & abdomen

Question 3

exoskeleton

Answer 3

organic material = chitin
may be of calcium carbonate or calcium phosphate shell
better potential for presevation

Question 4

cephalothorax

Answer 4

head - eyes, sensory organs (antenna), mouth, mandibles

thorax - legs w/ some level of blood ciruclation - locomotion, respiratory & circulatory activities

Question 5

abdomen

Answer 5

belly & digestive organs

Question 6

Subphylum Myriapoda (arthropod)

Answer 6

multiple legs
Ordovician/Silurian - Recent
poorly preserved
centipedes, millipedes - terrestrial

Question 7

Subphylum Tribitomorpha (arthropod)

Answer 7

3 lobed, cephalon, thorax, pygidium
trilobite - strictly marine 
Trilobites: Cambrian (dominant) - Permian (decline)
Trilobite-like: Precambrian?
good for biostratigraphy & paleoecology

Question 8

Subphylum Chelicerate (arthropod)

Answer 8

cephalothorax complex = prosoma - head + thorax: eyes, antenna, legs for swimming/crawling
opisthosoma:
tergite - segmented part, pre & post abdomen
telson - stingers/tail spine - out or in abdomen; typically long & spiny
merostomes: sea scorpions, scorpions, horshoe crab
arachnids: ticks & spiders - 6 pairs of appendages - motion & eating
fairly erratic fossil record
Cambrian? to Recent (except Eurypterids)
one of the 1st to conquer land

Question 9

Eurypterids = sea scorpion

Answer 9

subphylum Chelicerate
merostome
marine, inter-tidal (estuaries) 
fossil specimens & ichnofossils
Cambrian - Lower Paleozoic

Question 10

Subphylum Hexapoda (arthropod)

Answer 10

head, thorax, abdomen & 6 legs (adult form)
~90% of species diversity living invertebrates
majority small sized
dominant in terrestrial today - some fly; some marine; fairly common in freshwater - notably during larval stage
ants, beetles, dragonflies, flies, & wasps
Devonian - Recent
rare as fossils - mostly chitin shells
carbonization or amber preservation
symbiotic with angiosperm (flowering plants) during mid-Cretaceous = increase #’s insects as pollinators

Question 11

Subphylum Crustacea

Answer 11

cephalothorax complex
shell = calcium phosphate or calcium carbonate
marine; some freshwater; terrestrial - limited, still highly dependent on water)
crabs, lobsters; shrimps, barnacles, ostracods
Cambrian - Recent
Diversify rapidly during Cretaceous

Question 12

barnacles (Crustacea)
Subclass Cirripedia

Answer 12

secrets calcium carbonate outershell = house
some do not
swimming larval; attached to substrate as adult - parasitic

Question 13

ostracods (Crustacea)

Answer 13

sea fleas
important biostratigraphy & fossil record
extremely small
2 shelled = calcium carbonate typically 
water environment

Question 14

Decapoda

subtaxa of Crustacea

Answer 14

organisms w/ 10 limbs
crayfishes, crabs, lobsters, prawns, & shrimps
common from Mesozoic to Recent

Question 15

Subphylum Phyllocarids

Answer 15

shrimp with 2 shells