Trilobites Flashcards
trilobites range
cambrian - permian
trilobite PHYLUM
anthropoda
trilobites CLASS
trilobita
trilobites head
cephalon
trilobites middle
thorax
trilobites tail
pygidium
what is the exoskeleton of a trilobite made of
chitin
what were trilobite legs called
appendages
what was the free cheek of trilobites
part of the cephalon that breaks away from the skeleton during ecdysis
what is ECDYSIS
moulting/shedding skin
what were antenna in trilobites
to detect environment
what is glabella in a trilobite
part of cephalon (head) which may indicate diet
what iis a trilobite compound eye
an eye made up many calcite plates for vision
what is a trilobite facial suture
line of weakness along which the exoskeleton breaks away during ecdysis
what is the trilobite fixed cheek
part of cephalon(head) that stays attached to skeleton at the START of ecdysis
what is the trilobite pygdium
tali - may have spines
used to stabalise the animal
made of fused segments
what is the trilobite genal angle
part of cephalon (head) which may have spines attached
what is trilobite axis
central lobe running down the length of the trilobite extension
what were features of benthonic trilobite
many pleura - many legs for walking
crescent shaped eyes - can see above in all directions - lived on sea floor
large and not streamlined - did not swim
what is an example of a benthonic trilobite
calymene
define epifaunal
bottom dwelling - living on top of substrate or sediment
define infaunal
living in the sediment, burrowing
what were the features of planktonic trilobites
small - stay afloat in water
no/small eyes - animal did not hunt, either filter fed or ate organic rich sediment
inflated glabella - floatation mechanism
few pleura - few legs maybe paddle mechanism
what is plueron in a trilobite
a segment adjoining the axis
what is an example of a PLANKTONIC trilobite
Agnostus
what are the features of a NECKTONIC trilobite
eyes on stalk - can look all directions including below
inflated glabella - floation device
very small - floating
numerous separated pleura - many legs to swim - separate to aid buoyancy
what does PLANKTONIC mean
floating in the water column
what BENTHONIC mean
live on or in sediment or substrate
what does NECKTONIC mean
actively swimming in water column
what is an example of a NECKTONIC trilobite
deiphon
what are the features of BURROWING trilobite
no eyes (blind) - no hunting, food source organic rich sediment
wide cephalic fringe - spread mass on soft sediment/burrow
extended genal spines - spread mass, defence
pitted cephalic fringe - sensory hair holders in life to detect prey or water currents
example of BURROWING trilobite
trinucleus
