nautiloids and ammonoids Flashcards
nautiloid and ammonoid SUB CLASS
cephalopoda
cephalopoda SUB CLASS belongs to which PHYLUM?
mollusca
modern day examples of cephalopods
squid, cuttlefish and octopus
is nautilus alive now?
yes
are ammonites alive now
no
what is a protoconch
1st chamber occupied by juvenile
more chambers are added on as it grows
what is the septum
the wall which closes off the body chamber as the animal grows
what were the tentacles (nautiloid) for?
catching prey and movement
what is the septal neck
an extension of the septum protruding backwards towards the protoconch in nautilus
points away from protoconch in ammoites
what is the body chamber?
last and largest chamber housing most of the soft tissue
what are the 3 tpes of coiling?
involute
evolute
planispiral
what is involute coiling
inner coils are almost hidden by the last one
where can you see involute coiling
nautlilus
what is evolute coiling
earlier coils can be seen
wide umblilicus
where is evolute coiling common
ammonoids
what is plainspiral coiling
shell coiled in a single plane
what is the umbilicus
diameter of depression between the inside margins of the coil
what is AMMONOID morphology
evolute coiling
some have a keel (ridge along the middle for balance)
septal neck points away from protoconch
what is NAUTLOID mode of life
nektonic - lived in water column
what is the siphuncle
tube passing through septal neck which interconnects chambers
controls gas and water level to control BOUYANCY
NEKTONIC ammonoid/nautiloid (LATERAL MOEVEMNT) mode of life
lateral movement
tentavles used to swim in water column
jet propulsion where water is expelled from the ‘funnel’ to push ammonoid (usssually backward but can be aimed)
NECKTONIC ammonoid/nautilus (vertical)
empty chambers have mixture of gas and water
(gas is N rich)
levels adjust to make creature float upward/downward
HUNTER killer cephalopod
evidence suggests they were predators
spetal necks point towards or away from protoconch AMMONITE
away from protoconch
septal neck points towards or away from protoconch in NAUTILUS
towards protoconch
is siphuncle central in nautilus
yes
is siphuncle central in ammonoid
no, close to outer edge
simple to complex sutre lines
nautilus (simple)
gonatitic
ceratitic
amonitic (complex frilly)
which had v complex sutre line
ammonoid
which had simple sutre
nautilus
which was more complex sutre ceratitic or goniatitic
ceratitic
which was second most complex sutre
ceratitic
which was second most simple sutre
goniatitic
goniatite range
Devonian - permian
ceratite range
Triassic - jurassic
ammonite range
Jurassic - cretaceous
nautiloid range
Cambrian - present
how did they all evolve from nautilus
nautlius eveolved in Cambrian, evolved into goniatite -. ceratite and ammonite.
