A bivalve that evolves during and goes extinct during the Cretaceous.
In __________, the bottom vavle elongates into a cone shape and the upper valve becomes flat and lid-like.
Ammonites (Class __________) go extinct at the end of the Cretaceous.
__________ (Class Cephalopoda) are relative of modern squids and octopi; they do not have an external shell.
They do not have an external shell like ammonites, they have an internal calcite cone (phargmocone) that is often preserved.
Geologic Range of Ammonitic Suture Pattern.
Late Plaeozoic and Early Mesozoic
Geologic Range of Cerititic Suture Pattern.
Geologic Range of Goniatitic Suture Pattern.
Cambrian to Recent
Geologic Range of Nautoloid Suture Pattern.
Ammonites during the Mesozoic come in coiled and straighter forms such as __________.
Ammonites during the Mesozoic come in coiled and __________ such as Baculites.
Phylum __________ - phylum contains Ammonites, Gastropods, and Clams (Bivalves).
Clams - Class __________
clams and pectins
_____ and _____ have bilateral (2-sided) symmetry between the top and bottom shells.
oysters and rudist
_____ and _____ do not have bilateral symmetry between top and bottom shells.
__________ tend to be "comma" shaped.
__________ have 2 muscle scars.
oysters and pectins
1 muscle scar for _____ and _____.
Ammonites/Nautiloids/Belemnites - Class __________
Gastropods (Snails) - __________
__________ do not have sutures or septa walls. They are open all the way up through the shell.
steinkerns or internal molds
Because gastropods shells are aragonite which is unstable, _______ or _______ are common preservation forms for gastropods.
Dinosaur Bone, preservation - usually __________ - mineral fill between bone cells, bone cell visible, but can be replacement if no bone cells visable.
Egg Shell, preservation - __________
permineralization or replacement
Coprolites, preservation - can be __________ or __________.
Many of the fossils around Austin are oysters or their relatives. One of the most common oysters in our area is the small Texas toenail or __________.
top and bottom
Clams can be identified from brachiopods by their symmetry, most clams have _____ and _____ symmetry of valves but are NOT bilaterally symmertical from left to right. Note the modern clam; it has 2 muscle scars inside its shell.
__________ symmetry is opposite to bivalves, Top to Bottom shell not symmetrical but right to left side of one shell symmetrical.
Pectins(_______) almost have right/left bilateral symmetry as well as top and bottom symmetry. Note; the oysters do not have top/bottom symmetry, in the Cretaceous this is also true of the rudists clams.
__________ are stones that herbivore dinosaurs swallowed to aid in the grinding-up or maceration of the plant material they eat.
plant, digestive acid
Over time these stone become smooth and polished due to the constant rubbing against the __________ material and the __________ in the gizzard area of the stomache.
The fossil preservation in bone is often __________, the original cell materail is still present but the interior of individual cells as been filled in with minerals such as silica or calcite.
Deposition in pore spaces of buried remains by underground solutions of mineral material, most commonly calcium carbonate, silica, pyrite, or dolomite, which are unlike original shell or bone composition.
Conversion into a more stable form (such as the calcite form of calcium carbonate) of less stable compounds (such as aragonite form of calcium carbonate of some clams and snails).
Complete dissolution and replacement (or nearly so) by new mineral material of original material ( such as shells or bones).
Toothed mouth and feeding structure in some mollusks, such as gastropods.
What are the number of species of mollusks know living today.
some type of foot
What do all mollusks have?
stronger shells and spikes on their shells
How have mollusks evolved to protect themselves in the past?
Gary Vermeij uses the analogy that repaired breaks in millusks shells are equivalent to what?
muscular foot, swimming ability, foil ridges so crabs cannot grip
What are some of the strategies modern mollusks have used to survive?
Removal by dissolution of organic material buried in sediment; void left in the rock is a mold (for example, an imprint).
Molds can be __________ (expressing the shape of the inside of a shell or other feature).
Molds can be __________ (expressing the outside of the object).
Filling of a mold (void) with sediment or mineral material, thus preserving the shape (internal or external) of the organic feature.
__________ are preserved fecal material (dung, poo, doo-doo, ect.). They are considered trace fossils.
The fossil preservation of Mesozoic coprolites is often __________ but __________ is also common.
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