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November 12, 2011: THE FOSSIL RECORD: Fossil Guide

Instructor:Jonathan HendricksAssistant Professor of Paleontology, SJSU,

Dept. GeologyEmail: jonathan.hendricks@sjsu.edu

November 12, 2011: THE FOSSIL RECORD: Fossil Guide

Instructor:Jonathan HendricksAssistant Professor of Paleontology, SJSU,

Dept. GeologyEmail: jonathan.hendricks@sjsu.edu

Slide shows pictures of stromatolites.Slide shows pictures of stromatolites.

Oldest Fossils: StromatolitesOldest Fossils: StromatolitesOldest known fossil group: ~3.5

billion years old, Australia

Stromatolites: mat-like structures formed mostly by photosynthesizing bacteria called cyanobacteria.

Slimy layers + sediment. Oxygen by-product of

photosynthesis. Fossil Record: Archean

(become more abundant and diverse in Proterozoic) to Today

Mostly found today where grazing animals like snails cannot eat them.

Oldest known fossil group: ~3.5 billion years old, Australia

Stromatolites: mat-like structures formed mostly by photosynthesizing bacteria called cyanobacteria.

Slimy layers + sediment. Oxygen by-product of

photosynthesis. Fossil Record: Archean

(become more abundant and diverse in Proterozoic) to Today

Mostly found today where grazing animals like snails cannot eat them. By: “Rygel” (Creative Commons)

FusulinidsFusulinids Single-celled. Fossil Record:

Pennsylvanian to end-Permian.

Primary guide fossil for late Paleozoic.

Some very large (1-10 cm).

Make up the bulk of some late Paleozoic rocks.

Single-celled. Fossil Record:

Pennsylvanian to end-Permian.

Primary guide fossil for late Paleozoic.

Some very large (1-10 cm).

Make up the bulk of some late Paleozoic rocks.

Slide shows a photograph and drawing of fusulinids (images from the Kansas Geological Survey).

Slide shows a photograph and drawing of fusulinids (images from the Kansas Geological Survey).

QuickTime™ and a decompressor

are needed to see this picture.

"The source of this material is the Kansas Geological Survey website at http://www.kgs.ku.edu/. All Rights Reserved."

CoralsCorals

Corals belong in the Phylum Cnidaria, along with jellyfish and sea anemones.

Three major groups: Tabulate corals: Paleozoic Rugose corals: Paleozoic Scleractinian corals: Mesozoic and

Cenozoic

Corals belong in the Phylum Cnidaria, along with jellyfish and sea anemones.

Three major groups: Tabulate corals: Paleozoic Rugose corals: Paleozoic Scleractinian corals: Mesozoic and

Cenozoic

Tabulate CoralsTabulate Corals Skeleton calcitic. Exclusively colonial. Tightly packed, tubular coralites

(chambers of individual coral polyp); horizontal dividers along length of tube (tabulae).

Septa absent or short. Early Ordovician to Permian

(Paleozoic). 280 genera. Important Silurian and Devonian

reef-makers.

Skeleton calcitic. Exclusively colonial. Tightly packed, tubular coralites

(chambers of individual coral polyp); horizontal dividers along length of tube (tabulae).

Septa absent or short. Early Ordovician to Permian

(Paleozoic). 280 genera. Important Silurian and Devonian

reef-makers.

Slide shows a photograph of a tabulate corals.

Slide shows a photograph of a tabulate corals.

Rugose CoralsRugose Corals “Horn Corals” Skeleton calcitic. Some solitary, some

colonial. Middle Ordovician to

Permian (Paleozoic). Most diverse (800

genera) and abundant Paleozoic corals.

“Horn Corals” Skeleton calcitic. Some solitary, some

colonial. Middle Ordovician to

Permian (Paleozoic). Most diverse (800

genera) and abundant Paleozoic corals.

Slide shows two photos of horn coral fossils.Slide shows two photos of horn coral fossils.

The Work of John WellsThe Work of John Wells Devonian rugose corals. Show two types of growth

layers: thick and thin. Thick: annual/seasonal. Thin: day/night cycles. Wells counted number of

thin (daily) bands between thick (annual) bands.

Devonian corals: 400. Pennsylvanian: 387. What does this mean?

Devonian rugose corals. Show two types of growth

layers: thick and thin. Thick: annual/seasonal. Thin: day/night cycles. Wells counted number of

thin (daily) bands between thick (annual) bands.

Devonian corals: 400. Pennsylvanian: 387. What does this mean?

Slide shows a picture of a rugose coral fossil with many growth lines.

Slide shows a picture of a rugose coral fossil with many growth lines.

Scleractinian CoralsScleractinian Corals Skeleton aragonitic in

modern corals. Some solitary, some colonial. Six primary septa (divisions)

within coralites. Middle Triassic to Recent.

(Where are the Early Triassic corals??).

600 genera. Wide variety of forms. Major producers of reefs

since the Triassic.

Skeleton aragonitic in modern corals.

Some solitary, some colonial. Six primary septa (divisions)

within coralites. Middle Triassic to Recent.

(Where are the Early Triassic corals??).

600 genera. Wide variety of forms. Major producers of reefs

since the Triassic.

Slide shows a “close-up” view of a hexacoral.

Slide shows a “close-up” view of a hexacoral.

By: Jan Derk (Wikimedia Commons)

BrachiopodsBrachiopods “Lamp shells” Two calcitic

(typically) valves. Marine; sessile,

intertidal to abyssal.

Filter feeders (using lophophore).

Paleozoic: great diversity and abundance.

Today: cryptic and 120 genera.

“Lamp shells” Two calcitic

(typically) valves. Marine; sessile,

intertidal to abyssal.

Filter feeders (using lophophore).

Paleozoic: great diversity and abundance.

Today: cryptic and 120 genera.

Slide shows a photograph of a brachiopod shell.

Slide shows a photograph of a brachiopod shell.

MollusksMollusks Second most diverse

phylum (after arthropods): ~93,000 extant species. 70,000 fossil species.

Three major groups, all of which are known from the Paleozoic, Mesozoic, and Cenozoic eras:

Bivalves Gastropods Cephalopods

Second most diverse phylum (after arthropods): ~93,000 extant species. 70,000 fossil species.

Three major groups, all of which are known from the Paleozoic, Mesozoic, and Cenozoic eras:

Bivalves Gastropods Cephalopods

Slide shows a drawing of a gastropod shell by Ernst Haeckel.

Slide shows a drawing of a gastropod shell by Ernst Haeckel.

By Ernst Haeckel.

BivalvesBivalves Bivalvia = Pelecypoda Clams, oysters, cockles,

scallops, and mussels. Cambrian to Recent. 15,000 extant species,

40,000+ fossil species. Two valves (CaCO3). No head, few sense organs. Foot used for burrowing. Gills modified for respiration

and filter feeding. Mostly sessile, aquatic filter

feeders.

Bivalvia = Pelecypoda Clams, oysters, cockles,

scallops, and mussels. Cambrian to Recent. 15,000 extant species,

40,000+ fossil species. Two valves (CaCO3). No head, few sense organs. Foot used for burrowing. Gills modified for respiration

and filter feeding. Mostly sessile, aquatic filter

feeders.

Slides shows an illustration (by Ernst Haeckel) of a variety of bivalve shells.

Slides shows an illustration (by Ernst Haeckel) of a variety of bivalve shells.

By Ernst Haeckel.

Gastropods (Snails and Slugs)Gastropods (Snails and Slugs)

Most diverse mollusk group (~100,000 species).

Cambrian to Recent. Members occupy

many different habitats: marine (benthic and pelagic), freshwater, and terrestrial.

Most diverse mollusk group (~100,000 species).

Cambrian to Recent. Members occupy

many different habitats: marine (benthic and pelagic), freshwater, and terrestrial.

Slide shows an illustration of gastropod shells by Ernst Haeckel.

Slide shows an illustration of gastropod shells by Ernst Haeckel.

By Ernst Haeckel.

CephalopodsCephalopods 650 extant species; 17,000

extinct species. Late Cambrian to Recent. Subclasses: Coleoids (squids,

octopi, and cuttlefish), nautiloids, endoceratoids, and ammonoids.

650 extant species; 17,000 extinct species.

Late Cambrian to Recent. Subclasses: Coleoids (squids,

octopi, and cuttlefish), nautiloids, endoceratoids, and ammonoids.

Slide shows an illustration by Ernst Haeckel of various extant cephalopods and a photograph of a model of a modern nautilus.

Slide shows an illustration by Ernst Haeckel of various extant cephalopods and a photograph of a model of a modern nautilus.

AmmonoidsAmmonoids “Serpent Stones” “Horns of Ammon”

“Serpent Stones” “Horns of Ammon”

Slide shows various illustrations of ammonoids drawn by Ernst Haeckel.

Slide shows various illustrations of ammonoids drawn by Ernst Haeckel.

By Ernst Haeckel.

EchinodermsEchinoderms “Spiny skin”. Five-fold symmetry. Cambrian to Recent. Weird. All marine. Typically gregarious. Two subgroups with

great fossil records: Crinoids Echinoids

“Spiny skin”. Five-fold symmetry. Cambrian to Recent. Weird. All marine. Typically gregarious. Two subgroups with

great fossil records: Crinoids Echinoids

Slide shows photograph of a starfish.Slide shows photograph of a starfish.

JRH.

CrinoidsCrinoids “Sea lilies” Most of diversity extinct

(~700 extant species; 6000 extinct species).

Ordovician to Recent. “Starfish on a stick”: arms,

calyx, stem, root. Filter feeders; tube feet on

arms move food to mouth. Stem segments have

produced “crinoidal limestones”.

“Sea lilies” Most of diversity extinct

(~700 extant species; 6000 extinct species).

Ordovician to Recent. “Starfish on a stick”: arms,

calyx, stem, root. Filter feeders; tube feet on

arms move food to mouth. Stem segments have

produced “crinoidal limestones”.

Slide shows an illustration of various crinoids by Ernst Haeckel.

Slide shows an illustration of various crinoids by Ernst Haeckel.

By Ernst Haeckel.

EchinoidsEchinoids Echinoids; Sea urchins

and sand dollars. Late Ordovician to

Recent. Very good fossil record

(hard calcitic test; burrowing creatures).

Spines. Mostly herbivorous (eat

algae).

Echinoids; Sea urchins and sand dollars.

Late Ordovician to Recent.

Very good fossil record (hard calcitic test; burrowing creatures).

Spines. Mostly herbivorous (eat

algae).

Slide shows a photographs of a fossil echinoid.

Slide shows a photographs of a fossil echinoid.

TrilobitesTrilobites Arthropod phylum (bug-like animals). Cambrian (maximum diversity) to Permian (Paleozoic). About 1200 genera. Most important fossils for dating Cambrian rocks. Exoskeleton: mostly calcite; had to molt to grow. Cephalon (=head; facial sutures), thorax, pygidium

(=tail); thoraxes show trilobation.

Arthropod phylum (bug-like animals). Cambrian (maximum diversity) to Permian (Paleozoic). About 1200 genera. Most important fossils for dating Cambrian rocks. Exoskeleton: mostly calcite; had to molt to grow. Cephalon (=head; facial sutures), thorax, pygidium

(=tail); thoraxes show trilobation.

Slide shows an illustration of trilobites by Ernst Haeckel and a photograph of two trilobite fossils.

Slide shows an illustration of trilobites by Ernst Haeckel and a photograph of two trilobite fossils.

By Ernst Haeckel.

VertebratesVertebrates Animals with bones. Cambrian: first

vertebrates. Devonian: first tetrapods

(four-limbed vertebrates). Triassic: first mammals. Cretaceous: first

placental mammals. Paleogene: first modern

mammal groups. Pleistocene: first humans.

Animals with bones. Cambrian: first

vertebrates. Devonian: first tetrapods

(four-limbed vertebrates). Triassic: first mammals. Cretaceous: first

placental mammals. Paleogene: first modern

mammal groups. Pleistocene: first humans.

Slide shows a photograph of a fossil ground sloth skeleton.

Slide shows a photograph of a fossil ground sloth skeleton.