BAESIBAESI November 12, 2011: THE FOSSIL RECORD: Fossil Guide Instructor:  Jonathan Hendricks  Assistant Professor of Paleontology, SJSU, Dept. Geology  November 12, 2011: THE FOSSIL RECORD: Fossil Guide Instructor:  Jonathan Hendricks  Assistant Professor of Paleontology, SJSU, Dept. Geology 

Slide shows pictures of stromatolites. Oldest Fossils: Stromatolites 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)

Fusulinids  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). "The source of this material is the Kansas Geological Survey website at All Rights Reserved."

Corals 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 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.

Rugose 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.

The 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.

Scleractinian 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. By: Jan Derk (Wikimedia Commons)

Brachiopods  “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.

Mollusks  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. By Ernst Haeckel.

Bivalves  Bivalvia = Pelecypoda  Clams, oysters, cockles, scallops, and mussels.  Cambrian to Recent.  15,000 extant species, 40,000+ fossil species.  Two valves (CaCO 3 ).  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 (CaCO 3 ).  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. By Ernst Haeckel.

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. By Ernst Haeckel.

Cephalopods  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.

Ammonoids  “Serpent Stones”  “Horns of Ammon”  “Serpent Stones”  “Horns of Ammon” Slide shows various illustrations of ammonoids drawn by Ernst Haeckel. By Ernst Haeckel.

Echinoderms  “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. JRH.

Crinoids  “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. By Ernst Haeckel.

Echinoids  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.

Trilobites  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. By Ernst Haeckel.

Vertebrates  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.