Fossil Identification Lab

Earth Science Extras

by Russ Colson

 

For each of the fossils provided in picture and video form, identify the Phylum (and in some cases class and order) AND identify key characteristics of the fossil that is important in identifying that group.

 

Some major phyla of the animal kingdom are the following. I list a few of the subgroups (classes and orders) for some phyla.

Key characteristics of each group are included:

 

Sarcodina (single celled creatures that amoeba belongs to)

• Foraminifera (single celled creatures who make small shells called tests)

 

Porifera (the sponges) distinctive structures are often not preserved although spicules may be seen' The sponges might be spherical or tubular.

 

Cnidaria (including jellyfish and corals)

• Anthozoa: corals are mostly colonial creatures with septated individual holes

Scleractinia: modern corals, septated individual holes

Tabulate corals have layer-like tabulae,

Rugose corals are horn shaped and may not be colonial.

 

Bryozoa Colonial creatures, may be branching, encrusting, or fan-shaped, superficially resembling coral. Small holes where individuals lived but they are not septated.

 

Brachiopoda (sea-shell like creatures, modern ones are called lampshells) 2 shells, bilateral symmetry when view shell from top, opposing shells differ in size and/or shape--symmetry distinguishes from pelecypods.

 

Mollusca (including snails, clams, squids)

• Pelecypods: 2 shells, bilateral asymmetry when view shell from top although opposing shells are often mirror images
• Gastropods: single coiled shell with the shell often coiled out of a single plane in a spiral
• Cephalopods: shell coiled or straight, if coiled it is usually in a single plane, suture lines often seen if shell is peeled away

 

Arthropoda (includes insects, lobsters, spiders, and extinct trilobites) characteristics include exoskeleton, jointed appendages, segmented bodies, typically show bilateral symmetry).

 

Echinodermata (includes starfish and sand dollars) show radial symmetry, often pentameral

• Crinoidea: stalk made of small circular plates making distinctive "O's", sometimes find the calyx or 'head' made of small calcite platelets.

 

Hemichordata:

• Graptolites: Seaweed-like group of colonial creature, stipes are distinctive, usually occur as a carbon film

 

Chordata (include fish, amphibians, reptiles, mammals, and birds): look for bones or vertebrae

 

To aid in identification, example drawings from each of the phyla are provided here (In this file, the phylum is generally the heading centered above the pictures, the subphyla, class, and orders are listed under the phylum, usually with a colon, and the genus and species names are underneath the associated picture--take note that these may not be the same species that you are looking at, tlook for similar characteristics of their group)

Another source to aid identification, available as of this writing, mght be a cool digital atlas of fossils from the Paleontologial Insttute, found here.

These are true-to-life images that can be rotated and examined online. However, in some ways, drawings sometimes provide a better guide for identification than true-to-life images, because the drawings are an interpretation of what an expert saw in the fossils and can help bring out key features.

 

In the lab below, pictures of fossils, along with a short video (click on the camera to watch the video) of each fossil.

To identify, look for the key features in the list of fossil groups above and compare to the drawings of the fossils in the link above.

 

Fossil 1:

  

 

  

 

  

 

  

 

Be sure to watch the video for this one.

  

 

  

 

  

 Note: The fossil above comes from a group of creatures called nautiloid cephalopods--creatures a bit like squids in a shell. They first appeared during the Cambrian and continue until today, represented by the chambered nautilus.This particular fossil is from Ordovician rocks of Ohio. Like the chambered nautilus, this creature made a series of chambers in its shell, marked by the smoothly-curved suture line as seen in the fossil above. Fossils similar to this can be found in the Ordovician rocks of Southern Minnesota.

 

  

 

  

 

  

 

  

 

 

 

 

  

 

 

  

 

  

 

 

  

 

  

Be sure to check the video on this one.

  

 

  

 

  

 

 

Examine each of the rocks labeled 1A AND 5A below and compare them to the rock labeled as 10B. After careful analysis, answer the following questions:

 

 

 

Image 10B

 

Many of the fossils that you have examined throughout this lab come from Ordovician Age rocks that are located in the Cincinnati region of southern Ohio. It is thought that one of the major processes that concentrated fossils in the limestone beds were tropical storms. Which of the rocks (either 1A and 5A OR 10B) was deposited in the region closer to where the storm made landfall, and which one was in an area farther away from the storm? Look at the condition of the fossils and explain your answer, citing evidence .

 

 

 

last updated 7/22/2023.   Text, videos, and pictures are the property of Russ Colson.