Introduction to Chordates & Fish Anatomy - De Anza College

Fish Anatomy
This part of the lab comes to you straight from the grocery store. You’ll have the opportunity to
examine a variety of fresh fish.
Fish Taxonomy
The taxonomy of Chordates can be confusing, because there are traditional, well-known groups
(like fish) that don’t reflect real evolutionary relationships. Most fish have traditionally been
grouped in two classes within the phylum Chordata: Osteichtyes, or bony fish (which includes
most kinds of fish) and the Chondrichthyes, or cartilaginous fish (which includes sharks and
rays). However, the actual evolutionary relationships of fish are a bit more complex, as shown in
the cladograms in Campbell, ch. 34.
This lab will focus on the bony fish, traditionally classified as Osteichthyes. Most of the bony fish
belong to a group within the Osteichthyes called the Actinopterygii.
Fish Anatomy
In this handout, you’ll see various diagrams with numerous anatomical features listed. Study
them all, but the terms you’re likely to see on a lab exam are those listed in bold type in the text
of this handout. You won’t be tested on everything in the diagrams.
External anatomy
Before you cut the fish open, see what you can learn from the outside. Note that different fish
may have very different shapes, especially for their fins. Can you make any guesses about how
your fish lives
Look for the features shown in the diagram below.
Brian McCauley & Bruce Heyer 11/18/07 Page 6 of 13