Comparative Vertebrate AnatomyExercise 3. Exeternal Anatomy and Taxonomy of Vertebrates

I. Objectives:

For this exercise, the student shall:1) describe the external features of some representative vertebrate organisms2) distinguish major taxonomic classes of vertebrates based on their morphology

II. Methodology:

The student should refer to Chapter IV of the Hyman manual when examining various preserved specimens of selected vertebrates. These selected specimens includes the following:

1) shark/dogfish (male and female)2) teleost (any ray-finned bony fish)3) frog 4) lizard5) snake6) bird7) cat

Guidelines for illustrating the external anatomy of the listed specimens should follow those given in the introductory “GENERAL DIRECTIONS” in the Hyman Manual. Illustrations of observed specimens should be drawn in the boxes provided in the next section, with labels given outside the borders. As much as possible labeled parts should be descriptive. For example, the caudal fin of a lungfish should be labeled as “Diphycercal tail fin.”

Some structures not mentioned here, but included in the Hyman manual, may also be identified when applicable. Furthermore, the taxonomic labels (from Phylum to Genus) must be provided beside or beneath the drawing of each specimen.

III. Laboratory Output

1) Male and female Squalus specimens should be examined, and the following structures should be labeled in the lateral and/or ventral views of the animals: trunk and tail regions, rostrum, nostrils, spiracle and other gill slits, lateral line, upper and lower jaws, eyes, paired and median fins, caudal fin, claspers (in the male), cloacal aperture.

2) Examine any teleost (modern bony fish) from among the available specimens in the laboratory. Draw and label the following parts: trunk and tail regions, operculum, branchiostegal membrane, paired and median fins, eyes, nostrils, upper and lower jaws, caudal fin, dermal scales.

3. Observe a frog specimen (or a salamander if available). Draw and label the following pertinent parts: snout, external nares, eyes, tympanum, forelimb (with upper arm, forearm and manus) and hindlimb (with thigh, shank, pes), digits, cloaca.

Figure 1. Lateral and ventral (male) views of the external anatomy of Squalus.

Figure 2. External features of a teleost.

Lateral view Ventral view

Figure 3. External features of an amphibian specimen.

4) Observe a lizard and a snake as your reptilian representatives. For the drawing of each specimen, label the parts mentioned as in the amphibian specimen (refer to #3) as well as the following: epidermal scales, head shields, anal or ventral shields.

Figure 4a. External features of a lizard.

Figure 4b. Lateral and ventral views of a snake specimen.

Lateral view Ventral view

5) Observe a preserved specimen of any bird species from the laboratory collection. Draw your specimen and label the following parts: head, neck, trunk, uropygium, beak, external nares, rectrices, remiges (primaries, secondaries and teriatries), hindlimbs, digits.

Figure 5. External features of a bird specimen.

6) Examine a preserved specimen of a cat (or any mammalian carnivore). Make an illustration of the specimen from the lateral and caudal views. The following parts should be labeled: head, trunk, tail, vibrissae, nostrils, canines, claws, forelimb and hindlimb parts, external ears, eyes, mammaries (in females), inguinal space, anus, urogenital opening.

Figure 6. Lateral and caudal views of a preserved mammalian specimen.

Lateral view Caudal view