INVERTEBRATE PALEONTOLOGY

3rd EXAM 1999

 

I. Identification: What term is defined or described by each of the following statements? (20)

 
1. Uniramous, pre-oral appendages found in almost all arthropods; nerves for these appendages arise from the deutocerebrum. __________________________

2. Marginal area of ventral calcification on the sclerites of a trilobite. ________________________________

3. Cord of living tissue that runs through the phragmocone of cephalopods. __________________________________

4. Rasping structure in the mouth of molluscs that bears numerous small teeth which in some species are composed of magnetite. _____________________________

5. Small structure unique to the rostroconchs that served to hold the two halves of the shell together. _________________________________

6. Compressional ligament found inside the hinge in some pelecypods that aids in valve opening. ___________________________

7. Biostratigraphically speaking, a fossil taxon that has a short stratigraphic range, a wide geographic range and is relatively easy to find; particularly useful in making intercontinental correlations. __________________________________________________________

8. That part of the shell or conch of a cephalopod that is divided by septa; the part behind the living chamber. _______________________________

9. Lines of weakness in the exoskeleton of arthropods that facilitate molting. __________________________________

 

10. The property of features found in different taxa that can be said to be derived from the same structure in the common ancestor of those taxa. ________________________

 

II.Functional morphology: For each of the following features, identify the group in which it occurs and tell what its function is. (15)

 

1. vincular notches

 

2. gnathobases

 

3. articulating half ring

 

4. hyponome

 

5. byssus

 

III. Answer only 55 points worth of the following questions. Use diagrams or drawings as necessary or useful.

 

1. What are the two types of eye structure found in trilobites? Name and describe them. Discuss the differences in structure and taxonomic distribution. (10)

 

2. Describe three analytical approaches to interpreting the life habits of fossil organisms (functional analysis), and indicate the relative reliability of each. (15)

 

3. Name and diagram the different suture patterns found in ammonoid cephalopods. Indicate in your diagrams: the venter, adapertural direction, lobes and saddles. (15)

 

4. Describe the various feeding strategies found in the major groups of molluscs. What type of food is consumed, how is it obtained and what specialized organs are used in the process? (20)

 

5. Describe the valve opening and closing mechanism in pelecypods. Include all soft tissue and skeletal structures involved. (10)

 

6. What are the three major types of biozone that may be recognized? Briefly describe each and indicate their relative utility for correlation. (15)
7. What is enrollment in trilobites, and how are some trilobites adapted to facilitate this behavior? (5)

8. What is the HAM for mollusks? What features are present in it? (10)

9. What is the fundamental principle of biostratigraphy? (5)
 
 

IV. Select one of the following sets of taxa and construct an hypothesis of phylogenetic relationships among them in the form of a cladogram. Provide appropriate evidence for each grouping by indicating derived characters. (10)

 

Balanus (barnacle)

 

Limulus

Peripatus

lobster

Eurypterus

Scleractinia

earthworm

 

oyster

mesogastropod

abalone

Pecten

Ptychagnostus

Phacops

 

brachiopod