This is an open book test. You may use notes and text book. Maximum points possible: 100.

There are 3 parts of the lab test. Part 1 consists of 5 questions on fossils; there are 5 sets of fossils. Part 2 consists of 20 short questions on fossils; there is only one set. Part 3 are theoretical questions, no material required.

Question 1: There are 3 brachiopods and 3 bivalves in this box. Give a concise description (may include drawing) of each, including information on mode of preservation, and whether it is a bivalve or a brachiopod. Give your reasons. Compare numbers 314 and C264 (one of which is a brachiopod, one a bivalve) and speculate on the mode of life of each. 8 points.

1. C157: Rhynchonellid brachiopod; complete hard parts; original or recrystallized; has straight hingeline, biconvex, coarsely ribbed, sulcus, plane of symmetry through valves. No-small pedicle foramen.
2. C264: Productid brachiopod, complete hard parts, original or recrystallized; straight hingeline; planoconvex to concavoconvex; spine bases; plane of symmetry through valves. No-small pedicle foramen.
3. 751: Strophomenid brachiopod, complete hard parts, original or recrystallized; finely ribbed, very flat concavoconvex, plave of symmetry through valves. No-small pedicle foramen.
4. 314: Bivalve Arca: straight hingeline, one shell available only, has no plane of symmetry through shell; original; taxodont; two muscle scars, no palliate sinus.
5. B614/464: Bivalve Gryphaea, one valve only; in most specimens one muscle scar can be seen; dysodont dentition like other oysters; no plane of symmetry through shell.
6. 326 (or 54 or 625): Bivalve; shells dissolved, only sediment infill available; plane of symmetry between shells.

Productid brachiopod: live close to sediment surface, supported by spines to prevent sinking in soft sediment; passive filter feeders. Arca bivalve: most live attached to rocks, hard substrate; filter feeders (active; pump water over gills).

Question 2: Describe the important features of this bivalve, and speculate on its mode of life. 4 points.

Only one valve available. Heterodont dentition (few large teeth), 2 muscle scars, pallial sinus. This clam had a fairly short sipho (pallial sinus), lived buried shallowly in sediment, filter feeding.

Question 3: There are 5 prosobranch gastropods in this box (N= Natica, T= Turritella, C=Cypraea, P=Pleuroplaca, Cr= Crepidula). Describe each concisely (may include drawing), and determine whether each is most probably an Archeogastropod, Mesogastropod or Neogastropod; describe characters that make you decide to which group the gastropods belong. Speculate on mode of life for each. 8 points.

1. Natica: mesogastropod, large, round opening, no siphonal canal; probably predator, moon shell (see text book figure)
2. Turritellla: mesogastropod; shell can burrow efficiently, but some turritellids are unusual snails, living by filter feeding (text book figure); predator counted as correct
3. Cypraea (or cowrie): mesogastropod, mantle covers outside of shells; burrow efficiently; predator )text book)
4. Pleuroplaca: long siphonal canal; probably neogastropod; predator.
5. Crepidula (or limpet): mesogastropod, algal grazer on rocks.

Question 4: This is an echinoderm fossil. To which group of Echinodermata does it belong? During which period of earth history did/does this group exist? What features can you see in this fossil? Can you speculate on its way of life, specifically what it ate and how it obtained its food? 4 points.

This is a crinoid, most common during the Paleozoic (after the Cambrian), with a few surviving relatives. Fairly large calyx (with tubercles), individual plates not visible; thin arms, branched multiple times just above the calyx, and then further non-branched; many thin pinnules present, passive filter feeder, specializing in small food particles, possibly long-stemmed because of presence of pinnules, branched arms (but calyx is a bit large).

Question 5: To which Phylum and group does this fossil belong? Which characters can you use to determine that? How did this organism live? About when was it alive? 6 points.

This is a part of a straight ammonite, as clear by the presence of strongly convoluted septa. Straight ammonites probably lived floating in the water column, most common during the later part of the Cretaceous.

• 6A: To which two Phyla do these organisms belong? To which groups within the Phyla? Barnacles (Crustacea, Arthropoda) on Pecten (Bivalvia, Mollusca).
• 6B: To what Phylum does this organism belong? How did/does it live? Sponge (Porifera); lives by pumping water through its body, picking up food particles.
• 6C: What type of gastropod is this? What was its mode of life, most probably? Neogastropod (long siphonal canal); probably predator.
• 6D: What part of a trilobite is preserved? What type of trilobite was it, and when did it live? Part of the cephalon; one eye is clearly schizochroal, making this a phacopid trilobite, most common in Devonian.
• 6E: What type of organism is this fossil? It has not been in a lab test, but you have seen it in class. Receptaculitis, see figure 19.5 in text book, colonial chlorophyte algae. I gave 2 points if your guess could have been right, e.g., bryozoan. People who got it right got an extra credit point.
• 6F: Is this fossil a bivalve or a brachiopod? On which character(s) do you base this opinion? This is a Gryphaea (oyster), bivalve, as seen in the lab class. Only one shell available, has no plane of symmetry through it. One muscle scar barely visible; dysodont hinge. No pedicle opening, no remains of brachidium.
• 6G: To which group of vertebrates does this skull belong? How do you know? What type of cranial fenestration does it have? This is a mammalian skull (related to forms in box 4.1 textbook); its teeth are heterodont, with synapsid fenestration. These were actually (fairly primitive) plant eaters, although they had large canines. The teeth formula indicates they were placentals, not marsupials.
• 6H: To which Phylum and groups of organisms does this specimen belong? Hint: this is one of two valves. This is an inarticulate brachiopod (one of two valves, no hinge); absence of hinge combined with hint that it has 2 valves means it can only be an Inarticulate brachiopod. No trace of any hinge!
• 6I: To which Phylum and group does this organism belong? Which part of the organism's skeleton is it? This is the calyx of a crinoid (Echinodermata); note plates in the cup, ring of 5 around place of attachment of the stem; other plates visible' tegmen present.
• 6J: This box contains two fossils (A and B). What are they, and how can you see that? Both are cephalopod molluscs, A is a nautiloid with simple, slightly curved septa, B an ammonite with the convoluted septa.
• 6K: Is this fossil a bivalve or a brachiopod? On which character(s) do you base this opinion? This is a bivalve; clearly visible is the dysodont hinge with the organic ligament (chondrophore); one muscle scar. In this bivalve the shells are not symmetric! Lack of pedicle foramen, nature of hinge and clear muscle scar show it is a bivalve.
• 6L: this is a plaster cast of a skull. What type of cranial fenestration do you think it has? What is it? Diapsid, a crocodile.
• 6M: To which Phylum and group within the Phylum does this fossil belong? Why do you think so? Can you guess during which period of Earth history it lived? This is a gastropod (Mollusca); no sign of septa. It is a species of Paleozoic snail (Maclurites , see figure in text book). Note that the spiral is trochospiral, yet another pointer it probably as a snail.
• 6N: Rock: describe at least 3 Phyla present in this rock. What is the probable age of this rock? Phyla present: Bryozoa, Corals, Echinodermata (crinoid stems), Brachiopoda (rare). Paleozoic.
• 6O: What parts of a trilobite do you see preserved? To what type of trilobite did they belong? Mode of life? What can you say about the environment of deposition? There is a cephalon and a pygidium. The cephalon shows it is part of a Trinucleid trilobite; blind, small. May have lived as filter feeder; black sediment indicates low oxygen conditions.
• 6P: to which Phylum does the most common fossil in this rock belong? How do you know? What is its type of preservation? A Spriferid brachiopod; most are molds; recrystallization clear in one specimen in which the brachidium is preserved; part of original material present (in nrachidium).
• 6Q: This is a scale model of a microfossil; real size about 250 mm long. What is the organism? What type of shell does it have? It is a model of a benthic foraminifer with a triserial test.
• 6R: To which Phylum and group does this fossil belong? Why do you think so? It is a Mollusc, piece of an ammonite. The convoluted septa are clearly visible.
• 6S: To which Phylum and group within the Phylum does this organism belong? This is a snail (Abalone, Mollusca). Shell does not have a hinge; overall shape is very quickly widening spiral, not one of two valves.
• 6T: you have not seen this fossil in any of your lab classes. To which Phylum does it belong? Why do you think this? It must be an arthropod (segmentation); it is in fact a Eurypterid (figure 14.10 in textbook).

Theoretical questions, 1 point each (total 10 points):

1. What feature will help you determine whether a trilobite was a juvenile or an adult? Number of segments.
2. Which feature(s) would you use to distinguish a sponge from a coral? Radial symmetry in corals, none in sponges.
3. Salt marsh benthic foraminiferal faunas are dominated by species with which type of test? Agglutinated tests.
4. Do sea urchin tests show accretional or additional growth? Both.
5. Of brachiopods and bivalves, which has in general the highest metabolic rates? Bivalves; they are active filter feeders as compared to passive filter feeding brachiopods.
6. In one set of samples (A), the difference in carbon isotope ratios measured in planktonic and benthic foraminifera is much larger than in another set of samples (B). Which set of samples would represent a region with higher surface productivity? A (if you said you had to know whether plankton or benthic values was higher you were correct)
7. Are growth patterns of regular ammonites allometric or isometric? Allometric (logarithmic curve, not linear growth function)
8. Which shell feature do you use to determine whether a gastropod had a long sipho? Which feature would you use in a bivalve? Presence of siphonal canal in gastropod; presence of deep pallial sinus in bivalve.
9. If the oxygen isotope value of a deep-sea benthic foraminifer is -0.5 ^o/_oo, what would the water temperature be if there were polar ice caps of about the same size as today? Is the assumption of large polar ice caps realistic? You would get a temperature of about 18^oC for deep ocean waters (see below), assuming average values for present day sea water of -0.28 ^o/_oo. Since that reflects temperatures at the poles, this is not very probable: at such high temperatures ice caps would not be stable:

   t = 16.9 - 4.38 [-0.5+0.28] + 0.1 [-0.5+0.28] = 16.9 + 0.96 + 0.005 = 17.87 ^oC.

10. Which feature(s) do we use in order to guess whether a crinoid had a long stem or not? Size of calyx, presence of fine pinnules, branched arms