Page 389 - Introduction to Paleobiology and The Fossil Record

376 INTRODUCTION TO PALEOBIOLOGY AND THE FOSSIL RECORD

Number of Number of Vanadium/(Vanadium+Nickel)
olenid specimens agnostid specimens ratio
0 5 10 15 20 25 30 35 0 5 10 15 20 25 30 35 40 (m)0.85 0.80 0.75 0.70
(cm)
230
Material collected by Lauridsen and Nielsen (2005) O. dentatus 200 Upper O. attenuatus Faulted cut in drill core (m)
220

210

190
180
170
160
–78.0
O. attenuatus
150
140
–78.2
130
120 Cyclotron sp. Lower O. attenuatus –78.1
No agnostic or –78.3
Olenus species
110
Material collected by Clarkson et al. (1998) O. transversus – O. truncatus – O. wahlenbergi 90 Range of O. truncatus –78.5
–78.4
100
Sole presence of
agnostids
80
70
–78.6
60
–78.7
50
to O. wahlenbergi
–78.8
40
30
20
–79.0
10 –78.9
O. transversus
0
Limestone –79.1
interval Limestone
not sampled O. gibbosus –79.2
Material collected by Lauridsen and Nielsen (2005) –30 Range of O. gibbosus –79.3

–40
–79.4
–50
Complete specimen Cephalon, Homagnostus
Cranidium, Olenus Pygidium, Homagnostus
Pygidium, Olenus Cephalon, Glyptagnostus
Loose cheek, Olenus Cyclotron sp. (bradoriid)
No data at this level

Figure 14.13 Microevolution and faunal dynamics of olenids in the Swedish Alum Shales. Olenus
species evolve gradually up through the section. (Based on Clarkson et al. 1998.)