Echinoderm Paleobiology available in Hardcover
Echinoderm Paleobiology
- ISBN-10:
- 0253351286
- ISBN-13:
- 9780253351289
- Pub. Date:
- 07/18/2008
- Publisher:
- Indiana University Press
- ISBN-10:
- 0253351286
- ISBN-13:
- 9780253351289
- Pub. Date:
- 07/18/2008
- Publisher:
- Indiana University Press
Echinoderm Paleobiology
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Product Details
| ISBN-13: | 9780253351289 |
|---|---|
| Publisher: | Indiana University Press |
| Publication date: | 07/18/2008 |
| Series: | Life of the Past |
| Pages: | 472 |
| Product dimensions: | 7.10(w) x 10.20(h) x 1.30(d) |
| Age Range: | 18 Years |
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Echinoderm Paleobiology
By William I. Ausich, Gary D. Webster
Indiana University Press
Copyright © 2008 Indiana University PressAll rights reserved.
ISBN: 978-0-253-35128-9
CHAPTER 1
TAPHONOMY AS AN INDICATOR OF BEHAVIOR AMONG FOSSIL CRINOIDS
Tomasz K. Baumiller, Forest J. Gahn, Hans Hess, and Charles G. Messing
Introduction
Taphonomic processes lead to the loss of biological information as tissues degrade and skeletal elements become broken, abraded, and, ultimately, chemically modified. Information loss is not random but rather is a function of an organism's ecology, morphology, and behavior. Thus, taphonomists can use predictable patterns of preservation to ameliorate the negative effects of biotic degradation.
The multiplated skeletons of echinoderms are not particularly resistant to postmortem processes and disarticulate easily (Meyer and Meyer, 1986). Nevertheless, a sufficiently large number of specimens have escaped these taphonomic filters to leave a rich record of complete, or nearly complete, specimens (Brett and Baird, 1986; Meyer et al., 1989; Gahn and Baumiller, 2004). For benthic crinoid fossils, a high degree of articulation is typically associated with rapid burial and little transport (Simms, 1999a). Can the mode of preservation of well-articulated crinoids provide any insights into their behavior? Obviously, one way in which it can is if an organism is killed and buried instantly--what might be referred to as the Pompeii effect. In this instance, the organism might be preserved in a posture characterizing its normal behavior--that is, behavior under typical environmental conditions. However, even when rapid burial occurs, it is likely that the organism has had some time to respond to the rapidly changing conditions, and in that case, it might be buried in its trauma posture. Although the trauma response does not represent normal behavior, it nevertheless provides insights into the organism's functional abilities--or, perhaps, functional limits. The hypothesis we will test, therefore, is that the postures of well-preserved fossil crinoids should correspond to postures that characterized either their normal live behaviors or their trauma behaviors. We will do this by characterizing the normal and trauma behaviors, and by examining the mode of preservation in fossil comatulids and isocrinids. Finally, we will examine the mode of preservation of some stalked Paleozoic taxa and attempt to interpret their behaviors in light of these data.
Behavior and Taphonomy
COMATULID BEHAVIOR. Rapid burial events are attributable to large sediment loads and may be associated with increases in flow velocities; therefore, it is worth exploring the response of comatulids to such changing conditions. The most detailed in situ observations of comatulids to increasing fluid velocities have been made by Meyer and his collaborators (Meyer, 1973, 1997; Meyer and Macurda, 1980; Meyer et al., 1984). These observations revealed that comatulids generally respond to increasing flow rates either by modifying and sometimes deflecting their filter, or by crawling to find a protective crevice.
For comatulids experiencing high flow velocities, the arms become "compressed into a cylinder oriented downcurrent" (Meyer and Macurda, 1980, p. 79), and in this posture, the crinoid is reminiscent of a shaving brush (Seilacher, personal commun., 2003). Observations of comatulid postures during burial events have not been made in situ, but experiments with specimens tumbled in sediment-laden water, meant to simulate burial events, revealed that comatulids compress their arms tightly into a cylinder and maintain the shaving brush posture after hours of tumbling (Fig. 1.1; Baumiller, 2003).
In addition to the shaving brush response, deteriorating conditions, such as increasing current velocities or sediment load, might also induce comatulids to crawl. During crawling, comatulids maintain the "oral surface uppermost" (Clark, 1915, p. 13), with their arms arranged radially around the central disk. Clark noted that even when comatulids are dropped mouth down in the water column, or when placed mouth down on the bottom, they always righted themselves, resulting in the usual mouth-up orientation.
Given that the living position of comatulids and stalkless crinoids is generally mouth up and that under extreme conditions they may assume a shaving brush posture, it is reasonable to expect that those would be the postures of well-preserved fossil comatulids--that is, those with arms and calyx largely intact. Thus, the most common mode of preservation should be the shaving brush, with the arms compressed into a cylinder and the oral-aboral axis parallel to the substrate. Occasionally, the rapid burial of comatulids in normal living or crawling positions should lead to a mouth-up posture with the oral-aboral axis perpendicular to the substrate and the arms arranged radially around the disk--the starburst-up mode of preservation. The fact that the mouth-down behavior has not been observed in extant comatulids suggests that the starburst-down posture should be rare in this group.
COMATULID TAPHONOMY. As a test of the above prediction, we examined the orientation of the stalkless crinoid, Paracomatula Helvetica Hess, 1951, on several slabs from Hottwil, Switzerland (Klingnau Formation, Bajocian). None of the 42 specimens are preserved starburst down, but 11 are starburst up (Fig. 1.2); 23 are characterized by a shaving brush mode of preservation. An additional eight are either on their side or mouth up but neither starburst nor shaving brush; instead, their arms have an irregular arrangement neither radiating out nor compressed into a cylinder (Table 1.1).
The above observations confirm the predictions that mode of preservation is not independent of posture in live stalkless crinoids. Of course, this concept is not new; for example, Taylor (1983) reported that of several hundred specimens of Ailsacrinus abbreviatus Taylor, 1983, an essentially stemless Jurassic millericrinid, ~50% were preserved mouth up; this pattern was consistent with the usual living position of this crinoid and rapid in situ burial. Below, we apply the taphonomic approach to determine whether it can offer insights into the crawling abilities of stalked crinoids.
ISOCRINID BEHAVIOR. Knowledge of stalked crinoid behavior has grown greatly through the use of research submersibles. For instance, such research has shown that isocrinids predominantly live under low to moderate flow velocities (Breimer and Lane, 1978). In the normal feeding posture, the isocrinid stalk is subvertical with the proximal portion bent sharply downstream such that the oral-aboral axis of the crown orients parallel to the current direction with the oral surface directed downstream (Fig. 1.3.1). The extended arms are slightly recurved into the current, forming a concavo-convex filter, which has been named the parabolic filtration fan posture (Macurda and Meyer, 1974).
Isocrinids have also been observed under slack current conditions, where they maintain a so-called wilted flower posture with the arms flexed aborally, while the oral-aboral axis of the crinoid is vertical (Macurda and Meyer, 1974; Messing, 1985, Baumiller et al. 1991). Much less is known about their response to high current velocities, which make it difficult for submersibles to operate, and researchers have had limited opportunity to study deep-water crinoids under such conditions. However, available data allow us to generalize about isocrinids' response to high current velocities. The data consist of photos taken by a time-lapse camera deployed at 420 m for ~6 weeks' recording of isocrinids' responses to velocities ranging from less than 100 mm/s to well above 500 mm/s (Messing et al., personal commun.), and manipulation of isocrinids in situ with a submersible slurp gun (Fig. 1.4). In the latter case, a slurp gun was used in reverse to generate a high-velocity stream directed at the isocrinid Neocrinus decorus Wyville-Thomson, 1864, and its response was recorded with a video camera. Both the time-lapse photographs and the slurp gun video revealed that as current velocity was increased, the isocrinids changed their posture from the parabolic filtration fan posture to a shaving brush posture with the stalk and crown deflected downstream and the long axes of the arms aligned parallel to the current with their distal tips pointing downstream (Figs 1.3., 1.2, 1.4). More importantly, the slurp gun experiment revealed that the change in posture can occur rapidly, within seconds of the onset of high flow velocities. The isocrinid posture is similar to the high flow velocity posture described for comatulids by Meyer and Macurda (1980).
The above behaviors describe postures of isocrinids attached to the substrate by the distal end of their stalk with the crown elevated above the bottom. However, it is now an established fact that isocrinids are also capable of crawling. Direct evidence of isocrinid crawling became available through in situ observations (Messing et al., 1988) and laboratory flow-tank studies (Baumiller et al., 1991). These studies revealed that isocrinids could relocate by crawling with their arms and dragging the stalk along the substrate. Recently, data obtained from submersibles showed that they could move much faster (30–40 mm/s; Baumiller and Messing, 2005, personal commun.) than had been previously recognized (0.1 mm/s; Birenheide and Motokawa, 1994).
Two types of crawling behavior have been described: the slow mode (Baumiller et al., 1991; Birenheide and Motokawa, 1994) and the fast mode (Baumiller and Messing, 2005, personal commun.) mode. In the slow mode (Fig. 1.5.1), the stalk is dragged behind the crown along the bottom; its proximal portion is bent sharply such that the oral-aboral axis of the crown is subvertical; and the arms are arranged radially and are only slightly flexed aborally such that their long axes are roughly parallel to the substrate. This is analogous to the mouth-up crawling posture of comatulids. In the fast mode (Fig. 1.5.2), the stalk is also dragged behind the crown along the substrate, but the proximal portion remains nearly straight, so the stalk and the oral-aboral axis of the crown are horizontal. In this posture, only a portion of the strongly aborally flexed arms are in contact with the substrate; others face away from it. Finally, tumbling experiments with isocrinids have revealed that, just like comatulids, their posture when tumbled with sediment is the shaving brush, with the arms straight and compressed into a cylinder or a cone (Fig. 1.6; Baumiller, 2003).
ISOCRINID TAPHONOMY. The observed behaviors of isocrinids lead to predictions about their mode of preservation. The most probable burial posture of a stalked crinoid is the shaving brush, as it represents the behavioral response of the crinoid to high flow velocities and to tumbling with sediment (Figs 1.3.3, 1.6). Alternatively, burial during crawling would lead to a starburst-up mode of preservation (Fig. 1.5.1). To test these predictions, we examined the mode of preservation of the Jurassic isocrinid Chariocrinus andreae Desor, 1845, from several localities (Table 1.2). Although the shaving brush mode of preservation was most common (112 of 143 well-preserved specimens), 19 were starburst up (Fig. 1.7) and 12 were partially splayed on their side, but with the arms not compressed into a cylinder. No specimens of C. andreae were preserved mouth down; such a mode of preservation is expected to be rare, given that a mouth-down posture has not been observed among extant isocrinids. Chariocrinus andreae shares most morphological features with extant isocrinids, suggesting that it was capable of crawling; the preservation data seem to support its crawling abilities.
Implications for Other Stalked Crinoids
The comatulid and isocrinid examples confirm that the postures of well-preserved fossils are not independent of their mode of life or their trauma behaviors. We have demonstrated that well-preserved fossils of these taxa are most commonly represented by shaving brush postures, which indicate the trauma response. The starburst-up postures are also common. For comatulids, starburst-up postures may represent instantaneous burial in live position or while crawling, but for isocrinids, only the latter interpretation is feasible.
We have examined only a single isocrinid species for which starburst orientations can be determined, and we predict that for all isocrinids and other stalked crawlers, the shaving brush and starburst up postures would be the most common when preserved. On the other hand, stalked crinoids that were incapable of crawling generally should not be preserved starburst up because the mouth-up postures, such as the wilted flower posture, do not represent behaviors likely to be preserved. To test this prediction, we examined Paleozoic crinoids that lacked morphological characteristics of crawlers (Table 1.3)--that is, the well-developed muscular arm articulations that characterize post-Paleozoic articulates and Paleozoic advanced cladids (Simms and Sevastopulo, 1993; Simms, 1999b). Absence of muscles and especially of a fulcral ridge on the articular facet imply limited relative movement of brachials and arm flexibility, a major constraint on locomotion. Also, Paleozoic crinoids in our data lack those features associated with the ability to reattach to the substrate, a characteristic necessary for eleutherozoic life.
Examination of postures in our sample revealed that the shaving brush posture was the most common (Fig. 1.8), and the starburst-up posture was rare. Surprisingly, a starburst-down mode of preservation proved to be relatively common among these taxa, in contrast to its absence among comatulids and isocrinids (Fig. 1.9).
(Continues...)
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Table of Contents
IContentsIntroduction / William I. Ausich and Gary D. WebsterPart 1. Functional Morphology, Paleoecology, and TaphonomyIntroduction to Part 1 / William I. Ausich and Gary D. Webster1. Taphonomy as an Indicator of Behavior among Fossil Crinoids / Tomasz K. Baumiller, Forest J. Gahn, Hans Hess, and Charles G. Messing2. Attachment, Facies Distribution, and Life History Strategies in Crinoids from the Upper Ordovician of Kentucky / Carlton E. Brett, Bradley L. Deline, and Patrick I. McLaughlin3. Paleobiology of Carboniferous Microcrinoids / George D. Sevastopulo4. The Importance of Echinoids in Late Paleozoic Ecosystems / Chris L. Schneider5. New Observations on Taphonomy and Paleoecology of Uintacrinus socialis Grinnell (Crinoidea; Upper Cretaceous) / Andrew J. Webber, David L. Meyer, and Clare V. Milsom6. Taphonomy of the Irregular Echinoid Clypeaster humilis from the Red Sea: Implications for Taxonomic Resolution along Taphonomic Grades / James H. NebelsickPart 2. Evolutionary PaleoecologyIntroduction to Part 2 / William I. Ausich and Gary D. Webster7. Tiering History of Early Epifaunal Suspension-Feeding Echinoderms / Stephen Q. Dornbos8. Evolution and Extinction of a Paleozoic Crinoid Clade: Phylogenetics, Paleogeography, and Environmental Distribution of the Periechocrinids / William I. Ausich and Thomas W. KammerPart 3. Morphology for Refined Phylogenetic StudiesIntroduction to Part 3 / William I. Ausich and Gary D. Webster9. Paedomorphosis as an Adaptive Response in Pinnulate Cladid Crinoids from the Burlington Limestone (Mississippian, Osagean) of the Mississippi Valley / Thomas W. Kammer10. Cladid Crinoid Radial Facets, Brachials, and Arm Appendages: A Terminology Solution for Studies of Lineage, Classification, and Paleoenvironment / Gary D. Webster and Christopher G. Maples11. The Origin of Lovén's Law in Glyptocystitoid Rhombiferans and Its Bearing on the Plate Homology and Heterochronic Evolution of the Hemicosmitoid Peristomial Border / Colin D. SumrallPart 4. Mississippian Impacts and BiomakersIntroduction to Part 4 / William I. Ausich and Gary D. Webster12. Mixed-Age Echinoderms, Conodonts, and Other Fossils Used to Date a Meteorite Impact, and Implications for Missing Strata in the Type Osagean (Mississippian) in Missouri, USA / James F. Miller, Kevin R. Evans, William I. Ausich, Susan E. Bolyard, George H. Davis, Raymond L. Ethington, Charles W. Rovey II, Charles A. Sandberg, Thomas L. Thompson, and Johnny A. Waters13. Crinoid Biomarkers (Borden Group, Mississippian): Implications for Phylogeny / Christina E. O'Malley, William I. Ausich, and Yu-Ping ChinPart 5. Echinoderm Faunal StudiesIntroduction to Part 5 / William I. Ausich and Gary D. Webster14. Overview of Early Ordovician Crinoid Diversity from the Western and Southwestern United States / James Sprinkle, Thomas E. Guensburg, and Forest J. Gahn15. Ever since Ramsbottom: Silurian Crinoids of the British Isles since 1954 / Stephen K. Donovan, David N. Lewis, Rosanne E. Widdison, and Fiona E. Fearnhead16. Overview of Paleozoic Stemmed Echinoderms from China / Johnny A. Waters, Sara A. Marcus, Christopher G. Maples, N. Gary Lane, Hongfei Hou, Zhouting Liao, Jinxing Wang, and Lujun Liu17. Fossil Echinodermata from Puerto Rico / Jorge Vélez-Juarbe and Hernán SantosAppendicesIndexWhat People are Saying About This
Echinoderms have a rich fossil record that provides detailed information about evolutionary processes and the early development of marine ecosystems. This fine volume brings together fruitful new research approaches to the study of echinoderms, especially crinoids. It includes the work of editors/paleobiologists Ausich (Ohio State) and Webster (emer., Washington State), along with that of 42 other top contributors in the echinoderm field. Topics include taphonomy, functional morphology, paleoecology, morphology for refined phylogenetic studies, echinoderm-related evidence for impacts during the Mississippian period, crinoid biomarkers, and various faunal studies. These subjects are covered in 16 original research papers that present new data. In other words, this work is not a comprehensive overview of the biology and evolutionary history of echinoderms. Rather, it is a compilation of recent studies that apply the most current analytic techniques and interpretations to the scientific evidence provided by one very important phylum of organisms. The production values of the volume match the top quality of the research. The numerous black-and-white figures, maps, diagrams, and tables are printed at high resolution. This volume is useful for university libraries and essential for institutions with invertebrate paleobiology programs. Summing Up: Highly recommended. Upper-division undergraduate through professional collections. —Choice
Timely and necessary . . . the echinoderm fossil record provides the ideal data with which to ask important paleobiologic and evolutionary questions and to expect high—resolution answers.
"Timely and necessary... the echinoderm fossil record provides the ideal data with which to ask important paleobiologic and evolutionary questions and to expect high—resolution answers."
Echinoderms have a rich fossil record that provides detailed information about evolutionary processes and the early development of marine ecosystems. This fine volume brings together fruitful new research approaches to the study of echinoderms, especially crinoids. It includes the work of editors/paleobiologists Ausich (Ohio State) and Webster (emer., Washington State), along with that of 42 other top contributors in the echinoderm field. Topics include taphonomy, functional morphology, paleoecology, morphology for refined phylogenetic studies, echinoderm-related evidence for impacts during the Mississippian period, crinoid biomarkers, and various faunal studies. These subjects are covered in 16 original research papers that present new data. In other words, this work is not a comprehensive overview of the biology and evolutionary history of echinoderms. Rather, it is a compilation of recent studies that apply the most current analytic techniques and interpretations to the scientific evidence provided by one very important phylum of organisms. The production values of the volume match the top quality of the research. The numerous black-and-white figures, maps, diagrams, and tables are printed at high resolution. This volume is useful for university libraries and essential for institutions with invertebrate paleobiology programs. Summing Up: Highly recommended. Upper-division undergraduate through professional collections. —Choice