CHAPTER TWENTY-ONE J. Michael Moldowan, Stephen R. Jacobson, Jeremy Dahl, Adnan Al-Hajji, Bradley J. Huizinga, and Frederick J. Fago Molecular Fossils Demonstrate Precambrian Origin of Dinoflagellates The natural product chemistry of modern organisms shows that dinosterols are concentrated in, and are nearly exclusive to, dinoflagellates. Saturated dinosteroid (dinosteranes) and triaromatic dinosteroid hydrocarbons found in rock extracts and petroleum are molecular fossils of dinosterols. We observed a virtually continuous dinosterane record in Precambrian to Cenozoic organic-rich marine rocks. Ratios of dinosterane concentrations to those of steranes with affinities to other taxa are un- even, with relatively high ratios in some Vendian to Devonian extracts, low ratios in Carboniferous to Permian extracts, and high ratios in Upper Triassic through Creta- ceous extracts. A similar record was found for triaromatic dinosteroids, which were absent (undetected) in the Carboniferous to Permian extracts. These results show a parallel trend between fossil dinosteroids and the combined cyst records of acritarchs and dinoflagellates. This record reflects the high abundance and diversity of Cam- brian to Devonian acritarchs, the relatively low abundance and diversity of Car- boniferous to Permian acritarchs, and emergence, diversification, and increasing biomass of dinoflagellates in Triassic to Cretaceous rocks. The dinosteroid hydrocar- bon record supplements morphologic and ultrastructural arguments that either mod- ern dinoflagellates evolved from ancient (Precambrian) acritarchs or early dinoflag- ellates did not commonly encyst. In either case the chemical lineage shown by the dinosteroid hydrocarbons indicates a heritage that dates at least from the Riphean. IN A SURVEY OF marine rocks of various geological ages, Moldowan et al. (1996) reported triaromatic dinosteroids (1—numbers in this style refer to figure 21.1) in Precambrian to Devonian organic-rich sedimentary rocks. Also, in an earlier report Summons et al. (1992) noted dinosterane (2) occurrences in extracted organic matter from Precambrian rocks. These data appear to provide the long sought-for evidence that dinoflagellates (or closely related protists) have an ancient origin, a hypothesis 21-C1099 8/10/00 2:20 PM Page 474 MOLECULAR FOSSILS DEMONSTRATE PRECAMBRIAN ORIGIN OF DINOFLAGELLATES 475 previously suggested by evolutionary biologists. Dinoflagellates are to a large extent primary producers, and rRNA and ultrastructure studies suggest their primitive na- ture (Margulis 1970; Wainright et al. 1993). Proof of a pre-Mesozoic diagnostic sig- nature could provide pivotal information for understanding and reconstructing an- cient food webs and the presence of environmentally important zooxanthellae-driven carbonate precipitation (Fensome et al. 1993), despite the apparent absence of defini- tive examples of dinoflagellate cysts in the Paleozoic and Precambrian record. Dinoflagellates are the nearly exclusive producers of dinosterols (3). An excep- tion was noted by Volkman et al. (1993) in a marine diatom. Dinosterols, in turn, are the biochemical precursors for the geologically preserved dinosteroid hydrocarbons (dinosteranes, triaromatic dinosteroids). These dinosteroid compounds are part of a large group of geologically preserved hydrocarbons known as biomarkers. Biomark- ers are defined as “complex organic compounds composed of carbon, hydrogen, and other elements which are found in oil, bitumen, rocks and sediments and show little or no change in structure from their parent organic molecules in living organisms” (Peters and Moldowan 1993). Organic geochemical data on dinosteranes (2) are presented here, in addition to the detailed triaromatic dinosteroid hydrocarbon (1) information omitted from Moldo- wan et al. (1996) in the abbreviated journal format. This information supports the concept of a pre-Mesozoic chemical record of dinoflagellates or closely related forms. Figure 21.1 Steroid structures mentioned in text: 1, triaromatic dinosteroid; 2, dinosterane; 3, dinosterol (most abundant structure); 4, 4a- methylstigmastane; 5, 3b-methylstigmastane; 6, stigmastane; 7, ergostane; 8, triaromatic 3-methyl-24-ethylcholesteroid; 9, triaromatic 2-methyl-24-ethylcholesteroid; 10, triaromatic 4-methyl-24-ethylcholesteroid; 11, gorgosterol and 4a-methylgorgosterol; 12, 27-norcholest- 5,22-en-3b-ol; 13, 24-norcholest-5,22-en-3b-ol. 21-C1099 8/10/00 2:20 PM Page 475 476 J. M. Moldowan, S. R. Jacobson, J. Dahl, A. Al-Hajji, B. J. Huizinga, and F. J. Fago Dinoflagellates’ probable endosymbiotic origin is based on ultrastructure studies (Margulis 1970). Such a symbiotic incorporation of organelles representing discrete taxonomic entities as organelles, and therefore multiple sources of discrete genetic material merged in a single cell, has presented conundrums to those evolutionary bi- ologists and paleontologists trying to use the conventional “tree” model for describ- ing evolution of single-celled taxa. Statistical treatment of rRNA data (Wainright et al. 1993: figure 1) shows dinoflagellates (included as alveolates) diverging relatively early. Based primarily on ultrastructure, Taylor (1994) has provided a “tree” that also shows dinoflagellates with an ancient origin. He cites the triple-membraned envelopes of dinoflagellates and their multiple nuclei as evidence of likely endosymbiotic origin. Ambiguities in microbiological evolution introduced by endosymbiosis, rather than by mutation, also cloud chemocladistic evolutionary interpretations. Therefore, we believe our empirical data from the fossil record adds new information for address- ing the ancient origin for the dinoflagellate lineage. METHODS We analyzed extracts from 129 organic-rich stratigraphically dated samples from Pro- terozoic to Cretaceous age cores, side-wall cores, and outcrop samples for triaromatic dinosteroids and dinosteranes (1 and 2; table 21.1). The rock samples were screened for percentage of total organic carbon (Ͼ1 percent) and Rock-Eval pyrolysis param- eters useful for discriminating contamination by migrated oil (Peters 1986). Dinosteranes (2) were identified by gas chromatography–mass spectrometry– mass spectrometry (GC-MS-MS) coelution experiments, using synthetic standards of four (20R)-5a-dinosterane diastereomers having the 20R,23S,24R (RSR), RRR, RSS, and RRS stereochemistries (Stoilov et al. 1993). Other methyl steranes, namely (20R)- 4a-methylstigmastane (4) (Stoilov et al. 1993) and (20R)-3b-methylstigmastane (5) (Summons and Capon 1988), were identified by similar means. Dinosteranes were detected and measured using m /z 414 l 98 and 414 l 231 GC-MS-MS transitions on a Hewlett-Packard 5890 Series II GC coupled to a VG Micromass Autospec Q hy- brid mass spectrometer system at Stanford University. The m /z 414 l 98 transition is highly selective for dinosteranes over other methylsteranes and was used for identi- fication. The more intense m /z 414 l 231 transition was used for quantification of dinosteranes and methylstigmastanes. Because of partial coelution interferences from other steranes in the m /z 414 l 231 transition, it was necessary to measure dino- steranes in the m/z 414 l 98 transition in some cases and to apply a correction fac- tor to obtain the amount consistent with m/z 414 l 231 measurements. Because of the great effect of thermal maturation on absolute biomarker concen- trations, we followed an approach suggested by Peters and Moldowan (1993), using ratios of biomarkers of similar thermal stability, that is, ratios of dinosteranes with structurally similar steranes rather than absolute concentrations of dinosterane. Con- 21-C1099 8/10/00 2:20 PM Page 476 MOLECULAR FOSSILS DEMONSTRATE PRECAMBRIAN ORIGIN OF DINOFLAGELLATES 477 centration effects caused by thermal maturity cancel out in such ratios and yield re- sults indicating one biomarker input compared with another, which reflects the rela- tive contributions of two taxa to a given sample. RESULTS Dinosterane (2) data, presented in figure 21.2, were recorded in ratios to (20R)-4a- methylstigmastane (4), (20R)-3b-methylstigmastane (5), (20R)-5a-stigmastane (6), and (20R)-5a-ergostane (7). Precursors for the denominator compounds appear to be less restricted in modern organisms and environments than dinosterols (3). The 4a-methylstigmastanes are related to 4a-methyl-24-ethylcholesterols found in both dinoflagellates and haptophytes (synonym “prymnesiophytes,” sensu Siesser 1993) (Volkman et al. 1990). However, the occurrence of 4a-methylstigmastane precursors is much more restricted than those of stigmastane itself. Two possible stigmastane pre- cursors, fucosterol and isofucosterol, have been found in Dinophyceae but, if present, are generally minor sterols. These and other stigmastane precursors are widespread major or minor sterols in some members of virtually all the algal families (Volkman 1986). The same can be said for ergostane precursors, except they have not been found in the Dinophyceae. The precursors of 3-methylstigmastanes are unknown in modern organisms. These modified steranes are ubiquitous in rock extracts and oils and are thought to be derived by microbial alkylation of 2-sterenes produced during diagene- sis from common desmethylsterols (Summons and Capon 1988, 1991; Dahl et al. 1992). Therefore, 3-methylstigmastanes are likely to have the same widespread algal origins as stigmastanes. The (desmethyl) stigmastane precursors stigmasterol and si- tosterol are common to algae and vascular plants, which were important contributors to some paleodepositional environments. Triaromatic dinosteroids were compared (figure 21.3) in ratios to triaromatic 3-methyl-24-ethylcholesteroids (8) plus triaromatic 2-methyl-24-ethylcholesteroids (9) and to triaromatic 4-methyl-24-ethylcholesteroids (10) (Dahl et al. 1995). The key triaromatic dinosteroids were analyzed in rock-extract aromatic fractions pre- pared by high-performance liquid chromatography (Peters and Moldowan 1993), us- ing gas chromatography–mass spectrometry for monitoring the m/z 245 ion (loss of side chain), and identified by coelution with authentic standards (Ludwig et al. 1981; Lichtfouse et al. 1990; Shetty et al. 1994; Stoilov et al. 1994). The precur- sors for compounds selected as denominators in these ratios appear to be widely distributed in modern organisms or environments. The precursors of triaromatic 3-methyl-24-ethylcholesteroids (8) and triaromatic 2-methyl-24-ethylcholesteroids (9), like their saturated analogs, appear to be formed by diagenesis of 4-desmethyl- sterols. The triaromatic 4-methyl-24-ethylcholesteroids (10) are related to 4-methyl- 24-ethylcholesterols, which are abundant both in dinoflagellates and prymnesio- phytes (Volkman et al. 1990). 21-C1099 8/10/00 2:20 PM Page 477 478 J. M. Moldowan, S. R. Jacobson, J. Dahl, A. Al-Hajji, B. J. Huizinga, and F. J. Fago Table 21.1 Identification of Samples and Measurements of Their Dinosteroid Ratios SAMPLE ID COUNTRY-REGION BASIN FORMATION DEPTH A565 Australia McArthur Velkerri 181.3 m A564 Australia McArthur McMinn 64.0 m A468 US/Arizona Colorado Plateau Kwagunt, Chuar Surface A466 US/Arizona Colorado Plateau Kwagunt, Chuar Surface S2 Middle East Central Arabia Huqf Ͼ1,000 m A476 Middle East Central Arabia Huqf 4,447 m C9 US/Missouri ? Bonneterre 2,337 ft 333 US/North Dakota Williston ? ? S3 Middle East Central Arabia Huqf Ͼ1,000 m C151 E. Siberia, Russia Yudoma-Olenek Kuonamka Surface S1 Middle East Central Arabia Huqf Ͼ2,000 m C152 E. Siberia, Russia Yudoma-Olenek Kuonamka Surface A316 E. Siberia, Russia Yudoma-Olenek Kuonamka Surface? C156 E. Siberia ? ? Surface A221 Australia Georgina Inca 107.6 m A220 Australia Georgina Currant Bush 22.18 m A197 Sweden ? Alum Shale 44.88 m A198 Sweden ? Alum Shale 24.21 m A200 Sweden ? Alum Shale 22 m A199 Sweden ? Alum Shale 9 m 315 USSR ? Dictyonema Ͻ1,000 m A569 Australia Amadeus Horn Valley 227.9 m A568 Australia Amadeus Horn Valley 217.5 m A436 Australia Amadeus Horn Valley 216.5 m A382 Middle East Central Arabia Hanadir 14,829 ft A229 Australia Canning Goldwyer 936 m A333 US/Iowa ? Glenwood 752.1 ft A030 US/Iowa Decorah-Guttenberg 953.3 ft A330 US/Nevada Basin & Range Province Vinini 8 ft A437 US/Iowa ? St. Peter 761 ft A900 Jordan ? ? 2,576 m C25 US/Nevada Vinini Cr Surface A242 Libya Cryenacian Platform ? A291 Algeria Ghadames Rhazziane 3,214 m A289 Algeria Illizi ? 2,083 m A332 US/Iowa Maquoketa Shale 461.6 ft A241 Libya Sirte ? A383 Middle East Central Arabia Qusaiba 13,505 ft A288 Algeria Ghadames Oued Ali ? A449 Bolivia South Sub-Andean FTB ? 2,191.5 m A448 Bolivia South Sub-Andean FTB ? 2,188.9 m A447 Bolivia Chaco ? A376 Middle East Central Arabia Jauf 14,379 ft A239 Russia Timan-Pechora ? 4,028–4,034 m A237 Russia Timan-Pechora ? 3,700 –3,708 m 21-C1099 8/10/00 2:20 PM Page 478 MOLECULAR FOSSILS DEMONSTRATE PRECAMBRIAN ORIGIN OF DINOFLAGELLATES 479 BIOMARKER RATIOS* PERIOD AGE 2/(2؉5) 2/(2؉7) 2/(2؉6) 2/(2؉4) 1/(1؉8؉9) 1/(1؉10) M. Pro. Riphean 0.131 0.104 0.713 0.496 0.000 0.000 M. Pro. Riphean 0.104 0.064 0.915 0.365 0.727 0.842 E. L. Pro. Sturtian 0.213 0.263 0.766 0.539 0.000 0.000 E. L. Pro. Sturtian 0.130 0.055 0.648 0.360 0.224 0.437 L. L. Pro. L.V. 0.000 0.000 0.000 0.000 n/a n/a L. Pro. Vendian n/a n/a n/a n/a 0.741 0.785 Cam. 0.047 0.032 0.373 0.152 n/a n /a Cam. ? 0.077 0.051 0.336 0.207 0.000 0.000 E. Cam. 0.000 0.000 0.000 0.000 n/a n /a E. Cam. 0.039 0.007 0.321 0.051 n/a n /a E. Cam. 0.000 0.000 0.000 0.000 n/a n /a E. Cam. 0.028 0.006 0.243 0.042 n/a n /a E. M. Cam. ? 0.067 0.045 0.565 0.777 0.000 0.000 M. Cam. 0.228 0.079 0.242 0.396 n/a n /a M. Cam. L. Templeton–Floran 0.088 0.050 0.522 0.481 0.000 0.000 M. Cam. Floran-Undillan 0.042 0.000 0.329 0.102 0.000 0.000 M. Cam. 0.051 0.012 0.619 0.140 0.000 0.000 L. Cam. 0.095 0.054 0.548 0.498 L L E. Ord. Tremadocian 0.000 0.000 0.000 0.000 L L E. Ord. Tremadocian 0.086 0.042 0.480 0.250 0.000 0.000 E. Ord. ? 0.110 0.080 0.468 0.441 0.000 0.000 E. Ord. Arenigian 0.169 0.100 0.476 0.387 L L E. Ord. Arenigian 0.062 0.048 0.607 0.280 L L E. Ord. Arenigian 0.000 0.000 0.000 0.000 L L M. Ord. ? 0.050 0.070 0.604 0.505 0.777 0.836 M. Ord. Llanvirnian 0.000 0.000 0.000 0.000 0.000 0.000 M. Ord. E. Caradocian 0.141 0.080 0.336 0.394 0.000 0.000 M. Ord. E. Caradocian 0.115 0.030 0.426 0.153 0.000 0.000 M. Ord. E. Caradocian 0.277 0.190 0.495 0.592 0.769 0.787 M. Ord. E. Caradocian 0.003 0.006 0.142 0.077 0.000 0.000 M. Ord. E. Caradocian 0.000 0.000 0.000 0.000 0.838 0.850 M. L. Ord. 0.039 0.016 0.311 0.114 n/a n /a L. Ord. Caradocian 0.260 0.147 0.524 0.464 0.611 0.767 L. Ord. Caradocian 0.312 0.190 0.520 0.542 0.378 0.616 L. Ord. Caradocian 0.287 0.113 0.584 0.453 0.000 0.000 L. Ord. M. Ashgillian 0.085 0.019 0.347 0.159 0.000 0.000 E. Sil. Llandoverian 0.047 0.074 0.464 0.311 0.647 0.467 E. Sil. ? 0.000 0.000 0.000 0.000 0.373 0.589 Sil. ? 0.057 0.027 0.348 0.133 0.000 0.000 L. Sil. Ludlovian 0.061 0.035 0.569 0.189 0.117 0.313 L. Sil. Ludlovian 0.008 0.005 0.296 0.101 0.060 0.145 E. Dev. ? 0.030 0.012 0.130 0.135 0.000 0.000 E. Dev. ? 0.000 0.000 0.000 0.000 L L E. Dev. Emsian 0.000 0.000 0.000 0.000 0.000 0.000 E. Dev. Emsian 0.115 0.055 0.333 0.260 0.000 0.000 (continues) 21-C1099 8/10/00 2:20 PM Page 479 480 J. M. Moldowan, S. R. Jacobson, J. Dahl, A. Al-Hajji, B. J. Huizinga, and F. J. Fago Table 21.1 (Continued) SAMPLE ID COUNTRY-REGION BASIN FORMATION DEPTH A446 Bolivia ? Tita ? A605 Bolivia Sub-Andean ? ? C73-d93 Bolivia ? ? ? A606 Bolivia Sub-Andean ? ? A604 Bolivia Sub-Andean ? ? A602 Bolivia Sub-Andean ? ? A949 Bolivia ? ? ? A940 Bolivia ? ? ? A445 Bolivia ? ? ? A227 USA ? Woodford Shale 8,943 ft 654 US/North Dakota Williston Bakken (Upper Member) 10,002 ft A948 UK /Manchester ? ? Surface A226 US/Oklahoma Anadarko Big Lime 4,022.2 ft A225 US/Utah Paradox Hermosa 2,782 ft A190 US/Texas Palo Duro Motley Co., Texas 5,461–5,471 ft A391 Middle East Central Arabia Unayzah 6,196 ft C73-d3 Bolivia ? Bolivia ? A603 Bolivia Sub-Andean ? ? A601 Bolivia Sub-Andean ? ? A559P Brazil ? ? ? A367 Brazil Parana Irati ? A337 US/Montana Rocky Mountain Phosphoria (Mead Peak Member) 408.5 ft A342 US/Montana Rocky Mountain Phosphoria (Mead Peak Member) 431.5 ft A336 US/Montana Rocky Mountain Phosphoria (Mead Peak Member) 207 ft A335 US/Montana Rocky Mountain Phosphoria (Mead Peak Member) 205 ft C124 Svalbard Sticky Keep ? C125 Svalbard Sticky Keep ? A576 US/Alaska Surface A416 US/ Wyoming ? Dinwoody 34.1 ft A415 US/ Wyoming ? Dinwoody 32.1 ft A414 US/ Wyoming ? Dinwoody 30.9 ft C123 Svalbard Botneheia ? 393 Switzerland Southern Alps FTB Meride Shale 327–332 ft 898 Syria Northwest Arabian ? 675–825 m 280 US/Idaho Thaynes Limestone 1,941 ft 208 US/Alaska North Slope Shublik 8,891–8,903 ft 207 US/Alaska North Slope Shublik 8,825–8,830 ft 797 Italy Central Apennines Dolomia Principale Surface A793 Papua New Guinea South Papuan FTB Koi-Iange ? 213 US/Alaska North Slope Kingak Shale 9,390 ft 210 US/Alaska North Slope Kingak Shale 8,399–8,405 ft 21-C1099 8/10/00 2:20 PM Page 480 MOLECULAR FOSSILS DEMONSTRATE PRECAMBRIAN ORIGIN OF DINOFLAGELLATES 481 BIOMARKER RATIOS* PERIOD AGE 2/(2؉5) 2/(2؉7) 2/(2؉6) 2/(2؉4) 1/(1؉8؉9) 1/(1؉10) Dev. ? 0.067 0.026 0.250 0.212 0.000 .000 M. Dev. L. Givetian 0.091 0.040 0.539 0.247 0.000 .000 L. Dev. ? 0.057 0.026 0.473 0.127 n/a n /a L. Dev. Frasnian 0.111 0.035 0.384 0.279 0.351 0.585 L. Dev. Frasnian 0.091 0.031 0.494 0.177 0.000 0.000 L. Dev. Frasnian 0.076 0.023 0.604 0.228 0.114 0.259 L. Dev. ? 0.078 0.024 0.267 0.175 0.000 0.000 L. Dev. ? 0.103 0.034 0.576 0.166 0.000 0.000 L. Dev. ? 0.036 0.019 0.401 0.140 0.000 0.000 Car Dev. 0.049 0.014 0.280 0.077 0.076 0.236 E. Car. Kinderhookian 0.074 0.026 0.320 0.190 0.069 0.157 E. Car. E. Namurian 0.000 0.000 0.000 0.000 L L M. Car. Desmoinesian 0.075 0.047 0.430 0.241 0.121 0.399 M. Car. Desmoinesian 0.020 0.013 0.347 0.098 0.000 0.000 M.–L. Car. Penn. 0.018 0.007 0.177 0.189 0.000 0.000 Per Car. 0.013 0.013 0.647 0.075 0.000 0.000 Per. 0.070 0.012 0.343 0.080 n/a n /a E. Per. Aktas Leonard. 0.016 0.015 0.502 0.194 0.000 0.000 E. Per. Aktas Leonard. 0.019 0.018 0.571 0.202 0.000 0.000 E. Per. Art Kungurian 0.022 0.005 0.614 0.069 0.000 0.000 E. Per. Art Kungurian 0.027 0.005 0.345 0.106 0.000 0.000 E. Per. Leonardian 0.037 0.027 0.648 0.268 0.000 0.000 E. Per. Leonardian 0.096 0.064 0.378 0.285 0.000 0.000 E. Per. Guadalupian 0.050 0.025 0.569 0.177 0.000 0.000 L. Per. Guadalupian 0.039 0.021 0.537 0.154 0.000 0.000 E. Tri. 0.043 0.018 0.350 0.147 n/a n /a E. Tri. 0.053 0.024 0.336 0.185 n/a n /a E. Tri. n/a n/a n/a n/a 0.808 0.649 E. Tri. E. Scythian 0.351 0.174 0.521 0.518 0.615 0.824 E. Tri. E. Scythian 0.088 0.066 0.799 0.437 0.154 0.332 E. Tri. E. Scythian 0.073 0.046 0.627 0.291 0.300 0.467 0.038 0.016 0.260 0.126 n/a n /a M. Tri. Anisian-Landinian 0.479 0.221 0.815 0.782 0.915 0.814 Tri. ? 0.151 0.043 0.683 0.646 0.633 0.616 Tri. ? 0.254 0.200 0.725 0.524 0.662 0.756 Tri. ? 0.261 0.154 0.631 0.425 0.632 0.714 Tri. ? 0.275 0.169 0.633 0.531 0.593 0.701 L. Tri. Norian 0.463 0.116 0.648 0.873 0.920 0.783 M. Jur. E. M. Callovian 0.391 0.113 0.951 0.408 n/a n/a L. Jur. ? 0.254 0.150 0.754 0.536 0.813 0.808 L. Jur. ? 0.257 0.127 0.596 0.532 0.801 0.833 (continues) 21-C1099 8/10/00 2:20 PM Page 481 482 J. M. Moldowan, S. R. Jacobson, J. Dahl, A. Al-Hajji, B. J. Huizinga, and F. J. Fago Table 21.1 (Continued) SAMPLE ID COUNTRY-REGION BASIN FORMATION DEPTH 313 Australia Barrow Dampier Dingo Claystone 2,835 ft 314 Australia Barrow Dampier Dingo Claystone 2,545 ft 997 UK North Sea 6,888 ft 993 Scotland Celtic Sea Cullaidh A793 Papua New Guinea South Papuan Koi-Iange 413 Middle East Central Arabia Tuwaiq Mountain 6,815 ft 412 Middle East Central Arabia Hanifa 6,540 ft A789P UK North Sea Kimmeridge Clay 5,320 ft 410 Middle East Central Arabia Hanifa 1,009 ft A790 Papua New Guinea South Papuan FTB Imburu Surface A788P UK North Sea Kimmeridge Clay 5,320 ft A799 Papua New Guinea South Papuan FTB Imburu 9,380 ft A791 Papua New Guinea South Papuan FTB Imburu Surface A142 Russia West Siberia Bazhenov 2,773 m A798 Papua New Guinea South Papuan FTB Leru 7,880 ft A503 Argentina Neuquen Vaca Muerta Surface 312 Australia Barrow Dampier Muderong Shale 1,291 m 209 US/Alaska North Slope ? 11,568 ft A619 Colombia Upper Magdalena Paja Surface A631P Italy South Alps FTB ? Surface A627P Ecuador Oriente Napo 295 m A617 Colombia Upper Magdalena Surface A629P Australia Eromanga Toolebuc ? A616 Colombia Upper Magdalena Similti Surface A539P Angola Lower Congo Vermelha 9,500 ft A630P Italy South Alps FTB ? Surface A533 Angola Lower Congo Vermelha 7,088 ft A600 Bolivia Sub-Andean Basin ? Surface C34 US/Colorado ? ? A554P Angola Lower Congo Vermelha 8,233 ft A411 Ecuador Oriente Napo 144 m A547P Angola Lower Congo Vermelha 6,100 ft 226 US/Alaska North Slope Seabee Shale 11,161 ft A552 Angola Lower Congo Vermelha 7,536 ft A545 Angola Lower Congo Vermelha 5,366 ft 583 US/ Wyoming Hilliard (Upper Member) 70 –80 ft A623 US/California San Joaquin ? 14,112 ft A543 Angola /Cabinda Lower Congo Vermelha 4,545 ft A613 Colombia Upper Magdalena LaLuna Surface A608P Colombia Upper Magdalena LaLuna Surface A537 Angola Lower Congo Labe 9,952 ft A386 Trinidad Onshore Trinidad Naparima Hill Surface A385 Trinidad Onshore Trinidad Naparima Hill Surface *Refer to Figure 21.1 and text for compound structures and names. n/a ϭ measurement not taken. L ϭ low biomarker concentrations. 21-C1099 8/10/00 2:20 PM Page 482 MOLECULAR FOSSILS DEMONSTRATE PRECAMBRIAN ORIGIN OF DINOFLAGELLATES 483 BIOMARKER RATIOS* PERIOD AGE 2/(2؉5) 2/(2؉7) 2/(2؉6) 2/(2؉4) 1/(1؉8؉9) 1/(1؉10) L. Jur. ? 0.409 0.197 0.673 0.477 0.616 0.632 L. Jur. ? 0.082 0.043 0.565 0.304 0.516 0.776 M. Jur. n/a n/a n/a n/a 0.353 0.615 M. Jur. Bathonian n/a n /a n /a n /a 0.955 0.920 M. Jur. E.–M. Callovian n/a n/a n/a n/a .492 0.719 L. Jur. Oxfordian 0.296 0.139 0.597 0.429 0.892 0.811 L. Jur. L. Oxfordian 0.421 0.147 0.487 0.408 0.830 0.746 L. Jur. Oxford.–E. Kimm. 0.139 0.078 0.645 0.532 n/a n /a L. Jur. L. Oxford.–Kimm. 0.298 0.132 0.422 0.334 0.683 0.769 L. Jur. E. Kimmeridgian 0.454 0.154 0.645 0.514 0.788 0.809 L. Jur. Kimmeridgian 0.346 0.182 0.800 0.618 L L L. Jur. L. Kimmeridgian 0.175 0.080 0.683 0.328 0.684 0.785 L. Jur. E. Tithonian 0.522 0.284 0.668 0.673 0.840 0.803 L. Jur. Volgian 0.189 0.159 0.627 0.428 0.827 0.863 E. Cret. L. Berriasian 0.252 0.145 0.587 0.479 0.815 0.826 E. Cret. Berriasian L. Valang. 0.366 0.328 0.744 0.583 0.627 0.730 E. Cret. Hauterivian 0.099 0.092 0.460 0.579 0.807 0.528 E. Cret. Barremian-Albian 0.099 0.104 0.493 0.395 0.876 0.826 E. Cret. L. Haut.–L. Berri. n/a n/a n/a n/a 0.842 0.807 E. Cret. Aptian 0.080 0.035 0.588 0.246 0.311 0.502 E. Cret. Aptian n/a n/a n/a n/a 0.821 0.851 E. Cret. L. M. Albian 0.164 0.171 0.694 0.443 0.794 0.863 E. Cret. L. Albian 0.079 0.112 0.614 0.492 0.676 0.825 L.–E. Cret. E. Cenomanian 0.248 0.266 0.762 0.734 0.768 0.810 L. Cret. E. Cenomanian 0.184 0.151 0.632 0.455 0.638 0.771 L. Cret. Cenomanian 0.073 0.041 0.580 0.264 0.330 0.605 L. Cret. L. Cenomanian 0.079 0.115 0.640 0.711 0.853 0.860 L. Cret. Cenomanian-Turonian 0.174 0.122 0.655 0.605 0.527 0.735 L. Cret. L. Turonian 0.035 0.029 0.358 0.002 n/a n/a L. Cret. Turonian 0.134 0.121 0.552 0.616 0.590 0.720 L. Cret. Turonian 0.241 0.246 0.674 0.627 0.877 0.893 L. Cret. Coniacian 0.175 0.130 0.562 0.512 0.688 0.764 L. Cret. ? 0.033 0.062 0.535 0.522 0.775 0.823 L. Cret. Santonian 0.099 0.130 0.480 0.536 0.762 0.835 L. Cret. Santonian 0.165 0.189 0.614 0.669 0.791 0.862 L. Cret. Santonian 0.072 0.078 0.548 0.283 0.848 0.719 L. Cret. Campanian 0.051 0.012 0.534 0.480 0.763 0.835 L. Cret. Campanian 0.035 0.150 0.580 0.599 0.752 0.809 L. Cret. L. Campanian 0.158 0.205 0.615 0.607 0.932 0.932 L. Cret. L. Campanian 0.283 0.316 0.682 0.744 0.733 0.819 L. Cret. L. Campanian 0.223 0.221 0.663 0.392 0.692 0.755 L. Cret. L. Campanian–Maast. 0.226 0.236 0.691 0.617 0.870 0.898 L. Cret. Maastrichtian 0.235 0.215 n/a n/a 0.845 0.891 21-C1099 8/10/00 2:20 PM Page 483 [...]... Neoproterozoic-Ordovician transition, 174; Burgess Shale–type faunas, 406; and Cambrian ecology, 420 21; conclusions on, 421; current dominance of, 405; data sources for, 406 –7; in deep-water benthic community, 287; definition of, 406; difficulties relating to study of, 405; early arthropod ecology, 418–19; ecology of, in Cambrian, 404 21; ecology of taxa of, 408–15; evolution of arthropod ecology, 419–20;... migrations, and 4-methylsteroid precursors could be responsible for 2- and 3-methyl-substituted triaromatics (or the reverse) Furthermore, a methyl shift (from C-10 to C-1 or C-4) in the aromatization of sterols can result in a methyl at the 4-position in ring-A monoaromatic steroids derived from 4-desmethylsterols found in thermally immature sediments These compounds could also form 4-methyl triaromatic... Carlson, F J Fago, and J M Moldowan 1994 Synthesis of biomarkers in fossil fuels: C-23 and C-24 diastereomers of (20R)4,17,23,24-tetramethyl-18,19-dinorcho- Stoilov, I., E Kolaczkowska, D S Watt, R M K Carlson, F J Fago, and J M Moldowan 1993 Synthesis of biological markers in fossil fuels 7 Selected diastereomers of 4-methyl-5-stigmastane and 5-dinosterane Journal of Organic Chemistry 58 : 3444 –3454 Stoilov,... them entirely Modern dinoflagellates have been found to carry either or both kinds of sterol (Withers 1987), unusually functionalized 4-methyl-24-ethylcholest-8(14)-en-3-ols (containing a C-ring double bond) that are ideally set up for aromatization, and 4-methyl-24-ethylcholestan-3-ols that are fully saturated CONCLUSIONS Our geologically well-dated, chemostratigraphic data show that lower Paleozoic rocks... early Mesozoic radiation of dinoflagellates Paleobiology 22 : 329–238 Goad, L J and N W Withers 1982 The identification of 27-nor (24R )-2 4-methylcholesta-5,22-dien-3b-ol and brassicasterol as the major sterols of the marine dinoflagellate Gymnodinium simplex Lipids 17 : 853–858 Goodman, D K 1987 Dinoflagellate cysts in ancient and modern sediments In F J R 491 Taylor, ed., The Biology of Dinoflagellates, pp... upon further diagenesis (Hussler et al 1981) Therefore, diagenetic rearrangements could also explain the similarities in triaromatic dinosteroids to triaromatic 2- ϩ 3-methyl-24-ethylcholesteroids ratios (figure 21. 3A) and to triaromatic 4-methyl-24-ethylcholesteroids ratios (figure 21. 3B) However, it is not certain that these rearrangement mechanisms are active here Opposing these mechanisms is the fact... amounts of only the 4-methyl and not 1-, 2-, or 3-methyl isomers of triaromatic dinosteroids are present in these samples They would require, then, a selective methyl rearrangement active in the triaromatic 24ethylcholesteroid series and not active in the triaromatic dinosteroid series Thus, it appears unlikely that methyl rearrangements contribute in any significant way to the formation of the analyzed... dinosterols and their diagenetic dinosteroids The function of these sterols is poorly understood It has been presumed that they are membrane constituents, but dinosterol esters have been isolated from extraplastid lipid globules of the dinoflagellate eyespot (Withers and Nevenzel 1977; Withers and Haxo 1978) Therefore, the function and localization of these sterols remains unknown (Withers 1987) The unusual... 1982) and recorded them by geologic age (figures 21. 2 and 21. 3) Assuming that these steroids are derived exclusively from the dinoflagellaterestricted sterols, our results confirm that the lineage of dinoflagellates is rooted in the Precambrian The occurrence of triaromatic dinosteroids (1) in all of our Upper Triassic to Cretaceous marine rock extracts, and their absence in the Carboniferous-Permian ones,... 175, 178; and brachiopods, 362; calcification of, 462; Cambrian radiation of, 455–56; in deepwater benthic community, 287; environmental ecology of, 457– 60; post -Cambrian, 456; Proterozoic antecedents of, 455; radiation of, 453–56; and reefs, 255, 462; and sedimentary fabrics, 138; in shallow-water level-bottom communities, 217 , 228, 229; taxonomic groups of, 446, 447 See also Calcified algae and bacteria . triaromatic 2-methyl-24-ethylcholesteroid; 10, triaromatic 4-methyl-24-ethylcholesteroid; 11, gorgosterol and 4a-methylgorgosterol; 12, 27-norcholest- 5,22-en-3b-ol; 13, 24-norcholest-5,22-en-3b-ol. 2 1- C1099 8/10/00 2:20 PM Page 475 476. radiation of di- noflagellates. Paleobiology 22:329–238. Goad, L. J. and N. W. Withers. 1982. The identification of 27-nor (24R )-2 4-methyl- cholesta-5,22-dien-3b-ol and brassica- sterol as the major. Carl- son, and J. M. Moldowan. 1994. A syn- thesis of a triaromatic steroid biomarker, (20R,24R )-4 ,17-dimethyl-18,19-dinorstig- masta-1,3,5,7,9,11,13-heptaene, from stig- masterol. Journal of