View - Kowalewski, M. - Virginia Tech

More documents

Recommendations

Info

PALEONTOLOGICAL SOCIETY PAPERS, V. 8, 2002FIGURE 5—Mesozoic predatory marine vertebrates. 1, Cretaceous ichthyodectid teleost Xiphactinus. 2,Skeleton of the pycnodontid fish Proscinetes, Jurassic. 3, Skull of ichthyodectid teleost fish Cladocyclus,Cretaceous; Late Cretacous. 4, Hybodid shark, Hybodus. 5, Geologic distribution of marine reptiles, fromleft to right: ichthyosaurs, plesiosauroids, pliosauroids, teleosaurs, metriorhynchids, and mosasaurs.6–9, Skeletons of Mesozoic marine reptiles: 6, Mosasaur Plotosaurus, Late Cretaceous. 7, PlesiosauroidMuraenosaurus; Jurassic. 8, Pliosauroid Peloneustus; Late Jurassic. 9, Ichthyosaur Ophthalmosaurus;Early Jurassic. 10, Cretaceous foot-propelled diving bird Hesperornis. 11, Skeleton of Creaceous marinebird Ichthyornithyes. Figures 1–4, 10, 11 adapted from Benton (1997); Figures 5–9 from Massare (1987).136
WALKER AND BRETT—POST-PALEOZOIC PATTERNS IN MARINE PREDATIONdiscretely fall into two basic shapes: from the longnecked,small-headed elasmosaurs to the shortnecked,large-headed pliosauromorphs (O’Keefe,2002). By the Late Cretaceous, these pelagicmarine reptiles were globally distributed (Rieppel,1997). But the taxonomy of this group is still poorlyknown because of the inadequacy of type material,and preservational problems such as skull-lessskeletons (Carpenter, 1997).The plesiosaurs (clade Plesiosauria) wereamong the most diverse, geologically long-lived,and widespread of the Jurassic to Cretaceousmarine reptiles, with a fossil record extending fromthe Triassic-Jurassic boundary to the LateCretaceous (Figs. 5.5, 5.7) (Carroll and Gaskill,1985; Rieppel, 1997). These large reptiles (up to15 m long) had long paddle-shaped limbs(considered hydrofoils), short tails, long necks,needle-shaped conical teeth, and may have swamlike modern sea lions (Godfrey, 1984; Carroll andGaskill, 1985). Plesiosaurs are the only marineanimals in which both forelimbs and hindlimbsperformed as lift-based appendicular locomotion(i.e., as hydrofoils; Storrs, 1993). Pliosaurs had largeskulls (up to 3 m) and jaws with large fang-like teeth(Taylor, 1992), and were capable of dismemberingtheir prey (Taylor and Cruickshank, 1993).The small relative skull size and neck lengthof plesiosaurs, in addition to their dentition,suggests that many of them may have fed on smallfish and soft-bodied cephalopods; some may havealso strained the water for prey (Massare, 1987;Rieppel, 1997). Their evolution may have beenstimulated by the new abundance of largeractinopterygian fishes and sharks in offshoremarine environments. Plesiosaurs from the MiddleJurassic of the Oxford Clay also are thought to havebeen specialists on soft-bodied cephalopods andfish (Martill, 1990). The gastric contents of one LateJurassic plesiosaur, Pliosaurus brachyspondylus,included cephalopod hooklets (Tarlo, 1959). Wetzel(1960) has reported small ammonites in coprolitesattributed to plesiosaurs.Case studies from the Middle Jurassic OxfordClay, United Kingdom, provide a window into themarine trophic relationships of this time period. Thecarnivorous plesiosaurs (Liopleurodon, Pliosaurus)were considered to be at the top of the MiddleJurassic food chain, presumably feeding on fish and“naked” (without a shell) cephalopods (Martill,1990). The ichthyosaur Ophthamosaurus wasthought to be a specialist on naked cephalopods,while marine crocodilians (Metriorhynchus,Steneosaurus) presumably fed on fish and nakedcephalopods (Martill, 1986a, 1986b, 1990). Massare(1987) examined the conical pointed teeth form ofsome Jurassic ichthyosaurs and plesiosaurs, andconcluded that the teeth functioned to pierce softprey. Fish from these deposits were either planktonfeeders or fed on smaller fish, indicating that theMiddle Jurassic had a highly complex marine foodweb (Martill, 1990).Ichthyosaurs.—Lower Jurassic localities fromEurope (e.g., Lyme Regis, England; Holzmaden,Germany) indicate that marine reptile guilds at thistime were dominated by a diverse array ofichthyosaurs (Figs. 5.5, 5.9) (Massare, 1987). Gastriccontents from ichthyosaurs are known from LowerJurassic localities in Europe (Pollard, 1968; Keller,1976; Massare, 1987). The majority of preservedfood remains were cephalopod hooklets (Massare,1987, her table 1, p. 128). For example, preservedcephalopod hooklets (interpreted to be frombelemnites), fish remains, and wood were presentin the gastric contents from the small (< 3 m) LowerJurassic ichthyosaur Stenopterygius (Keller, 1976).Putative phragmoteuthid cephalopods also werepreserved in the stomach contents of the smallLower Jurassic icthyosaur, Ichthyosaurus (Pollard,1968). No belemnite hardparts (besides hooklets)have been reliably found in ichthyosaur gutcontents (Massare, 1987; but see Pollard, 1968).In contrast to the Lower Jurassic, Middle to LateJurassic assemblages indicate a number of changesin the vertebrate predatory ensemble (Massare,1987). Although the same functional feeding types(based on tooth form and wear) were present, thereptile groups were different, with pliosauroids andcrocodiles dominating the assemblages, and withreduced ichthyosaur diversity (Massare, 1987). TheMiddle Jurassic cephalopod-eating ichthyosaur,Ophthalamosaurus (Fig. 5.9) is inferred to have137
Page 1:
THE PALEONTOLOGICAL SOCIETYPAPERSVo
Page 4 and 5:
The Paleontological Society Special
Page 6 and 7:
AuthorsRICHARD K. BAMBACHBotanical
Page 9 and 10:
THE FOSSIL RECORD OF PREDATIONMicha
Page 13 and 14:
INTRODUCTIONTHE FOSSIL RECORD OF PR
Page 15:
KOWALEWSKI—ANALYTICAL METHODSTHE
Page 18 and 19:
PALEONTOLOGICAL SOCIETY PAPERS, V.
Page 20 and 21:
Page 22 and 23:
Page 24 and 25:
Page 26 and 27:
Page 28 and 29:
Page 30 and 31:
Page 32 and 33:
Page 34 and 35:
Page 36 and 37:
Page 38 and 39:
Page 40 and 41:
Page 42 and 43:
Page 44 and 45:
Page 46 and 47:
Page 48 and 49:
Page 50 and 51:
Page 52 and 53:
Page 54 and 55:
Page 56 and 57:
Page 58 and 59:
Page 60 and 61:
Page 62 and 63:
Page 64 and 65:
Page 66 and 67:
Page 68 and 69:
Page 70 and 71:
Page 72 and 73:
Page 74 and 75:
Page 76 and 77:
Page 78 and 79:
Page 80 and 81:
Page 82 and 83:
Page 84 and 85:
Page 86 and 87:
Page 88 and 89:
Page 90 and 91:
Page 92 and 93:
Page 94 and 95:
Page 96 and 97:
Page 98 and 99: PALEONTOLOGICAL SOCIETY PAPERS, V.
Page 198 and 199:
Page 200 and 201:
Page 202 and 203:
Page 204 and 205:
Page 206 and 207:
Page 208 and 209:
Page 210 and 211:
Page 212 and 213:
Page 214 and 215:
Page 216 and 217:
Page 218 and 219:
Page 220 and 221:
Page 222 and 223:
Page 224 and 225:
Page 226 and 227:
Page 228 and 229:
Page 230 and 231:
Page 232 and 233:
Page 234 and 235:
Page 236 and 237:
Page 238 and 239:
Page 240 and 241:
Page 242 and 243:
Page 244 and 245:
Page 246 and 247:
Page 248 and 249:
Page 250 and 251:
Page 252 and 253:
Page 254 and 255:
Page 256 and 257:
Page 258 and 259:
Page 260 and 261:
Page 262 and 263:
Page 264 and 265:
Page 266 and 267:
Page 268 and 269:
Page 270 and 271:
Page 272 and 273:
Page 274 and 275:
Page 276 and 277:
Page 278 and 279:
Page 280 and 281:
Page 282 and 283:
Page 284 and 285:
Page 286 and 287:
Page 288 and 289:
Page 290 and 291:
Page 292 and 293:
Page 294 and 295:
Page 296 and 297:
Page 298 and 299:
Page 300 and 301:
Page 302 and 303:
Page 304 and 305:
Page 306 and 307:
Page 308 and 309:
Page 310 and 311:
Page 312 and 313:
Page 314 and 315:
Page 316 and 317:
Page 318 and 319:
Page 320 and 321:
Page 322 and 323:
Page 324 and 325:
Page 326 and 327:
Page 328 and 329:
Page 330 and 331:
Page 332 and 333:
Page 334 and 335:
Page 336 and 337:
Page 338 and 339:
Page 340 and 341:
Page 342 and 343:
Page 344 and 345:
Page 346 and 347:
Page 348 and 349:
Page 350 and 351:
Page 352 and 353:
Page 354 and 355:
Page 356 and 357:
Page 358 and 359:
Page 360 and 361:
Page 362 and 363:
Page 364 and 365:
Page 366 and 367:
Page 368 and 369:
Page 370 and 371:
Page 372 and 373:
Page 374 and 375:
Page 376 and 377:
Page 378 and 379:
Page 380 and 381:
Page 382 and 383:
Page 384 and 385:
Page 386 and 387:
Page 388 and 389:
Page 390 and 391:
Page 392 and 393:
Page 394 and 395:
Page 396 and 397:
Page 398 and 399:
Page 400 and 401:
Page 402 and 403:
Page 404 and 405:
Page 406 and 407:
Page 408 and 409:
Page 410 and 411:
Page 412:
THE PALEONTOLOGICAL SOCIETY PAPERSP
show all

View - Kowalewski, M. - Virginia Tech

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?