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14 of 15 people found the following review helpful:
5.0 out of 5 stars
Real Jurassic Park, February 1, 2008
Jurassic West - The Dinosaurs of the Morrison Formation. John Foster.
Jurassic West is one in a series from The Indiana University of Indiana's "Life in Past" volumes. Others have included "Carnivorous Dinosaurs", "The Armored Dinosaurs", "Oceans of Kansas" etc. These books in general were collections of research reports on new finding in the study of osteology and were of interest primarily to specialists in the field. Jurassic West however is of more general interest in that it accumulates a wide range of specialized information gained in the last 125 years of fieldwork at the various sites of the Morrison Formation. Not only dinosaurs are tabulated but the book covers all other types of vertebrates as well as invertebrates, paleoecology and several indepth sections of the geology of the Morrison. This formation is one of the most famous and productive paleontological sites in the world. It was formed as as a floodplain basin within a continant. Though semiarid in parts with sparse forests and surrounded by mountains it had constance sources of water: rivers, streams, lakes and groundwater. The time range in gereral lies within the Kimmeridgian section of the Late Jurassic. The Morrison itself consists of stratigraphic layers of various members (distinctive lithographic facies) and represents about 7 million years. The formation varies in thickness from 98 feet to 990 feet and covers a million square kilometers in eight western states. Most of the productive quarries, and there are some 170 of them, are in Wyoming, South Dakota, Colorado, Utah, Arizona and New Mexico. The great and famous American dinosaurs are from such areas as Como Bluff, Dionsaur National Park, Cleveland-Lloyd Quarry, Black Hills, Howe, Lakes etc. These have produced the giants: Diplodocus, Apatosaurus, Camarasaurus (the most numerous) and Brachiosaurus among the Sauropods as well as such Theropods as Allosaurus and Ceratosaurus. This is all very impressive and when most people think of the Jurassic or the Morrison they think of dinosaurs. But as pointed out by Foster, the Morrison ecosystem contained many other vertebrate types along with invertebrates and a wide range of plants. What I found most interesting is that there are as many taxa of mammals as there are of dinosaurs. Both groups appeared about the same time in the Late Triassic, have had about 75 million years of evolution behind them and have about 85 miilion years ahead before the dinosaurs (non-avian) will bow out. After that the mammals will take over the land and invade the sea as the top vertebrate group. The Morrison also has a unique aspect in that it contains one of the smallest vertebrates of the time, the mammal Amphodon at 0.5oz. and probably the largest that ever lived, Brachiosaurus at about 100,000 lbs.
The book also has extensive coverage of the other vertebrate taxa found. Thus turtles (the most numerous fossil), ray-finned fish, lung fish, sphenodons,frogs, croccodylomorphs,pterosaurs and salamander are noted. It also goes into details of rock types, stratifications and formations. Foster then compares some animal guilds with comparable guilds that occur in other time periods. The Theropods of the Morrison Jurassic are more numerous in taxa, smaller in size with a more gradual size gradation than that found in the Hell's Creek formation of the Cretaceous with it's one huge Tyrannosaurus and few others. The analysis is provocative and fascinating.
This book is a very readable one and of interest to a broad range of biologicaly and geologicaly inclined audiences. It contains enough detail to be a reference book in addition to an approachable text for understanding the complicated biology and geology of this time and place.
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9 of 10 people found the following review helpful:
5.0 out of 5 stars
Wonderfully comprehensive overview of a fascinating ecosystem, May 17, 2008
_Jurassic West_ by John Foster is a comprehensive overview of the geology and biota of the Morrison Formation of Jurassic western North America (roughly 150 million years ago). In this well-illustrated book with many pages of references, the author recounted what the formation is, the types of rocks it is found preserved in, what the environment was like, the history of the study of the Morrison (one of the most intensively studied of all Mesozoic ecologies, it has been explored for over 125 years), and what to me is the heart of the book, a complete list and description of all vertebrate animals found there and the ecology of that region back in the Mesozoic.
So what was the Morrison? It was an immense flat basin between about 30 degrees and 40 degrees north latitude, a floodplain located between highlands to the west and far to the east. Thanks to the western mountains, it existed in something of a rain-shadow and was semi-arid and mostly savanna, though did receive a fair amount of water from surface rivers from the mountains, some regions of rather high groundwater levels, and seasonal storms. Foster wrote that geologist Ralph Moberly proposed that the Gran Chaco Plain of northern Argentina is a very good analog for the Morrison, as it is a vast alluvial plain, well-vegetated with patches of forest scattered through savannas and between lakes and freshwater swamps (some of these bodies of water are seasonal). Most of the rain occurs in the spring and summer during the rainy season, while during the winter dry season some bodies of water become sun-baked mud flats. Of course, the Morrison's savannas didn't have grass, as like other flowering plants they had yet to evolve; instead there were open plains of ferns (more than 80 types are known) and cycadophytes and the scattered lone trees and patches of woodland (mostly around bodies of water) were _Sequoia_ (related to modern redwoods), araucarian conifers (similar to Norfolk Island pines), _Podozamites_ (similar to the kauri tree of New Zealand), ginkgoes, tree ferns, seed ferns, cycads, and horsetails.
Foster recounted the 90 known vertebrate species from the Morrison, including fish, frogs, salamanders, turtles (which were quite abundant), sphenodontians (related to the modern tuatara), lizards, a possible snake, champsosaurs (a crocodile-like group of reptiles - distantly related - that existed as late as the Paleocene), crocodiles (the most interesting was "Fruitachampsa," a long-legged, terrestrial housecat-sized predator), pterosaurs, and mammals, but the main focus is on the dinosaurs, ranging from the predatory _Allosaurus_ (most abundant theropod of the formation, nearly 75% of the theropod specimens) to the huge _Saurophaganax_ (a nearly tyrannosaur-sized allosaurid, only two individuals have been found and it appears to have been quite rare) to smaller theropods such as _Ornitholestes_ (possibly feathered) to the huge sauropods (ranging form _Camarasaurus_, the most abundant dinosaur of the formation to the apparently rare _Brachiosaurus_) to stegosaurs, the rare ankylosaurs (not uncovered until the 1990s), and smaller fleet-footed ornithopods like _Dryosaurus_ and _Camptosaurus_.
Foster wrote that the diversity of mammals was so rich that there were nearly as many mammal genera as there were all groups of dinosaurs combined, showing a real diversity in lifestyles, prey, and habitats. Some forms (_Docodon_) appear to have been semiaquatic like muskrats while others (_Fruitafossor_) were burrowers, showing many similarities to the much later evolved aardvarks and armadillos, with peg-like teeth, spade-like claws, and a robust humerus.
There was an unusually high diversity of large carnivores, both when compared with today and with other past ecosystems. Though the famed Cleveland-Lloyd Quarry in Utah is dominated by _Allosaurus_, five other genera of theropods were found there, which lived in the same place at the same time. Foster compared the theropods of the tyrannosaur-dominated Late Cretaceous Hell Creek Formation and found that the Morrison Formation showed "greater species diversity, less body mass range from smallest to largest, and lesser disparity from one species to next smaller" than at Hell Creek. While Morrison had six species greater than 100 kg (220 lbs) in weight, only three were at Hell Creek (and two of them - an ornithomimid and oviraptorosaur - lacked teeth, so the next "pure carnivore" after _Tyrannosaurus_ was a 35 kg or 77 lb. troodontid). _Tyrannosaurus_ weighs more than 10 times as much as the next theropod, while no such extreme disparity exists at Morrison, where the difference as shown on a chart is "strikingly gradual and steplike." Foster did speculate that perhaps different age groups of _Tyrannosaurus_ functioned in a similar ecological role as the many genera of Morrison.
Foster wondered why this "freak of the Late Cretaceous," an "anomalous Mesozoic carnivore on steroids," was so big; did it really need to be that huge to prey upon hadrosaurs and ceratopsians? Why wouldn't the gargantuan sauropods of Morrison produce "behemoth carnivores?" Foster speculated that adult sauropods and even older juveniles were practically immune from predation so theropods focused on stegosaurs, ornithopods, and smaller sauropods.
How did the theropods of Morrison survive together? Analyzing body size, tooth size, forelimb build, and relative abundance of specimens, Foster proposed that _Allosaurus_ was something of a generalist predator (perhaps even feeding at times on aquatic life such as large lungfish according to Bob Bakker), feeding on a wide variety of prey items, while the larger and more robust _Torvosaurus_ feed on larger dinosaurs and the smaller, more gracile but large-toothed _Ceratosaurus_ fed on midsized dinosaurs.
In contrast to the gradual progression in size ranges in theropods, the herbivores were generally either all very large or rather small, showing a marked "bimodality." Richard Stucky proposed that given the already open terrain of the Morrison and the probable habitat modification thanks to the feeding habits of the sauropods, herbivores were under evolutionary pressure to either evolve into extremely large sizes to be immune to predation or be small to hide in what little understory there was.
The book also has an excellent section on sauropod metabolism where he reviewed concepts like inertial homeothermy and fermentative endothermy.
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2 of 4 people found the following review helpful:
5.0 out of 5 stars
great book, covers the entire Jurassic Morrison ecosystem, May 5, 2008
Th title of this book says it all: its not just about the dinosaurs, but it also tells you about their world. Its a great read and suitable for all readers.
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