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Miocene monkey beds
BOOK REVIEWS are despicable when judged by moral standards, but it misses the point. Even many religions state that man is born evil and must be brought to salvation. More importantly, in his zest for cataloging adaptive evils, Williams ignores the possibility that the traits underlying morality and religion also evolved by natural selection6–8. By defining morality as outside of nature, Williams makes it the only part of the organic world that cannot be understood from an evolutionary perspective. Despite these criticisms, Plan and Purpose in Nature deserves to be widely read. Williams’ contributions to evolutionary biology come from a simplicity of thought that can be understood by the general reader without losing its intellectual caliber. We are lucky to have such a readable account of such an important subject from one of its greatest contributors.
David Sloan Wilson Dept of Biological Sciences, Binghamton University, Binghamton, NY 13902-6000, USA
References 1 Williams, G.C. (1966) Adaptation and Natural Selection, Princeton University Press 2 Williams, G.C. (1975) Sex and Evolution, Princeton University Press 3 Nesse, R.M. and Williams, G.C. (1994) Why We Get Sick: The New Science of Darwinian Medicine, Times Books 4 Williams, G.C. (1992) Natural Selection: Domains, Levels and Challenges, Oxford University Press 5 Wilson, D.S., ed. (1997) Multilevel Selection, Am. Nat. 150 (Suppl.) 6 Sober, E. and Wilson, D.S. (1998) Unto Others: The Evolution and Psychology of Unselfish Behavior, Harvard University Press 7 Alexander, R.D. (1987) The Biology of Moral Systems, Aldine de Gruyter 8 de Waal, F. (1996) Good Natured: The Origins of Right and Wrong in Humans and Other Animals, Harvard University Press
Miocene monkey beds Vertebrate Paleontology in the Neotropics: The Miocene Fauna of La Venta, Colombia edited by R.F. Kay et al. Smithsonian Institution Press, 1997. £62.50 hbk (xvi + 592 pages) ISBN 1 56098 4 18 X
T
he La Venta Fauna, of Colombia’s Magdalena River valley, is a singularly important record of land vertebrates in the Neogene tropical realm of South Africa. The
40
Magdalena drains into the Atlantic Ocean within five degrees of the equator. It is thus within the present tropical zone, as it was in the Miocene. The La Venta Fauna is one of the phyletically most diverse, and now most comprehensively analysed, suites of medial Miocene mammals, and other vertebrates, of any suite of that age in South America. The La Venta fossils are also among the best-constrained isotopically (and somewhat paleomagnetically) of any age in that continent. As well as preserving the most significant record of ancient New World primates1, the La Venta Fauna provides evidence for the composition of a tropically-adapted mammalian fauna in contrast to those of more temperate suites from Patagonia. This well-organized book derives from a multinational research program initiated in 1985 by R.F. Kay and others at Duke University, with the aim of capitalizing on the leads documented by R.A. Stirton, D.E. Savage, R.W. Fields and others, which introduced the La Venta record of New World monkeys1. The La Venta Fauna is derived from the Honda Group, a succession of nonmarine volcaniclastic conglomerate, sandstone and mudstone that crops out along the Magdalena River valley between the central and eastern Cordillera, in western Colombia, and preserves input from tectonically active elements of the adjacent mountain ranges. The Honda Group is divided into a lower, La Victoria Formation and a conformably overlying Villavieja Formation, but the La Venta Fauna is derived from the entire succession, and yields both the Miocochilius Assemblage Zone and the Laventan Stage/Age of comparable stratigraphic/taxonomic extent. In an apparently retrogressive step, the authors also nominate a less formalized ‘Laventan South American Land Mammal Age’. Based on a combination of radioisotopic and paleomagnetic data obtained since 1986, the Honda Group ranges in age from 13.5 to 11.5 million years. The Villavieja Formation spans an interval of about one million years, with the Monkey bed (at its base) being about 12.5–12.9 million years old, and of medial Miocene age, and it effectively fills a gap between the Santacruzian and Friasian South American Land Mammal Ages of Patagonia, instead of being a Friasian correlate2. The La Venta Fauna accumulated in a tropical region of low relief near sea level, populated by ox-bow lakes in a meandering river belt susceptible to flooding. Moist evergreen forests apparently were extensive and open areas not so widespread as envisioned by Stirton3 and Fields4,5. This is consistent with the La Venta Fauna being comprised of large numbers (70+) of non-volant species, a high proportion of browsing versus grazing
Copyright © 1998, Elsevier Science Ltd. All rights reserved. 0169-5347/98/$19.00
types, a large number of frugivores, and of arboreal forms (especially primates), and relatives of still forest-dwelling marsupials, bats, lizards and birds. The fossil fish and decapods have living counterparts that inhabit major river basins of the region; sirenians have affinities with freshwater forms as well. Fish record a lowland fluvial assemblage, with conditions ranging from open river to anoxic ponds, some areas bordered by fruiting plants. Amphibians suggest forested to rain forest habitats; snakes, forest floor litter; lizards, rain forests. A diversity of crocodiles represent aquatic to terrestrial carnivores. Turtles include aquatic species and savanna-living tortoises. Birds suggest a combination of wetlands and nearby forests. Of mammals from the Monkey Beds, marsupials (11 species in 10 genera) include those comparable to modern arboreal frugivores, possum-like caenolestoids, forest-dwelling microbiotheres and cursorial carnivores (borhyaenoids). Among the xenarthrans, some of the seven sloth species appear to have been arboreal, others terrestrial. The armadillos and glyptodonts are terrestrial (or possibly semifossorial), inhabiting humid forests and grasslands. Rodents are diverse: 28 species in 13 genera in five families. All are caviomorphs, most suggesting forest habitats, but caviids indicate more open conditions. Litopterns, low-crowned herbivores, probably inhabited forest to savanna environments. The high-crowned ungulate, Miocochilius, was cursorial, and probably a grazer. Large-sized herbivores (larger than a tapir), now unknown in South America, are common at La Venta, including a large terrestrial sloth, a toxodont, a leontiniid, and two astrapotheres – forest-dwelling, but creating open spaces for the grazers. Collectively, the diverse bat community indicates a forest habitat. For the primates, humid, tropical forests are indicated. Based on the above, on mammalian community structure and paleobotany, the setting appears to have been a tropical lowland forest with open patches. This contrasts with the extensive savanna grasslands suggested by Stirton1.
Michael O. Woodburne Dept of Earth Sciences, University of California, Riverside, CA 92521, USA
References 1 Stirton, R.A. (1951) Univ. Calif. Publ. Geol. Sci. 28, 315–356 2 Stirton, R.A. (1953) Univ. Calif. Publ. Geol. Sci. 29, 265–348 3 Stirton, R.A. (1953) Bull. Geol. Soc. Am. 64, 603–622 4 Fields, R.W. (1957) Univ. Calif. Publ. Geol. Sci. 32, 207–403 5 Fields, R.W. (1959) Univ. Calif. Publ. Geol. Sci. 32, 405–444 TREE vol. 13, no. 1 January 1998
David Sloan Wilson Dept of Biological Sciences, Binghamton University, Binghamton, NY 13902-6000, USA
References 1 Williams, G.C. (1966) Adaptation and Natural Selection, Princeton University Press 2 Williams, G.C. (1975) Sex and Evolution, Princeton University Press 3 Nesse, R.M. and Williams, G.C. (1994) Why We Get Sick: The New Science of Darwinian Medicine, Times Books 4 Williams, G.C. (1992) Natural Selection: Domains, Levels and Challenges, Oxford University Press 5 Wilson, D.S., ed. (1997) Multilevel Selection, Am. Nat. 150 (Suppl.) 6 Sober, E. and Wilson, D.S. (1998) Unto Others: The Evolution and Psychology of Unselfish Behavior, Harvard University Press 7 Alexander, R.D. (1987) The Biology of Moral Systems, Aldine de Gruyter 8 de Waal, F. (1996) Good Natured: The Origins of Right and Wrong in Humans and Other Animals, Harvard University Press
Miocene monkey beds Vertebrate Paleontology in the Neotropics: The Miocene Fauna of La Venta, Colombia edited by R.F. Kay et al. Smithsonian Institution Press, 1997. £62.50 hbk (xvi + 592 pages) ISBN 1 56098 4 18 X
T
he La Venta Fauna, of Colombia’s Magdalena River valley, is a singularly important record of land vertebrates in the Neogene tropical realm of South Africa. The
40
Magdalena drains into the Atlantic Ocean within five degrees of the equator. It is thus within the present tropical zone, as it was in the Miocene. The La Venta Fauna is one of the phyletically most diverse, and now most comprehensively analysed, suites of medial Miocene mammals, and other vertebrates, of any suite of that age in South America. The La Venta fossils are also among the best-constrained isotopically (and somewhat paleomagnetically) of any age in that continent. As well as preserving the most significant record of ancient New World primates1, the La Venta Fauna provides evidence for the composition of a tropically-adapted mammalian fauna in contrast to those of more temperate suites from Patagonia. This well-organized book derives from a multinational research program initiated in 1985 by R.F. Kay and others at Duke University, with the aim of capitalizing on the leads documented by R.A. Stirton, D.E. Savage, R.W. Fields and others, which introduced the La Venta record of New World monkeys1. The La Venta Fauna is derived from the Honda Group, a succession of nonmarine volcaniclastic conglomerate, sandstone and mudstone that crops out along the Magdalena River valley between the central and eastern Cordillera, in western Colombia, and preserves input from tectonically active elements of the adjacent mountain ranges. The Honda Group is divided into a lower, La Victoria Formation and a conformably overlying Villavieja Formation, but the La Venta Fauna is derived from the entire succession, and yields both the Miocochilius Assemblage Zone and the Laventan Stage/Age of comparable stratigraphic/taxonomic extent. In an apparently retrogressive step, the authors also nominate a less formalized ‘Laventan South American Land Mammal Age’. Based on a combination of radioisotopic and paleomagnetic data obtained since 1986, the Honda Group ranges in age from 13.5 to 11.5 million years. The Villavieja Formation spans an interval of about one million years, with the Monkey bed (at its base) being about 12.5–12.9 million years old, and of medial Miocene age, and it effectively fills a gap between the Santacruzian and Friasian South American Land Mammal Ages of Patagonia, instead of being a Friasian correlate2. The La Venta Fauna accumulated in a tropical region of low relief near sea level, populated by ox-bow lakes in a meandering river belt susceptible to flooding. Moist evergreen forests apparently were extensive and open areas not so widespread as envisioned by Stirton3 and Fields4,5. This is consistent with the La Venta Fauna being comprised of large numbers (70+) of non-volant species, a high proportion of browsing versus grazing
Copyright © 1998, Elsevier Science Ltd. All rights reserved. 0169-5347/98/$19.00
types, a large number of frugivores, and of arboreal forms (especially primates), and relatives of still forest-dwelling marsupials, bats, lizards and birds. The fossil fish and decapods have living counterparts that inhabit major river basins of the region; sirenians have affinities with freshwater forms as well. Fish record a lowland fluvial assemblage, with conditions ranging from open river to anoxic ponds, some areas bordered by fruiting plants. Amphibians suggest forested to rain forest habitats; snakes, forest floor litter; lizards, rain forests. A diversity of crocodiles represent aquatic to terrestrial carnivores. Turtles include aquatic species and savanna-living tortoises. Birds suggest a combination of wetlands and nearby forests. Of mammals from the Monkey Beds, marsupials (11 species in 10 genera) include those comparable to modern arboreal frugivores, possum-like caenolestoids, forest-dwelling microbiotheres and cursorial carnivores (borhyaenoids). Among the xenarthrans, some of the seven sloth species appear to have been arboreal, others terrestrial. The armadillos and glyptodonts are terrestrial (or possibly semifossorial), inhabiting humid forests and grasslands. Rodents are diverse: 28 species in 13 genera in five families. All are caviomorphs, most suggesting forest habitats, but caviids indicate more open conditions. Litopterns, low-crowned herbivores, probably inhabited forest to savanna environments. The high-crowned ungulate, Miocochilius, was cursorial, and probably a grazer. Large-sized herbivores (larger than a tapir), now unknown in South America, are common at La Venta, including a large terrestrial sloth, a toxodont, a leontiniid, and two astrapotheres – forest-dwelling, but creating open spaces for the grazers. Collectively, the diverse bat community indicates a forest habitat. For the primates, humid, tropical forests are indicated. Based on the above, on mammalian community structure and paleobotany, the setting appears to have been a tropical lowland forest with open patches. This contrasts with the extensive savanna grasslands suggested by Stirton1.
Michael O. Woodburne Dept of Earth Sciences, University of California, Riverside, CA 92521, USA
References 1 Stirton, R.A. (1951) Univ. Calif. Publ. Geol. Sci. 28, 315–356 2 Stirton, R.A. (1953) Univ. Calif. Publ. Geol. Sci. 29, 265–348 3 Stirton, R.A. (1953) Bull. Geol. Soc. Am. 64, 603–622 4 Fields, R.W. (1957) Univ. Calif. Publ. Geol. Sci. 32, 207–403 5 Fields, R.W. (1959) Univ. Calif. Publ. Geol. Sci. 32, 405–444 TREE vol. 13, no. 1 January 1998