Book contents
- Frontmatter
- Contents
- Preface
- 1 Introduction
- 2 Phylogenetics of characters and groups, and the classification of taxa
- 3 Problems in understanding metatherian evolution
- 4 Form–function, and ecological and behavioral morphology in Metatheria
- 5 Background to the analysis of metatherian cruropedal evidence
- 6 Mesozoic and Cenozoic: Fossil tarsals of ameridelphians unassociated with teeth
- 7 Cruropedal attributes of living and fossil families of metatherians
- 8 Taxa and phylogeny of Metatheria
- 9 Paleobiogeography and metatherian evolution
- References
- Index
8 - Taxa and phylogeny of Metatheria
Published online by Cambridge University Press: 16 October 2009
- Frontmatter
- Contents
- Preface
- 1 Introduction
- 2 Phylogenetics of characters and groups, and the classification of taxa
- 3 Problems in understanding metatherian evolution
- 4 Form–function, and ecological and behavioral morphology in Metatheria
- 5 Background to the analysis of metatherian cruropedal evidence
- 6 Mesozoic and Cenozoic: Fossil tarsals of ameridelphians unassociated with teeth
- 7 Cruropedal attributes of living and fossil families of metatherians
- 8 Taxa and phylogeny of Metatheria
- 9 Paleobiogeography and metatherian evolution
- References
- Index
Summary
it is necessary to emphasize the distinction between definition and the evidence that the definition is met.…. Another way to put the matter is to say that categories are defined in phylogenetic terms but that taxa are defined by somatic relationships that result from phylogeny and are evidence that the categorical definition is met.
Simpson (1961a, p. 69)That is the basis of the challangefor the incorrigible phylogenetic detective: most puzzle pieces gone and the ones that remain [are] lying their heads off (may be) about their original position in the phylogenetic tapestry. With handicaps of that sort the best we can hope to achieve is an hypothesis of relationships involving the fewest improbable assumptions about the missing parts of the puzzle.
Archer (1984b, p. 760)The known groups of metatherians as I recognize them (and they most likely were not the only marsupial mammals) are classified at the beginning of the book in Chapter 2, and these taxa are diagnosed here. In the diagnoses I cite and discuss taxonomic properties, those well tested ones in which I have confidence, inasmuch as they are the derived features probably present in the last common ancestor of each group (see Rowe, 1987; Szalay et al., 1987). These are the hypothesized (and corroborated to varying degrees) apomorphies of the postulated ancestors in contrast to their respective antecedents. The scientific validity of groups so diagnosed is dependent on all the objective information against which such concepts can be tested.
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- Publisher: Cambridge University PressPrint publication year: 1995