Significance of Fossils in Determining Evolutionary Relationships

Patterson, Colin

doi:10.1146/annurev.es.12.110181.001211

Cited by 277 publications

(154 citation statements)

References 47 publications

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“…It is unclear whether breaking up long branches by dense taxon sampling (Gauthier et al, 1988;Graybeal, 1998) using morphological data on the basis of reduced cost or specimen accessibility (Hillis and Wiens, 2000) will lead to a more accurate assessment of phylogeny. Morphological data from fossil taxa can increase taxon sampling in a way not possible for sequence data, and therefore these data can potentially provide unique character combinations and information on polarity and can alter ideas on character evolution, rooting, and homology assessment (Patterson, 1981;Doyle and Donoghue, 1987;Gauthier et al, 1988;Huelsenbeck, 1991;Smith, 1994Smith, , 1998Benton, 1998). What remains unclear is whether this potential is realized in the context of accurate phylogeny reconstruction, given that these data will suffer from problems discussed above (Figs.…”

Section: More Morphological Characters or Fewer?mentioning

confidence: 99%

Phylogeny Reconstruction: The Role of Morphology

Scotland¹,

Olmstead²,

Bennett³

2003

Systematic Biology

269

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In this article we explore the paradox of why morphological data are currently utilized less for phylogeny reconstruction than are DNA sequence data, whereas most of what we know about phylogeny stems from classifications founded on morphological data. The crucial difference between the two data sources relates to the number of potentially unambiguous characters available, their ease and speed of discovery, and their suitability for analysis using transformational models. We consider that the increased use of DNA sequence data, relative to morphology, for phylogeny reconstruction is inevitable and well founded, but that a crucial issue remains concerning the role of morphology in phylogeny reconstruction. We present the view that rigorous and critical anatomical studies of fewer morphological characters, in the context of molecular phylogenies, is a more fruitful approach to integrating the strengths of morphological data with those of sequence data. This approach is preferable to compiling larger data matrices of increasingly ambiguous and problematic morphological characters.We argue below that a main constraint of morphologybased phylogenetic inference concerns the limited number of unambiguous characters available for analysis in a transformational framework. This problem of a limited number of unambiguous characters is further compounded by obstacles to accurate homology assessment and character coding, which further reduce the number of characters available for analysis. We discuss and disagree with the view that more morphological data should be used in phylogeny reconstruction. Furthermore, we consider the claim that the greatest strength of morphological data-increased taxon sampling-to be mistaken. In the discussion that follows we use "phylogeny reconstruction" to refer to the computer-based algorithmic analyses routinely conducted in systematics today. NUMBERS OF CHARACTERS Accuracy and SupportHillis (1987) cited the increased number of characters as the greatest advantage of molecular data. Increased numbers of characters have been shown to be crucial in relation to issues of accuracy (Hillis, 1987(Hillis, , 1996(Hillis, , 1998Huelsenbeck and Hillis, 1993;Hillis et al., 1994aHillis et al., , 1994bLamboy, 1994;Cummings et al., 1995;Givnish and Sytsma, 1997b;Rosenberg and Kumar, 2001) and support (Felsenstein, 1985;Sanderson, 1995;Bremer et al., 1999) (Figs. 1a, 1b). Although the number of characters needed for accurate phylogeny reconstruction is difficult to estimate, the number of characters needed in simulation studies to recover accurate trees is an order of magnitude greater than that available from morphology

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Section: More Morphological Characters or Fewer?mentioning

confidence: 99%

Phylogeny Reconstruction: The Role of Morphology

Scotland¹,

Olmstead²,

Bennett³

2003

Systematic Biology

269

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“…More characters for a cladistic analysis will always be found in recent taxa than in extinct ones. This fact (and others) has led to the observation that, in practice, fossils have not made much difference in the determination of branching patterns (Patterson 1981).…”

Section: Extinct and Extant Lobe-finned Fishes And The Origin Of Tetrmentioning

confidence: 98%

Molecules, fossils, and the origin of tetrapods

Meyer

Dolven

1992

J Mol Evol

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Summary. Since the discovery of the coelacanth, L a t i m e r i a c h a l u m n a e , more than 50 years ago, paleontologists and comparative morphologists have debated whether coelacanths or lungfishes, two groups of lobe-finned fishes, are the closest living relatives of land vertebrates (Tetrapoda). Previously, Meyer and Wilson (1990) determined partial DNA sequences from two conservative mitochondrial genes and found support for a close relationship of lungfishes to tetrapods. We present additional D N A sequences from the 12S r R N A mitochondrial gene for three species of the two lineages of lungfishes that were not represented in the first study: Protopterus a n n e c t e n s a n d Protopterus aethiopicus from Africa and N e o c e r a t o d u s forsteri (kindly provided by B. Hedges and L. Maxson) from Australia. This extended data set tends to group the two lepidosirenid lungfish lineages (Lepidosiren and Protopterus) with N e o c e r a t o d u s as their sister group. All lungfishes seem to be more closely related to tetrapods than the coelacanth is. This result appears to rule out the possibility that the coelacanth lineage gave rise to land vertebrates. The common ancestor of lungfishes and tetrapods might have possessed multiple morphological traits that are shared by lungfishes and tetrapods [Meyer and Wilson (1990) listed 14 such traits]. Those traits that seem to link L a t i m e r i a and tetrapods are arguably due to convergent evolution or reversals and not to common descent. In this way, the molecular tree facilitates an evolutionary interpretation of the morphological differences among the living forms. We recommended that the extinct groups of lobe-finned fishes be placed onto the molecular tree that has lungfishes and not the coelacanth more closely related to tetrapods. The placement of fossils would help to furOffprint requests to: Axel Meyer ther interpret the sequence of morphological events and innovations associated with the origin of tetrapods but appears to be problematic because the quality of fossils is not always high enough, and differences among paleontologists in the interpretation of the fossils have stood in the way of a consensus opinion for the branching order among lobefinned fishes. Marshall and Schultze (1992) criticized the morphological analysis presented by Meyer and Wilson (1990) and suggest that 13 of the 14 morphological traits that support the sister group relationship of lungfishes and tetrapods are not shared derived characters. Here we present further alternative viewpoints to the ones of Marshall and Schultze (1992) from the paleontological literature. We argue that all available information (paleontological, neontological, and molecular data) and rigorous cladistic methodology should be used when relating fossils and extant taxa in a phylogenetic framework. K e y w o r d s : Polymerase chain reaction --12S rRNA --Coelacanth --L a t i m e r i a c h a l u m n a e -- Ray-finned fishes --Lungfishes --L e p i d o s i r e n --Protopterus --N e o c e r a t o d u s ...

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“…However, it would certainly be an error to equate this idea with a general «paleon-tological method» (Henning, 1966, p. 140), which assumes, falsely, that a single methodological program exists. On the other band, methodological narrowness is evident in the way sorne cladists seem to be approaching the problem as, for example, in Patterson (1981).…”

Section: * * *mentioning

confidence: 99%

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confidence: 99%

Paraphyletic groups in phylogenetic analysis: Progymnospermopsida and Préphanérogames in alternative views of seed plant relationships

Stein

Beck

1987

Bulletin de la Société Botanique de France. Actualités Botaniqu

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Summary.-Prompted by Patterson's (1981) criticism of fossils, the notion of «paraphyletic group», often used by paleontologists in phylogenetic studies, is investigated here in a cladistic con· text. Two groups are treated in detail as explicit historical hypotheses : fossil Progymnospermopsida and living and fossil Préphanérogames. Farris's formai definition of paraphyly is adopted but irnplemented using named transitions in cladistic characters as delirniters of each group. In addition, it is suggested that a «candidate for ancestor» of each derived «outside» taxon be recognized within each hypothesis of paraphyly. Using this approach, the paraphyletic status of both Progymnospermopsida and Phréphanérogames is assessed under the phylogenetic views of Beek, Rothwell, Meyen, and Doyle and Donoghue. Although there are major differences in the «candidates for anceston, paraphyly is supported for the Progymnospermopsida in each case. Paraphyletic status for Préphanéro-games, however, is only possible under the Rothwell and Doyle and Donoghue phylogenetic view· points, and seems vulnerable to likely changes in the interpretation of certain Mesozoic «pterido-sperm» taxa as they become better known. Beyond simple cladistic description, however, there remains the question whether the Progymnospermopsida is an «objectively real» or «biologically meaningfub group. We suggest that the combination of features «typically gymnospermous secondary growth» and «pteridophytic reproduction» indicates an evolutionary significance for the group.

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Significance of Fossils in Determining Evolutionary Relationships

Cited by 277 publications

References 47 publications

Phylogeny Reconstruction: The Role of Morphology

Phylogeny Reconstruction: The Role of Morphology

Molecules, fossils, and the origin of tetrapods

Paraphyletic groups in phylogenetic analysis: Progymnospermopsida and Préphanérogames in alternative views of seed plant relationships

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