Limits...
Closing the gap between rocks and clocks using total-evidence dating.

Ronquist F, Lartillot N, Phillips MJ - Philos. Trans. R. Soc. Lond., B, Biol. Sci. (2016)

Bottom Line: Failure to account for diversified sampling results in dramatic DRA, but this can be addressed using existing techniques.The major reason seems to be that current models do not account for dependencies among morphological characters, causing distorted topology and branch length estimates.Finally, diversification and fossil sampling priors that do not incorporate all the available background information can contribute to DRA, but these priors can also be used to compensate for DRA.

View Article: PubMed Central - PubMed

Affiliation: Department of Bioinformatics and Genetics, Swedish Museum of Natural History, PO Box 50007, 104 05 Stockholm, Sweden fredrik.ronquist@nrm.se.

No MeSH data available.


Related in: MedlinePlus

Inferred phylogenetic affinities of fossils. Despite the plasticity in the morphological data and/or the imperfection of our models of morphological evolution, the placements of fossils suggested by total-evidence analyses largely agree with the views expressed by palaeontologists (see text for more detailed discussion). Results are shown for the model assuming rapid diversification, but fossil placements were similar for other informative priors on the diversification and fossil sampling processes.
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RSTB20150136F8: Inferred phylogenetic affinities of fossils. Despite the plasticity in the morphological data and/or the imperfection of our models of morphological evolution, the placements of fossils suggested by total-evidence analyses largely agree with the views expressed by palaeontologists (see text for more detailed discussion). Results are shown for the model assuming rapid diversification, but fossil placements were similar for other informative priors on the diversification and fossil sampling processes.

Mentions: Under a total-evidence analysis, some fossils float around in the tree while the rich morphological data succeed in placing many others with considerable certainty (figure 8). Most of the fossil placements are quite consistent with palaeontological interpretations of the fossil record. The more notable exceptions include a monophyletic grouping of ‘condylarths’ usually thought of as paraphyletically or polyphyletically distributed in the tree, from presumed basal or stem placentals (Protungulatum) to South American (Didolodus, Protolipterna) and Northern Hemisphere (Hyopsodus, Phenacodus, Apheliscus) relatives of afrotherian or laurasiatherian ungulates. Another pair of presumed ungulate fossils (Thomashuxleya, Carodnia) are attracted towards basal Afrotheria lineages (the same effect is seen in O'Leary et al. [8]). Furthermore, three fossils that are usually considered to be crown or stem cetaceans [30], Rhodocetus, Artiocetus and Basilosaurus, are pulled deeper down into the tree in our analysis, forming a group of stem artiodactyls together with Mesonyx, a traditional mesonychid sister taxon to cetaceans. Most other fossil placements would seem to be in line with expectations. Leptictis, for example, is sister to crown placentals, which is more consistent with the traditional view that its closest affinities are with Late Cretaceous eutherians, such as Gypsonictos [31]. However, it seems that the large number of cranial and dental characters in the dataset might have resulted in the grouping of Mesonyx with fossil cetaceans, which is contradicted by major basicranial and ankle character complexes.Figure 8.


Closing the gap between rocks and clocks using total-evidence dating.

Ronquist F, Lartillot N, Phillips MJ - Philos. Trans. R. Soc. Lond., B, Biol. Sci. (2016)

Inferred phylogenetic affinities of fossils. Despite the plasticity in the morphological data and/or the imperfection of our models of morphological evolution, the placements of fossils suggested by total-evidence analyses largely agree with the views expressed by palaeontologists (see text for more detailed discussion). Results are shown for the model assuming rapid diversification, but fossil placements were similar for other informative priors on the diversification and fossil sampling processes.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4920337&req=5

RSTB20150136F8: Inferred phylogenetic affinities of fossils. Despite the plasticity in the morphological data and/or the imperfection of our models of morphological evolution, the placements of fossils suggested by total-evidence analyses largely agree with the views expressed by palaeontologists (see text for more detailed discussion). Results are shown for the model assuming rapid diversification, but fossil placements were similar for other informative priors on the diversification and fossil sampling processes.
Mentions: Under a total-evidence analysis, some fossils float around in the tree while the rich morphological data succeed in placing many others with considerable certainty (figure 8). Most of the fossil placements are quite consistent with palaeontological interpretations of the fossil record. The more notable exceptions include a monophyletic grouping of ‘condylarths’ usually thought of as paraphyletically or polyphyletically distributed in the tree, from presumed basal or stem placentals (Protungulatum) to South American (Didolodus, Protolipterna) and Northern Hemisphere (Hyopsodus, Phenacodus, Apheliscus) relatives of afrotherian or laurasiatherian ungulates. Another pair of presumed ungulate fossils (Thomashuxleya, Carodnia) are attracted towards basal Afrotheria lineages (the same effect is seen in O'Leary et al. [8]). Furthermore, three fossils that are usually considered to be crown or stem cetaceans [30], Rhodocetus, Artiocetus and Basilosaurus, are pulled deeper down into the tree in our analysis, forming a group of stem artiodactyls together with Mesonyx, a traditional mesonychid sister taxon to cetaceans. Most other fossil placements would seem to be in line with expectations. Leptictis, for example, is sister to crown placentals, which is more consistent with the traditional view that its closest affinities are with Late Cretaceous eutherians, such as Gypsonictos [31]. However, it seems that the large number of cranial and dental characters in the dataset might have resulted in the grouping of Mesonyx with fossil cetaceans, which is contradicted by major basicranial and ankle character complexes.Figure 8.

Bottom Line: Failure to account for diversified sampling results in dramatic DRA, but this can be addressed using existing techniques.The major reason seems to be that current models do not account for dependencies among morphological characters, causing distorted topology and branch length estimates.Finally, diversification and fossil sampling priors that do not incorporate all the available background information can contribute to DRA, but these priors can also be used to compensate for DRA.

View Article: PubMed Central - PubMed

Affiliation: Department of Bioinformatics and Genetics, Swedish Museum of Natural History, PO Box 50007, 104 05 Stockholm, Sweden fredrik.ronquist@nrm.se.

No MeSH data available.


Related in: MedlinePlus