Cretaceous eutherians and Laurasian origin for placental mammals near the K/T boundary

Wible, John R.; Rougier, Guillermo W.; Novacek, Michael J.; Asher, Robert J.

doi:10.1038/nature05854

Cited by 271 publications

(277 citation statements)

References 22 publications

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“…We created the most taxon-rich morphological character matrix of Eutheria ( plus six outgroup taxa; see above) currently available by combining matrices from five existing studies [8,11,40 -42], which represent differently modified versions of a previously published matrix focused on eutherian relationships [7] (see the electronic supplementary material, §1, for details). The final matrix comprises 102 taxa and 421 characters.…”

Section: (B) Morphological Character Matrixmentioning

confidence: 99%

“…The timing of the origin and early diversification of placentals has been the focus of intensive research, yet remains controversial [1][2][3][4][5]. Palaeontological studies typically place the origin and early diversification of Placentalia at, or at most slightly before, the Cretaceous-Palaeogene (K-Pg) boundary at 66 Ma [2,[6][7][8]. This conclusion is based on the age of oldest known definitive placentals, all of which are Palaeocene or younger [1,2,[6][7][8].…”

Section: Introductionmentioning

confidence: 99%

“…Obviously, the discovery of a single unequivocal placental fossil prior to the K-Pg boundary would overturn the strict 'explosive' model. However, despite intensive collecting and enormous improvements in our knowledge of Mesozoic mammals in recent years [11][12][13], definitive pre-Palaeocene placentals have still not been identified [2,7,8,14]; a few putative Mesozoic records of placentals have been reported, but they are from the latest Cretaceous [15,16], and they remain controversial [2,16,17].…”

Section: Introductionmentioning

confidence: 99%

“…Palaeontological studies typically place the origin and early diversification of Placentalia at, or at most slightly before, the Cretaceous-Palaeogene (K-Pg) boundary at 66 Ma [2,[6][7][8]. This conclusion is based on the age of oldest known definitive placentals, all of which are Palaeocene or younger [1,2,[6][7][8]. This palaeontological evidence is the basis for the 'explosive' model of placental origins [9], which proposes that Placentalia diversified from a single lineage in the aftermath of the K-Pg mass extinction event [10].…”

Section: Introductionmentioning

confidence: 99%

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Ancient dates or accelerated rates? Morphological clocks and the antiquity of placental mammals

2014

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Analyses of a comprehensive morphological character matrix of mammals using 'relaxed' clock models (which simultaneously estimate topology, divergence dates and evolutionary rates), either alone or in combination with an 8.5 kb nuclear sequence dataset, retrieve implausibly ancient, Late JurassicEarly Cretaceous estimates for the initial diversification of Placentalia (crown-group Eutheria). These dates are much older than all recent molecular and palaeontological estimates. They are recovered using two very different clock models, and regardless of whether the tree topology is freely estimated or constrained using scaffolds to match the current consensus placental phylogeny. This raises the possibility that divergence dates have been overestimated in previous analyses that have applied such clock models to morphological and total evidence datasets. Enforcing additional age constraints on selected internal divergences results in only a slight reduction of the age of Placentalia. Constraining Placentalia to less than 93.8 Ma, congruent with recent molecular estimates, does not require major changes in morphological or molecular evolutionary rates. Even constraining Placentalia to less than 66 Ma to match the 'explosive' palaeontological model results in only a 10-to 20-fold increase in maximum evolutionary rate for morphology, and fivefold for molecules. The large discrepancies between clock-and fossil-based estimates for divergence dates might therefore be attributable to relatively small changes in evolutionary rates through time, although other explanations (such as overly simplistic models of morphological evolution) need to be investigated. Conversely, dates inferred using relaxed clock models (especially with discrete morphological data and MRBAYES) should be treated cautiously, as relatively minor deviations in rate patterns can generate large effects on estimated divergence dates.

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Section: (B) Morphological Character Matrixmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Ancient dates or accelerated rates? Morphological clocks and the antiquity of placental mammals

2014

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“…They have been described as stem Placentalia or alternatively are allied to certain crown Placentalia such as Afrotheria, Lipotyphla, Primates, Tupaiidae, and even Lagomorpha (e.g., Leidy 1868;Matthew 1909;Gregory 1910;Simpson 1945;McKenna 1966McKenna , 1975Szalay 1966Szalay , 1977Butler 1972Butler , 1988Novacek 1986;MacPhee and Novacek 1993;Asher 1999;Asher et al 2002Asher et al , 2003Rose 2006a;Wible et al 2007Wible et al , 2009. Recently, a comprehensive study based on morphological data from fossil and extant mammals combined with molecular sequences suggests a sister-group relationship of Leptictida and Macroscelidea, with both nested within Afrotheria (O'Leary et al 2013).…”

Section: Introductionmentioning

confidence: 99%

Digital reconstruction of the inner ear of Leptictidium auderiense (Leptictida, Mammalia) and North American leptictids reveals new insight into leptictidan locomotor agility

et al. 2016

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Mammalian Phylogeny

Phillips¹,

Penny²

2010

Encyclopedia of Life Sciences

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Living mammals can be divided into three subclasses (monotremes, marsupials and placentals) and within these, about 27 orders. Final resolution of the relationships between the orders is only now being achieved with the increased availability of deoxyribonucleic acid (DNA) sequences. Highlights include the deep division of placental mammals into African (Afrotheria), South American (Xenarthra) and northern hemisphere (Boreoeutheria) super‐orders, and the finding that the once considered primitive ‘Insectivora’ and ‘Edentata’ clades, in fact, have members distributed widely among these super‐orders. Another surprise finding from DNA studies has been that whale origins lie among the even‐toed ungulates (Artiodactyla). Our order, Primates is most closely related to the flying lemurs and next, the tree shrews. With the mammal phylogeny becoming well resolved, it is increasingly being used as a framework for inferring evolutionary and ecological processes, such as adaptive radiation. Key Concepts: A phylogeny describes the relationships of organisms with respect to their shared ancestry. In the context of phylogenetics, molecular data refer to the genotype (DNA) and its direct translations (e.g. protein sequences). Morphology refers to an organism's structural phenotype, sometimes limited to anatomy, but often also incorporating physiology. Homoplasy describes character states that are similar for reasons other than shared ancestry, such as due to convergent or parallel evolution. Retroposons are DNA sequences that can use the protein, reverse transcriptase to copy themselves and insert into new positions in the genome. Molecular dating employs DNA or protein sequence differences between organisms to provide evolutionary time scales, with independent (especially fossil) information used to convert molecular differences into time. Adaptive radiation describes the (often) rapid diversification of closely related species into a wide variety of ecological niches.

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Cretaceous eutherians and Laurasian origin for placental mammals near the K/T boundary

Cited by 271 publications

References 22 publications

Ancient dates or accelerated rates? Morphological clocks and the antiquity of placental mammals

Ancient dates or accelerated rates? Morphological clocks and the antiquity of placental mammals

Digital reconstruction of the inner ear of Leptictidium auderiense (Leptictida, Mammalia) and North American leptictids reveals new insight into leptictidan locomotor agility

Mammalian Phylogeny

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