scholarly journals The inseparability of sampling and time and its influence on attempts to unify the molecular and fossil records

Paleobiology ◽  
2018 ◽  
Vol 44 (4) ◽  
pp. 561-574 ◽  
Author(s):  
Melanie J. Hopkins ◽  
David W. Bapst ◽  
Carl Simpson ◽  
Rachel C. M. Warnock
Keyword(s):  
Mathematical Models ◽  
Fossil Record ◽  
Evolutionary History ◽  
Molecular Data ◽  
The Other ◽  
Deep Time ◽  
Approaches To Studying ◽  
Data Source ◽  
Fossil Records ◽  
Estimate Uncertainty

AbstractThe two major approaches to studying macroevolution in deep time are the fossil record and reconstructed relationships among extant taxa from molecular data. Results based on one approach sometimes conflict with those based on the other, with inconsistencies often attributed to inherent flaws of one (or the other) data source. Any contradiction between the molecular and fossil records represents a failure of our ability to understand the imperfections of our data, as both are limited reflections of the same evolutionary history. We therefore need to develop conceptual and mathematical models that jointly explain our observations in both records. Fortunately, the different limitations of each record provide an opportunity to test or calibrate the other, and new methodological developments leverage both records simultaneously. However, we must reckon with the distinct relationships between sampling and time in the fossil record and molecular phylogenies. These differences impact our recognition of baselines and the analytical incorporation of age estimate uncertainty.

scholarly journals Discriminating signal from noise in the fossil record of early vertebrates reveals cryptic evolutionary history

2015 ◽  
Vol 282 (1800) ◽  
pp. 20142245 ◽  
Author(s):  
Robert S. Sansom ◽  
Emma Randle ◽  
Philip C. J. Donoghue
Keyword(s):  
Fossil Record ◽  
Evolutionary History ◽  
Biological Factors ◽  
Sea Level Changes ◽  
Upper Ordovician ◽  
Recovery Potential ◽  
Random Models ◽  
Rock Record ◽  
Early Vertebrates ◽  
Fossil Records

The fossil record of early vertebrates has been influential in elucidating the evolutionary assembly of the gnathostome bodyplan. Understanding of the timing and tempo of vertebrate innovations remains, however, mired in a literal reading of the fossil record. Early jawless vertebrates (ostracoderms) exhibit restriction to shallow-water environments. The distribution of their stratigraphic occurrences therefore reflects not only flux in diversity, but also secular variation in facies representation of the rock record. Using stratigraphic, phylogenetic and palaeoenvironmental data, we assessed the veracity of the fossil records of the jawless relatives of jawed vertebrates (Osteostraci, Galeaspida, Thelodonti, Heterostraci). Non-random models of fossil recovery potential using Palaeozoic sea-level changes were used to calculate confidence intervals of clade origins. These intervals extend the timescale for possible origins into the Upper Ordovician; these estimates ameliorate the long ghost lineages inferred for Osteostraci, Galeaspida and Heterostraci, given their known stratigraphic occurrences and stem–gnathostome phylogeny. Diversity changes through the Silurian and Devonian were found to lie within the expected limits predicted from estimates of fossil record quality indicating that it is geological, rather than biological factors, that are responsible for shifts in diversity. Environmental restriction also appears to belie ostracoderm extinction and demise rather than competition with jawed vertebrates.

scholarly journals Is evolutionary history repeatedly rewritten in light of new fossil discoveries?

2010 ◽  
Vol 278 (1705) ◽  
pp. 599-604 ◽  
Author(s):  
J. E. Tarver ◽  
P. C. J. Donoghue ◽  
M. J. Benton
Keyword(s):  
New Species ◽  
Mass Media ◽  
Fossil Record ◽  
Evolutionary History ◽  
Popular Science ◽  
Old World Monkeys ◽  
Catarrhine Primates ◽  
The Past ◽  
Fossil Records ◽  
Species Being

Mass media and popular science journals commonly report that new fossil discoveries have ‘rewritten evolutionary history’. Is this merely journalistic hyperbole or is our sampling of systematic diversity so limited that attempts to derive evolutionary history from these datasets are premature? We use two exemplars—catarrhine primates (Old World monkeys and apes) and non-avian dinosaurs—to investigate how the maturity of datasets can be assessed. Both groups have been intensively studied over the past 200 years and so should represent pinnacles in our knowledge of vertebrate systematic diversity. We test the maturity of these datasets by assessing the completeness of their fossil records, their susceptibility to changes in macroevolutionary hypotheses and the balance of their phylogenies through study time. Catarrhines have shown prolonged stability, with discoveries of new species being evenly distributed across the phylogeny, and thus have had little impact on our understanding of their fossil record, diversification and evolution. The reverse is true for dinosaurs, where the addition of new species has been non-random and, consequentially, their fossil record, tree shape and our understanding of their diversification is rapidly changing. The conclusions derived from these analyses are relevant more generally: the maturity of systematic datasets can and should be assessed before they are exploited to derive grand macroevolutionary hypotheses.

scholarly journals The oldest known fur seal

2015 ◽  
Vol 11 (2) ◽  
pp. 20140835 ◽  
Author(s):  
Robert W. Boessenecker ◽  
Morgan Churchill
Keyword(s):  
Fossil Record ◽  
Evolutionary History ◽  
Southern California ◽  
Middle Miocene ◽  
Sea Lions ◽  
Fur Seals ◽  
Fur Seal ◽  
Fossil Records ◽  
Phylogenetic Affinities

The poorly known fossil record of fur seals and sea lions (Otariidae) does not reflect their current diversity and widespread abundance. This limited fossil record contrasts with the more complete fossil records of other pinnipeds such as walruses (Odobenidae). The oldest known otariids appear 5–6 Ma after the earliest odobenids, and the remarkably derived craniodental morphology of otariids offers few clues to their early evolutionary history and phylogenetic affinities among pinnipeds. We report a new otariid, Eotaria crypta , from the lower middle Miocene ‘Topanga’ Formation (15–17.1 Ma) of southern California, represented by a partial mandible with well-preserved dentition. Eotaria crypta is geochronologically intermediate between ‘enaliarctine’ stem pinnipedimorphs (16.6–27 Ma) and previously described otariid fossils (7.3–12.5 Ma), as well as morphologically intermediate by retaining an M 2 and a reduced M 1 metaconid cusp and lacking P 2–4 metaconid cusps. Eotaria crypta eliminates the otariid ghost lineage and confirms that otariids evolved from an ‘enaliarctine’-like ancestor.

scholarly journals The oldest known fur seal

2017 ◽  
Author(s):  
Robert Boessenecker ◽  
Morgan Churchill
Keyword(s):  
Fossil Record ◽  
Evolutionary History ◽  
Southern California ◽  
Middle Miocene ◽  
Sea Lions ◽  
Fur Seals ◽  
Fur Seal ◽  
Fossil Records ◽  
Phylogenetic Affinities

The poorly known fossil record of fur seals and sea lions (Otariidae) does not reflect their current diversity and widespread abundance. This limited fossil record contrasts with the more complete fossil records of other pinnipeds such as walruses (Odobenidae). The oldest known otariids appear 5-6 Ma after the earliest odobenids, and the remarkably derived craniodental morphology of otariids offers few clues to their early evolutionary history and phylogenetic affinities among pinnipeds. We report a new otariid, Eotaria crypta, from the early middle Miocene “Topanga” Formation (15-17.5 Ma) of southern California, represented by a partial mandible with well-preserved dentition. Eotaria crypta is geochronologically intermediate between “enaliarctine” stem pinnipedimorphs (16.6-27 Ma) and previously described otariid fossils (7.3-12.5 Ma), as well as morphologically intermediate by retaining an M2 and a reduced M1 metaconid cusp and lacking P2-4 metaconid cusps. Eotaria crypta eliminates the otariid ghost lineage and confirms that otariids evolved from an “enaliarctine”-like ancestor.

scholarly journals Cretaceous amber fossils highlight the evolutionary history and morphological conservatism of land snails

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Takahiro Hirano ◽  
Kaito Asato ◽  
Shûhei Yamamoto ◽  
Yui Takahashi ◽  
Satoshi Chiba
Keyword(s):  
Evolutionary History ◽  
New Genus ◽  
Soft Tissues ◽  
Divergence Time ◽  
Land Snail ◽  
Molecular Data ◽  
Land Snails ◽  
Burmese Amber ◽  
Extant Species ◽  
Fossil Records

Abstract Other than hard bones and shells, it is rare for soft tissues to fossilize, but occasionally they are well-preserved in amber. Here, we focus on both modern and fossilized species of the land snail superfamily Cyclophoroidea. Phylogenetic relationships within the Cyclophoroidea were previously studied using extant species, but timing of divergence within the group remains unclear. In addition, it is difficult to observe morphological traits such as the chitinous operculum and periostracum of fossil snails due to their poor preservation potential. Here we describe nine species including a new genus and five new species of well-preserved fossil cyclophoroideans from the mid-Cretaceous Burmese amber. These fossils include not only the shell, but also the chitinous operculum and periostracum, soft body, and excrements. We present the first estimation of divergence time among cyclophoroidean families using fossil records and molecular data, suggesting extreme morphological conservatism of the Cyclophoroidea for nearly 100 million years.

Darwin's two competing phylogenetic trees: marsupials as ancestors or sister taxa?

2012 ◽  
Vol 39 (2) ◽  
pp. 217-233 ◽  
Author(s):  
J. David Archibald
Keyword(s):  
Fossil Record ◽  
Evolutionary Biology ◽  
Phylogenetic Trees ◽  
Charles Darwin ◽  
The Other ◽  
Charles Lyell ◽  
Single Origin ◽  
Molecular Studies ◽  
Richard Owen ◽  
First Time

Studies of the origin and diversification of major groups of plants and animals are contentious topics in current evolutionary biology. This includes the study of the timing and relationships of the two major clades of extant mammals – marsupials and placentals. Molecular studies concerned with marsupial and placental origin and diversification can be at odds with the fossil record. Such studies are, however, not a recent phenomenon. Over 150 years ago Charles Darwin weighed two alternative views on the origin of marsupials and placentals. Less than a year after the publication of On the origin of species, Darwin outlined these in a letter to Charles Lyell dated 23 September 1860. The letter concluded with two competing phylogenetic diagrams. One showed marsupials as ancestral to both living marsupials and placentals, whereas the other showed a non-marsupial, non-placental as being ancestral to both living marsupials and placentals. These two diagrams are published here for the first time. These are the only such competing phylogenetic diagrams that Darwin is known to have produced. In addition to examining the question of mammalian origins in this letter and in other manuscript notes discussed here, Darwin confronted the broader issue as to whether major groups of animals had a single origin (monophyly) or were the result of “continuous creation” as advocated for some groups by Richard Owen. Charles Lyell had held similar views to those of Owen, but it is clear from correspondence with Darwin that he was beginning to accept the idea of monophyly of major groups.

Kecakapan Hidup Abad Ke-21 dalam Tokoh Utama Dongeng Jawa Timur Kajian Antropologi Sastra

2020 ◽  
Vol 13 (2) ◽  
pp. 168
Author(s):  
Rian Damariswara
Keyword(s):  
Critical Thinking ◽  
21St Century ◽  
Fairy Tales ◽  
Life Skills ◽  
Fairy Tale ◽  
Good Life ◽  
The Other ◽  
Main Character ◽  
Data Source ◽  
Creativity And Innovation

ABSTRAKTokoh utama dalam dongeng Jawa Timur memiliki sisi lain yang perlu diungkap. Sisi lain tersebut, yakni kecakapan hidup yang dimiliki tokoh utama dalam menyelesaikan masalah yang dihadapinya. Kecakapan hidup tersebut, memiliki relevansi dengan kecakapan hidup di abad ke-21. Jadi, dengan menganalisis kecakapan hidup tokoh utama secara otomatis peneliti dan pembaca dapat mengetahui bahwa tokoh-tokoh dongeng yang terdapat di Jawa Timur memiliki budaya hidup yang baik untuk dijadikan contoh dan motivasi.Untuk mengungkap kecakapan hidup abad ke-21 pada tokoh utama dongeng Jawa Timur menggunakan kajian antropologi sastra.Penelitian ini termasuk deskriptif kualitatif. Sumber data adalah teks dongeng Jawa Timur. Teknik yang digunakan adalah studi dokumenter. Kecakapan hidup abad ke-21 yang ditemukan pada dongeng Jawa Timur sebagai berikut. Pertama, berpikir kritis dan pemecahan masalah. Semua tokoh utama dalam dongeng memiliki pemikiran kritis sehingga dapat memecahkan masalah. Kedua, kreativitas dan inovasi yang ditemukan yakni jenis pengembangan dan sintesis. Inovasi pengembangan yang ditemukan adalah adanya alat bajak sawah dari batu menjadi kayu dan ditarik sapi serta dapat dipergunakan sebagai sarana hiburan. Alat tersebut diberi nama karapan sapi.  Inovasi sintesis adalah menggabungkan segala sesuatu yang dimiliki untuk dijadikan sesuatu yang baru. Seperti pada dongeng Asal Mula Reog Ponorogo,yakni menggabungkan kepala tokoh Singabarong dengan burung merak sehingga dinamakan reog ponorogo. Ketiga, kolaborasi antaranggota dan pemimpin dengan bawahan. Keempat, komunikasi yakni berupa diskusi, pengarahan, berkeluh kesah, dan perintah.Kata kunci: Kecakapan hidup abad ke-21, Tokoh utama, DongengABSTRACTThe main character in the East Java fable has another side that needs to be revealed. The other side, namely the life skills possessed by the main character in solving the problems they face. Life skills, have relevance to 21st century life skills. Therefore, by analyzing the life skills of the main characters automatically the researcher and reader can find out that the fairy tale figures in East Java which have a good life culture to be used as an example and motivation. To uncover 21st century life skills in the main characters of the East Javanese fable, the study of literary anthropology is used. This research is descriptive qualitative. The data source is the text of a fairy tale in East Java. The technique used is documentary study. The 21st century life skills found in the East Java fable are as follows. First, critical thinking and problem solving. All the main characters in fairy tales have critical thinking so they can solve problems. Second, the creativity and innovation found are types of development and synthesis. Development innovation that was found was the existence of a rice plow from stone to wood and pulled by cows and could be used as a means of entertainment. The tool is named Karapan Sapi. Synthesis of innovation is to combine everything that is owned to be something new. As in the fable of Reog Ponorogo, which combines the head of the Singabarong character with a peacock so it is called Reog Ponorogo. Third, collaboration between members and leaders with subordinates. Fourth, communication in the form of discussion, direction, complaints, and orders.Keyword: 21st century life skills, The main character, Fairy tale

scholarly journals Consistency of causal claims in observational studies: a review of papers published in a general medical journal

BMJ Open ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. e043339
Author(s):  
Camila Olarte Parra ◽  
Lorenzo Bertizzolo ◽  
Sara Schroter ◽  
Agnès Dechartres ◽  
Els Goetghebeur
Keyword(s):  
Medical Journal ◽  
Observational Studies ◽  
The Other ◽  
Research Papers ◽  
General Medical Journal ◽  
Outcome Relationship ◽  
Causal Statement ◽  
Data Source ◽  
Published Research ◽  
Causal Language

ObjectiveTo evaluate the consistency of causal statements in observational studies published in The BMJ.DesignReview of observational studies published in a general medical journal.Data sourceCohort and other longitudinal studies describing an exposure-outcome relationship published in The BMJ in 2018. We also had access to the submitted papers and reviewer reports.Main outcome measuresProportion of published research papers with ‘inconsistent’ use of causal language. Papers where language was consistently causal or non-causal were classified as ‘consistently causal’ or ‘consistently not causal’, respectively. For the ‘inconsistent’ papers, we then compared the published and submitted version.ResultsOf 151 published research papers, 60 described eligible studies. Of these 60, we classified the causal language used as ‘consistently causal’ (48%), ‘inconsistent’ (20%) and ‘consistently not causal’(32%). Eleven out of 12 (92%) of the ‘inconsistent’ papers were already inconsistent on submission. The inconsistencies found in both submitted and published versions were mainly due to mismatches between objectives and conclusions. One section might be carefully phrased in terms of association while the other presented causal language. When identifying only an association, some authors jumped to recommending acting on the findings as if motivated by the evidence presented.ConclusionFurther guidance is necessary for authors on what constitutes a causal statement and how to justify or discuss assumptions involved. Based on screening these papers, we provide a list of expressions beyond the obvious ‘cause’ word which may inspire a useful more comprehensive compendium on causal language.

Integrative taxonomic and geographic variation analyses in Cyrtodactylus aequalis (Squamata: Gekkonidae) from southern Myanmar (Burma): one species, two different stories

2020 ◽  
Vol 66 (3-4) ◽  
pp. 151-179
Author(s):  
L. Lee Grismer ◽  
L. Wood Perry ◽  
Marta S. Grismer ◽  
Evan S.H. Quah ◽  
Myint Kyaw Thura ◽  
...  
Keyword(s):  
Geographic Variation ◽  
Evolutionary History ◽  
Phylogenetic Inference ◽  
Morphological Characters ◽  
Molecular Data ◽  
Biodiversity Crisis ◽  
Allopatric Populations ◽  
Compelling Argument ◽  
Historical Accuracy ◽  
Molecular Phylogenetic

The historical accuracy of building taxonomies is improved when they are based on phylogenetic inference (i.e., the resultant classifications are less apt to misrepresent evolutionary history). In fact, taxonomies inferred from statistically significant diagnostic morphological characters in the absence of phylogenetic considerations, can contain non-monophyletic lineages. This is especially true at the species level where small amounts of gene flow may not preclude the evolution of localized adaptions in different geographic areas while underpinning the paraphyletic nature of each population with respect to the other. We illustrate this point by examining genetic and morphological variation among three putatively allopatric populations of the granite-dwelling Bent-toed Gecko Cyrtodactylus aequalis from hilly regions in southeastern Myanmar. In the absence of molecular phylogenetic inference, a compelling argument for three morphologically diagnosable species could be marshaled. However, when basing the morphological analyses of geographic variation on a molecular phylogeny, there is a more compelling argument that only one species should be recognized. We are cognizant of the fact however, that when dealing with rare species or specimens for which no molecular data are possible, judicious morphological analyses are the only option—and the desired option given the current worldwide biodiversity crisis.

scholarly journals A 100‐Million‐Year Gap in the Knowledge of the Evolutionary History of Bromeliaceae: A Brief Review of Fossil Records

2021 ◽  
Author(s):  
Igor Musauer Kessous ◽  
Beatriz Neves ◽  
Fabiano Salgueiro ◽  
Andrea Ferreira Costa
Keyword(s):  
Evolutionary History ◽  
History Of ◽  
Fossil Records
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