scholarly journals Estimating the age of poorly dated fossil specimens and deposits using a total-evidence approach and the fossilized birth-death process

2021 ◽  
Author(s):  
Joelle Barido-Sottani ◽  
Dagmara Zyla ◽  
Tracy A. Heath

Bayesian total-evidence approaches under the fossilized birth-death model enable biologists to combine fossil and extant data---while accounting for uncertainty in the ages of fossil specimens---in an integrative phylogenetic analysis. Fossil age uncertainty is a key feature of the fossil record as many empirical datasets may contain a mix of precisely dated and poorly dated fossil specimens or deposits. In this study, we explore whether reliable age estimates for fossil specimens can be obtained from Bayesian total-evidence phylogenetic analyses under the fossilized birth-death model. Through simulations based on the example of the Baltic amber deposit, we show that estimates of fossil ages obtained through such an analysis are accurate, particularly when the proportion of poorly dated specimens remains low and the majority of fossil specimens have precise dates. We confirm our results using an empirical dataset of living and fossil penguins by artificially increasing the age uncertainty around some fossil specimens and showing that the resulting age estimates overlap with the recorded age ranges. Our results are applicable to many empirical datasets where classical methods of establishing fossil ages have failed, such as the Baltic amber and the Gobi Desert deposits.

2018 ◽  
Vol 49 (4) ◽  
pp. 399-408
Author(s):  
Sara Gamboa ◽  
Vicente M. Ortuño

Limodromus emetikos sp. n. (Coleoptera: Carabidae) is described and illustrated from Baltic amber (Eocene). Based on its morphological features, the new species is considered a sister taxon of the extant Holarctic assimilis species group. Furthermore, the specimen described here could represent a case of stress-triggered regurgitation, which would represent the first fossil record of such a process in beetles.


Zootaxa ◽  
2002 ◽  
Vol 96 (1) ◽  
pp. 1 ◽  
Author(s):  
OLIVIER BÉTHOUX ◽  
ANDRÉ NEL

After the revision of several fossils and observations of recent taxa, we propose a new interpretation of the wing venation pattern for the ‘orthopteroid lineage’. The Orthoptera and several taxa previously assigned to the paraphyletic group ‘Protorthoptera’ are included in a common clade, Archaeorthoptera taxon nov. The Orthoptera and some closest relative groups are included in the Panorthoptera sensu nov. These assignments are based on new autapomorphies based on venation patterns. A cladistic phylogenetic analysis of the Orthoptera is performed for the first time on the fossil record of this group, based on 74 characters (131 informative states). Three taxa assigned to the Archaeorthoptera nec Panorthoptera compose the outgroup. The ingroup is composed of three Panorthoptera nec Orthoptera and 63 Orthoptera, mainly from the Palaeozoic and Mesozoic. Following this initial phylogeny, we propose several nomenclatural changes; the Ensifera are redefined and the relationships between Caelifera and Ensifera sensu nov., and those between the major clades of modern Ensifera sensu nov., are clarified. Relationships within the ‘oedischioid’ stem-group remain unclear. The evolution of the venational structures within the Orthoptera is discussed and in this analysis the Orthoptera were not clearly affected by the Permo-Triassic biodiversity “crisis”. The capacity of the fossil taxa to be used in phylogenetic analyses is discussed, using the example of the ‘orthopteroid’ insects.


2011 ◽  
Vol 278 (1719) ◽  
pp. 2791-2797 ◽  
Author(s):  
Guillaume Billet ◽  
Lionel Hautier ◽  
Christian de Muizon ◽  
Xavier Valentin

The cingulates of the mammalian order Xenarthra present a typical case of disagreement between molecular and morphological phylogenetic studies. We report here the discovery of two new skulls from the Late Oligocene Salla Beds of Bolivia (approx. 26 Ma), which are the oldest known well-preserved cranial remains of the group. A new taxon is described: Kuntinaru boliviensis gen. et sp. nov. A phylogenetic analysis clusters K. boliviensis together with the armadillo subfamily Tolypeutinae. These skulls document an early spotty occurrence for the Tolypeutinae at 26 Ma, in agreement with the temporal predictions of previous molecular studies. The fossil record of tolypeutines is now characterized by a unique occurrence in the Late Oligocene, and a subsequent 12 Myr lack in the fossil record. It is noteworthy that the tolypeutines remain decidedly marginal in the Late Palaeogene and Early Neogene deposits, whereas other cingulate groups diversify. Also, the anatomical phylogenetic analysis herein, which includes K. boliviensis , is congruent with recent molecular phylogenetic analyses. Kuntinaru boliviensis is the oldest confident calibration point available for the whole Cingulata.


Fossil Record ◽  
2014 ◽  
Vol 18 (1) ◽  
pp. 37-42 ◽  
Author(s):  
P. G. Mitov ◽  
J. A. Dunlop ◽  
D. Penney

Abstract. A new specimen of Lacinius Thorell, 1876; (Opiliones: Phalangiidae) from Eocene Baltic amber is described. We interpret it as conspecific with a slightly younger record from the German Bitterfeld amber, originally referred to as the extant species L. erinaceus Staręga, 1966. Our new specimen reveals pedipalpal apophyses on both the patella and the tibia, features which we can now confirm in the Bitterfeld fossil too. This unique character combination for the genus justifies a new, extinct species: Lacinius bizleyi sp. nov. The Baltic amber inclusion dates to ca. 44–49 Ma, and is thus the oldest putative example of Lacinius in the fossil record. It is a further example of an arachnid species shared between Baltic and Bitterfeld amber.


2021 ◽  
Author(s):  
Brendon E Boudinot ◽  
Marek L Borowiec ◽  
Matthew M Prebus

Within the Formicidae, the higher classification of nearly all subfamilies has been recently revised due to the findings of molecular phylogenetics. Here, we integrate morphology and molecular data to holistically address the evolution and classification of the ant genus Lasius, its tribe Lasiini, and their subfamily Formicinae. We accomplish this through a critical re-examination of morphology of extant and fossil taxa, molecular phylogenetic analyses, total-evidence dating under fossilized birth-death process, phylogeography, and ancestral state estimation. We use these results to provide revised taxonomic definitions for the Lasiini and select genera, and we provide a key to the genera of the Lasiini with emphasis on the Lasius genus group. We find that the crown Lasiini originated around the end of the Cretaceous on the Eurasian continent and is divisible into four morphologically distinct clades: Cladomyrma, the Lasius genus group, the Prenolepis genus group, and a previously undetected lineage we name XXXgen. n. The crown of the Lasius genus group is considerably younger than that of the Prenolepis genus group, indicating that extinction has played a major role in the evolution of the former clade. Lasius itself is divided into two well-supported monophyletic groups which are approximately equally speciose. We present evidence that temporary social parasitism and fungiculture arose in Lasius two times independently. Additionally, we recover the paraphyly of three Lasius subgenera and propose replacing all subgenera with an informal species group classification: Lasius = Acanthomyopssyn. rev., = Austrolasiussyn. n., = Cautolasiussyn. n., = Chthonolasius vsyn. n., = Dendrolasiussyn. n. Total-evidence analysis reveals that the Baltic-region amber fossil species Lasius pumilus and Pseudolasius boreus are misplaced to genus; we therefore designate XXXgen. n. for the former and XXXgen. n. for the latter. Further, we transfer XXX and Glaphyromyrmex out of the tribe, considering the former to be incertae sedis in the subfamily, and the latter a member of the Formicini (tribal transfer). Two final taxonomic actions are deemed necessary: synonymy of Lasius escamole Reza, 1925 with Liometopum apiculatum Mayr, 1870 syn. n. (subfamilial transfer), and transfer of Paratrechina kohli to Anoplolepis (tribal transfer, forming A. kohli (Forel, 1916) n. comb.).


2014 ◽  
Vol 112 (1) ◽  
pp. 190-195 ◽  
Author(s):  
Eva-Maria Sadowski ◽  
Leyla J. Seyfullah ◽  
Friederike Sadowski ◽  
Andreas Fleischmann ◽  
Hermann Behling ◽  
...  

The fossil record of carnivorous plants is very scarce and macrofossil evidence has been restricted to seeds of the extant aquatic genus Aldrovanda of the Droseraceae family. No case of carnivorous plant traps has so far been reported from the fossil record. Here, we present two angiosperm leaves enclosed in a piece of Eocene Baltic amber that share relevant morphological features with extant Roridulaceae, a carnivorous plant family that is today endemic to the Cape flora of South Africa. Modern Roridula species are unique among carnivorous plants as they digest prey in a complex mutualistic association in which the prey-derived nutrient uptake depends on heteropteran insects. As in extant Roridula, the fossil leaves possess two types of plant trichomes, including unicellular hairs and five size classes of multicellular stalked glands (or tentacles) with an apical pore. The apices of the narrow and perfectly tapered fossil leaves end in a single tentacle, as in both modern Roridula species. The glandular hairs of the fossils are restricted to the leaf margins and to the abaxial lamina, as in extant Roridula gorgonias. Our discovery supports current molecular age estimates for Roridulaceae and suggests a wide Eocene distribution of roridulid plants.


2016 ◽  
Author(s):  
Michael Matschiner ◽  
Zuzana Musilová ◽  
Julia M I Barth ◽  
Zuzana Starostová ◽  
Walter Salzburger ◽  
...  

Divergence-time estimation based on molecular phylogenies and the fossil record has provided insights into fundamental questions of evolutionary biology. In Bayesian node dating, phylogenies are commonly time calibrated through the specification of calibration densities on nodes representing clades with known fossil occurrences. Unfortunately, the optimal shape of these calibration densities is usually unknown and they are therefore often chosen arbitrarily, which directly impacts the reliability of the resulting age estimates. As possible solutions to this problem, two non-exclusive alternative approaches have recently been developed, the "fossilized birth-death" model and "total-evidence dating". While these approaches have been shown to perform well under certain conditions, they require including all (or a random subset) of the fossils of each clade in the analysis, rather than just relying on the oldest fossils of clades. In addition, both approaches assume that fossil records of different clades in the phylogeny are all the product of the same underlying fossil sampling rate, even though this rate has been shown to differ strongly between higher-level taxa. We here develop a flexible new approach to Bayesian node dating that combines advantages of traditional node dating and the fossilized birth-death model. In our new approach, calibration densities are defined on the basis of first fossil occurrences and sampling rate estimates that can be specified separately for all clades. We verify our approach with a large number of simulated datasets, and compare its performance to that of the fossilized birth death model. We find that our approach produces reliable age estimates that are robust to model violation, on par with the fossilized birth-death model. By applying our approach to a large dataset including sequence data from over 1000 species of teleost fishes as well as 147 carefully selected fossil constraints, we recover a timeline of teleost diversification that is incompatible with previously assumed vicariant divergences of freshwater fishes. Our results instead provide strong evidence for trans-oceanic dispersal of cichlids and other groups of teleost fishes.


2020 ◽  
Vol 3 (1) ◽  
pp. 068-075
Author(s):  
VALÉRIE NGÔ-MULLER ◽  
ANDRÉ NEL

Syrphid flies are an important clade of pollinators, and predators on several insect groups. The oldest record of its stem lineage is late Cretaceous, but this family really diversified during the Eocene-Oligocene, with a rather sparse fossil record. Here we describe from the Baltic amber the new genus and species Eoxanthandrus garroustei gen. et sp. nov., the first fossil representative of the Syrphinae ‘group’ Bacchini and Melanostomini. Its closest extant relatives prey on caterpillars, while the other Syrphinae generally prey on Hemiptera. This specialized biology possibly dates back to the middle Eocene.


PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9604
Author(s):  
Matthew G. Baron

The pterosaurs first appear in the fossil record in the middle of the Late Triassic. Their earliest representatives are known from Northern Hemisphere localities but, by the end of the Jurassic Period, this clade of flying reptiles achieved a global distribution, as well as high levels of diversity and disparity. Our understanding of early pterosaur evolution and the fundamental interrelationships within Pterosauria has improved dramatically in recent decades. However, there is still debate about how the various pterosaur subgroups relate to one another and about which taxa comprise these. Many recent phylogenetic analyses, while sampling well from among the known Triassic and Early Jurassic pterosaurs, have not included many non-pterosaurian ornithodirans or other avemetatarsalians. Given the close relationship between these groups of archosaurs, the omission of other ornithodirans and avemetatarsalians has the potential to adversely affect the results of phylogenetic analyses, in terms of character optimisation and ingroup relationships recovered. This study has addressed this issue and tests the relationships between the early diverging pterosaur taxa following the addition of avemetatarsalian taxa and anatomical characters to an existing early pterosaur dataset. This study has, for the first time, included taxa that represent the aphanosaurs, lagerpetids, silesaurids and dinosaurs, in addition to early pterosaurs. Anatomical characters used in other recent studies of archosaurs and early dinosaurs have also been incorporated. By expanding the outgroup taxa and anatomical character coverage in this pterosaur dataset, better resolution between the taxa within certain early pterosaur subclades has been achieved and stronger support for some existing clades has been found; other purported clades of early pterosaurs have not been found in this analysis—for example there is no support for a monophyletic Eopterosauria or Eudimorphodontidae. Further support has been found for a sister-taxon relationship between Peteinosaurus zambelli and Macronychoptera, a clade here named Zambellisauria (clade nov.), as well as for a monophyletic and early diverging Preondactylia. Some analyses also support the existence of a clade that falls as sister-taxon to the zambellisaurs, here named Caviramidae (clade nov.). Furthermore, some support has been found for a monophyletic Austriadraconidae at the base of Pterosauria. Somewhat surprisingly, Lagerpetidae is recovered outside of Ornithodira sensu stricto, meaning that, based upon current definitions at least, pterosaurs fall within Dinosauromorpha in this analysis. However, fundamental ornithodiran interrelationships were not the focus of this study and this particular result should be treated with caution for now. However, these results do further highlight the need for broader taxon and character sampling in phylogenetic analyses, and the effects of outgroup choice on determining ingroup relationships.


2021 ◽  
Author(s):  
Noah Meier ◽  
Anina Wacker ◽  
Seraina Klopfstein

Darwin wasps (Ichneumonidae) are one of the most species-rich insect families, but also one of the most understudied ones, both in terms of their extant and extinct diversity. We here use morphometrics of wing veins and an integrative Bayesian analysis to place a new rock fossil species from the Danish Fur Formation (~54 Ma) in the tree of Darwin wasps. The new species, Pherhombus parvulus n. sp., is placed firmly in Pherhombinae, an extinct subfamily so far only known from Baltic and Rovno-Ukranian ambers, which are estimated to be 34-48 Ma and 34-38 Ma, respectively. Our phylogenetic analysis recovers a subfamily clade within the higher Ophioniformes formed by Pherhombinae, Townesitinae and Hybrizontinae, in accordance with previous suggestions. Due to the placement of the new species as sister to the remaining members of Pherhombinae, we argue that our finding is not at odds with a much younger, late Eocene age (~34-41 Ma) of Baltic amber and instead demonstrates that Pherhombus existed over a much longer period than previously thought. Our results also exemplify the power of wing vein morphometrics and integrative phylogenetic analyses in resolving the placement even of poorly preserved fossil specimens.


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