History is written by the victors: The effect of the push of the past on the fossil record

When one hears the term “ground cover,” one immediately thinks of “grasses.” This perception is so deep-seated that paleobotanists even have been overheard to proclaim that “there was no ground cover before grasses.” Today grasses are so predominant in many environments that this perception is perpetuated easily. On the other hand, it is difficult to imagine the absence or lack of ground cover prior to the mid-Tertiary. We tested the hypothesis that different forms of ground cover existed in the past against examples from the Recent and the fossil record (Table 1). The Recent data were obtained from a large number of sources including those in the ecological, horticultural, and microbiological literature. Other data were derived from our knowledge of Precambrian life, sedimentology and paleosols, and the plant fossil record, especially in situ floras and fossil “monocultures.” Some of the data are original observations, but many others are from the literature. A detailed account of these results will be presented elsewhere (Pfefferkorn and LePage, in preparation).

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The fossil record of whip spiders: the past of Amblypygi

PalZ ◽

10.1007/s12542-021-00552-z ◽

2021 ◽

Author(s):

Carolin Haug ◽

Joachim T. Haug

Keyword(s):

Fossil Record ◽

3D Imaging ◽

Three Dimensional ◽

Dorsal Shield ◽

Stereo Images ◽

Geological Time ◽

High Quality ◽

The Past ◽

Over Time

AbstractWhip spiders (Amblypygi), as their name suggests, resemble spiders (Araneae) in some aspects, but differ from them by their heart-shaped (prosomal) dorsal shield, their prominent grasping pedipalps, and their subsequent elongate pair of feeler appendages. The oldest possible occurrences of whip spiders, represented by cuticle fragments, date back to the Devonian (c. 385 mya), but (almost) complete fossils are known from the Carboniferous (c. 300 mya) onwards. The fossils include specimens preserved on slabs or in nodules (Carboniferous, Cretaceous) as well as specimens preserved in amber (Cretaceous, Eocene, Miocene). We review here all fossil whip spider specimens, figure most of them as interpretative drawings or with high-quality photographs including 3D imaging (stereo images) to make the three-dimensional relief of the specimens visible. Furthermore, we amend the list by two new specimens (resulting in 37 in total). The fossil specimens as well as modern whip spiders were measured to analyse possible changes in morphology over time. In general, the shield appears to have become relatively broader and the pedipalps and walking appendages have become more elongate over geological time. The morphological details are discussed in an evolutionary framework and in comparison with results from earlier studies.

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Dental tissue proportions in fossil orangutans from mainland Asia and Indonesia

Human Origins Research ◽

10.4081/hor.2011.3 ◽

2011 ◽

Vol 1 (1) ◽

pp. e1 ◽

Cited By ~ 18

Author(s):

Tanya M. Smith ◽

Anne-Marie Bacon ◽

Fabrice Demeter ◽

Ottmar Kullmer ◽

Kim Thuy Nguyen ◽

...

Keyword(s):

Fossil Record ◽

Homo Sapiens ◽

Homo Erectus ◽

Dental Tissue ◽

Developmental Constraints ◽

Enamel Thickness ◽

Selective Pressures ◽

The Past ◽

Geometric Scaling ◽

Dental Reduction

Orangutans (Pongo) are the only great ape genus with a substantial Pleistocene and Holocene fossil record, demonstrating a much larger geographic range than extant populations. In addition to having an extensive fossil record, Pongo shows several convergent morphological similarities with Homo, including a trend of dental reduction during the past million years. While studies have documented variation in dental tissue proportions among species of Homo, little is known about variation in enamel thickness within fossil orangutans. Here we assess dental tissue proportions, including conventional enamel thickness indices, in a large sample of fossil orangutan postcanine teeth from mainland Asia and Indonesia. We find few differences between regions, except for significantly lower average enamel thickness (AET) values in Indonesian mandibular first molars. Differences between fossil and extant orangutans are more marked, with fossil Pongo showing higher AET in most postcanine teeth. These differences are significant for maxillary and mandibular first molars. Fossil orangutans show higher AET than extant Pongo due to greater enamel cap areas, which exceed increases in enamel-dentine junction length (due to geometric scaling of areas and lengths for the AET index calculation). We also find greater dentine areas in fossil orangutans, but relative enamel thickness indices do not differ between fossil and extant taxa. When changes in dental tissue proportions between fossil and extant orangutans are compared with fossil and recent Homo sapiens, Pongo appears to show isometric reduction in enamel and dentine, while crown reduction in H. sapiens appears to be due to preferential loss of dentine. Disparate selective pressures or developmental constraints may underlie these patterns. Finally, the finding of moderately thick molar enamel in fossil orangutans may represent an additional convergent dental similarity with Homo erectus, complicating attempts to distinguish these taxa in mixed Asian faunas.

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Bivalve systematics during the 20th century

Journal of Paleontology ◽

10.1017/s0022336000017170 ◽

2001 ◽

Vol 75 (6) ◽

pp. 1119-1127 ◽

Cited By ~ 7

Author(s):

Jay A. Schneider

Keyword(s):

20Th Century ◽

Molecular Systematics ◽

Fossil Record ◽

Evolutionary Biology ◽

The Past ◽

Invertebrate Paleontology

Over the past 75 years, the higher-level taxonomy of bivalves has received less attention than that of their fellow molluscs, gastropods. The publication of the bivalve volumes of the Treatise on Invertebrate Paleontology in 1969 was not followed by an explosion of study into the evolution of bivalves; rather, with only one or two exceptions, bivalve workers were noticeably absent from the cladistic and molecular revolutions that were taking place during the 1970s and 1980s, even as gastropods received considerable attention. Over the past ten years, cladistics and molecular systematics have begun to be applied to solve problems of bivalve evolutionary biology. These studies, most of which have been undertaken by paleontologists, have halted the stagnation in bivalve systematics. Bivalve systematics looks to have an exciting future, as the excellent fossil record of the Bivalvia will be used in conjunction with cladistics and molecular systematics to solve problems in not just bivalve evolution but evolutionary biology in general.

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The tale of the headless turtle

Zootaxa ◽

10.11646/zootaxa.4200.2.7 ◽

2016 ◽

Vol 4200 (2) ◽

pp. 327 ◽

Cited By ~ 2

Author(s):

PEDRO S. R. ROMANO

Keyword(s):

New Species ◽

Phenotypic Plasticity ◽

Lower Cretaceous ◽

Fossil Record ◽

Diagnostic Features ◽

Fossil Species ◽

The Past ◽

Early Paleocene ◽

Phylogenetic Hypotheses ◽

A New Species

Pelomedusoides is the most diverse clade of side-necked turtles and there is an extensive fossil record (de Broin, 1988; Lapparent de Broin, 2000; Gaffney et al., 2006, 2011) that dates back at least to the Barremian (Lower Cretaceous) (Romano et al., 2014). Its large fossil record evidences a greater diversity in the past, particularly at the end of the Mesozoic, and exhibits a good sampling of species that are represented by skull material (Gaffney et al., 2006, 2011). As a consequence, the most complete and recent phylogenetic hypotheses for this clade (e.g. Romano et al., 2014; Cadena, 2015) are based on matrices comprising a great amount of cranial characters derived largely from Gaffney et al. (2006, 2011). In addition, it is well established that shell characters show a lot of phenotypic plasticity, even in the fossil species (Romano, 2008; Gaffney et al., 2006, 2011). In most cases it consequently is not justified to rely on “diagnostic features” of poorly informative shell-only material for describing a new species. Because of that, most authors remark new morphotypes in the literature when such aberrant specimens are recovered, but do not make any nomenclatural act by proposing a new yet poorly supported species (e.g. Romano et al., 2013; Ferreira & Langer, 2013; Menegazzo et al., 2015). Unfortunately, such a supposedly new bothremydid turtle (Pleurodira: Bothremydidae) from the Early Paleocene of Brazil was recently described based on poorly diagnostic remains (Carvalho et al., 2016; hereafter CGB, for the authors initials) and a correction of this unfounded nomenclatural act is required. In addition I present some comments on shell only material from Brazil in order to guide splitter-taxonomists to stop describing poorly preserved fossil specimens as new species.

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3. Extinction in the past

Extinction: A Very Short Introduction ◽

10.1093/actrade/9780198807285.003.0003 ◽

2019 ◽

pp. 33-50

Author(s):

Paul B. Wignall

Keyword(s):

Fossil Record ◽

The Past ◽

Extinction Rates ◽

History Of ◽

Extinction Events

Despite the less-than-perfect nature of the fossil record, it still provides a unique window on the history of life, and reveals that there have been dramatic fluctuations in extinction intensities since complex life evolved around 600 million years ago. ‘Extinction in the past’ considers Jack Sepkoski’s database compiled in the 1980s, and his series of highly informative charts showing both diversity and extinction rates since the start of the Cambrian Period 541 million years ago. The calculation of extinction rates and the improved dating of extinction events are discussed, along with the extinction trends that can be observed. Fossils also provide valuable evidence on the nature of selection during extinction.

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How predictable is extinction? Forecasting species survival at million-year timescales

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2019.0392 ◽

2019 ◽

Vol 374 (1788) ◽

pp. 20190392 ◽

Cited By ~ 2

Author(s):

Peter Smits ◽

Seth Finnegan

Keyword(s):

Fossil Record ◽

Human Impacts ◽

Rank Order ◽

Extinction Risk ◽

Geographical Range ◽

The Past ◽

The Future ◽

Out Of Sample ◽

Extinction Events ◽

Over Time

A tenet of conservation palaeobiology is that knowledge of past extinction patterns can help us to better predict future extinctions. Although the future is unobservable, we can test the strength of this proposition by asking how well models conditioned on past observations would have predicted subsequent extinction events at different points in the geological past. To answer this question, we analyse the well-sampled fossil record of Cenozoic planktonic microfossil taxa (Foramanifera, Radiolaria, diatoms and calcareous nanoplankton). We examine how extinction probability varies over time as a function of species age, time of observation, current geographical range, change in geographical range, climate state and change in climate state. Our models have a 70–80% probability of correctly forecasting the rank order of extinction risk for a random out-of-sample species pair, implying that determinants of extinction risk have varied only modestly through time. We find that models which include either historical covariates or account for variation in covariate effects over time yield equivalent forecasts, but a model including both is overfit and yields biased forecasts. An important caveat is that human impacts may substantially disrupt range-risk dynamics so that the future will be less predictable than it has been in the past. This article is part of a discussion meeting issue ‘The past is a foreign country: how much can the fossil record actually inform conservation?’

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How the past impacts the future: modelling the performance of evolutionarily distinct mammals through time

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2019.0210 ◽

2019 ◽

Vol 374 (1788) ◽

pp. 20190210 ◽

Cited By ~ 1

Author(s):

D. J. Bennett ◽

M. D. Sutton ◽

S. T. Turvey

Keyword(s):

Fossil Record ◽

Distinct Species ◽

Performance Impact ◽

Deep Time ◽

The Past ◽

Living Fossils ◽

Measuring Change ◽

Molecular Phylogenetic ◽

Time Changes ◽

The One

How does past evolutionary performance impact future evolutionary performance? This is an important question not just for macroevolutionary biologists who wish to chart the phenomena that describe deep-time changes in biodiversity but also for conservation biologists, as evolutionarily distinct species—which may be deemed ‘low-performing’ in our current era—are increasingly the focus of conservation efforts. Contrasting hypotheses exist to account for the history and future of evolutionarily distinct species: on the one hand, they may be relicts of large radiations, potentially ‘doomed’ to extinction; or they may be slow-evolving, ‘living fossils’, likely neither to speciate nor go extinct; or they may be seeds of future radiations. Here, we attempt to test these hypotheses in Mammalia by combining a molecular phylogenetic supertree with fossil record occurrences and measuring change in evolutionary distinctness (ED) at different time slices. With these time slices, we modelled future ED as a function of past ED. We find that past evolutionary performance does indeed have an impact on future evolutionary performance: the most evolutionarily isolated clades tend to become more evolutionarily distinct with time, indicating that low-performing clades tend to remain low-performing throughout their evolutionary history. This article is part of a discussion meeting issue ‘The past is a foreign country: how much can the fossil record actually inform conservation?’

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The first potential fossil record of a dibamid reptile (Squamata: Dibamidae): a new taxon from the early Oligocene of Central Mongolia

Zoological Journal of the Linnean Society ◽

10.1093/zoolinnean/zlz047 ◽

2019 ◽

Vol 187 (3) ◽

pp. 782-799 ◽

Cited By ~ 3

Author(s):

Andrej Čerňanský

Keyword(s):

Fossil Record ◽

Evolutionary History ◽

Phylogenetic Analyses ◽

New Taxon ◽

Unique Combination ◽

Central Mongolia ◽

Squamate Reptiles ◽

The Past ◽

Early Oligocene ◽

Fossil Material

Abstract Dibamid reptiles have a known current distribution on two continents (Asia and North America). Although this clade represents an early-diverging group in the Squamata and thus should have a long evolutionary history, no fossil record of these peculiar burrowing squamate reptiles has been documented so far. The fossil material described here comes from the early Oligocene of the Valley of Lakes in Central Mongolia. This material consists of jaws and is placed in the clade Dibamidae on the basis of its morphology, which is further confirmed by phylogenetic analyses. In spite of the fragmentary nature of this material, it thus forms the first, but putative, fossil evidence of this clade. If correctly interpreted, this material demonstrates the occurrence of Dibamidae in East Asia in the Palaeogene, indicating its distribution in higher latitudes than today. The preserved elements possess a unique combination of character states, and a new taxon name is therefore erected: Hoeckosaurus mongoliensis sp. nov. The dentary of Hoeckosaurus exhibits some characters of the two extant dibamid taxa. However, the open Meckel’s groove, together with other characters, show that this group was morphologically much more diverse in the past.

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Fossil-calibrated molecular phylogeny of atlantid heteropods (Gastropoda, Pterotracheoidea)

BMC Evolutionary Biology ◽

10.1186/s12862-020-01682-9 ◽

2020 ◽

Vol 20 (1) ◽

Cited By ~ 1

Author(s):

Deborah Wall-Palmer ◽

Arie W. Janssen ◽

Erica Goetze ◽

Le Qin Choo ◽

Lisette Mekkes ◽

...

Keyword(s):

Fossil Record ◽

Large Scale ◽

Global Scale ◽

The Other ◽

The Past ◽

The Family ◽

Rapid Diversification ◽

Maximum Likelihood Phylogeny ◽

Extinction Events ◽

Ribosomal Rrna

Abstract Background The aragonite shelled, planktonic gastropod family Atlantidae (shelled heteropods) is likely to be one of the first groups to be impacted by imminent ocean changes, including ocean warming and ocean acidification. With a fossil record spanning at least 100 Ma, atlantids have experienced and survived global-scale ocean changes and extinction events in the past. However, the diversification patterns and tempo of evolution in this family are largely unknown. Results Based on a concatenated maximum likelihood phylogeny of three genes (cytochrome c oxidase subunit 1 mitochondrial DNA, 28S and 18S ribosomal rRNA) we show that the three extant genera of the family Atlantidae, Atlanta, Protatlanta and Oxygyrus, form monophyletic groups. The genus Atlanta is split into two groups, one exhibiting smaller, well ornamented shells, and the other having larger, less ornamented shells. The fossil record, in combination with a fossil-calibrated phylogeny, suggests that large scale atlantid extinction was accompanied by considerable and rapid diversification over the last 25 Ma, potentially driven by vicariance events. Conclusions Now confronted with a rapidly changing modern ocean, the ability of atlantids to survive past global change crises gives some optimism that they may be able to persist through the Anthropocene.

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