scholarly journals Enduring evolutionary embellishment of cloudinids in the Cambrian

2021 ◽  
Vol 8 (12) ◽  
Author(s):  
Tae-Yoon S. Park ◽  
Jikhan Jung ◽  
Mirinae Lee ◽  
Sangmin Lee ◽  
Yong Yi Zhen ◽  
...  
Keyword(s):  
Asexual Reproduction ◽  
Fossil Record ◽  
Evolutionary History ◽  
Structural Complexity ◽  
Cambrian Explosion ◽  
Animal Group ◽  
Reproduction Mode ◽  
First Case ◽  
History Of ◽  
Mode Tracking

The Ediacaran–Cambrian transition and the following Cambrian Explosion are among the most fundamental events in the evolutionary history of animals. Understanding these events is enhanced when phylogenetic linkages can be established among animal fossils across this interval and their trait evolution monitored. Doing this is challenging because the fossil record of animal lineages that span this transition is sparse, preserved morphologies generally simple and lifestyles in the Ediacaran and Cambrian commonly quite different. Here, we identify derived characters linking some members of an enigmatic animal group, the cloudinids, which first appeared in the Late Ediacaran, to animals with cnidarian affinity from the Cambrian Series 2 and the Miaolingian. Accordingly, we present the first case of an animal lineage represented in the Ediacaran that endured and diversified successfully throughout the Cambrian Explosion by embellishing its overall robustness and structural complexity. Among other features, dichotomous branching, present in some early cloudinids, compares closely with a cnidarian asexual reproduction mode. Tracking this morphological change from Late Ediacaran to the Miaolingian provides a unique glimpse into how a primeval animal group responded during the Cambrian Explosion.

Ontogeny in the fossil record: diversification of body plans and the evolution of “aberrant” symmetry in Paleozoic echinoderms

Paleobiology ◽  
2007 ◽  
Vol 33 (1) ◽  
pp. 149-163 ◽  
Author(s):  
Colin D. Sumrall ◽  
Gregory A. Wray
Keyword(s):  
Great Reduction ◽  
Fossil Record ◽  
Evolutionary History ◽  
Total Loss ◽  
Cambrian Explosion ◽  
Growth Stages ◽  
Ecological Constraints ◽  
Fivefold Symmetry ◽  
Primary Body ◽  
History Of

Echinoderms have long been characterized by the presence of ambulacra that exhibit pentaradiate symmetry and define five primary body axes. In reality, truly pentaradial ambulacral symmetry is a condition derived only once in the evolutionary history of echinoderms and is restricted to eleutherozoans, the clade that contains most living echinoderm species. In contrast, early echinoderms have a bilaterally symmetrical 2-1-2 arrangement, with three ambulacra radiating from the mouth. Branching of the two side ambulacra during ontogeny produces the five adult rays. During the Cambrian Explosion and Ordovician Radiation, some 30 clades of echinoderms evolved, many of which have aberrant ambulacral systems with one to four rays. Unfortunately, no underlying model has emerged that explains ambulacral homologies among disparate forms. Here we show that most Paleozoic echinoderms are characterized by uniquely identifiable ambulacra that develop in three distinct postlarval stages. Nearly all “aberrant” echinoderm morphologies can be explained by the paedomorphic ambulacra reduction (PAR) model through the loss of some combination of these growth stages during ontogeny. Superficially similar patterns of ambulacral reduction in distantly related clades have resulted from the parallel loss of homologous ambulacra during ontogeny. Pseudo-fivefold symmetry seen in Blastoidea and the true fivefold symmetry seen in Eleutherozoa result from great reduction and total loss, respectively, of the 2–1–2 symmetry early in ontogeny. These ambulacral variations suggest that both developmental and ecological constraints affect the evolution of novel echinoderm body plans.

A fossil record of land plant origins from charophyte algae

Science ◽  
2021 ◽  
Vol 373 (6556) ◽  
pp. 792-796 ◽  
Author(s):  
Paul K. Strother ◽  
Clinton Foster
Keyword(s):  
Fossil Record ◽  
Evolutionary History ◽  
Phylogenetic Signal ◽  
Land Plant ◽  
Fossil Plants ◽  
Fossil Plant ◽  
Molecular Phylogenetic ◽  
History Of ◽  
Time Gap ◽  
Evolutionary Continuity

Molecular time trees indicating that embryophytes originated around 500 million years ago (Ma) during the Cambrian are at odds with the record of fossil plants, which first appear in the mid-Silurian almost 80 million years later. This time gap has been attributed to a missing fossil plant record, but that attribution belies the case for fossil spores. Here, we describe a Tremadocian (Early Ordovician, about 480 Ma) assemblage with elements of both Cambrian and younger embryophyte spores that provides a new level of evolutionary continuity between embryophytes and their algal ancestors. This finding suggests that the molecular phylogenetic signal retains a latent evolutionary history of the acquisition of the embryophytic developmental genome, a history that perhaps began during Ediacaran-Cambrian time but was not completed until the mid-Silurian (about 430 Ma).

scholarly journals Experimental degradation of helicoidal photonic nanostructures in scarab beetles (Coleoptera: Scarabaeidae): implications for the identification of circularly polarizing cuticle in the fossil record

2018 ◽  
Vol 15 (148) ◽  
pp. 20180560 ◽  
Author(s):  
Giliane P. Odin ◽  
Maria E. McNamara ◽  
Hans Arwin ◽  
Kenneth Järrendahl
Keyword(s):  
Uric Acid ◽  
Fossil Record ◽  
Evolutionary History ◽  
Polarized Light ◽  
Circularly Polarized Light ◽  
Circularly Polarized ◽  
Alkaline Conditions ◽  
History Of ◽  
Diagenetic History ◽  
Scarab Beetles

Scarab beetles (Coleoptera: Scarabaeidae) can exhibit striking colours produced by pigments and/or nanostructures. The latter include helicoidal (Bouligand) structures that can generate circularly polarized light. These have a cryptic evolutionary history in part because fossil examples are unknown. This suggests either a real biological signal, i.e. that Bouligand structures did not evolve until recently, or a taphonomic signal, i.e. that conditions during the fossilization process were not conducive to their preservation. We address this issue by experimentally degrading circularly polarizing cuticle of modern scarab beetles to test the relative roles of decay, maturation and taxonomy in controlling preservation. The results reveal that Bouligand structures have the potential to survive fossilization, but preservation is controlled by taxonomy and the diagenetic history of specimens. Further, cuticle of specific genus ( Chrysina ) is particularly decay-prone in alkaline conditions; this may relate to the presence of certain compounds, e.g. uric acid, in the cuticle of these taxa.

scholarly journals A comparative atlas of the skull osteology of European lizards (Reptilia: Squamata)

2019 ◽  
Vol 187 (3) ◽  
pp. 829-928 ◽  
Author(s):  
Andrea Villa ◽  
Massimo Delfino
Keyword(s):  
Fossil Record ◽  
Evolutionary History ◽  
European Species ◽  
History Of ◽  
Diagnostic Key ◽  
Single Bone ◽  
Fossil Lizards ◽  
Bone Remains ◽  
Comparative Osteology ◽  
Broad Scale

Abstract The fossil record provides evidence of a long evolutionary history of European lizards. Since fossil lizards are regularly represented by bone remains, the knowledge of the origins of extant taxa and their distribution in time and space is hindered by the fact that their comparative osteology is not yet completely and adequately known. In spite of a rising interest in this topic since the end of the 20th century, a gap in our knowledge is still evident. We here report the first broad-scale comparative osteological analysis of the skulls of extant European lizards, highlighting significant differences that can be used in identification. This comparative study, including as many European species as possible, leads to the creation of a detailed diagnostic key for each single bone. Also, our data significantly improve the recognizability of extant European non-snake squamates, with 54% of the current diversity to be recognized based on the new results contra the previously estimated 31%. This recognizability is expected to further increase in the future, with new studies focusing on species that are either missing or poorly represented here, or applying promising advanced methodologies.

scholarly journals Diversification events and the effects of mass extinctions on Crocodyliformes evolutionary history

2015 ◽  
Vol 2 (5) ◽  
pp. 140385 ◽  
Author(s):  
Mario Bronzati ◽  
Felipe C. Montefeltro ◽  
Max C. Langer
Keyword(s):  
Mass Extinction ◽  
Fossil Record ◽  
Evolutionary History ◽  
Continuous Process ◽  
Mass Extinctions ◽  
Terrestrial Habitats ◽  
History Of ◽  
The Rich ◽  
A Minor ◽  
Diversification Event

The rich fossil record of Crocodyliformes shows a much greater diversity in the past than today in terms of morphological disparity and occupation of niches. We conducted topology-based analyses seeking diversification shifts along the evolutionary history of the group. Our results support previous studies, indicating an initial radiation of the group following the Triassic/Jurassic mass extinction, here assumed to be related to the diversification of terrestrial protosuchians, marine thalattosuchians and semi-aquatic lineages within Neosuchia. During the Cretaceous, notosuchians embodied a second diversification event in terrestrial habitats and eusuchian lineages started diversifying before the end of the Mesozoic. Our results also support previous arguments for a minor impact of the Cretaceous/Palaeogene mass extinction on the evolutionary history of the group. This argument is not only based on the information from the fossil record, which shows basal groups surviving the mass extinction and the decline of other Mesozoic lineages before the event, but also by the diversification event encompassing only the alligatoroids in the earliest period after the extinction. Our results also indicate that, instead of a continuous process through time, Crocodyliformes diversification was patchy, with events restricted to specific subgroups in particular environments and time intervals.

scholarly journals “Small Size” in the Philippine Human Fossil Record: Is it Meaningful for a Better Understanding of the Evolutionary History of the Negritos?

Human Biology ◽  
2013 ◽  
Vol 85 (1-3) ◽  
pp. 45-66 ◽  
Author(s):  
Florent Détroit ◽  
Julien Corny ◽  
Eusebio Z. Dizon ◽  
Armand S. Mijares
Keyword(s):  
Fossil Record ◽  
Evolutionary History ◽  
Human Fossil ◽  
History Of

Where Fossils Dare and Males Matter: combined morphological and molecular analysis untangles the evolutionary history of the spider ant genus Leptomyrmex Mayr (Hymenoptera : Dolichoderinae)

2017 ◽  
Vol 31 (6) ◽  
pp. 765 ◽  
Author(s):  
Phillip Barden ◽  
Brendon Boudinot ◽  
Andrea Lucky
Keyword(s):  
Evolutionary History ◽  
Morphological Evolution ◽  
Sister Group ◽  
Morphological Characters ◽  
Fossil Material ◽  
First Case ◽  
History Of ◽  
The Impact ◽  
Surprising Discovery

The distinctive ant genus Leptomyrmex Mayr, 1862 had been thought to be endemic to Australasia for over 150 years, but enigmatic Neotropical fossils have challenged this view for decades. The present study responds to a recent and surprising discovery of extant Leptomyrmex species in Brazil with a thorough evaluation of the Dominican Republic fossil material, which dates to the Miocene. In the first case study of direct fossil inclusion within Formicidae Latreille, 1809, we incorporated both living and the extinct Leptomyrmex species. Through simultaneous analysis of molecular and morphological characters in both Bayesian and parsimony frameworks, we recovered the fossil taxon as sister-group to extant Leptomyrmex in Brazil while considering the influence of taxonomic and character sampling on inferred hypotheses relating to tree topology, biogeography and morphological evolution. We also identified potential loss of signal in the binning of morphological characters and tested the impact of parameterisation on divergence date estimation. Our results highlight the importance of securing sufficient taxon sampling for extant lineages when incorporating fossils and underscore the utility of diverse character sources in accurate placement of fossil terminals. Specifically, we find that fossil placement in this group is influenced by the inclusion of male-based characters and the newly discovered Neotropical ‘Lazarus taxon’.

The first diplatyid earwig in Tertiary amber (Dermaptera: Diplatyidae): A new species from Miocene Mexican amber

2013 ◽  
Vol 44 (2) ◽  
pp. 157-166 ◽  
Author(s):  
Andrew J. Ross ◽  
Michael S. Engel
Keyword(s):  
New Species ◽  
Adult Female ◽  
Fossil Record ◽  
Evolutionary History ◽  
History Of ◽  
A New Species

The first earwig (Dermaptera) to be described from Mexican (Miocene) amber is named Haplodiplatys crightoni Ross & Engel sp.n., represented by an adult female and constituting the second record of the basal family Diplatyidae in the fossil record. Brief comments are made regarding the biogeographic implications of the fossil and the evolutionary history of Diplatyidae.

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