Reinterpretation of the Cambrian ‘bryozoan’ Pywackia as an octocoral

Pywackia baileyi Landing in Landing et al., 2010, from the upper Cambrian Yudachica Member of Oaxaca State, southern Mexico, consists of small, phosphatic, proximally tapering cylindrical rods covered by shallow polygonal calices. The bryozoan-like morphology of this fossil prompted its interpretation as the first bryozoan known from the Cambrian. However, restudy of some of the original material, employing scanning electron microscopy for the first time, questions the assignment of Pywackia to the Bryozoa. Striking similarities between Pywackia and the modern pennatulacean octocoral Lituaria lead to an alternative hypothesis interpreting Pywackia an early fossil octocoral. While Pywackia is probably not a true pennatulacean, a group with a definitive fossil record stretching back only to the Late Cretaceous, it can be envisaged as having had a similar skeletal structure and ecology to Lituaria, the rods representing mineralized axes of tiny colonies that lived with their proximal ends buried in the sediment and distal ends covered by feeding polyps. Landing et al. (2010) considered the phosphatic composition of Pywackia specimens to be the result of diagenetic replacement, but the evidence is equivocal. If Pywackia had a primary phosphatic skeleton, this would support the hypothesized existence of phosphatic biomineralization early in the evolutionary history of Cnidaria, as well as providing further evidence that Pywackia is not a bryozoan.

Download Full-text

Ecological correlates of ghost lineages in ruminants

Paleobiology ◽

10.1017/s0094837300000427 ◽

2012 ◽

Vol 38 (1) ◽

pp. 101-111 ◽

Cited By ~ 2

Author(s):

Juan L. Cantalapiedra ◽

Manuel Hernández Fernández ◽

Gema M. Alcalde ◽

Beatriz Azanza ◽

Daniel DeMiguel ◽

...

Keyword(s):

Fossil Record ◽

Generalized Estimating Equations ◽

Evolutionary History ◽

Phylogenetic Systematics ◽

Temporal Factors ◽

Preservation Potential ◽

History Of ◽

First Time ◽

Pearson Correlations ◽

Bone Remains

Integration between phylogenetic systematics and paleontological data has proved to be an effective method for identifying periods that lack fossil evidence in the evolutionary history of clades. In this study we aim to analyze whether there is any correlation between various ecomorphological variables and the duration of these underrepresented portions of lineages, which we call ghost lineages for simplicity, in ruminants. Analyses within phylogenetic (Generalized Estimating Equations) and non-phylogenetic (ANOVAs and Pearson correlations) frameworks were performed on the whole phylogeny of this suborder of Cetartiodactyla (Mammalia). This is the first time ghost lineages are focused in this way. To test the robustness of our data, we compared the magnitude of ghost lineages among different continents and among phylogenies pruned at different ages (4, 8, 12, 16, and 20 Ma). Differences in mean ghost lineage were not significantly related to either geographic or temporal factors. Our results indicate that the proportion of the known fossil record in ruminants appears to be influenced by the preservation potential of the bone remains in different environments. Furthermore, large geographical ranges of species increase the likelihood of preservation.

Download Full-text

A fossil record of land plant origins from charophyte algae

Science ◽

10.1126/science.abj2927 ◽

2021 ◽

Vol 373 (6556) ◽

pp. 792-796 ◽

Cited By ~ 1

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).

Download Full-text

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

Journal of The Royal Society Interface ◽

10.1098/rsif.2018.0560 ◽

2018 ◽

Vol 15 (148) ◽

pp. 20180560 ◽

Cited By ~ 3

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.

Download Full-text

Fossil flower of Staphylea L. from the Miocene amber of Mexico: New evidence of the Boreotropical Flora in low-latitude North America

Earth and Environmental Science Transactions of the Royal Society of Edinburgh ◽

10.1017/s1755691018000701 ◽

2017 ◽

Vol 108 (4) ◽

pp. 471-478 ◽

Cited By ~ 1

Author(s):

Ana L. Hernández-Damián ◽

Sergio R. S. Cevallos-Ferriz ◽

Alma R. Huerta-Vergara

Keyword(s):

North America ◽

Northern Hemisphere ◽

Fossil Record ◽

First Record ◽

High Latitudes ◽

Low Latitude ◽

Southern Mexico ◽

Apparent Lack ◽

History Of ◽

New Evidence

ABSTRACTA new flower preserved in amber in sediments of Simojovel de Allende, México, is identified as an extinct member of Staphyleaceae, a family of angiosperms consisting of only three genera (Staphylea, Turpinia and Euscaphis), which has a large and abundant fossil record and is today distributed over the Northern Hemisphere. Staphylea ochoterenae sp. nov. is the first record of a flower for this group, which is small, pedicelled, pentamer, bisexual, with sepals and petals with similar size, dorsifixed anthers and superior ovary. Furthermore, the presence of stamens with pubescent filaments allows close comparison with extant flowers of Staphylea bulmada and S. forresti, species currently growing in Asia. However, their different number of style (one vs. three) and the apparent lack of a floral disc distinguish them from S. ochoterenae. The presence of Staphyleaceae in southern Mexico ca. 23 to 15My ago is evidence of the long history of integration of vegetation in low-latitude North America, in which some lineages, such as Staphylea, could move southwards from high latitudes of the Northern Hemisphere, as part of the Boreotropical Flora. In Mexico it grew in association with tropical elements, as suggested by the fossil record of the area.

Download Full-text

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

Zoological Journal of the Linnean Society ◽

10.1093/zoolinnean/zlz035 ◽

2019 ◽

Vol 187 (3) ◽

pp. 829-928 ◽

Cited By ~ 5

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.

Download Full-text

Re-Defining Canis etruscus (Canidae, Mammalia): A New Look into the Evolutionary History of Early Pleistocene Dogs Resulting from the Outstanding Fossil Record from Pantalla (Italy)

Journal of Mammalian Evolution ◽

10.1007/s10914-013-9227-4 ◽

2013 ◽

Vol 21 (1) ◽

pp. 95-110 ◽

Cited By ~ 15

Author(s):

Marco Cherin ◽

Davide F. Bertè ◽

Lorenzo Rook ◽

Raffaele Sardella

Keyword(s):

Fossil Record ◽

Evolutionary History ◽

Early Pleistocene ◽

History Of ◽

New Look

Download Full-text

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

Paleobiology ◽

10.1666/06053.1 ◽

2007 ◽

Vol 33 (1) ◽

pp. 149-163 ◽

Cited By ~ 66

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.

Download Full-text

Brilliant angle-independent structural colours preserved in weevil scales from the Swiss Pleistocene

Biology Letters ◽

10.1098/rsbl.2020.0063 ◽

2020 ◽

Vol 16 (4) ◽

pp. 20200063

Author(s):

Luke T. McDonald ◽

Suresh Narayanan ◽

Alec Sandy ◽

Vinodkumar Saranathan ◽

Maria E. McNamara

Keyword(s):

Fossil Record ◽

Evolutionary History ◽

Three Dimensional ◽

Far Field ◽

Poor Knowledge ◽

X Ray ◽

Evolutionary Origins ◽

X Ray Scattering ◽

Colour Palette ◽

Scanning Electron

Extant weevils exhibit a remarkable colour palette that ranges from muted monochromatic tones to rainbow-like iridescence, with the most vibrant colours produced by three-dimensional photonic nanostructures housed within cuticular scales. Although the optical properties of these nanostructures are well understood, their evolutionary history is not fully resolved, in part due to a poor knowledge of their fossil record. Here, we report three-dimensional photonic nanostructures preserved in brightly coloured scales of two weevils, belonging to the genus Phyllobius or Polydrusus , from the Pleistocene (16–10 ka) of Switzerland. The scales display vibrant blue, green and yellow hues that resemble those of extant Phyllobius/Polydrusus . Scanning electron microscopy and small-angle X-ray scattering analyses reveal that the subfossil scales possess a single-diamond photonic crystal nanostructure. In extant Phyllobius/Polydrusus , the near-angle-independent blue and green hues function primarily in crypsis. The preservation of far-field, angle-independent structural colours in the Swiss subfossil weevils and their likely function in substrate matching confirm the importance of investigating fossil and subfossil photonic nanostructures to understand the evolutionary origins and diversification of colours and associated behaviours (e.g. crypsis) in insects.

Download Full-text

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

Royal Society Open Science ◽

10.1098/rsos.140385 ◽

2015 ◽

Vol 2 (5) ◽

pp. 140385 ◽

Cited By ~ 43

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.

Download Full-text