Integrating phylogeny, molecular clocks, and the fossil record in the evolution of coralline algae (Corallinales and Sporolithales, Rhodophyta)

Paleobiology ◽  
2010 ◽  
Vol 36 (4) ◽  
pp. 519-533 ◽  
Author(s):  
Julio Aguirre ◽  
Francisco Perfectti ◽  
Juan C. Braga

When assessing the timing of branching events in a phylogeny, the most important tools currently recognized are a reliable molecular phylogeny and a continuous, relatively complete fossil record. Coralline algae (Rhodophyta, Corallinales, and Sporolithales) constitute an ideal group for this endeavor because of their excellent fossil record and their consistent phylogenetic reconstructions. We present the evolutionary history of the corallines following a novel, combined approach using their fossil record, molecular phylogeny (based on the 18S rDNA gene sequences of 39 coralline species), and molecular clocks. The order of appearance of the major monophyletic taxa of corallines in the fossil record perfectly matches the sequence of branching events in the phylogeny. We were able to demonstrate the robustness of the node ages in the phylogeny based on molecular clocks by performing an analysis of confidence intervals and maximum temporal ranges of three monophyletic groups of corallines (the families Sporolithaceae and Hapalidiaceae, as well as the subfamily Lithophylloideae). The results demonstrate that their first occurrences are close to their observed appearances, a clear indicator of a very complete stratigraphic record. These chronological data are used to confidently constrain the ages of the remaining branching events in the phylogeny using molecular clocks.

Science ◽  
2021 ◽  
Vol 373 (6556) ◽  
pp. 792-796 ◽  
Author(s):  
Paul K. Strother ◽  
Clinton Foster

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).


2018 ◽  
Vol 15 (148) ◽  
pp. 20180560 ◽  
Author(s):  
Giliane P. Odin ◽  
Maria E. McNamara ◽  
Hans Arwin ◽  
Kenneth Järrendahl

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.


2008 ◽  
Vol 8 (1) ◽  
pp. 205 ◽  
Author(s):  
Martin Kolisko ◽  
Ivan Cepicka ◽  
Vladimir Hampl ◽  
Jessica Leigh ◽  
Andrew J Roger ◽  
...  

Hemoglobin ◽  
2018 ◽  
pp. 94-123
Author(s):  
Jay F. Storz

Chapter 5 provides an overview of the evolutionary history of the globin gene superfamily and places the evolution of vertebrate-specific globins in phylogenetic context. The duplication and functional divergence of globin genes has promoted key physiological innovations in respiratory gas transport and other physiological functions during animal evolution. A combination of both tandem gene duplication and whole-genome duplication contributed to the diversification of vertebrate globins. Phylogenetic reconstructions arrange vertebrate globins into those that derive from vertebrate-specific duplications (cytoglobin, globin E, globin Y, and the independently derived myoglobin-like and hemoglobin-like genes of jawed vertebrates and jawless fishes [lampreys and hagfish]) and those that derive from far more ancient duplication events that predate the divergence between deuterostomes and protostomes (androglobin, globin X, and neuroglobin). Tracing the evolutionary history of deuterostome globins reveals evidence for the repeated culling of ancestral diversity, followed by lineage-specific diversification of surviving gene lineages via repeated rounds of duplication and divergence.


2019 ◽  
Vol 187 (3) ◽  
pp. 829-928 ◽  
Author(s):  
Andrea Villa ◽  
Massimo Delfino

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.


Paleobiology ◽  
2007 ◽  
Vol 33 (1) ◽  
pp. 149-163 ◽  
Author(s):  
Colin D. Sumrall ◽  
Gregory A. Wray

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.


2005 ◽  
Vol 35 (1) ◽  
pp. 281-286 ◽  
Author(s):  
Masayoshi Tokita ◽  
Taku Okamoto ◽  
Tsutomu Hikida

Paleobiology ◽  
2015 ◽  
Vol 41 (1) ◽  
pp. 45-67 ◽  
Author(s):  
Benjamin Kotrc ◽  
Andrew H. Knoll

AbstractBoth molecular clocks and the first appearances of major groups in the fossil record suggest that most of the range of diatom morphologies observed today had evolved by the end of the Cretaceous Period. Despite this, a canonical reading of the Cenozoic fossil record suggests a dramatic rise in taxonomic diversity that can be interpreted as an explosion of morphological variety. We investigated this apparent discrepancy by using a discrete-character-based, empirical diatom morphospace, resolved by molecular phylogeny and by fossil occurrences through time. The morphospace shows little correspondence to phylogeny and little Cenozoic change in disparity as measured by mean pairwise distance. There is, however, an increase in the total volume of morphospace occupied. Although the increase in occupied volume through time ostensibly supports a conclusion of increasing morphological variety, sampling biases and other data suggest an underlying stationary pattern more consistent with molecular clock data.


2015 ◽  
Vol 2 (5) ◽  
pp. 140385 ◽  
Author(s):  
Mario Bronzati ◽  
Felipe C. Montefeltro ◽  
Max C. Langer

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.


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