Phylogeny and classification of echinoids

Kroh, Andreas

doi:10.1016/b978-0-12-819570-3.00001-9

Cited by 22 publications

(41 citation statements)

References 69 publications

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“…The copyright holder for this preprint (which this version posted July 20, 2021. ; https://doi.org/10.1101/2021.07. 19.453013 doi: bioRxiv preprint 4 main lineages, Cidaroidea and Euechinoidea) occurred in the Late Permian, as supported by molecular estimates of divergence [13,14], as well as the occurrence of Permian fossils with morphologies typical of modern cidaroids [15,16]. However, a recent total-evidence study recovered many taxa previously classified as crown group members along the echinoid stem, while also suggesting that up to three crown group lineages survived the P-T mass extinction [3].…”

Section: Introductionmentioning

confidence: 99%

“…This result increases the discrepancy between molecular estimates and the fossil record and renders uncertain the early evolutionary history of crown group echinoids. Constraining the timing of origin of this clade relative to the P-T mass extinction (especially in the light of recent topological changes [3,4]) is further complicated by the poor preservation potential of stem group echinoids, and the difficulty assigning available disarticulated remains from the Late Palaeozoic and Early Triassic to specific clades [11,12,[17][18][19][20].…”

Section: Introductionmentioning

confidence: 99%

“…The clade includes greatly flattened forms that live in high-energy sandy environments where they feed using a unique mechanism for selecting and transporting organic particles to the mouth, where these are crushed using well-developed jaws [25,26]. Sand dollars (Scutelloida) were long thought to be most closely related to sea biscuits (Clypeasteroida) given a wealth of shared morphological characters [19,25]. The extraordinary fossil record of both sand dollars and sea biscuits suggested their last common ancestor originated in the early Cenozoic from among an assemblage known as "cassiduloids" [23,25], a once diverse group that is today represented by three depauperate lineages: cassidulids (and close relatives), echinolampadids, and apatopygids [19,27].…”

Section: Introductionmentioning

confidence: 99%

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Phylogenomic analyses of echinoid diversification prompt a re-evaluation of their fossil record

Koch

Thompson

Hatch

et al. 2021

Preprint

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Echinoids are key components of modern marine ecosystems. Despite a remarkable fossil record, the emergence of their crown group is documented by few specimens of unclear affinities, rendering their early history uncertain. The origin of sand dollars, one of its most distinctive clades, is also unclear due to an unstable phylogenetic context. We employ seventeen novel genomes and transcriptomes to build a dataset with a near-complete sampling of major lineages and use it to revise the phylogeny and divergence times of echinoids. We introduce the concept of a chronospace - a multidimensional representation of node ages - and use it to explore the effects of using alternative gene samples, models of molecular evolution, and clock priors. We find the choice of clock model to have the strongest impact on divergence times, while gene sampling and the use of site-heterogeneous models show little effects. Crown group echinoids originated in the Permian and diversified rapidly in the Triassic. We clarify the relationships among sand dollars and their close relatives, showing that Apatopygus represents a relict lineage with a deep Jurassic origin. Sand dollars are confidently dated to the Cretaceous, implying ghost ranges spanning approximately 50 million years, a remarkable discrepancy with their fossil record.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Phylogenomic analyses of echinoid diversification prompt a re-evaluation of their fossil record

Koch

Thompson

Hatch

et al. 2021

Preprint

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“…Body size is log 10 ‐scaled and shown relative to the value of the average optimum (4.08; see Table 2). Clade names follow the nomenclature of Kroh (2019) and Mongiardino Koch and Thompson (2020). The echinoids shown are members of each of the four adaptive regimes and are shown to scale.…”

Section: Resultsmentioning

confidence: 99%

Exploring adaptive landscapes across deep time: A case study using echinoid body size

Koch

2021

Evolution

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Adaptive landscapes are a common way of conceptualizing the phenotypic evolution of lineages across deep time. Although multiple approaches exist to implement this concept into operational models of trait evolution, inferring adaptive landscapes from comparative datasets remains challenging. Here, I explore the macroevolutionary dynamics of echinoid body size using data from over 5000 specimens and a phylogenetic framework incorporating a dense fossil sampling and spanning approximately 270 million years. Furthermore, I implement a novel approach of exploring alternative parameterizations of adaptive landscapes that succeeds in finding simpler, yet better‐fitting models. Echinoid body size has been constrained to evolve within a single adaptive optimum for much of the clade's history. However, most of the morphological disparity of echinoids was generated by multiple regime shifts that drove the repeated evolution of miniaturized and gigantic forms. Events of body size innovation occurred predominantly in the Late Cretaceous and were followed by a drastic slowdown following the Cretaceous‐Paleogene mass extinction. The discovery of these patterns is contingent upon directly sampling fossil taxa. The macroevolution of echinoid body size is therefore characterized by a late increase in disparity (likely linked to an expansion of ecospace), generated by active processes driving lineages toward extreme morphologies.

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“…Taxa subjected to phylogenetic analysis and relevant material examined are listed in Table 1. We follow the classification scheme of Smith and Kroh (2011) as it has been widely utilized, although an updated classification has recently been presented by Kroh (2020).…”

Section: Methodsmentioning

confidence: 99%

Phylogeny and biogeography of some Cretaceous spatangoid echinoids with special emphasis on taxa from the Western Interior Seaway

Byrum

Lieberman

2020

J. Paleontol.

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Members of the echinoid order Spatangoida, a highly diverse and abundant marine invertebrate clade, were important denizens of the Cretaceous Western Interior Seaway (WIS), an epicontinental seaway that divided North America in two during an interval of greenhouse conditions between roughly 100 and 65 million years ago. A phylogenetic analysis of spatangoids was conducted using a character matrix of 32 characters from 21 species. Species that occur in the WIS were considered comprehensively, and species from other regions such as South America, Europe, and North Africa were also incorporated into the analysis. Phylogenetic patterns retrieved are largely congruent with preexisting family-level classifications; however, species within several genera, especially Hemiaster and Heteraster, need to be reassigned so that classification better reflects phylogeny. The genera Washitaster and Heteraster are closely related, as are Mecaster, Palhemiaster, and Proraster; Pliotoxaster, Macraster, and Hemiaster; and Micraster and Diplodetus. Biogeographic patterns were also considered using the phylogeny, and several episodes of vicariance and range expansion were identified. These were possibly related to some of the various major episodes of sea-level rise and fall during the Cretaceous. In particular, Valangian–mid-Aptian regressions may have caused vicariance within Heteraster and Washitaster while other early spatangoid vicariance may be related to regressions during the late Aptian–early Cenomanian. Further, vicariance caused by regressions during the mid-Cenomanian–Maastrichtian may have driven diversification within Micraster and Diplodetus. Last, transgressions during the late Aptian–early Cenomanian seem to have spurred prominent range expansions in Mecaster and Hemiaster.

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Phylogeny and classification of echinoids

Cited by 22 publications

References 69 publications

Phylogenomic analyses of echinoid diversification prompt a re-evaluation of their fossil record

Phylogenomic analyses of echinoid diversification prompt a re-evaluation of their fossil record

Exploring adaptive landscapes across deep time: A case study using echinoid body size

Phylogeny and biogeography of some Cretaceous spatangoid echinoids with special emphasis on taxa from the Western Interior Seaway

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