Revisiting a Landmark Study System: No Evidence for a Punctuated Mode of Evolution in<i>Metrarabdotos</i>

Voje, Kjetil L.; Martino, Emanuela Di; Porto, Arthur

doi:10.1086/707664

Cited by 12 publications

(11 citation statements)

References 85 publications

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“…We captured nuances in the dynamics of trait evolution given changing environmental and ecological conditions over geological timescales and corroborated the lack of phenotypic stasis in the fossil record found in recent work [59]. While previous studies investigate life-history traits [60] and pioneered quantitative genetics using fossil organisms [61,62], this is the first attempt at quantifying trait-fitness associations and understanding how they align with long-term phenotypic evolution, given the backdrop of climate change and ecological interactions.…”

Section: Discussionsupporting

confidence: 79%

Trait–fitness associations do not predict within-species phenotypic evolution over 2 million years

Martino

Liow

2021

Proc. R. Soc. B.

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Long-term patterns of phenotypic change are the cumulative results of tens of thousands to millions of years of evolution. Yet, empirical and theoretical studies of phenotypic selection are largely based on contemporary populations. The challenges in studying phenotypic evolution, in particular trait–fitness associations in the deep past, are barriers to linking micro- and macroevolution. Here, we capitalize on the unique opportunity offered by a marine colonial organism commonly preserved in the fossil record to investigate trait–fitness associations over 2 Myr. We use the density of female polymorphs in colonies of Antartothoa tongima as a proxy for fecundity, a fitness component, and investigate multivariate signals of trait–fitness associations in six time intervals on the backdrop of Pleistocene climatic shifts. We detect negative trait–fitness associations for feeding polymorph (autozooid) sizes, positive associations for autozooid shape but no particular relationship between fecundity and brood chamber size. In addition, we demonstrate that long-term trait patterns are explained by palaeoclimate (as approximated by ∂ 18 O), and to a lesser extent by ecological interactions (i.e. overgrowth competition and substrate crowding). Our analyses show that macroevolutionary outcomes of trait evolution are not a simple scaling-up from the trait–fitness associations.

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Section: Discussionsupporting

confidence: 79%

Trait–fitness associations do not predict within-species phenotypic evolution over 2 million years

Martino

Liow

2021

Proc. R. Soc. B.

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“…Genetic diversity levels higher than reported are frequently estimated in taxonomic revisions that include molecular studies, often corroborating distinctions previously suggested based on morphological differences [43,48,51,63]. Intra-specific morphological variation and genetic divergence are not only associated with genetic drift but also with geographical and ecophenotypic factors [59,65]. The observation of the full range of morphological variation in Reteporella and other erect bryozoans is limited by destructive sampling methods [4,6,59].…”

Section: The Genus Reteporella In the Azores Diversitysupporting

confidence: 78%

“…The veracity of these genetic divergence levels was verified by two independent rounds of sequencing for both mitochondrial markers, all resulting in good quality sequences, confirming the genetic distinctiveness of this specimen. Ecological surveys to characterize the habitat at 150 m around Flores and to obtain more samples similar to BRY16 are necessary to clarify whether this constitutes a distinct lineage of R. atlantica or if it is just a product of natural genetic drift in the population [65]. Population genetic studies are needed to clarify the diversity and distribution of R. atlantica in the Azores.…”

Section: The Genus Reteporella In the Azores Diversitymentioning

confidence: 99%

Morphospecies and molecular diversity of ‘lace corals’: the genus Reteporella (Bryozoa: Cheilostomatida) in the central North Atlantic Azores Archipelago

et al. 2022

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Background As in most bryozoans, taxonomy and systematics of species in the genus Reteporella Busk, 1884 (family Phidoloporidae) has hitherto almost exclusively been based on morphological characters. From the central North Atlantic Azores Archipelago, nine Reteporella species have historically been reported, none of which have as yet been revised. Aiming to characterise the diversity and biogeographic distribution of Azorean Reteporella species, phylogenetic reconstructions were conducted on a dataset of 103 Azorean Reteporella specimens, based on the markers cytochrome C oxidase subunit 1, small and large ribosomal RNA subunits. Morphological identification was based on scanning electron microscopy and complemented the molecular inferences. Results Our results reveal two genetically distinct Azorean Reteporella clades, paraphyletic to eastern Atlantic and Mediterranean taxa. Moreover, an overall concordance between morphological and molecular species can be shown, and the actual bryozoan diversity in the Azores is greater than previously acknowledged as the dataset comprises three historically reported species and four putative new taxa, all of which are likely to be endemic. The inclusion of Mediterranean Reteporella specimens also revealed new species in the Adriatic and Ligurian Sea, whilst the inclusion of additional phidoloporid taxa hints at the non-monophyly of the genus Reteporella. Conclusion Being the first detailed genetic study on the genus Reteporella, the high divergence levels inferred within the genus Reteporella and family Phidoloporidae calls for the need of further revision. Nevertheless, the overall concordance between morphospecies and COI data suggest the potential adequacy of a 3% cut-off to distinguish Reteporella species. The discovery of new species in the remote Azores Archipelago as well as in the well-studied Mediterranean Sea indicates a general underestimation of bryozoan diversity. This study constitutes yet another example of the importance of integrative taxonomical approaches on understudied taxa, contributing to cataloguing genetic and morphological diversity.

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“…Members of the colonial phylum Bryozoa have played a fundamental role in classical debates regarding tempo and mode of morphological evolution (Cheetham, 1986a(Cheetham, , 1986b(Cheetham, , 1987Cheetham et al, 1993Cheetham et al, , 1994Voje et al, 2020), and represent an emerging model system in macroevolutionary, ecological, and paleobiological research (Clark et al, 2010;Di Martino & Liow, 2021Liow et al, 2017;Liow & Taylor, 2019;O'Dea & Jackson, 2009, 2002O'Dea & Okamura, 2000;Okamura et al, 2013). Bryozoans have an old (Cambrian) (Zhang et al, 2021), species-rich (>22,000 described species), and high temporal resolution fossil record (Taylor, 2020).…”

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confidence: 99%

DeepBryo: a web app for AI-assisted morphometric characterization of cheilostome bryozoans

Martino

Berning²,

Gordon

et al. 2022

Preprint

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Bryozoans are becoming an increasingly popular study system in macroevolutionary, ecological, and paleobiological research. Members of this colonial invertebrate phylum are notable for displaying an exceptional degree of division of labor in the form of specialized modules (polymorphs), which allow for the inference of individual allocation of resources to reproduction, defense, and growth using simple morphometric tools. However, morphometric characterizations of bryozoans are notoriously labored, due to the high number of structures often captured per image, as well as the need for specialized knowledge necessary for classifying individual skeletal structures within those images. We here introduce DeepBryo, a web application for deep learning-based morphometric characterization of cheilostome bryozoans. DeepBryo requires a single image as input and performs measurements automatically using instance segmentation algorithms. DeepBryo is capable of detecting objects belonging to six classes and outputting fourteen morphological shape measurements for each object based on the inferred segmentation maps. The users can visualize the predictions, check for errors, and directly filter model outputs on the web browser. Measurements can then be downloaded as a comma-separated values file. DeepBryo has been trained and validated on a total of 72,412 structures, belonging to six different object classes in 935 SEM images of cheilostome bryozoans belonging to 109 different families. The model shows high (>0.8) recall and precision for zooid-level structures. Its misclassification rate is low (~4%) and largely concentrated in a single object class (opesia). The model's estimated structure-level area, height, and width measurements are statistically indistinguishable from those obtained via manual annotation (r2 varying from 0.89 to 0.98) and show no detectable bias. DeepBryo reduces the person-hours required for characterizing the zooids in individual colonies to less than 1% of the time required for manual annotation at no significant loss of measurement accuracy. Our results indicate that DeepBryo enables cost-, labor,- and time-efficient morphometric characterization of cheilostome bryozoans. DeepBryo can greatly increase the scale of macroevolutionary, ecological, taxonomic, and paleobiological analyses, as well as the accessibility of deep learning tools for this emerging model system. Finally, DeepBryo provides the building blocks necessary for adapting the current application to other study groups.

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Revisiting a Landmark Study System: No Evidence for a Punctuated Mode of Evolution inMetrarabdotos

Cited by 12 publications

References 85 publications

Trait–fitness associations do not predict within-species phenotypic evolution over 2 million years

Trait–fitness associations do not predict within-species phenotypic evolution over 2 million years

Morphospecies and molecular diversity of ‘lace corals’: the genus Reteporella (Bryozoa: Cheilostomatida) in the central North Atlantic Azores Archipelago

DeepBryo: a web app for AI-assisted morphometric characterization of cheilostome bryozoans

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