Skeletal and soft tissue completeness of the acanthodian fossil record

Schnetz, Lisa; Butler, Richard J.; Coates, Michael I.; Sansom, Ivan J.

doi:10.1111/pala.12616

Cited by 8 publications

(35 citation statements)

References 110 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Cleary et al ., 2015 ; Tutin & Butler, 2017 ; Driscoll et al ., 2019 ). To date, only one study has investigated completeness in a group of fishes (Schnetz et al ., 2022 ), finding that the acanthodian fossil record is comprised predominantly of isolated remains and is among the least complete vertebrate records (measured as skeletal completeness). Completeness of specimens was significantly higher in freshwater deposits than marine, in contrast to the fossil record of marine tetrapod clades, which appears to be more complete than those of terrestrial tetrapods (Cleary et al ., 2015 ; Tutin & Butler, 2017 ; Driscoll et al ., 2019 ).…”

Section: Challenges To Deciphering the P Alaeozoic...mentioning

confidence: 99%

“…Completeness of specimens was significantly higher in freshwater deposits than marine, in contrast to the fossil record of marine tetrapod clades, which appears to be more complete than those of terrestrial tetrapods (Cleary et al ., 2015 ; Tutin & Butler, 2017 ; Driscoll et al ., 2019 ). Higher completeness in marine tetrapods is attributed to higher sedimentation rates in the marine realm, whereas anoxic conditions and low turbulence are suggested to be responsible for higher freshwater completeness in acanthodians (Schnetz et al ., 2022 ). Quantification of the level of skeletal completeness in actinopterygians will help determine whether completeness of the actinopterygian record exhibits similar traits to the acanthodian or tetrapod records and aid interpretations of the biases acting on the fossil record, especially regarding marine versus freshwater fishes.…”

Section: Challenges To Deciphering the P Alaeozoic...mentioning

confidence: 99%

See 1 more Smart Citation

The early diversification of ray‐finned fishes (Actinopterygii): hypotheses, challenges and future prospects

et al. 2022

View full text Add to dashboard Cite

Actinopterygii makes up half of living vertebrate diversity, and study of fossil members during their Palaeozoic rise to dominance has a long history of descriptive work. Although research interest into Palaeozoic actinopterygians has increased in recent years, broader patterns of diversity and diversity dynamics remain critically understudied. Past studies have investigated macroevolutionary trends in Palaeozoic actinopterygians in a piecemeal fashion, variably using existing compendia of vertebrates or literature‐based searches. Here, we present a comprehensive occurrence‐based dataset of actinopterygians spanning the whole of the Palaeozoic. We use this to produce the first through‐Palaeozoic trends in genus and species counts for Actinopterygii. Diversity through time generally tracks metrics for sampling, while major taxonomic problems pervading the Palaeozoic actinopterygian record obscure diversity trends. Many described species are concentrated in several particularly problematic ‘waste‐basket’ genera, hiding considerable morphological and taxonomic diversity. This taxonomic confusion also feeds into a limited understanding of phylogenetic relationships. A heavy sampling bias towards Europe and North America exists in both occurrence databases and available phylogenetic matrices, with other regions underrepresented despite yielding important data. Scrutiny of the extent to which spatial biases influence the actinopterygian record is lacking, as is research on other forms of bias. Low richness in some time periods may be linked to geological biases, while the effects of taphonomic biases on Palaeozoic actinopterygians have not yet been investigated. Efforts are already underway both to redescribe poorly defined taxa and to describe taxa from underrepresented regions, helping to address taxonomic issues and accuracy of occurrence data. New methods of sampling standardisation utilising up‐to‐date occurrence databases will be critical in teasing apart biological changes in diversity and those resulting from bias. Lastly, continued phylogenetic work will enable the use of phylogenetic comparative methods to elucidate the origins of actinopterygian biogeography and subsequent patterns of radiation throughout their rise to dominate aquatic faunas.

show abstract

Section: Challenges To Deciphering the P Alaeozoic...mentioning

confidence: 99%

Section: Challenges To Deciphering the P Alaeozoic...mentioning

confidence: 99%

The early diversification of ray‐finned fishes (Actinopterygii): hypotheses, challenges and future prospects

et al. 2022

View full text Add to dashboard Cite

show abstract

“…Diversity in these intervals is principally derived from fluvio-lacustrine deposits designated as Lagerstätten [5]. As fossil fish tend to be better preserved in freshwater environments than marine [81], this may translate to easier identification of taxa in freshwater environments, potentially biasing richness measures. While there is no relationship between palaeoenvironment and rank occurrence in the Palaeozoic overall (electronic supplementary material, figure S1), the intervals with the highest frequencies of taxa are those that heavily sample freshwater deposits.…”

Section: Discussionmentioning

confidence: 99%

Sampling biases obscure the early diversification of the largest living vertebrate group

2022

View full text Add to dashboard Cite

Extant ray-finned fishes (Actinopterygii) dominate marine and freshwater environments, yet spatio-temporal diversity dynamics following their origin in the Palaeozoic are poorly understood. Previous studies investigate face-value patterns of richness, with only qualitative assessment of biases acting on the Palaeozoic actinopterygian fossil record. Here, we investigate palaeogeographic trends, reconstruct local richness and apply richness estimation techniques to a recently assembled occurrence database for Palaeozoic ray-finned fishes. We identify substantial fossil record biases, such as geographical bias in sampling centred around Europe and North America. Similarly, estimates of diversity are skewed by extreme unevenness in the occurrence distributions, reflecting historical biases in sampling and taxonomic practices, to the extent that evenness has an overriding effect on diversity estimates. Other than a genuine rise in diversity in the Tournaisian following the end-Devonian mass extinction, diversity estimates for Palaeozoic actinopterygians appear to lack biological signal, are heavily biased and are highly dependent on sampling. Increased sampling of poorly represented regions and expanding sampling beyond the literature to include museum collection data will be critical in obtaining accurate estimates of Palaeozoic actinopterygian diversity. In conjunction, applying diversity estimation techniques to well-sampled regional subsets of the ‘global’ dataset may identify accurate local diversity trends.

show abstract

“…Factor in data loss associated with other biostratinomic processes, and it is perhaps unsurprising that over 70% of fossil character scores are missing in some mammal datasets [54]. These data loss can be even more severe in extinct clades: the average completeness of the skeletal and soft tissue fossil records for acanthodians sits at 14% and 18%, respectively [55]. Our study is similar in approach to that of Lehmann et al [24] but crucially, we introduced much more realistic differences in data loss between our groups of taxa, even if the most extreme differences (77.2% of fossil data versus 0% of extant) were, perhaps, still too conservative.…”

Section: (C) Past Problems and Future Solutionsmentioning

confidence: 99%

Fossilization can mislead analyses of phenotypic disparity

et al. 2023

View full text Add to dashboard Cite

Analyses of morphological disparity can incorporate living and fossil taxa to facilitate the exploration of how phenotypic variation changes through time. However, taphonomic processes introduce non-random patterns of data loss in fossil data and their impact on perceptions of disparity is unclear. To address this, we characterize how measures of disparity change when simulated and empirical data are degraded through random and structured data loss. We demonstrate that both types of data loss can distort the disparity of clades, and that the magnitude and direction of these changes varies between the most commonly employed distance metrics and disparity indices. The inclusion of extant taxa and exceptionally preserved fossils mitigates these distortions and clarifies the full extent of the data lost, most of which would otherwise go uncharacterized. This facilitates the use of ancestral state estimation and evolutionary simulations to further control for the effects of data loss. Where the addition of such reference taxa is not possible, we urge caution in the extrapolation of general patterns in disparity from datasets that characterize subsets of phenotype, which may represent no more than the traits that they sample.

show abstract

Skeletal and soft tissue completeness of the acanthodian fossil record

Cited by 8 publications

References 110 publications

The early diversification of ray‐finned fishes (Actinopterygii): hypotheses, challenges and future prospects

The early diversification of ray‐finned fishes (Actinopterygii): hypotheses, challenges and future prospects

Sampling biases obscure the early diversification of the largest living vertebrate group

Fossilization can mislead analyses of phenotypic disparity

Contact Info

Product

Resources

About