Science, Journal Year: 2023, Volume and Issue: 380(6645)
Published: May 11, 2023
Jensen et al. (1) question evidence presented of a chambered heart within placoderms, citing its small size and apparently ventral atrium. However, they fail to note the belly-up orientation placoderm one nodule, variability morphology extant taxa. Thus, we remain confident in our interpretation mineralized organ as heart.
Language: Английский
Paleobiology, Journal Year: 2024, Volume and Issue: 50(2), P. 271 - 284
Published: March 14, 2024
Abstract The Paleozoic represents a key time interval in the origins and early diversification of chondrichthyans (cartilaginous fishes), but their diversity macroevolution are largely obscured by heterogenous spatial temporal sampling. predominantly cartilaginous skeletons pose an additional limitation on preservation potential hence quality fossil record. Here, we use newly compiled genus-level dataset application sampling standardization methods to analyze global total-chondrichthyan dynamics through from first appearance Ordovician end Permian. Subsampled estimates chondrichthyan genus richness were initially low Silurian increased substantially Early Devonian. Richness reached its maximum middle Carboniferous before dropping across Carboniferous/Permian boundary gradually decreasing throughout Sampling is higher both Devonian compared with most Permian stages. Shark-like scales too limited allow for some subsampling techniques. Our results detect two radiations diversity: earliest Devonian, led acanthodians (stem-group chondrichthyans), which then decline rapidly Late second Carboniferous, holocephalans, increase greatly Devonian/Carboniferous boundary. Dispersal chondrichthyans, specifically into deeper-water environments may reflect niche expansion following faunal displacement aftermath Hangenberg extinction event at
Language: Английский
Citations
2
Palaeontology, Journal Year: 2022, Volume and Issue: 65(4)
Published: July 1, 2022
Abstract Acanthodians are a poorly understood paraphyletic grade of extinct Palaeozoic fishes. They play an increasingly prominent role in our understanding vertebrate evolution as part the chondrichthyan stem‐group even though their evolutionary history is scarce. The limited preservation mostly cartilaginous skeleton largely results bias towards isolated remains such fin spines and scales. Here, we quantify quality acanthodian fossil record by using variation Skeletal Completeness Metric (SCM), approach that calculates how complete skeletons individuals compared to theoretical skeleton. A novel Soft Tissue (STCM) introduced estimate percentage soft body tissue preserved alternate measurement completeness. scores for >1600 specimens comprising >300 taxa obtained from museum collection visits literature surveys were assembled into database. Acanthodian completeness peaks Lower–Middle Devonian, Pennsylvanian, earliest Permian. There no correlation between taxonomic richness show significantly lower distribution than many tetrapod groups, but similarly low bats. Skeletons deposited freshwater more marine environments where sea level negatively correlates with observed Our assessment reveals only weak spatial biases influencing while environmental much higher. This quantified evaluation acanthodians provides foundation further assessments likely influence character absences morphological datasets on estimates early and, therefore, gnathostome evolution.
Language: Английский
Citations
9
Proceedings of the Royal Society B Biological Sciences, Journal Year: 2022, Volume and Issue: 289(1985)
Published: Oct. 19, 2022
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 biases acting on actinopterygian fossil record. Here, we palaeogeographic trends, reconstruct local richness apply estimation techniques to a recently assembled occurrence database for fishes. We identify substantial record biases, such as geographical bias sampling centred around Europe North America. Similarly, estimates skewed by extreme unevenness distributions, reflecting historical taxonomic practices, extent that evenness has an overriding effect estimates. Other than genuine rise Tournaisian end-Devonian mass extinction, actinopterygians appear lack biological signal, heavily biased highly dependent sampling. Increased represented regions expanding beyond literature include museum collection data will be critical obtaining accurate diversity. In conjunction, applying well-sampled regional subsets ‘global’ dataset may trends.
Language: Английский
Citations
8
EarthArXiv (California Digital Library), Journal Year: 2024, Volume and Issue: unknown
Published: Aug. 2, 2024
Animals with multi-element skeletons, including the vertebrates, echinoderms, and arthropods, are some of most biodiverse ecologically important animal groups. Understanding relative impact myriad geological biological factors which on quality skeletal fossils is thus crucial for disentangling perceived changes in biodiversity through time shedding light gaps fossil record. We have characterised specimen-level taphonomic history virtually entire Palaeozoic record echinoids, class echinoderms includes living sea urchins. find that majority this consists disarticulated elements as preservational increases, so does proportion specimens can be identified higher taxonomic precision. then assessed impacts multiple our specimen quality, identifying fine-grained host matrix, well siliciclastic lithology biggest determining echinoid preservation, while aspects intrinsic to specific groups also play a role. Differential sampling seems little role influencing distribution grades, fluctuations North American Siliciclastic rocks positively correlated grades. Our results highlight controlling macrofossil varied, interplay between these variables, grade, precision ability use understand macroevolution.
Language: Английский
Citations
1
Royal Society Open Science, Journal Year: 2024, Volume and Issue: 11(1)
Published: Jan. 1, 2024
Chondrichthyes (sharks, rays, ratfish and their extinct relatives) originated diversified in the Palaeozoic but are rarely preserved as articulated or partly remains because of predominantly cartilaginous endoskeletons. Consequently, evolutionary history is perceived to be documented by isolated teeth, scales fin spines. Here, we aim capture analyse quality chondrichthyan fossil record using a variation skeletal completeness metric, which calculates how complete skeletons individuals compared estimates original entirety. Notably, significantly lower than any published vertebrate group: low throughout Silurian Permian peaking Devonian Carboniferous. Scores increase range similar pelycosaurs parareptiles only when taxa identified solely from spines excluded. We argue that environmental influences probably played an important role completeness. Sea level negatively correlates with records resembles patterns already evident ichthyosaurs, plesiosaurs sauropodomorphs. Such observed variations highlight impact different sampling biases on need acknowledge these inferring macroevolution.
Language: Английский
Citations
1
Biological reviews/Biological reviews of the Cambridge Philosophical Society, Journal Year: 2022, Volume and Issue: 98(1), P. 284 - 315
Published: Oct. 3, 2022
ABSTRACT Actinopterygii makes up half of living vertebrate diversity, and study fossil members during their Palaeozoic rise to dominance has a long history descriptive work. Although research interest into actinopterygians increased in recent years, broader patterns diversity dynamics remain critically understudied. Past studies have investigated macroevolutionary trends piecemeal fashion, variably using existing compendia vertebrates or literature‐based searches. Here, we present comprehensive occurrence‐based dataset spanning the whole Palaeozoic. We use this produce first through‐Palaeozoic genus species counts for Actinopterygii. Diversity through time generally tracks metrics sampling, while major taxonomic problems pervading actinopterygian record obscure trends. Many described are concentrated several particularly problematic ‘waste‐basket’ genera, hiding considerable morphological diversity. This confusion also feeds limited understanding phylogenetic relationships. A heavy sampling bias towards Europe North America exists both occurrence databases available matrices, with other regions underrepresented despite yielding important data. Scrutiny extent which spatial biases influence is lacking, as on forms bias. Low richness some periods may be linked geological biases, effects taphonomic not yet been investigated. Efforts already underway redescribe poorly defined taxa describe from regions, helping address issues accuracy New methods standardisation utilising up‐to‐date will critical teasing apart biological changes those resulting Lastly, continued work enable comparative elucidate origins biogeography subsequent radiation throughout dominate aquatic faunas.
Language: Английский
Citations
6
Proceedings of the Royal Society B Biological Sciences, Journal Year: 2023, Volume and Issue: 290(2004)
Published: Aug. 9, 2023
Analyses of morphological disparity can incorporate living and fossil taxa to facilitate the exploration how phenotypic variation changes through time. However, taphonomic processes introduce non-random patterns data loss in their impact on perceptions is unclear. To address this, we characterize measures change when simulated empirical are degraded random structured loss. We demonstrate that both types distort clades, magnitude direction these varies between most commonly employed distance metrics indices. The inclusion extant exceptionally preserved fossils mitigates distortions clarifies full extent lost, which would otherwise go uncharacterized. This facilitates use ancestral state estimation evolutionary simulations further control for effects Where addition such reference not possible, urge caution extrapolation general from datasets subsets phenotype, may represent no more than traits they sample.
Language: Английский
Citations
3
Springer eBooks, Journal Year: 2024, Volume and Issue: unknown, P. 521 - 597
Published: Jan. 1, 2024
Language: Английский
Citations
0
Science, Journal Year: 2023, Volume and Issue: 380(6645)
Published: May 11, 2023
Jensen et al. (1) question evidence presented of a chambered heart within placoderms, citing its small size and apparently ventral atrium. However, they fail to note the belly-up orientation placoderm one nodule, variability morphology extant taxa. Thus, we remain confident in our interpretation mineralized organ as heart.
Language: Английский
Citations
0