Proceedings of the Royal Society B: Biological Sciences最新文献_第6页

Parasite spillover rather than niche expansion explains infection of host brain by diplostomid eye flukes.

IF 3.8 1区生物学

Proceedings of the Royal Society B: Biological Sciences Pub Date : 2025-02-01 Epub Date: 2025-02-05 DOI: 10.1098/rspb.2024.2648

Alfonso Diaz-Suarez, Veljo Kisand, Siim Kahar, Riho Gross, Anti Vasemägi, Kristina Noreikiene

{"title":"Parasite spillover rather than niche expansion explains infection of host brain by diplostomid eye flukes.","authors":"Alfonso Diaz-Suarez, Veljo Kisand, Siim Kahar, Riho Gross, Anti Vasemägi, Kristina Noreikiene","doi":"10.1098/rspb.2024.2648","DOIUrl":"10.1098/rspb.2024.2648","url":null,"abstract":"Parasites often occupy specific sites within their host, which has important implications for host performance and parasite transmission. Nonetheless, parasitic infections can occur beyond their typical location within a host, significantly altering host-parasite interactions. Yet, the causes behind the atypical tissue tropism are poorly understood. Here, we focus on a ubiquitous group of diplostomid parasites that form diverse communities in fish eyes. We used targeted DNA metabarcoding (cytochrome c oxydase subunit 1, COX1, 250 bp) to evaluate potential mechanisms underlying eye parasite atypical tissue tropism to the brain of two widespread fish species (Eurasian perch and common roach). We found that the most common eye-infecting species (Tylodelphys clavata, Diplostomum baeri) are present in the brains of perch but not in roach. The bipartite network comprising 5 species and 24 mitochondrial haplotypes revealed no brain-specific haplotypes, indicating an apparent lack of genetic divergence between brain- and eye-infecting parasites. Instead, the prevalence, intensity and diversity of eye infections were positively correlated with brain infections. Thus, our results suggest that the most parsimonious mechanism underlying brain infection is density-dependent spillover rather than parasite divergence-driven niche expansion. We anticipate that 'off-target' infections are likely to be severely underestimated in nature with important ecological, evolutionary and medical implications.","PeriodicalId":20589,"journal":{"name":"Proceedings of the Royal Society B: Biological Sciences","volume":"292 2040","pages":"20242648"},"PeriodicalIF":3.8,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11793966/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143189696","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Poverty is associated with both risk avoidance and risk taking: empirical evidence for the desperation threshold model from the UK and France.

IF 3.8 1区生物学

Proceedings of the Royal Society B: Biological Sciences Pub Date : 2025-02-01 Epub Date: 2025-02-05 DOI: 10.1098/rspb.2024.2071

Benoît de Courson, Willem E Frankenhuis, Daniel Nettle

{"title":"Poverty is associated with both risk avoidance and risk taking: empirical evidence for the desperation threshold model from the UK and France.","authors":"Benoît de Courson, Willem E Frankenhuis, Daniel Nettle","doi":"10.1098/rspb.2024.2071","DOIUrl":"10.1098/rspb.2024.2071","url":null,"abstract":"In situations of poverty, do people take more or less risk? One hypothesis states that poverty makes people avoid risk, because they cannot buffer against losses, while another states that poverty makes people take risks, because they have little to lose. Each hypothesis has some previous empirical support. Here, we test the 'desperation threshold' model, which integrates both hypotheses. We assume that people attempt to stay above a critical level of resources, representing their 'basic needs'. Just above this threshold, people have much to lose and should avoid risk. Below, they have little to lose and should take risks. We conducted preregistered tests of the model using survey data from 472 adults in France and the UK. The predictor variables were subjective and objective measures of current resources. The outcome measure, risk taking, was measured using a series of hypothetical gambles. Risk taking followed a V-shape against subjective resources, first decreasing and then increasing again as resources reduced. This pattern was not observed for the objective resource measure. We also found that risk taking was more variable among people with fewer resources. Our findings synthesize the split literature on poverty and risk taking, with implications for policy and interventions.","PeriodicalId":20589,"journal":{"name":"Proceedings of the Royal Society B: Biological Sciences","volume":"292 2040","pages":"20242071"},"PeriodicalIF":3.8,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11793957/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143189786","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Neural and sensory basis of homing behaviour in the invasive cane toad, Rhinella marina.

IF 3.8 1区生物学

Proceedings of the Royal Society B: Biological Sciences Pub Date : 2025-02-01 Epub Date: 2025-02-26 DOI: 10.1098/rspb.2025.0045

Daniel A Shaykevich, Daniela Pareja-Mejía, Chloe Golde, Andrius Pašukonis, Lauren A O'Connell

{"title":"Neural and sensory basis of homing behaviour in the invasive cane toad, Rhinella marina.","authors":"Daniel A Shaykevich, Daniela Pareja-Mejía, Chloe Golde, Andrius Pašukonis, Lauren A O'Connell","doi":"10.1098/rspb.2025.0045","DOIUrl":"10.1098/rspb.2025.0045","url":null,"abstract":"The behavioural, sensory and neural bases of vertebrate navigation are primarily described in mammals and birds. While many studies have explored amphibian navigation, none have characterized brain activity associated with navigation in the wild. To address this knowledge gap, we conducted a study on navigation in the cane toad, Rhinella marina. First, we performed a translocation experiment to describe how invasive cane toads in Hawaii navigate home and observed homing following displacements of up to 1 km. Next, we tested the effect of olfactory and magnetosensory manipulations on homing, as these senses are most commonly associated with amphibian navigation. We found that neither ablation alone prevents homing, further supporting that toad navigation is multimodal. Finally, we tested the hypothesis that the medial pallium, the amphibian homologue to the hippocampus, is involved in homing. Our comparisons of neural activity revealed evidence supporting a conservation of neural structures associated with navigation across vertebrates consistent with neural models of amphibian spatial cognition from recent laboratory studies. Our work furthers our evolutionary understanding of spatial behaviour and cognition in vertebrates and lays a foundation for studying the behavioural, sensory and neural bases of navigation in an invasive amphibian.","PeriodicalId":20589,"journal":{"name":"Proceedings of the Royal Society B: Biological Sciences","volume":"292 2041","pages":"20250045"},"PeriodicalIF":3.8,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11858788/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143503751","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Repeated evolution of photoperiodic plasticity by different genetic architectures during recurrent colonizations in a butterfly.

IF 3.8 1区生物学

Proceedings of the Royal Society B: Biological Sciences Pub Date : 2025-02-01 Epub Date: 2025-02-12 DOI: 10.1098/rspb.2024.2195

Anna B Shoshan, Ugo Pindeler, Christopher W Wheat, Karl Gotthard

{"title":"Repeated evolution of photoperiodic plasticity by different genetic architectures during recurrent colonizations in a butterfly.","authors":"Anna B Shoshan, Ugo Pindeler, Christopher W Wheat, Karl Gotthard","doi":"10.1098/rspb.2024.2195","DOIUrl":"10.1098/rspb.2024.2195","url":null,"abstract":"In cases of recurrent colonizations of similar habitats from the same base population, it is commonly expected that repeated phenotypic adaptation is caused by parallel changes in genetic variation. However, it is becoming increasingly clear that similar phenotypic variation may also evolve by alternative genetic pathways. Here, we explore the repeated evolution of photoperiodic plasticity for diapause induction across Swedish populations of the speckled wood butterfly, Pararge aegeria. This species has colonized Scandinavia at least twice, and population genomic results show that one of the candidate regions associated with spatial variation in photoperiodism is situated on the Z-chromosome. Here, we assay hybrid crosses between several populations that differ in photoperiodic plasticity for sex-linked inheritance of the photoperiodic reaction norm. We find that while a cross between more distantly related populations from the two different colonization events shows strong sex-dependent inheritance of photoperiodic plasticity, a cross between two more closely related populations within the oldest colonization range shows no such effect. We conclude that the genotype-phenotype map for photoperiodic plasticity varies across these populations and that similar local phenotypic adaptation has evolved during recurrent colonization events by partly non-parallel genetic changes.","PeriodicalId":20589,"journal":{"name":"Proceedings of the Royal Society B: Biological Sciences","volume":"292 2040","pages":"20242195"},"PeriodicalIF":3.8,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11813577/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143399808","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Touch inhibits cold: non-contact cooling suggests a thermotactile gating mechanism.

IF 3.8 1区生物学

Proceedings of the Royal Society B: Biological Sciences Pub Date : 2025-02-01 Epub Date: 2025-02-12 DOI: 10.1098/rspb.2024.3014

Ivan Ezquerra Romano, Maansib Chowdhury, Patrick Haggard

{"title":"Touch inhibits cold: non-contact cooling suggests a thermotactile gating mechanism.","authors":"Ivan Ezquerra Romano, Maansib Chowdhury, Patrick Haggard","doi":"10.1098/rspb.2024.3014","DOIUrl":"10.1098/rspb.2024.3014","url":null,"abstract":"Skin stimuli reach the brain via multiple neural channels specific for different stimulus types. These channels interact in the spinal cord, typically through inhibition. Inter-channel interactions can be investigated by selectively stimulating one channel and comparing the sensations that result when another sensory channel is or is not concurrently stimulated. Applying this logic to thermal-mechanical interactions proves difficult, because most existing thermal stimulators involve skin contact. We used a novel non-tactile stimulator for focal cooling (9 mm2) by using thermal imaging of skin temperature as a feedback signal to regulate exposure to a dry-ice source. We could then investigate how touch modulates cold sensation by delivering cooling to the human hand dorsum in either the presence or absence of light touch. Across three signal detection experiments, we found that sensitivity to cooling was significantly reduced by touch. This reduction was specific to touch, as it did not occur when presenting auditory signals instead of the tactile input, making explanations based on distraction or attention unlikely. Our findings suggest that touch inhibits cold perception, recalling interactions of touch and pain previously described by Pain Gate Theory.","PeriodicalId":20589,"journal":{"name":"Proceedings of the Royal Society B: Biological Sciences","volume":"292 2040","pages":"20243014"},"PeriodicalIF":3.8,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11813568/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143399810","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Intraspecific divergence within Microcystis aeruginosa mediates the dynamics of freshwater harmful algal blooms under climate warming scenarios.

IF 3.8 1区生物学

Proceedings of the Royal Society B: Biological Sciences Pub Date : 2025-02-01 Epub Date: 2025-02-05 DOI: 10.1098/rspb.2024.2520

Mirte C M Kuijpers, Catherine V Quigley, Nicole C Bray, Wenbo Ding, Jeffrey D White, Sara L Jackrel

{"title":"Intraspecific divergence within Microcystis aeruginosa mediates the dynamics of freshwater harmful algal blooms under climate warming scenarios.","authors":"Mirte C M Kuijpers, Catherine V Quigley, Nicole C Bray, Wenbo Ding, Jeffrey D White, Sara L Jackrel","doi":"10.1098/rspb.2024.2520","DOIUrl":"10.1098/rspb.2024.2520","url":null,"abstract":"Intraspecific biodiversity can have ecosystem-level consequences and may affect the accuracy of ecological forecasting. For example, rare genetic variants may have traits that prove beneficial under future environmental conditions. The cyanobacterium responsible for most freshwater harmful algal blooms worldwide, Microcystis aeruginosa, occurs in at least three types. While the dominant type occurs in eutrophic environments and is adapted to thrive in nutrient-rich conditions, two additional types have recently been discovered that inhabit oligotrophic and eutrophic environments and have genomic adaptations for survival under nutrient limitation. Here, we show that these oligotrophic types are widespread throughout the Eastern USA. By pairing an experimental warming study with gene expression analyses, we found that the eutrophic type may be most susceptible to climate warming. In comparison, oligotrophic types maintained their growth better and persisted longer under warming. As a mechanistic explanation for these patterns, we found that oligotrophic types responded to warming by widespread elevated expression of heat shock protein genes. Reduction of nutrient loading has been a historically effective mitigation strategy for controlling harmful algal blooms. Our results suggest that climate warming may benefit oligotrophic types of M. aeruginosa, potentially reducing the effectiveness of such mitigation efforts. In-depth study of intraspecific variation may therefore improve forecasting for understanding future whole ecosystem dynamics.","PeriodicalId":20589,"journal":{"name":"Proceedings of the Royal Society B: Biological Sciences","volume":"292 2040","pages":"20242520"},"PeriodicalIF":3.8,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11793963/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143189772","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Systematic shifts in the variation among host individuals must be considered in climate-disease theory.

IF 3.8 1区生物学

Proceedings of the Royal Society B: Biological Sciences Pub Date : 2025-02-01 Epub Date: 2025-02-05 DOI: 10.1098/rspb.2024.2515

Joseph R Mihaljevic, David J Páez

{"title":"Systematic shifts in the variation among host individuals must be considered in climate-disease theory.","authors":"Joseph R Mihaljevic, David J Páez","doi":"10.1098/rspb.2024.2515","DOIUrl":"10.1098/rspb.2024.2515","url":null,"abstract":"To make more informed predictions of host-pathogen interactions under climate change, studies have incorporated the thermal performance of host, vector and pathogen traits into disease models to quantify effects on average transmission rates. However, this body of work has omitted the fact that variation in susceptibility among individual hosts affects disease spread and long-term patterns of host population dynamics. Furthermore, and especially for ectothermic host species, variation in susceptibility is likely to be plastic, influenced by variables such as environmental temperature. For example, as host individuals respond idiosyncratically to temperature, this could affect the population-level variation in susceptibility, such that there may be predictable functional relationships between variation in susceptibility and temperature. Quantifying the relationship between temperature and among-host trait variation will therefore be critical for predicting how climate change and disease will interact to influence host-pathogen population dynamics. Here, we use a model to demonstrate how short-term effects of temperature on the distribution of host susceptibility can drive epidemic characteristics, fluctuations in host population sizes and probabilities of host extinction. Our results emphasize that more research is needed in disease ecology and climate biology to understand the mechanisms that shape individual trait variation, not just trait averages.","PeriodicalId":20589,"journal":{"name":"Proceedings of the Royal Society B: Biological Sciences","volume":"292 2040","pages":"20242515"},"PeriodicalIF":3.8,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11793970/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143190101","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Phenological patterns of tropical mountain forest trees across the neotropics: evidence from herbarium specimens. 新热带地区热带山林树木的物候模式：标本馆标本提供的证据。

IF 3.8 1区生物学

Proceedings of the Royal Society B: Biological Sciences Pub Date : 2025-02-01 Epub Date: 2025-02-26 DOI: 10.1098/rspb.2024.2748

J C Ordoñez, C Tovar, B E Walker, J Wheeler, S Ayala-Ruano, K Aguirre-Carvajal, S M McMahon, F Cuesta

{"title":"Phenological patterns of tropical mountain forest trees across the neotropics: evidence from herbarium specimens.","authors":"J C Ordoñez, C Tovar, B E Walker, J Wheeler, S Ayala-Ruano, K Aguirre-Carvajal, S M McMahon, F Cuesta","doi":"10.1098/rspb.2024.2748","DOIUrl":"10.1098/rspb.2024.2748","url":null,"abstract":"The flowering phenology of many tropical mountain forest tree species remains poorly understood, including flowering synchrony and its drivers across neotropical ecosystems. We obtained herbarium records for 427 tree species from a long-term monitoring transect on the northwestern Ecuadorian Andes, sourced from the Global Biodiversity Information Facility and the Herbario Nacional del Ecuador. Using machine learning algorithms, we identified flowering phenophases from digitized specimen labels and applied circular statistics to build phenological calendars across six climatic regions within the neotropics. We found 47 939 herbarium records, of which 14 938 were classified as flowering by Random Forest Models. We constructed phenological calendars for six regions and 86 species with at least 20 flowering records. Phenological patterns varied considerably across regions, among species within regions, and within species across regions. There was limited interannual synchronicity in flowering patterns within regions primarily driven by bimodal species whose flowering peaks coincided with irradiance peaks. The predominantly high variability of phenological patterns among species and within species likely confers adaptative advantages by reducing interspecific competition during reproductive periods and promoting species coexistence in highly diverse regions with little or no seasonality.","PeriodicalId":20589,"journal":{"name":"Proceedings of the Royal Society B: Biological Sciences","volume":"292 2041","pages":"20242748"},"PeriodicalIF":3.8,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11858787/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143503755","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The role of stochasticity in fungal community assembly: explaining apparent stochasticity with field experiments.

IF 3.8 1区生物学

Proceedings of the Royal Society B: Biological Sciences Pub Date : 2025-02-01 Epub Date: 2025-02-05 DOI: 10.1098/rspb.2024.2416

Nerea Abrego, Sonja Saine, Reijo Penttilä, Brendan Furneaux, Tuija Hytönen, Otto Miettinen, Norman Monkhouse, Raisa Mäkipää, Jorma Pennanen, Evgeny V Zakharov, Otso Ovaskainen

{"title":"The role of stochasticity in fungal community assembly: explaining apparent stochasticity with field experiments.","authors":"Nerea Abrego, Sonja Saine, Reijo Penttilä, Brendan Furneaux, Tuija Hytönen, Otto Miettinen, Norman Monkhouse, Raisa Mäkipää, Jorma Pennanen, Evgeny V Zakharov, Otso Ovaskainen","doi":"10.1098/rspb.2024.2416","DOIUrl":"https://doi.org/10.1098/rspb.2024.2416","url":null,"abstract":"Stochasticity is a main process in community assembly. However, experimental studies rarely target stochasticity in natural communities, and hence experimental validation of stochasticity estimates in observational studies is lacking. Here, we combine experimental and observational data to unravel the role of stochasticity in the assembly of wood-inhabiting fungi. We carried out a replicated field experiment where the natural colonization of a focal fungal species was simulated through inoculation, and the local fungal communities were monitored through DNA metabarcoding before and after the inoculations. The amount of stochasticity in fungal colonization was less pronounced than expected from the amount of unpredictability in observational data, suggesting that stochasticity may play a smaller role in fungal occurrence than previously anticipated, or that it may be a stronger influence in the dispersal and establishment phases than in colonization per se. Stochasticity was more prominent in the initial phase of community succession, with the earliest successional stage involving a higher level of stochasticity than the later stage after 2 years. We conclude that experimentally measuring the role of stochasticity in community assembly is feasible for species-rich communities under natural conditions and highlight the importance of experimentally testing the accuracy of stochasticity estimates based on observational data.","PeriodicalId":20589,"journal":{"name":"Proceedings of the Royal Society B: Biological Sciences","volume":"292 2040","pages":"20242416"},"PeriodicalIF":3.8,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143190286","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Cambrian carbonaceous protoconodonts and the early fossil record of the Chaetognatha.

IF 3.8 1区生物学

Proceedings of the Royal Society B: Biological Sciences Pub Date : 2025-02-01 Epub Date: 2025-02-19 DOI: 10.1098/rspb.2024.2386

Ben J Slater

{"title":"Cambrian carbonaceous protoconodonts and the early fossil record of the Chaetognatha.","authors":"Ben J Slater","doi":"10.1098/rspb.2024.2386","DOIUrl":"10.1098/rspb.2024.2386","url":null,"abstract":"Fossil remains from the early Cambrian Period suggest an ancient origin for the phylum Chaetognatha. As macrofossils, Cambrian chaetognaths are restricted to just a few Konservat-Lagerstätten sites, yet the dispersed grasping spines characteristic of this clade are relatively common as phosphatized 'protoconodonts'. Here, an abundance of protoconodonts are described, but preserved in an entirely different manner, as 'small carbonaceous fossils' (SCFs) extracted from Cambrian Fortunian and Stage 4 mudrocks of Estonia and Sweden, respectively. Preservation among small carbonaceous fossils is substantial, representing an alternative but overlooked resource for tracing the origins of the chaetognath clade. Importantly, small carbonaceous fossils are abundant in normal marine siliciclastic deposits, in which conventionally studied phosphatic protoconodont fossils are scarce. Recent advances in constraining the phylogenetic position of chaetognaths suggest a relationship to the clade Gnathifera (gnathostomulids, micrognathozoans, rotifers). Newly emerging small carbonaceous fossil records, therefore, offer the chance to establish important calibration points for the divergence of deep bilaterian clades, including Protostomia, Lophotrochozoa and Gnathifera. Protoconodonts are especially valuable in this respect given their appearance close to, or prior to, the Ediacaran-Cambrian boundary. A first compilation of small carbonaceous fossil protoconodont records suggests chaetognath-like bilaterians had evolved by the latest Ediacaran (approximately 555-545 Ma), while the jaw complex possessed by the chaetognath crown-group emerged at least 520 Ma.","PeriodicalId":20589,"journal":{"name":"Proceedings of the Royal Society B: Biological Sciences","volume":"292 2041","pages":"20242386"},"PeriodicalIF":3.8,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11836706/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143449878","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0