Ovipositor and mouthparts in a fossil insect support a novel ecological role for early orthopterans in 300 million years old forests.
Ontology highlight
ABSTRACT:
SUBMITTER: Chen L
PROVIDER: S-EPMC8631945 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:Background:Biological diversity is a hot topic in current research, especially its observed decrease in modern times. Investigations of past ecosystems offer additional insights to help better understand the processes underlying biodiversity. The Cretaceous period is of special interest in this context, especially with respect to arthropods. During that period, representatives of many modern lineages appeared for the first time, while representatives of more ancient groups also co-occurred. At the same time, side branches of radiating groups with 'experimental morphologies' emerged that seemed to go extinct shortly afterwards. However, larval forms, with their morphological diversity, are largely neglected in such studies, but may provide important insights into morphological and ecological diversity and its changes in the past. Results:We present here a new fossil insectan larva, a larval lacewing, in Cretaceous amber, exhibiting a rather unusual, 'experimental' morphology. The specimen possesses extremely large (in relation to body size) mandibulo-maxillary piercing stylets. Additionally, the labial palps are very long and are subdivided into numerous elements, overall appearing antenniform. In other aspects, the larva resembles many other neuropteran-type larvae. Conclusions:We provide a comparison that includes quantitative aspects of different types of neuropteran larvae to emphasise the exceptionality of the new larva, and discuss its possible relationships to known lineages of Neuroptera; possible interpretations are closer relationships to Dilaridae or Osmylidae. In any case, several of the observed characters must have evolved convergently. With this new find, we expand the known morphological diversity of neuropterans in the Cretaceous fauna.
| S-EPMC6716810 | biostudies-literature
Project description:Direct evidence of paleo-parasitism in crustaceans is very scarce. Epicaridean isopods are obligatory parasites of crustaceans, including decapods such as crabs, shrimps, and lobsters. Their interaction with hosts is known from fossils as far back as the Jurassic through deformations of the branchial cuticle on the hosts. Their small size and low fossilization potential, outside of those larvae that have been found in amber, makes understanding the group's evolution challenging. Here, we report the oldest evidence of paleo-parasitism in marine shrimps and an imprint of a putative adult parasite that appears to be an epicaridean isopod. Our results suggest that the parasite-host interaction between epicaridean isopods and marine shrimps started at least 110 million years ago, and the Tethys Sea was a possible dispersal pathway for this lineage of parasites during the Jurassic and Cretaceous, as known for other marine organisms through most of the Mesozoic and Cenozoic. The oldest fossil records of bopyrid swellings associated with a large number of decapods from the Jurassic in Europe suggest that the Tethys region was a center of epicaridean distribution as a whole. Recent parasitic isopods found on dendrobranchiate shrimps are restricted to the Indo-Pacific and may represent a relict group of a lineage of parasites more widely distributed in the Mesozoic.
| S-EPMC10477257 | biostudies-literature
Project description:Microsatellites are short, repetitive DNA sequences that can rapidly expand and contract due to slippage during DNA replication. Despite their impacts on transcription, genome structure, and disease, relatively little is known about the evolutionary dynamics of these short sequences across long evolutionary periods. To address this gap in our knowledge, we performed comparative analyses of 304 available insect genomes. We investigated the impact of sequence assembly methods and assembly quality on the inference of microsatellite content, and we explored the influence of chromosome type and number on the tempo and mode of microsatellite evolution across one of the most speciose clades on the planet. Diploid chromosome number had no impact on the rate of microsatellite evolution or the amount of microsatellite content in genomes. We found that centromere type (holocentric or monocentric) is not associated with a difference in the amount of microsatellite content; however, in those species with monocentric chromosomes, microsatellite content tends to evolve faster than in species with holocentric chromosomes.
| S-EPMC7464534 | biostudies-literature
Project description:Fossilized leaves provide the longest running record of hyperdiverse plant-insect herbivore associations. Reconstructions of these relationships over deep time indicate strong links between environmental conditions, herbivore diversity, and feeding damage on leaves. However, herbivory has not been compared between the past and the modern era, which is characterized by intense anthropogenic environmental change. Here, we present estimates for damage frequencies and diversities on fossil leaves from the Late Cretaceous (66.8 Ma) through the Pleistocene (2.06 Ma) and compare these estimates with Recent (post-1955) leaves collected via paleobotanical methods from modern ecosystems: Harvard Forest, United States; the Smithsonian Environmental Research Center, United States; and La Selva, Costa Rica. Total damage frequency, measured as the percentage of leaves with any herbivore damage, within modern ecosystems is greater than any fossil locality within this record. This pattern is driven by increased frequencies across nearly all functional feeding groups within the Recent. Diversities of total, specialized, and mining damage types are elevated within the Recent compared with fossil floras. Our results demonstrate that plants in the modern era are experiencing unprecedented levels of insect damage, despite widespread insect declines. Human influence, such as the rate of global climate warming, influencing insect feeding and timing of life cycle processes along with urbanization and the introduction of invasive plant and insect species may drive elevated herbivory. This research suggests that the strength of human influence on plant-insect interactions is not controlled by climate change alone but rather, the way in which humans interact with terrestrial landscape.
| S-EPMC9586316 | biostudies-literature
Project description:With millions of extant species, ecdysozoans (Scalidophora, Nematoida and Panarthropoda) constitute a major portion of present-day biodiversity. All ecdysozoans secrete an exoskeletal cuticle which must be moulted periodically and replaced by a larger one. Although moulting (ecdysis) has been recognized in early Palaeozoic panarthropods such as trilobites and basal groups such as anomalocaridids and lobopodians, the fossil record lacks clear evidence of ecdysis in early scalidophorans, largely because of difficulties in recognizing true exuviae. Here, we describe two types of exuviae in microscopic scalidophoran worms from the lowermost Cambrian Kuanchuanpu Formation ( ca 535 Ma) of China and reconstruct their moulting process. These basal scalidophorans moulted in a manner similar to that of extant priapulid worms, extricating themselves smoothly from their old tubular cuticle or turning their exuviae inside out like the finger of a glove. This is the oldest record of moulting in ecdysozoans. We also discuss the origin of ecdysis in the light of recent molecular analyses and the significance of moulting in the early evolution of animals.
| S-EPMC6650709 | biostudies-literature
Project description:Sex-determination mechanisms vary greatly among taxa. It has been proposed that genetic sex-determination pathways evolve in reverse order from the final step in the pathway to the first step. Consistent with this hypothesis, doublesex (dsx), the most downstream gene in the Drosophila sex-determination cascade that determines most sexual phenotypes also determines sex in other dipterans and the silk moth, while the upstream genes vary among these species. However, it is unknown when dsx was recruited to the sex-determination pathway during insect evolution. Furthermore, sex-specific splicing of dsx, by which dsx determines sex, is different in pattern and mechanism between the moth and the fly, raising an interesting question of how these insects have kept the executor of sex determination while allowing flexibility in the means of execution. To address these questions, here we study the dsx gene of the honeybee Apis mellifera, a member of the most basal lineage of holometabolous insects. We report that honeybee dsx is sex-specifically spliced and that it produces both the fly-type and moth-type splicing forms, indicating that the use of different splicing forms of Dsx in controlling sexual differentiation was present in the common ancestor of holometabolous insects. Our data suggest that in ancestral holometabolous insects the female Dsx form is the default and the male form is generated by suppressing the splicing of the female form. Thus, it is likely that the dsx splicing activator system in flies, where the male form is the default, arose during early dipteran evolution.
| S-EPMC2147941 | biostudies-literature
Project description:Spiders are an important animal group, with a long history. Details of their origins remain limited, with little knowledge of their stem group, and no insights into the sequence of character acquisition during spider evolution. We describe a new fossil arachnid, Idmonarachne brasierigen. et sp. nov. from the Late Carboniferous (Stephanian,ca 305-299 Ma) of Montceau-les-Mines, France. It is three-dimensionally preserved within a siderite concretion, allowing both laboratory- and synchrotron-based phase-contrast computed tomography reconstruction. The latter is a first for siderite-hosted fossils and has allowed us to investigate fine anatomical details. Although distinctly spider-like in habitus, this remarkable fossil lacks a key diagnostic character of Araneae: spinnerets on the underside of the opisthosoma. It also lacks a flagelliform telson found in the recently recognized, spider-related, Devonian-Permian Uraraneida. Cladistic analysis resolves our new fossil as sister group to the spiders: the spider stem-group comprises the uraraneids and I. brasieri While we are unable to demonstrate the presence of spigots in this fossil, the recovered phylogeny suggests the earliest character to evolve on the spider stem-group is the secretion of silk. This would have been followed by the loss of a flagelliform telson, and then the ability to spin silk using spinnerets. This last innovation defines the true spiders, significantly post-dates the origins of silk, and may be a key to the group's success. The Montceau-les-Mines locality has previously yielded a mesothele spider (with spinnerets). Evidently, Late Palaeozoic spiders lived alongside Palaeozoic arachnid grades which approached the spider condition, but did not express the full suite of crown-group autapomorphies.
| S-EPMC4822468 | biostudies-literature
Project description:Living cartilaginous fishes, or chondrichthyans, include numerous elasmobranch (sharks and rays) species but only few chimaeroid (ratfish) species. The early history of chimaeroids, or holocephalans, and the modalities of their divergence from elasmobranchs are much debated. During Carboniferous times, 358-300 million years (Myr) ago, they underwent a remarkable evolutionary radiation, with some odd and poorly understood forms, including the enigmatic iniopterygians that were known until now from poorly informative flattened impressions. Here, we report iniopterygian skulls found preserved in 3 dimensions in approximately 300-Myr-old concretions from Oklahoma and Kansas. The study was performed by using conventional X-ray microtomography (muCT), as well as absorption-based synchrotron microtomography (SR-muCT) [Tafforeau P, et al. (2006) Applications of X-ray synchrotron microtomography for non-destructive 3D studies of paleontological specimens. Appl Phys A 83:95-202] and a new holotomographic approach [Guigay P, Langer M, Boistel R, Cloetens P (2007) Mixed transfer function and transport of intensity approach for phase retrieval in the Fresnel region. Opt Lett 32:1617-1619], which revealed their peculiar anatomy. Iniopterygians also share unique characters with living chimaeroids, suggesting that the key chimaeroid skull features were already established 300 Myr ago. Moreover, SR-muCT of an articulated skull revealed a strikingly brain-shaped structure inside the endocranial cavity, which seems to be an exceptional case of soft-tissue mineralization of the brain, presumably as a result of microbially induced postmortem phosphatization. This was imaged with exceptional accuracy by using holotomography, which demonstrates its great potential to image preserved soft parts in dense fossils.
| S-EPMC2653559 | biostudies-literature
Project description:Salamanders are the only tetrapods capable of fully regenerating their limbs throughout their entire lives. Much data on the underlying molecular mechanisms of limb regeneration have been gathered in recent years allowing for new comparative studies between salamanders and other tetrapods that lack this unique regenerative potential. By contrast, the evolution of animal regeneration just recently shifted back into focus, despite being highly relevant for research designs aiming to unravel the factors allowing for limb regeneration. We show that the 300-million-year-old temnospondyl amphibian Micromelerpeton, a distant relative of modern amphibians, was already capable of regenerating its limbs. A number of exceptionally well-preserved specimens from fossil deposits show a unique pattern and combination of abnormalities in their limbs that is distinctive of irregular regenerative activity in modern salamanders and does not occur as variants of normal limb development. This demonstrates that the capacity to regenerate limbs is not a derived feature of modern salamanders, but may be an ancient feature of non-amniote tetrapods and possibly even shared by all bony fish. The finding provides a new framework for understanding the evolution of regenerative capacity of paired appendages in vertebrates in the search for conserved versus derived molecular mechanisms of limb regeneration.
| S-EPMC4211449 | biostudies-literature
Project description:The 520 million-year-old Chengjiang biota of China (UNESCO World Heritage) presents the earliest known evidence of the so-called Cambrian Explosion. Studies, however, have mainly been limited to the information exposed on the surface of the slabs. Thus far, structures preserved inside the slabs were accessed by careful removal of the matrix, in many cases with the unfortunate sacrifice of some "less important" structures, which destroys elements of exceptionally preserved specimens. Here, we show for the first time that microtomography (micro-CT) can reveal structures situated inside a Chengjiang fossil slab without causing any damage. In the present study a trilobitomorph arthropod (Xandarella spectaculum) can be reliably identified only with the application of micro-CT. We propose that this technique is an important tool for studying three-dimensionally preserved Chengjiang fossils and, most likely, also those from other biota with a comparable type of preservation, specifically similar iron concentrations.
| S-EPMC4523851 | biostudies-other