Figure 15 - uploaded by George Poinar
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A phasmatid, Balticophasma sp. (Phasmatodea: Phasmatidae) parasitized by Heydenius phasmatophilus Poinar (2012) in Baltic amber (Scale bar ¼ 2.1 mm).
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This chapter discusses the evolutionary history of nematode parasites of invertebrates, vertebrates and plants based on fossil remains in amber, stone and coprolites dating from the Palaeozoic to the Holocene. The earliest parasitic nematode is a primitive plant parasite from the Devonian. Fossil invertebrate-parasitic nematodes first appeared in t...
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Analysis of specimens preserved in amber from the Cretaceous period suggests that nematodes changed their host preference towards insects with a complete metamorphosis more recently.
Citations
... Recognizable parasitic nematode forms are represented in fossil remains, but reports are sparse [32][33][34][35][36][37][38][39][40][41][42]. There exists enough material, however, to establish their presence within the Mesozoic era, but little in the Paleozoic [34,35]. ...
... Study of Nematodeshave been observed in Precambrian rocks, but clear examples of nematodes are not noted. Reports from the late Mississippian era[37,38] are clearer. Either way, corroboration is scarce. ...
Nematode worms are the most abundant multicellular organism on Earth. They thrive in every habitat known, and they are voracious feeders within the top 70 cm of soils. Their sturdy cuticle protects them from environmental factors and predators. Nematodes play a significant role in the decomposition of vertebrate remains in soil and serve as indicators of nutrients that enter soils during decomposition. Certain parasitic nematodes have been identified in fossil remains, but reports of fossil worms are rare. We demonstrate the abundant presence of opportunistic nematodes feeding within dinosaur bones from the Hell Creek formation, MT. The presence of visible worm ultrastructure indicates that they were alive when preserved within the dinosaur bones. Our findings are identical to worms characterized as “blood parasites” in a dinosaur bone from Brazil, demonstrating that there is sufficient soft tissue within dinosaur bone canals to sustain large populations of nematodes post-mortem.
... Since the memithids normally grow coiled in the body of their host, when outstretched, they are often longer than their host (Poinar & Early, 1990;Poinar, 2001Poinar, , 2015a. Mermithids can also be forced out of their hosts by traumatic events (Poinar, 2015b), as for example, being entrapped in amber (De Baets et al., 2023;Luo et al., 2023). Mermithid parasitism is commonly observed worldwide and has been documented in various ecological groups of spiders (Ko suli c & Ma sov a, 2019). ...
... The detection of mermithids in spiders can be challenging, and their early emergence from hosts often yields immature nematodes (Poinar, 1987(Poinar, , 2011(Poinar, , 2015b. Studies have revealed two primary pathways by which mermithids invade spider hosts (Poinar, 1985(Poinar, , 1987. ...
... The association between pollinating fig wasps and their obligate nematodes is ancient. Dominican amber fossils aged 20-40 million years old (Poinar, 2015) identify a clear association between a female agaonid pollinator wasp and infective-consumptive juvenile nematodes (likely diplogastrid) classified as Syconema dominicana (Fig. 3) (Poinar, 2011). Given this age, it is likely that nematodes were already associated with figs and pollinating fig wasps at the onset of initial radiations out of southeast Asia (see (Cruaud et al., 2012)), which may help to describe their current pantropical distributions (Berg, 1989;Machado et al., 2005). ...
... Bacterivore nematodes are among the most ancient and abundant metazoans in the biosphere (Poinar, 2015;Cobb, 1914;van den Hoogen et al., 2019;Samuel et al., 2016). The nematode Caenorhabditis elegans feeds on a great variety of bacteria from commensals to human pathogens. ...
The inheritance of memory is an adaptive trait. Microbes challenge the immunity of organisms and trigger behavioral adaptations that can be inherited, but how bacteria produce inheritance of a trait is unknown. We use Caenorhabditis elegans and its bacteria to study the transgenerational RNA dynamics of interspecies crosstalk leading to a heritable behavior. A heritable response of C. elegans to microbes is the pathogen-induced diapause (PIDF), a state of suspended animation to evade infection. We identify RsmY, a small RNA involved in quorum sensing in Pseudomonas aeruginosa as a trigger of PIDF. The histone methyltransferase (HMT) SET-18/SMYD3 and the argonaute HRDE-1, which promotes multi-generational silencing in the germline, are also needed for PIDF initiation. The HMT SET-25/EHMT2 is necessary for memory maintenance in the transgenerational lineage. Our work is a starting point to understanding microbiome-induced inheritance of acquired traits, and the transgenerational influence of microbes in health and disease.
... The chance of fossilization of Nematoda/ Platyhelminthes is known to be limited because they have soft bodies. Traces they left over the sediments or the ones preserved in coprolites or in amber are the only known fossils since the Palaeozoic (Poinar 2015). Some Nematoda/Platyhelminthes taxa may have an acid-resistant outer sheath during their growth stage, like the ones recorded here hence fossils may appear in palynological preparations. ...
... Labandeira and Li (2021) used such an approach to efficiently quantify the Mid-Mesozoic Parasitoid Revolution in insects at the family level. Although amber has to some degree been systematically screened for parasitic arthropod and nematode remains (Poinar 2011b(Poinar , 2015a, there is still some way to go to understand the history of unicellular pathogens in amber (Poinar 2021). ...
The fossil record of parasites is limited thus far. A survey of the fossil record shows that some modes of preservation show a higher potential for the preservation of parasitic remains or parasite–host associations than generally recognized. A better understanding of the taphonomy of parasites is critical to better predict their preservation potential and, together with new techniques like computed tomography, can open the door for systematic screening of parasite sources in deep time. Phosphatization seems particularly fruitful to characterize anatomical details for microscopic parasites or pathogens. Amber deposits are rich in terrestrial parasitic ecdysozoans and their pathogens, but their extent does not bracket a single mass extinction. For particular parasite–host associations, preservation of direct evidence is unlikely, but traces they leave in skeletons and other host remains can be used to trace them back to the Mesozoic or even the Paleozoic. Vertebrate coprolites have yielded remains of endoparasites as far back as the Carboniferous, but a more systematic screening of coprolites is necessary to make them a successful source of parasitic remains as for the Quaternary. Parasites with preservable hard parts and/or characteristic pathologies have the best potential to track changes in marine disease prevalence in high resolution across extinction or environmental perturbations, but more studies need to report their sample sizes and prevalences.
... Nematodes have occasionally also been implicated in pearl formation (e.g., Herdman and Hornell 1906). There is no reliable fossil record of nematodes infecting bivalves; however they have been preserved in terrestrial vertebrate coprolites and amber (Boucot and Poinar Jr. 2010;Poinar Jr. 2015;De Baets and Littlewood 2015;De Baets et al. 2021a, c). ...
Parasites are ubiquitous in modern ecosystems, occupy one of the most successful life modes, promote ecosystem stability, and, despite their typically diminutive size and lack of a mineralized skeleton, are commonly identified in the fossil record. Bivalve mollusks have occupied marine aquatic environments since the Cambrian, comprise an excellent fossil record, and often preserve traces of interactions with their parasites. Here we review parasite-host interactions of living bivalves and the record of parasitism of bivalves that reaches as far back as the Silurian. Escalation in parasite-host bivalve interactions seems to have occurred in both the middle Paleozoic and the late Mesozoic to Cenozoic, similar to trends documented in other antagonistic interactions.
... In the Middle Triassic of Germany, the described turbellarians (Platyhelminthes) occur in different parts of the Muschelkalk succession (Knaust 2010), and the putative oldest representatives were recently described from the Upper Ordovician of Anticosti Island, Canada (Knaust & Desrochers 2019). The geological record of nematodes also remains scattered, although free-living and parasitic representatives are reported (see reviews by Poinar 2015;De Baets et al. 2020). Beside occurrences in coprolites (Permian, Triassic) and amber (Cretaceous), sinusoidal trails (Ediacaran-Cambrian, Early Ordovician) were assumed to be produced by nematodes. ...
Exceptionally preserved remains of Platyhelminthes (flatworms) and Nematoda (roundworms) are closely associated with ammonoids, nautiloids and asteroids in Middle Triassic carbonates of the Upper Muschelkalk Group in Germany. Although soft‐bodied organisms occur in different parts of the succession, the reported examples indicate foraging and a possible scavenging relationship of these worms and their benefit from decaying soft parts. This is a rare record of Platyhelminthes and Nematodes, partly preserved at the termination of their traces, which adds to our patchy knowledge of Fossillagerstätten after the end‐Permian mass extinction. It reveals foraging and scavenging worms on decaying soft parts of macrofauna and associated bacteria on a Middle Triassic carbonate mud flat. The composition of the Middle Triassic benthic communities might be remarkably similar to modern mud flats.
... Comparison: Nematodes are common constituents of the Muschelkalk Fossillagerstätte, where they occur within their typical sinusoidal trails (Knaust 2010;Knaust 2020b, and references therein). The geological record of nematodes remains scattered, although free-living and parasitic representatives are reported (see reviews by Poinar 2015 andDe Baets 2021 & Fauchald, 1997? Remarks: Numerous vermiform organisms can be assigned to polychaetes based on their overall shape, segmentation, and bristles. ...
Exceptionally preserved non-biomineralised biota occurs within a single microbialite bed in the Muschelkalk Group of Germany.
Although their internal structures are barely preserved, morphological features allow assignment to various groups of organisms. Many
of the body fossils are preserved as limonitic aggregates within their traces and testify to intimate interaction with the microbial mat.
The surface of the mat is scattered with Placozoa, which are reported from the fossil record for the first time. Xenacoelomorpha (Acoela)
and Platyhelminthes mainly occur at the termination of their burrows and are accompanied by rare Nematoda. Most of these soft-bodied invertebrates are Annelida, with representatives of different taxa of Polychaeta preserved within their burrows. The organisms and their traces are systematically described and interpreted, resulting in three new genera and species (Maculicorpus microbialis gen. et sp. nov., Gutticorpus concentrica gen. et sp. nov. and Palaeoscoloplos triassicus gen. et sp. nov.), two new ichnogenera and five new ichnospecies (Foveichnus lobatus igen. et isp. nov., F. canaliculatus igen. et isp. nov., Platyichnus lineatus igen. et isp. nov., Protovirgularia bifurcata isp. nov., and Kimberichnus digitatus isp. nov.). The preservation of this biota is closely related to the development of the
microbial mat and interaction with it, which favoured the in-situ entombment of organisms under the development of local dysoxia
and anoxia. Rapid burial (obrution), probably by storm deposition, contributed to their preservation. This Fossillagerstätte provides a
unique insight into the ecology of a Middle Triassic microbial mat on a mud flat before the onset of the Mesozoic Marine Revolution.
... As many helminths use vertebrate animal hosts or other hosts with a demonstrably better fossil record, it is helminth hosts that have been used to constrain helminth origins (by phylum) where a certain degree of host specificity might be assumed. With such approaches, some groups of nematodes and parasitic flatworms have been suggested as existing during the Cambrian-Ordovician (Littlewood 2006;Poinar 2011Poinar , 2015. In other cases, particularly where host-specificity is common, current biogeographic distribution patterns of host-parasite associations have been used to infer the temporal origin of the interaction (Borda et al. 2008;Verneau et al. 2009;Badets et al. 2011;Cuthill et al. 2016). ...
... Here we review the fossil record of helminths with the aim of providing suitable minimum and maximum constraints for dating their origins and key host transitions during their evolution. The fossil record of helminths is reviewed at greater length in other publications (Poinar 2011(Poinar , 2015Huntley and De Baets 2015;Parry et al. 2014Parry et al. , 2019b. We focus particularly on similarities and differences in the fossil record of helminths and in a phylogenetic context. ...
... The fossil record of various groups of helminths, or the phyla they belong to, was recently reviewed by various authors (Maas 2013;Poinar 2011Poinar , 2014Poinar , 2015Klompmaker and Boxshall 2015;Parry et al. 2014, Herlyn 2021. We discuss the bearing of these fossils and alternatives for constraining date estimates of the origins and diversification of parasitic helminths. ...
The fossil record of parasitic helminths is often stated to be severely limited. Many studies have therefore used host constraints to constrain molecular divergence time estimates of helminths. Here we review direct fossil evidence fossil evidence for several of these parasitic lineages belong to various phyla (Acanthocephala, Annelida, Arthropoda, Nematoda, Nematomorpha, Platyhelminthes). Our compilation shows that the fossil record of soft-bodied hel-minths is patchy, but more diverse than commonly assumed. The fossil record provides evidence that ectoparasitic helminths (e.g., pentastomids) have been around since the early Paleozoic, while endoparasitic helminths arose at least during, or possibly even before the late Paleozoic. Nematode lineages parasitizing terrestrial plant and animal hosts have been in existence at least since the Devonian and Triassic, respectively. All major phyla (Acanthocephala, Annelida, Platyhelminthes. Nematoda, Nematomorpha) had evolved endoparasitic lineages at least since the Mesozoic. Interestingly, although parasitism is considered derived within Metazoa, the oldest evidence for Nematoda and Platyhelminthes includes body fossils of parasitic representatives. Furthermore, the oldest fossil evidence of these parasitic lin-eages often falls within molecular divergence time based on host co-evolution suggesting the fossil record of helminths themselves might be just as good or at least complementary (and less circular in justification) to calibration based on host associations. Data also provide evidence for obvious host switches or extinctions,
