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Amber taphonomy. (A) Terrestrial, aquatic and underground insects are trapped by resin. (B) Resin may accumulate in the internal cracks and pockets within the wood, under and between the bark. (C) When resin is unconstrained it may form stalactites, drops and £ows, and may trap insects and other organisms. Under subaerial conditions resins lose volatiles. (D) Subter- ranean deposits of resins also form, produced by roots and by the aerial parts of the tree, and accumulate as large masses around the tree base. (E) In the majority of cases it is not known whether resin is transported to the deposit in which it becomes fossilised with the tree or separately. (F) Resins are introduced into water directly from the tree or following erosion of the soil. (G) Initial deposition of the resin, usually associated with organic rich sediments. (H) Diagenesis of the resin begins with burial. Nevertheless, some prediagenetic processes that a¡ect insects in resins are di⁄cult to distinguish from the e¡ects of diagenesis (see text). (I) Amber is usually reworked and deposits are time-averaged. 

Amber taphonomy. (A) Terrestrial, aquatic and underground insects are trapped by resin. (B) Resin may accumulate in the internal cracks and pockets within the wood, under and between the bark. (C) When resin is unconstrained it may form stalactites, drops and £ows, and may trap insects and other organisms. Under subaerial conditions resins lose volatiles. (D) Subter- ranean deposits of resins also form, produced by roots and by the aerial parts of the tree, and accumulate as large masses around the tree base. (E) In the majority of cases it is not known whether resin is transported to the deposit in which it becomes fossilised with the tree or separately. (F) Resins are introduced into water directly from the tree or following erosion of the soil. (G) Initial deposition of the resin, usually associated with organic rich sediments. (H) Diagenesis of the resin begins with burial. Nevertheless, some prediagenetic processes that a¡ect insects in resins are di⁄cult to distinguish from the e¡ects of diagenesis (see text). (I) Amber is usually reworked and deposits are time-averaged. 

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The major taphonomic processes that control insect preservation in carbonate rocks (limestones, travertines and nodules) are biological: insect size and wingspan, degree of decomposition, presence of microbial mats, predation and scavenging; environmental: water surface tension, water temperature, density and salinity, current activity; and diagene...

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... transport and deposition of resins are poorly understood (Fig. 6). Amber is rarely found within fossil wood, suggesting that they are nor- mally transported separately or that the amber is destroyed during diagenesis. Clastic sediments that yield amber are frequently rich in organic matter, but rarely in wood or bark ...
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... altered organic material. In¢lling occurs where the void left following decay is sub- sequently ¢lled by a mineral, as in pyrite in¢lled beetles from the Eocene London Clay of south- eastern England (Britton, 1960;Jarzembowski, 1992). The diagenetic minerals that most com- monly form casts are calcium carbonate, pyrolu- site and silica (Fig. 6A,B). In the Cretaceous of Las Hoyas and the Jurassic Solnhofen Limestone of Bavaria, calcite and pyrolusite precipitate in the spaces left following decay and form casts. Sometimes pyrolusite is con¢ned to the wing veins. In contrast, calcite in¢lls the void left when insects decay in the Eocene Bembridge Limestone and may replicate the ...
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... or months. Apatite forms more rapidly and yields higher ¢- delity of detail at the cellular level than any other mineral (Duncan and Briggs, 1996). Phosphatisa- tion is more prevalent in organisms such as ar- thropods, ¢shes and cephalopods (Wilby and Briggs, 1997) that have a relatively high reserve of organically bound phosphate in the carcass (Fig. 6D,E). This process frequently occurs in ma- rine environments, particularly in plattenkalks, as in the Upper Jurassic limestones of Solnhofen, Germany, and Cerin, France, the Upper Creta- ceous Hakel and Hjoula limestones of Lebanon, and Eocene limestones of Monte Bolca, Italy (Wilby and Briggs, 1997). However, such deposits do not always ...
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... In nodules. Insects are not often preserved in concretions. Examples include the famous Upper Carboniferous biotas of Mazon Creek, Illinois, USA, and Montceau-les-Mines, France, and the Middle Miocene biotas of the Barstow Formation of the Mojave Desert, California, USA, and of Izarra, A Ł lava, Spain (Figs. 6I and 7H). The Bar- stow Formation insects and other arthropods are preserved in three dimensions and are typically replaced by minerals, such as quartz (Fig. 7B), apatite, celestine, gypsum and zeolites, but in some cases the structure of the soft-tissues of these organisms is preserved (Palmer, 1957;Park, 1995;Park and Downing, 2001). The in- ...
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... tion begin as soon as the insect is trapped but before the resin is buried. It is not always clear which processes occur before and after burial of the resin so here we consider the diagenesis of insect inclusions to begin when they are ¢rst trapped, whereas diagenesis of the resin only be- gins when it is buried in a sedimentary deposit (Fig. 6). Resins have antiseptic and antibiotic properties that protect an insect carcass from de- cay, unlike those in limestones. The development of fungi around carcasses in amber where the hy- phae clearly are not oriented by the £ow of the resin indicates that the fungus grew after the in- sect was trapped; thus in some cases the resin ...
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... survive lithi¢cation of the sediment, only to be removed during diagenesis or weathering. The result may be an external mould. External moulds of insects commonly occur in limestones with a low organic matter content (Mart ¤nez-Delclo ' s et al., 1995), in travertines (Nel and Blot, 1990), and in carbonate nodules (Barro ¤ n et al., 2002). (4) In travertine . Travertines are freshwater carbonates that form in £uvial settings or springs with a high alkalinity. The major sources of carbonate in such settings are inorganically precipitated carbonate, carbonate precipitated as a result of photosynthesis, biogenic debris from calcare- ous plants and animals, and allochthonous material from carbonate rocks in the drainage basin (Dean and Fouch, 1991). Precipitation of CaCO 3 on the surface of organic remains results in their preservation as moulds. While plants are often preserved in such settings, insects are rare, exceptions being a dragon£y wing from the Holocene of Auriol, France ( Fig. 7G ; Papazian and Nel, 1989), and insects in the Miocene of Bo « ttingen, Germany (Zeuner, 1931). Traces of insect activity are even more rarely preserved in travertines, such as galls produced by the cecidomyid £y Harman- diola in leaves of Populus , from the Pleistocene of the Matarranya River in Teruel, Spain (Pen ‹ alver et al., 2002b), and the feeding in wood by a Quaternary beetle of the family Scolytidae, from Thu « ringens, Germany (Claus, 1958). (5) In nodules . Insects are not often preserved in concretions. Examples include the famous Upper Carboniferous biotas of Mazon Creek, Illinois, USA, and Montceau-les-Mines, France, and the Middle Miocene biotas of the Barstow Formation of the Mojave Desert, California, USA, and of Izarra, A Ł lava, Spain (Figs. 6I and 7H). The Barstow Formation insects and other arthropods are preserved in three dimensions and are typically replaced by minerals, such as quartz (Fig. 7B), apatite, celestine, gypsum and zeolites, but in some cases the structure of the soft-tissues of these organisms is preserved (Palmer, 1957; Park, 1995; Park and Downing, 2001). The insects of Montceau-les-Mines (France) and Izarra (Spain) are preserved as moulds (Caurel et al., 1994; Barro ¤ n et al., 2002). 3-D preservation indicates that nodules are formed by early diagenetic processes, prior to decay collapse. In these localities insects do not always occur in the centre of the nodules. Nodule formation begins with decay and release of CO 2 and NH 3 . This promotes an increase in concentration of the bicarbonate ion (HCO 3 3 ) promoting CaCO 3 precipitation around the carcass (Berner, 1968; Raiswell, 1987; Raiswell and Fisher, 2000). Calcareous nodules from the Montceau-les-Mines basin are dominated by siderite and pyrite with traces of phosphate; they may be traversed by calcite veins. This suggests an anoxic setting rich in organic matter, with a pH of 7 or lower (Caurel et al., 1994). The Miocene Barstow Formation concretions, on the other hand, were formed under dysaerobic, low energy conditions in a distal saline^alkaline lake (Park, 1995). No geochemical studies have been carried out in Izarra. Colour is rarely preserved in insect fossils because the majority of chemical compounds that cause it are lost rapidly after the death of the organism. The oldest preserved colour in insects is known from several Upper Carboniferous deposits associated with coals (Carpenter, 1992). Ex- amples of colour preserved on insects are known mainly from carbonate rocks (Fig. 8F) but also from amber (Fig. 8G). In some Mesozoic dragon£ies from carbonate rocks the wing venation pattern is only preserved where the wings were coloured; wing zones that lacked colour are not preserved. This suggests that the properties of the coloured wings in dragon£ies, perhaps the presence of melanin, may have promoted preservation. In other groups of insects that preserve colour, such as leafhoppers and scorpion£ies, the venation is preserved throughout. The metallic colours which are preserved in some beetles from the Eocene of Messel, Germany, for example, are not chemical in origin, but a product of multilayer re£ectors (Parker and McKenzie, 2003). Processes such as dehydration and carbonisation begin as soon as the insect is trapped but before the resin is buried. It is not always clear which processes occur before and after burial of the resin so here we consider the diagenesis of insect inclusions to begin when they are ¢rst trapped, whereas diagenesis of the resin only begins when it is buried in a sedimentary deposit (Fig. 6). Resins have antiseptic and antibiotic properties that protect an insect carcass from decay, unlike those in limestones. The development of fungi around carcasses in amber where the hy- phae clearly are not oriented by the £ow of the resin indicates that the fungus grew after the insect was trapped; thus in some cases the resin does not have fungicidal proprieties and may not harden quickly (Fig. 8A). Resin-encapsulated insects provide an opportunity to investigate diagenetic changes in organic matter that has been protected from external agents. Insect remains in copal and amber are usually restricted to the cuticle. After the insect is embedded in resin, anaerobic degradation occurs as a result of autolysis and the activity of endoge- nous bacteria (Allison and Briggs, 1991a,b). These processes may be inhibited by rapid dehydration, however, and labile tissues are sometimes preserved. Experiments have shown that early dehydration is critical to this process (Henwood, 1992a,b; Grimaldi et al., 1994). Henwood (1992b) argued that insects with well preserved internal organs represent individuals that dehydrated prior to complete entombment. Poinar and Hess (1982) suggested that such mummi¢ca- tion might be the result of an extreme case of inert dehydration. They considered that organic compounds such as sugars and terpenes in the resin might combine with water in the tissues to aid in the dehydration process. Grimaldi et al. (1994) argued that the role of terpenes is probably more signi¢cant than that of monosaccharides and other compounds, because terpenes occur in higher concentrations and would perfuse tissues more rapidly. During early diagenesis, £uids produced by decay and decomposition of labile tissues may react with sugars and terpenes in the resin, resulting in a white aureole around the carcass (Fig. 8B) that has been interpreted as a foam of microscopic bubbles (Mierzejewski, 1978; Weitschat and Wichard, 1998). This frequently occurs in insect larvae with a high proportion of labile tissues, but also in adults, particularly in Baltic and Dominican amber. Where foam is present on only one side of a carcass the other probably was exposed to the atmosphere long enough to become dehydrated before it was covered by a subsequent £ow. Grimaldi et al. (2000) reported New Jersey amber that is turbid due to foams. If soft part preservation is a function of dehydration, reduced evaporation underground might contribute to the lower preservation rate of subterranean organisms, but this is more likely a re£ection of their low mobility compared to £ying insects. Internal soft-tissues are preserved in both Dominican and Baltic amber (Grimaldi et al., 1994), but more commonly in the former, which sometimes yields cellular details, including mitochondria and nuclei (Poinar and Hess, 1982; Henwood, 1992a). Membranous structures, such as musculature, air sacs or tracheae, are generally better preserved than proteinaceous ones (Grimaldi et al., 1994). Internal soft-tissues also have been reported from Lebanese amber (Azar, pers. commun.). Gas exchange with the atmosphere may occur (Hopfenberg et al., 1988; Cerling, 1989), but this is unlikely to promote decay. Some macromolecules are more decay-resistant than others. DNA is highly susceptible to both hydrolysis and oxidation (Lindahl, 1993) and is rare in fossils more than 100 000 years old. Re- ports of DNA from insects in amber (Desalle et al., 1992; Cano et al., 1993) probably re£ect contamination (Austin et al., 1997; Walden and Robertson, 1997; Cooper and Poinar, 2000). Proteins are known to decay rapidly ; some of them, such as albumin, have similar characteristics to DNA (Poinar et al., 1996), while others, such as collagen, osteocalcin or keratin, are more resistant (but see Bada et al., 1999). Cellulose and chitin are carbohydrates that are easily biode- graded unless they are part of structural tissues through cross-linking with other molecules. Rec- ognisable traces of these biomolecules may last for millions of years (Briggs et al., 1998; Briggs, 1999). Low molecular weight fractions such as mono- and sesqui-terpenes readily di¡use from the resin into carcasses. Insect preservation in Baltic (gym- nospermous origin) and Dominican (angiosper- mous origin) ambers di¡ers (Grimaldi et al., 1994). Dominican amber usually preserves mem- brane structures, musculature, and nerve tissue, whereas preservation of these features is less fre- quent in Baltic amber where inclusions tend to be surrounded by a milky coating due to microbial decomposition, autolysis or reaction between decay £uids and compounds in the resin. Baltic amber contains a high concentration of resin acids, mainly succinic and communic. Dominican and Mexican ambers are similar to Baltic amber and fossil kauri, but di¡er in the stereochemistry of the methyl group and its side-chain. Thus they are not derived from communic acid but from ozic acid and its hydroxy derivative zanzibaric ...
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... and Wichard, 1998). The darker layers, usually thinner than the clear ones, are the result of rapid drying by sunlight and wind. These dark layers may contain insects that were not completely encapsulated until the arrival of the next £ow or drop of resin ( Fig. 3B). Some examples show that insect structures, such as wings, can prevent rapid drying of the resin (Fig. 5B). The majority of amber outcrops are allochthonous. Only in the Lower Cretaceous of Jordan is amber found in association with tree roots, possi- bly the producer plant (Nissenbaum and Horowitz, 1992). Amber may occur in association with coal seams, as in the Upper Cretaceous of Grassy Lake, Canada, or in the Lower Cretaceous of Wadi Zerka, north of Amman, Jordan (Poinar, 1992; Bandel et al., 1979). Some authors (Pike, 1993; Bandel et al., 1997) have interpreted such deposits as ‘in situ’, but they may represent transported accumulations. Where fragile structures such as stalactites or individual drops are preserved, it suggests that they have not been transported far, or that they have been carried by water without any contact with the bottom sediment. The presence of aquatic animals in amber indicates the proximity of water to the trees. Some species of Hymenaea in the Amazonian rainforest today may be periodically inundated (Langenheim, 1995), and likewise Agathis australis of New Zealand. The transport and deposition of resins are poorly understood (Fig. 6). Amber is rarely found within fossil wood, suggesting that they are normally transported separately or that the amber is destroyed during diagenesis. Clastic sediments that yield amber are frequently rich in organic matter, but rarely in wood or bark fragments. Where amber is preserved in wood, this may provide important evidence of the source plant and the part of the tree from which the amber origi- nated. Small pieces of amber occur in the wood of Metasequoia glyptostroboides from the Middle Eocene of Axel Heiberg Island, probably as a result of insect infestation (Labandeira, pers. commun.). Dejax in Azar (2000) suggested that Lebanese amber is produced by the cheirolepidacean Protopodocarpoxylon sp., congeneric with P. sub- rochii , from the Upper Jurassic of Morocco, and not by an araucariacean as previously thought. Ghiurca (1988) proposed a taxodiacean origin for Romanian Miocene amber. Knowlton (1896) proposed a cupressacean origin for some pieces of amber from the Upper Cretaceous of New Jersey, but Grimaldi et al. (2000) considered a pinacean or taxodiacean origin more likely based on chemical analysis of the amber. Although resins are produced by plants that would be expected to accumulate in deltaic and lacustrine sediments, remains of resins are rarely reported in studies of plant taphonomy in these environments. Gastaldo et al. (1987) reported no resin in their taphonomic study of plant remains in the Holocene crevasse splay in the Mobile Delta of Alabama, USA, nor in the backswamps of a Holocene oxbow lake of the Alabama River, where an important swamp cypress ( Taxodium ) community lived (Gastaldo et al., 1989). When resins occur in association with other plant remains in some sedimentary environments, they tend to be preserved as rare fragments. Resins are found as palynodebris in most delta-plain sub- environments associated with parenchyma tissues and wood debris, and sometimes in distributary channels, such as the Middle Miocene of the Niger Delta amid an angiosperm dominated forest (Oboh, 1992). Phytoclasts in the Recent Mahakan River Delta in Borneo (Gastaldo and Huc, 1992) include dipterocarpacean resins (dammar) as ei- ther duct in¢lls or amorphous to cylindrical clasts associated with other plant debris. These structures occurred in high energy depositional environments. Resin clasts may be up to several cen- timetres long and over 1 cm in diameter, and usually are rounded. These resins account for up to 4.5% of plant parts recovered on the delta front and in tidally in£uenced interdistributary areas (Gastaldo, 1994). The Lower Cretaceous amber of A Ł lava, Spain, occurs in sandy channels of the delta plain (Alonso et al., 2000). Insect carcasses that survive biostratinomic processes may be buried (Fig. 4). Subsequently they may be a¡ected by a number of processes: (1) early mineralisation ; (2) £attening; (3) deformation; (4) thermal maturation; and (5) reworking. Other factors, such as bioturbation, decomposition and weathering also may lead to biases in fossil insect assemblages. (1) Early mineralisation . The preservational state of fossil insects depends on the degree of decomposition when an insect arrives at the burial environment. Decay-resistant tissues may survive to be preserved as organic material ; diagenetic changes result in transformation to more stable molecules than those of the original (Briggs, 1999). Preservation of labile tissues requires replication by authigenic minerals before the loss of morphological detail. The type of mineral involved depends on the chemistry of the environment and the prevalent microbial processes (Efremov, 1950; Allison, 1988). Both types of preservation ^ of resistant and labile tissues ^ may occur at the same fossil locality and even within the same fossil (Pen ‹ alver et al., 1993). (2) Flattening . Flattening includes collapse of the carcass due to decomposition, and compaction as a result of overburden pressure. The degree and nature of £attening is determined by the grain size and composition of the sediment, the morphology and composition of the carcass, its orientation to the bedding, the nature and timing of diagenesis, and processes involved in cavity in¢ll. 3-D preservation of insects in limestone im- plies that mineralisation of the soft-tissues (Duncan and Briggs, 1996) and/or early cementation of the surrounding sediment (McCobb et al., 1998) was initiated prior to appreciable decay (Fig. 5C). The e¡ects of compaction may be di¡erentiated from tissue collapse through evidence of distor- tion of the mineral in¢ll, replacement, or coating (Allison and Briggs, 1991a). 3-D preservation is normal in amber. Subsequent compaction of the host sediment may result in ‘engraving’ of the surface and £attening of a piece of amber (Alonso et al., 2000; Zherikhin and Ross, 2000) but rarely a¡ects the inclusions. (3) Deformation . Fossil insects are sometimes distorted tectonically and this may lead to taxonomic misidenti¢cation (Pen ‹ alver, 1996) (Fig. 5D). Limestone is more resistant to weathering and erosion than amber, which may be very fragile due to intense polymerisation. (4) Thermal maturation . Maturation results in the transformation of the organic components of a fossil insect to a kerogen-like composition (Stankiewicz et al., 2000). It causes amber to become darker and more fragile by promoting the loss of volatile terpenes and increasing the rate of polymerisation. It may also increase amber plas- ticity. (5) Reworking . Amber with insect inclusions is often reworked. Fossil insects in carbonates are only likely to be reworked if they are preserved in nodules. Rapid burial favours exceptional preservation (Seilacher et al., 1985) by eliminating scavengers and promoting anaerobic conditions that inhibit bioturbators. It results in the preservation of articulated carcasses (Fig. 5E). Low rates of decay are necessary to allow authigenic minerals to form quickly enough to preserve the most labile soft- tissues (Briggs, 1995b). If decay outpaces mineralisation, only the most decay-resistant tissues and structures will be preserved. Organic remains survive only where chemical (hydrolysis, oxidation) and biological (enzymatic and microbial activity) degradation is prevented (Briggs, ...

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... To date, there is no record of calcified or silicified insects embedded in amber and both preservational types are rare in the fossil record of insects (Lindgren et al., 2019;Martıńez-Delclòs et al., 2004;McCobb et al., 1998;Muscente et al., 2017;Park & Downing, 2001). Here, we provide the first definitive record of calcified and silicified insects embedded in fossil resin. ...
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Fossilized tree resin, or amber, commonly contains fossils of animals, plants and microorganisms. These inclusions have generally been interpreted as hollow moulds or mummified remains coated or filled with carbonaceous material. Here, we provide the first report of calcified and silicified insects in amber from the mid-Cretaceous Kachin (Burmese) amber. Data from light microscopy, scanning electron microscopy (SEM), energy-dispersive and wavelength-dispersive X-ray spectroscopy (EDX and WDX), X-ray micro-computed tomography (Micro-CT) and Raman spectroscopy show that these Kachin fossils owe their preservation to multiple diagenetic mineralization processes. The labile tissues (e.g. eyes, wings and trachea) mainly consist of calcite, chalcedony and quartz with minor amounts of carbonaceous material, pyrite, iron oxide and phyllosilicate minerals. Calcite, quartz and chalcedony also occur in cracks as void-filling cements, indicating that the minerals formed from chemical species that entered the fossil inclusions through cracks in the resin. The results demonstrate that resin and amber are not always closed systems. Fluids (e.g. sediment pore water, diagenetic fluid and ground water) at different burial stages have chances to interact with amber throughout its geological history and affect the preservational quality and morphological fidelity of its fossil inclusions.
... Fossil insects are usually preserved as adpressions or inclusions without lighter pigment colour [42]; structural colour is also infrequently discovered in fossil insects owing to the incomplete preservation of ultrastructure [43][44][45][46]. Though three-dimensional insects are preserved in amber, colour has been rarely recorded [47][48][49][50]. ...
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Aposematic coloration is among the most diverse antipredator strategies, which can signal unpleasantness of organisms to potential predators and reduce the probability of predation. Unlike mimesis, aposematic coloration allows organisms to warn their predators away by conspicuous and recognizable colour patterns. However, aposematism has been a regular puzzle, especially as the long-term history of such traits is obscured by an insufficient fossil record. Here, we report the discovery of aposematic coloration in an orthopteran nymph from Mid-Cretaceous Kachin amber (99 million years old). It is attributed to the extinct family Elcanidae and erected as a new genus identified by conspicuous dark/light-striped coloration, four apical spurs on the metatibia, a two-segmented metatarsus and unsegmented stylus. It represents the first fossil orthopteran preserved with aposematic coloration from the Mesozoic, demonstrating that orthopterans had evolved aposematism by the Mid-Cretaceous. Our findings provide novel insights into the early evolution of anti-predator strategies among orthopterans. Together with mimesis, debris-carrying camouflage and aposematism previously reported, our findings demonstrate the relative complexity of prey–predator interactions in the Mesozoic, especially in the Mid-Cretaceous Kachin amber forest. This article is part of the theme issue ‘The impact of Chinese palaeontology on evolutionary research’.
... These Jurassic specimens may have been predatory rather than parasitic organisms. Such limestones are also important sources of insects (Martıńez-Delclòs et al. 2004). Although it can be difficult to distinguish parasite and scavenger remains in some lithographic limestone material (Wilson et al. 2011), the Jurassic Nusplingen Limestone has yielded isopods attached to squids possibly representing their hosts (Polz et al. 2006;Haug et al. 2021). ...
... The amber record extends back to the Carboniferous (Bray and Anderson 2009), but the oldest globally distributed amber with inclusions has been reported from the Triassic (Seyfullah et al. 2018). Massive amber deposits rich in inclusions are largely concentrated in the Cretaceous and Cenozoic (Martıńez-Delclòs et al. 2004)-only these so far have yielded a diverse spectrum of parasitic remains (Poinar 2011b(Poinar , 2014. Due to where it forms, fossiliferous amber predominantly includes terrestrial, rather than fully marine, organisms (Solórzano Kraemer et al. 2018). ...
... This lack can be illustrated for nematodes where Maastrichtian-Paleogene or pre-Cretaceous amber data are missing ( Fig. 1.3), which makes it hard to evaluate the impact of the end-Cretaceous mass extinction or Paleogene-Eocene Thermal Maximum (PETM). In some cases, meaningful studies can, however, be done on the stage level by combining amber deposits with data from other Lagerstätten (e.g., insects: Martıńez-Delclòs et al. 2004). Labandeira and Li (2021) used such an approach to efficiently quantify the Mid-Mesozoic Parasitoid Revolution in insects at the family level. ...
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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.
... Amber records are relatively frequent in Cenozoic deposits and have occurred in terrestrial sediments throughout the geologic record since the Carboniferous (van Bergen et al., 1995), becoming abundant from Early Cretaceous with the rise of the coniferous Araucariaceae, particularly in tropical and subtropical forests (Martinez-Delcl os et al., 2004). Despite its rareness, it is crucial to understand evolutionary processes in trapped animal and plant taxa since its exceptional preservation setting may lead to soft tissue presence (see, Anderson, 2001;Poinar ands Mastalerz, 2000). ...
Article
Fossil resins and ostracods are well-known in Brazilian Cretaceous sedimentary Basins, especially in the Araripe Basin. The present work reports several ostracods encapsulated in an amber sample recovered from limestones of the Crato Formation (Araripe Basin, Northeastern Brazil). The amber was analyzed under optical microscopy revealing several ostracod specimens. Considering the general morphology, the recovered specimens were attributed to the freshwater to brackish genera Pattersoncypris Bate, 1972 and Damonella Anderson, 1966 in the superfamily Cypridoidea. Additionally, palynological analyses of the limestone rock around the amber demonstrate the predominance of pollen grains of the Classopolis genus, produced by conifers of Cheirolepidiaceae family, suggesting this family as possible botanical source of the fossil resin. The proposed interpretation for this preservation is as follow: (i) the lake level variations transported the ostracods to the margin; (ii) drops of resin exuded from the trunk fell to the margin on the dead ostracods; (iii) the exposed resin underwent polymerization preserving the ostracods; (iv) and finally, the amber was preserved in the laminated calcareous deposit. The record described here provides a detailed study of organisms fossilized in Brazilian amber as well as it reports the oldest record of ostracods enclosed in fossil resins (Aptian age).
... Perforated basiconic (p-bas) sensilla are short transparent hairs with rounded tips (Fig. 3b). We considered that the degree of darkness in sensillum appearance reflects the thickness of cuticular walls because insect fossils in amber well preserve the exoskeletal structure (Martínez-Delclòs et al. 2004;Labandeira 2014). Putative grooved basiconic (g-bas) sensilla (thick, double-walled in P. americana) were therefore designated for dark serrate structures, which are short and stand on the antenna surface (Figs. ...
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Animals highly depend on their sensory organs to detect information about their surrounding environment. Among animal sensory organs, those of insects have a notable ability to detect information despite their small size, which might be, therefore, one of the reasons for the evolutionary success of insects. However, insect sensory organs are seldom fossilized in sediments due to their small size and fragility. A potential solution for this problem is the study of exceptionally well-preserved fossil material from amber. Unfortunately, the resolution of existing non-destructive analysis is insufficient to observe details of these micro sensory organs even with amber preservation. Here, we focus on the analysis of the micro sensory organs of an extinct male cockroach (Huablattula hui Qiu et al., 2019) in Cretaceous amber by combining destructive and non-destructive methods. Compared to extant species inhabiting dark environments, H. hui has relatively large compound eyes, and all the antennal sensilla for detecting multimodal information observed here are fewer or smaller. The characteristics of these sensory organs support the diurnality of the bright habitats of H. hui in contrast to many extant cockroaches. Like extant male mantises, grooved basiconic type sensilla exist abundantly on the antenna of the fossilized specimen. The abundance of grooved basiconic sensilla in mantid males results from using sex pheromones, and therefore, H. hui may have likewise used mantis-like intersexual communication. These lines of evidence suggest that the ecology and behavior of Cretaceous cockroaches were more diverse than those of related extant species.