Organismes filamenteux de l’ambre du Santonien de Belcodène (Bouches-du-Rhône,France)

Millimetric amber grains associated with lignite debris were recently reported in the Santonian marine series from Belcodène (Bouches-du-Rhône, France). These are mainly yellow to reddish drop-shaped grains, more or less transparent. They reveal the presence of various microorganisms, belonging to prokaryotes (bacteria, actinomycetes) and eukaryotes (filamentous fungi) here described for the first time. These microorganisms form sometimes crusts around the amber grains and grew centripetally into the ancient resin before its solidification. The depositional environment of amber was open to marine influences, while the original environment of resin flow was a coastal forest with dominant angiosperms.     

Spider web in Late Cretaceous French amber (Vendée): The contribution of 3D image microscopy

Late Cretaceous amber from La Garnache (France, Vendée) contains filamentous networks that have all the characteristics of spider webs. Using methods of classic and confocal microscopy, the web architecture and the thread structure are described. The geometry of the webs preserved in amber is presented in 3D imaging. Unlike most of the spider webs identified in amber, there are no regular radiating webs growing in two dimensions characteristic of the well-known orb web. A number of the characters would correspond to the apparently irregular organization of cob-type web or sheet web. By using confocal microscopy, we can highlight the preserved autofluorescence of spider silk proteins and new characters are proposed to identify the spider webs or fragments of webs in amber.     

Putative ancient microorganisms from amber nuggets.

Evolutionary microbiology studies based on the isolation of ancient DNA and/or microbial samples are scarce due to the difficulty of finding well preserved biological specimens. However, amber is a fossil resin with natural preserving properties for microbial cells and DNA. The visualization by transmission electron microscopy of different microorganism-like specimens found in amber nuggets from both the Miocene and the Cretaceous periods was accompanied by studies of ancient DNA obtained from the nuggets. After the design of specific primers based on the present sequences of both genes in Saccharomyces cerevisiae, the ancestral AGP2 sequence from the Miocene, as well as the 18S rRNA from the Cretaceous, were amplified.     

The Range of Bioinclusions and Pseudoinclusions Preserved in a New Turonian (~90 Ma) Amber Occurrence from Southern Australia

A new Turonian amber occurrence, representing the oldest in situ amber locality in Australia and the southern-most locality in Gondwana, has recently been discovered in the Otway Basin of Victoria. The amber was collected from petroleum cores and many pieces contain a range of inclusions that can provide information on the depositional history of the resin. To date, one species of fern spore (Cyathidites minor) and one species of lycophyte spore (Kraeuselisporites sp?) have been conclusively identified in the amber, along with filamentous microorganisms and degraded plant matter. Several samples are also rife with pseudoinclusions as reported recently in other ambers. The abundance of preserved particulate debris and wind dispersed spores suggest that the Otway amber formed subaerially. Furthermore, based on the range of bioinclusions and forms of pseudoinclusions preserved within a single piece of amber, the locus of hardening for individual samples is variably interpreted as occurring in the tree tops, on the tree trunk or on the ground surface. Notably, specific inclusion assemblages are associated with certain colours of amber. By extension, and in accordance with recent studies, amber colour may be indicative of depositional environment. Variation in the environment of solidification may, therefore, be sufficient to account for the broad range of morphological characteristics preserved in a single amber deposit.     

L’ambre campanien du Mas d’Azil (Ariège,France) : gisement,micro-inclusions,taphonomie

The amber of Le Mas d’Azil (Ariège, France), fashioned by the Magdalenian people of Le Mas d’Azil cave, was collected in clay levels rich in Cupressinoxylon Göppert, of the Campanian Labarre Sandstone Formation, which is a large deltaic set, infilling the sub-Pyreneean trough. The amber pieces are small and resemble modern resin exudates on coniferous trunks. We describe following micro-inclusions. Actinomycetes: Cardonia stellata, nov. gen., nov. sp., located close to the surface of amber pieces, is abundant and displays chains of conidia and isolated aleuriospore. Nocardiopsis ? sp. D is rare. Actinomycete “de type Salignac” is abundant. Its filaments often display a tendril shape, which seems to prelude to a mycelium fragmentation. Other bacteria: Leptotrichites resinatus Schmidt ( Schmidt and Schäfer, 2005), poorly represented, is more variable than the already known material; cf. Sphaerotilus sp., very abundant, also displays differences with the Cenomanian “Sphaerotilus sp.”. Eukaryotes: one fungal filament, and a group of spores, pollens or cysts. Inorganic inclusions: gas bubbles, pseudo-protists of B and C? types, and tiny, transparent, cubic crystals. It seems that most of the quoted prokaryotes were resinicolous organisms, able to settle on the surface of the exudate, and grow in the resin, after inoculation either by a contact with the substrate, or by an anemophilic dispersion of spores. This “taphonomic way” seems here to be more general than trapping.     

Insect outbreaks produce distinctive carbon isotope signatures in defensive resins and fossiliferous ambers

Despite centuries of research addressing amber and its various inclusions, relatively little is known about the specific events having stimulated the production of geologically relevant volumes of plant resin, ultimately yielding amber deposits. Although numerous hypotheses have invoked the role of insects, to date these have proven difficult to test. Here, we use the current mountain pine beetle outbreak in western Canada as an analogy for the effects of infestation on the stable isotopic composition of carbon in resins. We show that infestation results in a rapid (approx. 1 year) (13)C enrichment of fresh lodgepole pine resins, in a pattern directly comparable with that observed in resins collected from uninfested trees subjected to water stress. Furthermore, resin isotopic values are shown to track both the progression of infestation and instances of recovery. These findings can be extended to fossil resins, including Miocene amber from the Dominican Republic and Late Cretaceous New Jersey amber, revealing similar carbon-isotopic patterns between visually clean ambers and those associated with the attack of wood-boring insects. Plant exudate δ(13)C values constitute a sensitive monitor of ecological stress in both modern and ancient forest ecosystems, and provide considerable insight concerning the genesis of amber in the geological record.     

Protist-like inclusions in amber, as evidenced by Charentes amber

The mid-Cretaceous amber of France contains thousands of protist-like inclusions similar in shape to some ciliates, flagellates and amoebae. The sheer abundance of these inclusions and their size variation within a single amber piece are not concordant with true fossil protists. French amber is coniferous in origin, which generally does not preserve well protists without cell walls. Thus, it would be surprising if French Cretaceous amber had preserved millions of protists. Here, we present a survey of the protist-like inclusions from French amber and attempt to elucidate their origins.Diverse Cretaceous ambers (from Spain, Germany and Lebanon), also derived from conifer resins, contain thousands of protist-like inclusions. In contrast, Tertiary ambers and modern resins are poor in protist-like fossils. This suggests these inclusions originated from early Cretaceous plant resins, probably secreted with the resin by trees that did not survive after the Cretaceous (such as the Cheirolepidiaceae). A review of the recent literature on amber microfossils indicates several protist-like inclusions that are unlikely to have a biological origin have already been described as real fossil protists. This is problematic in that it will bias our understanding of protist evolution.     

Mid-Cretaceous Burmese amber pelecinid wasps (Hymenoptera,Pelecinidae) support the hypothesis of an Asian origin of the family

A new species of pelecinid wasp, Eopelecinus marechali sp. nov., is described and figured from mid-Cretaceous Burmese amber based on a single well-preserved female specimen. Contrary to Eopelecinus inopinatus Jouault et al., 2020a, unique other Eopelecinus known from this deposit, the new species is based on a complete female specimen. This discovery confirms that the Pelecinidae were highly diverse during the Cretaceous and highlights the underestimated diversity of the genus Eopelecinus in Burmese amber biota. Eopelecinus marechali sp. nov. differs from all other Eopelecinus species by its unique metasomal ratio. A summary on the fossil pelecinid species with distributions and ages is provided. Based on the particular geological history of the West Burmese Terrane and the fossil record of the family, the hypothesis of an Asian origin of the family is discussed. The records of Eopelecinus in both Laurasia and Burmese amber biota, during the mid-Cretaceous, suggest that possible transfers of fauna have taken place between these two geological blocks.     

New bethylid and chrysidid wasps (Hymenoptera: Chrysidoidea) from Canadian Late Cretaceous amber

A new bethylid species, Celonophamia granama, and two new chrysidid species, Procleptes eoliami, and P. hopejohnsonae, are described from Late Cretaceous (Campanian) amber collected at the Grassy Lake locality in Alberta, Canada. Within the deposit these taxa constitute the first bethylid, and the second and third chrysidid species to be described, respectively. The new taxa expand the sparse fossil record of Chrysidoidea, particularly that of Chrysididae—a group that was previously represented by only three described species in the Mesozoic. The presence of Celonophamia species in both Canadian amber and Siberian (Taimyr) amber further emphasizes faunal similarities between these two northern Late Cretaceous amber deposits. Given the prevalence of metallic coloration in Chrysididae, the specimens described here also provide evidence for the taphonomic alteration of perceived insect colors in Cretaceous amber inclusions.     

The first cupedine beetle from Burmese amber (Coleoptera: Cupedidae)

A rare archaic beetle, Mallecupes qingqingae gen. et sp. n., (Insecta: Coleoptera: Archostemata: Cupedidae) is described from mid-Cretaceous Burmese amber. It shows affinity with Paracupes found in South America today and ‘Paracupes’ found in North America during the Cretaceous. Archostemata are diverse in Burmese amber.     

A new ripiphorid beetle from Upper Cretaceous Burmese amber sheds light on early evolution of the extant subfamily Ripidiinae (Coleoptera: Ripiphoridae)

Fossils belonging to Ripidiinae are rare. Here, we describe and figure a remarkable new genus and species of Ripidiinae, Protoripidius burmiticus gen. et sp. nov., from the Upper Cretaceous amber of Myanmar. Protoripidius can be placed in the extant subfamily Ripidiinae based on the widely separated and abbreviated elytra (in male), unfolded hind wings, simple claws and the absence of tibial spurs. Protoripidius bears many transitional features shedding new light on the relationships of the two extant tribes of Ripidiinae. The discovery also highlights the palaeodiversity of the subfamily Ripidiinae in the mid-Cretaceous.     

Termite coprolites (Insecta: Isoptera) from the Cretaceous of western France: A palaeoecological insight

This paper presents fossil faecal pellets - also named coprolites or frass - attributed to termites, which were found in amber and lignitic clay from the Wealden (Hauterivian-Barremian?), Late Albian and Early Cenomanian of south-western France. These coprolites have a characteristic subcylindrical shape and hexagonal transverse section and are assignable to Microcarpolithes hexagonalis Vangerow. The termite families that possibly produced these coprolites are discussed. The noticeable lack of termite attacks on the fossil wood associated with amber and lignitic clay is taphonomically analyzed in relation with the palaeoflora and palaeoclimate of these amber forests. The different medium where coprolites were found (amber, wood, sediments) suggests that primitive Cretaceous termites had already developed various biologies, such as wood or cryptic foraging, but probably not yet soil-feeding.     

缅甸北部克钦琥珀中的蜻蜓目化石

近五年,缅甸北部白垩纪中期克钦琥珀中相继发现了数百枚蜻蜓目化石,包含现生蜻蜓目三个亚目类群,目前已发表16科29属35种,在所有已知琥珀记录中数量和多样性最高。克钦琥珀中的蜻蜓目以均翅亚目(豆娘)为主,以Burmahemiphlebia zhangi最为常见,不少现生豆娘的化石记录也首次在克钦琥珀中发现,包括Perilestidae,Platycnemididae和Platystictidae等。此外,克钦琥珀中发现了一些中生代沉积岩中常见的蜻蜓目类群,如Araripegomphidae, Gomphaeschnidae和Stenophlebiidae等,指示克钦琥珀的时代可能为早白垩世晚期。这些发现为探讨蜻蜓目部分类群的起源、演化和揭示生物古地理提供了有力证据。     

A new scorpion fossil from the Cretaceous amber of Myanmar (Burma). New phylogenetic implications

A fossil scorpion belonging to a new family, genus and species, Chaerilobuthus complexus gen. n., sp. n., is described from Cretaceous amber of Myanmar (Burma). This is the third species and the fourth scorpion specimen to have been found and described from Burmese amber. The new family seems quite distinct from the family Archaeobuthidae Lourenço, 2001 described from Cretaceous amber of Lebanon.     

Palaeoanellus dimorphus gen. et sp. nov. (Deuteromycotina): a Cretaceous predatory fungus

In habitats where nitrogen is the limiting factor, carnivorous fungi gain an advantage by preying on nematodes and other microorganisms. These fungi are abundant in modern terrestrial ecosystems, but they are not predestined for preservation as fossils. Conclusions on their evolutionary history are therefore mainly based on molecular studies that are generally limited to those taxa that have survived until today. Here we present a fossil dimorphic fungus that was found in Late Albian amber from southwestern France. This fungus possessed unicellular hyphal rings as trapping devices and formed blastospores from which a yeast stage developed. The fossil probably represents an anamorph of an ascomycete and is described as Palaeoanellus dimorphus gen. et sp. nov. Because predatory fungi with regular yeast stages are not known from modern ecosystems, the fungus is assumed to not be related to any Recent carnivorous fungus and to belong to an extinct lineage of carnivorous fungi. The inclusions represent the only record of fossil fungi that developed trapping devices, so far. The fungus lived c. 100 million years ago in a limnetic-terrestrial microhabitat, and it was a part of a highly diverse biocenosis at the forest floor of a Cretaceous coastal amber forest.     

First fossil horsefly (Diptera: Tabanidae) in Miocene Mexican amber

The fossil record of the Tabanidae is sparse when compared with other families of Diptera. Even in amber they are rare, probably because of their size and specific flight behavior. Horseflies from amber are only known from Cretaceous age New Jersey amber as well as from the Tertiary age Baltic and Dominican amber, but are herein described for the first time, with Stenotabanus oleariorum sp. n., from Mexican amber. The new species is compared to the fossil horseflies of the same genus S. brodzinskyi Lane, Poinar and Fairchild 1988 and S. woodruffi Lane and Fairchild 1989 from Dominican amber.     

A remarkable new fossil species of Amplectister with peculiar hindleg modifications (Coleoptera: Histeridae): further evidence for myrmecophily in Cretaceous clown beetles

Myrmecophily is a phenomenon of the symbiosis of organisms that depend on various ant (Formicidae) societies. Such interspecies associations are found in several unrelated lineages within the clown beetle family Histeridae. Recent studies have suggested that the origin of myrmecophily can be traced back to mid-Cretaceous based on a few fossil records from Kachin amber from northern Myanmar. Here, we describe a remarkable new species, Amplectister terapoides n. sp., from Kachin amber. This is the second species of the extinct genus Amplectister Caterino and Maddison, which has been found from the same amber deposit and has also been considered to be myrmecophilous. The new species here described has the most heavily modified hindlegs in any fossil histerids or even beetles discovered until now, indicating further evidence for ant colony association. Our discovery demonstrates that significant and diverse morphological adaptations to myrmecophily had already occurred during the Cretaceous.     

Double fossilization in eukaryotic microorganisms from Lower Cretaceous amber

Background  

Microfossils are not only useful for elucidating biological macro- and microevolution but also the biogeochemical history of our planet. Pyritization is the most important and extensive mode of preservation of animals and especially of plants. Entrapping in amber, a fossilized resin, is considered an alternative mode of biological preservation. For the first time, the internal organization of 114-million-year-old microfossils entrapped in Lower Cretaceous amber is described and analyzed, using adapted scanning electron microscopy in backscattered electron mode in association with energy dispersive X-ray spectroscopy microanalysis. Double fossilization of several protists included in diverse taxonomical groups and some vegetal debris is described and analyzed.