Xavier Delclòs

University of Barcelona | UB · Dept. of Earth and Ocean Dynamics

When a vertebrate carcass begins its decay in terrestrial environments, a succession of different necrophagous arthropod species, mainly insects, are attracted. Trophic aspects of the Mesozoic environments are of great comparative interest, to understand similarities and differences with extant counterparts. Here, we comprehensively study several e...

Flint was the most widely used lithic raw material in Europe in Prehistory and, more specifically, was a fundamental resource in the economic and social networks of hunter-gatherer groups in the Cantabrian Spain during the Upper Palaeolithic. The undeniable preference for it compared with other resources was due to a series of factors, such as its...

We report a fossil geometrid moth, a male, virtually complete, preserved in a clear piece of Miocene Dominican amber dating from 19 to 16 Mya. Fore- and hindwings appear partially overlapped, and all body characters are visible externally in dorsal and ventral views, including the outer surface of the valvae of the genitalia. The scale pattern on t...

Braconid parasitoid wasps are a widely diversified group today, while their fossil record from the Mesozoic is currently poorly known. Here, we describe Utrillabracon electropteron Álvarez-Parra & Engel, gen. et sp. nov. , from the upper Albian (Lower Cretaceous) amber of San Just in the eastern Iberian Peninsula. The holotype specimen is incomplet...

La Pedrera de Meià (LPM) fossil site, discovered in the 19 th century, is an important Barremian Konservat-Lagerstätte located at the southern slope of the Montsec range (Lleida province, Spain). LPM is comparable in fossil preservation with other European lithographic limestones lagerstätten sites such as Solnhofen (Germany), Cerin (France) or Las...

The Cretaceous family Spathiopterygidae (Hymenoptera: Diaprioidea), containing five species in four genera, showed a wide distribution from the upper Barremian to the Turonian. We describe two new representatives of the family from the upper Albian San Just outcrop in the eastern Iberian Peninsula that correspond to Diameneura marveni gen. et sp. n...

Barklice are insects belonging to the order Psocodea. They are herbivorous or detritivorous, and inhabit a wide range of environments. Their oldest fossil record dates back to the late Carboniferous, but it was not until the Cretaceous that they became much more diverse. However, their fossil record could be affected by taphonomic processes due to...

Although specimens in fossil to Recent resins are remarkable for their fidelity of preservation, amber is well known and studied, unlike the younger resins as Pleistocene copal (2.58–0.0117 Ma) and Holocene copal (0.0117 Ma–1760 AD), or Defaunation resin, which is resin produced after 1760 AD. However, the scientific relevance of these younger resi...

Interactions between the two most abundant groups of organisms on Earth, insects and plants, are especially relevant in evolutionary studies. We review different aspects related to endophytic eggs laid by insects in plants for more than 300 Myrs, from the Carboniferous to the Miocene. This work provides a meta-analysis of endophytic insect oviposit...

We report a fossil geometrid moth, a male, virtually complete, preserved in a clear piece of Miocene Dominican amber dating from 19–16 Mya. Fore- and hindwings appear partially overlapped, and all body characters are visible externally in dorsal and ventral views, including the outer surface of the valvae of the genitalia. The scale pattern on the...

The study of extinct Cretaceous families of Hymenoptera is crucial as it provides unique glimpses into the diversification of the group during a dramatic period in evolutionary history. The †Serphitidae were a family of parasitoid wasps, with representatives distributed worldwide during the Cretaceous, ranging temporally from the Albian through the...

Acercaria is a group of insects comprising the extant orders Psocodea, Thysanoptera, and Hemiptera. The extinct orders †Lophioneurida (late Carboniferous–Late Cretaceous), †Permopsocida (early Permian–Late Cretaceous), †Miomoptera, and †Hypoperlida (both late Carboniferous-late Permian) are also included within Acercaria. †Lophioneurida is grouped...

Spiders are renowned hunters that often efficiently capture prey using a web, the early evolution of which remains obscure as it rarely fossilizes. We report several Cretaceous spider web portions, not single silk strands, preserved in 110- and 105-million-year-old amber (Albian) from five Spanish localities. A partial spider web without prey from...

Dinosaur bonebeds with amber content, yet scarce, offer a superior wealth and quality of data on ancient terrestrial ecosystems. However, the preserved palaeodiversity and/or taphonomic characteristics of these exceptional localities had hitherto limited their palaeobiological potential. Here, we describe the amber from the Lower Cretaceous dinosau...

Specimens in fossil to Recent resins are remarkable for their fidelity of preservation. Amber is well known and studied, contrary to younger resins as Pleistocene copal (2.58-0.0117 Ma) and Holocene copal (0.0117 Ma—1760 AD), or Defaunation resin, which is resin produced after 1760 AD. The scientific relevance of these younger resins preserving art...

Dinosaur bonebeds with amber content, yet scarce, offer a superior wealth and quality of data on ancient terrestrial ecosystems. However, the preserved palaeodiversity and/or taphonomic characteristics of these exceptional localities had hitherto limited their palaeobiological potential. Here we describe the amber from the Lower Cretaceous dinosaur...

Terrestrial isopods (Crustacea: Oniscidea) are a model group for studying the colonization of land. However, their fossil record is remarkably scarce and restricted to amber inclusions, and therefore amber deposits represent valuable windows to their past diversity and morphology. Here we present a new collection of 11 terrestrial isopod specimens...

Chemical analysis of amber, copal, and resin is a valuable tool for interpreting the botanic origin of amber and the ecological role of resin in ancient forests. Here we investigated for the first time the volatile and semi-volatile composition of Cretaceous amber, as well as copal and Defaunation resin produced by trees of the family Araucariaceae...

Insect-fungus mutualism is one of the better-studied symbiotic interactions in nature. Ambrosia fungi are an ecological assemblage of unrelated fungi that are cultivated by ambrosia beetles in their galleries as obligate food for larvae. Despite recently increased research interest, it remains unclear which ecological factors facilitated the origin...

The early fossilization steps of natural resins and associated terminology are a subject of constant debate. Copal and resin are archives of palaeontological and historical information, and their study is critical to the discovery of new and/or recently extinct species and to trace changes in forests during the Holocene. For such studies, a clear,...

Fossil records of vertebrate integuments are relatively common in both rocks, as compressions, and amber, as inclusions. The integument remains, mainly the Mesozoic ones, are of great interest due to the panoply of palaeobiological information they can provide. We describe two Spanish Cretaceous amber pieces that are of taphonomic importance, one b...

The monospecific family Mysteriomorphidae was recently described based on two fossil specimens from the Late Cretaceous Kachin amber of northern Myanmar. The family was placed in Elateriformia incertae sedis without a clear list of characters that define it either in Elateroidea or in Byrrhoidea. We report here four additional adult specimens of th...

Past claims have been made for fossil DNA recovery from various organisms (bacteria, plants, insects and mammals, including humans) dating back in time from thousands to several million years BP. However, many of these recoveries, especially those described from million-year-old amber (fossil resin), have faced criticism as being the result of mode...

We describe Psyllipsocus yoshizawai sp. nov., the oldest and first Cretaceous species of the extant genus Psyllipsocus (Psocodea: Trogiomorpha: Psyllipsocidae). This is the fifth genus and sixth species to be identified within the family Psyllipsocidae from the Cretaceous and the third genus and fourth species of psyllipsocids from the Cenomanian a...

Recently, the Society of Vertebrate Paleontology (SVP) has sent around a letter, dated 21st April, 2020 to more than 300 palaeontological journals, signed by the President, Vice President and a former President of the society (Rayfield et al. 2020). The signatories of this letter request significant changes to the common practices in palaeontology....

Two virtually complete termites in Lower Cretaceous amber from the Peñacerrada I outcrop, Spain, are described and figured, representing the most well-preserved Isoptera yet discovered from the Albian stage. The material is described as Ithytermes montoyai gen. et sp. nov., and is similar in many details to the slightly younger Krishnatermes yoddha...

The loss of biodiversity during the Anthropocene is a constant topic of discussion, especially in the top biodiversity hotspots, such as Madagascar. In this regard, the study of preserved organisms through time, like those included in "Madagascar copal", is of relevance. “Madagascar copal" originated from the leguminous tree Hymenaea verrucosa, whi...

Psocodea is an insect order including the parasitic lice (Phthiraptera) and the psocids (‘Psocoptera’), counting more than 10,000 living species known to date. The oldest representative dates from the Moscovian (Carboniferous), but their diversification occurs during the Cretaceous, the amber being the main source of this knowledge. Up to now, four...

The Cretaceous fossil record of amber provides a variety of evidence that is essential for greater understanding of early pollination strategies. Here, we describe four pieces of ca. 99-million-year-old (early Cenomanian) Myanmar amber from Kachin containing four closely related genera of short-winged flower beetles (Coleoptera: Kateretidae) associ...

Three larval neuropterans (Insecta: Neuropterida) with straight mandibulomaxillary stylets are described from Lower Cretaceous (late Albian, ~105 Ma) Spanish amber: a third-instar beaded lacewing (Berothidae) from the Peñacerrada I locality (Burgos, Spain), and two specimens from the San Just locality (Teruel, Spain), i.e., a tentative first-instar...

A new fossil genus of the family Hybotidae is described, based on male and female specimens. The new genus is monotypic: Syneproctus caridadi gen. et sp. nov. It belongs to the subfamily Hybotinae and shares some characters with the extant genera Syneches Walker, 1852, Stenoproctus Loew, 1858 and Chillcottomyia Saigusa, 1986; however, the differenc...

A new Cretaceous dustywing, Soplaoconis ortegablancoi gen. et sp. nov. (Neuroptera: Coniopterygidae), is described from four specimens preserved in Early Cretaceous (Albian, ~105Ma) El Soplao amber (Cantabria, northern Spain). Two additional specimens are assigned to this new taxon. A crossvenational abnormality on an area of diagnostic significanc...

Ancient protein analysis is a rapidly developing field of research. Proteins ranging in age from the Quaternary to Jurassic are being used to answer questions about phylogeny, evolution, and extinction. However, these analyses are sometimes contentious, and focus primarily on large vertebrates in sedimentary fossilisation environments; there are fe...

Jumping bristletails (order Archaeognatha), the basalmost order of extant insects, include some of the earliest fossil records among hexapods, yet their overall geological occurrence remains sparse and has provided little insight into their evolution. The earliest representatives of crown‐group bristletails are those in Lebanese amber (Cretaceous),...

Portuguese amber has received very little attention from the paleontological and geological points of view. To our knowledge, only twelve amber outcrops or amber-bearing areas have been detected in Portugal. The first outcrops were cited in times as old as 1867 and 1910, and although some of them were considered Jurassic in age, most likely the amb...

Significance It is not known whether the fossil content of amber accurately represents the arthropod biodiversity of past forests, and if and how those fossils can be compared with recent fauna for studies and predictions of biodiversity change through time. Our study of arthropods (mainly insects and spiders) living around the resinous angiosperm...

All the amber outcrops of the Iberian Peninsula are Lower Cretaceous in age and, in the case of Spain, some of them have provided important arthropod specimens preserved as bioinclusions. These Spanish localities are rich in fossil taxa of phylogenetic relevance and evidence of both paleoecological interactions and paleobehaviors are also abundant....

Among the many challenges in paleobiology is the inference and reconstruction of behaviors that rarely, if ever, leave a physical trace on the environment that is suitable for fossilization. Of particular significance are those behaviors tied to mating and courtship, individual interactions critical for species integrity and continuance, as well as...

The originally published version of this Article was updated shortly after publication to add the word 'Ticks' to the title, following its inadvertent removal during the production process. This has now been corrected in both the PDF and HTML versions of the Article.

------------Open Access Article at: http://www.nature.com/articles/s41467-017-01550-z ------------- Ticks are currently among the most prevalent blood-feeding ectoparasites, but their feeding habits and hosts in deep time have long remained speculative. Here, we report direct and indirect evidence in 99 million-year-old Cretaceous amber showing th...

Amber is fossil resin that functioned as a trap, preserving ancient organisms with great fidelity even from the distant past. It represents a window into past biodiversity and ethology. Using artificial tree trunk sticky traps and natural resin emissions from the trees as amber analogues we studied in Madagascar some of the taphonomical processes t...

Purpose A new Iberian Konservat-Lagersta¨tte discovered in Tresjuncos (Cuenca, Spain) is described and interpreted based on geological and paleontological information. Methods The samples were studied using conventional mineralogical (powder X-ray diffraction), petrographic (optical and scanning electron microscopy) and geochemical (X-ray energy-di...

Parental care in animal evolution has long fascinated biologists, but tracing this complex of behavioural repertoires is challenging, as these transitory states often leave no corporeal traces as fossils. Among modern invertebrates, the tanaidaceans (Malacostraca: Peracarida), a lineage of marsupial crustaceans, show an interesting variety of brood...

Abundant gymnosperm pollen grains associated with the oedemerid beetle Darwinylus marcosi Peris, 2016 were found in Early Cretaceous amber from Spain. This discovery provides confirmatory evidence for a pollination mutualism during the mid Mesozoic for the family Oedemeridae (Coleoptera), which today is known to pollinate only angiosperms. As a res...

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During the mid-Cretaceous, angiosperms diversified from several nondiverse lineages to their current global domination [1], replacing earlier gymnosperm lineages [2].Several hypotheses explain this extensive radiation [3], one of which involves proliferation of insect pollinator associations in the transition from gymnosperm to angiosperm dominance...

Abstract: The Fourier Transform InfraRed spectroscopy (FTIR) analyses of five amber specimens found in the archaeological excavations carried out in Chamber II of Las Caldas cave (Province of Asturias, North of Spain), during 1983, 1984, 1988 and 1991, has been accomplished. These specimens, from the Middle to Upper Magdalenian (Upper Palaeolithic)...

Stable carbon-isotope geochemistry of fossilized tree resin (amber) potentially could be a very useful tool to infer the composition of past atmospheres. To test the reliability of amber as a proxy for the atmosphere, we studied the variability of modern resin δ¹³C at both local and global scales. An amber δ¹³C curve was then built for the Cretaceo...

Diverse assemblages of tanaidacean peracarid crustaceans from western Tethyan continental deposits suggest that the group was relatively common in or around ancient resin-producing forests. Here we report the results of an examination of 13 tanaidacean specimens from three Cretaceous (Albian to Turonian) French amber deposits. Two new species of th...

BCN Rocks is an application (App) for personal mobile devices (Android and iOS versions) suitable for secondary and high school students as well as people without background in Earth Sciences. The main objective of this App is to learn geology using the city facades and pavements of two emblematic spaces of the city of Barcelona, the Passeig de Grà...

The whole assemblage of beetles in the Cretaceous ambers of Western Europe (Spain and France) is surveyed for the first time

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The intense study of coleopteran inclusions from Spanish (Albian in age) and French (Albian–Santonian in age) Cretaceous ambers, both of Laurasian origin, has revealed that the majority of samples belong to the Polyphaga suborder and, in contrast to the case of the compression fossils, only one family of Archostemata, one of Adephaga, and no Myxoph...