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Jane Richter - One of the best experts on this subject based on the ideXlab platform.
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Hydrolysis of Baltic Amber during thermal ageing--an infrared spectroscopic approach.
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2013Co-Authors: Gianluca Pastorelli, Yvonne Shashoua, Jane RichterAbstract:Abstract To enable conservation of Amber in museums, understanding of chemical changes is crucial. While oxidation has been investigated particularly well for this natural polymer, further degradation phenomena in relation to humidity and pollutants are poorly studied or still unknown. Attenuated total reflectance-Fourier transform infrared spectroscopy was explored with regard to Baltic Amber. A systematic spectroscopic survey of a wide range of thermally aged model Amber samples, exposed to different microclimatic conditions, showed significant changes in their spectra. Samples aged in a humid and acidic environment or exposed to a humid and alkaline atmosphere generally exhibited a higher absorbance intensity of carbonyl groups at frequencies assigned to acids than unaged samples, samples aged in drier conditions and samples immersed in an alkaline solution. Baltic Amber comprises succinate ester, which may be hydrolysed into communol and succinic acid. The survey thus provided evidence about the progress of hydrolytic reactions during degradation of Baltic Amber. Infrared spectroscopy was shown to have significant potential for providing qualitative and quantitative chemical information on hydrolysis of Amber, which will be of interest for the development of preventive conservation techniques for museum collections of Amber objects.
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Hydrolysis of Baltic Amber during thermal ageing – An infrared spectroscopic approach
Spectrochimica acta. Part A Molecular and biomolecular spectroscopy, 2013Co-Authors: Gianluca Pastorelli, Yvonne Shashoua, Jane RichterAbstract:To enable conservation of Amber in museums, understanding of chemical changes is crucial. While oxidation has been investigated particularly well for this natural polymer, further degradation phenomena in relation to humidity and pollutants are poorly studied or still unknown. Attenuated total reflectance-Fourier transform infrared spectroscopy was explored with regard to Baltic Amber. A systematic spectroscopic survey of a wide range of thermally aged model Amber samples, exposed to different microclimatic conditions, showed significant changes in their spectra. Samples aged in a humid and acidic environment or exposed to a humid and alkaline atmosphere generally exhibited a higher absorbance intensity of carbonyl groups at frequencies assigned to acids than unaged samples, samples aged in drier conditions and samples immersed in an alkaline solution. Baltic Amber comprises succinate ester, which may be hydrolysed into communol and succinic acid. The survey thus provided evidence about the progress of hydrolytic reactions during degradation of Baltic Amber. Infrared spectroscopy was shown to have significant potential for providing qualitative and quantitative chemical information on hydrolysis of Amber, which will be of interest for the development of preventive conservation techniques for museum collections of Amber objects.
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Evidence concerning oxidation as a surface reaction in Baltic Amber.
Spectrochimica acta. Part A Molecular and biomolecular spectroscopy, 2012Co-Authors: Gianluca Pastorelli, Jane Richter, Yvonne ShashouaAbstract:Abstract The aim of this study was to provide evidence about oxidation as a surface reaction during degradation of Baltic Amber. A clear understanding of the Amber–oxygen interaction modalities is essential to develop conservation techniques for museum collections of Amber objects. Pellet-shaped samples, obtained from pressed Amber powder, were subjected to accelerated thermal ageing. Cross-sections of the pellets were analyzed by infrared micro-spectroscopy, in order to identify and quantify changes in chemical properties. The experimental results showed strong oxidation exclusively at the exterior part of cross-sections from samples subjected to long-term thermal ageing, confirming that oxidation of Baltic Amber starts from the surface.
George Poinar - One of the best experts on this subject based on the ideXlab platform.
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A gilled mushroom, Gerontomyces lepidotus gen. et sp. nov. (Basidiomycota: Agaricales), in Baltic Amber.
Fungal biology, 2016Co-Authors: George PoinarAbstract:A densely scaled small mushroom in Baltic Amber is described as Gerontomyces lepidotus gen. et sp. nov. and is characterized by a convex pileus 1.0 mm in diameter, distant to subdistant lamellae with smooth margins and a centrally inserted cylindrical, solid stipe. Its taxonomic placement is uncertain. This is the first mushroom described from Baltic Amber.
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New fossil nematodes in Dominican and Baltic Amber
Nematology, 2012Co-Authors: George PoinarAbstract:Four new species of fossil mermithids (Nematoda: Mermithidae) are described from Amber: Heydenius arachnius n. sp. from a spider (Arachnida: Araneae) in Dominican Amber, H. phasmatophilus n. sp., from a walking stick (Phasmatodea: Phasmatidae) in Baltic Amber, H. podenasae n. sp. from a moth (Lepidoptera) in Baltic Amber and H. trichorosus n. sp. from a caddis fly (Trichoptera: Leptoceridae) in Baltic Amber. With previous descriptions of fossil mermithids from Diptera, Coleoptera, Hymenoptera and Hemiptera, there are now representatives of seven insect orders as hosts of fossil mermithids. With these additional four fossils, the total number of described nematode fossils is now 95, with 70 occurring in Amber.
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Using fossils to determine an Amber source: aphids and crane flies in Chinese or Baltic Amber?
Historical Biology, 2011Co-Authors: O. E. Heie, George PoinarAbstract:Aphids and crane flies in Amber purported to have originated in China were examined. Six aphid specimens were characterised and determined to be conspecific with Germaraphis defuncta Heie, originally described from Baltic Amber. Two crane flies from the same collection were identified as Cheilotrichia minuta and Rhabdomastix brevis, species also previously described from Baltic Amber. This study shows that when the locality of an Amber source is ambiguous, fossils can be used to determine the true province.
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The first fossil opilioacariform mite (Acari: Opilioacariformes) and the first Baltic Amber camel spider (Solifugae)
Transactions of The Royal Society of Edinburgh-earth Sciences, 2003Co-Authors: Jason A. Dunlop, Jörg Wunderlich, George PoinarAbstract:The first fossil opilioacariform mite (Acari: Opilioacariformes), Paracarus pristinus sp. n., is described from Baltic Amber (Tertiary: Eocene). This well-preserved inclusion has six eyes and, thus, can be excluded from the derived, four-eyed genera. Based on characters such as the extremely long leg 4, it is assigned to the extant central Asian genus Paracarus ChAmberlin & Mulaik, 1942. As with many Baltic Amber inclusions, we lack an exact provenance for the type specimen, but the Baltic region is further north than the present day range of Recent opilioacariform species and suggests that the range of this group was once more extensive within Eurasia. The first solifuge (Solifugae) from Baltic Amber is described as Palaeoblossia groehni gen. et sp. n. Based on its size and general appearance, it can be assigned to Daesiidae, and again represents an arachnid group which previously had a much wider geographical range. If adult, it may represent the smallest solifuge known.
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Fossil palm flowers in Dominican and Baltic Amber
Botanical Journal of the Linnean Society, 2002Co-Authors: George PoinarAbstract:Five palm flowers in Dominican Amber and one in Baltic Amber are described or characterized. Palaeoraphe dominicanagen. et sp. nov. in the subtribe Livistoninae, is described from one perfect flower in Dominican Amber. Roystonea palaeasp. nov. is described from one staminate and one pistillate flower in Dominican Amber. Three other palm flowers, two perfect flowers from Dominican Amber and one staminate flower from Baltic Amber, are briefly characterized and figured. © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society, 2002, 139, 361–367.
Andris Bukejs - One of the best experts on this subject based on the ideXlab platform.
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Two new species of Xyletinus Latreille (Ptinidae: Xyletininae) in Eocene Baltic Amber.
Zootaxa, 2019Co-Authors: Vitalii I. Alekseev, Andris BukejsAbstract:New species of the genus Xyletinus Latreille, 1809, namely X. (s.str.) besseli sp. nov. and X. (s.str.) barsevskisi sp. nov., from Eocene Baltic Amber, are described and illustrated.
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Groehnius , a new genus of Eugnomini (Coleoptera: Curculionidae) from Eocene Baltic Amber
Fossil Record, 2019Co-Authors: Andris Bukejs, Andrei A LegalovAbstract:Abstract. A new weevil, Groehnius electrum Bukejs and Legalov, gen. et sp. nov. (Coleoptera: Curculionidae: Curculioninae), is described from Eocene Baltic Amber. This new genus is similar to the genus Archaeoeugnomus Legalov, 2016 from Baltic Amber but differs in the femora without ventral teeth, and the scape not reaching the anterior margin of the eye. It is the second record of the tribe Eugnomini in the Eocene.
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A new species of Globicornis Latreille (Coleoptera: Dermestidae) from Baltic Amber, with a key to fossil species.
Zootaxa, 2018Co-Authors: Andris Bukejs, Jiří HávaAbstract:Based on a well-preserved specimen from Eocene Baltic Amber, the fourth fossil species belonging to the genus Globicornis Latreille (Coleoptera: Dermestidae: Megatominae), G. groehni sp. nov., is described and illustrated. A key to the species of Globicornis known from Baltic Amber is also provided. The addition of this species further improves our knowledge about dermestids in Baltic Amber, and moves us closer to the level of taxonomic coverage needed for detailed ecological studies based upon the coleopteran assemblage within the deposit.
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A new species of Eupariini from Eocene Baltic Amber (Coleoptera: Scarabaeidae: Aphodiinae).
Zootaxa, 2017Co-Authors: Vytautas Tamutis, Vitalii I. Alekseev, Andris BukejsAbstract:Based on 10 specimens from Late Eocene Baltic Amber, an extinct species of Eupariini (Coleoptera: Scarabaeidae: Aphodiinae), Airapus lithuanicus Tamutis, Alekseev, & Bukejs new species, is described and illustrated. The new species is compared with two known fossil representatives of Aphodiinae from Baltic Amber. The generic placement of these two species, Saprosites succini (Zang, 1905) and Ataenius europaeus Quiel, 1910, is discussed, as are details of paleoecology for the new species.
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Contributions to the palaeofauna of Ptinidae (Coleptera) known from Baltic Amber
Zootaxa, 2017Co-Authors: Andris Bukejs, Vitalii I. Alekseev, David M.l. Cooper, Gavin A. King, Ryan C. MckellarAbstract:Hemicoelus favonii sp. nov. is described and illustrated from Eocene Baltic Amber. This new fossil species differs from extant congeners in having 11-segmented antennae; a metathoracic ventrite with large impression in its anterior portion; a pronotum distinctly narrower than the elytral base region; the posterior suture of abdominal ventrite 1 weakly arcuate medially; sharp lateral pronotal margins that are incomplete and distinct in their basal half only; elytral striae that are not grouped in pairs; posterior pronotal angles that are rounded; elytral intestriae 3, 5, 7 and 9 that are distinctly convex; and a comparatively small total body size. The presence of Hemicoelus in Baltic Amber suggests that moist, rotting wood was available as a microhabitat in the ancient forest. Beyond the new species description, the systematic placement of Anobium jacquelinae Hawkeswood, Makhan & Turner is discussed. A new fossil record for Microbregma waldwico Bukejs & Alekseev, and the first report of the genus Trichodesma LeConte from Eocene Baltic Amber are also presented.
Gianluca Pastorelli - One of the best experts on this subject based on the ideXlab platform.
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Hydrolysis of Baltic Amber during thermal ageing--an infrared spectroscopic approach.
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2013Co-Authors: Gianluca Pastorelli, Yvonne Shashoua, Jane RichterAbstract:Abstract To enable conservation of Amber in museums, understanding of chemical changes is crucial. While oxidation has been investigated particularly well for this natural polymer, further degradation phenomena in relation to humidity and pollutants are poorly studied or still unknown. Attenuated total reflectance-Fourier transform infrared spectroscopy was explored with regard to Baltic Amber. A systematic spectroscopic survey of a wide range of thermally aged model Amber samples, exposed to different microclimatic conditions, showed significant changes in their spectra. Samples aged in a humid and acidic environment or exposed to a humid and alkaline atmosphere generally exhibited a higher absorbance intensity of carbonyl groups at frequencies assigned to acids than unaged samples, samples aged in drier conditions and samples immersed in an alkaline solution. Baltic Amber comprises succinate ester, which may be hydrolysed into communol and succinic acid. The survey thus provided evidence about the progress of hydrolytic reactions during degradation of Baltic Amber. Infrared spectroscopy was shown to have significant potential for providing qualitative and quantitative chemical information on hydrolysis of Amber, which will be of interest for the development of preventive conservation techniques for museum collections of Amber objects.
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Hydrolysis of Baltic Amber during thermal ageing – An infrared spectroscopic approach
Spectrochimica acta. Part A Molecular and biomolecular spectroscopy, 2013Co-Authors: Gianluca Pastorelli, Yvonne Shashoua, Jane RichterAbstract:To enable conservation of Amber in museums, understanding of chemical changes is crucial. While oxidation has been investigated particularly well for this natural polymer, further degradation phenomena in relation to humidity and pollutants are poorly studied or still unknown. Attenuated total reflectance-Fourier transform infrared spectroscopy was explored with regard to Baltic Amber. A systematic spectroscopic survey of a wide range of thermally aged model Amber samples, exposed to different microclimatic conditions, showed significant changes in their spectra. Samples aged in a humid and acidic environment or exposed to a humid and alkaline atmosphere generally exhibited a higher absorbance intensity of carbonyl groups at frequencies assigned to acids than unaged samples, samples aged in drier conditions and samples immersed in an alkaline solution. Baltic Amber comprises succinate ester, which may be hydrolysed into communol and succinic acid. The survey thus provided evidence about the progress of hydrolytic reactions during degradation of Baltic Amber. Infrared spectroscopy was shown to have significant potential for providing qualitative and quantitative chemical information on hydrolysis of Amber, which will be of interest for the development of preventive conservation techniques for museum collections of Amber objects.
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Evidence concerning oxidation as a surface reaction in Baltic Amber.
Spectrochimica acta. Part A Molecular and biomolecular spectroscopy, 2012Co-Authors: Gianluca Pastorelli, Jane Richter, Yvonne ShashouaAbstract:Abstract The aim of this study was to provide evidence about oxidation as a surface reaction during degradation of Baltic Amber. A clear understanding of the Amber–oxygen interaction modalities is essential to develop conservation techniques for museum collections of Amber objects. Pellet-shaped samples, obtained from pressed Amber powder, were subjected to accelerated thermal ageing. Cross-sections of the pellets were analyzed by infrared micro-spectroscopy, in order to identify and quantify changes in chemical properties. The experimental results showed strong oxidation exclusively at the exterior part of cross-sections from samples subjected to long-term thermal ageing, confirming that oxidation of Baltic Amber starts from the surface.
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Archaeological Baltic Amber: degradation mechanisms and conservation measures
2009Co-Authors: Gianluca PastorelliAbstract:The aim of this project was to achieve a deep understanding of the mechanisms by which Baltic Amber degrades, in order to develop techniques for preventive conservation of archaeological Amber objects belonging to the National Museum of Denmark’s collections. To examine deterioration of Baltic Amber, a starting point was to identify and monitor surface and bulk properties which are affected during degradation. The way to operate consisted of the use of accelerated ageing to initiate degradation of raw Baltic Amber samples in different conditions of relative humidity, oxygen exposure or pH and, successively, of the use of non/micro-destructive techniques to identify and quantify changes in visual, chemical and structural properties. A large piece of raw Baltic Amber was used to prepare several test samples for two different kinds of accelerated ageing: thermal-ageing and photo-ageing. During the ageing, Amber samples were regularly examined through several analytical techniques related to different information: appearance/colour change by visual examination, photography and colorimetry; chemical change by infrared spectroscopy, Raman spectroscopy and elemental analysis; rate of oxidation by oxygen measurement; qualitative analysis of released volatiles by gas chromatography – mass spectrometry. The obtained results were analysed through both critical evaluation and statistical study. After the interpretation of the achieved data, the main relations between Amber and environmental factors during the degradation process became clearer and it was possible to identify the major pathways by which Amber degrades, such as hydrolysis of esters into alcohols and carboxylic acids, thermal-oxidation and photo-oxidation of terpenoid components, depolymerisation and decomposition of the chemical structure. At the end it was possible to suggest a preventive conservation strategy based on the control of climatic, atmospheric and lighting parameters in the environment where Baltic Amber objects are stored and displayed.
Iwona Kania - One of the best experts on this subject based on the ideXlab platform.
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A new species of Bruchomyiinae (Diptera: Psychodidae) from Baltic Amber.
Zootaxa, 2020Co-Authors: Kornelia Skibińska, Ryszard Szadziewski, Iwona Kania, Wiesław KrzeminskiAbstract:Bruchomyiinae is one of seven subfamilies of Psychodidae. This small group comprises fewer than 60 extant species distributed mainly in tropical and sub-tropical regions (Wagner Stuckenberg 2016). All life stages of these flies are closely tied to forest environment (Fairchild 1952; Stuckenberg 1962) and as a result, bruchomyiines are frequently preserved in fossil resins. The first fossil member of this subfamily was described from Baltic Amber (45 Ma) (Meunier 1905) and Burmese Amber (100 Ma) is the oldest fossil resin in which representatives of Bruchomyiinae have been found (Stebner et al. 2015; Wagner 2017; Skibinska et al. 2019). Due to the relative scarcity of this subfamily in Baltic Amber, any new specimens are of great interest. Up till now, there are only 12 bruchomyiine species described from Baltic Amber. Wagner (2017) completed a revision of fossil Bruchomyiinae and proposed the genus Hoffeinsodes to include the species having male genitalia with gonocoxites fused with hypandrium. In this genus, he classified six species reported exclusively from Eocene Baltic Amber: H. bifida Wagner, 2017, H. cubicula Wagner, 2017, H. longicauda Wagner, 2017, H. obtusa Wagner, 2017, H. reducta Wagner, 2017 and H. hoffeinsi (Wagner, 2006) transferred from Nemopalpus (Wagner, 2006). Here, we describe a new species belonging to this genus.
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Subfamily Limoniinae Speiser, 1909 (Diptera, Limoniidae) from Baltic Amber (Eocene): the genus Helius Lepeletier & Serville, 1828.
Zootaxa, 2014Co-Authors: Iwona KaniaAbstract:A revision of the genus Helius Lepeletier & Serville, 1828 (Diptera: Limoniidae) from Baltic Amber (Eocene) is presented. Redescriptions of 5 species, Helius formosus Krzemiński, 1993, Helius linus Podenas, 2002, Helius minutus (Loew, 1850), Helius mutus Podenas, 2002, Helius pulcher (Loew, 1850) of this genus from Baltic Amber are given and documented by photographs and drawings. Four new species of the genus Helius from Baltic Amber are described: Helius gedanicus sp. nov., Helius hoffeinsorum sp. nov., Helius similis sp. nov., Helius fossilis sp. nov. A key to species of Helius from Baltic Amber is provided. Patterns morphological evolution and the aspects evolutionary history of Helius are discussed.
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Subfamily Limoniinae Speiser, 1909 (Diptera, Limoniidae) from Baltic Amber (Eocene): the genus Dicranomyia Stephens, 1829
Zoological Journal of the Linnean Society, 2014Co-Authors: Iwona KaniaAbstract:A revision of the genus Dicranomyia Stephens, 1829 (Diptera: Limoniidae) from Baltic Amber (Eocene) is presented. Redescriptions of nine species of this genus from Baltic Amber are given and documented with photographs and drawings. Four novel species of the genus Dicranomyia from Baltic Amber are described. The newly described species among the subgenus Dicranomyia are: Dicranomyia (D.) Baltica sp. nov., Dicranomyia (D.) ewa sp. nov., and Dicranomyia (D.) succinica sp. nov. One new species belongs to the subgenus Melanolimonia Alexander, 1965, Dicranomyia (Melanolimonia) krzeminskii sp. nov., as the first representative of this subgenus in Baltic Amber. The male of Dicranomyia (D.) graciosa is found and described. A cladistic analysis of species belonging to the genus Dicranomyia from Baltic Amber based on 37 morphological characters and 14 species is given. A key to species of Dicranomyia from Baltic Amber is provided. The ecological pattern and biogeographical and evolutionary aspects of Dicranomyia are discussed. © 2014 The Linnean Society of London
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New taxa of Tanyderidae (Diptera) from Eocene Baltic Amber
Zootaxa, 2013Co-Authors: Wiesław Krzeminski, Ewa Krzemińska, Iwona Kania, Andrew J. RossAbstract:Macrochile hornei sp. nov. from Baltic Amber (Upper Eocene) is described and illustrated. Podemacrochile gen. nov. is described with Podemacrochile Baltica (Podenas, 1997) as type species. A key to the genera and species of Tanyderidae known from Baltic Amber is presented.
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A new species of Palaeopoecilostola Meunier, 1899 (Diptera: Limoniidae) from the Eocene Baltic Amber
Zootaxa, 2012Co-Authors: Iwona Kania, Wiesław KrzeminskiAbstract:A new species of the genus Palaeopoecilostola Meunier, 1899 (Diptera: Limoniidae) from the Baltic Amber (Upper Eocene) is described. The cladistic analysis of the species included in this genus is provided. The distributional pattern of the Palaeopoecilostola species is discussed. Palaeopoecilostola as numerous and remarkable representative of Limoniidae, can be treated as the marker genus of the Baltic Amber in broad sense (including Bitterfeld and Ukrainian Ambers). Anepsiomyia atterraneus Nazarov, 1994 is resurrected from synonymy with Palaepoecilostola speciosa Meunier, 1906. Ryta berestiana Nazarov, 1994 appears a junior synonym of Palaepoecilostola speciosa Meunier, 1906.
