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On Baltic amber inclusions treated in an autoclave

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  • Arbeitskreis Bernstein

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On Baltic amber inclusions treated in an autoclave Inclusions from Baltic amber processed in an autoclave are described, illustrated, and the various degrees of artificial modifications are commented upon. To inform entomologists and palaeontologists with less experience in amber and inclusions, general information on improved inclusions is given.
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POLISH JOURNAL OF ENTOMOLOG Y
POLSKIE PISMO ENTOMOLOGICZNE
VOL. 81: 165-183 Gdańsk 30 June 2012
DOI: 10.2478/v10200-012-0005-z
On Baltic amber inclusions treated in an autoclave
CHRISTEL HOFFEINS
Liseistieg 10, D-22149 Hamburg, Germany
chw.hoffeins@googlemail.com
ABSTRACT. Inclusions from Baltic amber processed in an autoclave are described, illustrated,
and the various degrees of artificial modifications are commented upon. To inform entomologists
and palaeontologists with less experience in amber and inclusions, general information on
improved inclusions is given.
KEY WORDS: Baltic amber, improved amber, autoclave, inclusions, artificial modification.
INTRODUCTION
Inclusions in Baltic amber open a fascinating window into the past of a vanished world.
Many people are attracted to the beautiful organisms entombed in a golden coffin. The
external characters of inclusions can be studied thanks to their preservation, which is almost
as good as examining living arthropods. This is why amber is so famous and treasured by
the public as well as by the scientific community.
In the last decade there have been increasing numbers of inclusions selected from
autoclave-treated amber. Autoclave processing, also referred to as “ennoblement” in the
sense of ‘upgrading’ the beauty and natural preservation of inclusions, is often a change in
the sense of “degradation”. Amber treated and clarified in autoclaves is marketed as
“improved” amber.
Why is an autoclave used for amber?
Amber companies use autoclaves to clarify opaque amber and to obtain a cognac-like
colour. Autoclaving works with pressures of 90-150BAR, the addition of nitrogen or argon
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gas and temperatures up to 200°C. Persons employed in this procedure need a high level of
experience if the desired result is to be obtained. Amber clarification also has
a long historical tradition: the Romans and medieval craftsmen used boiling oil or slowly
heated it in sand and salt beds.
Nowadays, a clear cognac- or honey-coloured amber is considered to be “typical”
amber and more precious, generally because most people are not familiar with the rich
variety of natural amber colours. On completion of the autoclave processing, clarified
amber inclusions, previously concealed in the opaque amber, become visible.
The prices for trade quantities of amber have increased year by year, so many
companies have started to treat large quantities of the so-called “Schlauben” or “sklejka”,
a cheaper quality of raw layered amber.
Layered amber was formed by successive resin flows outside the bark of the amber tree,
sometimes up to 100 in large samples, and the surface of each layer was as sticky as
flypaper. The percentage of inclusions is higher than normally found in unlayered amber
pieces. Schlauben are very brittle and cannot be cut for beads or other products. But after
treatment in an autoclave the layers are permanently bound, and can then be cut and
trimmed without difficulty or loss of prized material.
A side-effect of clarifying and Schlauben processing is the large amount of autoclaved
inclusion material available on the market.
Ordinary people buying amber products cannot usually see any differences between
natural and autoclaved amber, or between inclusions in their natural condition and those
treated in an autoclave.
But a scientist studying the fauna and flora embedded in Baltic amber may encounter
a problem, especially if he/she is inexperienced and studying inclusions for the first time.
The following considerations are general information about the changes taking place in
inclusions after improvement in autoclaves.
Artificial changes in amber after autoclave processing
During autoclave processing the amber is subjected to high pressure and high
temperature. What happens to the amber matrix itself inside such a furnace?
We cannot open the autoclave and check the microscopic details within an amber
sample while this treatment is going on. But we can document the results and interpret the
changes in the amber matrix, and test physical and chemical characteristics such as
hardness or amber acid content.
The main changes taking place in the amber matrix during autoclave processing are:
clarification by the diffusion of micro-bubbles;
the absence of amber acid, a typical component of Baltic amber;
the absence of the typical pine-resin smell;
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the intensification of pale colour of the resin flow layers to a brownish-orange hue,
while the main amber matrix remains watery and clear;
the occasional presence of bluish to greenish veils along the margins of resin flows
within layered amber.
Acknowledgements
My sincere thanks go to Prof. Ryszard Szadziewski for encouraging me to deal with
autoclaved inclusions and for his critical comments. My husband Hans Werner Hoffeins is
thanked for preparing some photographs and an anonymous reviewer for improving the
English draft.
MATERIAL AND METHODS
Christel & Hans Werner Hoffeins Collection, Hamburg, Germany (CCHH), to be
deposited at the Senckenberg Deutsches Entomologisches Institut, Müncheberg (SDEI).
The photographs were taken with a Nikon Coolpix 4500 attached to a Wild M3Z stereo-
microscope and edited with IrfanView.
RESULTS AND DISCUSSION
General remarks
A “natural“ inclusion is defined by the nearly exact original form of its outer shape (Fig.
1). We can find all degrees of preservation, ranging from the beautiful and perfect to the
scarcely identifiable. It depends upon the condition at the very moment when the organism
was entrapped by the flowing resin: alive and complete, dead, or already somewhat
decayed.
In contrast to compression fossils, inclusions in amber are fossilized in three
dimensions. The body lumen can be completely filled with resin or empty, the inner organs
decayed or partly mummified. In normal cases we find just the outer shape of arthropods,
like insects and spiders, including the cuticle with hairs, bristles and scales present in the
original position. Body and wings are discoloured except for the metallic colours in some
Coleoptera, the dipteran family Dolichopodidae and in the hymenopteran family Torymidae
(pers. observation). Rarely, wing markings are present as well, mostly in Cicadina,
Trichoptera, Mecoptera, Neuroptera, Blattodea, Embioptera and some Coleoptera
(WEITSCHAT & WICHARD 1998).
A phenomenon typical of Baltic amber inclusions is a milky coating or emulsion
(German term: “Verlumung“) obscuring the morphological details of the embedded
organisms. The cloudy coating occurs in all degrees of intensity, but often it just covers
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inclusions on one side, or more or less totally and around body openings such as spiracles,
terminalia and mouthparts. It is assumed that the milky emulsion is caused by the
decomposition of gases or general moisture surrounding the embedded organisms, not
exclusively found in insects and other arthropods but also in plants and plant debris. The
phenomenon was discussed in detail by SCHLÜTER & KÜHNE (1975) and MIERZEJEWSKI
(1978).
Fig. 1. Silvanidae (Coleoptera), undescribed sp., dorsal habitus, showing a vivid preservation in
natural amber, coll. 1698-4.
When amber is clarified in autoclaves, the embedded organic inclusions undergo an
artificial change.
As in a furnace, the high temperature can produce more or less severe deformations of
the embedded objects. The organisms are heated, dry out and finally roasted to be as burnt
as a broiled chicken. The surface of the inclusion turns dark brown and black; body and
legs are deformed, shrunk or compressed; bristles and hairs may have lost their original
point of insertion; the veins on the wings may be cracked and the delicate wing membrane
destroyed. Often the body and especially the wings are surrounded by an orange-brownish
aureole-like veil (Fig. 2). Inside the aureole there may be dark micro-fissures or micro-
cracks resembling tiny setulae.
Even if a fly's corpse and legs are shrunk, collapsed or deformed, the bristles on the
body remain their normal length, so the original ratio of measurements may change. This
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has to be taken into account, especially when identifying Diptera placed in the section
Acalyptratae (VON TSCHIRNHAUS & HOFFEINS 2009). The integument of the legs becomes
transparent so that mummified fragments are visible as thin black strings.
Fig. 2. cf. Asteiidae (Diptera: Acalyptratae), female, treated in an autoclave, coll. 668-4.
In the worst case, the inclusion may be totally deformed, blasted by heating into small
particles so that only the previous shape of the organism is present.
But we often find improved amber with inclusions that look almost like natural
inclusions, although it is quite obvious that the amber has been subjected to thermal
treatment. These organisms show just a low degree of alteration, if any at all. A possible
reason for this is the presence of a milky emulsion covering the inclusions. Consisting of
microbubbles and resin, the coating seems to act as a protective shell against strong heating.
After autoclave processing the microbubbles have disappeared by diffusion, have combined
to form larger ones or are filled with resin, so that the once-obscured organisms can now be
studied in detail. This physical alteration may explain the presence of irregularly shaped,
resin-filled and shiny bubbles adhering or close to autoclaved inclusions (Figs 5, 14). These
flat bubbles are quite different from those found in natural amber.
Also, it appears that Acari or Coleoptera and Blattodea are often protected against high
temperature and atmospheric pressure by their strong, sclerotized elytra, in contrast to more
delicate insects like Diptera, Aphidina and Thysanoptera.
Some observations have been made concerning the position of inclusions in relation to
the size of amber samples. An organism embedded closer to the surface of an amber piece
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shows a higher degree of roasting compared to inclusions positioned near the centre.
Organisms embedded in large amber samples some centimetres in size are often roasted to
a lesser degree than those in small cabochons of about 5-10 mm.
In general, autoclaved inclusions covered with or without a milky emulsion reveal
a broad range of gradual deformation, roasting and external damage.
In the following, some selected specimens, mainly dipteran inclusions, showing the
gradual alterations caused by autoclave processing are described, illustrated and
commented upon.
Case studies
Ceratopogonidae (Diptera), male, Forcipomyia sp., 1.8 mm
(Fig. 3)
The midge inclusion is embedded in a watery, clear amber; head, thorax and abdomen
with genitalia black and roasted; antenna, palpi and wing venation in good condition; legs
and basal abdominal segments transparent with internal black fragments; genital complex
discernible except for minute appendages inside the clasper.
Main diagnostic features present and identification to genus level possible.
Autoclave processing did not cause serious alterations.
Fig. 3. Ceratopogonidae (Diptera: Nematocera), Forcipomyia sp., male, coll. 179-2.
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Mycetophilidae (Diptera), Mycomyia sp., male, 5.3 mm
(Fig. 4)
The gnat inclusion is embedded in a multi-layered amber piece is in a somewhat
decayed condition, left eye with irregular rounded hole, a damage often seen in eroded
inclusions which were not covered totally by resin flow, tarsi and flagellomeres of antenna
partly disconnected. Thorax and coxae roasted and amorphous, without any morphological
details; palps, haltere and fore femur transparent, thorax, femora and tibia laterally
compressed; wings basally disarticulated, costa and radial veins partly cracked, wing
membrane partly lacerated; shape of sclerotized genitalia including all appendages intact,
some inner soft appendages transparent. Although the thorax is roasted and amorphous, the
right eye with ommatidia is complete and in a well preserved condition.
Autoclave processing did not cause serious alterations, identification to genus and even
species level possible due to the discernible genitalia complex.
The cracks and breakages in the wing membranes and the antenna do not appear natural
and most probably result from the autoclave process as wings of a recently trapped insect
would still be flexible in soft resin.
Fig. 4. Mycetophilidae (Diptera: Nematocera), Mycomyia sp., male, coll. 1735-4.
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Sciomyzidae (Diptera: Acalyptratae), cf. Phaeomyiinae, female, 4.4 mm
Syninclusion cf. Sminthuridae (Collembola), 0.7 mm
(Figs 5, 6)
The dipteran inclusion is complete with the right side of the thorax, head and all legs in
good condition, left side of body with eye, postcranium, proboscis, thorax and coxae
collapsed, no morphological details visible; antenna roasted, frons with frontal setae
obscured by a resin-filled transparent bubble; thorax slightly compressed laterally as seen in
the dorsal view, mesonotal proportions lengthened, transverse suture destroyed, surface of
mesonotum somewhat amorphous; thorax with humeral and presutural macrochaeta
disconnected, structure of left outer vertical and postalar bristles cracked; wings with radial
veins cracked, wing membrane broken up into several parts; abdomen with female cerci
well preserved.
Autoclave processing produced some artificial changes but identification to family and
subfamily level is possible due to the presence of the median anterior bristle on the mid
femur and short posterior setae on the hind tibia.
Next to the dipteran inclusion a minute collembola is embedded. The springtail
inclusion is totally destroyed; head with eyes and abdomen disconnected from the thorax,
eyes with body transparent, furca and antenna faint, diagnostic details not discernible.
Fig. 5. Sciomyzidae (Diptera: Acalyptratae), cf. Phaeomyiinae, female, coll. 1104-4.
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Fig. 6. cf. Sminthuridae (Collembola), syninclusion, coll. 1104-4.
Autoclave processing caused serious modifications; identification to family level
depends on the general habitus of the collembolan fragments.
In the amber piece with Diptera and Collembola inclusions we find two different
degrees of deformation. The large inclusion is more or less intact and shows just a low level
of deformation whereas the minute one is totally destroyed. We can assume that the degree
of artificial modification must be considered in relation to the size of an organism. Note:
the layered amber shows a highly intense orange-brown colouration along the margins of
the resin flows.
Stratiomyiidae (Diptera), Pachygastrinae, female, 2.5 mm
(Figs 7, 8)
A soldier fly inclusion embedded in a watery, clear amber, surrounded by a fine aureole;
head brownish to black and roasted, eyes not collapsed, antenna roasted, segmentation not
discernible but arista transparent and micro-morphological details present including apical
seta on tip; cervix somewhat elongated artificially; thorax black, roasted and laterally
compressed, without any morphological details, setosity of mesonotum distinct, legs
transparent with internal black fragments, wings in good condition with venation complete,
membrane dark orange-coloured; abdomen black and roasted, female terminalia indistinct
without any external details.
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Fig. 7. Stratiomyiidae (Diptera), Pachygastrinae, autoclaved female, lateral habitus, coll. 1350-2.
Fig. 8. Stratiomyiidae (Diptera), Pachygastrinae, female, lateral habitus, natural amber, body
obscured by milky coating, coll. 1350-1.
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Autoclave processing produced few artificial modifications but identification to family
and subfamily level possible due to wing venation. Compared to a conspecific stratiomyiid
inclusion (Fig. 8) in natural amber, the setosity of the mesonotum seems to be more intense.
cf. Pythidae (Coleoptera), 4 specimens, 1.5-2.5 mm
(Figs 9, 10)
Aggregation of four coleopteran inclusions in a watery, clear amber; three specimens
positioned close together near the reddish crust, with main morphological details present,
surrounded by a small orange-coloured aureole. A fourth specimen positioned separately
and with strongly roasted habitus; head, pronotum and prosternum with forelegs
disconnected from the corpse; head capsule black, shrunk and collapsed, palpi transparent,
antenna black; body black, shrunk and compressed, legs with tarsomeres brownish and
transparent, integument of coxae and femora cracked at bases; elytra black, abdominal
structure of sternites without any morphological details, reproductive organ extended, black
to brownish, destroyed. No morphological details discernible except those of the palpi and
antenna.
Identification to family level possible in the case of the three unaltered specimens; the
roasted specimen can be putatively assigned to the same family due to the shape of antenna.
Autoclave processing produced no discernible artificial modifications in three of the
four coleopteran inclusions, possibly because of the assumed milky emulsion covering and
protecting the inclusions. The reason why the fourth specimen shows severe alterations
remains speculative; perhaps it was positioned somewhat closer to the source of heating
inside the device than the other ones.
Rachiceridae (Diptera), cf. Electra formosa, ?male, 7.6 mm
(Figs 11, 12)
The dipteran inclusion is embedded in a watery, clear amber; apex of wings, terminalia
and hind legs partly cut-off. Head capsule with eyes black and collapsed with fragments of
ommatidia, pectinate antenna, basal antennomeres destroyed, remaining segments
complete; thorax and abdomen black, roasted, collapsed and destroyed with disconnected
fragments of the integument; legs transparent, collapsed, nearly flat, tibial spurs unaltered;
wings partly destroyed, veins including costa with many micro-cracks.
Morphological details absent except for antenna, thus identification possible to family
and genus level. Were the rachicerid-typical antenna completely destroyed, we would only
be able to identify this specimen as Diptera.
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Fig. 9. cf. Pythidae (Coleoptera), 4 specimens, coll. 1588-2
Fig. 10. cf. Pythidae (Coleoptera), roasted specimen, lateral habitus.
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Fig. 11. Rachiceridae (Diptera), cf. Electra formosa, autoclaved ?male, habitus, coll. 1398-1.
Fig. 12. Rachiceridae (Diptera, Brachycera), Electra formosa, male, head with antenna, natural
amber, coll. 1104-4.
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Culicidae (Diptera), Aedes hoffeinsorum SZADZIEWSKI 1998, holotype male, 6.1 mm
Syninclusion Pipunculidae (Diptera), female, 3.2 mm
(Figs 13-16)
Inclusions embedded in a clear multi-layered piece of amber with intense orange-
coloured resin layers. Culicid inclusion almost complete with two legs separated and close
to body; head and thorax roasted, ventrally covered by a thin whitish emulsion.
All diagnostic features, like proboscis, palpi, antenna, claws, wing venation including
scales, present and in good condition. Identification to family, genus and species level
possible; designated as a new species. A small spot of milky coating can explain the good
condition of the culicid inclusion in spite of the autoclave processing (see above).
Pipunculid syninclusion embedded in a destroyed condition with dorsally opened
corpse; dorsal surface of thorax and abdomen partly above a resin flow (visible from lateral
side), after entrapped in the resin the fly’s corpse was eroded by scavengers (see above).
Head with proboscis and typical big-headed fly eyes roasted, eyes irregularly collapsed,
fragments of ommatidia remaining as micro-punctured spots; antenna porrect with
elongated base, covered with long setae, postpedicellus roasted; fragments of thorax and
abdomen transparent with tatters of cuticula; femora and tibia of fore legs shrunk, mid and
hind legs black, pulvilli transparent; female terminalia with oviscape black and roasted, no
morphological details discernible.
Identification possible to family level due to the characteristic ventrally bent oviscape
present exclusively in Pipunculidae.
Fig. 13. Amber with Culicidae and Pipunculidae, coll. 1119.
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Fig. 14. Culicidae (Diptera), Aedes hoffeinsorum SZADZIEWSKI 1998, holotype male, dorsal habitus.
Fig. 15. Pipunculidae (Diptera), female, habitus.
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Fig. 16. Pipunculidae (Diptera), head, lateral view.
The presence of an elongated pedicellus gave rise to some questions (pers. com.
C. Kehlmaier, Dresden). It remains unclear whether the elongation is a morphological
character of the pipunculid inclusion or if the elongation was caused artificially by the
collapse of the head capsule during treatment in the autoclave.
Incertae sedis (Diptera: Acalyptratae), female, 2.3 mm
(Fig. 17)
Brachyceran inclusion embedded in a clear orange-coloured amber; head, thorax and
abdomen black, transparent fragments of integument reddish, all parts strongly roasted,
head and thorax somewhat imploded, but left eye with ommatidia almost intact, antenna
transparent, 4 long peristomal seta visible, palpi well preserved; thorax and abdomen
laterally compressed, original surface of mesonotum with bristle sticking in the resin above
the destroyed part, several macrochaeta cracked and disconnected from mesonotum and
head; legs partly transparent with complete setosity, femora cracked; wings partly
destroyed at hind margin, veins with cracks.
Autoclave processing produced severe changes; identification to family level not
possible because important morphological details mostly destroyed except for antenna,
peristomal setae and palpi.
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Fig. 17. Incertae sedis (Diptera, Acalyptratae), female, lateral habitus, coll. 1671-3.
The combination of plumose arista and 4 strong peristomal setae is present in
Anthoclusia gephyrea within Clusiidae (HENNIG 1965) and in Procyamops succini within
Periscelididae (HOFFEINS & RUNG 2005). As the other main diagnostic characters are
destroyed or not discernible, placement either in Clusiidae or Periscelididae thus remains
speculative.
CONCLUDING REMARKS
Inclusions in autoclaved or “improved“ amber show a broad range of artificial
modifications. The main effects in a negative sense are the roasting and shrinking of body
parts, black discolouration, collapsing mainly of head and eyes, compression of thorax, legs
and abdomen, cracking of veins in wings, disconnection of body segments and
macrochaeta.
Consequently, syninclusions embedded together in one piece of improved amber do not
show an identical degree of artificial modification.
The disconnection of diagnostic macrochaeta in acalyptrate Diptera is a serious
handicap in the identification to family, genus or species level.
If an inclusion is shrunk with many morphological details absent, some of the body
elements such as the antenna, cerci or terminalia, as well as the setosity, are present in
a well preserved condition. This is astonishing and difficult to explain.
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A positive effect of improving amber is the diffusion of the milky emulsion obscuring
many inclusions. On completion of thermal treatment, the inclusions are mostly visible with
the main morphological characters enabling the determination and even designation of
a new taxon, as seen in the case of Aedes hoffeinsorum.
The alterations illustrated and commented on above occur with a multitude of nuances.
The degree of artificial modification depends on the length of time, temperature, size of
amber, size of inclusion, position of inclusion, presence of milky emulsion or
a combination of these factors.
Another very serious problem is the autoclaving of sub-fossil copal material by
commercial companies. The autoclave process “ages” the soft sub-fossil resin, rendering its
properties similar to those of amber and making its identification as copal extremely
difficult, even with advanced analytical methods. Although the use of heat treatment on
a specific piece can be detected, whether or not the original starting material was copal or
amber still cannot be routinely identified (MCCLURE, KANE & STURMAN 2010: 223).
Inclusions embedded in copal are more “modern“ and related to the recent fauna. If such
material is offered for study and the original source cannot be recognized or the information
was lost in time and different trade channels, studies of these organisms may lead to very
serious misinterpretations and distorted results. The prohibition and banning of copal in the
amber industry should be upheld in all conditions and strictly controlled.
Palaeontologists study inclusions in Baltic amber worldwide and their published data
make our knowledge of the ancient amber forest, the palaeo-environment and the palaeo-
climate more clear and precise. Descriptions of new species based on material treated in an
autoclave have to be investigated carefully to avoid serious misinterpretations. Each
inclusion has to be checked individually. When identifying an insect or plant inclusion one
has to be sure whether a certain morphological character is a species-characteristic feature
or an effect of autoclave processing (SZWEDO & SONTAG 2009).
With regard to the great richness of inclusion material, this article is published as
general information for inclusion enthusiasts, collectors and specialists, indeed, for anyone
interested in the fascinating world embedded in Baltic amber. This article is intended to
inform entomologists and palaeontologists with less experience in amber, to help them
recognize the differences between “natural” and “improved” inclusions.
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MCCLURE S.F., KANE R.E., STURMAN N. 2010. Gemstone enhancement and its detection in the 2000s.
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der phylogenetischen Entwicklung dieser Dipteren-Gruppe. Stuttgarter Beiträge zur Naturkunde
145: 1-215.
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MIERZEJEWSKI P. 1978. Electron microscopy study on the milky impurities covering arthropod
inclusions in the Baltic amber. Prace Muzeum Ziemi, Prace geologiczne 28: 79-84.
SCHLÜTER T., KÜHNE W.G. 1975. Die einseitige Trübung von Harzinklusen – ein Indiz gleicher
Bildungsumstände. Entomologica Germanica, Stuttgart 2: 308-315.
SZADZIEWSKI R.1998. New mosquitoes from Baltic amber (Diptera: Culicidae). Polish Journal of
Entomology 67: 233-244.
SZWEDO J., SONTAG E. 2009. The traps of the “amber trap“. How inclusions could trap scientists with
enigmas. Denisia 26: 155-169.
VON TSCHIRNHAUS M., HOFFEINS C. 2009. Fossil flies in Baltic amber – insights in the diversity of
Tertiary Acalyptratae (Diptera, Schizophora), with new morphological characters and a key based
on 1,000 collected inclusions. Denisia 26: 171-212.
WEITSCHAT W., WICHARD W. 1998. Atlas der Pflanzen und Tiere in Baltischen Bernstein. Verlag Dr.
Friedrich Pfeil, München, 256 pp.
Received: March 16, 2012
Accepted: May 10, 2012
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... Presently, a large fraction of the Baltic amber material available has been treated with an autoclave to improve the transparency and general appearance of the amber (Hoffeins 2012). Unfortunately, this may alter the appearance of the specimens in fairly unpredictable ways, and may destroy much taxonomically relevant information (Hoffeins 2012). ...
... Presently, a large fraction of the Baltic amber material available has been treated with an autoclave to improve the transparency and general appearance of the amber (Hoffeins 2012). Unfortunately, this may alter the appearance of the specimens in fairly unpredictable ways, and may destroy much taxonomically relevant information (Hoffeins 2012). ...
Article
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Species of Bibionidae from Baltic amber are reevaluated based on newly discovered material, and a key to the species is given. Bibio succineus sp. nov. is described based on one male specimen, this is the first Bibio named from Baltic amber. The males of Hesperinus electrus Skartveit, 2009 and Penthetria montanaregis Skartveit, 2009 are redescribed. A single, autoclave treated specimen of Penthetria sp. is described but not formally named. Plecia tenuicornis Skartveit, 2009 is found to be a synonym of Plecia hoffeinsorum Skartveit, 2009, this species is recorded for the first time from Rovno amber, and both sexes of the species redescribed. Additional specimens of Plecia clavifemur Skartveit, 2009 and Dilophus crassicornis Skartveit, 2009 are described. Two female specimens probably belonging to the species discussed as Dilophus sp. by Skartveit (2009) are described, but not formally named.
... Up to now, only four species have been described, namely Airaphilus denticollis Ermisch, 1942 (probably belonging to Psammoecus Latreille, 1829), Dendrobrontes popovi Kirejtshuk, 2011, Mistran ot Alekseev & Bukejs, 2016, and Cathartosilvanus necromanticus Alekseev, 2017. Additionally, Silvanus sp. and Nausibius sp. have been reported from the Baltic amber, and the genus Cryptamorpha Wollaston, 1854 has been mentioned from Eocene Bitterfeld amber (Hope, 1836;Berendt, 1845;Menge, 1856;Helm, 1896;Handlirsch, 1908Handlirsch, , 1925Klebs, 1910;Bachofen-Echt, 1949;Larsson, 1978;Spahr, 1981;Hieke and Pietrzeniuk, 1984). ...
... The geological backgrounds of the Baltic and Bitterfeld amber deposits have recently been reviewed (Standke, 2008;Weitschat and Wichard, 2010), and the interconnectedness of these deposits has been assessed on the basis of arthropod inclusions (e.g., Hoffeins and Hoffeins, 2003;Szwedo and Sontag, 2013;Dunlop et al., 2018) and geochemistry (Wolfe et al., 2016). Amber from the former Palmnicken mine (Yatarny settlement, Kaliningrad, Russia) is part of a commercially mined deposit of Baltic amber. ...
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A new fossil species of the silvanid flat bark beetle genus Cathartosilvanus Grouvelle is described and illustrated from Baltic amber. Cathartosilvanus siteiterralevis sp. nov. differs from recent and fossil congeners in the distinct, sharp denticle found along its posterior pronotal angle. The phenomenon of specific body parts becoming disconnected, and the compression of specimens is briefly discussed and interpreted in the context of amber taphonomy. The specimen under study appears to be an uncommon case of a weakly sclerotized beetle imago becoming entrapped in resin shortly after moulting.
... The results of this process are apparent from the blackened appendages of the beetle that are distinctly deformed (particularly tibiae and tarsi), and from one of the synincluded Nematocera that has a roasted appearance. For details on the effect of autoclaving on amber fossils see Hoffeins (2012). Using micro-CT, the fossilized beetle body yields a contrast so that its external shape could only be coarsely imaged (Fig. 59). ...
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Of the 12 specimens of Calathus -like sphodrine beetles presently known from Baltic and Rovno amber deposits, 11 specimens were investigated using light microscopy, micro-CT scanning, and 3D imaging techniques. For the first time, many significant diagnostic characters of the external morphology and male and female genitalia of Eocene Sphodrini were studied in detail. Based on these data, three fossil species are diagnosed and placed in a natural group characterized by a derived pattern in elytral chaetotaxy and microsculpture and therefore the genus Quasicalathus Schmidt & Will, gen. nov. is described to comprise these species. Due to the presence of a styloid right paramere, Quasicalathus gen. nov. is considered a member of the sphodrine “P clade” of Ruiz et al. (2009). However, given the absence of synapomorphies of any species group of the P clade, the systematic position of Quasicalathus gen. nov. within this clade remains unresolved. The Baltic amber species Calathus elpis Ortuño & Arillo, 2009 is redescribed based on additional, fossil, non-holotype material and transferred to Quasicalathus gen. nov. Identification of the additional C. elpis fossil material remains slightly uncertain due to the non-availability of the holotype for direct comparison coupled with doubts regarding the accuracy of certain character states presented in its original description. Two species are newly described: Quasicalathus agonicollis Schmidt & Will, sp. nov., from Baltic amber, and Q. conservans Schmidt & Will, sp. nov., from Rovno amber.
... So-called "sun-sparks" are disk-shaped cracks created by heating in conjunction with a rapid change in pressure (Dahms, 1906;Wang et al., 2014). Autoclaving (combining heat and pressure) might not only damage amber and change its chemical properties (Wagner-Wysiecka, 2018), but also alter, shrink or darken its inclusions, so that certain characters are hardly visible after treatment (Hoffeins, 2012;Szwedo and Sontag, 2009). Like heating, a bath in boiling oil (e.g. ...
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Amber, a natural polymer, is fossil tree resin derived from diverse botanical sources with varying chemical compositions. As such, all amber is susceptible to the effects of light, temperature, relative humidity, and oxygen, as well as exposure to certain chemicals, and will deteriorate over time in collections if left unprotected. Here we review approaches for the conservation, preparation, and imaging of amber specimens and their inclusions, and address indications and causes of amber degradation, as well as recommendations for a suitable storage environment. We also provide updated preparation and embedding protocols, discuss several techniques for imaging inclusions, and address digitization efforts. A stable storage environment is essential to mitigate or avoid deterioration of amber, which often manifests as crazing, spalling, breaking and colour changes. Based on previous conservation studies of fossil resins, we generally recommend storage in a climate-monitored environment with a relative humidity of ca. 50%, 18 °C, and stress that light exposure must be kept to a minimum. For stabilization and anoxic sealing, amber specimens should ideally be embedded in an artificial epoxide resin (EpoTek 301-2 or similar is currently recommended). Amber should not be treated with or stored in vegetable or mineral oils (even for a short time for examination or photography), or come into contact with alcohol, disinfecting agents, hydrogen peroxide, or other destructive solvents or mixtures, since any of these materials can irreversibly damage the amber. Most photography of inclusions for research and digitization purposes can be successfully accomplished using light microscopy. Scanning electron microscopy (SEM) is sometimes used to uncover fine details, but is an invasive method. However, X-ray based methods (utilizing micro computed tomography, or micro-CT) are becoming more frequently used and increasingly indispensable in the examination of minute internal structures of inclusions, and to fully visualize important structures in opaque amber. Micro-CT makes it possible to digitize an inclusion three-dimensionally, and thus enables digital specimen ‘loans.’ Light microscopal images are still widely used in the digitization of amber specimens and are an essential alternative to micro-CT imaging when resources or time are limited. Overall, due to the vulnerability of all fossil resins, we recommend that conservation of amber samples and their inclusions be prioritized.
... Details of the holotype are hardly visible: a milky coating, debris, and the position of specimen in amber is adverse to optimal viewing. The amber of the Hoffeins collection was treated in autoclave before this examination, but without visible thermic modifications (Hoffeins, 2012). One male is in almost perfect condition with a view from the right, particularly of the terminalia. ...
Article
Bruchomyiinae is a subfamily of the Psychodidae (Diptera) with 57 extant and 19 extinct described species (Wagner & Stuckenberg, 2012, 2016). The core distribution area of extant species is the Neotropical region with almost 50 species in four genera. Six species in two genera are known from the Afrotropical region, and four species in one genus from the Oriental region (Polseela et al., 2018; Wagner & Stuckenberg, 2012, 2016). In the Nearctic and the Palearctic regions Bruchomyiinae are almost absent, with species occurrences only along the southern borders with sub-tropical climates.
... Comparison with main characters of amber Palaeopsylla reveals that it is more similar to P. dissimilis rather than to P. baltica and P. groehni. Amber with P. baltica was treated in autoclave (Hoffeins 2012), chaetotaxy of abdomen is not well preserved and it is a female. The striking feature of P. groehni, a group of spatulate setae on posterior margin of sternite IX, cannot be detected in previously documented images and drawing (JANZEN 2002 figs. ...
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Fossilised insects probably brought man’s attention since the prehistory, since first amber with an insect entombed in resin was found. Amber was collected and used by humans first in the Upper Paleolithic period, perhaps as long ago as 20,000 years (Beck et al., 2009; Burdukiewicz, 2009; Płonka & Kowalski, 2017). The written testimonies on amber inclusions goes back to Ancient Rome (Plinius Secundus, 77). During 17th and 18th centuries the inclusions in amber were noted by philosophers (Bacon, 1638), their values discussed and illustrated (e.g., Sendel, 1742) and their importance to understanding the history of life pointed (Kant in Hagen, 1821). Shortly after Linnaeus “Systema Naturae” editions, the first research using binomial names for insect included in the copal was published (Bloch, 1776) and Pleistocene record of Recent beetle was noted by Fabricius (1775). Notes and information on fossil insects from imprints and amber were presented by Lang (1708), Bertrand (1763), Linnaeus (1778) and Volta (1796). The first regular description of beetle inclusion in Baltic amber came from Gravenhorst (1806) and works of de Serres (1828, 1829) seems to be the first with more detailed overview and description of insects as adpression fossils. Therefore, human’s palaeoentomological interests predates official beginning of modern taxonomy and palaeoentomology as science is as old as modern entomology (Azar et al., 2018).
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Balticeler kerneggeri gen. nov. , sp. nov. , is described based on six fossil specimens preserved in Eocene Baltic amber and imaged using light microscopy and X-ray micro-computed tomography. Based on certain characters observed in the fossil species it is considered a “middle grade” Carabidae, outside of the large family Harpalinae (as it possesses a scrobal seta, the lack of which is a synapomorphy of that subfamily), but possessing four synapomorphies that indicate Balticeler belongs to a large clade of carabids including Harpalinae (anisochaetous Grade B antennal cleaner, conjunct mesocoxae, closed procoxal cavities, and a well-developed external lobe of the metepimeron). This remarkable beetle has several striking features, including lack of externally-visible sexually dimorphic characters, lack of lateral borders on the pronotum, and very long and thin mandibles and maxillae. In combination, these states are unique within Carabidae. We consider the presence of a dorsally completely open aedeagal median lobe as a synapomorphy of the fossil species with the subfamily Trechinae, a pubescent and relatively long second antennomere and a 4+2+2 pattern of umbilicate setae as synapomorphies of the supertribe Trechitae, and a quadrisetose clypeus as a synapomorphy with the Trechitae clade Bembidarenini + Trechini sensu Maddison et al. (2019). As it lacks a synapomorphy of Bembidarenini + Trechini, we propose that it is a member of the stem group of that clade.
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Six new extinct representatives of the family Melandryidae, namely Electroxylita chronographica gen. et sp. nov., Madelinia capillata sp. nov., Microscapha kugelanni sp. nov., Phloiotrya inmarinata sp. nov., Symphora pollocki sp. nov., and S. glaesonauta sp. nov. are described from inclusions in Eocene Baltic amber. Twenty-eight additional fossil specimens of melandryid beetles belonging to ten species are reported. A list of Melandryidae described from Baltic amber is compiled and an identification key is provided.
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Abstract: A review of specific publications dealing with Baltic amber Diptera, Acalyptratae, from the years 1822 until 2008 includes 38 articles. H. LOEW was the first entomologist searching systematically for Diptera in amber. Two of his three articles are discussed. Parts of his first one (1850) are translated from German because of its extreme rarity in libraries. From Eocene Baltic amber 35 families of acalyptrates are known now, a further four from British Eocene sediments. Natalimyzidae, ?Piophilidae and Pyrgotidae are recorded for the first time, Natalimyza was known only from the recent Afrotropical fauna. Different counts of the percentage of acalyptrates among insect-, Diptera- and “true fly“-inclusions, respectively, are compared. Less than 1% of all flies belong here. Reasons for this rarity are discussed together with an overview of the rare aggregation of acalyptrates in single amber pieces. Peculiar morphological apomorphies, which enable family identification worldwide because of their singularity, were already present during the Tertiary. Three such examples are discussed. The dispute about the doubted synchroneous genesis of German Bitterfeld amber is solved by demonstrating 15 conspecific acalyptrate species in both deposits. Intraspecific variability of an amber acalyptrate has never been studied before. On the basis of 45 specimens and the holotype of Protoscinella electrica (Chloropidae) the slowness of evolutionary transformations is exemplified with the background of the phylogenetic value of 16 selected characters. A spotlight is thrown on the polyphyletic reduction process in wing venation and bristle equipment observed in several families of acalyptrates. The systematic part presents overviews of a large number of morphological details used for taxonomy. Two tables enable the easy check and documentation of each detected specimen, as well as an understanding of the puzzling termini and abbreviation systems in subsequent periods of dipterology. Two differently organized identification keys are presented: one listing 97 exceptional, rare, or newly detected morphological pecularities, a second one is a trial to key out all 56 described and all 161 detected undescribed species. The well known terminology of HENNIG‘s publication series on amber is used in order to enable an easy cross-reference to his partly complicated descriptions, to his plentity of figures, and to the dipterous literature until the year 1981 when a new terminology was proposed. All family- and generic transfers since HENNIG‘s times are listed with their references, as well a species breakdown of parts of the identified 1,141 inclusions.
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A review of specific publications dealing with Baltic amber Diptera, Acalyptratae, from the years 1822 until 2008 in-cludes 38 articles. H. LOEW was the first entomologist searching systematically for Diptera in amber. Two of his three articles are discussed. Parts of his first one (1850) are translated from German because of its extreme rarity in libraries. From Eocene Baltic amber 35 families of acalyptrates are known now, a further four from British Eocene sediments. Natalimyzidae, ?Piophilidae and Pyrgotidae are recorded for the first time, Natalimyza was known only from the recent Afrotropical fauna. Different counts of the percentage of acalyptrates among insect-, Diptera-and " true fly " -inclusions, respectively, are compared. Less than 1% of all flies belong here. Reasons for this rarity are discussed together with an overview of the rare aggregation of acalyptrates in single am-ber pieces. Peculiar morphological apomorphies, which enable family identification worldwide because of their singularity, were already present during the Tertiary. Three such examples are discussed. The dispute about the doubted synchroneous genesis of German Bitterfeld amber is solved by demonstrating 15 conspecific acalyptrate species in both deposits. Intraspecific variability of an amber acalyptrate has never been studied before. On the basis of 45 specimens and the holotype of Protoscinella electrica (Chloropidae) the slowness of evolutionary transformations is exemplified with the background of the phylogenetic value of 16 selected characters. A spotlight is thrown on the polyphyletic reduction process in wing venation and bristle equipment observed in several families of acalyptrates. The systematic part presents overviews of a large number of morphological details used for taxonomy. Two tables enable the easy check and documentation of each detected specimen, as well as an understanding of the puzzling termini and abbreviation sys-tems in subsequent periods of dipterology. Two differently organized identification keys are presented: one listing 97 exceptional, rare, or newly detected morphological pecularities, a second one is a trial to key out all 56 described and all 161 detected unde-scribed species. The well known terminology of HENNIG's publication series on amber is used in order to enable an easy cross-ref-erence to his partly complicated descriptions, to his plentity of figures, and to the dipterous literature until the year 1981 when a new terminology was proposed. All family-and generic transfers since HENNIG's times are listed with their references, as well a species breakdown of parts of the identified 1,141 inclusions. Santrauka: 1822-2008 metais paskelbtos 38 moksline . s publikacijos, skirtos Baltijos gintare rastiems Diptera, Acalyptratae vabzdžiams. H. LOEWAS buvo pirmasis entomologas, sistematiškai tyrine . je ˛s dvisparnius gintare. Aptariami du iš triju˛ jo straipsniu˛. Atskiros jo pirmojo darbo (1850) dalys yra išverstos iš vokiečiu˛ kalbos, nes publikacija yra tapusi didele bibliografine retenybe. Iš eoceninio Baltijos gintaro dabartiniu metu žinomos 35 akaliptratiniu˛ dvisparniu˛ (Acalyptratae) šeimos. Dar trys rastos eocenine . se nuogulose Didžiojoje Britanijos. Agromyzidae, Natalimyzidae, Piophilidae, Pyrgotidae ir Sphaeroceridae yra aprašomos pirma˛ kar-ta˛, Natalimyza buvo žinoma tik iš dabartine . s Afrikos tropiku˛ faunos. Palyginami skirtingu˛ autoriu˛ pateikiami akaliptratu˛ gausu-mo paskaičiavimai tarp visu˛ vabzdžiu˛, dvisparniu˛ ir " tikru˛ju˛ musiu˛ " inkliuzu˛. Šioms muse . ms priklauso mažiau negu vienas pro-centas gintare randamu˛ inkliuzu˛. Šio retumo priežastys aptariamos kartu apžvelgiant retai pasitaikančias akaliptratu˛ sankaupas viename gintaro gabale. Ypatingos ir kartu unikalios morfologine . s apomorfijos, kuriomis pasižymi visos Žeme . s rutulyje sutinkamos akaliptratine . s muse . s, egzistavo jau terciare. Aptariami trys tokie pavyzdžiai. Diskusija apie abejotina˛ ta˛ pačia˛ vokiškojo Biterfel-do ir Baltijos gintaru˛ kilme ˛ išsprendžiama parodant, kad abiejuose gintaruose randama 15 vienodu˛ Acaliptratae ru – šiu˛. Vidinis ru – šinis variavimas tarp gintaruose randamu˛ akaliptratu˛ anksčiau nebuvo tirtas. Remiantis 45 pavyzdžiais ir Protoscinella electrica (Chloropidae) holotipu demonstruojamas evoliuciniu˛ transformaciju˛ le . tumas kartu pagrindžiant 16 parinktu˛ požymiu˛ filogeneti-ni ˛ reikšminguma˛. Nušviečiamas polifiletinis sparno gyslotumo ir šeriuotumo redukcijos procesas, stebimas keliose akaliptratu˛ šei-mose. Denisia 26, zugleich Kataloge der oberösterreichischen Landesmuseen Neue Serie 86 (2009): 171–212
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Advances in technology and increased demand for lower-priced gem materials contributed to the proliferation of new treatments throughout the first decade of the 2000s. The developments that made the most difference were the diffusion treatment of corundum with beryllium, diffusion of copper into feldspar, clarity enhancement of ruby and diamond, and heat treatment of diamond, ruby, and sapphire. Gemological laboratories and researchers have done their best to keep up with these treatments, and the jewelry trade has struggled with how to disclose them. This article summarizes these developments and the methods used to identify the various enhancements
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In addition to the previously known Culex erikae from Eocene Baltic amber three new species of fossil mosquitoes are described. They are: Aedes hoffeinsonnn sp. Aedes damzeni sp.n. and Aedes serafini sp. n. They all belong to the subgenus Finlaya. In the extant fauna mosquitoes of that subgenus are most diversified in the Oriental lgion. Their larvae live in small water bodies in tree hollows, leaf axils.. etc. and usually are not common in their habitats. This may explain why mosquitoes are so rare among inclusions in Baltic amber,
Die einseitige Trübung von Harzinklusen -ein Indiz gleicher Bildungsumstände
  • Schlüter T
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SCHLÜTER T., KÜHNE W.G. 1975. Die einseitige Trübung von Harzinklusen -ein Indiz gleicher Bildungsumstände. Entomologica Germanica, Stuttgart 2: 308-315.
The traps of the "amber trap". How inclusions could trap scientists with enigmas
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SZWEDO J., SONTAG E. 2009. The traps of the "amber trap". How inclusions could trap scientists with enigmas. Denisia 26: 155-169.
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Electron microscopy study on the milky impurities covering arthropod inclusions in the Baltic amber
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MIERZEJEWSKI P. 1978. Electron microscopy study on the milky impurities covering arthropod inclusions in the Baltic amber. Prace Muzeum Ziemi, Prace geologiczne 28: 79-84.